MikeC
|
| (Admin) |
| Wed Jul 27 2011 08:53 PM |
Tropical Storm Don Heading Toward Texas
|
10:45 PM EDT (9:45 PM CDT) 28 July 2011 Update
With the 11PM (10PM CDT) Hurricane Center Advisory, Tropical Storm Warnings were applied further southward to the Texas/Mexico border. And because of a jog to the west the official track takes it into Kenedy county Texas (pop 416), just north of Brownsville. This same mostly unpopulated coastal county was where Bret in 1999 made landfall.
Any further southward jog would take it toward South Padre Island or Brownsville.
Don had a burst of convection earlier and strengthened slightly, but it still remains under some shear and still remains tilted. It's wind speed has increased to 50MPH. IT has a small window of opportunity to increase but the Official forecast keeps it below hurricane strength, and there is still no good reason to doubt that.
Don is currently weakening slightly again, and probably will hover around where it is at. Based on charts, it may weaken further as it approaches the coastline.
The benefit of the earlier burst of convection is that served to make the area covered by Don a bit larger, so more areas would get rainfall, but the heaviest is mostly on the south side of the system where the convection is being blown off.
7:45 PM EDT (6:45 PM CDT) 28 July 2011 Update
The official 8PM position is 24.7N 91.8W, the NHC in the advisory considered it a westward jog. More data from the planes coming later should be interesting.
Also the Central Atlantic wave (no invest yet) has a 20% chance for development over the next 48 hours, so we may go from Don right into tracking another system.
6:15 PM EDT (5:15 PM CDT) 28 July 2011 Update
One of the more interesting aspects of tropical meteorology involves how quickly things sometimes can change in the tropics, especially with a system like Don.
The image above shows a "hot tower" or an area of the storm that shoots up in the atmosphere quickly, usually indicating strengthening, in this case it may mean that Don may be relocating a bit south of the 5PM Advisory position, which would shift the track to the left. This is also an indicator it may be deflecting some of the northerly shear and starting to look more like a classic Tropical Storm on satellite imagery.
The recon reports above also indicate that the center may be reforming further southward.
Nothing too alarming as of yet, but it is an indication that Don should not be ignored. The "all clear" is not out on the system yet, in fact moving to the south gives it a better opportunity to strengthen before landfall.
As recon reports come in, we'll update the site.
IMeteorologist Ed Dunham on Don available here.
The wave in the Central Atlantic (no invest yet) will likely be worth watching into next week, so not much break after Don.
5 PM EDT (4 PM CDT) 28 July 2011 Update
The 5PM update offers no real change, other than shifting the track slightly southward, it appears the vertical/easterly shear that is affecting Don now will last through landfall, keeping Don a rainmaker as a tropical storm on landfall. If this shear remains through landfall, as in the forecast, most of the rain will be around the center and just to the south of landfall (vs a 'healthy' system that would tend to prefer northern rainfall), unfortunately for most of Texas. Some parts will still get rain on the northern side, but not as much as you may expect from a tropical system. Still it will help the drought stricken areas.
It still has a full day to change, and get a little stronger, so it's not over yet, as a small system it can change up or down very rapidly.
Those in the Tropical Storm Warning area should pay attention to local statements and media regarding your situation.
11 AM EDT (10 AM CDT) 28 July 2011 Update
Tropical Storm Warnings are now up in southeast Texas from Port Mansfield (north of South Padre Island) northward to San Luis Pass (Just southwest of Galveston). This means that the hurricane center is expecting tropical storm conditions within 36 hours. Landfall is still expected in the overnight hours Friday evening into Saturday.
The good news it appears any chance of it becoming a hurricane are waning by the hour, which means it's a good shot as a rainmaker for parts at and north of the landfall point, if the shearing continues like it has though, most of the rain may actually be toward the southern side. It is forecast that vertical wind shear and dry air will keep the system below hurricane strength, and I see no reason to doubt that.
5 AM EDT (4 AM CDT) 28 July 2011 Update
Tropical Storm watches are now up for Texas from the Mexico Border/Rio Grande northward to San Luis Pass, this means that tropical storm force conditions are expected for the area within 48 hours.
The good news this morning is that Don is struggling battling the ridge and dry air, and has remained weak, as a borderline Tropical Storm overnight. Particularly weak on the in-feed on the western side of the storm. It's a small storm, with tropical storm force winds extending outward just 45 miles from the center.
This has shifted the official forecast track a bit further south toward Corpus Christi, and it may be adjusted slightly further south from there. The middle Texas coast has the highest chance for landfall.
Don is expected to increase in forward speed later today, and the current forecast sets the landfall time overnight Friday into Saturday. Don, however, remains a fairly well organized system at its core, and remains intact with convection continuing to fire over the low level circulation center. Which means it is not weakening (But not strengthening currently either), and should be watched closely during the day for changes. It's a small storm, with tropical storm force winds extending outward just 45 miles from the center. The first chance for it to organize more comes this afternoon as it moves away from the Yucatan.
This means that Don is most likely going to be a rainmaker for Texas, probably not as much area of Texas as one would hope for most of Texas, but a rainmaker none the less. The areas that do get rainfall will likely experience heavy
amounts. Also with tropical storms, especially as they near hurricane force, you can see short lived/weak tornadoes on either side of the landfall, some surge both mostly north of the landfall.
Currently since Don remains a small storm, it is very easily affected by conditions around it. This may be a good thing now in the near term, as it is likely to keep the system generally weaker, but potentially more dangerous in the long term since it could change relatively quickly if conditions in the Gulf improve.
With the tropical storm watches the expectations are that it will not reach hurricane force. Those in Texas should continue to monitor it very closely to see what the trends are over today. One of the first chances that the system will have to get more organized comes mid to late today.
Those in the watch area, please monitor local media/officials for more information if things change. There sill exists, with the small system, that it could organize rather quickly once it moves into the western Gulf, and could still be a hurricane at that time, but the current thought from the National Hurricane Center is that it will not.
Those in the watch area should know that the hurricane center fully updates Every 6 hours, which includes (Times CST) 5AM, 10AM, 5PM, 10PM, and also issues intermediate advisories when there are watches/warnings up at 7AM, 1PM, 7PM, and 1AM. If a very rapid change were to occur they will issue a special statement (Usually after recon findings), these are rare, but could happen anytime. So you can schedule checks around those times.
Track Mark Sudduth from HurricaneTrack.com on a map as he heads toward Texas for Don.
Original Update
Based on Recon Data, Tropical Storm Don has formed from the wave now entering the Southern Gulf of Mexico (90L), just north of the Yucatan Peninsula.
Those in Texas will want to watch this closely. Currently there are no watches and warnings in effect, but interest in the norwestern Gulf of Mexico should monitor the progress of Don. Watches/Warnings may go up later tonight for portions of Texas.
Those along the Texas coastline in the Official Forecast Cone (particularly Texas from Galveston southward into Brownsville) will need to listen closely to local media and officials if and when watches/warnings are issued. Currently the forecast keeps it a Tropical Storm, but there is a window where it could become a hurricane after 48 hours (Right before landfall).
The track is forecasted to be generally west northwest to northwest and expected to bend more westward around midday Friday, approaching Central Texas coast overnight Friday evening.
As a rainmaker, Don probably won't do too much, unfortunately, as it covers a small area. The area that does get the rain, I'm sure will take it though. The best case is that Don stays weaker and gives at least some rain to areas in Texas that need it very badly. Those at and just north of landfall point will receive the most rain, and in some areas it could be as much as 3-6".
Outside of Don, there is an area in the eastern Caribbean that may be worth watching next week.
Cancun radar recording of 90L approach
Webcam Recording: Cancun Beach Palace roof looking north northeast along the beach.
{{TexasGulfRadar}}
{{StormLinks|Don|04|4|2011|1|Don}}
{{StormLinks|91L|91|5|2011|2|91L}}
Long Term Floater Recordings of Don:
Visible Floater Recording of Don
Water Vapor Floater Recording of Don
Rainbow IR Floater Recording of Don
Don Approach Related Links:
Color Sat of Gulf
Emergency Management:
Texas Division of Emergency Management
Texas Emergency Management Reports
AEP Texas Power Outage Map
Local Media/Television
Corpus Christi:
KRIS TV 6 (NBC Corpus Christi)
KZTV 10 (CBS Corpus Christi)
KIII TV 3 (ABC Corpus Christi)
Brownsville:
KGBT 4 News Brownsville
KRGV Newschannel 5 Brownsville
KURV 710 News/Talk Brownsville
Houston:
KHOU the CBS affiliate in houston, is former Hurricane Center director Neil Frank's station, and likely will begin streaming once warnings are up in the area
Channel 2 NBC affiliate in Houston
ABC 13 in Houston
Houson Fox 26
Radio
KTRH Rado News/Talk station in Houston with streaming
Other Houston area radio
Newspapers
Corpus Christi Caller-Times
Houston Chronicle
Brownsville Herald
The Monitor
Valley Morning Star
|
danielw
|
| (Moderator) |
| Wed Jul 27 2011 08:55 PM |
|
|
Re: Tropical Storm Don forms in Southern Gulf of Mexico
|
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 27th day of the month at 20:32Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 300)
Mission Purpose: Investigate third suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 09
A. Time of Center Fix: 27th day of the month at 20:01:40Z
B. Center Fix Coordinates: 22°08'N 86°49'W (22.1333N 86.8167W)
B. Center Fix Location: 68 miles (110 km) to the N (1°) from Cancún, Quintana Roo, México.
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 29kts (~ 33.4mph)
E. Location of the Estimated Maximum Surface Wind: 26 nautical miles (30 statute miles) to the NNW (336°) of center fix
F. Maximum Flight Level Wind Inbound: From 101° at 34kts (From between the E and ESE at ~ 39.1mph)
G. Location of Maximum Flight Level Wind Inbound: 25 nautical miles (29 statute miles) to the NNW (329°) of center fix
H. Minimum Sea Level Pressure: 1001mb (29.56 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 22°C (72°F) at a pressure alt. of 313m (1,027ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 26°C (79°F) at a pressure alt. of 348m (1,142ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 16°C (61°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Levels (sfc and flt lvl centers are within 5nm of each other): Surface and 1,500 feet
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 3 nautical miles
Remarks Section:
Maximum Flight Level Wind: 34kts (~ 39.1mph) in the northwest quadrant at 19:49:40Z
Sea Level Pressure Extrapolation From: Below 1,500 feet
|
MikeC
|
| (Admin) |
| Wed Jul 27 2011 10:19 PM |
|
Re: Tropical Storm Don forms in Southern Gulf of Mexico
|
I added a lot of local links for Don cone areas from Brownsville to Galveston on the front page.
The next recon flight is scheduled for 8AM EDT tomorrow.
| WeatherNut |
| (Weather Master) |
| Wed Jul 27 2011 11:09 PM |
|
Re: Tropical Storm Don forms in Southern Gulf of Mexico
|
Transmitted: 27th day of the month at 21:36Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 300)
Mission Purpose: Investigate third suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 12
A. Time of Center Fix: 27th day of the month at 21:10:50Z
B. Center Fix Coordinates: 22°14'N 86°56'W (22.2333N 86.9333W)
B. Center Fix Location: 75 miles (121 km) to the N (355°) from Cancún, Quintana Roo, México.
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 36kts (~ 41.4mph)
E. Location of the Estimated Maximum Surface Wind: 22 nautical miles (25 statute miles) to the SSE (148°) of center fix
F. Maximum Flight Level Wind Inbound: From 187° at 43kts (From the S at ~ 49.5mph)
G. Location of Maximum Flight Level Wind Inbound: 20 nautical miles (23 statute miles) to the SSE (150°) of center fix
H. Minimum Sea Level Pressure: 1000mb (29.53 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 19°C (66°F) at a pressure alt. of 303m (994ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 25°C (77°F) at a pressure alt. of 304m (997ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 18°C (64°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Levels (sfc and flt lvl centers are within 5nm of each other): Surface and 1,500 feet
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 3 nautical miles
Remarks Section:
Maximum Wind Outbound: 46kts (~ 52.9mph) in the northwest quadrant at 21:12:00Z
Maximum Flight Level Wind: 46kts (~ 52.9mph) in the northwest quadrant at 21:12:00Z
Sea Level Pressure Extrapolation From: Below 1,500 feet
| WesnWylie |
| (Weather Guru) |
| Wed Jul 27 2011 11:55 PM |
|
Re: Tropical Storm Don forms in Southern Gulf of Mexico
|
TS Don is taking on the typical Tropical Storm signature. There is some really nice banding on the latest visible satellite image. Convection has died down near the center of circulation, but at the same time, a more intense band is beginning to develop across the southeastern portion of the cyclone.
http://www.ssd.noaa.gov/goes/east/gmex/vis.jpg
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 12:24 AM |
|
Re: Tropical Storm Don forms in Southern Gulf of Mexico
|
Added satellite floater recordings of Don that will run until the last advisory.
Floater Recordings of Don:
Visible Floater Recording of Don
Water Vapor Floater Recording of Don
Rainbow IR Floater Recording of Don
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 09:42 AM |
|
Re: Tropical Storm Don forms in Southern Gulf of Mexico
|
Don's dealing with the dry air still at this hour, later today probably will either be a good shot for more development, or Don will likely stay weak the entire run, which is preferred. It would give portions of Texas some much needed rain, but the small size will limit it to only a portion of Texas, while teasing others with the promise. But I'm sure you all there will take what you can get.
So as it stands now, it looks like Don will likely just be a rain maker, with the wise warning to still keep an eye on this one closely as the small size means if it were to hit an area of very favorable conditions, it could blow up quickly. So make sure to have plans in case hurricane watches/warnings are made later. Read the Hurricane Center's discussion for more detail on that.
Those in the watch area should know that the hurricane center fully updates Every 6 hours, which includes (Times CST) 5AM, 10AM, 5PM, 10PM, and also issues intermediate advisories when there are watches/warnings up at 7AM, 1PM, 7PM, and 1AM. If a very rapid change were to occur they will issue a special statement (Usually after recon findings), these are rare, but could happen anytime. So it is very highly recommended you check the official updates during the day and evening , and you can schedule checks around those times.
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 10:46 AM |
|
Re: Tropical Storm Don forms in Southern Gulf of Mexico
|
Since mark from hurricanetrack is heading to Texas, I went ahead and put up the map we used in Earl last year that tracks his position realtime. Track Mark Sudduth from HurricaneTrack.com on a map as he heads toward Texas for Don.
In the meantime, recon is on it's way back now.
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 11:54 AM |
|
|
|
Re: Tropical Storm Don forms in Southern Gulf of Mexico
|
20 minutes ago. Centered on 23.3N, 89.15W. Center appears to be consolidating now that most of the convection is over water.
Recon should be near the Center in the 25 minutes, or less.
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 12:26 PM |
|
|
|
Don Vortex 1
|
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 28th day of the month at 12:20Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 303)
Storm Number & Year: 04L in 2011
Storm Name: Don (flight in the North Atlantic basin)
Mission Number: 2
Observation Number: 03
A. Time of Center Fix: 28th day of the month at 11:55:40Z
B. Center Fix Coordinates: 23°40'N 89°29'W (23.6667N 89.4833W) (View map)
B. Center Fix Location: 438 miles (704 km) to the S (175°) of New Orleans, LA, USA.
C. Minimum Height at Standard Level: 1,437m (4,715ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 30kts (~ 34.5mph)
E. Location of the Estimated Maximum Surface Wind: 34 nautical miles (39 statute miles) to the WNW (297°) of center fix
F. Maximum Flight Level Wind Inbound: From 358° at 19kts (From the N at ~ 21.9mph)
G. Location of Maximum Flight Level Wind Inbound: 3 nautical miles (3 statute miles) to the W (266°) of center fix
H. Minimum Sea Level Pressure: 1002mb (29.59 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 18°C (64°F) at a pressure alt. of 1,522m (4,993ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 21°C (70°F) at a pressure alt. of 1,534m (5,033ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 8°C (46°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 3 nautical miles
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 19kts (~ 21.9mph) in the west quadrant at 11:54:40Z
Maximum Flight Level Wind Outbound: 52kts (~ 59.8mph) in the east quadrant at 11:57:10Z
Sea Level Pressure Extrapolation From: 850mb
Maximum Flight Level Temp: 21°C (70°F) which was observed 20 nautical miles (23 statute miles) to the SW (234°) from the flight level center
Remarks Section - Additional Remarks...
MAX OUTBOUND SFC WINDS VISUALLY 45 KTS SOME RAIN CONTAMINATION ON SFMR
FIX MADE INSIDE CONVECTIVE BAND SLIGHTLY NORTH OF ACTUAL CTR
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 12:44 PM |
|
Re: Don Vortex 1
|
Recon found slightly stronger winds, but the system seems to be tilted. Next advisory probably will have 45MPH winds. The satellite images still have a fairly sheared presentation. But as this gets away from the Yucatan it'll probably improve later today. Vertical instability in the gulf is actually unusually low, so this is an interesting negative factor for development (at least against rapid intensification) that may keep it from really organizing.
| WesnWylie |
| (Weather Guru) |
| Thu Jul 28 2011 12:50 PM |
|
Re: Don Vortex 1
|
TS Don has shifted north of the 4:00 AM CDT track. I am not sure if it is the typical "wobble" that tropical systems do when undergoing strengthening, or if it is an actual trend. If it continues to move more toward the northwest, rather than west-northwest, I wonder how that will affect the track? It seems like it would increase confidence in a landfall near Corpus Christi, rather than farther to the south near Brownsville.
I guess we'll have to see what the 12z models have in store.
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 01:03 PM |
|
|
|
Don Track
|
I quickly plotted out a 308 degree heading. Extrapolated to the Texas Coast brought Don ashore just south of Palacios,TX.
That's the extrapolated method using the 2 AM fix and the latest center fix by Recon. Not scientific at all. Quick guess method. Just watch the extrap on the Main page under the SFWMD model link.
Latest, that I can pull,satellite shot. Still centered on 23.3N/ 89.15W for tracking purposes. Decent growth/ expansion over 30 minutes. When compared to the earlier image above.
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 01:12 PM |
|
|
|
Recon
|
The data from Recon is some of the oddest data I've seen from a tropical storm. Flight level winds are not what you would normally see flying the standard "X" pattern.
We may see a Center jump due to this. The Center appears to be elongated on a NW to SE line. Oblong, if you will.
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 01:25 PM |
|
Re: Recon
|
Quote:
The data from Recon is some of the oddest data I've seen from a tropical storm. Flight level winds are not what you would normally see flying the standard "X" pattern.
We may see a Center jump due to this. The Center appears to be elongated on a NW to SE line. Oblong, if you will.
The temperature difference from the surface to higher levels in the atmosphere is actually pretty abnormally low, it's really an unusual situation in the Gulf right now. The system looks tilted, like it could reform center wise, but the lack of the vertical gradient looks like it's going to keep rapid intensification off the table, at least today. Still it could see slow strengthening today unless the dry air takes its toll.
| MichaelA |
| (Weather Analyst) |
| Thu Jul 28 2011 01:25 PM |
|
|
Re: Recon
|
Convection seems to be improving and increasing near the center as this morning progresses. With light shear and high SSTs, some intensification is probable. The only limiting factor I see is the dry air directly in Don's path.
| hogrunr |
| (Weather Guru) |
| Thu Jul 28 2011 02:30 PM |
|
|
Re: Recon
|
What was the official center fix for this last recon flight? I'm having trouble seeing where they determined it was.
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 02:34 PM |
|
|
|
Re: Recon
|
Latest water vapor imagery indicates Don has lost the tail of convection that was over the Yucatan Channel earlier. This is probably due to the Northerly winds just to the east of Don.
Don is in a pinch area between a ULL to the west. and east with a ridge descending and squeezing the eastern ULL.
Kind of like a doughnut in your hands being pressed from both sides. Oblong for now.
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 28th day of the month at 14:22Z
Corrected: This observation corrected a previous observation.
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 303)
Storm Number & Year: 04L in 2011
Storm Name: Don (flight in the North Atlantic basin)
Mission Number: 2
Observation Number: 07
A. Time of Center Fix: 28th day of the month at 13:50:10Z
B. Center Fix Coordinates: 23°59'N 89°55'W (23.9833N 89.9167W)
B. Center Fix Location: 414 miles (667 km) to the S (179°) of New Orleans, LA, USA.
C. Minimum Height at Standard Level: 1,442m (4,731ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 29kts (~ 33.4mph)
E. Location of the Estimated Maximum Surface Wind: 2 nautical miles (2 statute miles) to the SSW (201°) of center fix
F. Maximum Flight Level Wind Inbound: From 81° at 32kts (From the E at ~ 36.8mph)
G. Location of Maximum Flight Level Wind Inbound: 2 nautical miles (2 statute miles) to the NNW (346°) of center fix
H. Minimum Sea Level Pressure: 1001mb (29.56 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 18°C (64°F) at a pressure alt. of 1,523m (4,997ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 26°C (79°F) at a pressure alt. of 1,515m (4,970ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 8°C (46°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Levels (sfc and flt lvl centers are within 5nm of each other): Surface and 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1.5 nautical miles
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 52kts (~ 59.8mph) in the east quadrant at 11:57:10Z
Maximum Flight Level Wind Outbound: 38kts (~ 43.7mph) in the southeast quadrant at 14:15:50Z
Sea Level Pressure Extrapolation From: 850mb
Remarks Section - Additional Remarks...
EYE SONDE MEASURED 1004MB WITH 17 KTS SFC WIND
FEEDERBAND CROSSING SE OUTBOUND LEG 70 NM SE OF CTR
COR FOR MAX OUTBOUND FL WIND IN CONVECTIVE BAND
danielw ~ Note:Eye sonde measured 17 knots of wind. This is noted to determine how well the dropsonde was placed. I believe any windspeed below 20 knots is considered an excellent drop.
| hogrunr |
| (Weather Guru) |
| Thu Jul 28 2011 02:50 PM |
|
|
|
Re: Recon
|
Great, thanks Daniel, that's the info I was looking for. It looks like that is just very slightly south and east of the 8 am update from the NHC. Actually has the center sitting right on top of the latest GFDL model run.
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 02:56 PM |
|
|
|
Re: Recon
|
13:49:30Z 24.017N/ 89.917W extrapolated surface pressure 999.5 mb(~ 29.52 inHg)
This looks to be the pressure and wind center here. Lowest pressure, and wind direction switched nearly 180 degrees.
| WeatherNut |
| (Weather Master) |
| Thu Jul 28 2011 03:09 PM |
|
Re: Recon
|
Something else odd was in the latest vortex was an 8C temp difference inside the center and out. Thats 2C higher than Bret had
| hogrunr |
| (Weather Guru) |
| Thu Jul 28 2011 03:11 PM |
|
|
|
Re: Recon
|
Other info that changed in the 10am CDT update...305 (was 300) degree motion...faster at 14mph instead of 10mph previously, and the TS winds extend up to 60 miles (changed from 45 miles previously).
| MichaelA |
| (Weather Analyst) |
| Thu Jul 28 2011 03:11 PM |
|
|
|
Re: Recon
|
Quote:
13:49:30Z 24.017N/ 89.917W extrapolated surface pressure 999.5 mb(~ 29.52 inHg)
This looks to be the pressure and wind center here. Lowest pressure, and wind direction switched nearly 180 degrees.
That puts the center very near the north edge of the convection, so this looks like it may be a tilted system with the mid-level CoC to the south of the surface center.
| WesnWylie |
| (Weather Guru) |
| Thu Jul 28 2011 03:16 PM |
|
Re: Recon
|
Quick question: With a tilted system (displaced mid-level circulation), aside from a re-developing/re-locating LLC, is there anyway for it to become vertically stacked?
Quote:Quote:
13:49:30Z 24.017N/ 89.917W extrapolated surface pressure 999.5 mb(~ 29.52 inHg)
This looks to be the pressure and wind center here. Lowest pressure, and wind direction switched nearly 180 degrees.
That puts the center very near the north edge of the convection, so this looks like it may be a tilted system with the mid-level CoC to the south of the surface center.
|
Ed Dunham
|
| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Thu Jul 28 2011 03:45 PM |
|
Re: Recon
|
Note that the NHC Discussion Bulletin expects the northerly wind shear to remain over the system until landfall, so the short answer regarding a vertically stacked system is 'not very likely'. That is the same reason, along with continued entrainment of drier air from the west, that hurricane intensity is not very likely as well.
ED
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 03:51 PM |
|
Re: Recon
|
Recon is finding the strongest winds away from the center, it recently found a 50 knot flight level wind. Likely means Don will strengthen a little more, but likely not too much more than it is now.
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 04:02 PM |
|
|
|
Re: Recon
|
Quote:
Something else odd was in the latest vortex was an 8C temp difference inside the center and out. That's 2C higher than Bret had
Thanks, I missed that.
That could be significant. Shows the system is beginning to act more like a vacuum.
Thought for the Mets. ULL to the east gives Don a northerly upper level wind flow on the eastern side of the storm. AND ULL to the west gives Don a southerly wind flow on the western side of the storm.
Increasing the vorticity?? in the upper levels??
Visible satellite photos are still showing the arcs of cumulus to the NW of DON. Suggestive of no lower level shear.
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 04:27 PM |
|
|
|
Re: Recon
|
Remarks Section:
Maximum Flight Level Wind: 52kts (~ 59.8mph) in the northeast quadrant at 15:26:00Z
Latest Eye dropsonde is indicating 1005mb (29.68 inHg).
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 28th day of the month at 16:15Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 303)
Storm Number & Year: 04L in 2011
Storm Name: Don (flight in the North Atlantic basin)
Mission Number: 2
Observation Number: 11
A. Time of Center Fix: 28th day of the month at 15:48:40Z
B. Center Fix Coordinates: 24°15'N 90°19'W (24.25N 90.3167W)
B. Center Fix Location: 396 miles (638 km) to the S (182°) of New Orleans, LA, USA.
C. Minimum Height at Standard Level: 1,458m (4,783ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 45kts (~ 51.8mph)
E. Location of the Estimated Maximum Surface Wind: 86 nautical miles (99 statute miles) to the NE (48°) of center fix
F. Maximum Flight Level Wind Inbound: From 150° at 52kts (From the SSE at ~ 59.8mph)
G. Location of Maximum Flight Level Wind Inbound: 70 nautical miles (81 statute miles) to the NE (48°) of center fix
H. Minimum Sea Level Pressure: 1005mb (29.68 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 18°C (64°F) at a pressure alt. of 1,524m (5,000ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 24°C (75°F) at a pressure alt. of 1,524m (5,000ft)
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: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile
Remarks Section:
Maximum Flight Level Wind: 52kts (~ 59.8mph) in the northeast quadrant at 15:26:00Z
| berrywr |
| (Weather Analyst) |
| Thu Jul 28 2011 04:29 PM |
|
|
Re: Recon
|
This is my first post on the website this season so let me first say hello to everybody. I've looked at the new 12Z package and read everybody's post as of noon ET.
The shear over the storm is currently between 10 & 15 knots from the north and northeast with less than 5 knots in a generally north to south axis just ahead of its track. The amount of shear is not enough to impose any strengthening issues at this time.
Water vapor imagery shows relatively dry air along the track and I did look at the most current dry air imagery from CIMMS and there is dry air indicated to the west and less so to the NW of the storm and particularly over land where almost the entire state of TX is experiencing an "Exceptional" drought.
As per NHC, the models are split; half along a NW track, the other half more west.
The vortex structure; it is in fact not aligned and as satellite imagery indicates...it's not too well put together and what appears as the center on satellite is the mid-level center displaced from the surface which is to the northeast under convection.
Not to stray too much from what I posted over on the Flhurricane FaceBook page...Don may become a minimum hurricane but it's greatest benefit is for it to be a strong Tropical Storm and it's bands to gradually open outward as it spirals downward following landfall and provide the beneficial rainfall TX needs.
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 04:49 PM |
|
|
|
Re: Recon
|
Thanks, Bill.
Last drop indicates the warm air is indeed being ingested into the Center.
843mb 23.0°C (73.4°F) near 5000 feet__Dew Point Approximately 9°C (48°F) 41% Humidity
1005mb 28.2°C (82.8°F) (Surface)__Dew Point 27.4°C (81.3°F) 95% Humidity
| Fairhopian |
| (Weather Watcher) |
| Thu Jul 28 2011 05:25 PM |
|
Re: Recon
|
If the low-level center were to eventually align with the mid-level center (say later today), would we likely be able to actually see an eye, and would that eye likely be the size of the current mid-level center as it appears now? If so, would an eye that large tend to steer the storm in a more polar direction?
|
Ed Dunham
|
| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Thu Jul 28 2011 05:33 PM |
|
Re: Windshear
|
While the near-term shear level is low and by itself would not hinder intensification, as noted above, the verticle displacement of the current cyclone is considerable - probably around 70NM between the low-level and high-level circulation centers. This displacement with height to the south would take quite some time to vertically align. Even if the dry air was not a factor it would be difficult for the system to have enough time to align in the vertical prior to landfall.
Its worth noting that the windshear is expected to increase considerably (admittedly from a GFS product) between tonight and Friday morning (time-sensitive link) although the near-shore windshear should be lower:
UNISYS 36hr Shear Forecast
ED
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 06:12 PM |
|
|
|
Re: Windshear
|
Visible below is somewhat centered on the LLC. Low Level Center. LLC can be imagined by locating the outer bands/ arcs at the surface.
The second photo is the enhanced IR image with a CHT, Convective Hot Tower developing near where the LLC should be. CHT is near the green blob. Which is the cauliflower looking cloud in the middle of the upper photo.
| WesnWylie |
| (Weather Guru) |
| Thu Jul 28 2011 07:33 PM |
|
Re: Windshear
|
The blow-up near the LLC continues to grow. Don has begun to look more like a Tropical Storm over the last hour or so. It'll be interesting to see what the next RECON flight reports. By the way, the latest BAM models have tightened up and show a landfall between Brownsville and Corpus Christi.
5:10 PM CDT Update: Correct me if I am wrong guys, but is the latest RECON reporting winds over 60 mph with Don? (Source: http://tropicalatlantic.com/recon/) Time: 21:56 UTC
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 10:12 PM |
|
Re: Windshear
|
There may be a center relocation coming fo Don, a few points south, closer to the convection, which would give it another shot to intensify some, but also move the forecast track further south.
That entire recon report is suspect, the rainfall rate was a bit too crazy too.
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 10:21 PM |
|
Re: Windshear
|
Then again, recon was in the area of this possible hot tower.
So it's definitely something to verify first. If this sustains, then that center reformation may really be occurring, and things change a bit. Not too alarming yet, but it would bring the track further south than is currently in the forecast.
|
danielw
|
| (Moderator) |
| Thu Jul 28 2011 10:28 PM |
|
|
|
Don
|
I see quite a bit of outflow around Don. Not bad for a suppressed/ squeezed cyclone.
I don't know how much the outflow will assist in Don intensifying.
It also indicates the wind shear is lightening up in the area of Don.
Oop, Sorry about that Mike i didn't know you were posting. Image removed... See Mike's above.
| cieldumort |
| (Moderator) |
| Thu Jul 28 2011 10:35 PM |
| Attachment |
|
|
Re: Windshear
|
In regards to Don re-centering within deep convection, here is a screen shot (Google Earth) of the latest recon mission, clearly showing the surface center now aligning itself much more with the deepest convection, and likely as well, with the mid-level circulation.
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 11:00 PM |
|
Re: Windshear
|
A second recon plane is en route to Don now, the NOAA (NOAA2) plane is the one with the high wind reading, the Air force one (307) is about halfway to Don now. It'll be interesting to see if there was anything to it. It definitely caught my eye once I double checked it with satellite.
A few more passes, along with the air force plane, to confirm this will tell a lot.
|
Ed Dunham
|
| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Thu Jul 28 2011 11:15 PM |
|
Re: Intensification
|
Upper level outflow does seem to be improving - to the west. Will be interesting to see if NHC changes anything with the Intermediate update. Probably just wait until the 11pm when they will have more recon data to work with.
ED
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 11:22 PM |
|
Re: Intensification
|
The noaa recon vortex message puts the center at 24.2°N 91.4°W, but the winds only around 35, pressure at 1004, but only 40mph flight level winds.
| berrywr |
| (Weather Analyst) |
| Thu Jul 28 2011 11:29 PM |
|
|
|
Re: Windshear
|
28/2329Z - I looked at the latest CIMMS Wind Shear Analysis and Don is now between an area of winds from the north between 5 and 10 knots, not 10 and 15 knots. Movement of Don over the past several hours is just north of due west and I don't see anything in the model data to suggest otherwise. Don is situated under a 200mb upper ridge axis with an inverted trough to it's NE-E-SE and a closed upper low to its west near the tip of Baja California and a mid to upper level upper ridge over the SE USA. Strength of the SE USA upper ridge supports a continued west to west-northwest movement. The more southerly track is not good news for areas in an exceptional drought but those north and east of the track will see beneficial rainfall.
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 11:44 PM |
|
Re: Windshear
|
Official 8PM position is 24.7N 91.8W, the NHC in the advisory considered it a westward jog. More data from the planes coming later should be interesting.
Also the Central Atlantic wave (no invest yet) has a 20% chance for development over the next 48 hours, so we may go from Don right into tracking another system.
|
MikeC
|
| (Admin) |
| Thu Jul 28 2011 11:53 PM |
|
Re: Windshear
|
NOAA plane is sending back 996.1 for pressure readings on this pass. We may be in for a bit of a boom with Don tonight. Hopefully the airforce plane entering shortly can verify this.
|
MikeC
|
| (Admin) |
| Fri Jul 29 2011 12:17 AM |
|
Re: Windshear
|
The airforce plane just found a 995.4mb pressure. Pretty much verifies what the NOAA plane found. I'd bet on a special statement from the NHC soon.
|
MikeC
|
| (Admin) |
| Fri Jul 29 2011 12:31 AM |
|
Re: Windshear
|
Official vortex message is 999mb from the Airforce plane, probably not enough for a special statement, but should be interesting to see what occurs at the 11PM (10PM CDT) Advisory.
| typhoon_tip |
| (Meteorologist) |
| Fri Jul 29 2011 12:32 AM |
|
Re: Windshear
|
Quote:
Official 8PM position is 24.7N 91.8W, the NHC in the advisory considered it a westward jog. More data from the planes coming later should be interesting.
Also the Central Atlantic wave (no invest yet) has a 20% chance for development over the next 48 hours, so we may go from Don right into tracking another system.
I was considering the possibility that this was a center recapture/reposition as causal to that apparent jog.
Impressively cold persisting quasi-CDO feature, most likely attributed to the fact that the system is currently passing close a region of very high oceanic heat content - with significant thermocline depth as well. This is providing a source of high fuel input that is compensating for any dry air impacts, as well.
So long as we have a TC with a closed circulation, quick pressure falls would likely have to occur given to these powerfully sustaining updrafts as evidenced by IR channels. Most guidance keeps this rather pedestrian; let us hope that is verified. We have seen in the past that pretty satellite presentations are not always confirmed. My personal hope for this was that a pedestrian system would make its way into interior TX and eventually get caught up in the monsoonal flow into OK and other areas that are parched dry and in severe drought.
Currently the wind overlay at TPC, as coarse as it may be, is indicating that the region of impacting NNE shear is bypassing now to the east as the TC moves away; that may also be helping said recapture scenario because the middle and upper level turrets are no longer leaning away from the llv eddy. Fascinating.
|
MikeC
|
| (Admin) |
| Fri Jul 29 2011 02:12 AM |
|
Re: Windshear
|
The good news is that it looks like the pop of intensification has settled to around 999mb, at least in the last few passes, motion is west northwest after the recenter/jog, etc. And it looks as if the Tropical Storm warnings will stand. We'll see at 11 though.
|
danielw
|
| (Moderator) |
| Fri Jul 29 2011 02:18 AM |
|
|
|
Re: Windshear
|
It appears that the difference in the NOAA and the Air Force dropsonde pressure reading is 4 millibars.
If I'm reading the drops correctly the NOAA drop recorded 1000mb -41m (-135 ft).
USAF drop reported 1000mb -5m (-16 ft)
135ft - 16ft = 119ft divided by 33.4 constant equals 3.56 or 4 millibars.
One millibar is roughly 33.4 feet or one atmosphere if you are a diver.
As to which one is more correct. I don't know. They both were dropped in a windy area so it appears that they may not have sampled the lowest pressure.
I am not a Met, but the preference for dropsondes is to be in an area with less than 20 knot winds. If my memory serves me correctly. I'll double check.
|
danielw
|
| (Moderator) |
| Fri Jul 29 2011 02:37 AM |
|
|
|
11 PM
|
They are going with 50 mph and 998mb for the 11 PM Advisory.
|
Ed Dunham
|
| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Fri Jul 29 2011 03:33 AM |
|
Re: Pressure
|
As noted in Mike's latest Main Page Update, Don is weakening a bit and the latest Vortex reports a pressure of 1002MB. I think that the difference in the drops were that they were flying at night while aiming for a small center - and somebody missed!
ED