Not a trace of Don; What's next?

By: Dr. Jeff Masters , 19:41 GMT le 30 juillet 2011

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Don is dead

Tropical Storm Don, the fourth named storm of the 2011 season, made landfall near Baffin Bay, Texas yesterday evening around 10pm CDT in less-than-grand fashion. The storm was looking very weak for the 24 hours before landfall, but fizzled rapidly after landfall, and by early Saturday morning, there was barely a trace of the storm to show that it even existed in the first place.

NHC Hurricane Specialist Eric Blake probably said it best in this mornings 5am EDT discussion on the storm:

THE DON IS DEAD. THE CYCLONE LITERALLY EVAPORATED OVER TEXAS ABOUT
AS FAST AS I HAVE EVER SEEN WITHOUT MOUNTAINS INVOLVED. DON HAS NO
CONVECTION...MEAGER RAINFALL...AND ONLY A SLIGHT SIGNATURE IN
SURFACE OBSERVATIONS AND RADAR DATA. THEREFORE...THIS IS THE LAST
ADVISORY ON THIS SYSTEM.


Figure 1. Total precipitation accumulation for the storm, estimated by radar.

The heaviest rainfall was falling south of the storm's center yesterday, so it wasn't surprising that Brownsville saw the most rain, 0.63 inches. KBRO also recorded 18 mph wind gusts. But to the north of the center, where many of the media were located, not a drop of rain fell. Corpus Christi saw zero inches of rain, but did record gale-force wind gusts (39 mph). Harlingen, near Baffin Bay, and close to where the center made landfall, saw 0.20 inches of rain and 18 mph wind gusts. This storm did very, very little to relieve any drought conditions in Southern Texas. And so it continues.

What's next: Invest 91L continues to impress

Invest 91L, which is located near 12°N 48°W in the central Atlantic, continues to impress today, and has shown signs of more organization over the past 24 hours. 91L will probably develop into a tropical cyclone before it reaches the Lesser Antilles, so residents of these islands should remain watchful and prepared. Satellite loops show not only organized thunderstorm activity, but also the makings of a surface circulation. Something this wave has working against it right now is dry air—there's a large mass of Saharan air on the north and east sides of the system, which could at least prevent significant intensification. Also, University of Wisconsin CIMSS analysis shows some strong wind shear (30-40 knots) to the north of the wave. However, I don't expect this to prevent development of the wave. Wind shear out ahead of the system is relatively low (5-15 knots). Moisture is plenty high within the system, and sea surface temperatures are warm and toasty (28°C+) and will only get warmer as 91L moves west into the Caribbean.


Figure 2. Infrared satellite of invest 91L taken at 1:15pm EDT today.

Forecast for 91L
Most of the reliable forecast models (GFS, CMC, FIM, and the ECMWF) have come to agree that 91L will develop, however, they differ on how long-lived that will be. Some of the models are suggesting it will be a short-lived tropical cyclone, not making it out of the Caribbean alive, and some suggest that it will hold together and intensify as it moves north of the Caribbean islands. The forecast track for the system will most likely be to the northwest through the Caribbean, at which point it will take a northeast turn near the Bahamas, never reaching the U.S. coast. HWRF agrees with this track (and also brings the system to category 2 strength by August 3rd). However, there is still some uncertainty that the system could track west, south of the Caribbean islands, and potentially into the Gulf of Mexico. However, none of the models that suggest this solution actually show that the wave will be a tropical cyclone at that point.

The National Hurricane Center is giving this wave an 80% chance of developing into at least Tropical Depression Five over the next 48 hours. Chances are we will see Emily out of this system. A Hurricane Hunter mission is scheduled for tomorrow at 2pm EDT, but I wouldn't be totally surprised to see them call this system this evening, given the threat to the Lesser Antilles.

Watching a northwest Caribbean disturbance

A broad area of disturbed weather is producing some heavy thunderstorms in the northwest Caribbean, southeast of the Yucatan Peninsula. Little to no low-level circulation exists with this feature, and none of the models are picking up on it. The Hurricane Center has "blobbed" this item (as I like to say) with a "near 0%" chance of developing over the next 48 hours. This disturbance could cause major flooding in the region given the amount of thunderstorm activity, and predictability for systems like this (potential Bay of Cempeche tropical cyclones) is very low. Models have a short lead time on development, and they spin up very fast once they enter the Bay of Campeche given the favorable topography of the land surrounding it. The difference between this system, though, and one like Arlene, is that there is very, very little low level circulation already present. Pre-Arlene was a bit more organized before it crossed the Yucatan, and so it's hard to imagine that this disturbance will be able to hold together, should it get that far.

If 91L develops, I'll be back tomorrow with a post.

Angela

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Anyone knows whats up with Recon?
Member Since: Posts: Comments:
Quoting Dakster:
P451 - They are flying a shoe pattern now?
you took the words right out of my mouth, lol, what a neat shape for a flight pattern!
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3448. SLU
384

WHXX01 KWBC 311905

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS NATIONAL HURRICANE CENTER MIAMI FL

1905 UTC SUN JUL 31 2011



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



DISTURBANCE INVEST (AL912011) 20110731 1800 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

110731 1800 110801 0600 110801 1800 110802 0600



LAT LON LAT LON LAT LON LAT LON

BAMS 13.5N 52.8W 14.1N 55.1W 14.8N 57.4W 15.4N 59.7W

BAMD 13.5N 52.8W 14.2N 55.3W 14.7N 57.5W 15.1N 59.6W

BAMM 13.5N 52.8W 14.0N 55.0W 14.4N 57.3W 14.9N 59.4W

LBAR 13.5N 52.8W 13.9N 55.2W 14.5N 57.8W 14.9N 60.3W

SHIP 30KTS 38KTS 47KTS 56KTS

DSHP 30KTS 38KTS 47KTS 56KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

110802 1800 110803 1800 110804 1800 110805 1800



LAT LON LAT LON LAT LON LAT LON

BAMS 16.2N 62.1W 17.8N 66.9W 19.7N 71.7W 21.1N 75.1W

BAMD 15.7N 61.4W 17.9N 64.7W 21.1N 67.8W 23.2N 70.5W

BAMM 15.5N 61.6W 17.3N 65.8W 19.6N 69.8W 21.4N 72.8W

LBAR 15.5N 62.7W 17.6N 67.1W 21.4N 70.4W 23.9N 72.7W

SHIP 65KTS 75KTS 77KTS 75KTS

DSHP 65KTS 75KTS 70KTS 68KTS



...INITIAL CONDITIONS...

LATCUR = 13.5N LONCUR = 52.8W DIRCUR = 285DEG SPDCUR = 12KT

LATM12 = 12.9N LONM12 = 50.3W DIRM12 = 282DEG SPDM12 = 12KT

LATM24 = 12.4N LONM24 = 47.9W

WNDCUR = 30KT RMAXWD = 60NM WNDM12 = 30KT

CENPRS = 1007MB OUTPRS = 1010MB OUTRAD = 150NM SDEPTH = M

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN

Member Since: 13 juillet 2006 Posts: 12 Comments: 4859
Quoting Tazmanian:



old


You would be incorrect. That's the new position analyzed today at 2PM EST. Look at the time stamp again.
Member Since: Posts: Comments:
Quoting Tazmanian:



old


not old, 18Z on the 31st
Member Since: 10 Mars 2010 Posts: 1 Comments: 7367
Invest91L isn't going anywhere!!!
Member Since: 30 juillet 2010 Posts: 0 Comments: 286
Quoting nrtiwlnvragn:
AL, 91, 2011073118, , BEST, 0, 135N, 528W, 30, 1007, LO, 34, NEQ, 0, 0, 0, 0, 1010, 150, 60, 0, 0, L, 0, , 0, 0, INVEST, M,



old
Member Since: Posts: Comments:
3443. SLU
Quoting nrtiwlnvragn:
AL, 91, 2011073118, , BEST, 0, 135N, 528W, 30, 1007, LO, 34, NEQ, 0, 0, 0, 0, 1010, 150, 60, 0, 0, L, 0, , 0, 0, INVEST, M,


It looks like they're still tracking the "old" center but it seems the one near 13n 57w is becoming more dominant.
Member Since: 13 juillet 2006 Posts: 12 Comments: 4859
3442. ackee
when will recon finish there mission
Member Since: 15 juillet 2008 Posts: 0 Comments: 1346
3441. Dakster
P451 - They are flying a shoe pattern now?
Member Since: 10 Mars 2006 Posts: 0 Comments: 10034
Quoting sunlinepr:
Invezgs 91L is starting show who is the boss...
Member Since: 14 juillet 2008 Posts: 0 Comments: 246
It seems like all the storms thus far are having issues getting going. Be it shear, lack of convergence or divergence,dry air, sure not like the Pacific storms,who get going and all become Hurricanes.

Was hopeful that Emily would form today, to match the Pacific Basin and have the "E" storms form on the same day! Is their a record to check for that info?
Member Since: Posts: Comments:
Right, I'm getting too impatient, I'll take a break for an hour and come back to see what's happened.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
AL, 91, 2011073118, , BEST, 0, 135N, 528W, 30, 1007, LO, 34, NEQ, 0, 0, 0, 0, 1010, 150, 60, 0, 0, L, 0, , 0, 0, INVEST, M,
Member Since: 23 septembre 2005 Posts: 14 Comments: 10875
3435. GHOSTY1
Quoting kylejourdan2006:
91L has rather healthy looking inflow bands...



HH will almost certainly find a low-level circulation in the system on the right. Satellite loops are showing the left-ward activity is being influence by 91L...rather than vise-versa...



I agree, if u could, can you point out where the llc is believed to be? Thanks
Member Since: 25 juillet 2011 Posts: 0 Comments: 453
I'm gonna' say the NHC doen't go for this split system thought. They'll call it a TD or TS at 5PM with a center in the middle of the eastern half, the real low.
Member Since: Posts: Comments:
re 3396. Thanks a lot for sharing a screenshot, P451. I'm not at my own computer so I can't check out the Google Earth recon files. The two missions make some sense to me, now that I've seen the pics.

I'm off now, bbl, hopefully when new recon data and a new blog is out.
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3430. KEEPEROFTHEGATE (Mod)
POSS T.C.F.A.
XL/XX/INV91
MARK CENTER OF IMAGE
15.55N/55.55W
Member Since: 15 juillet 2006 Posts: 169 Comments: 53296
Quoting CybrTeddy:
Okay, what's up with the recon? Obs are coming in very scarce.


No idea. Haven't seen any since they were at 54.7W
Member Since: Posts: Comments:
91L has rather healthy looking inflow bands...



HH will almost certainly find a low-level circulation in the system on the right. Satellite loops are showing the left-ward activity is being influence by 91L...rather than vise-versa...

Member Since: 18 juillet 2006 Posts: 32 Comments: 1521
3427. JRRP
Quoting cchsweatherman:
The situation seems to have gotten more complex and uncertain this afternoon as there is great uncertainty at this time about a defined circulation center for Invest 91L. The separation of the tropical wave last night from the system made things more complicated and more elongated. I have to agree now that, until we seem some coalescing of the system into one defined circulation, we will likely not see any further classification beyond invest status.

On another note, its really difficult to follow the computer models without a defined circulation and since the system has continued moving westward throughout the day, which goes against what the models were suggesting would happen with a more WNW track.

good point... very good
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Looks like 91L has a mirror image; Twin Invests.
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ECM has Muifa running up the entire NE coast of China while apparently maintaining major hurricane strength. It then smacks Beijing head on. The ramifications are too diverse to consider. No more money for our debt. World depression and or war. No more cheap toys for the kids at Wal-Mart. No more drywall because they will need it.
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Quoting 7544:
throw the models out the first blob is the real 91l


you mean the wave in front lol
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Is that thing going to develop before the mountainous islands rip it to shreds?
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Okay, what's up with the recon? Obs are coming in very scarce.
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Quoting stormpetrol:
Something not right with Recon!

Yes indeed - google earth has more data than tropicalatlantic.com and then sometimes vice-versa - See the data and then it disappears.... Wonder if they have been hacked.
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3419. barbamz
Quoting cchsweatherman:
The situation seems to have gotten more complex and uncertain this afternoon as there is great uncertainty at this time about a defined circulation center for Invest 91L. The separation of the tropical wave last night from the system made things more complicated and more elongated. I have to agree now that, until we seem some coalescing of the system into one defined circulation, we will likely not see any further classification beyond invest status.

On another note, its really difficult to follow the computer models without a defined circulation and since the system has continued moving westward throughout the day, which goes against what the models were suggesting would happen with a more WNW track.

Sounds reasonable IMO.
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3418. GHOSTY1
the BAMM BAMD and HWRF models from the wunderground site seem kinda of ominous to me because with the only land interaction being puerto rico and going in between Cuba and Florida seems to me that it would give possibly "Emily" alot of time to strengthen being over water with little land interaction, imo.
Member Since: 25 juillet 2011 Posts: 0 Comments: 453
3417. 7544
throw the models out the first blob is the real 91l
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Just a thought here...

Should both 'pieces' of 91L start to combine, to form a larger circulation, the system would obviously stay weaker for longer. This could well result in a more westward path, into the central Caribbean, where shear is currently low, and with all that energy something pretty big could spin up. This may very well not happen, just something to keep an eye on.
Member Since: Posts: Comments:
Quoting Patrap:
I believe,,and its my opine only,, is that we have a Mean center that has Bi-lobed into 2 Entity's..one west,and one East.

One has to dominate for the Invest to gain any classification or organization.



In other words,,its a muddy puddle with the future to shake out downstream in time.

Patience,,..its da tropics.
water vapor show Invest 91L healthy and bouth systems consolidate in one...
Member Since: 14 juillet 2008 Posts: 0 Comments: 246
Quoting Tazmanian:
wish is the real 91L lol


Will the real 91L Please Stand Up
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Quoting Dakster:
Anyone see the weather reporter get shot on live TV?

It was with a BB gun and the kids were caught...

Link


Didn't see it but I bet it's funny. reminds me of a song I heard

I'd like to shoot you in the a** with a BB gun,
Lay there in the tall grass and laugh at what I done,
put a blood blister upon each bun,
I'd like to shoot you in the a** with a BB gun
Member Since: Posts: Comments:
Quoting weatherh98:


patience


And the ECMWF develops it too..
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The situation seems to have gotten more complex and uncertain this afternoon as there is great uncertainty at this time about a defined circulation center for Invest 91L. The separation of the tropical wave last night from the system made things more complicated and more elongated. I have to agree now that, until we seem some coalescing of the system into one defined circulation, we will likely not see any further classification beyond invest status.

On another note, its really difficult to follow the computer models without a defined circulation and since the system has continued moving westward throughout the day, which goes against what the models were suggesting would happen with a more WNW track.
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wish is the real 91L lol
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3408. Dakster
Quoting HurricaneHunterJoe:
looks like a face with phsyc glasses


Floodman would be proud...
Member Since: 10 Mars 2006 Posts: 0 Comments: 10034
Quoting Dakster:
So could both systems consolidate into one humongous system?

IMHO, more than likely one will dominate and absorb the other.


You're more than likely right. The dominant circulation...which appears at the time to be the one on the right will absorb the shower activity on the left...especially because the system to the left doesn't appear to possess an area of low pressure to develop into anything...
Member Since: 18 juillet 2006 Posts: 32 Comments: 1521
Quoting FrankZapper:
Maybe ECM Is right after all. 91 will be a fizz storm.


patience
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Quoting ryang:


Interesting indeed:

looks like a face with phsyc glasses
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3404. TxKeef
I know it's hard to say, but what is the general consensus on development before it reaches the Dominican? My mom just flew out today to be there for a week on vacation. It still seems to be having some problems with dry air by the looks of the outflow boundaries on sat loops.
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Something not right with Recon!
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Maybe ECM Is right after all. 91 will be a fizz storm.
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3401. ackee
IF 91L remains weak then would be moving throught the carrb seem like 91L centre has relocated futher south this system like the joker
Member Since: 15 juillet 2008 Posts: 0 Comments: 1346

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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