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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2095. IKE
Quoting CyclonicVoyage:


TCVN is nearly exactly the same as the GFDL in terms of track.


That's the main one the NHC uses. Interesting.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting alaina1085:

I do believe spike lee is biased. But I still bought it. There are always 2 sides to every story. I pull a little bit from here and little from there. I dont blame bush, I love president bush. I just look at all whats available out there then make my oppinions. Either way, what happened was sad... tragic!
agreed, but I bet none of those people stay next time! I would walk if I had to. Back to 93L
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2093. Patrap
Quoting JFLORIDA:
Oh thats marvelous Pat.


Welcome to 2010
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2091. Drakoen
Not really suprising to see the shifts in the GFDL and HWRF. Getting a system from the Caribbean into Texas this time of year is a difficult feat.
Member Since: October 28, 2006 Posts: 57 Comments: 30492
Quoting weatherwatcher12:
22/2345 UTC 17.4N 71.8W TOO WEAK 93L
From the SSD


ssd has the wrong center
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Quoting 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.....





TCVN is nearly exactly the same as the GFDL in terms of track.
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maybe the 2 spins are what the cmc is picking up on it shows two storms
2086. IKE
Quoting CanesfanatUT:


Thanks! So it doesn't see a TS till Friday, it looks like.


That looks about right. One other thing I noticed on the GFDL. At the end of the run it starts a turn to the east of due north. Would slam it right into SE LA.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
22/2345 UTC 17.4N 71.8W TOO WEAK 93L
From the SSD
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Quoting robie1conobie:
exactly. Spike Lee is an idiot! Everyone just wanted to blame Bush for their stupid decision to stay.

I do believe spike lee is biased. But I still bought it. There are always 2 sides to every story. I pull a little bit from here and little from there. I dont blame bush, I love president bush. I just look at all whats available out there then make my oppinions. Either way, what happened was sad... tragic!
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2083. Patrap
Floater - RGB Color Infrared Loop
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Quoting stormpetrol:
I see 2 spins with 93L one around 15N/74W which I think is LLC and another around 17N/72W which I believe to be the MLC, do they consolidate or does one become the dominant center that is the question in my opinion.


I see my thoughts on the COC/LLC were correct earlier!
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poor BP
Member Since: May 21, 2006 Posts: 5091 Comments: 115125
2079. Patrap
Bada Bing, bada BOOM

CMC 12Z
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Yea this is a disaster waitng to happen but i am glad that people are taking this serious and with each model run it looks bad from nola to florida pandhandle
Quoting StormW:
CATL IR2 LOOP


What do you think of the 9N 39W area?
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Quoting IKE:
Link


Thanks! So it doesn't see a TS till Friday, it looks like.
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Quoting CybrTeddy:


Looks like ASCATs going to miss the low pressure area, but it does appear that this is organizing.




and fast has well
Member Since: May 21, 2006 Posts: 5091 Comments: 115125
Quoting sarahjola:
nothing like that happened for katrina. all the media kept telling people was how bad it was going to be and to leave. i was there. everyone knew how bad katrina was going to be, just some people would rather wait for someone to take care of them rather than do it themselves. everyone in Louisiana, Mississippi, and Alabama knew what was going to happen. it really bothers me when people suggest that no one was told of the dangers. we were told over and over. did spike lee mention how people were pulling up to the superdome in brand new cars filled with kids, with no food or water? did that documentary mention how the media was out there asking people why they didn't have food for their kids, and why they weren't just leaving instead of going to the superdome. i remember people telling the media who were warning them that the superdome was not a shelter, that if we have to we will get food from the concession stands. what? they have no food at the concession stands unless there is an event there. people chose to ignore the warnings and did exactly what they were told not to do and then wanted to blame everyone but themselves for the situation they found themselves in. if your to ignorant to understand get out or die then that your problem. personal responsibility!!!!
exactly. Spike Lee is an idiot! Everyone just wanted to blame Bush for their stupid decision to stay.
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Quoting Drakoen:


Looks like ASCATs going to miss the low pressure area, but it does appear that this is organizing.
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Quoting sarahjola:
nothing like that happened for katrina. all the media kept telling people was how bad it was going to be and to leave. i was there. everyone knew how bad katrina was going to be, just some people would rather wait for someone to take care of them rather than do it themselves. everyone in Louisiana, Mississippi, and Alabama knew what was going to happen. it really bothers me when people suggest that no one was told of the dangers. we were told over and over. did spike lee mention how people were pulling up to the superdome in brand new cars filled with kids, with no food or water? did that documentary mention how the media was out there asking people why they didn't have food for their kids, and why they weren't just leaving instead of going to the superdome. i remember people telling the media who were warning them that the superdome was not a shelter, that if we have to we will get food from the concession stands. what? they have no food at the concession stands unless there is an event there. people chose to ignore the warnings and did exactly what they were told not to do and then wanted to blame everyone but themselves for the situation they found themselves in. if your to ignorant to understand get out or die then that your problem. personal responsibility!!!!

Hey I agree with you there too! But there are also alot of lower class poor people who just didnt have the funds or the money to make it out. So they stayed or sheltered at the superdome. Then fema never really came through and water and food ran out. It took 5 days for fema to get water and food to these people. There was alot of miscommunication.
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evening everyone...just got off work from cleaning the tar off the beach in gulf shores today...all the talk today was about this possible future storm...this would be the worst case situation for sure....just looked at the all the models and it does not look good at all...and apparentaly the coast guard are seeing this too...news was saying how they are needing to get more skimmers out before the storm comes and how to make sure nothing else gets damaged during a cane....going to be 1 of the most interesting years to say the least and this is only the start....
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2068. IKE
Quoting CanesfanatUT:
Can someone post a link to the GFDL? I can't find it here or trying Google.

Thanks.
Link
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Can someone post a link to the GFDL? I can't find it here or trying Google.

Thanks.
Member Since: Posts: Comments:
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?



yea last week i saw black birds in a group da last time i saw dat was right before katrina so you might be on to something
2062. IKE
Quoting btwntx08:
u miss the action earlier ike and actually those two model have it going toward patrap


GFDL does....HWRF aims it further east.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
4424 comments and 39 entries posted by all members in the last 24 hours.

You have posted 5074 entries in your own blog.

You have posted 43508 comments in all blogs.


ohs going to make 50,000 commets be for 93L hit the gulf coast this blog is going too be like a made hous i made about 90 too 100 commets i bet in this blog today
Member Since: May 21, 2006 Posts: 5091 Comments: 115125
2060. Drakoen
Member Since: October 28, 2006 Posts: 57 Comments: 30492
2058. Kibkaos
Quoting StormW:
GFDL:

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

ATCF MODEL SUITE

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

This is going to be a busy few days if these models hold true. In your opinion what are some of the major things that may affect the models drastically in the next 24 hours?
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Quoting btwntx08:

anticyclone right over it it seems

Yup!
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Quoting alaina1085:

If these pan out I will seriously start to believe these storms hsve eyes and a brain!


She mad, and makin up for last season!




lol
Member Since: May 21, 2006 Posts: 5091 Comments: 115125
2054. IKE
Quoting StormW:
Anybody else get the feeling Mother Nature ain't waitin' for July (or AUG/SEP)?


Looks that a way.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting alaina1085:

Alot happened like that with Katrina too. I bought a documentary recently by Spike Lee on Katrina... really hit home. So many people just weren't prepared and didn't take the storm seriously. Therefore, I am ALL about the hype. Whatever it takes to wake people up!!
nothing like that happened for katrina. all the media kept telling people was how bad it was going to be and to leave. i was there. everyone knew how bad katrina was going to be, just some people would rather wait for someone to take care of them rather than do it themselves. everyone in Louisiana, Mississippi, and Alabama knew what was going to happen. it really bothers me when people suggest that no one was told of the dangers. we were told over and over. did spike lee mention how people were pulling up to the superdome in brand new cars filled with kids, with no food or water? did that documentary mention how the media was out there asking people why they didn't have food for their kids, and why they weren't just leaving instead of going to the superdome. i remember people telling the media who were warning them that the superdome was not a shelter, that if we have to we will get food from the concession stands. what? they have no food at the concession stands unless there is an event there. people chose to ignore the warnings and did exactly what they were told not to do and then wanted to blame everyone but themselves for the situation they found themselves in. if your to ignorant to understand get out or die then that your problem. personal responsibility!!!!
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Quoting StormW:
Anybody else get the feeling Mother Nature ain't waitin' for July (or AUG/SEP)?
With all due respect Storm I felt that way 2 weeks ago when we had 92L....

Taco :o)
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Quoting 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.

Going through the Yucatan channel.....




If these pan out I will seriously start to believe these storms hsve eyes and a brain!

Quoting StormW:
Anybody else get the feeling Mother Nature ain't waitin' for July (or AUG/SEP)?

She mad, and makin up for last season!
Member Since: Posts: Comments:
Quoting 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.....






has a 956md low
Member Since: May 21, 2006 Posts: 5091 Comments: 115125
gfdl track-similar to camille- once it makes the turn in the yucatan, then it's off to the races. that front coming down thru the middle usa is a polar front.in two days the models will be able to pinpoint landing easily. watches out at 48 hrs-like fri daytime.the gfs may be showing the front picking up the tw behind this system.
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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.