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: 846 - 796

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

That red is coming straight for me Pat
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
So have there been any ripcasters yet since 93L curiously went yellow?


Of course.
Member Since: Posts: Comments:
Quoting help4u:
Golf, anyone?
It appears it will go in the southern gulf.Away from the oil spill.
Member Since: Posts: Comments:
Shear is 10-20 knots over the system versus the 5-10 knots we saw yesterday. That could be why although it doesn't appear to be hindering the system.
Member Since: October 28, 2006 Posts: 57 Comments: 30615
Quoting Floodman:


And if there's another BP style blowout? What do we do with two?


I have no intention of bringing politics into this arena. However, I feel that a six month blanket moratorium was not the best solution. I certainly do not mind discussing the issue in more detail with you via WUmail if you desire.
Member Since: Posts: Comments:
Quoting Baltimorebirds:
Some of the same people that were hyping this system yesterday,are now the same that are ripping it.It's not everyone though.Just very little.Give 93l some time.It's not like these type of systems just ramp up in a hurry.


I never hyped this storm, nor am I RIPing it. Just saying it will take time.
Member Since: Posts: Comments:


Member Since: Posts: Comments:
93L seems to look better than it ever has. Everything points that this should be a major concern, it just has not panned out yet. We all know how these systems can explode... ex. Wilma Or hopefully never develop because outside forces that are yet to be determined at this time.
Member Since: Posts: Comments:
Quoting Hurricanes101:
um TN the GFDL still has mainly the same forecast today as it did last night


true. but it shows a much weaker system, i tend to favor the
HWRF solution right now but im done with trusting the models.
Member Since: Posts: Comments:
My 2pm graphics update:
Member Since: Posts: Comments:
Some of the same people that were hyping this system yesterday,are now the same that are ripping it.It's not everyone though.Just very little.Give 93l some time.It's not like these type of systems just ramp up in a hurry.
Member Since: Posts: Comments:
Golf, anyone?
Member Since: Posts: Comments:
If 93L starts getting a decent spin which it may do in next couple days, the chances to develop will skyrocket. Assuming all else stays the same and we don't get some unexpected shear or dry air.
Member Since: Posts: Comments:
Looks like a ull over S. Fl. moving off to the sw that I believe is what is pushing 93l northward and messing with its development. That was a problem last year for storms. imo
Member Since: Posts: Comments:
The moratorium stays in place while under appeal by the White House.
Member Since: Posts: Comments:
A broad circulation, caused by an anticyclone, this is why it's eye boggling. The storm is less organized because it has failed to blow up decent convection and develop a LLC. 20% is reasonable for now, should go back to 40-50% as it nears Jamaica tomorrow, or south of Jamaica, I'm still holding on a southern trend.
Member Since: Posts: Comments:
Greetings.
Just in briefly to say --
weather conditions in Trinidad are most 'peculiar' today.
during the morning the sky looked like dense Dust or even smoke down to the surface. Looked 'miasmic' and unhealthy. Like polution..
South winds right now, becoming s/e occasionaly.
Heavy thunderclouds with rumblings going on. Some very heavy showers dropping out of scattered cumulus,

But looking at the sat.maps and images, there is nothing overhead!!??

I love this strange weather........
Member Since: Posts: Comments:
Quoting Jeff9641:


THere for sure seems to be a nice mid level circulation just S of Haiti.

While I am the champion of there is no LLC COC etc..
It does appear some rotation is forming up..
There is still no COC or LLC but mid and upper levels do look to be organizing. There are mid upper level cloud going due south just to the west side of 16N 71W and due north just to the east of that point. Now once there is a point clouds are going east or stationary to the south of some point the question becomes is their a surface circulation under it.
But there is still the land interaction to contend with.
Member Since: Posts: Comments:
Has anyone else seen the new low preparing to depart the African coast???
Member Since: Posts: Comments:
Looking at the visible floater, I see two circulations:

*A low-level one at 15.5N, 75W.
*A mid-level one at 16.8N, 71.8W.

This might be the problem. LLC and MLC not stacked.

And it looks like the mid-level circulation wants to go NW into Haiti, while the LLC wants to go WNW past Jamaica to the south. Not sure how this is gonna play out.
Member Since: Posts: Comments:
TEXMEX Special ?

Member Since: Posts: Comments:
Quoting Patrap:

Floater - JSL Color Infrared Loop


Nice, you can really see the rotation on that one. I'm guessing by late tonight or tomorrow we'll have a depression.
Member Since: Posts: Comments:
Quoting Patrap:
Floater - Rainbow Color Infrared Loop


Thanks for these links Pat. While I know it hasn't been your intention, I had to relocate to my Moms place in Florida really quickly and don't have any of my links from my computer, so these have been very helpful. Thanks.
Member Since: Posts: Comments:
Quoting Drakoen:
Maybe after they see these 12z models they will up the chances...

I am starting to wonder if they forecast based on what the models show within a 48 hour period versus what they actually see.


Yep, you see them go out of the 48 hour window in the latest TWO when referring to conditions improving
Member Since: Posts: Comments:
Judge blocks Gulf offshore drilling moratorium



Credit: AP

A rig and support vessels are shown at the site of the Deepwater Horizon oil spill in the Gulf of Mexico near the coast of Louisiana, Monday, May 31, 2010. (AP Photo/Jae C. Hong)

by Michael Kunzelman / The Associated Press

wwltv.com

Posted on June 22, 2010 at 12:57 PM

Updated today at 1:07 PM

NEW ORLEANS -- A federal judge in New Orleans has blocked a six-month moratorium on new deepwater drilling projects that was imposed in response to the massive Gulf oil spill.

The White House says it will appeal the ruling.

Several companies that ferry people and supplies and provide other services to offshore drilling rigs had asked U.S. District Judge Martin Feldman in New Orleans to overturn the moratorium.

President Barack Obama's administration has halted the approval of any new permits for deepwater drilling and suspended drilling at 33 exploratory wells in the Gulf.

Feldman says in his ruling that the Interior Department failed to provide adequate reasoning for the moratorium. He says it seems to assume that because one rig failed, all companies and rigs doing deepwater drilling pose an imminent danger.

(Copyright 2010 by The Associated Press. All Rights Reserved.)
Member Since: Posts: Comments:
817. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting 69Viking:


Show me anywhere I said LLvs. If I didn't say it then don't quote me as saying it.
Quoting 69Viking:


Show me anywhere I said LLvs. If I didn't say it then don't quote me as saying it.


Um, 1st off I didnt attack you, I just said midlevel circulation, 2nd your the 1 whos doing the attacking, and its probably cause your upset the NHC is inline with what I'm seeing, Txmet and a few others.

What happens is alot of you dont want to accept a Mets or someone with weather knowledge who isnt a Met if they say something wont develop or isn't ready to develop. You start calling Me/Us downcasters when we tell ya why its not developing.

I have called out a few peeps before,,thats correct but thats after continued challenges to my forecasts that dont include a developing storm. Until something does come up, it is dreamcasting if you dont have evidence to back up something.

When the teacher teaches you something in school.. you should listen. When a Met or someone tells ya whats happening in here. You should listen, not challenge Me/Us.

We all have our opinions, but back up with data.

Also there is no need for your insults. I didnt insult you. End of Discussion about this.
Member Since: Posts: Comments:
Quoting iluvjess:


Perhaps the best post of the day!


And if there's another BP style blowout? What do we do with two?
Member Since: Posts: Comments:
Quoting extreme236:
I think some people are getting hung up on a single TWO. In all reality 93L will do whatever it will do. No TWO will change that lol


agreed lol
Member Since: March 10, 2010 Posts: 1 Comments: 7872
sorry guys, i was feeling opinionated today. [Laughs]
Member Since: Posts: Comments:
803. iluvjess 2:10 PM EDT on June 22, 2010
Quoting Patrap:

Breaking News
Judge blocks drilling moratorium

Judge blocks offshore drilling moratorium imposed by Obama administration after Gulf spill.


Perhaps the best post of the day!

white house says they gonna appeal it .
Member Since: Posts: Comments:
All I'm seeing in 93L is a region of unstable moist air being "pumped" by daytime heating and boosted by the uplift from this phase of the MJO. Since it hasn't had enough rotation to move the T-storms, they quickly become outflow dominated and collapse, which then decreases the formation of additional T-storms until the next daytime cycle comes around.

Rotation is the key here, and it's lacking right now. Water temps alone don't appear to be driving 93L at this point. Without rotation, Diurnal Max storms cannot form and maintain their development.

We saw this from 92L also, and everyone kept shouting "Look, it's organizing!" every single day.

What are the daytime air temps in that central Caribbean now? What's the P-water measurement?
Member Since: Posts: Comments:
Me tinks deirs a low pressa formn' at da suwface:
Member Since: Posts: Comments:
I think some people are getting hung up on a single TWO. In all reality 93L will do whatever it will do. No TWO will change that lol
Member Since: Posts: Comments:
92L had amazing spin for tropical disturbance, while 93L has always had very little.
Member Since: Posts: Comments:
Quoting clwstmchasr:


I thought conditions were favorable now????


cy·clone   [sahy-klohn]
–noun
1.a large-scale, atmospheric wind-and-pressure system characterized by low pressure at its center and by circular wind motion, counterclockwise in the Northern Hemisphere, clockwise in the Southern Hemisphere.

By definition, a Cyclone can range anywhere from a tropical depression to a hurricane... so long as it has a low pressure center and circular counter-clockwise wind motion.

That being said, there is a 20% chance of this storm organizing and forming both a low-pressure center and circular wind motion during the next 48-hours. Given the favorable conditions, I would say there is a 50% chance it will meet the definition of "cyclone" at the tropical depression level within 48-hours as it moves over these very warm Caribbean waters.
Member Since: Posts: Comments:
Quoting Drakoen:
Maybe after they see these 12z models they will up the chances...

I am starting to wonder if they forecast based on what the models show within a 48 hour period versus what they actually see.


Seems a Blend recently.

The Pkgs all are so dated by issuance,,were on to the real time by 2 Hours all the time.

Seems to me.
I dont wanna think about it.
Member Since: Posts: Comments:
new low on this map
Member Since: Posts: Comments:
Quoting Patrap:

Breaking News
Judge blocks drilling moratorium

Judge blocks offshore drilling moratorium imposed by Obama administration after Gulf spill.


Perhaps the best post of the day!
Member Since: Posts: Comments:
Quoting TexasHurricane:
Looks pretty good to me....maybe I need to get my eyes checked too.



I had my eyes checked out,and well it wasn't that bad.Just a lot of test to go through.
Member Since: Posts: Comments:

Floater - JSL Color Infrared Loop
Member Since: Posts: Comments:
Hurricane Celia (Category 2)
*NEW* Graphics Update
Time: 8am PDT/11am EDT
Images made by cyclonekid


Member Since: Posts: Comments:
Maybe after they see these 12z models they will up the chances...

I am starting to wonder if they forecast based on what the models show within a 48 hour period versus what they actually see.
Member Since: October 28, 2006 Posts: 57 Comments: 30615
http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8midshr.GIF

mid-level shear looks conductive for development,but:


http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8shr.GIF


upper-level shear is 10-40 knots(not so conductive)...
Member Since: Posts: Comments:
93L still has several days before it gets into the Gulf and then several more while in the Gulf

Still plenty of time to organize

Again just because the TWO development chances go down for the next 48 hours, does not mean the chances of the system developing at all are going down as well.
Member Since: March 10, 2010 Posts: 1 Comments: 7872
I still like the NHC tune on 93L. Notice they said 20% chance over then next 48 hours. It's reasonable because this has still yet to find a surface closed low level low. So 20% seems right, over the next 48 hours. After that, they said conditions are likely to get conductive for development in a few days. So they're not RIPing it, just saying development, if any, will be slow. Good call :)
Member Since: Posts: Comments:

Viewing: 846 - 796

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

Partly Cloudy
29 °F
Partly Cloudy