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

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

Share this Blog
5
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 2046 - 1996

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75Blog Index

2044. IKE
Interesting that both the GFDL and HWRF thread the needle between the Yucatan peninsula and Cuba....GFDL winds up at 90.8W and the HWRF at 88.4W as they approach the northern GOM coast.

Going through the Yucatan channel.....



Member Since: June 9, 2005 Posts: 23 Comments: 37860
2043. help4u
Storm w do you think 93l will hit texas?
Member Since: Posts: Comments:
This could be a long record-breaking season. Get your rest.
Member Since: Posts: Comments:
Quoting StormW:


I agree. Be glad when this thing finally pops...be able to forecast steering much better.

Aint that the truth. It seems to be finally coming along tho.
Member Since: Posts: Comments:
2038. USCGLT
Hey Tom (StormW) Looks like it could be a busy season...I gave in and moved 15 miles inland...Katrina and Gustav was enough for me!!

Member Since: Posts: Comments:
Quoting sporteguy03:
What is a "normal" hurricane season anyways? If you get hit by a major hurricane are you going to say I got hit during a "normal" season or I got hit by ______ hurricane. To me numbers are for record books, hurricanes are things you put in your photo book that you always remember.
I agree with you 100%.... That statement is so True....

Taco :o)
Member Since: Posts: Comments:
I wonder if the blob around 68W is robbing the center of its moisture from the east?
Member Since: Posts: Comments:
Quoting StormW:


Yeah...cept I prefer the middle of the ATCF suite right now as far as initial track, based on all the new goings on.

Well depending on landfall, that could be worse for me. Would put me on the east side. But yea lets take it day by day.
Member Since: Posts: Comments:
2033. 900MB
Quoting MiamiHurricanes09:
But there is a surface low to initialize on now, so models aren't useless.


Let's just say an organized surface low, td status or better is far more predictable. Models have this spread so wide that they matter little at this point.
Member Since: Posts: Comments:
2030. leo305
central atlantic low beginning to develop some convection, and its rapping itself with the ITCZ moisture
Member Since: Posts: Comments:
Strong Tropical Wave in the Caribbean
Jun 22, 2010 5:51 PM


We continue to monitor the movement of a strong tropical wave in the central Caribbean between 70 and 75 west longitude and mostly south of 22 north latitude. The short term concern will be for heavy rain and gusty winds over Puerto Rico, Hispaniola and eventually over parts of Cuba and Jamaica. This heavy rainfall could cause flooding and in the higher terrain life threatening mudslides. The disorganized system will move west northwest for the next few days. We believe a low level circulation will gradually form during Thursday and Friday south of the main thunderstorm area near Jamaica. This feature will track into the northwest Caribbean on Saturday then move over the Yucatan peninsula during Sunday. A west east oriented upper level ridge located from Texas into the southeast U.S. will be in place north of this system into early next week creating easterly steering winds across the Gulf of Mexico into Texas . If this Atlantic ridge weakens over Texas and the western Gulf of Mexico the system will track on a more northwesterly course. This could take the system into the western Gulf of Mexico and on a course towards Texas or Louisiana next week. If the Atlantic ridge holds strong across Texas and the deep southern United States the system will track into the southwest Gulf of Mexico and into Mexico next week. As far as strengthening some computer information suggests this feature will become a well organized tropical feature by this weekend while other computer information keeps the system weak and disorganized. Until the system becomes better defined initially we cannot be confident about future development.

A well defined tropical wave near 35 west longitude mostly south of 18 north latitude. This tropical wave shows some rotation in the cloud motion but the feature is also partially wrapped up with dry African dust. So, development is not expected any time soon. Other tropical waves along 62 west and roughly along 85 west remain weak and disorganized.

By AccuWeather Expert Senior Meteorologist Dan Kottlowski
Member Since: Posts: Comments:
Quoting sporteguy03:
What is a "normal" hurricane season anyways? If you get hit by a major hurricane are you going to say I got hit during a "normal" season or I got hit by ______ hurricane. To me numbers are for record books, hurricanes are things you put in your photo book that you always remember.

Amen!
Member Since: Posts: Comments:
Quoting StormW:
GFDL:

img src="Photobucket" alt="" />

ATCF MODEL SUITE

img src="Photobucket" alt="" />

Evening Storm. Definately dont like that GFDL run. Reminds me of Gustav.
Member Since: Posts: Comments:
Hmmm...the more I look at the low clouds on the visible, the more I see a LLC forming at 15N, 76.5W.....
Member Since: Posts: Comments:
2023. IKE
Not surprised by the latest TWO.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
2022. mchuter
Quoting hcubed:


The ants in my backyard are starting to build in new places - and they're putting the mounds on stilts.

Is that a bad sign?


Mine too here in Slidell.....looks like a mini grand isle.......
Member Since: Posts: Comments:
What is a "normal" hurricane season anyways? If you get hit by a major hurricane are you going to say I got hit during a "normal" season or I got hit by ______ hurricane. To me numbers are for record books, hurricanes are things you put in your photo book that you always remember.
Member Since: Posts: Comments:
2020. DehSoBe
why im i having trouble quoting other people?
Member Since: Posts: Comments:
Quoting CaicosRetiredSailor:

Looks much better then last nights pass.
Member Since: Posts: Comments:
Thunderstorm have started to fire up where NHC is giving the center
Member Since: Posts: Comments:



after posting this I am wondering if it is from yesterday ... not sure.
Member Since: Posts: Comments:
Quoting Baltimorebirds:
I hate cake.

You like cookie cake? Thats still considered cake LOL.
Member Since: Posts: Comments:
whats get this show on the road
Member Since: May 21, 2006 Posts: 5091 Comments: 115439
Quoting AllStar17:
The EPAC is about to spit out another. If all of this EPAC action was in the Atlantic, this blog would explode.

Expect Celia and Five-E at 11 for the EPAC.
Did you get my email?
Member Since: Posts: Comments:
2010. 900MB
Quoting DehSoBe:
you are right, but i think most people that hear 20% does not know that is only for a 48 hr period. Once the storm is on top of them they up the percentage... a little too late


You are correct! The NHC should have a 48 hour number and an overall number.
Member Since: Posts: Comments:
2009. hcubed
Quoting CosmicEvents:

Back in 2005 we first learned of a possible connection between ants and approaching cyclones. In order to fit the criteria what you see must be:
NEW ANT HILLS.large, IN NEW SPOTS.
.
.
In 2005, we had reports from the New Orleans area 10 days prior to Katrina of beaucoup ant mounds on soccer fields, and other areas that normally didn't have large ant mounds.


The ants in my backyard are starting to build in new places - and they're putting the mounds on stilts.

Is that a bad sign?
Member Since: Posts: Comments:
Quoting 900MB:


Until this organizes I think all models are useless.
But there is a surface low to initialize on now, so models aren't useless.
Member Since: Posts: Comments:
Quoting spathy:
We here in SW Florida had our strongest East to West flow of the season today.
Almost completely shut down the sea breeze pattern.
Did I read earlier that this strong flow may weaken a little later?
As 93? gets further West.
.
Does popcorn go with pizza?

You better believe it!! Like icing on cake!
Member Since: Posts: Comments:
Quoting GeoffreyWPB:
At its current status, the NHC is totally correct with the 48 hour forecast.
In the next 48 hours totally agree with the numbers they are giving too.
Member Since: Posts: Comments:
2004. 900MB
Quoting Dropsonde:
The GFDL run doesn't really "get it together" until it's almost at Yucatan. It's a broad and/or weak vortex until then. Considering how sloppy this thing still is, I wouldn't doubt that. The models may or may not be out to lunch with the ultimate track and landfall site, but the general idea of it taking a while to pull its circulation together and spin down to the surface seems on target.


Until this organizes I think all models are useless.
Member Since: Posts: Comments:
Quoting homelesswanderer:


I agree 100%. Under-hype is more dangerous than the other way around. We had local media telling people not to evacuate from Ike on the morning of the 11th. While water was already cutting off some roads. Ridiculous!!!

Alot happened like that with Katrina too. I bought a documentary recently by Spike Lee on Katrina... really hit home. So many people just werent prepared and didnt take the storm seriously. Therefore, I am ALL about the hype. Whatever it takes to wake people up!!
Member Since: Posts: Comments:
ROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUN 22 2010

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2230 UTC...

...SPECIAL FEATURES...

A STRONG TROPICAL WAVE IS MOVING THROUGH THE CENTRAL CARIBBEAN
EXTENDING FROM TURKS AND CAICOS NEAR 21N73W ACROSS THE WINDWARD
PASSAGE TO THE COAST OF COLOMBIA NEAR 11N74W MOVING W NEAR 12
KT. THE WAVE IS ACCOMPANIED BY A LARGE AREA OF DEEP LAYER
MOISTURE THAT COVERS THE ENTIRE CENTRAL AND ERN HALF OF THE
CARIBBEAN EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. BROAD LOW
TO MID-LEVEL CYCLONIC FLOW IS ABOUT THE WAVE. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 14N-19N BETWEEN 66W-72W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N-21N
BETWEEN 72W-78W. THIS LARGE AREA OF ACTIVITY IS EXPECTED TO
BRING 4-7 INCHES OF RAIN TO HISPANIOLA. HEAVY RAINFALL IS ALSO
POSSIBLE ACROSS PUERTO RICO.
Member Since: May 21, 2006 Posts: 5091 Comments: 115439
2000. DehSoBe
True but sad
Member Since: Posts: Comments:
Quoting alaina1085:


Well I personally rather the over hype and to be let down then the under hype and be caught totally off guard. You have to respect the fact that these mets are doing the best that they can with very little tools. So until I have been 100% in there shoes, Im just grateful with the info available. Just my oppinion.


I agree 100%. Under-hype is more dangerous than the other way around. We had local media telling people not to evacuate from Ike on the morning of the 11th. While water was already cutting off some roads. Ridiculous!!!
Member Since: August 15, 2008 Posts: 10 Comments: 3665

Viewing: 2046 - 1996

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75Blog Index

Top of Page

About

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

Local Weather

Overcast
30 °F
Overcast