93L slow to develop, but bringing heavy rains to Haiti

By: Dr. Jeff Masters , 1:50 PM GMT on June 22, 2010

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A modest region of intense thunderstorms (Invest 93L) is over the central Caribbean, a few hundred miles south of Hispaniola. This disturbance has the best chance to become Tropical Storm Alex of any system we've seen so far this year. We don't have any buoys near 93L, but pressures at the ground stations surrounding the storm are not falling. A pass of the ASCAT satellite over the Central Caribbean at 9:45 pm EDT last night revealed a modest wind shift associated with 93L, but nothing at all close to a surface circulation. Top surface winds seen by ASCAT were 15 - 20 mph. Water vapor satellite loops show that 93L is embedded in a large region of moist air. The atmosphere over the Caribbean has moistened over the past day, which should aid development of 93L. Wind shear is a low 5 - 10 knots. The high wind shear associated with the strong winds of the subtropical jet stream are over the northern Caribbean, too far north to interfere with development, but close enough to provide good upper-level outflow for the storm. Visible satellite loops show high level cirrus clouds streaming away from 93L to the northeast, evidence of the upper-level outflow channel that is developing to the storm's north. Sea Surface Temperatures are plenty warm, a record 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 Madden-Julian oscillation is a pattern of enhanced rainfall that travels along the Equator from west to east. The pattern has a wet phase with large-scale rising air and enhanced thunderstorm activity, followed by a dry phase with large-scale sinking air and suppressed thunderstorm activity. Each cycle lasts approximately 30 - 60 days. When the Madden-Julian oscillation is in its wet phase over a hurricane-prone region, the chances for tropical storm activity are greatly increased. The main negative for 93L continues to be lack of spin. The University of Wisconsin 850 mb relative vorticity analysis is showing that spin at 850 mb (roughly 5,000 feet in altitude) has increased over the past day, but 93L needs to acquire additional spin before it can grow more organized. I speculate that it is this lack of spin that contributed to the loss of much of 93L's heavy thunderstorm activity last night. The storm is now going through a cycle where it is building another respectable mass of heavy thunderstorms, and the increased inflow of low-level air that will feed these thunderstorms will likely enhance 93L's spin today. The Hurricane Hunters are on call to investigate 93L on Wednesday afternoon.


Figure 1. Morning visible satellite image of the central Caribbean disturbance 93L.

Forecast for 93L
NHC is giving 93L a 40% chance of developing into a tropical depression by Thursday morning, which is a reasonable forecast. Given the storm's current lack of spin and relatively modest amount of heavy thunderstorms, the earliest I'd expect 93L to become a tropical depression would be Wednesday afternoon, with Thursday more likely. Wind shear is expected to be low, less than 10 knots, over the central and western Caribbean this week. Water temperatures will be warm, dry air absent, and the MJO favorable. I don't see any major impediments to the storm becoming a tropical depression by Thursday, and it is a bit of a surprise to me that the computer models have been reluctant to develop 93L. The GFS, NOGAPS, and UKMET models do not develop 93L, and the ECMWF model doesn't develop 93L until after it crosses the Yucatan Peninsula and enters the Gulf of Mexico in a about a week. The current (2am EDT) run of the GFDL model predicts 93L will be a weak tropical storm in the Gulf of Mexico in five days; its previous run had 93L as a major hurricane in the Gulf. Given all this model reluctance and the current disorganization of 93L, I give the storm a low (less than 20% chance) of becoming a hurricane in the Caribbean. Expect 93L to bring flooding rains of 3 - 6 inches to Jamaica, eastern Cuba, and southwestern Haiti today through Wednesday. These rains will spread to the Cayman Islands and central Cuba by Thursday, and western Cuba and Mexico's Yucatan Peninsula on Friday. The current run of the SHIPS model has 93L slowing down late this week to a forward speed of just 6 knots (7 mph) from its current speed of about 10 mph, in response to a weakening in the steering currents. A trough of low pressure is expected to swing down over the Eastern U.S. early next week. 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 in the oil spill region. This is the solution of the Canadian GEM model. If 93L stays weak and/or the trough is not so strong, the storm would get pushed west-northwestwards towards the Texas coast. This is the solution of the ECMWF model. The amount of wind shear in the Gulf of Mexico next week is highly uncertain. There is currently a band of high shear near 30 knots over the Gulf, and some of the models predict this shear will remain over the Gulf over the next 7 - 10 days. However, other models predict that this band of high shear will retreat northwards and leave the Gulf nearly shear-free. The long-term fate of 93L remains very murky. My main concerns at this point are the potential for 3 - 6 inches of rain in Haiti over the next two days, and the possibility 93L could become a hurricane in the Gulf of Mexico next week.

Elsewhere in the tropics
None of the reliable computer models is calling for tropical cyclone formation elsewhere in the Atlantic over the next seven days.

Floods in China and Burma kill over 250
The deadliest and most destructive weather-related disaster on the planet so far this year is occurring in southern China and northern Burma, where a week of heavy rains has caused flooding that has claimed over 250 lives. The heavy rains and floods ravaging 10 southern Chinese provinces had killed 199 and left 123 missing as of 11:00 a.m. Tuesday, a Ministry of Civil Affairs statement said. Damage is estimated at $6.2 billion. Floods and landslides in neighboring areas of Myanmar (Burma) have claimed at least 63 lives in the past week.


Figure 2. Paramilitary policemen help evacuate residents from Wanjia village of Fuzhou City, East China's Jiangxi province, June 22, 2010. Days of heavy rain burst the Changkai Dike of Fu River on June 21, threatening the lives of 145,000 local people. Local authorities have ordered immediate evacuation, and the army and paramilitary police have begun conducting rescue operations. Image credit: Xinhua.

Wind and ocean current forecast for the BP oil disaster
Southeast to east winds less than 10 knots will blow in the northern Gulf of Mexico today through Saturday, according to the latest marine forecast from NOAA. The resulting weak ocean currents should cause little motion of the oil slick, according to the latest trajectory forecasts from NOAA and the State of Louisiana. The long range outlook is uncertain, and will depend upon what 93L does.

Resources for the BP oil disaster
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 allows one 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

"Hurricane Haven" airing again this afternoon
Tune into another airing of my live Internet radio show, "Hurricane Haven", at 4pm EDT today. Listeners will be able to call in and ask questions. The call in number is 415-983-2634, or you can post a question in the comments area on my blog. You can also email the questions to me today before the show: jmasters@wunderground.com. Be sure to include "Hurricane Haven question" in the subject line. Some topics I'll cover today on the show:

1) The latest on 93L
2) Which model is the most reliable?

Today's show will be 30 - 40 minutes, and you can tune in at http://www.wunderground.com/wxradio/wubroadcast.h tml. The show will be recorded and stored as a podcast.

Jeff Masters

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Quoting Drakoen:


Yup. Mentioned it earlier when I was trying to figure out why the NHC lowered its chances.



Quite a small system it is now.
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Quoting DDR:
Good evening
Rain/floods here in Trinidad today,Is anyone else watching that wave in the Central Atlantic?

Yes...all of them.. we lucked out with the wave that went over you last night and today it lost all it's convection yesterday evening.

You have another one day after tomorrow that so far has no rotation at all..but it's got a lot of convection going..

Then one out by 35-40W.. this one worries me because it has a low pressure trough just to it's north which appears to be enhancing it, giving it rotational energy and sucking moisture north. The good news is if it develop's it will probably go north of Trini if not more rain for you 4-5 days from now.. the bad news is it may come straight here to the Virgins...
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Quoting txag91met:


SE of Jamaica...very broad low beginning...still long ways to go.

If you are talking about 75.0W 17.4N, then yes I agree.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting CybrTeddy:


Out of curiosity, how do you know?


He is a legit Met if you want to know his credentials.
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Quoting Dakster:


I haven't read the entire ruling/opinion so I don't have my own opinion yet.

But isn't this why we have a court of appeals and a supreme court? If one "side" feels the law wasn't applied correctly then there is a higher court to go to. It is also one of the reasons why the higher courts are a panel and not heard by a single person.


And you can rest assured that the US Attorney will take this to the 5th Circuit and see what they think about it.

Mike
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1439. Drakoen
Quoting txag91met:


SE of Jamaica...very broad low beginning...still long ways to go.



Yup. Mentioned it earlier when I was trying to figure out why the NHC lowered its chances.

Member Since: October 28, 2006 Posts: 57 Comments: 29886
Just letting everyone know how easily tracks can change even after the Hurricane Center starts issuing advisories on a system.
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Quoting txag91met:


SE of Jamaica...very broad low beginning...still long ways to go.



Out of curiosity, how do you know?
Member Since: July 8, 2005 Posts: 259 Comments: 23568
1436. NRAamy
PT is killin' me....
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Quoting Clearwater1:
Given the nearly stationary high in the Atlantic, near 31, per earlier nhc post, what leads you to beleive the models will shift right?


a trough. A trough can erode the high and cause the storm to take a more easterly path which is what the GFS and HWRF are seeing. Granted the ECMWF is better at handling troughs so we stillhave to see if the trend will be more east
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Quoting txag91met:


SE of Jamaica...very broad low beginning...still long ways to go.





if that right then 93L is not going too MX
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Quoting Floodman:


SHHHHHHH...



THIS IS STORMTROP FROM MY BASEMENT WEATHER OFFICE IN MY MOMS HOUSE... STORMTROP.


or stormcat from my basement weather office in my grandmas house... stormcat.
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Quoting ElConando:


I noticed around the time you posted but I'm not sure what the coordinates would be exactly.


SE of Jamaica...very broad low beginning...still long ways to go.

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Quoting txag91met:
Broad surface low beginning to form....

Finally.

And so it begins.


I noticed around the time you posted but I'm not sure what the coordinates would be exactly.
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1428. Dakster
Quoting NOLALawyer:


Have you ever practiced in his court? I have and continue to do so. Even the most seasoned attorneys fear and respect Judge Feldman because he is, quite simply,a brilliant and intimidating jurist. You know nothing about him, yet you attempt to put some kind of financially motivated spin on his ruling. He is also a conservative and not typically aligned with the Plaintiff's bar. So, you can rest assured that his ruling is soundly based in the law, well written, and not motivated by his own personal greed. He is a rare judge in the EDLA, one that actually applies the law correctly.

Mike


I haven't read the entire ruling/opinion so I don't have my own opinion yet.

But isn't this why we have a court of appeals and a supreme court? If one "side" feels the law wasn't applied correctly then there is a higher court to go to. It is also one of the reasons why the higher courts are a panel and not heard by a single person.
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1427. hydrus
Quoting CybrTeddy:


I don't believe that those are two separate systems, no model support for 93L splitting in two.
Actually there is.Link
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Quoting txag91met:
Broad surface low beginning to form....

Finally.

And so it begins.


Very broad though, will take a while to fully tighten up.
Member Since: July 8, 2005 Posts: 259 Comments: 23568
Quoting NRAamy:
yo Jerry....

:)


Howdy, darlin'!
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Quoting RobertM320:


And that's easy to say in hindsight. Would you have guaranteed that on September 21, 2001? I doubt it. And its been two months and I haven't seen any other rigs explode either. Again, you punish everyone for one companies mistake. Heck, if you want, shut all of BP's rigs down.

Let's try this for example: If three different tourists got murdered on three different Florida beaches in one week, would you shut down all the beaches throughout the entire state until the murderers were caught? .... I didn't think so.


There are not other rigs exploding (yet), but there are other rigs with serious safety issues, including one (ocean saratoga) that is leaking a 10 mile long slick into the gulf. Corners have been cut, and until we find out where and when, drilling is not safe.

And other companies have been called out for their safety practices also, including not having a solid plan in place as to what to do in an oil spill. Those guys also have walruses listed as wildlife in the Gulf... sounds like they really have their stuff together.

And your example is apples to oranges. You wouldn't shut down the beach, as the beach didn't cause the murder.
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1421. xcool


60hr
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Quoting txag91met:
Broad surface low beginning to form....

Finally.

And so it begins.
Coordinates?
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting txag91met:
Broad surface low beginning to form....

Finally.

And so it begins.



where???
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Broad surface low beginning to form....

Finally.

And so it begins.
Member Since: Posts: Comments:
1417. Drakoen
Looks like the GFS is finally on board though it is still conservative.
Member Since: October 28, 2006 Posts: 57 Comments: 29886
Quoting NRAamy:
where's STORMTOP?


SHHHHHHH...
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Quoting Jeff9641:
GFS seems to following the HWRF model. Models will shift to the right later. Notice the trough building in from the north. Shear will increase to 30knts in the western gulf later this weekend.
Given the nearly stationary high in the Atlantic, near 31, per earlier nhc post, what leads you to beleive the models will shift right?
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Quoting nrtiwlnvragn:
Forecast: [-] soon to turn to Ignore User


?????????????
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1412. unf97
Quoting DDR:
Good evening
Rain/floods here in Trinidad today,Is anyone else watching that wave in the Central Atlantic?



It is being watched. Like ex-92L, that wave is far to the south. If it can gain latitude in a few days, it may indeed be the next AOI, or possibly our next invest.
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Quoting MrMarcus:


I stand corrected. Waiting for the Atlantic season to get started. 91, 92 & 93L were/are nothing more than a few clouds bringing a little rain. If that's your idea of a season, it's gonna be pretty boring. Not that boring (like last year) is a bad thing ;-)


92L and 93L have been bad signs for the season. 92L almost become a tropical depression.. that far east so early in the season has almost never happened. 93L looks like a disturbance one would see in late July not mid to late June.
Member Since: July 8, 2005 Posts: 259 Comments: 23568
Forecast: [-] soon to turn to Ignore User
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Quoting StSimonsIslandGAGuy:


I didn't taint his ruling. He did it himself by ruling in favor of companies he had had previous interests in, and in TransOcean which he still had $15,000 in stock holdings in according to the most recent disclosure filing giving assets from 2 years ago.

Furthermore, it's a free country--how dare you issue orders telling me what I may or may not say.


Have you ever practiced in his court? I have and continue to do so. Even the most seasoned attorneys fear and respect Judge Feldman because he is, quite simply,a brilliant and intimidating jurist. You know nothing about him, yet you attempt to put some kind of financially motivated spin on his ruling. He is also a conservative and not typically aligned with the Plaintiff's bar. So, you can rest assured that his ruling is soundly based in the law, well written, and not motivated by his own personal greed. He is a rare judge in the EDLA, one that actually applies the law correctly.

Trust me, petroleum stocks in his portfolio or not, he would be my pick every time on this case. With him, at least I know the ruling is based in the law.

Mike
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Quoting StormW:


ADT


Many thanks StormW,

I knew how its works ADT, but i dont understand why offical report talk about 85-90 kts on Celia and ADT never give more than 75 kts, in some hurricanes was more than official and others less , thats why im confused.
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Quoting MiamiHurricanes09:
This seems to be what is going on.



I don't believe that those are two separate systems, no model support for 93L splitting in two.
Member Since: July 8, 2005 Posts: 259 Comments: 23568
Quoting MiamiHurricanes09:
Looks like you haven't been paying any attention.


I stand corrected. Waiting for the Atlantic season to get started. 91, 92 & 93L were/are nothing more than a few clouds bringing a little rain. If that's your idea of a season, it's gonna be pretty boring. Not that boring (like last year) is a bad thing ;-)
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1404. xcool



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1402. xcool
about time GFS
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1401. DDR
Good evening
Rain/floods here in Trinidad today,Is anyone else watching that wave in the Central Atlantic?
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AMZ088-230330-
SYNOPSIS FOR THE SW N ATLC INCLUDING THE BAHAMAS
530 PM EDT TUE JUN 22 2010
.SYNOPSIS...A RIDGE WILL REMAIN NEARLY STATIONARY ALONG 31N
TONIGHT THROUGH SUN. A TROPICAL WAVE IN THE CENTRAL CARIBBEAN
EXTENDING N TO NEAR 22N73W WILL MOVE TO THE W-NW THROUGH THE
STRAITS OF FLORIDA THU AND THU NIGHT. EXPECT VERY HEAVY RAINFALL
ASSOCIATED WITH THE WAVE
. A TIGHT PRES GRADIENT BETWEEN THE
RIDGE AND WAVE WILL BE IN PLACE S OF 26N UNTIL FRI.
$$
FORECASTER LEWITSKY


Two things here... First, Lewitsky must be talking about the wave axis itself, not the CoC of a potential tropical cyclone.

Secondly... We see Lewitsky is working for the TPC, where is Bill Clinton??? LOL... oh wait, that was Lewinsky, duh.
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Quoting CybrTeddy:


Is this recent?


No, 8:45PM yesterday.
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1397. NRAamy
yo Jerry....

:)
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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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