MikeCAdministrator
(Admin)
Mon Aug 22 2011 06:53 AM
Irene Strengthens to a Category 2 Hurricane

11PM EDT Update 22 August 2011
The 11PM official track is out.

There is no real change to the forecast, it is just further along on the points in time, nor changes to watches and warnings.

It appears that the hurricane center is waiting for the next model runs with the Gultstream and Air Force dropsonde data to make any real change, which seems wise.

The Intensity forecast is up in the near term, now a cat 4 projected over the Bahamas, then it weakens to cat 3 north, and eventually approaches the NC/SC border Saturday evening.

If tropical storm or hurricane watches were to go up for Irene in Florida, they would likely come sometime tomorrow afternoon to fit in the 48.watch window.

8PM EDT Update 22 August 2011
From Recon Reports, Hurricane Irene has strengthened to a Category 2 hurricane with 100MPH winds.



Recon now reports a closed eyewall within Irene as the microwave imagery shows. It is likely to become a major hurricane tomorrow.



Note: We plan to turn on the site's disaster mode tomorrow which will limit certain features, but most things will still remain available. A disaster thread has been started for preparation help and questions.

11AM EDT Update 22 August 2011
Hurricane warnings are now up for the Turks and Caicos islands, and the southeastern Bahamas.

The 11AM official forecast now has moved eastward and forecasts a major hurricane in the Northern Bahamas, with eventual landfall near Charleston, South Carolina dawn on Saturday.

Much of the southeast remains in the cone, but the chances for direct impact in Florida is much less today than it was yesterday.

However, they are now forecasting a major hurricane approaching the coast of South Carolina. Those in the Coastal Carolinas (both North and South) may want to start making preparation plans in case landfall is near you, those in Florida and Georgia should already have them laid out in case a more westerly solution occurs but this is beginning to look much less likely. A stronger system would imply a turn north sooner than a weaker one (which was the old forecast), therefore Florida may escape the worst of the storm, but still get high surf from it passing through the Bahamas.

Those in the rest of the southeast will want to monitor for changes, but the trends still remain on the eastern side of the cone.

Original Update
Hurricane Irene has formed near Peurto Rico this morning as it provided an extremely rough evening across the entire island. The hurricane is now north of the western side of the ilsand, moving generally west northwest.

Some preliminary reports from Peurto Rico indicated widespread tree and power line damage, and over 800 thousand homes are without power there. See stormcarib for more reports from the islands.

The strongest side of Irene continues to be the northern side, with most of the convection pushing northward, the current forecast track moves along the northern coast of Hispaniola, where Hurricane Warnings are up for, and puts most of the Bahamas in the northern side of the storm. There is still some disagreement in models and thinking about how far west the system makes it. The current split the middle forecast is what the official forecast says, it still puts most of the southeast US on standby for the hurricane. It may not be until Tuesday or Wednesday before a clear path is known.



With the new forecast path, it does not spend as much time near Hispaniola, and with the very impressive outflow setup (similar to what is usually found in west Pacific storms) the poor south side is really the largest negative factor for development. There is a very good possibility that Irene will become a very large (size wise) major hurricane. MIMIC microwave imagery also suggests that the system is well protected from dry air intrusion which would be something to look for to keep it weaker that does not exist.

The ridging north of the system is strong which would imply generally westward movement, and we cannot say it will definitely move east of Florida (but odds are increasing that it will stay east), so again, the error in the cone can be 250 miles wide (east and west) at the end and anyone in Florida up to North Carolina should be watching Irene closely. The models have trended east, but the official track is still close to Florida, hopefully the trend to the east continues today.

The noaa Gonzo Gulfstream IV jet is taking off today from MacDill AFB in Tampa, it will sample the atmosphere in front of Irene, and hopefully will be able to be ingested into the "0Z" models run overnight.

Updates to come throughout the day.

Harvey has made second landfall in Mexico as a tropical depression, it is expected to dissipate later today over land.

{{StormCarib}}


FAA / wx underground San Juan Radar

Added radar recording of Puerto Rico long range radar here.

Leewards/Martinique Radar recording for Irene Approach

See the Forecast Lounge for more speculation on Irene.

{{StormLinks|Irene|09|9|2011|2|Irene}}

{{StormLinks|Harvey|08|8|2011|1|Harvey}}

{{StormLinks|98L|98|10|2011|3|98L}}


Long term Central Atantic wide area Water Vapor Satellite for Hurricane Season Peak flhurricane)

Long term West Atantic wide area Water Vapor Satellite for Hurricane Season Peak flhurricane)


javlin
(Weather Master)
Mon Aug 22 2011 09:42 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Well it looks that Irene made the jump over PR it kinda looked it before I hit the sack @midnight.So the E coast solution I am biting on for sure.I have one question on a piece of rumor being banted about that "I certainly think its too far west, but I did hear (last night) that the models where about 30DM too weak on the ATL ridge...So, we shall see". It looks we need some GS IV flightsout there for some upper air measurments

danielwAdministrator
(Moderator)
Mon Aug 22 2011 10:17 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 22nd day of the month at 14:04Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 302)
Storm Number & Year: 09L in 2011
Storm Name: Irene (flight in the North Atlantic basin)
Mission Number: 4
Observation Number: 07
A. Time of Center Fix: 22nd day of the month at 13:42:40Z
B. Center Fix Coordinates: 18°59'N 67°20'W (18.9833N 67.3333W)
B. Center Fix Location: 92 miles (149 km) to the WNW (295°) from San Juan, Puerto Rico (USA).
C. Minimum Height at Standard Level: 2,991m (9,813ft) at 700mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 47kts (~ 54.1mph)
E. Location of the Estimated Maximum Surface Wind: 11 nautical miles (13 statute miles) to the WSW (237°) of center fix
F. Maximum Flight Level Wind Inbound: From 326° at 46kts (From between the NW and NNW at ~ 52.9mph)
G. Location of Maximum Flight Level Wind Inbound: 11 nautical miles (13 statute miles) to the WSW (237°) of center fix
H. Minimum Sea Level Pressure: 989mb (29.21 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 9°C (48°F) at a pressure alt. of 3,050m (10,007ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 14°C (57°F) at a pressure alt. of 3,053m (10,016ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 9°C (48°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Open in the south
M. Eye Shape & Diameter: Circular with a diameter of 26 nautical miles (30 statute miles)

N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 700mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile
Remarks Section:
Maximum Wind Outbound: 73kts (~ 84.0mph) in the northeast quadrant at 13:48:30Z
Maximum Flight Level Wind: 73kts (~ 84.0mph) in the northeast quadrant at 13:48:30Z
*********************************************
Note:
This flight was at the 700mb level or 10,000 feet. The other flights were flown at 5,000 feet. There is a difference in the Eye temperatures from 5,000 to 10,000 feet. But I still see a 5 degree Celsius spread right now.
I emphasized the Eye diameter with bold above. A bit strange to see a 26 mile wide Eye in an 80 mph hurricane.

NOAA 9 or 49, the Gulfstream Jet is scheduled below:
FLIGHT THREE -- NOAA 49
A. 23/00Z
B. NOAA9 0609A IRENE
C. 22/1730Z Take Off Monday(today) at 1:30 PM EDT
F. 41,000 45,000 FT

FLIGHT FIVE -- NOAA 49
A. 23/12Z
B. NOAA9 0809A IRENE
C. 23/0530Z
D. 41,000 TO 45,000 FT


JMII
(Weather Master)
Mon Aug 22 2011 10:22 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Irene has been trending NE of its projected path, so if this continues it might stay offshore from the FL and head into GA or SC. In addition she a bit strong then originally projected which should draw her more N. She was looking really good about midday yesterday but this AM is looking more ragged, so the island disrupted her just a bit. However she was projected to be south of PR just two days ago so I'm not buying a FL landfall at this point. Historical plots also favor a more NE trend. Outflow looks good on all side except the E where a pocket of dry air still remains.

ralphfl
(Weather Master)
Mon Aug 22 2011 10:29 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

The 12z http://euler.atmos.colostate.edu/~vigh/guidance/northatlantic/track_early2.png early cycle models are out and they shifted WAY EAST i suspect the same for the main late cycle ones and a east trending plot

papaswamp
(Verified CFHC User)
Mon Aug 22 2011 10:48 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Being a complete and total newb, makes my opinion in the negative $0.02, but I have to agree with JMII…most models are tracking much further east…clips NC and heads towards NYC?

CaneTrackerInSoFl
(Storm Tracker)
Mon Aug 22 2011 10:48 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

I'm not entirely sure that she is really that far to the NE of her current projected path. If anything, it is slightly more northern. Looks like an impressive convection blowup over the COC beginning as well.

scottsvb
(Weather Master)
Mon Aug 22 2011 10:50 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Quote:

Irene has been trending NE of its projected path, so if this continues it might stay offshore from the FL and head into GA or SC. In addition she a bit strong then originally projected which should draw her more N. She was looking really good about midday yesterday but this AM is looking more ragged, so the island disrupted her just a bit. However she was projected to be south of PR just two days ago so I'm not buying a FL landfall at this point. Historical plots also favor a more NE trend. Outflow looks good on all side except the E where a pocket of dry air still remains.




I have to disagree somewhat with you in how she is.. I think she looks better than 24hrs ago..especially after going over land and small mountains of Puerto Rico. She has though always stayed 100miles NE of each Model point after 6hrs. Unless she starts showing a due W movement in the near term, Florida will be off the hook... which is 3 days out.


Marknole
(Weather Watcher)
Mon Aug 22 2011 11:02 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Yep JM. Here's what I posted yesterday morning. Trends trump averages, and Irene trended right (East) from the get-go...
Quote:

Especially if Irene strengthens, I look to see the forecasts trending down in forward speed, and moving more towards the right. Fish storm, or possibly an OBX approach.




ralphfl
(Weather Master)
Mon Aug 22 2011 11:12 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

The new forecast as i said before moved more east and shows a trend to keep doing so.Florida is more and more chances going down.

Per NHC which i said earlier:::::::: the current guidance lessens the threat
to South Florida.


Do not to focus on the exact forecast track...especially at days 4
to 5...since the most recent 5-year average errors at those
forecast times are 200 and 250 miles...respectively.


WeatherNut
(Weather Master)
Mon Aug 22 2011 11:17 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

As of now...S. FL is still in the cone of possibility. Please be prepared if you are still in the cone of uncertainty put out by the NHC. They have that cone for a reason. This looks to be a serious situation...so dont be caught off guard if you are in the cone! NHC is now forecasting a major hurricane.

danielwAdministrator
(Moderator)
Mon Aug 22 2011 11:27 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

The Florida Peninsula is still in the Cone. And using the latest NHC guidance Irene will be a Major Hurricane just south of 25N Latitude or Andros Island, Bahamas at Sunrise on Thursday Morning.

Irene is Forecast travel the entire length of the Florida Peninsula as a Category 3 Major Hurricane.
This means that almost everyone in the Cone will experience Tropical Storm Force winds for a prolonged time. As much as 24 hours.
Please take the time now and prepare a 3 Day Kit. Just in case. You can always drink the bottled water later and eat the canned goods. Don't forget the can opener. Being hungry with no can opener and lots of canned food is not a pleasant feeling.
More to follow...



scottsvb
(Weather Master)
Mon Aug 22 2011 11:46 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Florida will probably only get some squalls at most.. Still Rip Tides,Waves and beach Erosion will be the concern as people along the coast with homes will see some sort of rise in watch levels. Also Dangerous situation for Surfers as most beaches will be closed but you cant stop everyone in isolated areas going out there. Kids will be Kids.

Everyone should go out and get whatever supplies if you feel you need them. Its still 3 days out but my forecast since Friday night in the lounge is still it and probably wont change. The ridge is further NE causing a more WNW path than indictated in the models since this formed. Don't forget.. 2 days ago this was suppose to be near Haiti on the carribean side. See why we tell people to not look at models until something forms or to look past 3 days. This is really a pretty easy straight forward system to forecast.


ralphfl
(Weather Master)
Mon Aug 22 2011 11:57 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

I agree i think even with Tampa in the cone and even if the track was exact (which it won't) tampa would not get anything.Always remember the left side is the weaker side.

Also the NHC forcast is on the western side of the models so i would think come 5pm it will be even more east and maybe even the west coast of Florida out of the cone.

ALSO as the storm gets closer and a track gets more apparent the cone will shrink.I in noway am saying Florida is out of the woods but if the models do not change or the storm start going due west real fast the most Florida will see is squalls and some rain and this is South Florida east coast.

In fact Tampa would see less rain the normal no afternoon rain as all the rain would be pulled away and Tampa would be hit and dry more then normal


weathernet
(Storm Tracker)
Mon Aug 22 2011 11:58 AM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Quote:

The 12z http://euler.atmos.colostate.edu/~vigh/guidance/northatlantic/track_early2.png early cycle models are out and they shifted WAY EAST i suspect the same for the main late cycle ones and a east trending plot




I thus far have only seen the early NAM 12Z run and the beginnings of the 12Z GFS, but nothing thus far to show me further indication of how/why the "cone" was edged to the east. Could you provide another link to the early cycle models you referred to? That link seems to be broken.....


ralphfl
(Weather Master)
Mon Aug 22 2011 12:00 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

http://euler.atmos.colostate.edu/~vigh/guidance/northatlantic/track_early2.png

I posted the link earlier


scottsvb
(Weather Master)
Mon Aug 22 2011 12:08 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

You dont need to look at the NAM model..it's not for Tropical Systems.

Just watch the ECMWF and the GFS and use a blend of the 2.

GFDL has been constantly too far west but is sliding eastward each run..along
with the Ukmet..but both as not as good as the ECMWF or GFS.

It's more NE cause of the ridging I stated is depicted wrong on the models.. but looks
like the GFS has it finally correct (like ECMWF has for the past day or 2)


If you really want to know "Why" the NHC hasn't adjusted their cone more to the right
is cause it's still 3 days out and besides.. they need to keep the people informed. If they
move the cone off of florida.. people would think.. Ok.. nothing to worry about here. But
again..3 days out. They know its a good 90% chance Florida wont be more than bad
seas and surf conditions (beach erosion) but as each 12hrs gets closer.. they will move
that cone more eastward into the bahamas. .... So it's to keep peoples attention really.


ralphfl
(Weather Master)
Mon Aug 22 2011 12:10 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

http://euler.atmos.colostate.edu/~vigh/guidance/northatlantic/track_early2.png there is the link again it is working

Beach
(Weather Guru)
Mon Aug 22 2011 12:15 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Hey Scott,

How far off the coast of Cape Canaveral do you think the center will pass? 50-100miles or 100+ miles.
I am supposed to fly to New England Wednesday, and I'm trying to decide to delay the trip or not. The thought of an empty house 15 miles from the ocean as a Major goes by doesn't feel right.


scottsvb
(Weather Master)
Mon Aug 22 2011 12:19 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

My best guess right now would be it wont make it closer than 77W from where your at. Maybe 200 miles to your east. If your flying out of Orlando...you should be fine. 15 miles from the coast.. your fine.. if your on the beach.. I would be more worried about high surf and beach erosion.

Beach
(Weather Guru)
Mon Aug 22 2011 12:23 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Hey Scott thanks for that.
I found this Navy link:
http://www.nrlmry.navy.mil/htdocs_dyn_pr...ull/Latest.html
What does "CPA" mean?
It's showing Port Canaveral 82 NM
I wasn't clear on what that ment.

Thanks again


Evan Johnson
(Weather Guru)
Mon Aug 22 2011 12:25 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

keep in mind, 5 year average for errors between 4 to 5 days out are up to 250 miles either way. as far as some individuals calling fish spinners...i would just wait till we are out of the 3 day cone before i would go and do that. not to mention the shear size of this storm and the fact it might be major, consider nasty conditions regardless.

scottsvb
(Weather Master)
Mon Aug 22 2011 12:31 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Correct.. that is why part of the Cone is over parts of Florida. Keeps people paying attention in the near term. It will adjust more and more to the right.

javlin
(Weather Master)
Mon Aug 22 2011 12:32 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

the latest GFS has her making it as far N as Mass and NY?

http://raleighwx.americanwx.com/models/gfs/12zgfs500mbHGHTNA150.html


javlin
(Weather Master)
Mon Aug 22 2011 12:34 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

double post]

scottsvb
(Weather Master)
Mon Aug 22 2011 12:37 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Never look past day 3-4... It's a golden rule in the models. For example with Irene.. 2 days ago she was predicted to be south of Haiti... also GOM. It's also model trending and near term movement. Just go out to 3-4 days on the GFS and ECMWF and stay with that

weathernet
(Storm Tracker)
Mon Aug 22 2011 12:44 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

I have a concern that given the relative weak trough and fairly stout ridges ( Western Atlantic and "Texas Ridge" ), that significant deepening of Irene itself, might be adequite to potentially bridge the two ridges, thus continuing to drive her WNW into the Florida Straights or points northward to about Vero Beach.

Latest GFS certainly would seem to confirm NHC's thinking to nudge the cone farther to the east. The G-IV flight later today should confirm or perhaps "shake out" incorrect / missing synoptics that impacts the GFS runs. Tonights 0Z run might bear this out either way. I've always enjoyed a good laugh with past NHC personnel regarding the NAM ( and NGM ) being directly looked at for specific TC forecasting applications. However, as an asset to measure/forecast CONUS synoptic features ( for novice readers -Synoptic: macro-scale atmospheric processes ), it remains one of several core tools in forecasting.


Joeyfl
(Weather Guru)
Mon Aug 22 2011 12:47 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Ah another day and still quite bit of speculation where she will go long term. Latest satellite loops like like she's moving more west in the near term. I have to say even though most of the models have shifted east I would not let my guard down from Florida north to mid Atlantic. Maybe the high altitude mission tonight will put better data into models and better handle on track by tomorrow. I just would not let my guard down since this will likely be a major hurricane in couple days.

danielwAdministrator
(Moderator)
Mon Aug 22 2011 12:49 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Quote:

Hey Scott thanks for that.
I found this Navy link:
http://www.nrlmry.navy.mil/htdocs_dyn_pr...ull/Latest.html
What does "CPA" mean?
It's showing Port Canaveral 82 NM
I wasn't clear on what that ment.

Thanks again




CPA is Closest Point of Approach. Or how close the CENTER of the Storm is to the City or Naval Base listed.


Owlguin
(Weather Hobbyist)
Mon Aug 22 2011 12:50 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Agreed, looks like it is taking a jog to the west now. If that trend continues, it could have implications down the road.

ralphfl
(Weather Master)
Mon Aug 22 2011 12:53 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

SIGH again storms NEVER go in a direct line they do wobble.I was taking bets here at work when the first wobble west or south was going to come and i lost LOL.

And BTW i just looked at the last loop and fail to see what you are even talking about but we always watch the system but i do fail to see any wobble but the current motion.

Just to be 100% sire i again went back and looked at the last few radar and sat views and see no change so if you have another system of seeing this please let me know thank you very much.


Oh and again it is now again north of the NHC point which has been that way all along.


danielwAdministrator
(Moderator)
Mon Aug 22 2011 12:58 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Average Position Error (in nautical miles)

Model Name 0hr___24hr___48hr___72hr___96hr
Average____19.5__95.4___133.6___149.8__181.8 nmi

Average Intensity Error (in knots)

Model Name 0hr___24hr___48hr___72hr___96hr
Average____3.4___11.4____18.2___22.1___25.2 kts

These are as of 12Z Monday Morning.


ralphfl
(Weather Master)
Mon Aug 22 2011 01:00 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

You are correct the hnc track is 180 miles west of where the models are taking it in 3-4 days so your errors are right

berrywr
(Weather Analyst)
Mon Aug 22 2011 01:14 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

The NOAA9 flights today will be sampling the upper atmosphere ahead of Irene; specific to address what many are talking about here...the eastward change in track is good news for FL but bad news for wherever its future track is likely to be now that the core will remain over water until what that eventual landfall is. The discussion released not too long ago does mention a decrease in forward speed. Between two ridges, a longwave trough or major shortwave trough and a strong hurricane to the south what sets up is referred to as a COL; an area of weak steering currents. I did look at the 22/12Z GFS loop and Irene will be with us for a good bit; however it is where Irene will enter the westerlies and that appears to be the Mid-Atlantic. That said, there will be shifts west and east as the strengths of the two ridges need to be ascertained as we go forward as to where the trough over the east coast will be as Irene approaches. The samplings will fill in the gap in the upper air charts and provide much better resolution both for the upper air analysis that include temperature, dew point depression, wind, changes in height in decameters. This too will provide input into all models. A FL landfall was for a weaker Irene; now a projected SC/NC landfall is of a major hurricane. It is way too early to project an exact landfall now that the entire coast is in play at this time. I will post later this evening a complete analysis following the 23/00Z package release. Irene is likely to be a major hurricane.

danielwAdministrator
(Moderator)
Mon Aug 22 2011 01:32 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Here's a graphic to go with Berrywr's analysis.
The COL is a saddle shaped area between four pressure systems in this case.

High__COL__High



courtesy of CIMSS


scottsvb
(Weather Master)
Mon Aug 22 2011 01:34 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

That data going into the 0Z runs are for the current midlevel-upperlevel flow.. but when that trough digs down and breaks the ridge on Tuesday night into Weds... the midlevel flow will change... so that Mission is just for short term 24hr movement.. it's not like the ridge will be there and no trough.

Only 10% chance of this making it to florida or less... and what would give it the 10% peeps may ask? Is
that Irene moves west in the near term... hits DR around 19.5N...weakens and stays West thru Tuesday night and exposes a LLC from the midlevel causing a more run up the Cuba coastline on Weds. Again.. 10% chance.. but it's the only chance for this to come to Florida. btw... that short term jog more W has been forecasted for days and days and it never happened.. so just cause it's jogged now.. doesnt mean much cause the models still show that happening.


weathernet
(Storm Tracker)
Mon Aug 22 2011 01:46 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Quote:

Agreed, looks like it is taking a jog to the west now. If that trend continues, it could have implications down the road.




I have to agree also on the appearant short term westward motion. Tricky thing is that none of the resolutions are comfortablly able to bear out where the center might seem to be. Perhaps reforming in some of the deeper convection? No doubt that Irene's inflow is ( or likely to be ) at least somewhat impacted by Hispanola's terrain to its south/southwest. Even though the Dominican Republic's north coast is not as "inhospitable" as the very mountaineous areas farther inland, convergence would seem to be impacted. Now, "if" Irene is truly trending westward in the short term and interacts with the island to a larger degree, well then Irene's general intensity, forward motion, etc. need be taken somewhat into consideration as it might apply to later 3-5 day forecast points.

My original thoughs days ago, were that Irene would pass to the north of HIspanola ( maybe scraping the NE coast at most ), however at the moment looks poised to possibly get tangled up there. Don't know whats worse, flooding rains and mudslides impacting many in D.R. as well as many impoverished in Haiti, or the prospects of a possible Cat. 4 making a slow motion landfall up in S. Carolina? Lets hope its neither...

Interesting note, though a very different looking ( and much weaker ) storm, didn't the center fix of Emily more or less make it ( and was well forecasted by NHC ) to just go east of Andros Island in the Bahamas as well? Looks a little like a pattern trying to set up for the season.


MikeCAdministrator
(Admin)
Mon Aug 22 2011 01:47 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Looking at the satellite loops, it seems there is something going on between the low level circulation and the mid levels, either it's struggling a bit or it may be attempting to separate or reform again. Recon is out there finding 988 mb pressure readings though. Irene still isn't well defined near the center, even as a hurricane (relatively, it still is pretty strong), with most of the convection to the north side of the center.

Hispaniola has had a history of odd affects on tropical cyclones (other than just weakening), and it may be related to that. Track/intensity are going to be a bit more up in the air until it clears Hispaniola. Still the eastern trend is the most solid thing right now.


LoisCane
(Veteran Storm Chaser)
Mon Aug 22 2011 01:54 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

It's important not to focus on the 4 and 5 day forecast right now as said earlier the margin of error is very a few hundred miles. The margin of error on the 3 day cone is excellent. Everyone from South Florida to Long Island is beginning to obsess on the point of landfall five days away. That is normal.

It's important to remember what the NHC says and that is to focus on the cone not the line. It's hard to do but it's imperative. If you are in the far right or left part of the Cone the NHC feels it could be there in 4 or 5 days. Time and time again the small shifts in a cone every six hours equates to a large spread down the road.

Many factors will affect this storm.. every "jog" west or east will influence the next track. The important point if you live in the Carolinas or Florida or beyond is to keep watching. For the people in the islands now or in the Bahamas this is a serious problem now...

Also, how much interaction she has with DR may have an effect on her as for speed of forward motion as well as intensity.

http://www.ssd.noaa.gov/goes/east/tatl/flash-wv.html

A lot of factors will affect this storm, most far to the north of her.


weathernet
(Storm Tracker)
Mon Aug 22 2011 02:13 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Silly GFDL, don't you know you're not "on-board" with the Euro/GFS Globals?

Here's the latest 12Z GFDL ( 90 hr. ) showing a 921mb over MIami ( Am pretty sure either the following 102 hr. or perhaps was the 114 hr, had Irene remaining intense over Lake Okachobee ).

http://raleighwx.americanwx.com/models/gfdl/12zgfdl2500mbHGHTPMSL090.gif


scottsvb
(Weather Master)
Mon Aug 22 2011 02:15 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

It's still slightly more east. Would need a land interaction with DR for that to have a slight chance of happening. Otherewise a jump west by ECMWF and followed by the GFS.

ralphfl
(Weather Master)
Mon Aug 22 2011 02:19 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

With the 12z UKMET AND THE 12Z GFDL the 2 outliners moving way east towards the gfs and euro i can see them moving it a little more east again at 5pm about as much as they did at 11am which i think would take Florida west coast out of the cone if that happens.

The bottom line is you watch it and keep tabs of what it is doing and the trends and right now the trend continues to be east.

At least for now it is still 80mph and hopefully does not make cat 3 or 4 because a cat 3-4 storm would be up in SC/NC or even up more.


Wanna-Be-Storm-Chaser
(Weather Hobbyist)
Mon Aug 22 2011 02:41 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

So are you saying the GFDL is off? I thought they were the most reliable ones.

scottsvb
(Weather Master)
Mon Aug 22 2011 02:43 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

GFDL is the 3rd best model .(IMO) Just it's been to far off to the left the whole time and been moving east.

MikeCAdministrator
(Admin)
Mon Aug 22 2011 02:45 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Quote:

So are you saying the GFDL is off? I thought they were the most reliable ones.




The euro has been the most accurate this year, and the GFDL has been less so, but it did ok for Emily, if you look at "Maps and Coordinates" on the left, you can see the model plots back to 2005 to compare.

Right now the GFDL is the outlier, but it is still within the NHC's cone. The Euro has been doing better this year so far, and for Irene it's more easterly toward Wilmington, SC. The short range forecasts out to 2 days are probably really where you want to see the trends at.

In truth each model has its strengths and weaknesses and depending on the overall setup some do better than others. The GFDL may be picking up something the others are missing, but that usually washes out (By being too far west), and you wind up with something like the NHC's forecast, which all said and done, looks pretty good.


Wanna-Be-Storm-Chaser
(Weather Hobbyist)
Mon Aug 22 2011 03:07 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

The GFDL is just so far off from the others and I thought they are accurate. Thanks. I am just concerned the ridge might stay put and not shift her NW when they say it will. Will just keep watching!

LoisCane
(Veteran Storm Chaser)
Mon Aug 22 2011 03:13 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

The GFDL model also has it as a very intense storm. It's very possible it's seeing the effect of an Intense Major and it's making it's on steering currents. Often there is a momentum factor with strong Major storms that take longer to move or curve. That's one of the only things I can think of other than it obviously sees a stronger high.

The GFDL would create a massive storm surge scenario that Miami has not seen since the 1926 Great Miami Hurricane.

Despite how reliable it is a model, all the others don't see what it sees.

Emily's track was perfect, she just didn't intensify and stay together if I remember.

What else the GFDL sees I don't know but it's hard to ignore.


scottsvb
(Weather Master)
Mon Aug 22 2011 03:18 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

GFDL has been wrong from the start... but anyways... I expect IRENE to really develop tonight into a CAT 2 or maybe CAT 3 by 11am Tuesday (as long as she stays far enough away from DR. Pressure should really drop tonight into Tuesday morning as everything is in almost perfect set up to do so. (Yes and Im usually the cautious Met).. lol

MikeCAdministrator
(Admin)
Mon Aug 22 2011 03:24 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

There is a coordinated effort tonight to collect tons of upper air data, as a lot of the NWS weather stations will be releasing extra weather balloons and the Gulfstream IV jet will be taking samples of the upper air. So tomorrow's model runs should have a lot better data collection, and hopefully the eastern trend will hold.

As far as the GFDL is concerned, I'm discounting it until more data is available.


GuppieGrouper
(Weather Master)
Mon Aug 22 2011 04:10 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Referring to the map of ridges and troughs that appeared and Berrywr spoke about. I thought I noticed a similar set up in the way that Jeanne or Frances hovered in that same general area for a few days and still crossed central/south Florida as a major hurricane when all was said and done. I know that the scenarios are not exactly alike, but this did strike me as being one of those long range conditions that the models are not addressing yet.

MikeCAdministrator
(Admin)
Mon Aug 22 2011 04:19 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

You are probably referring to Advisory 29 of Hurricane Frances. Stacey Stewart goes into detail with the forecast discussion why the Gulfstream IV jet data was so important at that time to determine the strength of the ridging and movement of that storm. Until that detail is cleared up, the GFDL is an outlier. But to be honest, I don't expect them to find anything too far from what we already know. However, the NHC is putting extra effort into collecting data, so there is some legitimate question about the ridging.

weathernet
(Storm Tracker)
Mon Aug 22 2011 04:22 PM
Re: Irene the Year's first Hurricane, Passes Over Puerto Rico

Mike, are we pretty sure that all the latest data will be ingested in time, so to show up in the 0Z runs this evening?

There is no question that the Euro and GFS Global models perhaps provide the most accurate forecasts. I perhaps find that the GFS "sniffs out" potenial development faster than the more conservative Euro does. That said, once latched on I would perhaps test to slightly favor the Euro model. As amazing as the GFS has been in consistantly forecasting development and general motion....it AND every other model that I can think of INCORRECTLY depicted Irene to go south of Puerto Rico and either direclly over Hispanola and Eastern Cuba, or others even farther south. Ultimately, each of the various models out perform the others given certain circumstance and conditions relating to so many factors ( lower latitudes vs. higher latitudes, size & strength of the system, or their ability to better mesh forecasted motion and development verses interaction with TUTT's, Cut-Off Low's, Troughs, Ridges, etc. ). Even the LBAR has a purpose ( though if my life depended on it, I could not tell you what that might be

I think those who might indicate that one or two models clearly present "the solution", and too disregard any other reasoning, would not only imply a degree of ignorance but furthermore understates the very difficult job NHC forecasters really have ( well beyond any political/psychological media releases to keep the masses from panicking ). The key with the many models, are to have the knowledge to know their strengths and weaknesses, and to make the human decision how much weight to apply to them based upon each unique situation.


Yhegler35
(Registered User)
Mon Aug 22 2011 04:38 PM
Re: Hurricane Warnings up for the Bahamas from Irene

What are the odds the GFDL is correct and Irene will hit Florida?

MikeCAdministrator
(Admin)
Mon Aug 22 2011 04:40 PM
Re: Hurricane Warnings up for the Bahamas from Irene

Quote:

What are the odds the GFDL is correct and Irene will hit Florida?




About 5%, see here

not 100% sure on if the special sounding data will make it for the 0z runs, but it's likely. I'll try to find out, by 6 or 12Z for sure though. Some of the 18Zs coming out may have partial data from it. The data it's collecting (along with the other special soundings) is extremely important with this environmental setup in determining the future track of Irene. There is the NOAA jet, and an airforce plane also doing upper air soundings up right now over the area north and west of Irene. The NHC is taking them very seriously.

Irene's center (Aka central dense overcast) is very symmetrical right now, and the best it's ever looked. South side of the storm is still rugged looking though and probably will remain so until it gets away from Hispaniola. North side is looking very good, although some elongation west to east.





MikeCAdministrator
(Admin)
Mon Aug 22 2011 04:58 PM
Re: Hurricane Warnings up for the Bahamas from Irene

5PM Forecast is out, the offical track was kept pretty much as was (just shifted 12 hours ahead). Basically, the odds are trending away from Florida, but increasing for coastal Carolinas.

I would not expect any track changes until the dropsonde and weather balloon data is put into the various models.



danielwAdministrator
(Moderator)
Mon Aug 22 2011 05:17 PM
Re: Hurricane Warnings up for the Bahamas from Irene

0730Z MON AUG 22 2011

THE NATIONAL HURRICANE CENTER IS REQUESTING SPECIAL 6-HOURLY UPPER
AIR RELEASES BEGINNING AT 18Z TODAY (MON AUG 22) FROM THE
FOLLOWING STATIONS: KEY WEST, MIAMI, TAMPA, JACKSONVILLE,
TALLAHASSEE, SLIDELL, JACKSON, BIRMINGHAM, PEACHTREE CITY,
CHARLESTON, MOREHEAD CITY, GREENSBORO, NASHVILLE, WILMINGTON,
PITTSBURGH, BLACKSBURG, STERLING AND WALLOPS ISLAND.

THE 12Z NAM MODEL HAS STARTED ON-TIME WITH GOOD UPR AIR COVERAGE
INCLUDING 14 ALASKAN...31 CANADIAN...73 CONUS...10 MEXICAN AND 10
CARIBBEAN REPORTS...AS WELL AS ONE DROPSONDE REPORT AND 3 FLIGHT
LEVEL RECON REPORTS.

All of this is extra data from today. For input into the various weather models. I assume the 3 flight level Recon reports were the three Vortex reports. I hate to assume. Circumstantial evidence.


vineyardsaker
(Weather Guru)
Mon Aug 22 2011 06:16 PM
Re: Hurricane Warnings up for the Bahamas from Irene

Assuming the NHC track stays pretty much what it is now, what kind of storm surge does East Central FL risk?

weathernet
(Storm Tracker)
Mon Aug 22 2011 06:25 PM
Re: Hurricane Warnings up for the Bahamas from Irene

Just took a look at the updated 18Z runs of the GFS and NAM. "Ditto" with regards to the NAM, while variances with the 18Z as compared to the 12Z are minimal. Perhaps up to about 60 hr., the slightest bit faster and perhaps 30-40 miles westward, then nearly identical NNW motion though seemingly a little slower motion once passing Miami's latitude. Ultimately the variance is negligable. I had understood ( from a different forum ), that approx. 1/3 of the dropsondes had been conducted and which data was injected into the 18Z run. My understanding was however, that basically all of the dropsondes were to have been conducted and the data to be ingested in time for the 0Z runs this evening.

Random Chaos
(Weather Analyst)
Mon Aug 22 2011 06:25 PM
Re: Hurricane Warnings up for the Bahamas from Irene

Irene is a huge system, and will take time to consolidate, and thus strengthen. The CDO appears to be completely missing Hispanola, which is not good for us in the US since it means the interaction with the mountains will be minimal. It also means it is further north, and thus right of track. Based on IR history, I would say this is more likely a wobble due to the land interaction with Puerto Rico than an actual track shift, but that is not guarenteed.

Using the outermost feederbands, the storm is 700 miles across, though the center is very much toward the southwest of that total cloud mass. As the system deepens and spins up, the storm will shed the outer cloud bands and consolidate toward the core, an area I estimate to be around 100-125 miles in radius (200-250 miles in diameter), which makes it around the size of some of the larger diameter storms that occur in the Atlantic. This will slow it's strengthening (the shear size of it makes it more difficult for it to organize), but the SSTs are hot and very conducive to strengthening, so it might take less time than most storms would.

Keep an eye on the storm if you are anywhere from Florida through New England. Even if the storm misses landfall, we could have a major beach erosion issue for the entire Atlantic seaboard. Right now it looks like the gulf is out of the threat cone, but hurricanes can be erratic, and long range forecasts often change as the storm draws closer.

Edit: Spectacular animation showing Irene developing:
http://www.nasa.gov/mission_pages/hurricanes/archives/2011/h2011_irene.html


Sheeper
(Weather Hobbyist)
Mon Aug 22 2011 07:11 PM
Re: Hurricane Warnings up for the Bahamas from Irene

There is a LOT of uncertainty on the track. Our FEMA IMT just got put on deployment standby for "somewhere" on the east coast. No idea where I or Irene will end up!

MikeCAdministrator
(Admin)
Mon Aug 22 2011 07:35 PM
Re: Hurricane Warnings up for the Bahamas from Irene

I'm updating the 18z model rundown in the lounge, seems like a slight shift west in this run, some of the gulfstream IV data is in there now, but most of it won't show up until the 0z models later.

Recon is finding winds closer to 95-100 mph.


danielwAdministrator
(Moderator)
Mon Aug 22 2011 07:40 PM
Re: Hurricane Warnings up for the Bahamas from Irene

Quote:

There is a LOT of uncertainty on the track. Our FEMA IMT just got put on deployment standby for "somewhere" on the east coast. No idea where I or Irene will end up!


.

Based on the latest model that could be anywhere from Key West,FL to Cape Cod,Massachusetts.
I'm sure that most of the Eastern FEMA and USAR Teams are being alerted. Or will be in the morning. Odds are the FL and SE Teams will go first and the others will be a wait and see.


danielwAdministrator
(Moderator)
Mon Aug 22 2011 07:51 PM
Re: Hurricane Warnings up for the Bahamas from Irene

URNT12 KNHC 222335
VORTEX DATA MESSAGE AL092011
A. 22/23:25:00Z
B. 19 deg 41 min N
068 deg 39 min W
C. 850 mb 1278 m
D. 41 kt
E. 145 deg 88 nm
F. 240 deg 56 kt
G. 171 deg 10 nm
H. 982 mb
I. 18 C / 1521 m
J. 23 C / 1517 m
K. 20 C / NA
L. OPEN SE-SW
M. E31/30/24 Elliptical eye, major axis 310-130, length of major axis 30 NM, length
of minor axis 24NM
N. 12345 / 8
O. 0.02 / 3 nm
P. AF303 0709A IRENE OB 04
MAX FL WIND 56 KT S QUAD 23:21:50Z
MAX FL TEMP 24 C 175 / 8 NM FROM FL CNTR


danielwAdministrator
(Moderator)
Mon Aug 22 2011 07:54 PM
Re: Hurricane Warnings up for the Bahamas from Irene

The Weather Channel is reporting an upgrade to Category 2 on the Saffir-Simpson Hurricane Scale.
Wind speeds have increased to 100 mph. I'm looking for the update now.

HURRICANE IRENE TROPICAL CYCLONE UPDATE
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
750 PM AST MON AUG 22 2011

...IRENE NOW A CATEGORY TWO HURRICANE...

REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
THAT IRENE HAS STRENGTHENED...AND IS NOW A CATEGORY TWO HURRICANE
WITH MAXIMUM SUSTAINED WINDS OF 100 MPH...155 KM/H. DETAILS WILL
FOLLOW IN A SPECIAL ADVISORY TO BE ISSUED BY 815 PM AST...0015 UTC.


SUMMARY OF 750 PM AST...2350 UTC...INFORMATION
--------------------------------------------------
LOCATION...19.7N 68.7W
ABOUT 200 MI...320 KM SE OF GRAND TURK ISLAND
ABOUT 130 MI...210 KM E OF PUERTO PLATA DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...981 MB...28.97 INCHES


ralphfl
(Weather Master)
Mon Aug 22 2011 08:00 PM
Re: Hurricane Warnings up for the Bahamas from Irene

THE 18Z GFDL IS STILL MOVING MORE AND MORE EAST.THIS RUN IT HAS MOVED ANOTHER SHIFT TO THE EAST maybe sooner or later they will all meet somewhere but it has now 3 runs in a row moved east.

danielwAdministrator
(Moderator)
Mon Aug 22 2011 08:31 PM
Category Two Irene

I'm still waiting on the hard copy. The Weather Channel is reporting that the NHC Forecast has increased the Forecast Wind Speed to 125 mph in the area of the Bahamas.

This would make Irene a Category 4 Major hurricane near and over the Bahamas.
Irene was previously forecast to pass through the Bahamas as a Category 3 Major Hurricane.

HURRICANE IRENE SPECIAL DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
830 PM AST MON AUG 22 2011

THE HURRICANE HUNTER AIRCRAFT FOUND A 850-MB FLIGHT LEVEL WIND
MAXIMUM OF 106 KT ON ITS FIRST PASS THROUGH THE CENTER OF IRENE.
BASED ON THIS...THE INITIAL INTENSITY IS ADJUSTED UPWARD TO 85 KT.
OVER THE PAST COUPLE OF HOURS THE SATELLITE PRESENTATION OF THE
HURRICANE HAS CONTINUED TO IMPROVE...ALTHOUGH NO EYE IS VISIBLE YET
IN GEOSTATIONARY IMAGERY. HOWEVER...AN EYE HAS BECOME APPARENT ON
THE SAN JUAN DOPPLER RADAR AND WAS ALSO SEEN IN A 2230 UTC SSMIS
PASS. THE CENTRAL PRESSURE HAS FALLEN TO 981 MB BASED ON A
DROPSONDE OBSERVATION OF 982 MB WITH 10 KT OF WIND AT THE SURFACE.
GIVEN THAT THE ENVIRONMENT APPEARS CONDUCIVE FOR ADDITIONAL
STRENGTHENING...THE INTENSITY FORECAST HAS BEEN ADJUSTED UPWARD BY
15 KT THROUGH 36 HOURS WITH A SMALLER UPWARD ADJUSTMENT AT 48 AND
72 HOURS. ONLY SLIGHT WEAKENING IS INDICATED AT DAYS 4 AND 5. THE
NEW FORECAST NOW SHOWS IRENE BECOMING A MAJOR HURRICANE ON TUESDAY
AS IT MOVES THROUGH THE SOUTHEASTERN BAHAMAS AND THE TURKS AND
CAICOS ISLANDS. THE WIND RADII HAVE BEEN EXPANDED BASED ON AIRCRAFT
DATA AND THE NEW INTENSITY FORECAST.

NO CHANGES HAVE BEEN MADE TO THE TRACK FORECAST ON THIS SPECIAL
ADVISORY.

FORECAST POSITIONS AND MAX WINDS

INIT 23/0030Z 19.7N 68.7W 85 KT 100 MPH
12H 23/0600Z 20.1N 70.2W 95 KT 110 MPH
24H 23/1800Z 20.8N 72.5W 105 KT 120 MPH
36H 24/0600Z 21.5N 74.0W 110 KT 125 MPH
48H 24/1800Z 23.0N 75.5W 110 KT 125 MPH
72H 25/1800Z 26.0N 78.0W 110 KT 125 MPH
96H 26/1800Z 29.5N 79.0W 105 KT 120 MPH
120H 27/1800Z 34.0N 79.0W 95 KT 110 MPH...INLAND


Random Chaos
(Weather Analyst)
Mon Aug 22 2011 08:40 PM
Re: Category Two Irene

Watching the AVN loop, not sure I've seen this much intense convection in the CDO since Wilma was undergoing rapid intensification. This is one storm to keep a very close eye on.

The SSTs are not just warm, they are hot, right now, with most of the region it will be passing over between 29C and 31C. Nothing atmospherically appears to be going to weaken her in the near term.

SSTs:
http://www7320.nrlssc.navy.mil/hhc/watl/sst2.watl.20110720.gif

SST HHP:
http://www7320.nrlssc.navy.mil/hhc/watl/hh3.watl.20110720.gif

Main SST site:
http://www7320.nrlssc.navy.mil/hhc/all_watl.html

Edit: SST site was down, not gone, when I last checked. It's back.


Lamar-Plant City
(Storm Tracker)
Mon Aug 22 2011 08:42 PM
Re: Category Two Irene

This is the one I go to. They buried it on the site a bit but I think it is what you are looking for.

LSU Earthscan labs weekly composite sea surface temps


danielwAdministrator
(Moderator)
Mon Aug 22 2011 08:49 PM
Re: Category Two Irene

Jim Cantore on the Weather Channel had nearly the same comment.
He was discussing the coldest color semicircle surrounding the Eye. He said he didn't recall ever seeing that color.

The area he referred to is the reddish-white area in the CDO. He also asked Brian Norcross when was the last time he had seen a 100 mph Hurricane without a visible Eye.
Also notice the convection on the South side of the Dominican Republic. Cloud tops there are nearly as high as the cloud tops near the Eye. 100 miles away.



LoisCane
(Veteran Storm Chaser)
Mon Aug 22 2011 08:52 PM
Re: Category Two Irene

So my question for the night after the stunning development of her rapid intensification to Category 2 status is:

Which models predicated that because they would be the ones I'd give more attention to...

Rarely do you see a storm intensify while it is partially over land and she looks better now than she did a few hours ago.

There is a big difference between a Category 2 in the Bahamas and a Category 3 and am wondering if those models that showed her being a Category 4 (GFDL for one, but I think there was another) might not be totally off.

The power of a hurricane, a major hurricane, is a humbling thing and in itself it can often change the environmental factors driving it. She has a lot of warm, very warm water to run across and am seriously obsessing too much on how strong she can be in the Bahamas.

No matter who gets her up the line... this is going to be a dangerous storm for Nassau...


Joeyfl
(Weather Guru)
Mon Aug 22 2011 08:57 PM
Re: Category Two Irene

Slight shift west in 0z guidance will have to wait to see if others follow suite tonight, I really hope everyone from FL and north is paying attention shes gaining strength quickly.

danielwAdministrator
(Moderator)
Mon Aug 22 2011 09:00 PM
Re: Category Two Irene

The last two SHIPS models, that I saw earlier today, had a 44% chance for a 25 knot increase.
I need to look at the 00Z run.

00Z run looks like it was run prior to the 100 mph wind speed report. It's still showing a 25% chance of a 25 kt increase.


Random Chaos
(Weather Analyst)
Mon Aug 22 2011 09:04 PM
Re: Category Two Irene

In reference to the last time a 100mph hurricane without a visible eye. Going by Dvorak guidance, the storm should be at least a T5.0 per the intensity chart, however an eye becomes visible at T4.5; SSD is indicating the storm was T4.5 last update while CMISS ADT was showing a T4.2 based on computer analysis of the CDO.

This storm is very unusual. I think essentially it is strengthening too rapidly for the eye to have cleared out yet, but it is actually a higher T number.

CMISS ADT ref: http://tropic.ssec.wisc.edu/real-time/adt/odt09L.html


CaneTrackerInSoFl
(Storm Tracker)
Mon Aug 22 2011 09:12 PM
Re: Category Two Irene

The last time I can recall that large amount of deep convection was (and I hate to say it for pure karmic reasons) but Wilma. Now, Wilma was a special case but I haven't seen that deep of convection out of an Atlantic storm in a while.

MikeCAdministrator
(Admin)
Mon Aug 22 2011 09:15 PM
Re: Category Two Irene

The newest recon fix has found 107knot winds at flight level, with the 90% rule for 700mb applied takes it to 105-110mph winds. Pressure still at 981 though.

danielwAdministrator
(Moderator)
Mon Aug 22 2011 09:20 PM
Re: Category Two Irene

URNT12 KNHC 230109 CCA
VORTEX DATA MESSAGE AL092011
A. 23/00:49:00Z
B. 19 deg 49 min N
068 deg 51 min W
C. 700 mb 2944 m
D. 71 kt
E. 269 deg 92 nm
F. 329 deg 60 kt
G. 259 deg 15 nm
H. 981 mb
I. 11 C / 3047 m
J. 17 C / 3050 m
K. NA / NA
L. CLOSED WALL
M. C30 Circular 30 nm Closed EYE.....

N. 12345 / 7
O. 0.02 / 3 nm
P. AF303 0709A IRENE OB 08 CCA
MAX FL WIND 107 KT NW QUAD 23:30:20Z
MAX FL TEMP 17 C 266 / 7 NM FROM FL CNTR

Good data Mike. Quick rule for the 700mb flight level winds. Take the flight level wind max in knots. In this case 107 knots.
Change the knots to mph and that's a really close estimate without the math of the Surface Wind speed.

107 kt- kt+mph = 107 mph surface wind.


MikeCAdministrator
(Admin)
Mon Aug 22 2011 09:35 PM
Re: Category Two Irene

The nrl link for Irene's Microwave Imagery shows the circular eyewall. It will probably become visible on the IR satellite in a few hours.



k___g
(Weather Guru)
Mon Aug 22 2011 10:13 PM
Re: Category Two Irene

As long as she continues to decrease forward speed the better chance that she will follow the upcoming weakness between the ridges.

MikeCAdministrator
(Admin)
Mon Aug 22 2011 10:51 PM
Re: Category Two Irene

It appears that the big blowup got interrupted by Hispaniola, it's still a very healthy hurricane, but the boom from earlier has halted, for now.

danielwAdministrator
(Moderator)
Mon Aug 22 2011 10:54 PM
Re: Category Two Irene

URNT12 KNHC 230251
VORTEX DATA MESSAGE AL092011
A. 23/02:38:20Z
B. 19 deg 51 min N
069 deg 11 min W
C. 700 mb 2954 m
D. 71 kt
E. 307 deg 11 nm
F. 048 deg 69 kt
G. 310 deg 16 nm
H. 983 mb
I. 12 C / 3046 m
J. 16 C / 3053 m
K. NA / NA
L. OPEN E-SE
M. C14
N. 12345 / 7
O. 0.02 / 1 nm
P. AF303 0709A IRENE OB 12
MAX FL WIND 77 KT NE QUAD 00:53:30Z
MAX OUTBOUND FL WIND 71 KT SE QUAD 02:43:00Z
MAX FL TEMP 17 C 307 / 8 NM FROM FL CNTR


MikeCAdministrator
(Admin)
Mon Aug 22 2011 11:01 PM
Re: Category Two Irene

The 11PM official track is out.

There is no real change to the forecast, it is just further along on the points in time, nor changes to watches and warnings.

It appears that the hurricane center is waiting for the next model runs with the Gultstream and Air Force dropsonde data to make any real change, which seems wise.

The Intensity forecast is up in the near term, now a cat 4 projected over the Bahamas, then it weakens to cat 3 north, and eventually approaches the NC/SC border Saturday evening.

If tropical storm or hurricane watches were to go up for Irene in Florida, they would likely come sometime tomorrow afternoon to fit in the 48.watch window.


Random Chaos
(Weather Analyst)
Mon Aug 22 2011 11:02 PM
Re: Category Two Irene

NHC intensity forecast:

INIT 23/0300Z 19.9N 69.2W 85 KT 100 MPH
12H 23/1200Z 20.4N 70.6W 95 KT 110 MPH
24H 24/0000Z 21.1N 72.4W 105 KT 120 MPH
36H 24/1200Z 22.2N 74.2W 110 KT 125 MPH
48H 25/0000Z 23.5N 75.6W 110 KT 125 MPH
72H 26/0000Z 26.5N 78.0W 115 KT 135 MPH
96H 27/0000Z 30.0N 79.0W 105 KT 120 MPH
120H 28/0000Z 33.5N 78.5W 100 KT 115 MPH


danielwAdministrator
(Moderator)
Mon Aug 22 2011 11:06 PM
Re: Category Two Irene

Quote:

NHC intensity forecast:

72H 26/0000Z 26.5N 78.0W 115 KT 135 MPH





That position is on the East End of Grand Bahama Island. And 80 miles east of West Palm Beach.
Worst of all it's at Sunset. 00Z


danielwAdministrator
(Moderator)
Mon Aug 22 2011 11:23 PM
Re: Category Two Irene

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS CAMP SPRINGS MD
0315Z TUE AUG 23 2011

THE 00Z GFS MODEL IS RUNNING ON TIME. RAWINSONDE COVERAGE FOR
MODEL DATA ASSIMILATION WAS EXCELLENT ACROSS NORTH AMERICA AND
INCLUDED 36 DROPSONDES FROM OVER THE CARIBBEAN SEA AND SOUTHWEST
ATLANTIC OCEAN.

36 extra points of data. Wow! That ought to boost the models.


GuppieGrouper
(Weather Master)
Mon Aug 22 2011 11:27 PM
Re: Category Two Irene

When will the data be available to the public and of course here on the Board? I mean will we see it in the morning or tomorrow night etc.?

danielwAdministrator
(Moderator)
Mon Aug 22 2011 11:37 PM
Re: Category Two Irene

The data should help the models determine what is going on in the atmosphere surrounding Irene.
The only way we will see any effect of the data is for the models to converge more than they are currently.
However, lack of convergence doesn't imply the data was bad. It just reenforces the models being more correct.

In short. The data should improve the clustering of the model tracks. It won't change the size of the Cone. But it could change the location of the Cone. East or West.

Berrywr posted earlier in the Forecast Lounge that the Ridge near Bermuda had actually increased somewhat over a 12 hour span. In part due to Irene's outflow.

That's above my head. (No pun intended)
But my guess is that the outflow has moistened the atmosphere and changed the heights.
Or the outflow pumped the moisture out of the air at one level and increased it at another level.


mwillis
(Weather Hobbyist)
Mon Aug 22 2011 11:37 PM
Re: Category Two Irene

at 02:45 UTC on water vaper you can see an eye starting to form, or is formed. Doesnt that look like a small eye for a large system?
http://www.ssd.noaa.gov/goes/flt/t2/wv-l.jpg

eye is at 69 west line


berrywr
(Weather Analyst)
Mon Aug 22 2011 11:41 PM
23/00Z Upper Air Package & Irene

I've analyzed the 500mb Upper Air Analysis with Plots and as many here have posted concern continues with whether Irene will turn north before becoming a real threat to FL or as some models continue to suggest a more westward track. This evening upper air data from Bermuda indicated a 10 meter increase to 594 decameters which continues to suggest the Bermuda subtropical ridge remains strong. A re-analyzing of the Mid-Continental "Texas" upper ridge continues to be entrenched over drought-stricken Texas. The east coast longwave trough lies between the two and is progressive however based on 20 meter height falls I've re-drawn the bottom of the trough to be across the northern FL where it ends near the upper ridge axis along 29N latitude. There remains a break in the ridge along a north-south axis near 27N 72W. NOAA9 extensively sampled the entire envelope ahead of Irene. The COL is centered once again near 27N 72W. It was noted on the 22/09Z NHC discussion that if Irene reaches major hurricane status and with such a large circulation that outflow entering the westerlies to the north will also aid in keeping the upper ridge to the east strong again suggesting a closer approach to FL. New data this evening suggests this remains plausible. Intensity forecasting is problematic but Irene will be a major hurricane soon.


Larger version of image


LoisCane
(Veteran Storm Chaser)
Tue Aug 23 2011 12:11 AM
Re: 23/00Z Upper Air Package & Irene

Okay so how similar to this set up was Floyd. Thanks for the analysis, and the effort you put in.

I'm concerned about some of the discussion which seemed to leave a wide door for variations in track over the next few days.

A category four storm off shore Miami by 100 .. 120 miles is really too close for comfort. Looking forward to the new model runs with the info from the Gulfstream Jet.


ralphfl
(Weather Master)
Tue Aug 23 2011 12:34 AM
Re: 23/00Z Upper Air Package & Irene

Well if the GFS is any help with the new info it has shifted more east and northeast.in the new run.

With landfall in morehead city NC...

So the GFS has shifted again EAST and a more north movement before landfall.


Random Chaos
(Weather Analyst)
Tue Aug 23 2011 12:38 AM
Re: 23/00Z Upper Air Package & Irene

Both dropsonde and flightlevel winds indicate the storm has weakened a little. Probably only about 85 to 90mph right now. Eyewall dropsonde showed 53kts at surface but may have missed the strongest wind. The eyewall is open southeast. Vortex recon report indicated the strongest winds at altitude were 83kt (95.55 MPH), which translates less at the surface. Given that it might have missed the strongest winds again, I'm giving an upper bound of 90mph surface.

However, pressure is down 3mb and IR shows the center reforming at the moment. My thought is this wind drop is transitory and she will be back to definite Category 2 shortly. Looks like there was some disruption of the southern feeders by the mountains of Hispanola which is being worked out of the system now. Once that is done, no reason for it not to strengthen again.


WeatherNut
(Weather Master)
Tue Aug 23 2011 12:52 AM
Re: 23/00Z Upper Air Package & Irene

At some point there will also be Eyewall Replacement Cycles. As mentioned earlier, the eye is rather small which is usually a sign that an ERC will be coming on at some point. No one really can forecast these until they are happening

scottsvb
(Weather Master)
Tue Aug 23 2011 01:28 AM
Re: 23/00Z Upper Air Package & Irene

I really don't see much of a change with the dropsonde package. Never really changes a models output..maybe just slightly in the near term cause its always changing. That's why there is a mission again on Tues,Weds,Thurs..etc etc... with a trough digging in eroding the ridge, it wont matter how much heat gets pulled up into the ridge. Intense hurricanes like 950mb or lower has like 2% worth or less impact on the ridge or trough that approaches.

GFS 00Z run has actually again shifted back east to its 12Z run.

Main near term factor is the Failed pattern of the ridge over the past 3 days. GFS has finally come inline with this ridge as of the 12Z run today and 0Z run by showing a more WNW movement (that it has had since Saturday). Others continued with a more W-WNW motion of 280dg except the HWRF but that model is usually on the right side of most runs.
Medium range will have the Cat3-4 Hurricane actually helping dig the trough on its western side pulling the Hurricane N and NE.. too early to say if there will be a landfall in the Carolinas.. SC-NC will get Tropical Storm conditions at least. Florida has a 5% chance of making a landfall or less even as I stated last Friday night.

Overall this is a typical run the coast between the US-Bermuda storm but is closer than normal due to it developing just east of the islands instead of east of 55W. Remember the GFS didnt have this develop until Sat night in the SE carribean around 14-15N and 62-64W.. but this developed further north around 17N and 58W. Also ridging was more NE causing a WNW movement instead of the movement just north of due west that most models showed for Sunday-Tuesday.

In all....we have a Cat 2 that should be a Cat 3 on Tuesday and Cat 4 possibly over the next day or 2. Pretty much a straight shot into the bahamas and moving just east of Nassau in 3 days or less. Also note after the first short wave passes.. there is no ridging behind this short wave... so the strength of the ridge to the east of Irene will pull whatever is west of it N until the next short wave comes by this weekend into next week. But this isnt a forecast cause that is more than 4 days from now.



Note: This is NOT an official page. It is run by weather hobbyists and should not be used as a replacement for official sources. 
CFHC's main servers are currently located at Hostdime.com in Orlando, FL.
Image Server Network thanks to Mike Potts and Amazon Web Services. If you have static file hosting space that allows dns aliasing contact us to help out! Some Maps Provided by:
Great thanks to all who donated and everyone who uses the site as well. Site designed for 800x600+ resolution
When in doubt, take the word of the National Hurricane Center