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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This wave is getting more organized by the hour. I wouldn't be surprised if this isn't a TD before the day is out. Will be interesting to see if it can keep its convection going during the day. Looks a strong line of storms speeding across southern Haiti may give it an extra boost of energy today.
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Brazil floods kill 41 as 1000 missing

* From: AFP
* June 23, 2010 8:16PM


RAGING floods in northeastern Brazil have killed at least 41 people and left as many as 1000 missing, while firefighters described entire towns being wiped off the map.

Dramatic television pictures showed survivors scrambling to rooftops to avoid being swept away, clinging desperately to lines of rope as rescuers in helicopters rushed to pluck them from the muddy floodwaters.

The death toll looked set to rise with more heavy rain forecast and the authorities giving estimates of the missing ranging from several hundred to 1000.

"Up until the early afternoon we had 26 confirmed dead in Alagoas and more than 1000 people missing," the governor of the poor coastal state Teotonio Vilela Filho told government news wire Agencia Brasil.

"But we are worried because bodies are starting to appear on the beaches and the rivers."
President Luiz Inacio Lula da Silva announced late yesterday that he would be back to overfly the area on Thursday, as Defense Minister Nelson Jobim has done, the official news agency Agencia Brasil reported.

Officials later raised the toll in Alagoas to 29, while a civil defence officials said another 12 fatalities were confirmed in the larger neighbouring state of Pernambuco.

Almost 100,000 people in the two states were left without a home or forced to evacuate, while some towns were completely cut off as powerful torrents collapsed bridges and swamped roads and railway lines, officials said.

Rooftops and church bell towers were the only structures visible above massive brown expanses of floodwater that only looked set to rise in the coming days.

A firefighters' spokesman told AFP entire towns had been "wiped off the map" after the Mundau river burst its banks in the town of Uniao dos Palmares in Alagoas.

In the separate town of Palmares in the neighbouring state of Pernambuco, a woman who lost her home sobbed as she told Globonews television: "It destroyed our city. It destroyed everything."

Jose Mariano, whose house in nearby Cachanga was waterlogged, said: "It was really tough here. We had a refrigerator and an armoire at my brother's house for safe keeping and the water came in and just kept rising."

Five Air Force helicopters ferried aid to those stranded by the flooding, while a military plane also delivered some 14 tonnes of donated food, medicine, drinking water and mattresses.

Lula held a crisis cabinet meeting that included ministers and the governors of the affected states.

Afterwards, officials announced $US55 million ($A63 million) in emergency aid, half of which had already been delivered to the state governments.

Governor Padilha said the priority was to get emergency drinking water and food to the flooded areas, and restore electricity.

In April, flooding and landslides triggered by torrential rain killed at least 229 people in the Rio de Janeiro area.
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Quoting RecordSeason:
Why is it that the people who make the loops for ALL of these websites are incompetent? They are always late publishing them, and they put the frames in the wrong order half the time. It's ridiculous they get payed to do this.


I take it you're in management?
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Hello Pat, This weather system blowing over us has brought the oil smell back down here, you noticed it uptown? I think it is worse than before :(
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3691. Patrap
Quoting StormW:


Good info Pat!

But I like calling..LOL!!


Ya gotta keep up with the Kids techno stuff Chief.

Phones are so passe ya know.

I got a text from portlight last 15
Member Since: July 3, 2005 Posts: 428 Comments: 129796
Quoting wunderkidcayman:
no the hunters flight are not canceled but reschedule.


canceled for today

6 of one and half dozen of the other, basically the same thing lol
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Sorry, Keesler it is....
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Hello everybody!!!!!,I'm wondering why the models or the official track has the center of circulation or the future center of circulation East and South.Looking at the satellite presentation in my opinion the center is trying to relocate just south of Haiti,much father north??,any comments about this observation.Thanks!
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no the hunters flight are not canceled but reschedule.
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3684. 34chip
I live on Emmma St in Key West in the Condos
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So, how is it that there's NOT a COC SW of PR?

http://www.ssd.noaa.gov/goes/flt/t1/loop-rb.html

There also looks to be a smaller one that's fading SW of Haiti - but the one SW of PR seems to be sapping it's energy. Does anyone have a link w/isobars?
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3682. will45
Quoting StormW:


If I'm correct, when they do go, the tasking should go to MacDill, right?

I talked to Randy yesterday who flys with HH and he is saying Keesler
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3679. jpsb
Quoting WindynEYW:
" our drainage is evaporation

We must be neighbors!
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Quoting StormW:


If I'm correct, when they do go, the tasking should go to MacDill, right?


Keesler's a little far off but they could run out of there if needed. MacDill would be my guess.
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3677. Patrap
One can recieve NHC Update via E-mail..and Twitter of you sign up.

Never miss a TWO or HH flight schedule.
Member Since: July 3, 2005 Posts: 428 Comments: 129796
the anticyclone is moving out ahead of 93L, that is not going to help it develop
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Quoting wunderkidcayman:
I am very sorry they have changed the flight plan the flight plan as follows

000
NOUS42 KNHC 231345
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
0945 AM EDT WED 23 JUNE 2010
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 24/1100Z TO 25/1100Z JUNE 2010
TCPOD NUMBER.....10-023

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (SOUTHWEST OF JAMAICA)
FLIGHT ONE - TEAL 70
A. 24/1800Z
B. AFXXX 01AAA INVEST
C. 24/1330Z
D. 16.5N 80.0W
E. 24/1700Z TO 24/2100Z
F. SFC TO 10,000 FT

FLIGHT TWO - TEAL 71
A. 25/0600Z
B. AFXXX 0201A CYCLONE
C. 25/0200Z
D. 17.0N 81.0W
E. 25/0400Z TO 25/0830Z
F. SFC TO 10,000 FT

2. SUCCEEDING DAY OUTLOOK: CONTINUE 12 HRLY
FIXES IF SYSTEM REMAINS A THREAT.
3. REMARKS: TASKING FOR 23/1800Z AND 24/0600Z
CANCELED BY NHC AT 23/0930Z.

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
JWP




so what does that mean?? I don't know what all that means? Is it canceled?
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ok all off to watch usa beat the pants of algeria back later play nice
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Quoting nrtiwlnvragn:


MacDill is for NOAA, operational tasking is usually USAF.


And typically flies out of Biloxi, MS.
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3670. IKE
Quoting btwntx08:

???????????????


Where do you live? Let me guess...Texas?
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3669. bappit
3654

Ok. I got tired of waiting, so I called..spoke with John of CARCAH.

Thanks for the info.
Member Since: May 18, 2006 Posts: 10 Comments: 6156
Quoting StormW:


If I'm correct, when they do go, the tasking should go to MacDill, right?


MacDill is for NOAA, operational tasking is usually USAF.
Member Since: September 23, 2005 Posts: 15 Comments: 11341
3667. Walshy
I hear they really want a recon in 93L before it goes into the GOM. Still plenty of time to wait and watch.
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3666. 34chip
I live in Key West also.I know about flooding. lol!!! One wrong move then we are under the gun. lol
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Quoting Jeff9641:
If I was in Key West I would watch this the next couple of days. As a storm moving off the eastern tip of Cuba will have big impacts on Key West.
I am part of the eoc/ems/drt team we have had preplan hurricane meetings in the past few weeks and are always watching the weather. we dont rely on fema to take care of us here, we take care of our own
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3664. aquak9
bjdsrq- I hope you are right. Figured they'd high-tail it outta there at the first opportunity.
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Quoting StormW:
Just got off the phone with the NHC, CARCAH...Recon HAS been canceled today and is on for tomorrow.


SUCCEEDING DAY OUTLOOK: CONTINUE 12 HRLY
FIXES IF SYSTEM REMAINS A THREAT.
3. REMARKS: TASKING FOR 23/1800Z AND 24/0600Z
CANCELED BY NHC AT 23/0930Z


This mornings satellite imagery shows an improving look to the overall appearance of the area in the upper levels but boy convection still remains ill defined. There is some shear there 15-20kts but nothing to prohibitive. Thought i'd mention the 12z UK is doing much of anything with this. Long way from being a tc.
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Shear map gyre just tightened up again.
Click plus and minus three hour.
Link
Off to hard labor.
Have scored and primed, now must paint the carport. therefore bravely i go. sheesh.
Member Since: July 11, 2006 Posts: 14 Comments: 11423
anyone have a link with isobars on it for 93L, it looks like the low is reforming SW from where it is now. It also seems to be spinning now. Any comments?
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3659. gator23
Quoting btwntx08:

Quoting gator23:

you are correct Jeff, not to mention that the BIG BEND of Florida isnt safe either. He belives the models are worth a lick, the models are crap without a well defined LLC
yes i do i believe the models maybe right

So then, your not confused?
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Quoting Patrap:
The Models reflect what may occur as to the envelopes future downstream, To say there is no LLC is moot as the energy is there .

Or the invest wouldnt be under scrutiny.

Relax..

Have a Dr. Peppa.

The My yard,my State things is as stale as week old french toast.

Saying there IS an LLC is just wrong and implies a far greater degree of development than exists.

Once you have a solid COC development can be extremely rapid < 24 hours to a hurricane.
That is why saying it does not exist is NOT MOOT! If there was a COC or even LCC on either are of convection that are S SE of PR and the VI's my course of action would be VERY different. I would be on my boat to a hurricane hole not posting on the board.

Yes the energy is there but the MCV's that everyone is looking at and calling centers of circulation are not.
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3655. hercj
Quoting StormW:
Just got off the phone with the NHC, CARCAH...Recon HAS been canceled today and is on for tomorrow.

I thought they would do that. Nothing really to look at today.
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Quoting smmcdavid:


Thanks! I'm trying to keep up... but I'm having to do a lot of clean up today. Sick kids are no fun. :(


Poor you:(
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3652. bjdsrq
Quoting aquak9:


Wrong. Storm in Gulf means all relief-well work stops. Suction stops. ROV's leave. And it goes back to spewing like crazy.

Whatever gets dispersed at the surface will be replaced ten-fold at the leak.


They stated that won't leave for any TS storm. It would have to be bad. I guess we might find out what that threshold of pain is before too long. The ROV equipment and crews are used to being deployed in the north sea, where wind and wave conditions are worse than a TS about 6 months out of the year.
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Quoting 34chip:
At the moment Key West and the Florida Keys sure watch this system!
"WE" always watch every storm every season even a mild tropical storm causes flooding here, our drainage is evaporation
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3650. Walshy
Quoting StormW:


From who?



Received it from:

nhcwebmaster@noaa.gov.
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Quoting Jeff9641:
Mid level circulation is very evident S of Haiti and we now may have a surface reflection. Does anybody have any maps to confirm this. Models need to be moved to 72W. This is why we need a recon.

I'm not calling them wussies.
Member Since: July 11, 2006 Posts: 14 Comments: 11423
3647. Patrap
Floater - RGB Color Infrared Loop
Member Since: July 3, 2005 Posts: 428 Comments: 129796

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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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