Western Caribbean disturbance 96L close to tropical depression status
A region of disturbed weather in the Western Caribbean (Invest 96L) has become more organized this morning, and is close to tropical depression status. A hurricane hunter aircraft is scheduled to investigate 96L this afternoon at 2 pm EDT to see if a tropical depression has formed. The system is located just offshore from the Nicaragua/Honduras border, and is bringing heavy rains to northeastern Honduras. Visible satellite loops show that 96L is close to having a well-developed surface circulation, but the heavy thunderstorm activity is all on the west side of the center, due to a large region of dry air to the east. Wind shear is a moderate 10 - 20 knots due to strong upper-level winds out of the east, and these winds are injecting dry air into 96L's east side, keeping any heavy thunderstorms from developing on that side. Water temperatures are very warm, 29 - 30°C, and these warm waters extend to great depth.
Figure 1. Morning satellite image of 96L.
Forecast for 96L
I expect 96L will be able to organize into a tropical depression later today or on Monday, though this process will be slowed by the dry air to the storm's east, and perhaps by proximity to the land areas of Nicaragua and Honduras. NHC gave 96L a 60% chance of developing into a tropical depression by Tuesday in their 8 am Tropical Weather Outlook today. Steering currents favor a motion to the west-northwest or northwest, and it is likely that heavy rains from 96L will spread over Belize by Tuesday night, when the storm will probably be called Tropical Storm Rina. Heavy rains from the storm will spread over Mexico's Yucatan Peninsula, including Cozumel and Cancun, by Wednesday afternoon. On Wednesday, 96L will be encountering a dry airmass with high wind shear that lies over the extreme northwestern Caribbean. Since 96L is a small storm, these hostile conditions should cause the storm to weaken significantly before any potential landfall occurs.
97L
A broad region of low pressure near 11°N, 55°W, about 300 hundred miles east of the southern Lesser Antilles Islands (Invest 97L), is moving slowly west-northwest towards the Lesser Antilles. This low has very limited heavy thunderstorm activity, due to dry air. NHC is giving 97L just a 10% chance of developing into a tropical depression by Tuesday. 97L is under a moderate 10 - 20 knots of wind shear, and this shear is expected to drop to the low range, less than 10 knots, by Monday, when the storm will be in the Eastern Caribbean Sea. By the time 97L approaches Jamaica in the Central Caribbean on Friday, the storm should find a moister environment, and could develop into a tropical depression then, as predicted by the NOGAPS model.
Jeff Masters
Reader Comments
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This happens a lot with tropical waves when they emerge off of Africa as they usually face 20-30 knots of easterly shear, which doesn't totally destroy the tropical waves because they are moving towards the west with the shear.
Trough coming through Florida and the NHC forecast timeline for Rina do not match up for a Florida problem. Just have to wait and see.
Storms can move along with shear, or at an angle or back against shear. But net shear is net shear. Shear is not the velocity of the upper level airflow. The value of shear is the relative difference between the storm center's velocity and the upper level winds' velocity.
*Click image to enlarge (image can further be enlarged in the Link Window by clicking anywhere on it)
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AT 1100 PM EDT...0300 UTC...THE CENTER OF TROPICAL STORM RINA WAS
LOCATED NEAR LATITUDE 16.4 NORTH...LONGITUDE 82.2 WEST. RINA IS
MOVING TOWARD THE NORTH-NORTHWEST NEAR 8 MPH...13 KM/H...AND THIS
MOTION IS EXPECTED TO CONTINUE TONIGHT. A TURN TOWARD THE NORTHWEST
AND THEN THE WEST-NORTHWEST IS EXPECTED ON MONDAY. ON THE FORECAST
TRACK...THE CENTER OF THE DEPRESSION IS EXPECTED TO PASS NORTH OF
THE NORTHEASTERN COAST OF HONDURAS DURING THE NEXT COUPLE OF DAYS.
depression????
Off topic, but do any South Florida residents think the Dolphins are gonna **** for Luck?
Thank you very much!
That's not really the reason though. It's the structure of the tropical waves that allows easterly shear to actually aid them, because convection naturally wants to develop east of the wave axis, so having the shear push it off to the west allows it to constantly regenerate and fill out the wave.
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Regarding the 11pm discussion, I also found it very well-written by Stewart...that is a great example of how the analysis and forecast should be done.
LOL! YES!!
AL182011 - Tropical Storm EIGHTEEN
Enhanced Infrared (IR) Imagery (4 km Mercator)/ loop
..click image for loop
Hi Levi...Read back and tell me if my reasoning on Rina has any merit.
Evening stone.
What's that supposed to mean?
I thought you wanted me to talk that way. Nice analysis before.
TD #18
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)
Dynamic Models (More sophisticated models)
Early Model Wind Forecast
What has eyes and can't see?
WOW what a butt whippin your Saints put on the Colts tonite......WOW
Haha I gotta agree too. Luck is the future!
Grothar?
RAMSDIS Floater
I've seen him here before but don't know him. I know he's well liked but never talked to him before he left.
But I was thinking of a potato ;)
Agree for sure....but the shear will be a problem for anything that far North unless things really change a lot....WHICH MIGHT HAPPEN
Tampa? Very unlikely rina ever tracks that far north in my opinion. If this storm were to make a pass at sfl it will in a weakened state. Very hostile upper environment lies in the gulf at the present time.
The 4 line-segments represent Invest97L's now westnorthwestward path
Copy&paste 10.9n55.7w-11.4n55.8w, 11.4n55.8w-11.6n56.0w, 11.6n56.0w-11.7n56.3w, 11.7n56.3w-12.0n56.9w, bgi, slu into the GreatCircleMapper for more info
The previous mapping (for 23Oct_6pmGMT)
Viewing: 851 - 901
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