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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the blog has over 3,000 posts and it's only mid friday!
a record will be broken here soon if we dont get a new
blog later this evening. LOL!
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3078. Patrap
TD-1 NASA MSFC Viewer
Member Since: July 3, 2005 Posts: 423 Comments: 128240
will the good new is that the oil will be gone from the gulf
Member Since: May 21, 2006 Posts: 5091 Comments: 115074
Quoting Tazmanian:



wind shear is vary high in the gulf its RIP


back and forth, back and forth...
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Quoting Grecojdw:
I'm normally the Floridacasters. But today, I'm with the Texas and Mexico casters STAY AWAY FROM THE NORTHERN GULF!! Into the Bay of Campeche this must go where it should die out.
No thanks. You can have it. Really. You go first...lol
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2967 JLPR2 "Celia seems to be shrinking away"

Curses, foiled again... If it could have held itself together as a Cat.5 for another 25hundred miles, we coulda given the Hawaiians a good scare.
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Quoting JLPR2:
I just noticed something strange

Rain that was on its way to the SE coast of PR suddenly turned around and started to move towards the sea, is this caused by 94L's circulation?


No. Thunderstorms at low levels are moving west. Upper level winds are blowing the tops of the storms east (shear). When the base of the storm broke up and stopped raining, the top kept dropping rain, and was blown east.
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3070. Gorty
My thing is not quoting.

@taz

Why want it a Cat 3?
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3067. Michfan
Remember this thing doesn't have to go right over the oil spill to cause havoc. If this goes west of it then winds will be out of the south at a pretty good rate and will result in the beaches being soiled even more than they are now.
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They are all here tonight;

Wishcasters
Downcasters
Westcasters
Eastcasters
Centralcasters
Bastardicasters
Oilcasters
Tarcasters
Mexicocasters
Texascasters
Louisianacasters
Mississippicasters
Alabamacasters
Floridacasters

The only two I have not seen are the fishcaster and the JFVcaster
Cat9casters


Dont want this darn thing in the Gulf, so I would be your fishcaster. And oh yeah...*sings* "I love this blog... its my kind of place... there is something about it that just puts a big smile on my face. No user charge, yes its all free... mhmmhmmhmm, I love this blog." -Similar to "I Love This Bar" by Toby Keith

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3064. centex
Quoting wuest:
im going on a vacation to the Yucatan Peninsula in two days the weather wil be ok right? People told me it will be ok are they right?
It's going to be a timing thing. I assume Cancun or Cozumel. Early in two days could be a problem.
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am hoping TD 1 makes it too cat 3
Member Since: May 21, 2006 Posts: 5091 Comments: 115074
3062. Gorty
@Taz

The shear in the GOM as per the GFS current run is a scary weak strength.
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Quoting HurricaneSwirl:


I'm confused. I was responding to the posters who were saying Joe B. was dead wrong in his prediction that it would be a TX/LA/Mexico storm and that it would make a hard right and go over the oil. I was defending Joe B. (and the NHC for that matter because their tracks are so similar) in that it will probably go too far west to spread all the oil around too much. It wasn't a matter IF it was going into the GOM, it was a matter of WHAT PART of the GOM.

Oh, just pointing out the broadness of the uncertainty. And how it would be difficult to be wrong...
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I'm normally the Floridacasters. But today, I'm with the Texas and Mexico casters STAY AWAY FROM THE NORTHERN GULF!! Into the Bay of Campeche this must go where it should die out.
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...FIRST TROPICAL DEPRESSION OF THE ATLANTIC SEASON FORMS IN THE
WESTERN CARIBBEAN...

Images made by cyclonkid
6pm EDT Graphics Update



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3057. Michfan
Quoting wuest:


Im going on a vacation to the Yucatan Peninsula in two days the weather wil be ok right? People told me it will be ok are they right?



http://www.nhc.noaa.gov/graphics_at1.shtml?5-daynl#contents
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3056. xcool
Tazmanian LOL
Member Since: September 26, 2009 Posts: 2 Comments: 15670
3055. JLPR2
I just noticed something strange

Rain that was on its way to the SE coast of PR suddenly turned around and started to move towards the sea, is this caused by 94L's circulation?

Member Since: Posts: Comments:
Quoting KoritheMan:


GFS lifts out the shear, Taz.


oh then its not RIP
Member Since: May 21, 2006 Posts: 5091 Comments: 115074
Quoting Tazmanian:



wind shear is vary high in the gulf its RIP


GFS lifts out the shear, Taz.
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3050. Levi32
Gotta go, back later.
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3049. Michfan
Quoting wuest:
im going on a vacation to the Yucatan Peninsula in two days the weather wil be ok right? People told me it will be ok are they right?


Read the tropical storm warnings before asking questions.
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Quoting StSimonsIslandGAGuy:


Georgiacaster reporting in for duty sir! Just kidding, of course ;)


lol
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting AstroHurricane001:


If that happens, and the storm quickly restrengthens after entering the Gulf, it could be a scenario similar to Ike in terms of size, landfall location and intensity.



wind shear is vary high in the gulf its RIP
Member Since: May 21, 2006 Posts: 5091 Comments: 115074
3046. Walshy
Quoting twooks:
Can someone explain the importance to me of a big hot-tower?



IR
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Quoting Stormchaser2007:
Going out on a limb, but I think TD1 could ramp up to about 65 mph before its landfall tomorrow.



If that happens, and the storm quickly restrengthens after entering the Gulf, it could be a scenario similar to Ike in terms of size, landfall location and intensity.
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looking at afd's per trof st charles,la afd-TUESDAY...THE GLOBAL MODELS SHOW A RARE LATE JUNE FRONTAL
BOUNDARY SAGGING TOWARD THE AREA. HOW FAR THIS FRONT PROGRESSES IS
UNCERTAIN...WITH THE ECMWF HOLDING IT NORTH OF THE AREA...WHILE
THE GFS CONTINUES TO BRING IT INTO THE GULF WATERS. LEANED MORE
TWD THE ECMWF...so there's just as much uncertainty concerning the trof/front as alex.
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3042. twooks
Can someone explain the importance to me of a big hot-tower?
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Quoting atmoaggie:

NHC could be wrong, how? Forecast that a system a few miles from the gulf will be in the gulf vicinity?


I'm confused. I was responding to the posters who were saying Joe B. was dead wrong in his prediction that it would be a TX/LA/Mexico storm and that it would make a hard right and go over the oil. I was defending Joe B. (and the NHC for that matter because their tracks are so similar) in that it will probably go too far west to spread all the oil around too much. It wasn't a matter IF it was going into the GOM, it was a matter of WHAT PART of the GOM.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting atmoaggie:

If that prediction happened, I'm afraid all the water wouldn't stay under the bridge...


ROFL, what bridge. It would be gone also
Member Since: October 1, 2007 Posts: 81 Comments: 26511
3038. xcool


Member Since: September 26, 2009 Posts: 2 Comments: 15670


Looks organized and dangerous TD01. Uhmm IR is too strong so heavy rain.
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Quoting centex:
Hope we don't see that Tuesday prediction. A lot of water has gone under the bridge.

If that prediction happened, I'm afraid all the water wouldn't stay under the bridge...
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3035. Levi32
Quoting Drakoen:


All that diabatic heat in the Caribbean finally being put to use


Indeed....finally. There's a scary amount of it ready to be used.
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Quoting tropicaltank:
Does anybody have the Wilma Track?
Just google "wilma hurricane track" But why?
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3032. twooks
Quoting stormpetrol:

I'll say its Alex they just haven't registered "him" yet thats all. :)



I say it is too, but you know the NHC :P.
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Quoting TropicalNonsense:



funny all these track predictions! The last 12Z run of
the GFDL had 93L actually in SOUTH CAROLINA in 5 days.

FSU MODEL LINK Link

really, not much stock can be put into the models right now.

frankly 93l may never become anything more than a weak TS.

THERE CERTAINLY IS NO EVIDENCE TO SUPPORT ANYTHING OTHER THAN 93L BECOMING A TS RIGHT NOW IN ALL FAIRNESS.
Actually, you have nothing to support that TD #1 will stay weak, and by the way it is a tropical depression now not an invest.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting TropicalNonsense:



funny all these track predictions! The last 12Z run of
the GFDL had 93L actually in SOUTH CAROLINA in 5 days.

FSU MODEL LINK Link

really, not much stock can be put into the models right now.

frankly 93l may never become anything more than a weak TS.

THERE CERTAINLY IS NO EVIDENCE TO SUPPORT ANYTHING OTHER THAN 93L BECOMING A VERY WEAK TS RIGHT NOW IN ALL FAIRNESS.
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3029. centex
Quoting atmoaggie:

Heck, yes.

For example, without the Yucatan, the consolidation of all of this energy would be possible or likely. As it stands, I'll take a broad TS that runs out real estate before it could thoroughly consolidate and become a bigger problem for someone.

Exhibit A, what WRF was seeing this morning:


That's a huge example of a TS in the gulf.
(Or stronger...still glad it will not be able to complete the task up to potential.)
Hope we don't see that Tuesday prediction. A lot of water has gone under the bridge.
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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.