MikeCAdministrator
(Admin)
Tue Sep 29 2015 11:14 AM
Joaquin Heading Northeast, Back to Cat 4

1PM EDT Update 3 October 2015
Recon has found Joaquin now has 155MPH winds. Hurricane Watch up for Bermuda may be upgraded later today to a warning.
-Ciel


1030 AM EDT Update 3 October 2015
Joaquin is finally moving away from the Bahamas, and the storm seems to be regaining strength this morning. The eye is more visible now than any time prior. Although it is moving generally out to sea, Bermuda has tropical storm warnings and a hurricane watch up since it may get very close and still be very powerful then.

Moisture is also streaming off the westward side enhancing the huge rainfall in the Carolinas and a bit northward.

based on recon, it's now a cat 4, and is actually a bit stronger than the 11AM advisory states.



1PM EDT Update 2 October 2015
The consensus is in, and we are relieved to see the Hurricane Joaquin away. Models are effectively unanimous with now very little doubt left among them that the hurricane is not making a US landfall. But in the near term, potentially catastrophic conditions continue over the central Bahamas. Over the weekend, moisture feeds from the hurricane will likely contribute to a major rain event near or over the Carolinas, and perhaps elsewhere. Also, with any more eastward shifts, Bermuda may be at risk later this weekend, or early next week.

Elsewhere, yet more disturbances are coming together out near Hawaii; in the central Atlantic, NHC gives 90L 80% odds of becoming an officiated subtropical or tropical cyclone.
-Ciel

5PM EDT Update 1 October 2015
The model suite has shifted far to the right today after ingesting more concrete information, but this does nothing for the Bahamas, which are experiencing their first October Category 4 hurricane in what may be almost 150 years.

Although the Cone of Uncertainty has thus trended away from the US, it is still much too early to let ones guard down. More model runs will come in, and we will need to see some more run-to-run consistency, and then proof that these latest runs are verifying. Regardless of a direct hit along the east coast or not, potentially catastrophic flooding will be possible over the weekend and/or into early next week from roughly the Carolinas to Northeast.
-Ciel

7AM EDT Update 1 October 2015
Joaquin strengthened a bit more overnight to a 120 mph hurricane. Another Recon plane in on its way this morning to measure the system. It's currently pounding areas of the Central Bahamas, and may do so for another 24 hours. After that the forecast is still uncertain, but there has been a trend east in many of the models overnight.



Those in the cone and mid-Atlantic northward will want to keep watch. A fight between a forming cutoff low over the Southeastern US and systems in the central Atlantic will make the track very prone to changes. Including left or out to sea. Joaquin is not an easy track due to the multiple systems potentially influencing the track, so the good news is it has shifted more east, bringing chances up for a miss out to sea for the US (While the Bahamas get pounded) the bad news, there is still very little confidence in any of those tracks, so there are no all clears for anywhere on the east coast.



The potential for Flooding, regardless of Joaquin, is still very high for the mid-Atlantic.

11:00PM EDT Update 30 September 2015
Hurricane Joaquin has become the second major hurricane of the 2015 Atlantic season. And the official forecast takes it to category 4 while near/over the central Bahamas, and then gradually weakens it as it moves northward toward the mid Atlantic states. Still a great deal of uncertainty as to exact location.

8:45PM EDT Update 30 September 2015
Recon reports from hurricane hunter aircraft suggest that Joaquin has reached category 3 strength, with 115mph winds and 951mb of pressure (and is strengthening). The Automated Tropical Cyclone Forecast System (ATCF) already lists Joaquin as a Category 3 system, soon after the 8PM advisory (which was done when barely any recon data had come in)

An eye is also now visible on IR satellite imagery.



San Salvador island and other nearby islands in the Bahamas may be dealing with extended Major hurricane conditions through Friday.

Beyond Friday, still quite uncertain, but impacts may be felt along the mid Atlantic Coast from the Carolinas to the Delmarva as early as late Saturday or Sunday.

5PM EDT Update 30 September 2015

From the NHC Which now forecasts a landfall near the NC/VA border on Sunday:

1. Preparations to protect life and property within the warning
areas in the Bahamas should be rushed to completion.

2. A significant adjustment to the forecast has been made this
afternoon, and this shows an increased threat to the mid-Atlantic
states and the Carolinas. However, confidence in the details of the
forecast after 72 hours remains low, since we have one normally
excellent model that keeps Joaquin far away from the United States
east coast. The range of possible outcomes is still large, and
includes the possibility of a major hurricane landfall in the
Carolinas.

3. Every effort is being made to provide the forecast models with
as much data as possible. The NOAA G-IV jet has begun a series of
missions in the storm environment, and the National Weather Service
is launching extra balloon soundings.

4. Because landfall, if it occurs, is still more than three days
away, it is too early to talk about specific wind, rain, or surge
impacts from Joaquin in the United States. Even if Joaquin stays
well out to sea, strong onshore winds will create minor to moderate
coastal flooding along the coasts of the mid-Atlantic and
northeastern states through the weekend.

5. A hurricane watch for a portion of the U.S. coast could be
required as early as Thursday evening.

6. Many areas of the eastern U.S. are currently experiencing heavy
rains and gusty winds associated with a frontal system. This
inclement weather is expected to continue over the next few days,
which could complicate preparations for Joaquin should it head
toward the coast, and greatly exacerbate the impacts from the
hurricane. Heavy rains are likely to continue over these areas
even if the center of Joaquin stays out to sea.

11AM EDT Update 30 September 2015

Joaquin has strengthened a bit and moved a bit south of the 5am forecast. The extended range forecast is a down the middle run between the operational run of the ECMWF model and most of the other modes, in short very uncertain.

The 11 AM NHC Discussion has a new change likely brought on by Sandy:

These Key points, especially in a complicated forecast position. I bolded a few interesting points.

1. Confidence in the details of the track forecast late in the
period remains low, since the environmental steering currents are
complex and the model guidance is inconsistent. A wide range of
outcomes is possible, from a direct impact of a major hurricane
along the U.S. east coast to a track of Joaquin out to sea away from
the coast. It is therefore way too soon to talk about specific
wind, rain, or surge impacts from Joaquin in the U.S
.

2. Should the threat to the U.S. increase, any further adjustments
of the forecast to the west would likely be accompanied by an
increase in the forecast forward speed, with impacts along the coast
occurring sooner than currently forecast. A hurricane watch could
be required for portions of the U.S. coast as early as Thursday
evening.


3. Many areas of the eastern U.S. are currently experiencing heavy
rains and gusty winds associated with a frontal system. This
inclement weather is expected to continue over the next few days,
which could complicate preparations for Joaquin should it head
toward the coast.


7:45AM EDT Update 30 September 2015
Based on a recon report of 971 mb, Joaquin has been upgraded to a category 1 hurricane. The forecast track is very uncertain, and relies on how far west and south the system goes. It is forecast to near the central Bahamas then turn late Friday. Beyond that, anyone along the east coast should be paying attention, particularly the Mid Atlantic (NC/VA) northward toward Long Island.



Florida is much less likely due to the high currently moving in (with a low to the north) and the jet core forcing the system more north--use water vapor satellite to show this--, so the Mid Atlantic states and northward seems more likely. however, beach surf conditions could be rough this weekend there. It should allow the cool front to pass down bringing down temperatures in Florida late Friday
However, Joaquin should be watched until the foretasted move northward occurs.

11PM EDT Update 29 September 2015
Hurricane watches are now up for the central Bahamas as the forecast takes Joaquin very near. The forecast is for a category 2 hurricane, but it could be stronger than that as shear relaxes.



Beyond 48-72 hours, the track remains very divergent, and those along the East Coast, particularly the Mid Atlantic to New England should watch Joaquin very closely. (Northeast NC and Southeast Virginia in particular). But any US impacts are still highly uncertain at this time. Mainly because of Joaquin being sandwiched between 4 different areas, thus leaving it in very weak steering currents, with the high south of ex-99L pulling it west currently. It's stuck between various elements that could pull it either way, with how fast determining how close it gets to the east coast or not.

More watches/warnings for the Bahamas are likely tomorrow.


Original Update
In the generally sheared environment of the 2015 Atlantic Hurricane season, we have another entry in the highly sheared and uncertain storms. This time Tropical Storm Joaquin, which again has a highly mixed set of models, in fact beyond 48 hours, the forecast is basically a wild guess at this point. The National Hurricane Center discussion reflects this.



Joaquin is now a 45mph tropical storm drifting westward around 5mph. It's fighting northerly shear and in generally unfavorable conditions, despite that is has a chance to strengthen as the shear is expected to lessen later today and more within the next 2 days. Recon aircraft is measuring the atmosphere around the system, so at this point it's just monitor it along the east coast until a definite trend and motion begins. New England into Canada probably should watch this closely.

Ida's remnants has a chance to reform as well, which is also adding a bit of complexity to the forecast for Joaquin.

{{BahamasMedia}}

{{BermudaNews}}

{{StormLinks|Joaquin|11|11|2015|11|Joaquin}}

{{StormLinks|90|90|13|2015|90|Invest 90L}}

{{NortheastGulfRadar}}

{{MidAtlanticRadar}}

{{NERadar}}

{{NCCoastMedia}}





cieldumort
(Moderator)
Tue Sep 29 2015 12:47 PM
Re: Tropical Storm Joaquin

The area of disturbed weather where Ida was is now a mish-mash of the Ida remnants and a portion of a frontal trof. As such, Ida's remnants have been re-tagged 90L.

MikeCAdministrator
(Admin)
Tue Sep 29 2015 02:30 PM
Re: Tropical Storm Joaquin

From Recon:

No vortex yet, but 55 knot SMFR winds (~65MPH) and 990mb pressure. If this holds up, Joaquin may be rapidly strengthening right now.



MikeCAdministrator
(Admin)
Tue Sep 29 2015 02:49 PM
Re: Tropical Storm Joaquin

Convection is moving more over the center, which would allow for another run of strengthening. The NHC's 11AM intensity forecast was way underestimated it appears.

MikeCAdministrator
(Admin)
Tue Sep 29 2015 03:04 PM
Re: Tropical Storm Joaquin

Vortex message 990mb, and an eyewall is forming along the eastern side of the center. Joaquin is going for hurricane.

"50 PERCENT BAND AROUND EAST HALF OF CENTER
850 MB CENTER LOCATED NEAR RADAR BAND"


This being the case, it's ahead (time wise) of most of the intensity models that were forecasting a hurricane.


MikeCAdministrator
(Admin)
Tue Sep 29 2015 03:18 PM
Re: Tropical Storm Joaquin

Another SMFR, ~70mph winds, Joaquin may hit hurricane tonight.



Hawkeyewx
(Weather Analyst)
Tue Sep 29 2015 03:51 PM
Re: Tropical Storm Joaquin

I love watching systems like this that are moving into better conditions(the opposite of every other system this year). Once the shear relaxes just enough for convection to hold over the center, boom, off it goes. The water vapor loop shows excellent outflow to the south with the cirrus exhaust slowly trying to inch its reach to the west and north.

MikeCAdministrator
(Admin)
Tue Sep 29 2015 04:40 PM
Re: Tropical Storm Joaquin

Based on recon reports, center is roughly where the arrow points in the image below. A bit south (35 miles) of the 11AM position.



MikeCAdministrator
(Admin)
Wed Sep 30 2015 01:00 AM
Re: Tropical Storm Joaquin

Looks like an eye may be forming, Joaquin is going through a fair bit of strengthening right now.

Doombot!
(Weather Guru)
Wed Sep 30 2015 01:28 AM
Re: Tropical Storm Joaquin

What's odd is that on half of the satellite views and eye seems to be forming, but on the other half it simply looks like weakening in the entire western half. It will be very interesting to see what happens in the next few frames...

Either way, it looks like we probably have an October surprise on our hands.

D!


LoisCane
(Veteran Storm Chaser)
Wed Sep 30 2015 02:12 AM
Re: Tropical Storm Joaquin

Close in ... home grown sort of October Surprise.

LoisCane
(Veteran Storm Chaser)
Wed Sep 30 2015 02:14 AM
Re: Tropical Storm Joaquin

Seems the way to get a storm to develop this year was not to start with a Cape Verde Wave... after all those waves, this one pops up close in. Developing tonight, compelling loops and models. Don't think the front is all that impressive currently though much can change

craigm
(Storm Tracker)
Wed Sep 30 2015 05:41 AM
Re: Tropical Storm Joaquin

Persistence is an interesting word. If Joaquin makes a slower turn than what the models are showing, although they have performed flawlessly this year?, that doesn't leave a lot of wiggle room in Fl.

Random Chaos
(Weather Analyst)
Wed Sep 30 2015 06:47 AM
Re: Tropical Storm Joaquin

Internal structure has made remarkable improvement overnight from a comma head when I went to sleep to a well formed (albeit broken) spiral.

85GHz pass, source NRL:



MikeCAdministrator
(Admin)
Wed Sep 30 2015 07:40 AM
Re: Tropical Storm Joaquin

The latest recon vortex message is down to 972 mb, although the winds haven't really caught up to that yet. Recon also reporting the central dense overcast is on tap, so looks like it may intensify this morning. Recon's center fix is also 40 miles sse of the 5am position.

MikeCAdministrator
(Admin)
Wed Sep 30 2015 11:12 AM
Re: Tropical Storm Joaquin

The 11 AM Discussion has a new change likely brought on by Sandy:

These Key points, especially in a complicated forecast position. I bolded a few interesting points.

1. Confidence in the details of the track forecast late in the
period remains low, since the environmental steering currents are
complex and the model guidance is inconsistent. A wide range of
outcomes is possible, from a direct impact of a major hurricane
along the U.S. east coast to a track of Joaquin out to sea away from
the coast. It is therefore way too soon to talk about specific
wind, rain, or surge impacts from Joaquin in the U.S
.

2. Should the threat to the U.S. increase, any further adjustments
of the forecast to the west would likely be accompanied by an
increase in the forecast forward speed, with impacts along the coast
occurring sooner than currently forecast. A hurricane watch could
be required for portions of the U.S. coast as early as Thursday
evening.


3. Many areas of the eastern U.S. are currently experiencing heavy
rains and gusty winds associated with a frontal system. This
inclement weather is expected to continue over the next few days,
which could complicate preparations for Joaquin should it head
toward the coast.


Doombot!
(Weather Guru)
Wed Sep 30 2015 11:19 AM
Re: Tropical Storm Joaquin

It's good that the NHC is providing an "executive summary", but they should move it to the header rather than the footer.

If you're not hurricane geeks like us, I suspect a lot of people simply see the discussions as nonsense.


MikeCAdministrator
(Admin)
Wed Sep 30 2015 07:54 PM
Re: Tropical Storm Joaquin

Recon is out in the storm again right now, recently found a 95 knot flight level wind, no vortex yet (just got there)

MikeCAdministrator
(Admin)
Wed Sep 30 2015 07:56 PM
Re: Tropical Storm Joaquin

949mb extra, smfr wind of 102knots. Waiting for a bit more to verify, but it should be bumped up a little.

MikeCAdministrator
(Admin)
Wed Sep 30 2015 08:01 PM
Re: Tropical Storm Joaquin

Yep 8PM, 954mb and 105mph winds, a Category two. A bit quicker than forecast, has a shot for major tomorrow.

MikeCAdministrator
(Admin)
Wed Sep 30 2015 08:10 PM
Re: Tropical Storm Joaquin

Ok after the 8pm update, recon seems to be settling around 113 knots at flight level and and surface 100 knot winds via SFMR. I.e. it may be a major hurricane now, and officially at 11PM.



.


MikeCAdministrator
(Admin)
Wed Sep 30 2015 08:35 PM
Re: Tropical Storm Joaquin

ATCF Best Track system now showing a Cat 3 hurricane 115mph winds, 951mb.

AL, 11, 2015100100, , BEST, 0, 239N, 730W, 100, 951, HU


danielwAdministrator
(Moderator)
Wed Sep 30 2015 08:46 PM
Cat 2 Hurricane Joaquin

They may do a Special Update when they make the pass through the NE Quad. Should be in the next hour.

The 109 knots reading was in the NW Quad and I'm not sure if that Quad qualifies as Front Right Quadrant right now.

Joaquin is moving just South of due West and that would put the NW Quadrant and the Right Front Quadrant.

Waiting on the NE Quadrant segment to see what they find.

Definitely straddling the fence on Cat 2/ Cat 3 Hurricane.

(edited 109 mph to 109 knots-danielw)


MikeCAdministrator
(Admin)
Wed Sep 30 2015 09:20 PM
Re: Cat 2 Hurricane Joaquin

Recon data was skipping a few points and now stopped, so the data transmission system may be down.

danielwAdministrator
(Moderator)
Wed Sep 30 2015 09:58 PM
Re: Cat 2 Hurricane Joaquin

I was searching and not finding a data feed anywhere. So I guess we are in limbo.
Very unusual to lose all data links. Haven't seen that in a while.


Random Chaos
(Weather Analyst)
Wed Sep 30 2015 11:56 PM
Re: Cat 2 Hurricane Joaquin

Came across this animation that shows Sept 22nd to present the formation of Hurricane Joaquin - very non-standard formation, and tons of environmental conditions that we normally don't see around hurricanes:

http://api.viglink.com/api/click?format=...ntral%20%2F200h


MikeCAdministrator
(Admin)
Thu Oct 01 2015 08:09 AM
Re: Cat 2 Hurricane Joaquin

Latest recon suggesting Joaquin's making a run for a Cat 4 hurricane. Pressure dropping quite a bit and 130kt SMFR winds. Southward motion still continuing as of now, a bit east and south of the 5AM NHC position.



MikeCAdministrator
(Admin)
Thu Oct 01 2015 11:31 AM
Re: Cat 2 Hurricane Joaquin

935.1 mb pressure from recon, still getting stronger.

craigm
(Storm Tracker)
Thu Oct 01 2015 12:15 PM
Re: Cat 2 Hurricane Joaquin

Last few loops, pick any one, look like the turn has started.
Possibly an eye wobble, typical with stronger storms, will have to see.


doug
(Weather Analyst)
Thu Oct 01 2015 12:50 PM
Re: Cat 2 Hurricane Joaquin

looks mostly westward to me, which is a sign of a more northward track.

MikeCAdministrator
(Admin)
Thu Oct 01 2015 01:03 PM
Re: Cat 2 Hurricane Joaquin

Yes, recon fixes are showing wsw motion now.

MikeCAdministrator
(Admin)
Thu Oct 01 2015 01:27 PM
Re: Cat 2 Hurricane Joaquin

Latest vortex fix has it at 937, and just north of Crooked island in the Bahamas. (The weather stations there stopped reporting over an hour ago). Based on the recon fixes, It's moving mostly west, with just a hair bit of southerly motion now.

doug
(Weather Analyst)
Thu Oct 01 2015 01:33 PM
Re: Cat 2 Hurricane Joaquin

The progress of the trough in the GOM has not been slowed a bit by the storm. The latest GFS is more consistent with the Euro. It looks like the cutoff low, if it does form, is in western KY which should not draw the storm back to the west. I feel safer driving to NC this weekend now.

cieldumort
(Moderator)
Thu Oct 01 2015 02:21 PM
Re: Hurricane Joaquin Battering the Central Bahamas




MikeCAdministrator
(Admin)
Thu Oct 01 2015 02:38 PM
Re: Hurricane Joaquin Battering the Central Bahamas

Joaquin will spend nearly 12-16 hours over the Central Bahamas (particularly Long Island, Crooked Island, San Salvador, and Rum Cay) with category 4 conditions. The Bahamas have had majors before, but I don't remember any hanging over them this long.

Some videos from earlier this morning over at Crooked Island (Center of Joaquin is just north of here now).

{{YouTube|R03uScBCwgA}}

more recently:

{{YouTube|Cak3aSSLY4w}}


MikeCAdministrator
(Admin)
Thu Oct 01 2015 03:46 PM
Re: Cat 2 Hurricane Joaquin

The southwesterly motion has resumed, or at least wobbling more southwest. It appears it going to be a bit further west/south than forecast in the near term. (both official and models)


StormHound
(Weather Guru)
Thu Oct 01 2015 04:16 PM
Re: Cat 2 Hurricane Joaquin

Quote:

The southwesterly motion has resumed, or at least wobbling more southwest. It appears it going to be a bit further west/south than forecast in the near term. (both official and models)





Seems the turn to the north should have already started according to models, but I don't see it yet.


Tazmanian93
(Weather Master)
Thu Oct 01 2015 04:18 PM
Re: Cat 2 Hurricane Joaquin

At 200 PM EDT (1800 UTC), the center of Hurricane Joaquin was
located near latitude 23.0 North, longitude 74.2 West. Joaquin is
moving generally southwestward at about 6 mph (9 km/hr), and a
southwestward or westward motion is expected to continue through
tonight. A turn toward the northwest and north is expected on
Friday, and a faster motion toward the north is expected Friday
night and Saturday
Quote:

Quote:

The southwesterly motion has resumed, or at least wobbling more southwest. It appears it going to be a bit further west/south than forecast in the near term. (both official and models)





Seems the turn to the north should have already started according to models, but I don't see it yet.




StormHound
(Weather Guru)
Thu Oct 01 2015 04:37 PM
Re: Cat 2 Hurricane Joaquin

Quote:

..A turn toward the northwest and north is expected on
Friday, and a faster motion toward the north is expected Friday
night and Saturday
Quote:



Still looks due West by my reckoning. There was a wobble to the NW, but it seems just a wobble as it came back down south. Have to see what the next several hours bring, but it looks west of forecast track.

cieldumort
(Moderator)
Thu Oct 01 2015 04:49 PM
Re: Hurricane Joaquin Battering the Central Bahamas



Tazmanian93
(Weather Master)
Thu Oct 01 2015 04:54 PM
Re: Hurricane Joaquin Battering the Central Bahamas

I just saw that and was looking it up to verify

DaViking
(Verified CFHC User)
Fri Oct 02 2015 01:33 AM
Re: Hurricane Joaquin Battering the Central Bahamas

Can't really remember a time where a "major hurricane", never really managed to develop that "signature" defined eye on imagery, unless the eye is really small.

But even Hurricane Wilma in 05 had a distinct eye when it peaked.

I'm just making an observation. EL NINO RIGHT?!?


cieldumort
(Moderator)
Fri Oct 02 2015 01:41 PM
Re: Joaquin in the Central Bahamas Starting to Eject N-NNE



cieldumort
(Moderator)
Fri Oct 02 2015 09:56 PM
Re: Joaquin in the Central Bahamas Starting to Eject N-NNE

Virginia Beach [i](Image was deleted because of image display problems.)[/i]

Random Chaos
(Weather Analyst)
Sat Oct 03 2015 12:54 AM
Re: Joaquin in the Central Bahamas Starting to Eject N-NNE

Quote:

Virginia Beach




That would be from the nor'easter we're getting in the mid-atlantic, not the hurricane. I find it interesting on the IR loop that it looks like the nor'easter is being fed from the hurricane, almost as if the nor'easter is cannibalizing the hurricane. Meanwhile the hurricane appears to be weakening while the nor'easter is getting stronger. Very odd:

http://www.ssd.noaa.gov/goes/east/nwatl/h5-loop-avn.html

http://www.ssd.noaa.gov/goes/east/nwatl/h5-loop-wv.html


JoshuaK
(Weather Guru)
Sat Oct 03 2015 08:47 AM
Re: Joaquin in the Central Bahamas Starting to Eject N-NNE

Joaquin looks to be much stronger this morning with a much more defined appearance on satellite. Recce found flight level winds of 129 knots as well, whether this is from the completion of a ERC or moving away from upwelled waters, Joaquin doesn't appear to be suffering much from the increasing wind shear.

Hawkeyewx
(Weather Analyst)
Sat Oct 03 2015 11:04 AM
Re: Joaquin in the Central Bahamas Starting to Eject N-NNE

Latest recon pass measured 144 kts at flight level and 138 kts SFMR.

cieldumort
(Moderator)
Sat Oct 03 2015 11:48 AM
Re: Joaquin in the Central Bahamas Starting to Eject N-NNE

The last passes through is suggestive a possible upgrade to Cat 5. Min pressure could also be lower than listed here -

A. Time of Center Fix: 3rd day of the month at 14:51:00Z
B. Center Fix Coordinates: 25°51'N 71°48'W (25.85N 71.8W)

D. Estimated (by SFMR or visually) Maximum Surface Wind: 138kts (~ 158.8mph)

F. Maximum Flight Level Wind Inbound: From 233° at 144kts (From the SW at ~ 165.7mph)

H. Minimum Sea Level Pressure: 934mb (27.58 inHg) - Extrapolated
L. Eye Character: Closed
M. Eye Shape & Diameter: Circular with a diameter of 20 nautical miles (23 statute miles)


Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 144kts (~ 165.7mph) which was observed 14 nautical miles (16 statute miles) to the SSE (148°) from the flight level center at 14:46:30Z
Sea Level Pressure Extrapolation From: 700mb

Eye sonde failed. Moderate turbulence inbound. Clear above in Cente


cieldumort
(Moderator)
Sat Oct 03 2015 02:52 PM
Re: Joaquin Heading Northeast, Back to Cat 4

The widespread coastal gale and flood threat continues, and will likely do so through the weekend, and even into Monday, only shifting in locations as Joaquin tracks further northeast.

This setup is somewhat similar to a nor'easter, in that there is strong High over Low pressure, but it is not one. In this situation there is very high pressure centered over northeastern Canda, with extremely low pressure centered way down south - just north of the Bahamas - and it is a hurricane, rather than an extra-tropical cyclone (Hurricane Joaquin).

As can be seen in the image below, as lines of equal pressure (isobars) get packed tighter and tighter, the greater the wind speed becomes. In the case of Joaquin to the south and the large and powerful High to his north-northwest, as well as another anticyclone to his northeast and a weaker low to his northwest, these winds cover thousands of miles, and the subsequent fetch of water being pushed into the eastern seaboard from the Atlantic goes on and on, coming all the way in from even the central Atlantic.


Image credit: TropicalTidbits.com



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