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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Thanks Storm, Gator, record. Hi Tex. :)
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1078. Patrap
www.wwl.com




The Spud Show who will interview Jeff
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1077. JamesSA
Quoting atmoaggie:

But what zip code do you think 94L will end up in?
LOL! And... how many people will die, and what are their names? We must warn them!
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We are at square one with this system if it has become a TD. The SW side of it is already interacting with land somewhat. Yet, it seems to be quickly organizing and seems to be about to start a spin that Jeff Masters mentioned as being glaringly absent. If it can spin up and gain intensity quickly (in spite of interacting with land) then you should see this system stop its westward motion and move more to the north which will in turn keep it over open water for a longer period before it crosses the narrow end of the YucPen later this weekend.

Otherwise, it remains weak, moves west, crosses over central YucPen and becomes a Tex/Mex event.
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Quoting Drakoen:


The system is 48 hours from the Yuctan Peninsula and it has acquired a well defined circulation with evident upper level outflow. I give it a 30% chance of becomming a hurricane.


We've been having rain off and on all day here in the Yucatan. BUT, we have a record 18 nests (turtles) so I'm going with the turtles and will prognosticate no hurricanes not only from 93L hitting the Yucatan, but at all this season within 300km of us (about 20° 31' 0N x 87° 10' 60W).

I'm thinking Kman should be getting wet today also.
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I don't believe that I have ever seen 2 recon planes flying into an invest. One left MS and the other left Tampa. How often do they do this ?
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Member Since: June 9, 2007 Posts: 4 Comments: 15950
1069. cg2916
Does anyone have a non-Google Earth version oir screenshots, I'm on my slow computer.
Member Since: December 21, 2007 Posts: 13 Comments: 3046
Quoting CybrTeddy:
Beginning to see winds shift to the ESE. Should see some SSW winds next.


if theres a low, we should see winds from E, the NE, then N, NW, WNW, etc. etc.
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Quoting LaCoast:
I can't say who I heard this from but from what I just heard Gov Officials from La, Miss, and Fla will have an emergency meeting this weekend somewhere and there will be high level US govt Officials involved. They are getting VERY VERY Nervous right now.

For those that haven't seen, 93L is now front page news on CNN.com and MSNBC.com.

It's unclear if the weather will cooperate with the drilling and cleanup efforts. There is a 70 percent chance that a weather system in the western Caribbean will better organize and form at least a tropical depression in the next 48 hours, the National Hurricane Center said Friday morning.

The tropical disturbance's rains have become more concentrated, surface air pressure is dropping and upper-level winds are becoming more conducive to storm development, said the hurricane center. An Air Force "hurricane hunter" plane is scheduled to head into the system Friday afternoon to determine if it has evolved into a tropical cyclone, with closed circulation around a center of low pressure.

Some forecasting models show that by early next week the system could head into the Gulf of Mexico. Allen said on CNN's "American Morning" he'll have to redeploy people and equipment to safer areas 120 hours (five days) in advance of gale-force winds (at least 32 mph).
Member Since: July 30, 2007 Posts: 76 Comments: 4063
1063. KEEPEROFTHEGATE (Mod)
Quoting atmoaggie:

But what zip code do you think 94L will end up in?


right centre field

93l fuse is lit time is near
Member Since: July 15, 2006 Posts: 178 Comments: 56141
1062. leo305
Quoting StonedCrab:


Link Google Earth


it doesn't let me open it
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Quoting StormW:


I hear ya...I REALLY miss John Hope...he was da bomb!


Indeed, and 93L underscores that yet again LOL
Member Since: August 19, 2006 Posts: 0 Comments: 15948
I think the highest winds will be found east of the center... and also north east of the center
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tropicalatlantic.com ~ via google earth
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Quoting StSimonsIslandGAGuy:
If Dr. Masters doesn't write a new entry, I think over as well, CaneWarning.


Are you going to stay up just to find out? LOL
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Quoting leo305:
anyone have a live track of the Hurricane Hunters? If so please post it here


Link Google Earth
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Quoting StormW:
It does no good right now to speculate on future forecast track, until it enters the GOMEX...until we see WHERE it enters, and WHAT STRENGTH it becomes. Remember too, I've seen the steering pattern change in less than 72 hours.

But what zip code do you think 94L will end up in?
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Quoting jazzygal:
Dr. Masters will be on WWL Radio between 1 and 4 today.


Thanks for the FYI. I'll tune in now.
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Quoting LaCoast:
I can't say who I heard this from but from what I just heard Gov Officials from La, Miss, and Fla will have an emergency meeting this weekend somewhere and there will be high level US govt Officials involved. They are getting VERY VERY Nervous right now.


The era of big government is over. Welcome to the era of unfreaking-believably and monstrously enormous government. It was a nice Republic, while it lasted.
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Quoting Orcasystems:


I don't even go to it.. I know within seconds of anything changing on it... 15 people will cut and paste it here :)


When did you figure that out?
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Quoting wunderkidcayman:
yes kmanislander in HD as well the HH are out nearing the COC now so what you this a possible TS watch for us if this is TD1 or TS ALEX


Not coming anywhere near the Cayman Islands. No watches needed
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Beginning to see winds shift to the ESE. Should see some SSW winds next.
Member Since: July 8, 2005 Posts: 259 Comments: 24579
Wow, there are some yellows showing up on 93L now. It's getting it's act together.
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1045. LaCoast
Quoting jazzygal:
Dr. Masters will be on WWL Radio between 1 and 4 today.

Like for all 3 hours or sometime between that time frame?
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Recon is finding 30 mph winds now... I think we will see a TS here since I think that by 5 PM they will find a good chunk of TS force winds.... especially NE of the center
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Quoting leo305:


link to the hurricane hunters track?


Link
Member Since: June 9, 2007 Posts: 4 Comments: 15950
Tonight's going to be fun...
Member Since: June 9, 2007 Posts: 4 Comments: 15950
1040. leo305
Quoting Stormchaser2007:
Down to 1006.4


link to the hurricane hunters track?
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Quoting gator23:

XTRP stands fo Extrapolation and its not really a model, just an extrapolation of all models.

??? No, XTRP is simply a track of maintaining the system's current speed and direction. No other dynamics or modeling included.
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1038. cg2916
Quoting MiamiHurricanes09:
1000+ comments posted in 3 and a half hours over an invest.


4-5 posts pedr minute!
Member Since: December 21, 2007 Posts: 13 Comments: 3046
Quoting LaCoast:
I can't say who I heard this from but from what I just heard Gov Officials from La, Miss, and Fla will have an emergency meeting this weekend somewhere and there will be high level US govt Officials involved. They are getting VERY VERY Nervous right now.


Uh huh.
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Quoting Orcasystems:


Link


The clouds still block the barbs in that link.. ?
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yes kmanislander in HD as well the HH are out nearing the COC now so what you this a possible TS watch for us if this is TD1 or TS ALEX
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Down to 1006.4
Member Since: June 9, 2007 Posts: 4 Comments: 15950
Dr. Masters will be on WWL Radio between 1 and 4 today.
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1030. LaCoast
I can't say who I heard this from but from what I just heard Gov Officials from La, Miss, and Fla will have an emergency meeting this weekend somewhere and there will be high level US govt Officials involved. They are getting VERY VERY Nervous right now.
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Quoting StSimonsIslandGAGuy:


4,000 comments by midnight CaneWarning? Call over or under :)

When I got on here ten minutes ago there where only about 800 comments, now theres over 1000!
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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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