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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2028. Patrap
Member Since: July 3, 2005 Posts: 437 Comments: 134742


AOI
Member Since: Posts: Comments:
2026. centex
NHC may jump early because of the oil fiasco.
Member Since: Posts: Comments:
2025. Levi32
Searching for the center. 20:35z:

Member Since: November 24, 2005 Posts: 635 Comments: 26775
2024. scott39
If the direction for 93L is NW and it just starting to develope, I dont understand how anybody really knows where its going more than 24 hours from now?
Member Since: June 13, 2009 Posts: 0 Comments: 6960
Quoting StormW:


Maybe T.S. strength.



How far west of Isla Blanca will this storm cross the Yucatan peninsula? Could it exit near Caracol? A crossing is a crossing, right? ;)
Member Since: Posts: Comments:
Quoting JamesSA:
LOL!
"We must evacuate North America immediately!"


And the lower portions of Canada...this is a big one
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2020. Patrap
Member Since: July 3, 2005 Posts: 437 Comments: 134742
2019. Drakoen
Quoting HaboobsRsweet:
Anyone else not getting the data to update on google earth?
I'm not
Member Since: Posts: Comments:
2018. fmbill
Quoting StormW:


Who's playin?


LOL!!! That's what I tell family members that ask me about a system that the models can't agree on.
Member Since: Posts: Comments:
Quoting unf97:
It is a pretty good probability that Cozumel and Cancun is going to get impacted heavily by this system.


I sent one of my Buds in Cancun an e-mail a lttile while ago to advise him of the possibility and to go ahead and shop tommorow for supplies in case of a rush down there on Sunday or Monday...
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2015. GWTEX
Quoting StonedCrab:


Dude, we pay the bank for Hurricane Insurance every year, and we just want to collect some of it back. Is that So Wrong???? LOL
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Quoting smmcdavid:


You amuse me... ;)


Hey, kiddo! Brace yourself, the drama squad is about to jump on you...LOL
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Quoting tennisgirl08:


I respectfully disagree. The oil spill will influence NHC forecasts this year. I believe it will make them even more conservative than usual.


Most likely no it will not. Do you have any evidence to back up this claim? Why would they be more conservative only to make themselves possibly more wrong?
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2011. Patrap
Member Since: July 3, 2005 Posts: 437 Comments: 134742
Quoting tennisgirl08:


Lots of politics involved. Especially now with the oil spill. No doubt a TD will be declared, but a Tropical Storm will cause major media coverage and could threaten relief well efforts right now in the GOMEX.



You are exactly right. Unfortunately, they will probably pull out even dor a Dpression. I'm sure the NHC has already been advised to lean to the conservative side.
Anyone else not getting the data to update on google earth?
Member Since: May 20, 2009 Posts: 0 Comments: 1640
2008. leo305
I am seeing something that may end up not allowing this system to "R.I" there may be a mid level spin to the south and east of the center, this is beginning to attract convection.. based on vis sat
Member Since: Posts: Comments:
Quoting ezcColony:
Would not you agree that the biggest thing against 93L being a tropical depression is that Jeff Masters has not posted any update to his blog?


No, I disagree totally...it's bacause no clearly defined closed surface low has been detected...as yet
Member Since: Posts: Comments:
2005. JamesSA
Quoting Floodman:
Nearly 2000 comments since 9AM, pretty much all saying variations of the same 6 things (with some notable exceptions):

It's a TD/TS/CAT1
It's NOT a TD/TSCAT1
It's going (pick a compass point)
It's going to hit (pick a city/state)
I'm the blog police and you're busted
No, I'm crazy, so I can't be busted
LOL!
"We must evacuate North America immediately!"
Member Since: Posts: Comments:
Quoting extreme236:


It has nothing to do with politics.


I respectfully disagree. The oil spill will influence NHC forecasts this year. I believe it will make them even more conservative than usual.
Member Since: Posts: Comments:
Quoting Floodman:
Nearly 2000 comments since 9AM, pretty much all saying variations of the same 6 things (with some notable exceptions):

It's a TD/TS/CAT1
It's NOT a TD/TSCAT1
It's going (pick a compass point)
It's going to hit (pick a city/state)
I'm the blog police and you're busted
No, I'm crazy, so I can't be busted


You amuse me... ;)
Member Since: Posts: Comments:
2002. Levi32
As of 18:35z....pressure down to 1005.0mb and steady as the plane heads westward, still finding southerly winds of 20 knots which means they have to keep going west until they find the center.
Member Since: November 24, 2005 Posts: 635 Comments: 26775
2000. Patrap
93L Floater - Visible Loop
Member Since: July 3, 2005 Posts: 437 Comments: 134742
Quoting homelesswanderer:


Yep it has begun. Lets hope it remains just interesting. :)


what? Did I miss something?
Member Since: July 2, 2009 Posts: 0 Comments: 2811
first mention in Houston discussion of local effects of "disturbance"

Area forecast discussion
National Weather Service Houston/Galveston Texas
330 PM CDT Friday Jun 25 2010


Discussion...
much less coverage today with only scattered short lived showers and thunderstorms mainly south of a College Station to Livingston
line but the seabreeze continues to March inland. Temperatures quickly dropping into the lower 80s in the rain cooled air. Potential for more storms across the north where greater instability still resides. Storms should again wain with the loss of heating but can't rule out an isolated storm after midnight.
Drier air continues to overspread the area Saturday so rain chances are going to be slim and with less cloud cover the issue will be heat. Heat indices this weekend during the afternoon hours could top out at 101 to 106. An upper disturbance over the eastern Gulf will move east but ecm/GFS take it west-northwest into la and stall it
as upper ridge over Texas weakens slightly. Models still diverging with the upper trough over the eastern U.S. Early next week but
the consensus looks to take to the tropical wave/disturbance in the western Caribbean west across the Yucatan and into the SW Gulf. Hurricane hunter out there sampling the system now and will have to wait to get the decision from NHC in the next hour on the official track if it has become a tropical depression. Later forecast periods have continued the trend toward the European model (ecmwf) with
increasing moisture and 20-30 probability of precipitation for the southern areas Tuesday
and beyond.


If the system develops then Upper Texas coast could have elevated tide issues Tuesday and beyond but still to early to tell with any
confidence.
Member Since: Posts: Comments:
1997. IKE
Quoting Levi32:


That it will, and for that we should be thankful.


Hope no one is hurt where it's going, but that is good news...it will weaken considerably.
Member Since: June 9, 2005 Posts: 23 Comments: 37885
1995. leo305
Quoting Tazmanian:
no need for DMIN and DMAX any more


it will feel DMAX, it will get stronger convection
Member Since: Posts: Comments:
i would not be geting your hop up yet for a MX land fall there many days too go and if 93L is moveing so slow has it get stronger it will go more N and a way from MX


all so MX dos not need other A storm any way the 1st A storm was bad
Member Since: May 21, 2006 Posts: 5096 Comments: 116603
Quoting GWTEX:
Ive been a watcher on here for a couple of years and have one question. What is wrong with you Florida people? I hope we dont get hit with gulf storms here in Texas and hope the same for others but a majority of yall are wishcasters and pray for storms.The funniest part of the whole thing is when people totally ignore models when they dont push a storm in your direction. Sorry but I had to get that off my chest.Get a life! Now, back to watch and learn mode.


Dude, we pay the bank for Hurricane Insurance every year, and we just want to collect some of it back. Is that So Wrong???? LOL
Member Since: Posts: Comments:
The system's circulation is very large now, but it likely won't stay the same size. A cyclone's size (cloud coverage) will vary based on number of factors. Mainly environmental conditions such as shear, water temperature etc. Stronger systems often have varying changes in not just cloud coverage but also wind field, due to things like eyewall replacement cycles.
Member Since: Posts: Comments:
Nearly 2000 comments since 9AM, pretty much all saying variations of the same 6 things (with some notable exceptions):

It's a TD/TS/CAT1
It's NOT a TD/TSCAT1
It's going (pick a compass point)
It's going to hit (pick a city/state)
I'm the blog police and you're busted
No, I'm crazy, so I can't be busted
Member Since: Posts: Comments:
1989. Grothar
It has never looked this good. I don't care which way the winds are blowing. This system will do what it wants, as most of them do. Don't overanalyze too much.

Member Since: Posts: Comments:
Quoting iluvjess:


I can't point to any specific evidence of the NHC playing politics with tropical weather.
Member Since: Posts: Comments:
Quoting TropicalNonsense:



I agree totally Levi32. The Anticyclone will help 93L survive better than expected
even once it makes landfall negating much of the usual downgrade/discoupling effects.

If by chance 93L can keep it's center just offshore for awhile we could be looking at a
Rapid Intensification Cycle perhaps even here shortly.

Also the models should be getting a better handle on 93L most likely in the next runs
as 93L's center becomes more pronounced which is likely to stir this blog up when the
new tracks come out.

This is gonna be an exciting next few days! I hope everyone is paying attention and ready.
Member Since: Posts: Comments:
Quoting Levi32:


Hey Levi what website are you using to get satellite images on Google Earth?
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Quoting extreme236:


It has nothing to do with politics.

Wrong answer! lol
Quoting btwntx08:

OMG lol interesting


Yep it has begun. Lets hope it remains just interesting. :)
Member Since: August 15, 2008 Posts: 10 Comments: 3665
1981. Levi32
Quoting IKE:


16.5N...93L will spend quite a bit of time over the Yucatan.


That it will, and for that we should be thankful.
Member Since: November 24, 2005 Posts: 635 Comments: 26775
1980. Patrap

Were gonna try and Birdie the Next TWO.

He's going with the GFDL seems,..wait ,no a last minute switch to da GFS !

Hmmmm...its a gamble.

Lets see how it plays.
Member Since: July 3, 2005 Posts: 437 Comments: 134742
I'm thinking 16.5 N 83.5W according to latest visible imagery.
Member Since: July 15, 2006 Posts: 17 Comments: 10298

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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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