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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179. unf97
Quoting weathermanwannabe:
Invest 94, while firing a good amount of convection, is about to run into a wall of 30-50 knots of sheer and right on the boundry and very close to the TUTT......I would not get too excited about this one at the moment.


Good observation. It is approaching the sheer zone and I highly doubt anything will come out of this invest, but, you never know. We have seen surprises occur out there in the past, so it will be montiored, but no major threat at this time.
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could see bonnie out of 94L.
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Quoting Stormchaser2007:
12z NAM simulated radar reflectivity:



that dont look good
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Quoting Stormchaser2007:
Twins...



Interesting vorticity with 94L. I noticed this area of disturbed weather yesterday, but it was very unimpressive. I didn't see this coming.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting FLWeatherFreak91:
As I was stating earlier for the thousandth time... anticyclones don't automatically make a system clear from shear. Sometimes they cause shear over their own low level systems... plus, many of the models are indicating high levels of shear in the gulf... you don't know for sure that the shear is going to be favorable in the gulf yet.

If you were to read the blog you are posting on, you would have seen that
Exactly. If the system isn't placed directly below the anticyclone it can get shear from the outflow from the anticyclone or upper level ridge.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Twins...

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Very busy week coming.
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I see we have another invest, 94L and the NHC upped 93L slightly to 70% which is reasonable.
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Quoting Enforcer001:

It's called an anticyclone, and lifting of the TUTT.
As I was stating earlier for the thousandth time... anticyclones don't automatically make a system clear from shear. Sometimes they cause shear over their own low level systems... plus, many of the models are indicating high levels of shear in the gulf... you don't know for sure that the shear is going to be favorable in the gulf yet.

If you were to read the blog you are posting on, you would have seen that
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Why is it so difficult -- I'd say impossible but I might be missing something -- to find a map that shows the current location of the tropical disturbance AND the location of the North American/Central American frontal boundaries that will strongly influence its course? Is there such a thing, readily available?
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Quoting IKE:
SHIPS heads 94L toward Bermuda.

Probably the same trough gets it.


The turn to the NE for 94L is going to be more dramatic than that.
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Quoting CaneWarning:


Wow, two things to track.



This blog is getting very hyped up, just wait until it hits the gulf coast everyone will be crazy.
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Good morning everyone! I am sure hoping that 93L does not head my way. The oil is here already. It would only bring it into our homes. I am hoping it does no one harm at all.
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Pat,
135. LMAO. Then it's called a "dipstick"
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Quoting DocBen:
Could that 'extra' blob south of Haiti become 95L?



Only in the "Bizarro" world of "Spaceman Spiff" and the CMC.
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Quoting FLWeatherFreak91:
The upper level winds in the Gulf aren't necessarily going to be favorable.
Yes I understand that, he was saying that if shear were to be favorable that 93L could become a hurricane and I agreed by saying that if shear were to be low with the hot SSTs there wouldn't be much stopping 93L. Sorry to make the statement so unclear.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
For being a 1008 mb low, 94L has got a bit of an ummph to it at this time. It is actually pushing into the 1016 outer edge of the Bermuda High a bit.



Animation

Its present NW direction cannot be maintained if it is to strengthen. Already, you can see 94L begin to respond to the 1016 high pressure and jog back to the SW.

94L has only two options. It takes a track across Hisp/Cuba and then into the Straights/Gulf, or it curves to the NE and becomes a fish.
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Quoting Stormchaser2007:
12z NAM simulated radar reflectivity:



Hey, I'm getting rain that day!
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we have 94L

BEGIN
NHC_ATCF
invest_al942010.invest
FSTDA
R
U
040
010
0000
201006251452
NONE
NOTIFY=ATRP
END
INVEST, AL, L, , , , , 94, 2010, DB, O, 2010062512, 9999999999, , , , , , METWATCH, , AL942010
AL, 94, 2010062418, , BEST, 0, 152N, 549W, 25, 1012, DB, 0, , 0, 0, 0, 0,
AL, 94, 2010062500, , BEST, 0, 161N, 560W, 25, 1012, DB, 0, , 0, 0, 0, 0,
AL, 94, 2010062506, , BEST, 0, 169N, 570W, 25, 1012, DB, 0, , 0, 0, 0, 0,
AL, 94, 2010062512, , BEST, 0, 178N, 578W, 25, 1013, DB, 34, NEQ, 0, 0, 0, 0, 1014, 120, 45, 0, 0, L, 0, , 0, 0, INVEST, S,

with 93L the HH have lift off THIS IS WHERE THE FUN BEGINS
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150. IKE
SHIPS heads 94L toward Bermuda.

Probably the same trough gets it.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
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12z NAM simulated radar reflectivity:

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Thank you Dr Master!

Hello everyone,....still watching and lurking a little.

I just hope if this thing developes, and it gets into the GOM, it just keeps away from the darn oil spill area... I know there is no way for some of the oil not to get into a storm, but we sure do not want a TS or even 'cane going over the worse of the spill that will be no good for everyone!

just keep this soon to be storm away from the central GOM!

Hi everyone, thanks for the info.. will check back later to see what recon finds out.
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Quoting Patrap:
What Happens if the HH chucks a sonde in the GOM during next week and it lands in La. sweet Crude...?

"It cant be that Low in MB,,the sonde must have Oil on it"..


Or that LA. Cane Sweeet Iced Tea from Popeye's!

"What the heck? It's saying the pressure is sweeet! What does that mean?"
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Quoting extreme236:
The 12z SHIPS for 94L brings shear down to favorable levels in 24 hours. But appears to increase it again by the 120 hour mark. Link


Way too soon in my opinion. Don't see the TUTT moving out that quickly.
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SSTs for 94L also become unfavorable around the 96 hour mark on the BAMM track.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting MiamiHurricanes09:
Agreed. With the scorching hot SSTs and favorable upper level winds there isn't much stopping 93L except itself.
The upper level winds in the Gulf aren't necessarily going to be favorable.
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The 12z SHIPS for 94L brings shear down to favorable levels in 24 hours. But appears to increase it again by the 120 hour mark. Link
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting Stormchaser2007:
Once recon finds those west winds, look for a renumber.
Agreed.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting extreme236:
93L IMO has the potential to be a serious Gulf Coast threat as long as the shear remains low. I could easily see a hurricane in the Gulf.
Agreed. With the scorching hot SSTs and favorable upper level winds there won't be much stopping 93L except itself.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting jpsb:
Question, your home gets destroyed by a hurricane (Ike) and you collect flood insurance, basically the insurance company 'bought' your house. Then a few years later another cane hits your house will the insurance company "buy" your house again, or will it say "hey wait a minute: we paid off once we are not going to pay off twice. thx in advance.


Theoretically, yes they will pay. They didn't "buy" your house previously, they paid to fix it. So yes, they will pay to fix it again as long as your premiums were kept current. And then they will decline to renew your policy because you file too many claims.
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What Happens if the HH chucks a sonde in the GOM during next week and it lands in La. sweet Crude...?

"It cant be that Low in MB,,the sonde must have Oil on it"..
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Once recon finds those west winds, look for a renumber.
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132. IKE
Buoy 42057.....@16.8N and 81.5W

Wind Direction (WDIR): SE ( 140 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 23.3 kts
5-day plot - Wind Gust Wind Gust (GST): 29.1 kts

5-day plot - Wave Height Wave Height (WVHT): 5.9 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 7 sec
5-day plot - Average Period Average Period (APD): 4.5 sec
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.78 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): 0.05 in ( Rising )
5-day plot - Air Temperature Air Temperature (ATMP): 79.3 F
5-day plot - Water Temperature Water Temperature (WTMP): 84.2 F
5-day plot - Dew Point Dew Point (DEWP): 77.2 F
5-day plot - Heat Index Heat Index (HEAT): 84.2 F
5-day plot - Wind Speed, Wind Gust and Atmospheric Pressure Combined plot of Wind Speed, Gust, and Air Pressure
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting iluvjess:


You trying to jinx us?


Reverse psychology
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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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