93L near tropical depression strength

By: Dr. Jeff Masters , 25. kesäkuuta 2010 klo 14:31 (GMT)

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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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3729. hcubed
26. kesäkuuta 2010 klo 05:25 (GMT)
Quoting CaneWarning:


I think JFV and IKE could be related? I notice they both have 3 letter names in all caps. Hmmmm.


So does the expressions JFV and LOL.

Both are used when mentioning a joke...
Member Since: 18.05.2007 Posts: 289 Comments: 1639
3728. katadman
26. kesäkuuta 2010 klo 02:02 (GMT)
Quoting HadesGodWyvern:


Alternative ADT cyclone image that shows current dvorak intensity for AL01-2010


Haha Did anyone notice that on the graphic they reference the disturbance as O1L? Looks alot like OIL. Ironic, I think.
Member Since: 7.09.2006 Posts: 0 Comments: 1081
3727. KingofNewOrleans
26. kesäkuuta 2010 klo 01:44 (GMT)
The Mountains of Honduras and Nicaragua are really taking heavy rain now. That's got be mudslide city right now.


The Central Honduran Coast is quite mountainous, got to expect that to be an inhibitor on the to be named Alex once it's raking close along the coast the next 24 hrs.
Member Since: 2.09.2007 Posts: 0 Comments: 110
3726. nrtiwlnvragn
26. kesäkuuta 2010 klo 01:43 (GMT)
Dr Masters has a new blog
Member Since: 23.09.2005 Posts: 13 Comments: 10459
3725. centex
26. kesäkuuta 2010 klo 01:42 (GMT)
The only problem I have is the quoted NW movement. Do they think we are blind? All the relocation stuff does not mean NW. Storms move with the flow, tell me how that is NW? Its plain wrong to quote NW. When it goes S of Cozumel they still will not correct this error tell us how they were right. Goes to show how even experts can and are sometimes wrong. They post WNW track but quote NW movement. Guess it is supposed to move W later when conditions make it go more west when stronger. I just hate this kind of thing.
Member Since: 10.08.2007 Posts: 0 Comments: 3217
3724. AstroHurricane001
26. kesäkuuta 2010 klo 01:40 (GMT)
That central dense hot tower overcast is twice the size of Jamaica. NEW BLOG!!!
Member Since: 30.08.2008 Posts: 8 Comments: 2834
3723. utilaeastwind
26. kesäkuuta 2010 klo 01:39 (GMT)
Quoting ecflweatherfan:
Really, thanks weatherman


your welcome... I think?
Member Since: 12.10.2007 Posts: 0 Comments: 192
3722. ecflweatherfan
26. kesäkuuta 2010 klo 01:29 (GMT)
Really, thanks weatherman
Member Since: 19.03.2010 Posts: 0 Comments: 1146
3721. ecflweatherfan
26. kesäkuuta 2010 klo 01:28 (GMT)
Depends for how long it sits there, and how strong/weak the system is as to where it will go.
Member Since: 19.03.2010 Posts: 0 Comments: 1146
3719. utilaeastwind
26. kesäkuuta 2010 klo 01:27 (GMT)
Quoting F4PHANTOM:
Wouldn't a slower forward speed have a tendency is allow TD1 to drift more westward ?


Once the LLC is solid we will start seeing the rightward motion. Without the LLC it can keep drifting west.
Member Since: 12.10.2007 Posts: 0 Comments: 192
3718. AstroHurricane001
26. kesäkuuta 2010 klo 01:27 (GMT)
Quoting Michfan:


Wow, the MAIN storm area is now 10 deg wide. The storm just keeps converging and expanding into its own feeder bands.

Quoting taco2me61:
Well with all due respect, If this storm hits the Texas coast it will bring Oil not only to LA but MS, AL and FL will get the Oilly Mess.... Because of the counter clock wise movement the waves from the east side of the storm move north. So all the oil just to the south of FL,AL and MS will move north....

Taco :o(


I'd hate to think how the toxic sludge will affect the wetlands and some of the whitest beaches in the world. If the oil becomes concentrated this could heat up the northeastern Gulf further.
Member Since: 30.08.2008 Posts: 8 Comments: 2834
3717. weatherman566
26. kesäkuuta 2010 klo 01:26 (GMT)
Blog slowed down because Dr. Masters just released a new blog.
Member Since: 15.07.2008 Posts: 0 Comments: 108
3714. TexasGulf
26. kesäkuuta 2010 klo 01:26 (GMT)
Quoting HaboobsRsweet:
The news story I saw said BP would have to if the storm became a threat...not that they were shutting down. They did say the cap would come off and takes 5 days to move everything out.


Yes... and it takes 5-days to move everything back. During that 10-day period, the pipe will keep discharging 700,000+ gallons/day of oil into the gulf.

I actually think BP can move out within a 3-day window if needed. The problem they will have is that this is an active season. They will have to mob-demob several times during the summer. This is going to get old really fast. If there is enough of a wave train coming through the Caribbean into the Gulf... they could even just suspend operations for a month or so.

The oil spill disaster is getting ready to move up to a new level of BAD!

Member Since: 28.04.2008 Posts: 0 Comments: 354
3713. ecflweatherfan
26. kesäkuuta 2010 klo 01:25 (GMT)
Quoting RecordSeason:
Based on the last several frames of infrared, along with Dr. Master's blog update and simply the sheer size of this storm combined with it's angle of motion, I have a feeling we are going to hear some terrible reports of flooding in central America.

This is by far some of the most powerful convection I've ever seen in anything that wasn't at least a hurricane.


I know they have mentioned the DR today... imagine for a second, this storm over Haiti, pounding away. All those areas down there really suffer with each tropical system that threatens (whether full force or just fringe effects).
Member Since: 19.03.2010 Posts: 0 Comments: 1146
3712. 1965
26. kesäkuuta 2010 klo 01:23 (GMT)
Quoting MiamiHurricanes09:
True but a gust of 150 miles an hour causes more turbulence than a gust of 50 miles per hour.


Wasn't Dr Masters HH almost lost in Hurricane Hugo? If memory serves, a HH went down in Janet with loss of the entire crew. Penetrating a majors eyewall is serious business from what I have read.
Member Since: 17.08.2009 Posts: 0 Comments: 46
3710. ecflweatherfan
26. kesäkuuta 2010 klo 01:22 (GMT)
If I am not mistaken, someone correct me if I am wrong about the models... but the early models are the statistical models (BAM, LBAR, etc.). The later models are the skilled models (GFS, ECM, etc.). The early models are first to "publish" so to speak. To put it simply, anyways.
Member Since: 19.03.2010 Posts: 0 Comments: 1146
3709. nrtiwlnvragn
26. kesäkuuta 2010 klo 01:20 (GMT)
Quoting F4PHANTOM:
Could someone explain the difference between "Early cycle NHC model tracks and late cycle NHC model tracks"?


b. Early versus Late Models

Forecast models are characterized as either early or late, depending on whether they are available to the forecaster during the forecast cycle. For example, consider the 1200 UTC forecast cycle, which begins with the 1200 UTC synoptic time and ends with the release of an official forecast at 1500 UTC. The 1200 UTC run of the NWS/Global Forecast System (GFS) model is not complete and available to the forecaster until about 1600 UTC, an hour after the forecast is released. Thus, the 1200 UTC GFS would be considered a "late" model since it could not be used to prepare the 1200 UTC official forecast. Conversely, the BAM models are generally available within a few minutes of the time they are initialized. Therefore, they are termed "early" models. Model timeliness is listed in Table 1.

Due to their complexity, dynamical models are generally, if not always, late models. Fortunately, a technique exists to take the latest available run of a late model and adjust its forecast so that it applies to the current synoptic time and initial conditions. In the example above, forecast data for hours 6-126 from the previous (0600 UTC) run of the GFS would be smoothed and then adjusted, or shifted, so that the 6-h forecast (valid at 1200 UTC) would match the observed 1200 UTC position and intensity of the TC. The adjustment process creates an "early" version of the GFS model that becomes part of the most current available guidance for the 1200 UTC forecast cycle. The adjusted versions of the late models are known, largely for historical reasons, as "interpolated" models.

Link
Member Since: 23.09.2005 Posts: 13 Comments: 10459
3708. reedzone
26. kesäkuuta 2010 klo 01:20 (GMT)
Looking at the latest IR, TD1 has an....eye LOL, or at least a roundish small dry spot right at the center ;)
Member Since: 1.07.2008 Posts: 13 Comments: 7334
3705. ecflweatherfan
26. kesäkuuta 2010 klo 01:18 (GMT)
Latest imagery sure looks sweet though... really getting its act together. I was kinda doubting it yesterday, but it made a lot of progress today.
Member Since: 19.03.2010 Posts: 0 Comments: 1146
3704. utilaeastwind
26. kesäkuuta 2010 klo 01:18 (GMT)
Quoting F4PHANTOM:
Why do you say that? Has reported forward speed decreased?


It looks like the westward motion had decreased. I believe Alex is slowing and will then start a rightward motion.

However, I am not a PRO.
Member Since: 12.10.2007 Posts: 0 Comments: 192
3703. ecflweatherfan
26. kesäkuuta 2010 klo 01:16 (GMT)
Yeah kinda a lull in the action. I guess people are just watching and waiting right noww for the 11pm update. Then the blog will light up as usual with the "I told you so's"... "See I told you it was coming to (this state)" LOL!
Member Since: 19.03.2010 Posts: 0 Comments: 1146
3700. weathermancer
26. kesäkuuta 2010 klo 01:13 (GMT)
Quoting WinterAnalystwx13:
Looks like the blog slowed down a lot...


noticed that too! Time is standing still!!!!!

LOL
Member Since: 29.08.2009 Posts: 12 Comments: 482
3697. utilaeastwind
26. kesäkuuta 2010 klo 01:09 (GMT)
Looks like Alex is hitting the breaks. SLOWING DOWN.
Member Since: 12.10.2007 Posts: 0 Comments: 192
3696. Gorty
26. kesäkuuta 2010 klo 01:09 (GMT)
Can turbulnace be consider wind shear?
Member Since: 8.11.2008 Posts: 12 Comments: 1058
3695. HaboobsRsweet
26. kesäkuuta 2010 klo 01:08 (GMT)
Quoting weatherman566:


The reason I said this is because I had a hurricane Hunter talk to my school about flying into hurricanes, and he said it was definately a lot scarier to fly into a depression/disturbance/storm than into a hurricane. He told us horror stories about flying into a depression one time. He also mentioned that flying into a hurricane was really easy. When I heard this, i was surprised as well. Really interesting!

The uniform flow around a hurricane makes it much more calm in regards to turb while depressions are so scattered you see rapid change in speed and direction since it is so disorganized meaning more turb.
Member Since: 20.05.2009 Posts: 0 Comments: 1640
3694. HaboobsRsweet
26. kesäkuuta 2010 klo 01:05 (GMT)
Quoting sailingallover:

not over the water, not much anyway..this being based on being in boats in ones.
on land near any kind of hills and even in the ICW in florida the turbulence can be bad.. on the hilly islands of the caribbean it can be DEVASTATING.

yes because he hills and mountains cause a change in direction just like mountain wave turb. This also changes the speed. Forces the air up and gives you a tigher gradiant increasing speed near the mountain.
Member Since: 20.05.2009 Posts: 0 Comments: 1640
3693. gordydunnot
26. kesäkuuta 2010 klo 01:04 (GMT)
Oh I am sorry can't use the excuse I accidentally locked in the caps . As Steve Martin would say WELL EXCUSE ME!!!(3661)
Member Since: 18.08.2008 Posts: 0 Comments: 3109
3692. bwt1982
26. kesäkuuta 2010 klo 01:03 (GMT)
Liking what I see with these models more and more! Not looking good for Mexico or Central America. Good thing is looks like TD one will mostly be a rain event and just a little wind.
Member Since: 29.09.2008 Posts: 0 Comments: 143
3691. KEEPEROFTHEGATE (Mod)
26. kesäkuuta 2010 klo 01:03 (GMT)
XXX
Member Since: 15.07.2006 Posts: 163 Comments: 52230
3690. utilaeastwind
26. kesäkuuta 2010 klo 01:03 (GMT)
Quoting IKE:
I'm surprised there aren't warnings for the northern coast of Honduras. The center is near the coast.


Me too. I am on the island Utila on The Bay Islands of Honduras (16.10 86.9N). Our local news is issuing alerts, however.

Good think we are not relying on the NHC!
Member Since: 12.10.2007 Posts: 0 Comments: 192
3689. HaboobsRsweet
26. kesäkuuta 2010 klo 01:02 (GMT)
Quoting MiamiHurricanes09:
True but a gust of 150 miles an hour causes more turbulence than a gust of 50 miles per hour.

It is the delta that you have to worry about aka the change. If the gust spread is 25kts sustained to 50kts then you will have more than in a hurricane of 140kts gusting 150kts. This is why Tstorms are a major no no to fly in. You can fly in hurricanes.
Member Since: 20.05.2009 Posts: 0 Comments: 1640
3688. all4hurricanes
26. kesäkuuta 2010 klo 01:02 (GMT)
I think it's funny td1 hasn't existed for 5 hours and it has it's own wiki page
Member Since: 29.03.2008 Posts: 0 Comments: 2338
3687. sailingallover
26. kesäkuuta 2010 klo 01:01 (GMT)
Quoting HaboobsRsweet:

I do not htink that is 100% true. A hurricane actually does not have a lot of turblance because it is uniform and the speed is similar around the same path. To have turblence you need rapid change in speed or direction and that doesnt really happen much in a hurricane.

not over the water, not much anyway..this being based on being in boats in ones.
on land near any kind of hills and even in the ICW in florida the turbulence can be bad.. on the hilly islands of the caribbean it can be DEVASTATING.
Member Since: 1.09.2009 Posts: 23 Comments: 1005
3686. ecflweatherfan
26. kesäkuuta 2010 klo 01:01 (GMT)
IKE, in a sense I am kinda surprised too... However, it may be because of the strongest winds are located north of the center. There would be no need for a Tropical Storm Warning in that case. Though I bet they may be getting Tropical Storm force wind gusts in squalls.
Member Since: 19.03.2010 Posts: 0 Comments: 1146
3685. MiamiHurricanes09
26. kesäkuuta 2010 klo 01:01 (GMT)
Quoting extreme236:


Ike has the most advanced JFV detector this blog's ever seen.
It isn't difficult, lol. When StormW comes on he will refer to him as "teh senior chief". And he won't call me MH09 or anything like that, he'll call me "cane" or "brickell boy".
Member Since: 2.09.2009 Posts: 130 Comments: 21032
3684. Gorty
26. kesäkuuta 2010 klo 01:01 (GMT)
@Miamihurricanes

13! Wow!

Are you a tropical weather prodigy? lol.
Member Since: 8.11.2008 Posts: 12 Comments: 1058
3683. Seastep
26. kesäkuuta 2010 klo 01:00 (GMT)
Unless someone can answer my earlier question, forget the current model run.

Darby never goes below 1008mb... the entire run.

Not a true (not even close) representation of the atmosphere.
Member Since: 9.09.2008 Posts: 6 Comments: 3412
3682. mara0921
26. kesäkuuta 2010 klo 01:00 (GMT)
NEW BLOG FOLKS
Member Since: 23.11.2009 Posts: 0 Comments: 19
3681. IKE
26. kesäkuuta 2010 klo 01:00 (GMT)
Quoting CaneWarning:


LOL how'd you guess already?


Teh cluz wear meny.
Member Since: 9.06.2005 Posts: 23 Comments: 37858
3680. weathermancer
26. kesäkuuta 2010 klo 01:00 (GMT)
Quoting CybrTeddy:


94L might have a shot


Yep. Fish-spinner?

Also that large wave off from Africa the last 2 days.
Member Since: 29.08.2009 Posts: 12 Comments: 482
3679. weatherman566
26. kesäkuuta 2010 klo 01:00 (GMT)
Quoting MiamiHurricanes09:
True, but when in a hurricane you are experiencing much stronger turbulence than in a tropical depression, per se. Yes it is calm when you are in the eye, but what if it is needed to analyze the eye wall?


The reason I said this is because I had a hurricane Hunter talk to my school about flying into hurricanes, and he said it was definately a lot scarier to fly into a depression/disturbance/storm than into a hurricane. He told us horror stories about flying into a depression one time. He also mentioned that flying into a hurricane was really easy. When I heard this, i was surprised as well. Really interesting!
Member Since: 15.07.2008 Posts: 0 Comments: 108

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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.

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