93L near tropical depression strength

By: Dr. Jeff Masters , 2:31 PM GMT on June 25, 2010

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The first tropical depression of the 2010 Atlantic hurricane season appears imminent in the Western Caribbean, as the areal coverage and intensity of heavy thunderstorm activity associated with the tropical wave (Invest 93L) continue to increase. The storm has developed a surface circulation near 16.5N, 82.5W at 8am EDT, about 100 miles northeast of the Nicaragua/Honduras border. This is far enough from land that development will be slowed only slightly. Satellite loops show a poorly organized system, with only a modest amount of heavy thunderstorm activity near the center. However, the developing storm is affecting the weather across the entire Western Caribbean, and bands of heavy thunderstorms are quickly building over a large region. Pressures at ground stations and buoys all across the Western Caribbean have been falling significantly over the past day (Figure 2.) Water vapor satellite loops show that moist air surrounds 93L, and there is not much dry air to slow down development. There is an upper-level high pressure system a few hundred miles west of 93L, and the clockwise flow air around this high is bringing upper-level winds out of the northwest of about 10 - 15 knots over 93L, contributing to the 10 - 15 knots of wind shear observed in this morning's wind shear analysis from the University of Wisconsin's CIMSS group. Sea Surface Temperatures are very warm, 29 - 30°C. The Madden-Julian oscillation (MJO) currently favors upward motion over the Caribbean, which will act to increase the chances of tropical storm formation this week. The main negative for 93L is a combination of lack of spin and wind shear. Last night's pass of the ASCAT satellite showed a broad, elongated circulation, which will need to tighten up in order for 93L to become a tropical depression. The Hurricane Hunters are scheduled to fly into 93L at 2pm EDT this afternoon to see if a tropical depression has formed.


Figure 1. Morning visible satellite image of the central Caribbean disturbance 93L.


Figure 2. Combined plot of wind speed, wind gusts, and pressure at buoy 42057 in the Western Caribbean. Pressure (green line) has fallen significantly over the past two days, and winds are beginning to increase.

Forecast for 93L
The greatest risk from 93L to the Western Caribbean will be heavy rainfall, and the nation most at risk is Honduras. The counter-clockwise flow of air around 93L will bring bands of rain capable of bringing 4 - 8 inches of rain to northern Honduras over the next two days. Heavy rains of 3 - 6 inches can also be expected in northeast Nicaragua, Cuba, Belize, the Cayman Islands, and Mexico's Yucatan Peninsula. The storm is moving west-northwest at about 10 mph, and this motion is expected to gradually slow over the next five days to about 6 mph. I expect that by tomorrow, 93L should be closer to being directly underneath the upper level high pressure system to its west, which would act to lower wind shear and provide more favorable upper-level outflow. NHC is giving 93L a 70% chance of developing into a tropical depression by Sunday morning, which is a reasonable forecast. The storm will probably be a tropical depression or tropical storm with 40 mph winds when it moves over Mexico's Yucatan Peninsula on Sunday. The storm will probably spend a day or so over the Yucatan, resulting in significant weakening. Once 93L emerges over the Gulf of Mexico, it will take the storm 24+ hours to recover its strength.

A trough of low pressure is expected to swing down over the Eastern U.S. on Monday. If this trough is strong enough and 93L develops significantly, the storm could get pulled northwards and make landfall along the northern Gulf of Mexico coast. This is the solution of the GFDL and HWRF models. If 93L stays weak and/or the trough is not so strong, the storm would get pushed west-northwestwards across Mexico's Bay of Campeche and make landfall along Mexican coast south of Texas, or in Texas. This is the solution of the NOGAPS, ECMWF, and Canadian models. A likely landfall location is difficult to speculate on at this point, and the storm could hit virtually anywhere along the Gulf of Mexico coast given the current uncertainty in its development. The amount of wind shear in the Gulf of Mexico next week is also highly uncertain. There is currently a band of high shear near 30 knots over the Gulf. The GFS model predicts that this band of high shear will lift northwards, keeping low wind shear over the Gulf next week. However, the ECMWF model keeps high shear entrenched over the Gulf of Mexico, which would make it unlikely 93L could intensify into a hurricane. In summary, I give 93L a 60% chance of eventually becoming Tropical Storm Alex, and 10% chance of eventually becoming a hurricane.

Elsewhere in the tropics
A tropical wave a few hundred miles northeast of the northernmost Lesser Antilles Islands is producing a modest amount of heavy thunderstorm activity. This system was designated Invest 94 by NHC this morning, and is passing beneath a trough of low pressure that is generating 30 - 40 knots of wind shear. However, by Sunday, the storm will be in a region of much lower wind shear, and NHC is giving the storm a 10% chance of developing into a tropical depression by Sunday morning. We do have one model, the GFS, which develops the system early next week. The GFS model takes the storm to the northwest and then north, predicting it will be very close to Bermuda on Tuesday.


Figure 3. Hurricane Celia as a Category 4 storm at 20:55 UTC Thursday, June 24, 2010, as captured by NASA's MODIS instrument.

Impressive Hurricane Celia hits Category 5
The first Category 5 hurricane in the Northern Hemisphere this year is Hurricane Celia in the Eastern Pacific. Celia's 160 mph winds make it tied with Australia's Tropical Cyclone Ului as the strongest tropical cyclone in the world so far in 2010. Celia has likely peaked in intensity, and is not expected to threaten any land areas.

Wind and ocean current forecast for the BP oil disaster
East to southeast winds of 5 - 15 knots will blow in the northern Gulf of Mexico today through Tuesday, according to the latest marine forecast from NOAA. The resulting weak ocean currents should push the oil to the west and northwest onto portions of the Louisiana and Alabama coasts, according to the latest trajectory forecasts from NOAA and the State of Louisiana. I would expect Mississippi to have its most serious threat of oil yet early next week as these winds continue. The longer range outlook is uncertain, and will depend upon what 93L does.

Resources for the BP oil disaster
Map of oil spill location from the NOAA Satellite Services Division
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

Jeff Masters

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2679. cg2916
Quoting CybrTeddy:
TD 1's likely nearing TS at this point, with a pressure of 1005 mb that's fairly deep for a TD.


1002.9 MB.
Member Since: December 21, 2007 Posts: 13 Comments: 3046
2678. centex
Quoting kmanislander:
Levi or anyone who knows the answer:

What is the timing on the trough that is supposed to swing down across the N GOM ?.

If this system hangs around, deepens and takes its time moving off to the NW the timing on the trough will be critical as to potential future track to points due N.
Not expert on this but this has been noted as extreme anti climatology and local NWS office questions it.
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Quoting Snowlover123:


I heard that the Navy is classifying this as TD 1. Can anyone confirm this?

-Snowlover123


Navy does not classify systems in the Atlantic, East and Central Pacific. NHC for Atlantic and East Pacific. CPHC for Central Pacific.
Member Since: September 23, 2005 Posts: 15 Comments: 11342
Quoting CybrTeddy:
TD 1's likely nearing TS at this point, with a pressure of 1005 mb that's fairly deep for a TD.


Recon just found 1003mbs
Member Since: June 9, 2007 Posts: 4 Comments: 15950
Quoting MiamiHurricanes09:
That looks like it's a little more than a tropical depression. I'm eager to see what is the minimum pressure that they put on the advisory.



me too
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Quoting winter123:

Sorry. Just popped on for a minute. So it begins...


Its cool, sorry if what I said was disrespectful.
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Quoting cg2916:


OMG, you're right!


Oh wow...!
Member Since: July 30, 2007 Posts: 76 Comments: 4063
2672. Levi32
There it is finally.

Member Since: November 24, 2005 Posts: 635 Comments: 26700
Quoting Levi32:


The GFS switches the steering to SSE as soon as 48 hours but doesn't really dig the trough in until 96 hours.

The ECMWF also has it digging in by 96 hours but of course doesn't have it recurving TD 1. It proclaims a much stronger ridge over the GOM between TD 1 and the trough.


Thanks. The trough ought not to be a factor but you never know. Would take a prolonged stall in the NW Caribbean.
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Quoting twooks:


Harsh >_>/ Alex's feelings may be hurt :P


Awww. Poor Alex. SAY YOU'RE SORRY TO HIM! :P

-Snowlover123
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Quoting Patrap:
01L

OIL

Otay,...


Topato
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Member Since: June 9, 2007 Posts: 4 Comments: 15950
TD 1's likely nearing TS at this point, with a pressure of 1005 mb that's fairly deep for a TD.
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Quoting CybrTeddy:


Really? Look up, its a TD now. They issued a renumber.

Sorry. Just popped on for a minute. So it begins...
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Quoting Levi32:
We found the center. 1002.9mb.

000
URNT15 KNHC 252145
AF302 01AAA INVEST HDOB 43 20100625
213530 1625N 08324W 9783 00229 0043 +233 +180 197017 019 023 002 03
213600 1626N 08325W 9778 00234 0044 +217 +180 194018 019 033 009 03
213630 1626N 08327W 9782 00228 0044 +205 +180 195016 018 038 018 03
213700 1627N 08328W 9779 00229 0041 +207 +180 186017 020 047 030 03
213730 1628N 08330W 9772 00236 0041 +209 +180 186018 020 041 026 03
213800 1628N 08331W 9785 00223 0041 +212 +180 230008 016 045 024 03
213830 1629N 08333W 9777 00231 0041 +220 +180 310005 009 030 015 00
213900 1629N 08334W 9785 00225 0040 +237 +180 339005 006 999 999 03
213930 1631N 08334W 9765 00238 0038 +239 +180 341006 006 016 005 03
214000 1632N 08334W 9481 00481 0029 +213 +180 340004 006 024 011 03
214030 1634N 08333W 9036 00914 0038 +206 +180 346005 007 999 999 03
214100 1636N 08333W 8606 01350 0054 +168 +168 340004 004 999 999 03
214130 1638N 08333W 8427 01532 0053 +165 +165 346003 004 003 008 00
214200 1640N 08333W 8422 01534 0051 +163 +163 007002 002 005 002 00
214230 1642N 08332W 8440 01515 0054 +159 +159 110002 003 001 003 03
214300 1644N 08332W 8436 01523 0058 +158 +158 109005 006 013 005 03
214330 1646N 08333W 8433 01525 0055 +160 +160 089004 005 006 003 03
214400 1647N 08334W 8420 01537 0045 +174 +174 056008 010 010 005 00
214430 1648N 08336W 8429 01530 0039 +184 +180 055015 017 000 003 00
214500 1649N 08337W 8436 01524 0043 +181 +180 047017 017 000 003 03
$$
That looks like it's a little more than a tropical depression. I'm eager to see what is the minimum pressure that they put on the advisory.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
2662. IKE
Quoting nrtiwlnvragn:


Carefull with the coordinates in the raw data Levi has been posting. They are in degrees, minutes - which are slightly different the lat/lon.


Okay...that goes up to 60...so it's around 16.5N.
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2661. tkeith
Quoting smmcdavid:


I didn't want to say anything, but some people think I'm pretty awesome... lol. True story.
I agree...check yer blog...lol
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I doubt this storm will go to Belize, my bet is from Cozumel to the western tip of Cuba through the Yucatan Channel most likely as a strong TS or even a minimal hurricane, just my opinion of course I sure as heck feel sorry for those folks in the Gulf with the oil as this will only add a big insult to injury.
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2659. amd
Quoting IKE:


It's heading almost due west. It will be over land a good 24 hours. It's moving away from Tampa.


the only chance, IMO, for a landfall east of the texas/louisiana landfall is if the GFS "super" trough actually verifies.

Since this is a developing la nina, and the end of June, I would expect the system to travel through the Yucatan, and have a final landfall anywhere from Tampico to South Padre Island, IMO.

Maybe I am being too hopeful, but I don't think soon to be Alex will affect the oil spill areas.
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Quoting txag91met:

1002.9 is a tropical storm in my book...regardless of the wind field, the wind field will respond quickly to the pressure.


Convection within spiral bands is speeding up and expanding, surface winds are increasing.
Member Since: July 30, 2007 Posts: 76 Comments: 4063
2656. cg2916
Quoting Patrap:
01L

OIL

Otay,...


OMG, you're right!
Member Since: December 21, 2007 Posts: 13 Comments: 3046
Quoting Floodman:


Yeah, we decided to vote you off the island...here are your water wings


LOL!

-Snowlover123
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Quoting winter123:
My gut tells me 93L is not Alex. It will slam into mexico tomorrow and die. May become TD though. Wow @ EPAC too.


Really? Look up, its a TD now. They issued a renumber.
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2653. Michfan
We wont have a good handle on the track of this storm till the next set of model runs imo. Once they have the inputted data from the HH's we should have a much better idea of what is going to happen.
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2652. twooks
Quoting winter123:
My gut tells me 93L is not Alex. It will slam into mexico tomorrow and die. May become TD though. Wow @ EPAC too.


Harsh >_>/ Alex's feelings may be hurt :P
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Quoting charlottefl:
Was pretty close.. :)


1002.9 is a tropical storm in my book...regardless of the wind field, the wind field will respond quickly to the pressure.
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Quoting winter123:
My gut tells me 93L is not Alex. It will slam into mexico tomorrow and die. May become TD though. Wow @ EPAC too.


We already know it's a TD.
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I hope the forecasters can clear all the oil areas fast of this system. A Central or South Texas hit would be great for all of us in the oil affected areas. I think all of us specifically in the FWB-P'Cola-Destin area really don't want this to hit anywhere from the Louisiana border and eastward. That would be disaster for all of us.
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Quoting Michfan:


Its a hurricane enthusiast blog. While none of us wish harm on anyone most of us here are intrigued by the formation of tropical cyclones and the science surrounding them. Get used to it.


If that were the case, there'd be a LOT more interest in Celia, which was Cat 5 this morning, and Darby, which is Cat 3 now. Instead, we're obsessing over an invest that may or may not be a tropical cyclone yet. Because Celia isn't going to hit land, Darby is going to futz around for the next week, and this invest, which may or may not be Alex, could hit the U.S.

It's really myopic and sick, and any claim that people are just in it "because they're interested in hurricane development" is total bull. They're interested in seeing storms in the Atlantic develop and hit land. Otherwise, why so little chatter about two major storms (including a rare Category 5 in June)?
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Quoting IKE:


Still further south.....heading for Belize.


Carefull with the coordinates in the raw data Levi has been posting. They are in degrees, minutes - which are slightly different the lat/lon.
Member Since: September 23, 2005 Posts: 15 Comments: 11342
I am guessing we will slowly clean up and be ready, here near Grand Isle/Port Fourchon. Patrap, you ready in the city?
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2645. Levi32
Quoting Patrap:
01L

OIL

Otay,...


LOL
Member Since: November 24, 2005 Posts: 635 Comments: 26700
Quoting stormpetrol:

Agreed 100%, thats what i'm afraid a slow movement or near stationary gives it time to strengthen and move more NNW in our neck of the woods, we'd be on the bad side of it anyway right front quandrant, wouldn't surprise me to see TS watches go for Grand Cayman.


I don't see it as a threat to us. We would need a front to dig down to the Yucatan to pick it up to the NE for that to happen and we won't see those conditions again until Oct. and Nov.
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Was pretty close.. :)

Quoting charlottefl:
I would put it close to 16.2N 83.4/5 W

Edit: Maybe as high as 16.4 (somewhere in there, it's kinda hard to see)


Quoting Levi32:
We found the center. 1002.9mb.

000
URNT15 KNHC 252145
AF302 01AAA INVEST HDOB 43 20100625
213530 1625N 08324W 9783 00229 0043 +233 +180 197017 019 023 002 03
213600 1626N 08325W 9778 00234 0044 +217 +180 194018 019 033 009 03
213630 1626N 08327W 9782 00228 0044 +205 +180 195016 018 038 018 03
213700 1627N 08328W 9779 00229 0041 +207 +180 186017 020 047 030 03
213730 1628N 08330W 9772 00236 0041 +209 +180 186018 020 041 026 03
213800 1628N 08331W 9785 00223 0041 +212 +180 230008 016 045 024 03
213830 1629N 08333W 9777 00231 0041 +220 +180 310005 009 030 015 00
213900 1629N 08334W 9785 00225 0040 +237 +180 339005 006 999 999 03
213930 1631N 08334W 9765 00238 0038 +239 +180 341006 006 016 005 03
214000 1632N 08334W 9481 00481 0029 +213 +180 340004 006 024 011 03
214030 1634N 08333W 9036 00914 0038 +206 +180 346005 007 999 999 03
214100 1636N 08333W 8606 01350 0054 +168 +168 340004 004 999 999 03
214130 1638N 08333W 8427 01532 0053 +165 +165 346003 004 003 008 00
214200 1640N 08333W 8422 01534 0051 +163 +163 007002 002 005 002 00
214230 1642N 08332W 8440 01515 0054 +159 +159 110002 003 001 003 03
214300 1644N 08332W 8436 01523 0058 +158 +158 109005 006 013 005 03
214330 1646N 08333W 8433 01525 0055 +160 +160 089004 005 006 003 03
214400 1647N 08334W 8420 01537 0045 +174 +174 056008 010 010 005 00
214430 1648N 08336W 8429 01530 0039 +184 +180 055015 017 000 003 00
214500 1649N 08337W 8436 01524 0043 +181 +180 047017 017 000 003 03
$$
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Quoting Snowlover123:


I heard that the Navy is classifying this as TD 1. Can anyone confirm this?

-Snowlover123


Yeah.
invest_RENUMBER_al932010_al012010.ren
Member Since: July 30, 2007 Posts: 76 Comments: 4063
2641. cg2916
Quoting Snowlover123:


I heard that the Navy is classifying this as TD 1. Can anyone confirm this?

-Snowlover123


We've seen a renumber, we have TD 1 with 35 mph winds.
Member Since: December 21, 2007 Posts: 13 Comments: 3046
My gut tells me 93L is not Alex. It will slam into mexico tomorrow and die. May become TD though. Wow @ EPAC too.
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2638. Patrap
Quoting truecajun:


LOL!

y'all have fun. i've got to get some billing reports finished for work:(


Im expecting those TPS reports by 5 .

Member Since: July 3, 2005 Posts: 428 Comments: 129833
Quoting truecajun:
Ok. i'm going to ask a 4th time, forgive me it the other three times show up (i never saw my question post)

yesterday, Dr. Masters said that he did NOT think that 93L, our now TD1, would ever make it to Hurricane strength. Do you think this is still the case?
That's
hard to answer because you're asking someone to give an opinion on what Dr. Master's opinion is. I guess, that seeing as things have progressed about as he expected earlier...his opinion now would be the same that it was then. 10% chance of hurricane.
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2636. fsumet
TD1 1004mb moving west northwest. Still uncertain with track past Yucatan. This was from NHC by the way.
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Quoting Floodman:


LOL...who you, Betty Bada$$?


I didn't want to say anything, but some people think I'm pretty awesome... lol. True story.
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....so we are going to get rain from this storm in South Florida... yup, we were told to watch out for the moisture that might come our way....lol....
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2633. Patrap
01L

OIL

Otay,...
Member Since: July 3, 2005 Posts: 428 Comments: 129833
Quoting CaneWarning:


You are on the wrong blog.


LOL!

y'all have fun. i've got to get some billing reports finished for work:(
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2631. centex
Darn, look away for few minutes and 200 more post.
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There is no way this is just a depression by looking at satellite imagery. The anticyclone is really cranking up organization now that it's better positioned.
Member Since: July 30, 2007 Posts: 76 Comments: 4063
2629. Levi32
Quoting kmanislander:
Levi or anyone who kn wos the answer:

What is the timing on the trough that is supposed to swing down across the N GOM ?.

If this system hangs around, deepens and takes its time moving off to the NW the timing on the trough will be critical as to potential future track to points due N.


The GFS switches the steering to SSE as soon as 48 hours but doesn't really dig the trough in until 96 hours.

The ECMWF also has it digging in by 96 hours but of course doesn't have it recurving TD 1. It proclaims a much stronger ridge over the GOM between TD 1 and the trough.
Member Since: November 24, 2005 Posts: 635 Comments: 26700

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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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