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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3178. IKE
Quoting extreme236:


I'd assume their using the new GFS


You're correct....GFS vol. 2 does show a SW GOM system...but look where the moisture is pooling at....

at 120 hours....



Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting nrtiwlnvragn:
Big change in HWRF




Big shift.. However, I'm looking for a northward component, especially if this does the unthinkable and becomes a minimal Hurricane at landfall.
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3176. Drakoen
Quoting Stormchaser2007:


Looks like the ECMWF.


Further north than the ECMWF who plants this in the southern BOC
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During active periods of hurricane season, these rules will be strictly enforced. Violations will be met with a minimum 24 hour ban.
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
3173. Michfan
Quoting HurricaneSwirl:


And what he did with Michfan's post should have him permabanned. Much worse than mine.


Its probably JFV again.
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Quoting stormwatcherCI:
Any chance TD 1 turns NE BEFORE exiting the Caribbean ?


Nope.
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I think it's peculiar that the NHC will make the forecast a "split down the middle" of the model consensus. I think it will go east (fl panhandle), or go west (like browsville). However, I don't think it will go anywhere near the middle track of the consensus. My guess (which will probably change in 12 hours, I'm entitled to do that on occasion), will be Southern Mississippi to Pensacola.
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3170. Drakoen
Quoting Stormchaser2007:
Pretty close to CA still. If this was heading N instead of NW/WNW, this would be a pretty potent storm.



Yea. It is looking more likely this wants to go more westward than poleward
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3169. Gorty
Should be interestinh at 8 to see if they will do anything with TD 1. if not, we have to wait till 11.
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Quoting watchingnva:


i just now realized that and apologize ...sorry, i need to look back further before responding...wuest, your gone....


And what he did with Michfan's post should have him permabanned. Much worse than mine.
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Quoting nrtiwlnvragn:
Big change in HWRF




Looks like the ECMWF.
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3165. mobal
Quoting MrNatural:


The other side of what?


The yucatan...
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Guys, what would be your guess after TD1 reaches GOM? Will it make it to a hurricane or at the most TS?
The shear forecasts are not arriving to a consensus...
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It will take one blow up of storms over the center to see this rapidly intensify. It's possible, not written in stone, but possible. Very impressive this evening.
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3162. Drakoen
Quoting nrtiwlnvragn:
Big change in HWRF




That is a big shift
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3161. Michfan
Quoting MrNatural:


The other side of what?


The Yucatan.
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Pretty close to CA still. If this was heading N instead of NW/WNW, this would be a pretty potent storm.

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Quoting HurricaneSwirl:


I didn't make that original post... He quoted me and changed my original post in the quote...


i just now realized that and apologize ...sorry, i need to look back further before responding...wuest, your gone....
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GOES East loop of TD-1/Alex
Member Since: July 8, 2005 Posts: 259 Comments: 24574
Quoting StormW:


I don't think that will be too much of factor once it emerges on the other side.


The other side of what?
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Big change in HWRF


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3154. Hhunter
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Any chance TD 1 turns NE BEFORE exiting the Caribbean ?
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3152. HadesGodWyvern (Mod)
heh actually the code name is ATL012010 =P
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Quoting IKE:
"AFTER 72 HOURS THE TRACK MODEL GUIDANCE
DIVERGES...WITH ONE GROUP...INCLUDING THE HWRF AND GFDL...TAKING
THE SYSTEM ON A MORE NORTHERLY OR NORTHEASTERLY TRACK. A SECOND
GROUP OF GUIDANCE...INCLUDING THE GFS...ECMWF AND NOGAPS KEEPS THE
SYSTEM ON A MORE WESTERLY TRACK OVER THE SOUTHERN GULF OF MEXICO.
THE OFFICIAL FORECAST IS A BLEND OF THESE TWO."


???



I'd assume their using the new GFS
Member Since: August 2, 2007 Posts: 19 Comments: 19234
yoou for got Ripcaster
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
Quoting wuest:


wow ok y would you write that?


You're obviously still in middle school. Your immaturity should get you perma-banned.
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3147. Michfan


Even better shot of that CDO forming.
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3146. xcool
TropicalNonsense .HELL NO
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Quoting watchingnva:


what was the point of ur original post....huh...



That wasn't his original post. Wuest has done it to a few other bloggers (Storm and Taz) as well.

Just wuest, ignore user, and move on.
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Continuing to increase in organization..
Member Since: July 8, 2005 Posts: 259 Comments: 24574
3106 if you look at the code name 01L it looks like oil is this foreshadowing? What are the possibilities of this storm strength and landfall?
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Quoting watchingnva:


what was the point of ur original post....huh...



I didn't make that original post... He quoted me and changed my original post in the quote...
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Quoting xcool:


let me guess by your graphic....xcool you live in Texas??
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Quoting Tazmanian:
will the good new is that the oil will be gone from the gulf
Ban this Guy!
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3138. IKE
"AFTER 72 HOURS THE TRACK MODEL GUIDANCE
DIVERGES...WITH ONE GROUP...INCLUDING THE HWRF AND GFDL...TAKING
THE SYSTEM ON A MORE NORTHERLY OR NORTHEASTERLY TRACK. A SECOND
GROUP OF GUIDANCE...INCLUDING THE GFS...ECMWF AND NOGAPS KEEPS THE
SYSTEM ON A MORE WESTERLY TRACK OVER THE SOUTHERN GULF OF MEXICO.
THE OFFICIAL FORECAST IS A BLEND OF THESE TWO."


???

Member Since: June 9, 2005 Posts: 23 Comments: 37860
3137. Drakoen
I agree with the NHC track considering how spread out the models are:

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Quoting Drakoen:


Huge.
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deleted, poor taste
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3134. GetReal
If you do not like the results of the latest model runs just stick around. I am more than sure, that over the next 24 hours, we will be able to find at least one model run, somewhere, that will make everyone happy!!!
Member Since: July 4, 2005 Posts: 204 Comments: 8898
3133. centex
Quoting centex:
It's going to be a timing thing. I assume Cancun or Cozumel. Early in two days could be a problem.
Just to make you feel better about vacation. May only be travel/air issue not an issue with stay after getting there.
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I've no time to waste with little trolls like wuest who quotes people and changes their posts to weird pointless things. My ignore list is actually empty right now o.o I don't know why I got my hopes up thinking I could actually keep it that way.. sigh.
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Quoting StormW:


Man...glad I'm a forecaster.


LOL

Accuweather is remaining with a more westerly track taking future TS Alex between Tampico and La Pesca, Tamaulipas in Mexico.

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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.
Member Since: July 8, 2005 Posts: 259 Comments: 24574
Quoting TexasHurricane:


how much?




GFS 12Z forecast in 6 days. Notice the offshoot of Alex east of Long Island and another one near the Carolinas.

Quoting futuremet:
This can't be right. The GFS has it stalling for days in the Bay of Campeche.


It sends some energy into the Gulf Stream as well. I'm guessing it's the forecasted shear tearing the storm apart.

Quoting Drakoen:
Something about the way this system look is just too ominous...


It resembles a large WPac storm. The way the SST patterns are set up this year, I think we could see plenty of large hurricanes. Especially in the open Western Atlantic and Gulf.

Quoting whipster:


Agree. Too early, too big.


This is tecnically a Cape Verde system, the way that Katrina was a Cape Verde system but didn't develop until about 75W. This storm has been picking up energy since it left Africa as 92L.

Quoting RecordSeason:
I think the trough will have some affect on this system especially if it gets stronger down the road....I can clearly see a hook into Central or Northern Texas or god forbid i say it Louisiana...

At this size, it doesn't need to go anywhere near Louisiana to cause serious problems. Winds out of the south for days at 25+kts sustained will push massive amounts of storm surge and oil inland.


Especially if it slows down, stalls or turns to the northeast, as it is forecast to do.
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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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