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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1126. 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....
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Quoting Grothar:


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



LOL, Nice.
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Quoting Grothar:


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



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.
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1121. hulakai
climatologicly October TS within 50 km of 16.5 and -80.7 Central Am 17% N. Gulf 17% Fla 42% and Bahamas 25% Fla had 2 cat 3 hits and one cat 3 brush and 2 cat 2 hits. Most recently, Wilma Cat 3 2005.

Not happy with odds. Antennae up!
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Quoting PensacolaDoug:




We chase 'em when presented. About the other, friends is friends but business is business. Sucks, I know. It wasn't done lightly.
...shows true colors,money trumps friendships,rather know sooner than later anyways,glad i never wasted to much time w/the hillbillies,lol
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1119. Grothar
Quoting sammywammybamy:


Wilma...


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

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1118. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #5
TROPICAL DEPRESSION 19
21:00 PM JST October 21 2010
=================================

SUBJECT: Tropical Depression Near Minami Torisima

At 12:00 PM UTC, Tropical Depression (1006 hPa) located at 20.3N 157.2E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The depression is reported as moving west northwest at 13 knots

Dvorak Intensity: T1.5

Forecast and Intensity
=======================
24 HRS: 23.3N 154.8E - 35 knots (CAT 1/Tropical Storm)
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TropicalStormRichard's heading had turned southward to dueSouth
from its previous heading of (3.2degrees east of) SouthSouthEast
TS.Richard's average speed moving between its last 2 reported positions increased to ~11.3mph(~18.2km/h) from its previous moving speed of ~5mph(~8km/h)
Invest 99L
20Oct 12amGMT - 17.7n83.2w - 30knots - 1009mb - ATCF*17.6n83.4w
20Oct 06amGMT - 17.8n82.9w - 30knots - 1008mb - ATCF
20Oct 12pmGMT - 17.7n82.5w - 30knots - 1008mb - ATCF*1007mb
20Oct 06pmGMT - 17.6n81.7w - 30knots - 1008mb - ATCF*17.1n82.2w*17.6n81.6w
TropicalDepression19
21Oct 12amGMT - 17.5n81.2w - 30knots(~55.6km/h) - 1006mb - ATCF*17.6n81.2w
21Oct 03amGMT - 17.5n81.1w - 35mph (~56.3km/h) _ 1006mb - NHC.Adv.#1
21Oct 06amGMT - 17.2n80.8w - 30knots(~55.6km/h) - 1006mb - ATCF*17.3n80.9w*1005mb
21Oct 09amGMT - 17.0n80.7w - 35mph (~56.3km/h) _ 1005mb - NHC.Adv.#2
TropicalStormRichard
21Oct 12pmGMT - 16.5n80.7w - 35knots(~64.8km/h) - 1006mb - ATCF*30knots
* Before NHC reevaluated&revised the ATCF numbers. Also see comment993.

Copy&paste 17.7n83.2w, 17.8n82.9w, 17.7n82.5w, 17.6n81.7w, 17.5n81.2w-17.5n81.1w, 17.5n81.1w-17.2n80.8w, 17.2n80.8w-17.0n80.7w, 17.0n80.7w-16.5n80.7w, rtb, puz, nbw into the GreatCircleMapper for a look at the last 12^hours
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1114. Grothar
Quoting Floodman:


Yep, I've been watching the dynamics for a last couple of phases...looking like more consensus along those lines.

What are we seeing by way of the steering mean?

Good morning, by the way...I was just singing the Pre-Cambrian Tech fight song...do you remember it? LOL


Twit!! Yes, I remember it well.
The steering currents will remain weak for at least 24 to 36 hours. Then the high over the Gulf should retreat to the North and allow a more Norther movement of the system. I believe it will be a trough that MIGHT move Little Richard more to the NE.
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1113. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #11
TROPICAL DEPRESSION 18
21:00 PM JST October 21 2010
=================================

SUBJECT: Tropical Depression Near The Marianas

At 12:00 PM UTC, Tropical Depression (1002 hPa) located at 17.2N 141.2E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The depression is reported as moving west at 11 knots

Dvorak Intensity: T1.5

Forecast and Intensity
=======================
24 HRS: 17.3N 137.4E - 35 knots (CAT 1/Tropical Storm)
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1112. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #67
TYPHOON MEGI (T1013)
21:00 PM JST October 21 2010
=================================

SUBJECT: Category Four Typhoon In South China Sea

At 12:00 PM UTC, Typhoon Megi (935 hPa) located at 20.2N 117.9E has 10 minute sustained winds of 95 knots with gusts of 135 knots. The cyclone is reported as moving northeast slowly

Dvorak Intensity: T6.0

Storm Force Winds
=================
120 NM from the center

Gale Force Winds
=================
240 NM from the center

Forecast and Intensity
=======================
24 HRS: 21.6N 118.0E - 85 knots (CAT 4/Strong Typhoon)
48 HRS: 23.4N 117.7E - 75 knots (CAT 3/Typhoon)
72 HRS: 24.6N 116.9E - 45 knots (CAT 1/Tropical Storm)
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1110. HadesGodWyvern (Mod)
India Meteorological Department
Tropical Cyclone Bulletin #6
CYCLONIC STORM GIRI (BOB04-2010)
14:30 PM IST October 21 2010
====================================

At 9:00 AM UTC, Cyclonic Storm Giri lays centered over the same area near 17.5N 91.5E, or about 350 kms south southwest of Sittwe, Myanmar, 450 kms south of Cox Bazar, Bangladesh, and 650 kms southeast of Digha, West Bengal.

The current environmental conditions and numerical weather prediction models suggest that the system would intensify further into a severe cyclonic storm. It would move northwards initially and then north-northeastwards and cross north Myanmar and adjoining Bangladesh coasts by tomorrow evening between Teknaf, Bangladesh and Kyaukpyu, Myanmar near Sittwe Myanmar.

3 minute sustained winds near the center is 40 knots with gust of 50 knots. The central pressure of the system is 996 hPa. The state of the sea is high around the system's center.

Satellite imagery indicates banding pattern with further organization. The Dvorak intensity is T2.5. Associated broken intense to very intense convection is seen over east central Bay of Bengal between 14.0N to 20.0N and east of 88.0E. The lowest cloud top temperature due to convection is around -80C.

Vertical wind shear of horizontal wind over the region is low to moderate. 24 hours tendency of vertical wind shear shows no significant change. Sea surface temperature is 28-32C and the ocean heat content over central Bay of Bengal are favorable for intensification. However, Ocean heat content is less than 100 kj/cm2. The relative vorticity at 850 hPa level and upper level divergence around the system's center is also favorable for intensification. The system lies close to the south of tropospheric ridge, which roughly runs along 18.0N at 200 HPA level. There is an anticyclonic circulation over central India to the northwest at mid-tropospheric level and is expected to influence the movement of GIRI towards the northeast direction.

Forecast and Intensity
======================
6 HRS: 18.0N 92.0E - 45 knots (Cyclonic Storm)
12 HRS: 18.5N 92.5E - 50 knots (Severe Cyclonic Storm)
24 HRS: 19.5N 93.5E - 60 knots (Severe Cyclonic Storm)
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1109. Jax82
I wouldnt get too excited about where its going until the 5 day cone (which still can have an error up to 300+ miles) hits the U.S. Most of us know how often these models see saw back and forth.

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If Richard can take a path like the GFDL and HWRF are showing looks like there could be a window of less shear off the SW coast of FL and could be a hurricane at landfall. If it goes into the central gulf it will get sheared apart into a rain shower where the bulk of the shear will be present. The crazy thing is if the storm does go into the direction of SW FL the GFS nailed this scenario almost 2 weeks ago. If that happens it makes you wonder why it dropped the ball. It has been clearly the best model for sniffing out development and sometimes gets the long range tracks close 7-10 days in advance with the early runs. When the storm actually starts to form or just before it seems to change it's mind and go another route. That is the only major con i have seen with the GFS since the upgrade this season.
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1106. Skyepony (Mod)
As for Richard our top two performers eventually hit SouthWest Florida..one to watch..
Average Position Error (nm) for core models
model Error Trend 24hr Error 48hr Error 72hr Error Day 4 Error Day 5 Error
HWRF DECREASING 54.2 81.4 60.3 80 -1
GFDL CONSTANT 61.8 78.4 158 235.4 -1
BAMD INCREASING 147.2 233.5 345.4 512.5 -1
LBAR INCREASING 147.5 248 298.9 266.5 -1
MM5B DECREASING 191.4 182.8 140.1 176.3 -1

HWRF is a little slower & doesn't quit make landfall at the end of the run here's GFDL (current 2nd place) yellow is Cat 3 winds the red within that is Cat 4...

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Very very good suggestions Tom...

Quoting TampaTom:
Remember two things when it comes to Richard...

First, this forecast US landfall is still five days away... And, here are the error trends for the five day forecast in blue:



Second, the last time that the Tampa Bay area took a direct landfall was October 25, 1921...

So, it's best to pay attention, make sure those plans are all up to date, and watch carefully...
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Quoting Grothar:


No, I kid a lot, but not about storms.

They just posted this a few minutes ago. One of the dynamic models:



Yep, I've been watching the dynamics for a last couple of phases...looking like more consensus along those lines.

What are we seeing by way of the steering mean?

Good morning, by the way...I was just singing the Pre-Cambrian Tech fight song...do you remember it? LOL
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Quoting Jeff9641:


Well it looks like our dry spell will come to an end!



I would like that. Hopefully, if Richard decides to pay a visit, he will have had too many Cerveza's in the Yucatan.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
1102. JRRP
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Quoting LdyAvalon:
Hi everyone long time lurker here in the Tampa area. Just saw this man named Richard pop up lol. As life would have it, I am suppose to leave Florida next Wednesday to start a new job in Pittsburgh. I am getting a funny feeling that could be delayed a few days. When is Richard predicted to come into the area if all the pieces fall into place?



You have WU Mail
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Quoting RitaEvac:
It was born down there, it will die down there. Not going to Florida.


Absolutely. You hit it 5 by 5.

And we really need the rain.

Oh well, maybe next year.

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Sub-tropical jet is expected to lift north with the steering high that would bring the system in the gulf. Cannot have a jet stream like it depicted right now going through a high pressure system. Only place to go is north, if the forecast verifies...

Then the jet would come back south with the passing trough

Quoting quante:
Given this shear map, could even a strong hurricane survive in the GOM??

http://cimss.ssec.wisc.edu/tropic2/predict/real-time/windmain.php?&basin=&sat=wgE%u220F=shr&am p;zoom=&time =0
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1095. Grothar
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Remember two things when it comes to Richard...

First, this forecast US landfall is still five days away... And, here are the error trends for the five day forecast in blue:



Second, the last time that the Tampa Bay area took a direct landfall was October 25, 1921...

So, it's best to pay attention, make sure those plans are all up to date, and watch carefully...
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1093. Grothar
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1092. quante
Given this shear map, could even a strong hurricane survive in the GOM??

http://cimss.ssec.wisc.edu/tropic2/predict/real-time/windmain.php?&basin=&sat=wgE∏=shr&zoom=&time =0
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Steering direction this time of year in Carribbean is stagnant, they meander down there.
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1090. Grothar
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1088. Jax82
You can see Megi's cold water trail.

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1083. JRRP
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Quoting Jeff9641:


Anybody can call. If you have questions then call them if you wish. They are very nice people there.


Cool...thanks for the info. I'll have to keep this in mind in the future!
Member Since: September 1, 2009 Posts: 0 Comments: 447
Yep: ATCF:

BEGIN
NHC_ATCF
invest_al192010.invest
FSTDA
R
U
040
010
0000
201010211240
NONE
NOTIFY=ATRP
END
RICHARD, AL, L, , , , , 19, 2010, TS, O, 2010101700, 9999999999, , , , , , WARNING, 4, AL192010
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1080. NotJFV
Quoting Jeff9641:


Every model bends this to FL now.

No the do not all take R towards Florida, they may eventually but as of right not NO ALL MODELS DO NOT TAKE THIS INTO FL.
Please make sure to post facts before you write them down.
These are the types of posts that causes WU to go insane.
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1079. Grothar
Didn't think I would be posting my Globe again this season, but here is a view of 90L

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1078. scott39
Quoting SweetHomeBamaGOM:


no thats not what he said at all. he said that currently the sw quad was taking a pounding with wind shear. he is a complete liar.

the weather channel is gone. if you want to trust them, well if your an american you have the right to believe in whatever you want. i just tend to not trust liars, thats all. no offense to you, it was just disgusting to see him lie like that. but to each their own :)

downcasters should love the new weather channel. they will always back up a downcaster lol.
Ok, I thought you were refering to wind direction and the effects on wind shear in the GOM. No offense taken.
Member Since: June 13, 2009 Posts: 0 Comments: 6867
Navy site: Richard

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Wow, now that is an out on the limb statement.

Quoting RitaEvac:
It was born down there, it will die down there. Not going to Florida.
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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.