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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new COC based on updated WV loop 18.1N 81.2 W, click on fronts on top selection to see location

Link
Member Since: August 18, 2009 Posts: 0 Comments: 157


LOL at the Invest 19 epic fail.

However, the system IS now expected to make a landfall on Quintana Roo. GFDL and HWRF both predict cat. 3 landfalls.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Cloud tops in excess of -80C are firing almost right atop 19L's circulation. Too bad Recon isn't out there investigating the system.


Why isn't Recon out there? Didn't see any cancellation of the flight plan that was schedule for 7:30 PM EST to 11:30 PM EST.
Member Since: Posts: Comments:
Post 613.
That's some pretty clouds.
Never seen that.
Member Since: October 24, 2005 Posts: 0 Comments: 23080
Quoting Chicklit:


Hi Potts, we'd take it.
Transportation an issue.
FedEx
Member Since: October 9, 2008 Posts: 0 Comments: 8242

looks like megi is sparing hong kong

Member Since: July 11, 2006 Posts: 14 Comments: 11047
Quoting Chicklit:
Nice of you to mention that Scott39 but I loathe antibiotics and prefer to drink lots of water, orange juice, and of course wine.
Starting to finally feel better, thanks.

still spotty


Pay attention to the time stamp. That was from 1837Z, or 2:37PM EST. Convection has markedly increased and the circulation center is now located with the convection.
Member Since: Posts: Comments:
Cloud tops in excess of -80C are firing almost right atop 19L's circulation. Too bad Recon isn't out there investigating the system.
Member Since: Posts: Comments:
Quoting Chicklit:
Nice of you to mention that Scott39 but I loathe antibiotics and prefer to drink lots of water, orange juice, and of course wine.
Starting to finally feel better, thanks.

still spotty

Wine is good!.
Will not deal with the problem,
but you will most likely feel better for a while, and sleep well, and wake up with a headache.
heheheh, sorry, but it's the Truth.
Member Since: October 24, 2005 Posts: 0 Comments: 23080
Quoting pottery:

Not sure you going to get any from this one....
But I could send you some of mine!


Hi Potts, we'd take it.
Transportation an issue.
Member Since: July 11, 2006 Posts: 14 Comments: 11047
Member Since: August 2, 2010 Posts: 21 Comments: 9648
So, i see while i was gone TD 19 is official
Member Since: Posts: Comments:
Quoting shikori:
Has anyone here ever seen a nacreous cloud (mother of pearl clouds)


Member Since: June 9, 2007 Posts: 4 Comments: 15718
Quoting scott39:
Its terrible to have that. Go to the Doc and get a steroid shot and a antibiotic! 2 weeks is way too long.
Heh sometimes my can go on for a month.Now back to weather the thunderstorms have become intense.Now we'll see if they can go over the center.
Member Since: August 14, 2010 Posts: 10 Comments: 15707
Quoting AEKDB1990:
Has there been a storm named Richard before in the Atlantic Basin?


Nope. The farthest this list got to was in 2004 with Otto.

Paula and Richard are firsts for this list.
Member Since: Posts: Comments:
Quoting justalurker:


raining here in south florida now.


Thank God, Halleluliah!
Member Since: July 11, 2006 Posts: 14 Comments: 11047
Quoting Chicklit:
We need a good rain here in ECFL.
I'm going to wishcast it over here.
Floater1
I'm doing the same over here in Sarasota! Hey I think I finally got this posting down!
Member Since: Posts: Comments:
If this does develop, it would have to be a small compact storm right? It has a sweet spot but very hostile all around.
Member Since: August 11, 2010 Posts: 0 Comments: 895
Nice of you to mention that Scott39 but I loathe antibiotics and prefer to drink lots of water, orange juice, and of course wine.
Starting to finally feel better, thanks.

spotty
Member Since: July 11, 2006 Posts: 14 Comments: 11047
Quoting Chicklit:
bring it on.

we need the rain.
dry coughing pollen.


raining here in south florida now.
Member Since: August 18, 2009 Posts: 0 Comments: 157
Quoting Chicklit:
Repeating myself.
Florida needs the rain.

Not sure you going to get any from this one....
But I could send you some of mine!
Member Since: October 24, 2005 Posts: 0 Comments: 23080
Congratulations, Taz.....you did ! (from an old lurker....not a troll..lol..
Member Since: Posts: Comments:
600. washingtonian115
2:05 AM GMT on October 21, 2010
Quoting tropicfreak:
Ok so we know TD 19 has formed. Next 1 million(should be enough) dollar question, where will it go and will it hit FL.
No this doesn't look like a threat to florida as of now.However things can change.But in my opinion only if this dose get to florida it won't be very strong due to unfavorable conditions alotf in the gulf.
Member Since: August 14, 2010 Posts: 10 Comments: 15707
599. Chicklit
2:04 AM GMT on October 21, 2010
Repeating myself.
Florida needs the rain.
Member Since: July 11, 2006 Posts: 14 Comments: 11047
598. Stormchaser2007
2:04 AM GMT on October 21, 2010
Member Since: June 9, 2007 Posts: 4 Comments: 15718
596. 954FtLCane
2:02 AM GMT on October 21, 2010
Quoting sammywammybamy:
a)People Seriously?

b)What Happend to Nicole?

c)What Happend to Paula?

d)Richard is not coming to Florida.

e & f)Go Watch Some TV, Open a Beer, RELAX

a)Yes
b)ask oj
c)ask Simon Cowell, or that goofy wolf/cat in the "Opposites Attract" video.
d)Nixon's Florida whitehouse was in Key Biscayne FL Link
e &f)work night, only 2 more days and I will take you up on the offer.

** Too early to tell but I feel FL doesn't have much to worry about. It'll interesting to see how this plays out in the next few days though.
Member Since: September 30, 2008 Posts: 0 Comments: 108
595. Chicklit
2:02 AM GMT on October 21, 2010
bring it on.

we need the rain.
dry coughing pollen.
Member Since: July 11, 2006 Posts: 14 Comments: 11047
594. Stormchaser2007
2:02 AM GMT on October 21, 2010
18z HWRF

Member Since: June 9, 2007 Posts: 4 Comments: 15718
593. doorman79
2:02 AM GMT on October 21, 2010
Quoting pottery:
Good evening all.
So, TD19, eh?
Going to keep everyone guessing for a while, to figure where this one will end up.
Models generally favouring a SW track for the present.
But with so little movement, this could hang around and conditions can change, affecting the steering.
Interesting little system....


Aw hell, we will take it. Maybe wash that oil out :(
Member Since: August 11, 2010 Posts: 0 Comments: 895
592. tropicfreak
2:01 AM GMT on October 21, 2010
Ok so we know TD 19 has formed. Next 1 million(should be enough) dollar question, where will it go and will it hit FL.
Member Since: September 2, 2006 Posts: 110 Comments: 6814
591. justalurker
2:00 AM GMT on October 21, 2010
what is the chance of this becoming hurricane by morning? could it intensify like paula..hmmm

sure looks convection is starting to flare up big time.
Member Since: August 18, 2009 Posts: 0 Comments: 157
590. sunlinepr
2:00 AM GMT on October 21, 2010
Quoting caymanlurker:

That is a lot of dry air; is there a forecast for this? Also, do the latest models have the same initial Lat/Lon as the position of the new TD COC under the convection i.e. can we place any reliance upon them? Thanks


I think that Levi's post considered your concerns very well;
Link
Member Since: August 2, 2010 Posts: 21 Comments: 9648
589. tropicfreak
1:59 AM GMT on October 21, 2010
Quoting Tazmanian:
YES !


a full house now i this need it too be come a name and it will even be better


round 3


90L be comes hermine

91L be comes IGOR

92L be comes .KARL


93L be comes JULIA

94L be comes LISA


95L be comes Matthew

96L be comes NICOLE

97L be comes Otto


98L be comes Paula

99L be comes TD 19


Which will likely happen. That is interesting that all of the pair of 10 invests became named storms.
Member Since: September 2, 2006 Posts: 110 Comments: 6814
587. kmanislander
1:57 AM GMT on October 21, 2010
Starting to look a little fierce



Member Since: August 19, 2006 Posts: 0 Comments: 15671
586. pottery
1:57 AM GMT on October 21, 2010
Good evening all.
So, TD19, eh?
Going to keep everyone guessing for a while, to figure where this one will end up.
Models generally favouring a SW track for the present.
But with so little movement, this could hang around and conditions can change, affecting the steering.
Interesting little system....
Member Since: October 24, 2005 Posts: 0 Comments: 23080
585. Stormchaser2007
1:56 AM GMT on October 21, 2010
Tropical Depression Nineteen

Member Since: June 9, 2007 Posts: 4 Comments: 15718
584. tropicfreak
1:55 AM GMT on October 21, 2010
Quoting sammywammybamy:
People Seriously?

What Happend to Nicole?

What Happend to Paula?

Richard is not coming to Florida.

Go Watch Some TV, Open a Beer, RELAX


Or a coke if you are underage.
Member Since: September 2, 2006 Posts: 110 Comments: 6814
583. caymanlurker
1:53 AM GMT on October 21, 2010
Quoting sunlinepr:

That is a lot of dry air; is there a forecast for this? Also, do the latest models have the same initial Lat/Lon as the position of the new TD COC under the convection i.e. can we place any reliance upon them? Thanks
Member Since: September 3, 2009 Posts: 0 Comments: 22
582. HurrMichaelOrl
1:53 AM GMT on October 21, 2010
I second that, Chicklit.
Member Since: July 13, 2007 Posts: 0 Comments: 950
581. washingtonian115
1:53 AM GMT on October 21, 2010
Quoting HCW:
Yikes


Thats what you call a wide range of model guidence.
Member Since: August 14, 2010 Posts: 10 Comments: 15707
580. tropicfreak
1:52 AM GMT on October 21, 2010
Quoting doorman79:


I thought it was a her! Ow well


If its a her, then it's stormkat.
Member Since: September 2, 2006 Posts: 110 Comments: 6814
579. sunlinepr
1:51 AM GMT on October 21, 2010
Member Since: August 2, 2010 Posts: 21 Comments: 9648
578. DontAnnoyMe
1:50 AM GMT on October 21, 2010
Quoting washingtonian115:
All I do is skip a post that I don't wont to read.Simple as that.Like people in here do me.


That's a good plan. Wish the feeders would do likewise.

HPC has the system dying over the Yucatan on Day 6

Link
Member Since: September 21, 2010 Posts: 1 Comments: 3690
577. sunlinepr
1:49 AM GMT on October 21, 2010
Member Since: August 2, 2010 Posts: 21 Comments: 9648
576. Chicklit
1:49 AM GMT on October 21, 2010
We need a good rain here in ECFL.
I'm going to wishcast it over here.
Floater1
Member Since: July 11, 2006 Posts: 14 Comments: 11047

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.