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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Quoting MiamiHurricanes09:
So they're think we are going to see Alex. Looks to stay TD status over land.


Also looks like it is moving just slightly north of west if i am reading it right
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"I guess everyone who's out of work because of the offshore drilling stoppage deserve that too?"

Actually, all those poor offshore oil workers were being "put out of work" by a moratorium that prevented the drilling of 36 DRILLING wells, vs. the literally thousands of PRODUCTION wells currently in operation in the Gulf Coastal area. They were doing all that whining over 36 wells. Oil PRODUCTION was not shut down, only DRILLING. Big difference. Those guys still had plenty of work.
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AOI
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Quoting sailingallover:

Friday and they want to skip out early..


I think they may be in for a LONG weekend
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Quoting weathermanwannabe:


Actually looks pretty stationary to me right now and the steering currents are almost weak/non-existant around it at the moment per the latest CIMSS charts if I am reading them correctly....But I can't commit to a due North movement at this time...... :)


Using my own eyes, I'd say it has been stationary since yesterday, but you don't want to make your life and death decisions on the basis of what people on here say. :)
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623. xcool
42057
27.4 kts SSE
Member Since: September 26, 2009 Posts: 2 Comments: 15670
Quoting Levi32:
Good morning all.

Tropical Tidbit for Friday, June 25th, with Video


Very nice presentation Levi... Thanks!
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Quoting RCThunder:


Why would they do that? Weird to read a 2pm update at 12:45...


They might be turning their attention towards a possible special tropical disturbance statement....
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I actually meant recent models (my bad for the ambiguous wording)...I'm well aware that a week out, everyone (especially here) wants to make every low that rolls off the coast of Africa a Cat 5. LOL
Quoting sailingallover:

Modles have done everything with 93L from nothing to a cat 2hurricane hitting the Gulf coast right at New Orleans.
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RIGHT over the COC

Member Since: June 9, 2007 Posts: 4 Comments: 15889
Quoting MiamiHurricanes09:
Sucks they are probably going to have to be posting advisories on the weekend.


No they write them in advance and have them posted automatically for the whole weekend.
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If you have Google Earth, you can watch the recon data with this KMZ:

http://www.tropicalatlantic.com/recon/ge/Atlantic.kmz



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Quoting sailingallover:

Friday and they want to skip out early..
Sucks they are probably going to have to be posting advisories on the weekend.
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Quoting trey33:


But I would suggest you not tell anyone you are Captain Underpants or TPD may arrest you....


Huh?
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Quoting MiamiHurricanes09:
NHC released the TWD an hour early.

Friday and they want to skip out early..
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Having a prob with it....
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Quoting RCThunder:


Why would they do that? Weird to read a 2pm update at 12:45...


Especially strange since they could include some initial recon data if it were released at 2pm.
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Quoting nrtiwlnvragn:
NHC on 93L


AL 93 2010062512 03 OFCL 0 165N 825W 30
AL 93 2010062512 03 OFCL 3 167N 829W 30
AL 93 2010062512 03 OFCL 12 173N 840W 30
AL 93 2010062512 03 OFCL 24 183N 860W 40
AL 93 2010062512 03 OFCL 36 190N 875W 45
AL 93 2010062512 03 OFCL 48 200N 890W 25
AL 93 2010062512 03 OFCL 72 220N 910W 25
AL 93 2010062512 03 OFCL 96 240N 930W 35
AL 93 2010062512 03 OFCL 120 245N 950W 45
So they're think we are going to see Alex. Looks to stay TD status over land.
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Quoting CaneWarning:


Come to Tampa, I will entertain you.


But I would suggest you not tell anyone you are Captain Underpants or TPD may arrest you....
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Quoting MiamiHurricanes09:
NHC released the TWD an hour early.


Why would they do that? Weird to read a 2pm update at 12:45...
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NHC on 93L


AL 93 2010062512 03 OFCL 0 165N 825W 30
AL 93 2010062512 03 OFCL 3 167N 829W 30
AL 93 2010062512 03 OFCL 12 173N 840W 30
AL 93 2010062512 03 OFCL 24 183N 860W 40
AL 93 2010062512 03 OFCL 36 190N 875W 45
AL 93 2010062512 03 OFCL 48 200N 890W 25
AL 93 2010062512 03 OFCL 72 220N 910W 25
AL 93 2010062512 03 OFCL 96 240N 930W 35
AL 93 2010062512 03 OFCL 120 245N 950W 45
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607. IKE
Quoting scottsvb:
Peeps just look near 17N and 83.1W this is where you want a Blow up and Sustained area of intense T-Storms. Everything else is away from the LLC.


I see a blowup right there on the 1615UTC IR.
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Time: 16:45:00Z
Coordinates: 21.1833N 85.85W
Acft. Static Air Press: 376.1 mb (~ 11.11 inHg)
Acft. Geopotential Hgt: 8,084 meters (~ 26,522 feet)
Extrap. Sfc. Press: -
D-value: 466 meters (~ 1,529 feet)
Flt. Lvl. Wind (30s): From 287° at 5 knots (From the WNW at ~ 5.8 mph)
Air Temp: -16.5°C (~ 2.3°F)
Dew Pt: -22.7°C (~ -8.9°F)
Peak (10s) Flt. Lvl. Wind: 6 knots (~ 6.9 mph)
SFMR Peak (10s) Sfc. Wind: -
SFMR Rain Rate: -
(*) Denotes suspect data

Recon, Via Google Earth.
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That's a nice graphic, GetReal.
(here's the link for othersCIMSSLink )Looks like the Hunters are on perfect schedule.
Gives me faith in at least this branch of government. Go science!
Member Since: July 11, 2006 Posts: 14 Comments: 11322
Quoting jpsb:
Do you have oil on your beaches? If so that oil did not come from a La rig, or a Tx rig or a Ms rig. It came from a federally licensed and regulated rig. I don't know why this is so hard to understand. La, Tx, Ms and Al had NOTHING to do with this spill.
I just hope 93L does not push oil on to your beanches or anyone else's. I am routing for a Mexico or Texas hit (even thou I live in Texas) because I do not want a oil-tar cane. That would be horrible.
The rig is licensed and regulated by the feds because offshore drilling is not illegal and that is who you go through to get the license. They issue it when a properly documented plan is approved... this is not the same thing as forcing it upon states that don't want it! Offshore drilling is legal nationally and left up to the states about whether it is legal on their specific waters. States elsewhere have passed laws prohibiting this on their waters, like New Jersey (yeah, I know, irony alert) for example. I don't see the feds mowing down those state legislatures on behalf of big oil. The determination of some people to hate the federal government is just stunning to me. The political representatives of individual states wanted oil companies to come here and drill, rolled out the welcome mat, promised jobs and big money from it. But it is absolutely false to say that the states had "nothing" to do with it. They invited them when they had the option of saying "Keep Out," like Florida, and there would have been not one thing that your big bad federal government could've done about it if they'd said that. I'm done with this.
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Recon still way up in the atmosphere.

16:45:00Z 21.183N 85.850W 376.1 mb
(~ 11.11 inHg) 8,084 meters
(~ 26,522 feet)
- 466 meters
(~ 1,529 feet) From 287° at 5 knots
(From the WNW at ~ 5.8 mph) -16.5°C
(~ 2.3°F) -22.7°C
(~ -8.9°F) 6 knots
(~ 6.9 mph)
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Quoting EarthMuffin:
Have any of the models actually predicted 93L becoming a hurricane? Last models I checked show it becoming a weak TS at best, and GOMEX landfall predictions look like a game of pin the tail on the donkey...

I find 94L much more interesting (and thankfully much less of a threat to the GOMEX).

Modles have done everything with 93L from nothing to a cat 2hurricane hitting the Gulf coast right at New Orleans.
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If Something pretty funny,but 93L seems to be bigger than Darby-or at least the same size.
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i see the riper made 93L even more mader
Member Since: May 21, 2006 Posts: 5091 Comments: 115081
Alright Good night AussieStorm we prob. might have TD1 by time you go into deep sleep 1 hour and 30 minute or so
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I'm very impressed with 93L on shortwave IR. Loop.

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NHC released the TWD an hour early.
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Quoting Chicklit:
Good afternoon. Any move north will be good for 93L.
then move any other direction that is bad for 93l
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Recon just split the gap and is officially in the Caribbean sea
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ARES 4.4 payload
19.874 N 85.059 W (19°52'27" N 85°3'33" W)

Site elevation: sea level
Air temp height: 10 m above site elevation
Anemometer height: 10 m above site elevation
Barometer elevation: sea level
Sea temp depth: 1 m below site elevation
Water depth: 4446 m
Watch circle radius: 5083 yards

Wind Direction (WDIR): NE ( 50 deg true )
Wind Speed (WSPD): 15.5 kts
Wind Gust (GST): 19.4 kts
Wave Height (WVHT): 5.9 ft
Dominant Wave Period (DPD): 7 sec
Average Period (APD): 5.5 sec
Mean Wave Direction (MWD): ESE ( 102 deg true )
Atmospheric Pressure (PRES): 29.86 in
Pressure Tendency (PTDY): +0.02 in ( Rising )
Air Temperature (ATMP): 85.5 °F
Water Temperature (WTMP): 85.8 °F
Dew Point (DEWP): 78.3 °F
Heat Index (HEAT): 97.7 °F

interesting...
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Quoting SavannahStorm:


UCF


HA!
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AXNT20 KNHC 251633
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI JUN 25 2010

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1615 UTC...

...SPECIAL FEATURE...

A WEST CENTRAL CARIBBEAN SEA TROPICAL WAVE IS ALONG 82W...
DRIFTING WESTWARD. A 1006 MB LOW PRESSURE CENTER IS ALONG THE
WAVE NEAR 17N. STRONG SHOWERS AND THUNDERSTORMS ARE FROM 13N
TO 17N BETWEEN 81W AND 83W/84W...AT LEAST REACHING THE EASTERN
COASTS OF HONDURAS AND NICARAGUA. OTHER STRONG SHOWERS AND
THUNDERSTORMS ARE OVER THE WATERS IN THE NORTHWESTERN CORNER...
TO THE SOUTH OF 19N BETWEEN 85W AND THE YUCATAN PENINSULA AND
BELIZE. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS ARE TO THE NORTH OF 19N BETWEEN 79W AND THE
NORTHEASTERN THE NORTHEASTERN YUCATAN PENINSULA. THE SURFACE
LOW PRESSURE CENTER IS SHOWING SIGNS OF ORGANIZATION. THE
SURFACE PRESSURES ARE FALLING. UPPER-LEVEL WINDS GRADUALLY
ARE BECOMING MORE CONDUCIVE FOR DEVELOPMENT. IT IS LIKELY
THAT THIS SYSTEM MAY BECOME A TROPICAL DEPRESSION BEFORE IT
REACHES THE YUCATAN PENINSULA DURING THE NEXT FEW DAYS.
THE CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS IS HIGH. AN AIR FORCE RECONNAISSANCE PLANE
IS SCHEDULED TO INVESTIGATE THIS AREA OF WEATHER LATER TODAY.

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It's not a wrap yet, but the blobs are starting to organize around the upper anti-cycl.
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Peeps just look near 17N and 83.1W this is where you want a Blow up and Sustained area of intense T-Storms. Everything else is away from the LLC.
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Look what 93L is doing to oil prices just today (from CNBC):

"Oil soared more than 3 percent Friday on concerns that a storm in the Caribbean may move towards the Gulf of Mexico, where oil facilities are clustered and BP continues to fight an oil spill. "
Member Since: August 2, 2007 Posts: 19 Comments: 19234
yup anticyclone is not over the center again, but it does not appear to be affecting 93L all that much now
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Recon almost there...hasnt dropped to 700mb yet.
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Quoting AussieStorm:

That's what i'm doing....

Nice and cool here... 61.5°F to be exact.


That's cheating, it's your winter and of course we're just starting our above average summer of 2010!
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580. jpsb
Quoting LPStormspotter:


I agree. Im in TX and would rather a landfall here or Mexico to spare the beaches in other states..
Yup, that and BP closing down recovery efforts because of the storm is what I fear most. I really really want this spill to come to an end as fast as possible. We in Texas can take one for the team or Mexico can (even better).
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Member Since: July 4, 2005 Posts: 204 Comments: 8873

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.