Little change to 99L, which remains very close to tropical depression status

By: Dr. Jeff Masters , 7:11 PM GMT on October 20, 2010

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A tropical disturbance (Invest 99L) centered 160 miles southwest of the Cayman Islands is moving south to southeast at 5 - 10 mph. A Hurricane Hunter flight arrived in the storm at about 11am this morning, and found a closed circulation with top winds at flight level (700 feet) of 33 mph. A closed circulation and 30 mph surface winds are necessary conditions for a tropical depression to exist, but the storm must also have a great deal of heavy thunderstorm activity near the center that persists for many hours. In the judgment of NHC, 99L does not qualify as a tropical depression in that regard. The storm is bringing heavy rain to the Cayman Islands; 4.14" inches has fallen over the past 2 1/2 days at Savannah on Grand Cayman Island. Heavy rains have diminished over the Cayman Islands, but have spread to western Jamaica and west-central Cuba this afternoon. Recent satellite imagery shows that the surface circulation center is exposed to view, and 99L has a relatively meager amount of heavy thunderstorm activity. The center is more than 80 miles west of the heaviest thunderstorm activity, and it is likely that 99L's center will relocate itself to the east to be more underneath the heaviest thunderstorms. Wind shear is marginal for development, 15 - 20 knots, due to the clockwise flow of air around an upper-level high pressure system near the coast of Honduras. The high is bringing strong upper-level winds out of the southwest to 99L. Water vapor satellite loops show considerable dry air to the west and north of 99L, and the strong southwesterly winds over the storm are bringing some of this dry into into the core of the storm, keeping all the heavy thunderstorm development confined to the east side of the center. The waters beneath 99L are very warm, 29°C, but 99L will not be able to take advantage of these warm waters until the shear relaxes. A new hurricane hunter aircraft will be in the storm tonight near 8pm EDT.

Forecast for 99L
The current southward movement of 99L is carrying the storm into a region of lower wind shear, and we should see 99L accumulate more heavy thunderstorm activity near its center beginning tonight. The latest SHIPS model forecast predicts that wind shear over the Western Caribbean will decline below 15 knots Thursday afternoon through Saturday afternoon, which should allow the storm to become a tropical depression by Thursday. Steering currents will be weak today through Friday in the Western Caribbean, making it difficult to predict where 99L may go. The models are split into two camps, with the GFDL and HWRF models taking 99L to the west-northwest over the western tip of Cuba or the Yucatan Peninsula on Sunday as a hurricane. The rest of the models take 99L to the south over Honduras on Sunday, and keep the storm below hurricane strength. Given 99L's current southward motion and the possibility that the center will relocate farther to the east later today, this makes a track to the southwest towards Honduras more likely, I predict. NHC is giving 99L a 70% chance of developing into a tropical depression by Friday, which is a reasonable forecast. I expect this will become Tropical Storm Richard by Friday.


Figure 1. Afternoon satellite image of Invest 99L.

Death toll from Super Typhoon Megi in the Philippines remarkably low
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 full extent of the destruction wrought by the great storm is still unclear. However, the death toll from the great storm stands at only 19, reflecting the superior effort Philippines officials made to evacuate low-lying areas and get people out of locations prone to flash flooding and mudslides. Previous major typhoons to strike the Philippines have nearly always killed hundreds, and sometime thousands, so the preparation and evacuation efforts for Megi likely saved hundreds of lives. 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. Severe damage was done to Isabela Province in northern Luzon, and media reports indicate that 200,000 people are homeless.


Figure 2. Visible MODIS satellite image of Megi from NASA's Aqua satellite taken at 1:30am EDT October 20, 2010. At the time, Megi was a Category 4 typhoon with 135 mph winds. Image credit: NASA.

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 intensified into a formidable Category 3 typhoon with 125 mph winds. 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 remain a very dangerous major typhoon through Friday. 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 north of 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, or as a strong Category 2, bringing a significant storm surge, high winds, and widespread torrential rains that will likely make this a multi-billion dollar disaster for China. The outer rain bands of Megi are already affecting the coast of China north of Hong Kong, as seen on Hong Kong radar and Taiwan radar.


Figure 3. Still frame of damage to NE Luzon Island from a video posted to YouTube by storm chaser James Reynolds of typhoonfury.com.

Next update
I'll have an update Thursday morning.

Jeff Masters

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Thanks, see it on Graphical forecast now...lol, WAKE UP Erich....lol

Quoting stormwatcherCI:
NHC gives it a 10% chance of development.
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Quoting PensacolaDoug:



Sometimes. We know the NHC/TPC has been taken by surprise many times in the last few years.
Seems they were not going to let that happen with this one. Thats why they started flying into this one two days ago, I'm thinking. No more surprises for them!
The funny thing here in Cayman is that our weather service gave the last update at 10 PM(11 PM EDT) last night and said the next update would be at 5 AM local time and nothing still.
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Quoting kmanhurricaneman:
are we that good that we can announce a storm name before NHC



Sometimes. We know the NHC/TPC has been taken by surprise many times in the last few years.
Seems they were not going to let that happen with this one. Thats why they started flying into this one two days ago, I'm thinking. No more surprises for them!
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Quoting Goldenblack:
I am confirming that at the moment on the ATCF site....

but has anyone seen this? (sorry, been drinking coffee, have not looked back yet).

BEGIN
NHC_ATCF
invest_al902010.invest
FSTDA
R
U
040
010
0000
201010211211
NONE
NOTIFY=ATRP
END
INVEST, AL, L, , , , , 90, 2010, DB, O, 2010102112, 9999999999, , , , , , METWATCH, , AL902010
AL, 90, 2010102012, , BEST, 0, 96N, 185W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102018, , BEST, 0, 97N, 195W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102100, , BEST, 0, 98N, 205W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102106, , BEST, 0, 99N, 215W, 20, 1010, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102112, , BEST, 0, 100N, 225W, 20, 1010, LO, 34, NEQ, 0, 0, 0, 0, 1012, 200, 90, 0, 0, L, 0, , 0, 0, INVEST, D,


NHC gives it a 10% chance of development.
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Quoting Goldenblack:
I am confirming that at the moment on the ATCF site....

but has anyone seen this? (sorry, been drinking coffee, have not looked back yet).

BEGIN
NHC_ATCF
invest_al902010.invest
FSTDA
R
U
040
010
0000
201010211211
NONE
NOTIFY=ATRP
END
INVEST, AL, L, , , , , 90, 2010, DB, O, 2010102112, 9999999999, , , , , , METWATCH, , AL902010
AL, 90, 2010102012, , BEST, 0, 96N, 185W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102018, , BEST, 0, 97N, 195W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102100, , BEST, 0, 98N, 205W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102106, , BEST, 0, 99N, 215W, 20, 1010, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102112, , BEST, 0, 100N, 225W, 20, 1010, LO, 34, NEQ, 0, 0, 0, 0, 1012, 200, 90, 0, 0, L, 0, , 0, 0, INVEST, D,




Very cool: Soon-to-be-Richard, and a new invest in the far eastern Atlantic.

Gonna be a busy day here...
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When we have a direct link to ATCF, yes, we can act like we are mind readers.....lol


Quoting kmanhurricaneman:
are we that good that we can announce a storm name before NHC
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<
Quoting Jeff9641:
WE have RICHARD


What national weather service has called it ??
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Seems we do have a rename in progress.....

BEGIN
NHC_ATCF
invest_RENUMBER_al992010_al192010.ren
FSTDA
R
U
040
010
0000
201010210043
NONE
NOTIFY=ATRP
END


Quoting Goldenblack:
I am confirming that at the moment on the ATCF site....

but has anyone seen this? (sorry, been drinking coffee, have not looked back yet).

BEGIN
NHC_ATCF
invest_al902010.invest
FSTDA
R
U
040
010
0000
201010211211
NONE
NOTIFY=ATRP
END
INVEST, AL, L, , , , , 90, 2010, DB, O, 2010102112, 9999999999, , , , , , METWATCH, , AL902010
AL, 90, 2010102012, , BEST, 0, 96N, 185W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102018, , BEST, 0, 97N, 195W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102100, , BEST, 0, 98N, 205W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102106, , BEST, 0, 99N, 215W, 20, 1010, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102112, , BEST, 0, 100N, 225W, 20, 1010, LO, 34, NEQ, 0, 0, 0, 0, 1012, 200, 90, 0, 0, L, 0, , 0, 0, INVEST, D,


Member Since: Posts: Comments:
I am confirming that at the moment on the ATCF site....

but has anyone seen this? (sorry, been drinking coffee, have not looked back yet).

BEGIN
NHC_ATCF
invest_al902010.invest
FSTDA
R
U
040
010
0000
201010211211
NONE
NOTIFY=ATRP
END
INVEST, AL, L, , , , , 90, 2010, DB, O, 2010102112, 9999999999, , , , , , METWATCH, , AL902010
AL, 90, 2010102012, , BEST, 0, 96N, 185W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102018, , BEST, 0, 97N, 195W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102100, , BEST, 0, 98N, 205W, 15, 1011, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102106, , BEST, 0, 99N, 215W, 20, 1010, LO, 34, NEQ, 0, 0, 0, 0, 850, 0, 0, 0, 0,
AL, 90, 2010102112, , BEST, 0, 100N, 225W, 20, 1010, LO, 34, NEQ, 0, 0, 0, 0, 1012, 200, 90, 0, 0, L, 0, , 0, 0, INVEST, D,


Quoting Jeff9641:
WE have RICHARD
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flash loop final shot shows beginning of sunrise...good time to look into it...15 min more and we shall see it all.


Link
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are we that good that we can announce a storm name before NHC
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Quoting SweetHomeBamaGOM:



heck the real problem has been the lack of rain for months. it's bone dry here all across the panhandle clear into n.o..
I feel for you. It was that way back in 2006 and 2007 in south Florida. I had never seen Lake Okeechobee so low. I know before everyone jumps on this, some of the low lake condition was due to questionable draining in preparation of a high seasonal rain forecast that never materialized.
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Oz gonna have somethin to chase!
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955. IKE
Quoting cat5hurricane:

That's what it's looking like. Are they still on the 6 hour interval in regards to the advisories?


Yes.
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All I have to say about Megi is:

1. Wow
2. Wow wow
3. Hong Kong should be counting their blessings that they are not getting this monster.



On another note: How long now has the Philippines had to deal with this thing!? It is still close by
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Quoting wunderkidcayman:
11:43:00Z 16.050N 80.217W 962.6 mb
(~ 28.43 inHg) 397 meters
(~ 1,302 feet) 1007.7 mb
(~ 29.76 inHg) - From 224° at 20 knots
(From the SW at ~ 23.0 mph) 19.7°C
(~ 67.5°F) 18.1°C
(~ 64.6°F) 20 knots
(~ 23.0 mph) 40 knots
(~ 46.0 mph) 16 mm/hr
(~ 0.63 in/hr) 40.0 knots (~ 46.0 mph)
Tropical Storm 200.0%



I guess we have TS Richard


Don't tell ike
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i have been up from early checking and checking and frankly i have to agree with GDFL,HWRF AND NAM models cayman get ready we about to get a good blow in a couple of days.
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Mini Update on TD #19
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Jeff, I have to hand it to you, you have stuck to your guns, and now it seems the NHC is beginning to believe the same in what they are seeing/trending:

I HAVE LESS CONFIDENCE IN THE FORECAST BEYOND 72 HOURS
BECAUSE THE GFDL...THE HWRF AND THE ECMWF TURN THE CYCLONE TOWARD
THE NORTH OVER THE YUCATAN CHANNEL AND THE SOUTHEASTERN GULF OF
MEXICO. I WOULD NOT BE SURPRISED IF THE TRACK HAS TO BE ADJUSTED
NORTHWARD LATER ON.


Quoting Jeff9641:


A hurricane coming trough here next week could easily dump 8 to 15" of rain early next week. I am like our chances now of getting a good storm in C FL. Quite a few models in the FL camp right now and they have stayed that for for the last couple of days.
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11:43:00Z 16.050N 80.217W 962.6 mb
(~ 28.43 inHg) 397 meters
(~ 1,302 feet) 1007.7 mb
(~ 29.76 inHg) - From 224° at 20 knots
(From the SW at ~ 23.0 mph) 19.7°C
(~ 67.5°F) 18.1°C
(~ 64.6°F) 20 knots
(~ 23.0 mph) 40 knots
(~ 46.0 mph) 16 mm/hr
(~ 0.63 in/hr) 40.0 knots (~ 46.0 mph)
Tropical Storm 200.0%



I guess we have TS Richard
Member Since: June 13, 2009 Posts: 2 Comments: 12712
944. IKE
Looks like TD19 stays a TD for now. Winds near 30 mph...pressure 1006 mb's...moving south.
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872 aislinnpaps "If I had a water gauge it'd be full of sand and dust. The fire in the National Forest next to me is 60% contained. We need rain!"

Well, from the massive number of complaints on here about his downcasting, we all know who to blame. Apparently all IKE hasta do is insist that a hurricane ain't gonna hit the Gulf states, and tropical cyclones skeedaddle off to do their rain of terror elsewhere.
Probably uses a HAARP or somethin' while pretendin' to be "just delivering the news."
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939. IKE
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 21st day of the month at 11:47Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 309)
Tropical Depression: Number 19 (flight in the North Atlantic basin)
Mission Number: 3
Observation Number: 07
A. Time of Center Fix: 21st day of the month at 11:30:00Z
B. Center Fix Coordinates: 16°33'N 80°42'W (16.55N 80.7W) (View map)
B. Center Fix Location: 196 miles (315 km) to the SSE (167°) from George Town, Cayman Islands (GBR).
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 24kts (~ 27.6mph)
E. Location of the Estimated Maximum Surface Wind: 63 nautical miles (72 statute miles) to the NNW (334°) of center fix
F. Maximum Flight Level Wind Inbound: From 55° at 26kts (From the NE at ~ 29.9mph)
G. Location of Maximum Flight Level Wind Inbound: 66 nautical miles (76 statute miles) to the NNW (334°) of center fix
H. Minimum Sea Level Pressure: 1006mb (29.71 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 23°C (73°F) at a pressure alt. of 427m (1,401ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 23°C (73°F) at a pressure alt. of 427m (1,401ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 19°C (66°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: 26kts (~ 29.9mph) in the northwest quadrant at 11:08:40Z
Sea Level Pressure Extrapolation From: Below 1,500 feet
Maximum Flight Level Temp: 24°C (75°F) which was observed 6 nautical miles to the NW (323°) from the flight level center
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Quoting cat5hurricane:
Florida's total precipitation amounts for the last 14 days.



heck the real problem has been the lack of rain for months. it's bone dry here all across the panhandle clear into n.o..
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It is quite amazing how much dry air is there Chicklit...

NHC and NWS both predict that trough, whose base is sitting just above that dry air, will begin lifting NE today and the High Pressure will build in behind over the next couple days and ventilate that moisture back to the north of TD19.

We'll see if it happens that way.

Quoting Chicklit:
Hi Goodmorning,


Look at all that dry air!
WVLoop
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Quoting cat5hurricane:
Florida's total precipitation amounts for the last 14 days.
Mobile is the rainest city in the US and we are going to dry up and blow away soon!
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Hi Goodmorning,


Look at all that dry air!
WVLoop
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Quoting stormpetrol:
890. stormwatcherCI
Good morning all,I personally think that at 7am Local we should be under a TS warning just in case,quite possibly a hurricane watch also, just my opinion though!
I tend to agree that when a system is this close to land, and even has a slight potential to strike why not issue a tropical storm watch. Of course by declaring such, tourist based businesses will cry fowl, and various governmental agencies that are required to act when a watch or warning is issued will claim precious tax payer money is being wasted, and they do have a point. I guess it's always a balance between safety and awareness as opposed to economics both commercial and governmental. I haven't even mentioned the way insurance is settled depending on whether it's a named storm or not so then we're adding politics into the mix.

Admittedly, I don't really know the exact criteria for issuing watches and warnings that is used but I'm sure it's more than a matter of opinion between a few meteorologist, and I would hope that it is almost entirely based on human safety and limiting property damage.
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Quoting SweetHomeBamaGOM:


ty. i am reading too fast as i am also flipping between internet tabs watching loops and models. lol my fault sorry but ty for the graphic, it's useful to everyone :)
We all do it at times. LOL
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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