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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1878. cg2916
8:21 PM GMT on June 25, 2010
I don't think it'll be Alex 5 PM, it'll probably be 5:30 or 6:00, because they wanna go back all the way through the system.
Member Since: December 21, 2007 Posts: 13 Comments: 3046
1876. txsweetpea
8:21 PM GMT on June 25, 2010
Are any of the models showing a northern tx event?
Member Since: June 7, 2010 Posts: 0 Comments: 546
1875. Tazmanian
8:21 PM GMT on June 25, 2010
the stronger the storm the more it gos N and if 93L is now starting at 40mph it has a better ch of going N
Member Since: May 21, 2006 Posts: 5091 Comments: 115439
1874. matt03blueoptima
8:21 PM GMT on June 25, 2010
hello people.. seems like were off a great start on this season.. i just hope no major damages are going to occur. i live in houston. ill keep an eye on this. taz, patrap, stormw nice to see yall again. u too drakoen
1873. hydrus
8:20 PM GMT on June 25, 2010
Quoting itrackstorms:
I'm setting the table... anybody care to join me?

ALEX maybe?




This post just made my day. Thank you.
Member Since: September 27, 2007 Posts: 1 Comments: 22317
1872. fmbill
8:20 PM GMT on June 25, 2010
Quoting helove2trac:
we now have ts alex


Not without a vortex message.
Member Since: May 27, 2008 Posts: 0 Comments: 468
1871. CybrTeddy
8:20 PM GMT on June 25, 2010
Quoting Baltimorebirds:
and also the focus attention was also on bertha.....


Trust me, no it wasn't. At that point Bertha was a moderate TS well past Bermuda. People where on Dolly as much as they are on 93L.
Member Since: July 8, 2005 Posts: 259 Comments: 24553
1869. watchingnva
8:20 PM GMT on June 25, 2010
Quoting JDSmith:


You people have no sense of humor.


i have a huge sense of humor actually...ask my wife...that has became much more than humor at times, especially over the last few weeks...and like i said...just for a few hours...lol...dont get your panties in a bind...

93 wants so badly to become alex...but it has to stop pulling a dolly to do that...lol
Member Since: September 7, 2005 Posts: 7 Comments: 1525
1867. 7544
8:19 PM GMT on June 25, 2010
if 93l inches more north looks like it going that way it could start to explode and the more north it goes throw out those models we can see a whole new track . what will this look like at dmax . dont miss this one .
Member Since: May 6, 2007 Posts: 0 Comments: 6874
1865. PensacolaGirl
8:18 PM GMT on June 25, 2010
My family is leaving for Cancun tomorrow morning. Any opinons on flights being delayed from Miami? We are escaping the oil and now headed for a possible TS.
1864. helove2trac
8:18 PM GMT on June 25, 2010
we now have ts alex
1863. unf97
8:18 PM GMT on June 25, 2010
Quoting RecordSeason:
Low level circulation is incredibly large on this thing.

When it gets away from land it's going to fill in almost the entire space between Mexico, central America, and Cuba with convection.

You can see surface winds out of the east and east-northeast associated with the system as far north as the tip of the Yucatan. It is going to pull in all that convection up there, and continue expanding to the rear also as it pulls away from land.


Yes, I am impressed with the size of the circulation as well. This may be one of the main reasons for such a good period of time for one main COC to develop and close off. It's about to achieve it though, if it hasn't already. HH will confirm this very soon if it has indeed closed off a COC.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
1862. CosmicEvents
8:18 PM GMT on June 25, 2010
Quoting Levi32:


Lol yeah....remember in 2008 I think we had one of these in the central Caribbean with 45-knot winds but couldn't get named because it wasn't closed. I don't remember if it ever developed or not.

I remember that one. A few friendships were lost amongst the uproar and disputes. I think we even had a couple of divorces. Some bloggers get at their testiest during the time between "L" and "TD".
Member Since: August 3, 2005 Posts: 10 Comments: 5680
1861. tennisgirl08
8:17 PM GMT on June 25, 2010
Quoting TexasHurricane:


Like how far north? just curious...


Just my opinion...as far north as LA/MS/AL. The reason I think this is that 93L is going to be a large system that is going to strengthen over the next few days. A larger system and stronger system will be affected more by the trough. Most northern gulf coast areas will get something from this system, even if just rain.

I am not at all buying into a TX/MX event.
Member Since: July 17, 2008 Posts: 0 Comments: 1242
1860. MiamiHurricanes09
8:16 PM GMT on June 25, 2010
Quoting Levi32:
Max surface winds remain solidly around 35 knots as the recon plane passes through the NE quad back towards the center.
35 knots will still equal to tropical storm status. I think we will find those west winds this time around.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1858. louisianaboy444
8:16 PM GMT on June 25, 2010
Link

Read it and tell me what you think...I am only but an Amateur so i am prepared for criticism or correction in my analysis
Member Since: August 29, 2006 Posts: 22 Comments: 1352
1857. TexasHurricane
8:16 PM GMT on June 25, 2010
Quoting btwntx08:

uh ohhh dolly all over again??? lol


So if we have another Dolly, does that mean we will have another Rita? :)
Member Since: July 2, 2009 Posts: 0 Comments: 2811
1856. JDSmith
8:16 PM GMT on June 25, 2010
Quoting watchingnva:


bye taz...ill check back on ya tomorrow...


You people have no sense of humor.
Member Since: August 15, 2008 Posts: 0 Comments: 103
1855. itrackstorms
8:16 PM GMT on June 25, 2010
I'm setting the table... anybody care to join me?

ALEX maybe?




Member Since: July 20, 2008 Posts: 0 Comments: 152
1854. Levi32
8:16 PM GMT on June 25, 2010
Quoting Drakoen:


Looks like it wants to become a large system. Look at all that ourflow to the north


Yeah, that nice upper-level anticyclone over it should allow it to expand nicely.
Member Since: November 24, 2005 Posts: 635 Comments: 26699
1853. WPBHurricane05
8:16 PM GMT on June 25, 2010
Both Dolly and Fay were tropical storms on there first advisory. Fay formed over Hispaniola.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
1851. stormpetrol
8:15 PM GMT on June 25, 2010
The weather here in Grand Cayman is going downhill fast too!!
Member Since: April 29, 2007 Posts: 0 Comments: 8134
1849. Levi32
Max surface winds remain solidly around 35 knots as the recon plane passes through the NE quad back towards the center.
Member Since: November 24, 2005 Posts: 635 Comments: 26699
1847. bwi
17n 81.5w
Continuous Winds TIME
(EDT) WDIR WSPD
3:50 pm S ( 179 deg ) 26.4 kts
3:40 pm S ( 180 deg ) 27.6 kts
3:30 pm S ( 174 deg ) 29.1 kts
3:20 pm S ( 177 deg ) 31.3 kts
3:10 pm SSE ( 158 deg ) 26.0 kts
3:00 pm SE ( 146 deg ) 25.1 kts
Member Since: Posts: Comments:
Quoting 92Andrew:
I have a question, and hopefully bloggers aren't too busy to answer. So... how do we know the storm is moving NW ? I've read a few comments on this thing by the upper echelon of bloggers who say its moving NW. How do we know?


Check your WUmail...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting Drakoen:


Looks like it wants to become a large system. Look at all that ourflow to the north
Not good.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1843. bwt1982
Checking back in today. I see not much has changrd from yesterday. 93L will get going but will have a tough time when it gets close to the Yucatan. I love this high pressure over Florida! It kept 93L away from us here in S Fla! 94L will be a fish so as usual it looks good for Florida! It iwll be interesting to see if 93L can make it to be Alex before it dies out over land? We shall see!
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Quoting Drakoen:
If this isn't a tropical storm is is a very powerful wave lol...

I totally agree with that, I think this will be declared a 45mph storm by 5pm this evening, it is also pulling more north and intensifying and organizing by the minute, don't like it one bit, it's too close for comfort!
Member Since: April 29, 2007 Posts: 0 Comments: 8134
Quoting Tazmanian:
TS today cat 5 may be by sunday


94L today cat 5 by monday


bye taz...ill check back on ya tomorrow...
Member Since: September 7, 2005 Posts: 7 Comments: 1525
42mph winds found at 17.033N 81.650W.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
.
Member Since: May 21, 2006 Posts: 5091 Comments: 115439
1836. Drakoen
Quoting Levi32:
The empty places where convection has been lacking within 93L's circulation are gradually filling in with new thunderstorms as time goes on.



Looks like it wants to become a large system. Look at all that ourflow to the north
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1835. Levi32
Quoting HurricaneSwirl:


Are you thinking of Dolly?


Maybe....I wasn't focusing very much on her during her development stages so I could be thinking of her.
Member Since: November 24, 2005 Posts: 635 Comments: 26699
drak,second that,right to td status probably around 8pm,won't have time for the 5pm IMO
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1833. scott39
How much longer until HH are done?
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1831. centex
Quoting 92Andrew:
I have a question, and hopefully bloggers aren't too busy to answer. So... how do we know the storm is moving NW ? I've read a few comments on this thing by the upper echelon of bloggers who say its moving NW. How do we know?
NHC said couple hours ago it was forecast to move WNW. Just now getting good center so pinpointing direction won't be an average or guess on-going. To me looks like WNW currently.
Member Since: Posts: Comments:
1830. fmbill
Quoting Unfriendly:
Taz, you completely destroyed any respect I, and I'm sure others, had for you during the last few weeks - you are nothing more then a troll at this point.

*poof*


What? Really? You have got to be kidding!
Member Since: May 27, 2008 Posts: 0 Comments: 468
1829. Levi32
The empty places where convection has been lacking within 93L's circulation are gradually filling in with new thunderstorms as time goes on.

Member Since: November 24, 2005 Posts: 635 Comments: 26699

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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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