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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OK I got why it jumps all over.
In very basic terms they take the SAT/RADAR measured vorticity and condense it to a point.

Since the Vorticity is a long blob along or around the waves or right now half over land( they discount that part) THAT is where they seed the Storm with a bogus center


http://www.mmm.ucar.edu/wrf/users/tutorial/hurricanes/AHW_initialization.pdf
Member Since: September 1, 2009 Posts: 23 Comments: 1007
Quoting Jeff9641:


I can't stand that guy now day 65 of this disaster. I think there is some good news though as the navy has retrived over a millions barrels from the cap.


I was on Dauphin Island this weekend. Lots of activity and needed a pass to get on the west end. Only saw a few tar balls though. The Reserves are doing a great job of keeping everything organized and clean. Even a small storm in the Gulf will wreak havoc though....from Texas to Florida. Oil will be in the trees.
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Wunderkid

This shows it better. The blob on the right now has warmer cloud tops than the building convection SSE of Jamaica which is the 16N 75W area I referred to. Gone now.

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3492. IKE
15.6N and 76.6W....little to nothing there right now. Ain't nothing going to happen anytime soon.
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Plan of the Day


000
NOUS42 KNHC 221500
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1100 AM EDT TUE 22 JUNE 2010
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 23/1100Z TO 24/1100Z JUNE 2010
TCPOD NUMBER.....10-022

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (SOUTH OF JAMAICA)
FLIGHT ONE - TEAL 70
A. 23/1800Z
B. AFXXX 01AAA INVEST
C. 23/1330Z
D. 17.0N 77.5W
E. 23/1700Z TO 23/2100Z
F. SFC TO 10,000 FT

FLIGHT TWO - TEAL 71
A. 24/0600Z
B. AFXXX 0201A CYCLONE
C. 24/0100Z
D. 17.5N 79.5W
E. 24/0400Z TO 24/0830Z
F. SFC TO 10,000 FT

2. SUCCEEDING DAY OUTLOOK: CONTINUE 12 HRLY
FIXES IF SYSTEM REMAINS A THREAT.

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
JWP
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Quoting nishinigami:
ok, the GFDL was not what I wanted to see this morning :(

I have seen people joke on here about ants, but what do you do when you walk out on your porch first thing in the morning and see a crab walk by? I had a small 2.5-3" crab strolling along my front porch and I do not live near a beach. Bad sign??? lol

Kelley


crabcaster!
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3488. 34chip
How does anyone see Key West being effective by this wave or waves. Thanks
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Hi storm, earlier you made a comment about Mickey mouse lol. I saw that on the loop last frame. What's up with that?
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Quoting nrtiwlnvragn:
AL 93 2010062312 BEST 0 156N 766W 25 1010 WV


There is no way this can be possible. I am looking at low-level clouds going to the NW at that spot on the visible. If there's any low-level circulation I can see over in that area, it's all the way over at around 14.5N, 78.5W.
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Quoting wunderkidcayman:
I'm sorry kmanislanderI don't see what you are seeing please elaborate


Ignore the blob to the NE of that position and watch the rotation there. I suspect that is what is causing the blob to decline so quickly in structure as well as robbing its energy, hence the rapidly warming cloud tops.
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Quoting kmanislander:


I agree that it is being sheared now but more so by the anticyclone that is centered in the Western Caribbean. That 850 vort has been very persistent and should be monitored down the road.
Quoting jrweatherman:


Jeff, you said yesterday that this would be a depression this morning moving just north of Jamaica.
Still no center.
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3483. IKE
Quoting aquak9:
ok so if the recon info I posted is wrong, then post the correct recon info, please.

not challenging you by no means- but I'd like to KNOW when recon is going in please


Recon canceled.
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Quoting Jeff9641:


Center relocated to the position I said it would yesterday. I knew this was right.


Jeff, you said yesterday that this would be a depression this morning moving just north of Jamaica.
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Jeff9641 you called it. Everyone take a break sometime today if possible. You may need it later. The satellites will still be going anyway. I kind of like taking a few hours break to see if things develop.
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Quoting Thunderground:

Plan of the Day


000
NOUS42 KNHC 211400
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1000 AM EDT MON 21 JUNE 2010
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 22/1100Z TO 23/1100Z JUNE 2010
TCPOD NUMBER.....10-021

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK: POSSIBLE LOW LEVEL
INVEST NEAR 16.ON 77.0W AT 23/1800Z.

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


Not current, this is.
000
NOUS42 KNHC 221500
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1100 AM EDT TUE 22 JUNE 2010
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 23/1100Z TO 24/1100Z JUNE 2010
TCPOD NUMBER.....10-022

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (SOUTH OF JAMAICA)
FLIGHT ONE - TEAL 70
A. 23/1800Z
B. AFXXX 01AAA INVEST
C. 23/1330Z
D. 17.0N 77.5W
E. 23/1700Z TO 23/2100Z
F. SFC TO 10,000 FT

FLIGHT TWO - TEAL 71
A. 24/0600Z
B. AFXXX 0201A CYCLONE
C. 24/0100Z
D. 17.5N 79.5W
E. 24/0400Z TO 24/0830Z
F. SFC TO 10,000 FT

2. SUCCEEDING DAY OUTLOOK: CONTINUE 12 HRLY
FIXES IF SYSTEM REMAINS A THREAT.

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

Member Since: July 8, 2005 Posts: 259 Comments: 24016
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Quoting gordydunnot:
And now closing from the outside it's Herbert's Box trying to take over John Hope at the inside rail.Photo finish hold all tickets please.


It was only a matter of time...BTW, it's "Hebert Box", as in Paul Hebert...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Kinda looks like the crazy CMC solution from yesterday.
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I'm sorry kmanislanderI don't see what you are seeing please elaborate
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JB's Blog

WEDNESDAY 7 A.M.


Look Ma, a typhoon development in the Caribbean!

That's what you are seeing, folks! This is how typhoons develop in the Pacific out of large envelopes of competing low pressures. In the Pacific, it's not so much a tropical wave that suddenly flares up, but instead a large area of lowering pressure produced by the environment around it! Competing low pressures that move slowly enough that they can finally pull the energy into one center, and if they do, look out. The reason we are seeing this is because of the outlined pattern of the season.. The very warm water of the Atlantic Basin is lowering pressures more than normal over the United States and of course the adjacent coastal waters. In the meantime, the sudden shortening of wavelengths hemispherically means amplification is going on all over the place... the cold pockets aloft getting colder, the warm areas focusing and getting warm. That means pressures are going to fall in places and rise in others. One of the biggest keys to the idea this almost has to happen, development, is the big high that will break the heat wave for a few days next week. If you are going to raise pressures over the Great Lakes and Northeast like that, with so much warm water, look out.

Last night, I went into the dissertation of how this could be a strong storm and lo and behold, there is the Euro this morning with the farther east track, and of course that would imply the system gets stacked, and if it gets stacked, it gets jacked. It also means that the oil slick area could be directly impacted by this, and a lot of questions as to what a hurricane would do there could get answered next week at this time. While not etched in stone, that farther east track is more appealing to me by the minute. Why? Well remember, this is not a development with one particular wave, but the product of the OVERALL pattern producing the pressure falls and then the organization of the system... which can be in a variety of places in the western Caribbean. One sees that with the large area of spread out convection but its a sign a lot of energy can be bundled! And there in lies the key, there is a lot of energy, that if it gets focused can give us a powerful June storm. That long boring dissertation is below.

The system near 42 west is liable to develop next week, but that should stay up east of the states, ahead of the trough split that is going on.

There is big problem potential here, because if we get a trough split to interact with this, the storm could conceivably get pulled up into the states, stuck, then turn west under what should be a building ridge over the Great Lakes and the Ohio Valley during the July 4th weekend. I can't tell you what a challenge this is, as it's still early enough in the year for the trough to dip in that far south then split, but we are dealing with the kind of energy with the water so warm that it is associated with midseason storms. So strap in, here we go. The tropics are bubbling and the lid is about to pop off for our first impact threat of the season.
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Crabs don't like oil. Kman spot on,that is where some were giving Storm W a hard time this morning because he pointed out that was the center of the anticyclone also the Dvorak center shows there.It caught my eye when that storm pop up just off the se coast of Jamaica now some are firing s and east.
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Plan of the Day


000
NOUS42 KNHC 211400
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1000 AM EDT MON 21 JUNE 2010
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 22/1100Z TO 23/1100Z JUNE 2010
TCPOD NUMBER.....10-021

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK: POSSIBLE LOW LEVEL
INVEST NEAR 16.ON 77.0W AT 23/1800Z.

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
JWP
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check kmanis 16/75 for the "mid level"/low level/hope rule/mass of showers. It's trying. It's getting to the west Mr. HOpe.
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Regardless, this doesn't look good for the oil mess.

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That's enough for me for now. This all needs a few hours to gel some.

C U later
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3468. aquak9
ok so if the recon info I posted is wrong, then post the correct recon info, please.

not challenging you by no means- but I'd like to KNOW when recon is going in please
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TWC just stated the Recon flight today has been cancelled, can anyone verify?
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AL 93 2010062312 BEST 0 156N 766W 25 1010 WV
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Good morning all! Wish I had time to stay awhile, but I have a sick 3 year old at home today. Can anyone give me any quick, useful updates on our invest of choice for the week? Thanks...
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Quoting StormW:


Good eye kamn! Now gee, where is that upper level anitcyclone near...LOL?



I knew you would like that !
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Okay, so here is a question for the experts...what would cause an MVC to form repeatedly south of Hispaniola while the vortex seems to be building (or whatever the correct term is) east of there around Jamaica? And is this reappearing MVC stealing energy from where the actual "center" is and thus impeding development?
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Quoting blueyedhrlyridr:
We will know more once it emerges into the Southern Gulf. Looks like Tx might bear the brunt of this one.


Yeah it could. Hope not. :(
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Quoting StormW:
Check out the "new" on NHC Surface Analysis...sheesh:



Why the sheesh? Do you disagree with it?
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting Jeff9641:


This thing may have a ticket to BP. This could cause Hayward to resign.


I'm surprised he's not in a looney bin already. Is there some way we can send these storms to the U.K.? My apologies Brits, we love you and you know it.
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Quoting StormW:
Check out the "new" on NHC Surface Analysis...sheesh:



Take a look at my post 3442. Perhaps that is where the new low comes from
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Quoting StormW:
Check out the "new" on NHC Surface Analysis...sheesh:



Lining em up.
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Quoting kmanislander:
The NHC may need to move the circle over 16N 75W.


That's what I thought earlier.
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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.