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

By: Dr. Jeff Masters , 01:50 PM GMT am 22. Juni 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: 196 - 146

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

NHC expecting a low pressure center south of Jamaica tomorrow morning...

Member Since: Posts: Comments:
Hurricane Celia (Category 2)
*NEW* Graphics Update
Time: 8am PDT/11am EDT
Images made by cyclonekid
Click on images to make them larger


Member Since: Posts: Comments:
"The waiting is the hardest part
Every day you see one more card (wave)
You take it on faith, you take it to the heart
The waiting is the hardest part"


All the best...

Tom Petty

Member Since: Juli 20, 2008 Posts: 0 Comments: 152
Quoting Patrap:


Sleep?

I just woke up ..LOL


Ok. Then get a cup of coffee. :)

How all is well on your side of the GOM.
Member Since: Posts: Comments:
Quoting twhcracker:
I said it woulod be code red > 50 % chance of developing today by 2 PM central. and i based it on how many cricket chirps per hour divided by 3 then add the year i was born minus 1700. I have rarely ever been wrong.
I've used this formula. I find if you divide the result by the number of new ant hills you've seen in the last week, times 2..the end result is deadly accurate. Forget about rarely, you'll NEVER be wrong.
Member Since: Posts: Comments:
This site is a addiction
Member Since: Posts: Comments:
Quoting sammywammybamy:


Better than the original song.


Lol I agree, being a teen I absolutely hate that song, they used to play that all the time on WRVQ or Q94 if you are familiar with Richmond
Member Since: Posts: Comments:
.
Member Since: Posts: Comments:
Storm Relative 16km Microwave-Based Total Precipitable Water Imagery



Storm Relative 16km Microwave-Based Total Precipitable Water Imagery

The relative lack of environmental moisture around a tropical cyclone can adversely affect the deep convection and negatively impact the storm and result in weakening. Luckily there is several low earth orbiting satellites that provide estimates of the amount of water vapor in the atmospheric column, commonly referred to a total precipitable water (TPW). TPW estimates from a single satellite platform, however, often suffer from inadequate temporal coverage and poor refresh rates. To partially rectify this issue, the information from three Advanced Microwave Sounding Units (AMSU) on NOAA satellites and five Special Sensor Microwave Imagers (SSMI) on DOD satellites are combined via a blending algorithm described in Kidder and Jones (2007). Such a product has a refresh rate of approximately 6 hours and a spatial resolution of approximately 16km. This product shows the TPW around the tropical cyclone and to further enhance its utility the images are centered on the current storm location and when looped show TPW features moving to and from the storm center.


Member Since: Juli 3, 2005 Posts: 426 Comments: 129093
Quoting Skyepony:


Been looking at the CMC this morning??? This morning aka ..solutions where nature will clean up your mess.


omg two hitting near me. are you kidding about a natural solution??
Member Since: Posts: Comments:
Anyone else think a center is trying to develop in that blob just south of Hispaniola
Member Since: Posts: Comments:
Quoting Dakster:



PAT -- Funny... But you really should get some sleep.


Sleep?

I just woke up ..LOL
Member Since: Juli 3, 2005 Posts: 426 Comments: 129093
Quoting IKE:

looks like a mess to me.
Member Since: Posts: Comments:
Quoting sammywammybamy:


Better than the original song.



PAT -- Funny... But you really should get some sleep.
Member Since: Posts: Comments:
Member Since: Juli 3, 2005 Posts: 426 Comments: 129093
Quoting Hurricanes101:
I will say the convection appears better organized this morning
Yes. It looks to be organizing slowly. It is my belief starting tomorrow evening this thing is going to gather strength faster than forecast.jmo
Member Since: Posts: Comments:
175. Skyepony (Mod)
Quoting twhcracker:


what does that mean?? There is a little yellow blob right over my house!


Did you scroll to the right & click on FWD? If not, do that...
Member Since: Posts: Comments:
Quoting txag91met:
NAM is horrible with tropical systems...see what the GFS does.


I can't tell u how many times they forecasted a major hurricane hitting the coastline when it is poorly organized, believe me!!!
Member Since: Posts: Comments:
Quoting tropicfreak:


well yesterday u doubted me about them changing it to orange, and guess what, oh it did!! Maybe she will be right about this.


*Golf Clap*

Member Since: Posts: Comments:
I clicked on show "best" and only three posts were left on this page..lol!
Member Since: Posts: Comments:
Also... The CMC is too funny!
Member Since: Posts: Comments:
GOM IR Loop

Member Since: Juli 3, 2005 Posts: 426 Comments: 129093
Chalk one up for climatology!
Member Since: Posts: Comments:
Quoting Hurricanes101:


Well when you give the crickets steriods, now thats just cheating


well yesterday u doubted me about them changing it to orange, and guess what, oh it did!! Maybe she will be right about this.
Member Since: Posts: Comments:
Quoting IKE:
Looks like it's a wait til the western Caribbean for 93L....

12Z NAM @ 84hrs.....

NAM is horrible with tropical systems...see what the GFS does.
Member Since: Posts: Comments:
Quoting tropicfreak:


Geez looks like impatience is taking its toll here on this blog. I tell you what, if it doesn't develop in the next 2 days, then i will hang upside down on the chair I'm sitting on while typing.


I think the blog will be slower today than it was yesterday...unless the NHC increases the percentage chances or it really starts to look better. We'll see.
Member Since: Posts: Comments:
Quoting StormW:
Yuck!



Can you change that graphic?? Don't like that either.
Member Since: Posts: Comments:
From my lurking experience, 93L seems to be the classic tropical disturbance. ie. it looks impressive but leaves us guessing for days on if/where a center will form
Member Since: Posts: Comments:
Good Morning.... looks like 93l is starting to organize little better now....
Member Since: Posts: Comments:
Quoting twhcracker:
I said it woulod be code red > 50 % chance of developing today by 2 PM central. and i based it on how many cricket chirps per hour divided by 3 then add the year i was born minus 1700. I have rarely ever been wrong.


I believe the NHC uses the same method!
Member Since: Posts: Comments:
Quoting helove2trac:
I wish it would just develope then we could deal with what comes after that the waiting game is whats killing me


Geez looks like impatience is taking its toll here on this blog. I tell you what, if it doesn't develop in the next 2 days, then i will hang upside down on the chair I'm sitting on while typing.
Member Since: Posts: Comments:
Quoting rcmansour: you guys RIP 93 L. Hurricane center already lowers probability of development. Again lets talk about the Pacific. Atlantic has nothing going on till August


I think it will be earlier than August. July is looking like it will be quite active. GFS is picking up on some activity in the next couple of weeks. There is going to be a bunch of healthy waves out there during the month of July.
Member Since: Posts: Comments:
Quoting Hurricanes101:


I saw a lot of people scream this was going to be a TD today, the more experienced people here stayed realistic

I think most of us knew this would take a few days to develop, if it does at all


Glad your back and i am sorry about yesterday! But, with that i hope you can now understand why i posted it was not well organized Structurlly as was said. Again Sorry!
Member Since: Posts: Comments:
Quoting twhcracker:
I said it woulod be code red > 50 % chance of developing today by 2 PM central. and i based it on how many cricket chirps per hour divided by 3 then add the year i was born minus 1700. I have rarely ever been wrong.


Well when you give the crickets steriods, now thats just cheating
Member Since: Posts: Comments:
The first mission will be tommorow afternoon.

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.
Member Since: Posts: Comments:
Quoting Patrap:
Nothing like being told at 10 am.

LOL


LOL
Member Since: Posts: Comments:
I said it woulod be code red > 50 % chance of developing today by 2 PM central. and i based it on how many cricket chirps per hour divided by 3 then add the year i was born minus 1700. I have rarely ever been wrong.
Member Since: Posts: Comments:
93L has nothing @ the surface. Pressures are high and not falling still. The LL surge of the carribean is disrupting any chance for this to consolidate a LLC... it will take a few days.. maybe when its west of Jamaica it will have a slight chance. I give this still a 30% chance of developing within 2-3 days.
Member Since: Posts: Comments:
Nothing like being told at 10 am.

LOL
Member Since: Juli 3, 2005 Posts: 426 Comments: 129093
149. srada
Good Morning Everyone

so we still dont have a center to the storm yet? so the models runs are still pointless..until those models can centralize on a center, we will have a wait and see situation..the fact that some of the models dont even develop a storm where the conditions are favorable just proves that point
Member Since: Posts: Comments:
93L might take another day or two to develop a closed surface low. Just sayin'.
Member Since: Posts: Comments:
I will say the convection appears better organized this morning
Member Since: Posts: Comments:
146. IKE
Member Since: Juni 9, 2005 Posts: 23 Comments: 37860

Viewing: 196 - 146

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

Scattered Clouds
54 °F
Teils Wolkig