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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Satellite presentation continues to improve and it's starting to throw off some bands on the east side. NW movement pronounced at the present time. 93L really isn't far at all from being not only a TD, but Alex.

Link
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Hurricane hunters now going back to the COC.




SEE GUYS WHAT DID I TELL YOU
Member Since: May 21, 2006 Posts: 5089 Comments: 114062
Quoting Baltimorebirds:
No that belongs to danny from 2009.That was a discusting storm.


That belongs to Dolly or Fay actually. Moderate TS force winds, great organization, no LLC, took forever to be named.
Member Since: July 8, 2005 Posts: 259 Comments: 23012
This will have it's best chance of intensification When center reaches 85 West.
Member Since: Posts: Comments:
1724. Levi32
Winds at Puerto Lempira, Honduras are still out of the north to northwest during the past couple of hours.

Member Since: November 24, 2005 Posts: 628 Comments: 26455
1723. IKE
Quoting NOLALawyer:


Sometimes I find you quite delusional, Ike. Or, are you just the perpetual turd in the punchbowl?


It's just the weather.
Member Since: Posts: Comments:
Quoting ElConando:


Not just you but a common thunderstorm looks dangerous on rainbow.


lol true
Member Since: Posts: Comments:
Hurricane hunters now going back to the COC.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Been out for a while, can anyone tell me what is going on whith 93L? Also what direction do the models show it going? Thanks All!
Member Since: Posts: Comments:
Quoting Hurricanes101:
93L to me looks much more impressive on rainbow or avn loops than on visible lol

thats just me though


Not just you but a common thunderstorm looks dangerous on rainbow.
Member Since: September 6, 2009 Posts: 2 Comments: 3709
It's so funny reading the reasons why it's not declared a TD yet. Over the years, my favorites:
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1. The pilot didn't know where he was..missed the center..lol
.
.
2. It really is a TD but they don't want us to know
.
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3. It's going to be a TD the moment the plane leaves
.
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4. NHC doesn't know how to read the data correctly
Member Since: Posts: Comments:
1715. 900MB
Does anyone have a link to the Google Earth recon map?
Thanks!
Member Since: June 11, 2006 Posts: 0 Comments: 643
1714. OneDay
Too broad a low pressure area. It won't be able to close off and wrap up quick enough to not be severely impacted by land. Plus it is far enough south that it will be traversing quite a bit of Mexican real estate. We'll probably have an open wave in the Bay of Campeche early next week at best. (Which is fine by me :-)
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Quoting TexasHurricane:


Lol TEX! PERFECT! It could go anywhere. :)
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93L to me looks much more impressive on rainbow or avn loops than on visible lol

thats just me though
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1711. FMDawg
Quoting WinterAnalystwx13:


I want to say A, but its probably going to be B. I'll say A/B


c
Member Since: Posts: Comments:
1709. GetReal
After closely observing the low level cloud field movement, I would place the "center" of 93L at 17N and 82.5W, and moving WNW to NW...

There is my $.02 worth of input.
Member Since: Posts: Comments:
guys the hh is not even done yet there makeing other pass
Member Since: May 21, 2006 Posts: 5089 Comments: 114062
1707. 900MB
Quoting Levi32:


A system this weak won't be attracted to the warmer water because the surface ocean temperature is for all practical purposes uniform across the western Caribbean, and a tropical depression or tropical storm won't be upwelling anything colder than that. In other words, the system isn't strong enough to even need the really deep warmth. The shallow layer will fuel it just fine for now. It won't run for something that's too big for it to eat.


Sure, come back at me with the "it won't run for something too big to eat" theory :)

I am just wondering if there is something that may nudge it a tad north or east. Maybe the "bouncing off the mountain" theory. Funny part is that I am not entirely joking- a strong storm has a tendency to move to follow the easiest path. But, point taken, it is not that kind of storm yet.
Member Since: June 11, 2006 Posts: 0 Comments: 643
This is the nastiest looking INVEST I have ever seen...

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Member Since: Posts: Comments:
1704. Levi32
Notice the 18z position is north of most of the earlier model initializations.

Member Since: November 24, 2005 Posts: 628 Comments: 26455
Quoting Tazmanian:




YES YES YES SO WE CAN GET THE A NAME OUT OF THE WAY


You obviously do not live on the Gulf Coast and are out of touch with reality.
Quoting IKE:
So no TD?

I've got a few extra towels if anyone needs one to wipe away the t e a r s......


Sometimes I find you quite delusional, Ike. Or, are you just the perpetual turd in the punchbowl?
Member Since: Posts: Comments:
1324 MiamiHurricanes09 "You can really see the northwesterly motion."

While I don't like it:
Easterly is coming from the east and heading toward west;
Westerly is coming from the west and heading toward the east;
Northerly is coming from the north and heading toward the south;
Southerly is coming from the south and heading toward the north.
A nor'easter comes from the northeast and heads toward the southwest.
From which we must deduce that a northwesterly is coming from the northwest and heading toward the southeast. Which was the opposite of your intent, "You can really see the northwestward motion."
Though I can't from the loop you posted.
What I saw are winds heading due west from Cuba to the Yucatan.

And a storm more likely to die in the mountains trying to get to the Gulf of Tehuantepec than one heading toward the Gulf of Mexico.

Note, this is what I saw in the loop... and has nothing whatsoever to do with present&future steering, path projections, or what the storm will most probably do.
Member Since: Posts: Comments:
Quoting SirCane:
Here comes trouble. It's busting out! Should be Alex by 11PM I'd say.



HMMMM JFV???
Member Since: May 21, 2006 Posts: 5089 Comments: 114062
1699. xcool
93l bigbig
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1698. SirCane
Here comes trouble. It's busting out! Should be Alex by 11PM I'd say.
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I'm out for now, I'll be back later in a few hours..
Member Since: Posts: Comments:
Quoting cchsweatherman:
Lets allow the Hurricane Hunters to finish flying through the system and collecting all the data before jumping to conclusions.


Are you stark raving mad? I might get work done if the list got that quiet. ;)
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Where are the poofcasters now?
Member Since: Posts: Comments:
Quoting ezcColony:


We had a discussion some couple of hours ago about a spin to 93L. Are you willing to admit that you were incorrect now that real data has been released that showed no closed low?

Surprised someone is willing to say it isnt closed yet. They dotn always hit the center with the first pass. Small Plane big low. When they come back through the center you may be surprised to wind west winds.
Member Since: May 20, 2009 Posts: 0 Comments: 1640
Quoting StSimonsIslandGAGuy:
What was the lowest pressure found?


1005 mb.
Member Since: July 8, 2005 Posts: 259 Comments: 23012
Quoting hurricanejunky:


Oh that's definitely Oz! Welcome back! Only you would direct me to a disgusting political hack attack.


Sorry. You've got me mistaken for the guy here that did the hurricane videos. I am a subscriber to his YouTube channel but I am not him. Although my name is not posted on that link, I participate in that blog I provided to you.
Member Since: Posts: Comments:
1689. unf97
Good stuff on WWL with Dr. Masters on Spud McConnell's talk program.
Member Since: Posts: Comments:
Quoting iluvjess:


Are you wanting it to develope??




YES YES YES SO WE CAN GET THE A NAME OUT OF THE WAY
Member Since: May 21, 2006 Posts: 5089 Comments: 114062
When should we get the report from the hurricane hunters?
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Quoting Hurricanes101:


I do find it kind of funny how many posts were omg TD by recon, we may even have a TS

and yet they dont even find a closed low lol


"dont even find a closed low"

You make it sound like there's a lot more than that thing that it needs, when I'm pretty sure that's the only thing left it needs.. lol
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1684. Patrap
Quoting Thunderground:
Great to hear ya Pat!!! You done learned Spud some meteorology



I seems to warm up to Actors.

LOL

Ive met Spud a few times Post K at Events here.

Hes a riot.

Member Since: July 3, 2005 Posts: 415 Comments: 125628
Quoting ezcColony:


We had a discussion some couple of hours ago about a spin to 93L. Are you willing to admit that you were incorrect now that real data has been released that showed no closed low?


I agree with some of the bloggers on here that say they missed a pass, let's wait till they are done investigating the system. Nothing is written in stone, it's either closed or not closed.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting Seflhurricane:
hopefully recon finds west winds with the next pass if not looks like no upgrade till tomorrow may even go strait through to TS Alex


Are you wanting it to develope??
1680. scott39
When you zoom in on the visible Sat, you can see the COC moving! I did not say eye. LOL
Member Since: June 13, 2009 Posts: 0 Comments: 6706
Quoting StSimonsIslandGAGuy:
What was the lowest pressure found?


1005mb
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About JeffMasters

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