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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AL, 99, 2010101918, , BEST, 0, 170N, 830W, 30, 1009, LO, 34, NEQ, 0, 0, 0, 0, 1012, 250, 50, 0, 0, L, 0, , 0, 0, INVEST, S
(~ 29.82 inHg)
WE have a closed surface circulation from the data I've seen and winds to support a 35 mph TD, if they stay in another hour or 2 , by time they leave we may have TS Richard at 5pm EST, JMO.
agree.
A little convection this evening and we could see a TD tomorrow morning.
Same goes for FLstormwarning, flag him as well.
nope
I'm with you. It seems like it has reached it's intensity minimum and is building convection again.
Currently stationary and happy.
i can't seem to figure this out...all of a sudden...i have this clunky display with just plain text....
And yet look who rears his head defending him.
Odd huh? Not really.
Winds consistently over 20kts for five hours now.
Looking at Google Earth reconnaissance, seems there is a pretty good wind shift and closed circulation..
Transmitted: 19th day of the month at 19:14Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 303)
Mission Purpose: Investigate eight suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 13
A. Time of Center Fix: 19th day of the month at 19:09:00Z
B. Center Fix Coordinates: 17°23'N 83°29'W (17.3833N 83.4833W)
B. Center Fix Location: 191 miles (308 km) to the SW (226°) from George Town, Cayman Islands (GBR).
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 27kts (~ 31.1mph)
E. Location of the Estimated Maximum Surface Wind: 20 nautical miles (23 statute miles) to the NNW (347°) of center fix
F. Maximum Flight Level Wind Inbound: From 112° at 20kts (From the ESE at ~ 23.0mph)
G. Location of Maximum Flight Level Wind Inbound: 21 nautical miles (24 statute miles) to the NNW (347°) of center fix
H. Minimum Sea Level Pressure: 1009mb (29.80 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 22°C (72°F) at a pressure alt. of 303m (994ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 23°C (73°F) at a pressure alt. of 302m (991ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 22°C (72°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Wind and Pressure
N. Fix Level: 1,500 feet
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 5 nautical miles
Remarks Section:
Maximum Flight Level Wind: 20kts (~ 23.0mph) in the north quadrant at 18:59:30Z
Sea Level Pressure Extrapolation From: Below 1,500 feet
You must be prescient !. I was just about to post the data from that buoy. 99L starting to take on a different look now, more aggressive if I might put it that way.
That's the upwelling caused by a recent Tehuano Event, a wind phenomenon (the Tehuantepecer) that can drop SSTs in the area by up to 10.C in a single day...
Click for larger image:
Now we need a confirmation from ATCF and NHC and we are good to go.
1009.2 mb
(~ 29.80 inHg)
30 knots
(~ 34.5 mph)
LOL. Well, you know what they say...
What I have always been concerned about with this system is the potential for a slow crawl close to us then a stall. Over the past couple of days the steering has shown a propensity to collapse over the NW Caribbean in an area of very weak flow between us and the Yucatan.
My thinking was for this to possibly stall out very close to us, sit for some time and then get pushed back to the South by a building ridge of high pressure over the SE CONUS.
We will need to watch the evolution of the steering winds very carefully. October and November are well known for erratic track behaviour from tropical systems in the Caribbean.
NICE! Thank you for the explanation! I saw that one too, and was clueless...
Looking back on my first post, I think the rain alone is enough to cause some issues, just seems like this one may be a real disruption to the CI for a lot of reasons.
Even heavy rain days inflict a lot of economic damage for the duty free stores as the cruise lines have to tender people ashore and who wants to ride a tender from a ship and then walk around in the rain ?.
17Oct 06pmGMT - 12.8n80.4w - 20knots - 1009mb - ATCF*11.6n78.5w*12.3n79.9w*12.5n80.1w
18Oct 12amGMT - 13.3n81.0w - 20knots - 1010mb - *12.6n80.6w*13.1n81.0w*13.4n81.1w*13.4n81.0w
18Oct 06amGMT - 13.7n81.4w - 20knots - 1010mb - ATCF*14.0n81.8w*14.3n81.8w*13.8n81.5w
18Oct 12pmGMT - 14.1n81.8w - 25knots - 1010mb - ATCF*15.1n82.5w*15.0n82.4w*14.1n81.9w
18Oct 06pmGMT - 14.6n82.3w - 25knots - 1010mb - ATCF*15.7n83.2w*14.5n82.2w
19Oct 12amGMT - 15.1n82.7w - 25knots - 1009mb - ATCF*15.0n82.6w
19Oct 06amGMT - 15.8n82.9w - 25knots - 1009mb - ATCF*15.7n83.0w*1008mb
19Oct 12pmGMT - 16.5n83.0w - 25knots - 1009mb - ATCF*16.5n83.3w*1008mb
19Oct 06pmGMT - 17.0n83.0w - 30knots - 1009mb - ATCF
* Before NHC reevaluated&revised the ATCF numbers
Copy&paste 12.8n80.4w, 13.3n81.0w, 13.7n81.4w, 14.1n81.8w, 14.6n82.3w-15.1n82.7w, 15.1n82.7w-15.8n82.9w, 15.8n82.9w-16.5n83.0w, 16.5n83.0w-17.0n83.0w, ctm, cyo into the GreatCircleMapper for a look at the last 24^hours
Viewing: 301 - 351
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