99L a threat to develop; damage from Typhoon Megi still largely unknown
Heavy thunderstorm activity has increased and grown more organized this morning over the southwestern Caribbean between Honduras and the Cayman Islands, in association with a tropical disturbance (Invest 99L). The storm is bringing heavy rain to the Cayman Islands; two inches has fallen so far this morning at Savannah on Grand Cayman Island. Recent satellite imagery shows that 99L has some rotation, and the winds on the northeast coast of Honduras at Puerto Lempira have shifted to the west-northwest, implying that 99L may be developing a surface circulation. Wind shear is a moderate 10 - 20 knots, which is low enough to allow some slow development. Water vapor satellite loops reveal that the atmosphere in the Western Caribbean is moist enough to support development, and the waters beneath are plenty warm, at 29°C. The latest SHIPS model forecast predicts that wind shear over the Western Caribbean will mostly remain in the moderate range, 10 - 20 knots, for the remainder of the week. The current north-northwest motion of 99L should continue until Wednesday, when a strong ridge of high pressure is forecast to build in, forcing 99L to the south or west. However, steering currents will be weak Wednesday through Friday, making it difficult to predict where 99L may wander to. The only models that develop 99L are the GFDL and HWRF. The GFDL model predicts that 99L will spend enough time over water to develop into a hurricane, and brings the storm to the coast of Mexico's Yucatan Peninsula on Sunday morning. The HWRF model has 99L making landfall over Honduras late this week, before the storm has a chance to develop into a hurricane. NHC is giving 99L a 40% chance of developing into a tropical depression by Thursday. I believe the odds are higher, near 60%. The Hurricane Hunters are on call to investigate 99L this afternoon.
Figure 1. Morning satellite image of Invest 99L.
Damage from Super Typhoon Megi still largely unknown
The power is still out and communications are down over the majority of the northern portion of the Philippines' Luzon Island blasted by Typhoon Megi yesterday, so the extent of the destruction wrought by the great storm is still largely unknown. Preliminary news reports indicate that at least 10 people died, and the northern Philippine province of Isabela suffered severe damage. Megi hit Luzon on Monday morning at 3:30 UTC as a Category 5 super typhoon with sustained winds of 165 mph and a central pressure of 914 mb. Baguio near the west coast of northern Luzon received 7.72" of rain from the storm, and many mountainous regions likely received over a foot of rain.
Figure 2. Rainfall rates in excess of 1 inch per hour (orange colors) were observed by the polar-orbiting F-18 satellite in association with Megi at 00:40 UTC October 19, 2010. Image credit: Navy Research Lab, Monterey.
Passage over Luzon Island destroyed Megi's eyewall and inner core region, and the storm compensated by expanding and intensifying the portions of its circulation that were over water. Now that its center is back over water in the South China Sea, Megi has re-developed its inner core and has built a formidable new eyewall. At the same time, Megi has been able to maintain its larger size, and is now a much larger typhoon than when it hit the Philippines. This is similar to what happened to Hurricane Ike in 2008 when it passed over Cuba, and helped give Ike a very destructive storm surge when it came ashore over Texas. Wind shear is a low 5 - 10 knots over Megi, and the waters of the South China sea have a very high total heat content to great depth, so Megi should be able to intensify into a very dangerous Category 4 storm by Thursday. The larger size of Megi means that it will be able to deliver a significant storm surge in excess of ten feet to the coast of China of Friday or Saturday, when the storm is expected to make landfall near Hong Kong. As the storm approaches the coast on Friday, wind shear is expected to rise to the moderate or high range, and the total heat content of the ocean will drop significantly, so some weakening is to be expected. Still, Megi will probably hit China as a major Category 3 typhoon,bringing a significant storm surge, high winds, and widespread torrential rains that will likely make this a multi-billion dollar disaster for China.
"Daily Downpour" airing this afternoon
Our live Internet radio show, "Daily Downpour", will be airing today at 4pm EDT. The call in number is 415-983-2634, or you can post a question to broadcast@wunderground.com. You can tune in at http://www.wunderground.com/wxradio/wubroadcast.h tml, and I'll be discussing the latest info on Invest 99L with hosts Shaun Tanner and Tim Roche.
Jeff Masters
Reader Comments
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Thanks for the confirmation to the east.
Hi, I didn't read back. Was there some discussion about motion ?
Yes i can agree with that. I have had no rain in october as of today. The grass looking a little blah. At least i dont have to cut it 4 weeks now.
...steering currents will be weak Wednesday through Friday, making it difficult to predict where 99L may wander to.
thus the spider model.
Good Evening, same thing I thought , though I stated a drift ENE a few post back, what I don't like is slow movement, this system IMO has the potential to just sit , intensify and create havoc for us, but thats my take only!
I can't stay on long so bye
The same two problems that have plagued every system this year, namely dry air and shear. 99L is surrounded by dry air and has been ingesting some today. In addition, the shear tendency map indicates increasing shear all around the system today. In fact, it sits now in a very small pocket of relatively low shear.
In summary, conditions aloft not entirely ideal for development.There is an anticyclone nearby but not directly overhead the center.
if michael is to be he'd best stay in the caribbean.
It looks like the whole BLOB is going to flow NE into East Cuba and into the Bahamas?
Live in North Florida! Could use the rain!
I was away from my computer for a huge swathe of the day and evening and came back to see that little red circle on the NHC site (no longer yellow or orange). What happened? South Florida in the clear?
Who is Michael ??
You mean Richard, or Dick to his friends ?
Richard is the next TC in the Atlantic :OP
roflmao
how close to Hong Kong will Megi make landfall?
it looks more north than forecasted earlier today.
Will that moving air ahead of that dry air move it east or will that thing over those other states let it move north and to that other place?
Sorry. I am not making any sense at all...
Over the next few days, the upward MJO motion will moisten the Caribbean :O)
Hong Kong is at 20N / 114E
You did know what I mean??? Thank God. That was embarrassing. Plus my Facebook postings have been off all day. I need to lay off the coffee and get some sleep....
First of all the GFDL does not perform well on a system that has not yet formed so discount that for now. Current steering calls for weak flow in the NW Caribbean which would promote very slow motion or a stall such as we are seeing now.
If it does get to Cuba the conditions North of there are so hostile that not much would remain of it unless we get a rapid fall of in the shear from the sub tropical jet and that is unlikely this late in the season with conditions such as they are.
Here is the updated steering
TIA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
237 PM EDT TUE OCT 19 2010 Link
FARTHER EAST...THE MODELS ONCE AGAIN INITIALIZE AN UPPER LEVEL
RIDGE THAT EXTENDS ACROSS CENTRAL AMERICA AND MOST OF THE
CARIBBEAN/ GREATER ANTILLES. LIFTING OVER THIS AXIS...THE MODELS
SHOW A SHORT WAVE TROUGH OVER THE EASTERN GULF/FLORIDA
PENINSULA...WHICH SLOWLY TRACKS TO THE NORTHEAST. THIS WILL THEN
SET THE STAGE FOR A LONG WAVE TROUGH TO AMPLIFY ACROSS THE EASTERN
USA/WESTERN ATLANTIC TO THE EASTERN GULF OF MEXICO THROUGH 48-60
HRS...TO THEN MOVE INTO THE WESTERN ATLANTIC BY 72 HRS. AT UPPER
LEVELS...AS THE POLAR TROUGH AMPLIFIES...IT WILL PRESS AGAINST THE
SUBTROPICAL RIDGE...FLATTENING THIS AXIS WHILE DISPLACING IT
SOUTH. AT 500 HPA THE RIDGE WILL SPLIT IN TWO CELLS...THE
AFOREMENTIONED ONE OVER MEXICO/WESTERN GULF AND A NEW ONE ACROSS
THE EASTERN CARIBBEAN-CENTRAL ATLANTIC. THIS WILL FAVOR A WEAKNESS
IN THE HEIGHT FIELD ACROSS THE NORTHWESTERN CARIBBEAN BY THE END
OF THE FORECAST CYCLE.
AT LOW LEVELS A BROAD TROUGH/LOW PRESSURE AREA OVER THE WESTERN
CARIBBEAN CONTINUES TO FAVOR ORGANIZED DEEP CONVECTION...WITH
CELLS BUILDING/TRAINING ACROSS JAMAICA-CAYMAN ISLANDS. MODELS
CONTINUE TO MAKE CYCLE-TO-CYCLE CORRECTIONS TO THIS SYSTEM...AS
THEY TRY TO TAKE INTO ACCOUNT THE EVOLVING MID LEVEL WEAKNESS IN
THE HEIGHT FIELD ACROSS THE WESTERN CARIBBEAN. SO THIS REMAINS A
HIGH UNCERTAINTY FORECAST. ALSO NOTE THAT THE NHC IS EVALUATING
THIS SYSTEM FOR POSSIBILITY OF TROPICAL CYCLONE FORMATION...AND
THEY WILL ISSUE THE OFFICIAL FORECAST. ACROSS JAMAICA TO THE
CAYMAN ISLANDS IT WILL SUSTAIN ACCUMULATION OF 15-20MM/DAY AND
MAXIMA OF 30-60MM/DAY THROUGH 36 HRS...WITH MAXIMA TO SURGE TO
35-70MM/DAY BETWEEN 36-72 HRS. OVER NORTHERN HONDURAS EXPECT
ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF 30-60MM THROUGH 36
HRS...TO DECREASE TO 20-30MM/DAY THROUGH 48-72 HRS. UNDER
INFLUENCE OF THE SUBTROPICAL RIDGE...SOME OF THE MOISTURE WILL
LIFT NORTH ACROSS CUBA TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 20-35MM/DAY THROUGH 24 HRS. BY 24-48 HRS THE MAXIMA
WILL INCREASE TO 35-70MM/DAY.
There you have it, weak steering aloft leading to uncertainty with the models.
Odds are good 99L or "future "R" named storm" will most likely not move toward TX.
The sub-tropical jet is near 30 N latitude and winds speeds are over 40 KTS.
He or it will get pushed away from TX!
its should be red
http://tc.met.psu.edu/
sorry it took so long
At least 24 hours the way it is looking now. I would not be surprised to see the 70% come down to 60 or 50 at 11.
Sounds good to me. :) I noticed the 12z CMC and NOGAP had it coming into the SW GOM via the Yucatan but then killed it before it could make landfall. I'm assuming that would be 40kts of shear should it head this way?
Here is the above address in link form Link
thats what happened with Paula and then it bursted into a cat 2 hurricane
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