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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1026. IKE
Quoting GeoffreyWPB:
AL, 19, 2010102112, , BEST, 0, 165N, 807W, 35, 1006, TS


I saw this...just upgraded....

Information About Tropical Storm Richard

Storm information valid as of: Thursday, October 21, 2010 12:00 Z
Coordinates: 16.5N 80.7W (View Map or View Storm Centered Satellite Image)
Location: 199 miles (320 km) to the SSE (167°) from George Town, Cayman Islands (GBR)
Distance Calculator: How far away is this storm from me?
Pressure (MSLP): 1006 mb (29.71 inHg | 1006 hPa)
Sustained wind speed (1 min. avg.): 35 knots (40 mph | 18 m/s)
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king richard has arrived. ty nea for the update.

we will see what kind of a crusade he has planned next....lol
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Complete Update



AOI
AOI AOI AOI

AOI AOI AOI

TS BUSTED FORECAST ALIBI
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Now it's really official, with a name and everything...

AL, 19, 2010102112, , BEST, 0, 165N, 807W, 35, 1006, TS, 34, NEQ, 90, 90, 0, 0, 1010, 200, 80, 0, 0, L, 0, , 0, 0, RICHARD, S,
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1021. WxLogic
A Special Advisory might be issue to announce the newly developed TS Richard, since we're no near close to 11AM EST.
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1018. scott39
When is the trough forecasted to influence Richards stearing when and if he gets in the GOM?
Member Since: June 13, 2009 Posts: 0 Comments: 6732
Quoting SweetHomeBamaGOM:



so have they announced t.s. status at nhc?
no they havent as to time of this post
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1016. NotJFV
THE OFFICIAL TRACK FORECAST HAS SHIFTED A LITTLE BIT TO
THE NORTH...AND IS HEAVILY BASED ON THE GFS...THE UK MODELS AND
CONTINUITY. 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.


The NHC has definitely given themselves an "out" to change the cone north. I think they're waiting for recon and then they'll figure out how the new "Cone of uncertainty" sets up.

Disclaimer, I am a complete novice but thus is what I have gathered so far.
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Quoting GeoffreyWPB:
AL, 19, 2010102112, , BEST, 0, 165N, 807W, 35, 1006, TS



so have they announced t.s. status at nhc?
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1013. scott39
Quoting weaverwxman:
I know you really meant to say if Richard makes landfall in US
Ok, If it makes it into the GOM, some form of it landing in the US is too soon!
Member Since: June 13, 2009 Posts: 0 Comments: 6732
AL, 19, 2010102112, , BEST, 0, 165N, 807W, 35, 1006, TS
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Quoting scott39:
I think its too soon to say where Richard is going to make landfall in the US.
I know you really meant to say if Richard makes landfall in US
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1008. afj3
Quoting scott39:
I think its too soon to say where Richard is going to make landfall in the US.

Or if it makes landfall as something of any note?
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1006. scott39
Quoting Jeff9641:


That's because of the trough moving in and forcing a faster movement to the NE. It is appearing that this is our first major threat to the US so far this year.
I think its too soon to say where Richard is going to make landfall in the US.
Member Since: June 13, 2009 Posts: 0 Comments: 6732
1005. whadat
Link
Station 42057. Good Morning.
Member Since: September 8, 2010 Posts: 0 Comments: 33
Quoting Chicklit:
What does GFDL say about little richard?


It's latest model run, along with the hwrf (which has be consistant) have it move through the Yuc. Penn and into the gulf, onto West Coast FL.
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1001. scott39
Who said we have Richard??
Member Since: June 13, 2009 Posts: 0 Comments: 6732
When a system is weak and forecast to go nowhere in a hurry it would be crazy to start issuing a lot of warnings, put yourself in the position of all the people in the tourist industry.I know I'd cancel a lot of my plans if I didn't know much about these systems. Please leave it to the professionals that have done an excellent job this season so far in not over hyping.
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banding is definitely organizing more convection through all quads. he is certainly enjoying the shear sliding north away from the sw quad.
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The GFDL and the HWRF have Richard moving faster than the EURO. We will see!
Member Since: June 13, 2009 Posts: 0 Comments: 6732
Recon's finding lots and lots of TS-force winds now around 16.0N /79.2 (some up to 55 mph).
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Quoting BanTech:
Yes...I have arrived!
LMAO!!! Finally!!!
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AL, 19, 2010102112, , BEST, 0, 165N, 807W, 30, 1006, TD
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Quoting cat5hurricane:

That's the money shot



now i feel like i have been exploited....j.k lol
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Watch what the EURO does in the next few runs!
Member Since: June 13, 2009 Posts: 0 Comments: 6732
What does GFDL say about little richard?
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reminds me of....


Rush--"Force 10"

full sunlit view of 99L (last frame)

Link
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I concur....little more real this morning than yesterday.

Quoting pioggiasuper:


I hope you are wrong again Jeff :)
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Quoting stormwatcherCI:
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.
if you can remember they did the same thing in 2008 paloma
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Saw a couple in 2005 I believe.....but very rare this late. Certainly evidence to the downcasters who said 2010 would be a bust.

It is evident now that the pattern forecasters were seeing for late season were right on the money, awesome.

Quoting Jeff9641:


A CV storm? I've never seen an invest near the CV in late October have you guys as I'm not as old?
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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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