93L slow to develop, but bringing heavy rains to Haiti
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
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The setup that WSVN uses just keeps me coming back. They may be a over-dramatized station, but they do become reliable when something does occur, or so in my opinion. Are any other news stations any better?
Ok strike that thought about water stirred.
Well something is hindering this thing!
Is leftover energy good for a spark.
But needs to clear the field to get a game on?
In other words lots of leftover energy there to spark a flair.
But it just needs time to settle down and come together.
I am grasping here but there is a reason it is not coming together even a little more quickly.
Thank you very much!
whoa... some one tell me what is going on in this picture.
img src="http://" alt="" />
Anytime Cajun :-)
that's what i've been thinking, but i didn't have the confidence to say it. well, i didn't think about the anticyclone part, because i only just now figured out how to spot one. but i've been thinking that the LLC is under there.
Behave, and have a good night all.
June 22, 2010 - 8:35 PM EDT - 93L -
Well, at this point, something is holding up production of that long awaited LLC. Were the amateurs here, maybe were missing something?
Area forecast discussion
National Weather Service New Orleans la
844 PM CDT Tuesday Jun 22 2010
Update...
Sounding discussion...
no problems with the flight this evening. A midlevel low pressure
system will continue to bring rain chances to our area tonight
through tomorrow. This moisture rich atmosphere will cause
scattered to wide-spread showers and thunderstorms over the next
24 to 48 hours. Severe weather is not expected because the
atmosphere is to saturated and winds are not favorable.
Precipitable water value is around 2.29 inches with a lifted index
of -6.7. Storm motion is around 5 miles per hour and winds are light and out
of the east near the surface and aloft.
Cl
&&
Previous discussion... /issued 149 PM CDT Tuesday Jun 22 2010/
Short term...(tonight-thursday)...inverted trough off the coast of
Louisiana with associated upper level disturbance creating enough
convergence with ample deep layer moisture available for numerous
showers/isolated thunderstorms across the coastal waters. Earlier
today this activity was having a hard time penetrating inland...but
with surface heating early this afternoon expect coverage &
intensity of convection to increase over land areas. The main
threats will be locally heavy rainfall...frequent lightning in a few
storms and downburst winds 40 to 50 miles per hour in stronger cells. Expect
activity to wind down later this evening but will still carry a
20%-30% pop overnight for lingering convection.
This system will be slow to exit the area overnight/Wednesday moving
east to west and will provide a high end scattered chance of
precipitation again on Wednesday as we will have a deep fetch of
onshore flow...though afternoon maximum temperatures are forecast to
recover a couple/few degrees higher than highs realized today across
most areas. Pop chances will decrease to 20%-30% on Thursday as the
upper level system migrates further away from the area taking deeper
layer moisture with it. Highest pop chances on this day will reside
across the west.
C U Nash. Have a good one.
Or just more CMC nonsense.
I heard him today too.... He confused me....so I'm glad that you said something...lol...
A Double Whammy from the Se..
Fujiwara effect
True, but everything I've seen indicates very favorable conditions.
Due East of the NE coast of Nicaragua and Honduras right now headed West.
If this novice may.
I am not sure where you are looking.
But is it possible you are looking at the edges of the anticyclone that was previously slightly out of sinc?
And is possibly now coming back more in line above?
WTPZ35 KNHC 230231
TCPEP5
BULLETIN
TROPICAL DEPRESSION FIVE-E ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
800 PM PDT TUE JUN 22 2010
...AND YET ANOTHER TROPICAL DEPRESSION FORMS IN THE EASTERN
PACIFIC...
SUMMARY OF 800 PM PDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...11.0N 93.4W
ABOUT 380 MI...610 KM SSE OF SALINA CRUZ MEXICO
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/HR
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 9 MPH...15 KM/HR
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES
WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.
DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
SATELLITE IMAGES INDICATE THAT THE AREA OF LOW PRESSURE SOUTH OF
MEXICO HAS BECOME TROPICAL DEPRESSION FIVE-E. AT 800 PM PDT...0300
UTC...THE CENTER OF THE NEWLY FORMED TROPICAL DEPRESSION WAS
LOCATED NEAR LATITUDE 11.0 NORTH...LONGITUDE 93.4 WEST. THE
DEPRESSION IS MOVING TOWARD THE WEST-NORTHWEST NEAR 9 MPH...15
KM/HR. THIS GENERAL MOTION IS EXPECTED TO CONTINUE DURING THE NEXT
DAY OR TWO WITH A GRADUAL DECREASE IN FORWARD SPEED.
MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/HR...WITH HIGHER
GUSTS. SOME STRENGTHENING IS POSSIBLE AND THE DEPRESSION COULD
BECOME A TROPICAL STORM ON WEDNESDAY.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB...29.71 INCHES.
HAZARDS AFFECTING LAND
----------------------
NONE
NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...200 AM PDT.
$$
FORECASTER AVILA
Total heat content of the ocean
As most of you are aware, hurricanes generally require sea surface temperatures (SSTs) of at least 80 F (26.5 C) to exist, and the hotter the water, the better.Hurricanes also like to have these warm ocean waters extend to a depth of several hundred feet, since the winds of a hurricane generate ocean turbulence that stirs up colder water from the depths to the surface. Hurricane that pass over a region of ocean with very deep warm waters can intensify explosively; this happened with Katrina, Rita, and Wilma in 2005. A good way to monitor this total oceanic heat is with the Tropical Cyclone Heat Potential (TCHP) imagery prepared daily by NOAA using satellite measurements of the height of the ocean surface. Hotter water expands, creating a higher water surface that the satellite can measure.
Let's take a look at the TCHP data from July 28 this year, and compare it to last year (Figures 4 and 5). The units of measurement are in kilojoules per square centimeter, and any value greater than 20 kJ/cm**2 (a medium blue color) is high enough to support a Category 1 hurricane. A TCHP greater than 90 kJ/cm**2 (orange color) can lead to rapid intensification of a hurricane. The TCHP image from last year shows a large area of oranges and reds in excess of the 90 kJ/cm**2 threshold for rapid hurricane intensification covering most of the Gulf of Mexico, Caribbean, and tropical Atlantic. A red bullseye in the Gulf of Mexico marks the Loop Current Eddy that broke off in the Gulf last July, and helped fuel Katrina and Rita to record intensities.
In contrast, the TCHP image for this year shows the oranges and reds covering just a portion of the western Caribbean and southern Gulf. There is much less heat energy available to fuel intense hurricanes, and thus we should see fewer of them this year than in 2005 (or 2004, which also had very high TCHP values). However, we again see an ominous looking red bullseye in the central Gulf of Mexico this year, similar to what was there last year.
I think the GFDL holds the title for the disaster tonight. 103kts, and strengthening, headed right for NOLA.
LOL! You can tell it's Avila who wrote it when the head title is:
"...AND YET ANOTHER TROPICAL DEPRESSION FORMS IN THE EASTERN
PACIFIC..."
But I got to say, 5 tropical depressions in like 10 days is pretty crazy.
When looking at the CMC think of this quote "my life has been a series of disasters the majority of which have never occurred".It will blow up more systems than your great aunt has hair on her chin. I wouldn't pay it much mind rightnow
"
Been noticing this evening it's interacting with the MLC up by the Dominican Republic.
Why?
Roughly 17N/72W.
Organizing. Anti-cyclone to the W is both +/-.
Have to see how it pans out.
It just needs to move south and get a LLC going.
This was my Forecast direction and Intensity....from yesterday at 10am
This loop shows easily a COC may not be a LLC but, its there at ...17.3N 72.8W Speed it up as it is now coming together it appears...
Yeah. I loved what he had to say about TD 5-e. Lol!
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