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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1176. KEEPEROFTHEGATE (Mod)
4:06 PM GMT on October 21, 2010
2010 Storms
All Active Year


Atlantic

90L.INVEST
19L.RICHARD

East Pacific

Central Pacific

West Pacific
98W.INVEST
16W.SIXTEEN
15W.MEGI

Indian Ocean
04B.GIRI

Southern Hemisphere

Member Since: July 15, 2006 Posts: 171 Comments: 53841
1175. stillwaiting
3:57 PM GMT on October 21, 2010
Quoting hurricanejunky:


You obviously took the business communication the wrong way and now you're misrepresenting it.

Our stream will be free too just as it always has been.

We'll be streaming live from wherever Richard makes landfall (in the US), how about you?
no,i'm just a amateur doing it for fun and to learn...
Member Since: October 5, 2007 Posts: 20 Comments: 4970
1174. kwgirl
3:41 PM GMT on October 21, 2010
Quoting afj3:
Am I evil to say this but ever since I was a little kid, every time a hurricane brews I want it to hit where I live? I see the models are really changing....
I don't think it is evil, maybe naive. As a kid growing up in the Keys, a hurricane coming our way was great excitement. Even the adults while buying supplies in the store would wish every a "Happy Hurricane". Then Camile came barreling toward us as a Cat 5. Thank God it crossed over Cuba several times, knocking the wind out of her before she hit the keys. And we all know what happened in Biloxi while the people were having a hurricane party. When you have a loss of life and/or property, then you realize how serious these storms get. Put it down to your curiosity. But don't wish it on yourself. Maybe you should go into storm chasing. JMO
Member Since: March 28, 2008 Posts: 0 Comments: 1532
1173. hurricanejunky
3:30 PM GMT on October 21, 2010
Quoting stillwaiting:
IF a tc threatens the west coas of fl i will be streaming live linked thru wunderground.com,IF,...no profits intended,100%free,as im a chaser because its what i love doing..all will be welcomed!!


You obviously took the business communication the wrong way and now you're misrepresenting it.

Our stream will be free too just as it always has been.

We'll be streaming live from wherever Richard makes landfall (in the US), how about you?
Member Since: August 28, 2006 Posts: 6 Comments: 2898
1172. afj3
2:10 PM GMT on October 21, 2010
Quoting NotJFV:

No not evil, just probably have never been thru one.
Believe me it all changes after:
your community has been ripped apart,
you're sweltering in 90 degree heat with out air conditioning,
creature comforts are all gone except for the literal creatures,
insurance payments double,
contractors take over 8 months to fix your roof (if you're lucky),
someone cuts you off at a light because, oh yeah there is no light to stop at,
you scrounge around for water and decide that maybe drinking out of the toilet isn't a bad idea,
you can see the moonlight thru your roof and under an umbrella,
you have to protect your house with a gun because looters might be out to get at the little you have left,
etc.
Yeah, are you sure? OK, enjoy!

I have been through tons of them. Tons. Bad ones, too. I don't wish damage on anyone but just to see what Mother Nature can do whips up some base curiosity in me....
Member Since: June 10, 2008 Posts: 0 Comments: 347
1171. stillwaiting
2:04 PM GMT on October 21, 2010
Quoting reedzone:


Cloud shields are up! Richard could gradually organize more tonight into tomorrow.


The cloud shield protects a storm from entraining dry air into the core. Like I said a few days ago, dry air won't be much of an inhibitor.
....yes it" could",verrry sneaky wording matt(joke)...imo a track into the yucatan is most likely w/no curve to the north(gom),just have to wait and see,i" could" change my thinkng on that,lol...
Member Since: October 5, 2007 Posts: 20 Comments: 4970
1168. reedzone
1:55 PM GMT on October 21, 2010
Quoting cat5hurricane:

No...I do not see dry air impeding his development on the level it affected Paula.


No, I'm not saying you said that, just giving my opinion on the storm as of this morning.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
1167. fmbill
1:54 PM GMT on October 21, 2010
Kind of looks like the COC is trying to reform to the east, under the heavy convection.

Link
Member Since: May 27, 2008 Posts: 0 Comments: 455
1166. Orcasystems
1:54 PM GMT on October 21, 2010
New blog :)
Member Since: October 1, 2007 Posts: 81 Comments: 26511
1164. kmanhurricaneman
1:53 PM GMT on October 21, 2010
r.i on the way
Member Since: August 14, 2008 Posts: 0 Comments: 1002
1163. CyclonicVoyage
1:52 PM GMT on October 21, 2010
Member Since: January 30, 2010 Posts: 0 Comments: 3259
1161. reedzone
1:51 PM GMT on October 21, 2010
Quoting cat5hurricane:
06Z GFS (250MB) 48 hours out gives Richard the green light for the most part to really get itself together. Conditions aloft pretty favorable.



Cloud shields are up! Richard could gradually organize more tonight into tomorrow.


The cloud shield protects a storm from entraining dry air into the core. Like I said a few days ago, dry air won't be much of an inhibitor.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
1158. CyclonicVoyage
1:49 PM GMT on October 21, 2010
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 21st day of the month at 13:45Z
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: 10
A. Time of Center Fix: 21st day of the month at 13:27:20Z
B. Center Fix Coordinates: 16°19'N 80°29'W (16.3167N 80.4833W)
B. Center Fix Location: 215 miles (346 km) to the SSE (164°) from George Town, Cayman Islands (GBR).
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 28kts (~ 32.2mph)
E. Location of the Estimated Maximum Surface Wind: 93 nautical miles (107 statute miles) to the NE (36°) of center fix
F. Maximum Flight Level Wind Inbound: From 130° at 26kts (From the SE at ~ 29.9mph)
G. Location of Maximum Flight Level Wind Inbound: 93 nautical miles (107 statute miles) to the NE (36°) of center fix
H. Minimum Sea Level Pressure: 1007mb (29.74 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 22°C (72°F) at a pressure alt. of 431m (1,414ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 23°C (73°F) at a pressure alt. of 429m (1,407ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 21°C (70°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 Levels (sfc and flt lvl centers are within 5nm of each other): Surface and 1,500 feet
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 5 nautical miles
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 40kts (~ 46.0mph) in the east quadrant at 12:25:00Z
Sea Level Pressure Extrapolation From: Below 1,500 feet
Maximum Flight Level Temp: 24°C (75°F) which was observed 36 nautical miles (41 statute miles) to the NNE (25°) from the flight level center
Remarks Section - Additional Remarks...
Convection East Quad
Max SWS 37kts east quad 12:25:35Z
Member Since: January 30, 2010 Posts: 0 Comments: 3259
1157. nrtiwlnvragn
1:48 PM GMT on October 21, 2010
GOES East is in rapid scan mode (8 images per hour) today. GHCC loop
Member Since: September 23, 2005 Posts: 14 Comments: 11179
1156. scott39
1:48 PM GMT on October 21, 2010
NHC has Richard on thier Floater. It also looks like hes moving due S.
Member Since: June 13, 2009 Posts: 0 Comments: 6784
1154. Orcasystems
1:47 PM GMT on October 21, 2010
Complete Update

HH data and the new 90L



AOI
AOI AOI AOI

AOI AOI AOI

TS BUSTED FORECAST ALIBI
Member Since: October 1, 2007 Posts: 81 Comments: 26511
1153. CaicosRetiredSailor
1:46 PM GMT on October 21, 2010
Member Since: July 12, 2007 Posts: 0 Comments: 6037
1152. robert88
1:45 PM GMT on October 21, 2010
Basically what it comes down to is the faster Richard moves the better chance it will not deal with as much shear and could impact FL as a strong TS or hurricane. If the ECMWF is correct on the timing it will get smacked with strong shear and will end up a remnant LP.
Member Since: May 22, 2010 Posts: 0 Comments: 907
1151. stillwaiting
1:44 PM GMT on October 21, 2010
Quoting cat5hurricane:

Look fwd to that. Not the cane heading to FL, but to see that live steam. Very cool man. Just be careful
...notice the word" if" in bold letters twice,i'm still highly suspect of a cane forecast to make landfall in my area,because we always get tye threat,but never the landfall,so i doubt it until its imenent tomany false alarms to gt workd uo yet,jmo
Member Since: October 5, 2007 Posts: 20 Comments: 4970
1150. kmanhurricaneman
1:44 PM GMT on October 21, 2010
coc 16.0 80.2
Member Since: August 14, 2008 Posts: 0 Comments: 1002
1149. LightningCharmer
1:44 PM GMT on October 21, 2010
Quoting NotJFV:

No not evil, just probably have never been thru one.
Believe me it all changes after:
your community has been ripped apart,
you're sweltering in 90 degree heat with out air conditioning,
creature comforts are all gone except for the literal creatures,
insurance payments double,
contractors take over 8 months to fix your roof (if you're lucky),
someone cuts you off at a light because, oh yeah there is no light to stop at,
you scrounge around for water and decide that maybe drinking out of the toilet isn't a bad idea,
you can see the moonlight thru your roof and under an umbrella,
you have to protect your house with a gun because looters might be out to get at the little you have left,
etc.
Yeah, are you sure? OK, enjoy!
Brings back memories...a little humor here but mostly reality. Good post.
Member Since: September 1, 2007 Posts: 0 Comments: 1316
1147. Grothar
1:42 PM GMT on October 21, 2010
Quoting Abacosurf:
LMAO. Now can you put Nixon there....


Sorry, that's too "Tricky"
Member Since: July 17, 2009 Posts: 71 Comments: 26151
1146. kwgirl
1:41 PM GMT on October 21, 2010
Quoting CyclonicVoyage:



I would like that. Hopefully, if Richard decides to pay a visit, he will have had too many Cerveza's in the Yucatan.
Good morning everyone. This is all we need! A drunk storm that meanders all over the place. Then no one will be able to tell where it is going!LOL
Member Since: March 28, 2008 Posts: 0 Comments: 1532
1143. IceSlater
1:40 PM GMT on October 21, 2010
Navy site has TS Richard
Member Since: July 6, 2005 Posts: 0 Comments: 417
1142. Grothar
1:40 PM GMT on October 21, 2010
Quoting OracleDeAtlantis:


Best laugh of the day .... so far.


Got to calm people down sometime with a little levity. Glad you got a chuckle.
Member Since: July 17, 2009 Posts: 71 Comments: 26151
1141. CyclonicVoyage
1:40 PM GMT on October 21, 2010
Quoting Jeff9641:


What's going on?


Looks like they are trying to locate the center.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
1140. Abacosurf
1:39 PM GMT on October 21, 2010
Quoting Grothar:


Come on Sammy, I told you before, don't get excited until you see something like this.

LMAO. Now can you put Nixon there....
Member Since: August 28, 2008 Posts: 0 Comments: 366
1139. HadesGodWyvern (Mod)
1:39 PM GMT on October 21, 2010


Cyclonic Storm Giri
Member Since: May 24, 2006 Posts: 51 Comments: 45308
1136. caneswatch
1:36 PM GMT on October 21, 2010
Quoting Grothar:


Told you so, told you so! How you doing Canes?

Just make sure you are all stocked up on batteries, water and Cheese Doodles. You should be OK.


I was saying it too lol. No hurricane experience should be without beef jerky for me either. I'll be stocking up on what you said, including some Mr. Pibb, Cool Ranch Doritos, and some salsa con queso.
Member Since: October 8, 2008 Posts: 14 Comments: 4553
1135. HadesGodWyvern (Mod)
1:35 PM GMT on October 21, 2010
AL, 19, 2010102112, , BEST, 0, 165N, 807W, 35, 1006, TS

Tropical Cyclone "RICHARD"
Member Since: May 24, 2006 Posts: 51 Comments: 45308
1134. NotJFV
1:35 PM GMT on October 21, 2010
Quoting afj3:
Am I evil to say this but ever since I was a little kid, every time a hurricane brews I want it to hit where I live? I see the models are really changing....

No not evil, just probably have never been thru one.
Believe me it all changes after:
your community has been ripped apart,
you're sweltering in 90 degree heat with out air conditioning,
creature comforts are all gone except for the literal creatures,
insurance payments double,
contractors take over 8 months to fix your roof (if you're lucky),
someone cuts you off at a light because, oh yeah there is no light to stop at,
you scrounge around for water and decide that maybe drinking out of the toilet isn't a bad idea,
you can see the moonlight thru your roof and under an umbrella,
you have to protect your house with a gun because looters might be out to get at the little you have left,
etc.
Yeah, are you sure? OK, enjoy!
Member Since: August 6, 2010 Posts: 0 Comments: 71
1133. CyclonicVoyage
1:34 PM GMT on October 21, 2010
Everyone forget about recon?

13:22:00Z 16.567N 80.367W 962.7 mb
(~ 28.43 inHg) 402 meters
(~ 1,319 feet) 1007.7 mb
(~ 29.76 inHg)
Member Since: January 30, 2010 Posts: 0 Comments: 3259
1132. OracleDeAtlantis
1:33 PM GMT on October 21, 2010
Quoting Grothar:


Come on Sammy, I told you before, don't get excited until you see something like this.



Best laugh of the day .... so far.
Member Since: August 27, 2009 Posts: 0 Comments: 524
1131. Grothar
1:32 PM GMT on October 21, 2010
Quoting caneswatch:


Hahahaha. Good morning Grothar and everyone else. I see that the models have taken a very dramatic shift. This is getting scarier by the moment.


Told you so, told you so! How you doing Canes?

Just make sure you are all stocked up on batteries, water and Cheese Doodles. You should be OK.
Member Since: July 17, 2009 Posts: 71 Comments: 26151
1129. Chicklit
1:30 PM GMT on October 21, 2010
Thanks for the info Skye.
We could sure use the rain.
Member Since: July 11, 2006 Posts: 14 Comments: 11328
1128. stillwaiting
1:29 PM GMT on October 21, 2010
IF a tc threatens the west coas of fl i will be streaming live linked thru wunderground.com,IF,...no profits intended,100%free,as im a chaser because its what i love doing..all will be welcomed!!
Member Since: October 5, 2007 Posts: 20 Comments: 4970
1127. RitaEvac
1:29 PM GMT on October 21, 2010
FAT cone

Member Since: July 14, 2008 Posts: 1 Comments: 9630
1126. afj3
1:28 PM GMT on October 21, 2010
Am I evil to say this but ever since I was a little kid, every time a hurricane brews I want it to hit where I live? I see the models are really changing....
Member Since: June 10, 2008 Posts: 0 Comments: 347

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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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