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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3229. centex
This late June trough which picks up a Mid Yucatan weakened system due noth is highly suspect.
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Quoting nrtiwlnvragn:


HWRF shifted from the Gulf Coast to towards Mexico.



oh
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Quoting Tazmanian:
During active periods of hurricane season, these rules will be strictly enforced. Violations will be met with a minimum 24 hour ban.


the pot calling the kettle black with you saying that...lol...especially lately...
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Quoting Tazmanian:
Quoting nrtiwlnvragn:
Big change in HWRF


what dos that mean


HWRF shifted from the Gulf Coast to towards Mexico.
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3224. HadesGodWyvern (Mod)
hurricane556 11:22 PM GMT on June 25, 2010
When does recon go back in?


around 2am EDT, hurricane 556
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Blog Update!

June 25, 2010 - 7:30 PM EDT - First Tropical Depression Develops -
Member Since: September 2, 2009 Posts: 130 Comments: 21162
3220. Hhunter
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Quoting IKE:
HWRF finally gave in. Good.


Hopefully the Yucatan disrupts the TD further and weakens it.
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Quoting StormW:


Are you serious?

Into the BOC/GOMEX
lol!
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The HPC shows more than 5 inches of rain approaching Tamaulipas between next tuesday-thursday. AND also something going toward Florida... hum...

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3216. Michfan
Recon left a while ago.
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We all knew it would be bad once it got here.
The questions now are, can it go over Yucatan Peninsula and weaken?
Will the trough lift it or will it stay in the western part of the GOM and landfall there?
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Quoting btwntx08:

has it close to me



oh cool
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When is the next HH recon scheduled for TD!?
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does anyone know if the air recon is still out there checking TD1
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3207. IKE
Quoting nrtiwlnvragn:



GFDL didn't


HOUR:108.0 LONG: -91.95 LAT: 27.85 MIN PRESS (hPa): 978.82 MAX SURF WIND (KNOTS): 72.75
HOUR:114.0 LONG: -92.03 LAT: 28.70 MIN PRESS (hPa): 968.67 MAX SURF WIND (KNOTS): 85.37
HOUR:120.0 LONG: -91.94 LAT: 29.30 MIN PRESS (hPa): 966.58 MAX SURF WIND (KNOTS): 83.31
HOUR:126.0 LONG: -91.37 LAT: 29.95 MIN PRESS (hPa): 970.80 MAX SURF WIND (KNOTS): 68.99


:(
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting amd:


I would not be at all shocked if they wait until the next recon arrives at TD1 around 1 or 2 a.m. IMHO.





I think TD1 is extremely close..if not a Tropical Storm...8PM it will be upgraded in my opinion. I'm going to go analyze and update my site. Be back in a few.
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3205. Gorty
@amd

Yeah, I wouldnt be shcoked either, lol.
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Quoting IKE:
HWRF finally gave in. Good.



GFDL didn't


HOUR:108.0 LONG: -91.95 LAT: 27.85 MIN PRESS (hPa): 978.82 MAX SURF WIND (KNOTS): 72.75
HOUR:114.0 LONG: -92.03 LAT: 28.70 MIN PRESS (hPa): 968.67 MAX SURF WIND (KNOTS): 85.37
HOUR:120.0 LONG: -91.94 LAT: 29.30 MIN PRESS (hPa): 966.58 MAX SURF WIND (KNOTS): 83.31
HOUR:126.0 LONG: -91.37 LAT: 29.95 MIN PRESS (hPa): 970.80 MAX SURF WIND (KNOTS): 68.99
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3203. Drakoen
Quoting IKE:
HWRF finally gave in. Good.


Yea definitely don't need anything going over the oil
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Quoting muddertracker:
Egocaster...my personal fav


I like the Contrarycaster. They have no choice but to go against the opinion of 90% of the board.
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ADT TD01

2010JUN25 224500 2.0 1009.0/ +0.0 / 30.0 2.0 2.1 2.8 0.1T/hour OFF OFF -75.86 -65.54 UNIFRM N/A 16.59 83.61 FCST

0.1T/hour taht means in 3 or 4 hours will be a TS. Cloud region temperatur -75.86 Celcius
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Looks like TD1 may stay W.

If thats the case...

Lots of busted models coming.
Member Since: June 9, 2007 Posts: 4 Comments: 15884
When does recon go back in?
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How many think TS Alex at 8pm?
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ok, I'm confussed. The NOAA has a track of most likely somewhere in TX and our locals (channel 6) was just saying that the high should stick and it should make landfall somewhere in Mexico. Did I miss something??
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Quoting extreme236:


I'd assume their using the new GFS


6PM 18Z GFS ENSEMBLE ....

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Quoting CybrTeddy:
nrt could you tell me where you get the site that gave us the 'renumber' for 93L to TD1?



ATCF
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Quoting Michfan:


Its probably JFV again.


I dunno. Don't think so, he's annoying but not in the same way as JFV. lol

Anyway, moving on back to 01L or soon-to-be Alex.
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3190. amd
Quoting Gorty:
Should be interestinh at 8 to see if they will do anything with TD 1. if not, we have to wait till 11.


I would not be at all shocked if they wait until the next recon arrives at TD1 around 1 or 2 a.m. IMHO.



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3189. IKE
HWRF finally gave in. Good.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting btwntx08:

OMG



omg what what is it showing
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Quoting PanhandleChuck:
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

fatladycaster reporting for duty. songs loaded and locked. um... I guess I'm a bit early....
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Quoting Drakoen:


Yea. It is looking more likely this wants to go more westward than poleward

finally, some good news.
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Wow, I checked our system for the first time today. It is organizing quickly and it is huge!

Anyways, I will go back to reading the blog for learning, keep it up guys!
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3184. centex
In case anyone wondered what experts are saying.

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http://nario.com/hurricane/lighterside.htm#we_moved
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Quoting CybrTeddy:
Caffinehog, you know how long people have been saying that about 93L before it became TD 1? Lol, the COC is not going to hit Honduras.. its moving NW away from it.
I think it will. Even if it doesn't, interaction with land may well weaken this. Then it has to make it over the Yucatan with sufficient strength to recurve north. Basically, my point is that this has a LONG way to go before it becomes a real threat to the oil areas, and there is no guarantee that it will make it that far.
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nrt could you tell me where you get the site that gave us the 'renumber' for 93L to TD1?
Member Since: July 8, 2005 Posts: 259 Comments: 23923
Quoting nrtiwlnvragn:
Big change in HWRF


what dos that mean
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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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