98L may develop this weekend; 97L no threat

By: Dr. Jeff Masters , 11:57 AM GMT on October 11, 2012

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A tropical wave located about 350 miles east of the Lesser Antilles Islands (Invest 98L) is headed west-northwest at about 10 - 15 mph, and is a threat to develop into a tropical depression this weekend. The disturbance has a modest amount of spin and a large amount of heavy thunderstorms, as seen on satellite loops and Barbados radar. The thunderstorms have shown more organization this morning, but there is no obvious surface circulation visible on satellite imagery. This morning's ASCAT pass showed top winds of 30 - 35 mph near 15°N, 55°W. Wind shear is a high 20 - 30 knots over 98L, the atmosphere is moist, and ocean temperatures are a very warm 30°C. With wind shear expected to diminish on Saturday to the moderate range, 10 - 20 knots, 98L may be able to develop into a tropical cyclone this weekend. The disturbance has a high amount of support for development among the reliable computer models. The NOGAPS model predicts 98L will develop into a tropical depression or tropical storm on Sunday, about 400 hundred miles north of Puerto Rico. The GFS model predicts 98L will develop on Saturday, when the center will be very close to the northernmost Lesser Antilles Islands. The ECMWF model predicts a more westerly path for 98L into the southeast Bahama Islands, with development delayed until Monday. The models are unified in forecasting that 98L will turn to the north by Monday and be drawn into a trough of low pressure. It does not appear that 98L will be a threat to the U.S. In their 8 am Tropical Weather Outlook, NHC gave 98L a 50% chance of becoming a tropical cyclone by Saturday morning. A hurricane hunter aircraft is scheduled to visit 98L on Friday afternoon.


Figure 1. Morning satellite image of Invest 98L approaching the Lesser Antilles Islands.

Invest 97L east of the Bahamas
A tropical wave located about 250 miles east of the central Bahama Islands (Invest 97L) is headed slowly southwards. The disturbance is well-organized, with a developing surface circulation and a respectable area of heavy thunderstorms, as seen on satellite loops. Wind shear is a high 20 knots over 97L, and the shear has pushed all the storm's heavy thunderstorms to its east side. Shear is expected to increase sharply later today as a cold front overtakes the system. This cold front should be capable of destroying 97L by Friday.

Jeff Masters

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171. VR46L


GFS 12Z 60 HRS IN

clearing the Islands and out to sea for 98L...



Member Since: March 1, 2012 Posts: 0 Comments: 6898
16L/TC/D/NO NAME
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Quoting Neapolitan:
A trained spotter In Mohave, AZ, just reported quarter-size (1") hail.

FWIW, I've lived along the Front Range of the Rockies in Colorado, and have spent many months in the Great Plains, but the two heaviest hail events I've ever experienced were in Southern California, one in August and the other in January


Severe thunderstorms are quite rare in Southern California, particularly in the coastal regions.

But I recall a storm that happened in Orange County, CA in August of 1979 when I was there that was as bad as anything I have ever seen in Florida. This storm had intense cloud-to-ground lightning, large hail, straight-line wind gusts over 75 mph. and about 1.50 inches of rain. An inch and a half of rain is a monstrous total in that area for a single event that lasts only an hour or less.

On rare occasions during the monsoon season the tongue of moisture from the tropical Pacific and the Gulf of California which causes the monsoon effect further to the east over AZ and NM can reach as far west as the L.A. basin. When it gets there if it clashes with the more common and cooler maritime flow from the west, this can cause a gust front to form, allowing for the development of unusually powerful thunderstorms. The orographic effect produced by the various coastal mountain ranges can further enhance this effect. Nevertheless, all of this rarely happens.

Later in the year, jet stream aberrations in combination with some Pacific moisture flowing up from the south can also allow for localized severe wx development. Either way, it is an anomaly when it happens in that region because the normal weather patterns there feature much more stable air at all levels in the atmosphere.
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Quoting SFLWeatherman:

If you noticed, the "L" is more west from where the models started. They need to update those models and readjust them. JMO
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Quoting 7544:
yep

yep looks like it wants to go s ssw today the ? is could it also turn to the west ? be fun if it does to completee the loop the loop lol





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Quoting bohonkweatherman:
Got about an inch of rain here in less than 15 minutes this morning southeast of Buda Tx. Not much was in the forecast so it surprised everyone


You needed that! radar estimates not showing hardly anything though.
Member Since: July 14, 2008 Posts: 1 Comments: 9628
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161. 7544
Quoting wunderkidcayman:
NHC cone takes TD16 SW
yep

yep looks like it wants to go s ssw today the ? is could it also turn to the west ? be fun if it does to completee the loop the loop lol

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12z Surface Analysis. As Kman said,it will pass South of Barbados.

Member Since: April 29, 2009 Posts: 75 Comments: 14243
Quoting AussieStorm:
Goodnight all, Stay well, stay safe, Enjoy your weather, cause that's the only weather you have :-)
Good night Aussie.
Member Since: September 27, 2007 Posts: 1 Comments: 21173
This looks nasty..
Member Since: September 27, 2007 Posts: 1 Comments: 21173
Quoting RitaEvac:
Got about an inch of rain here in less than 15 minutes this morning southeast of Buda Tx. Not much was in the forecast so it surprised everyone
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156. VR46L
TD 16 in rainbow...

Member Since: March 1, 2012 Posts: 0 Comments: 6898
.
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Quoting washingtonian115:
2012 belongs to the frontal systems this year as that is how most of them orginated/formed from.It all started with Alberto..


I disagree. Whilst there have been a number of frontal systems, the majority have been truly tropical in nature. By my counts:

5 frontal: Alberto, Beryl, Chris, Michael, 16.

9 tropical: Debby, Ernesto, Florence, Helene, Gordon, Isaac, Joyce, Kirk, Leslie, Nadine.

And I'll leave Oscar up for debate.

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Member Since: September 27, 2007 Posts: 1 Comments: 21173
Quoting stormwatcherCI:
If there is a low-level ridge building north of TD 16 wouldn't that close the weakness or something ? Not really sure how to put that but trust you know what I mean.

yes I think so
Member Since: June 13, 2009 Posts: 2 Comments: 11925
151. kwgirl
3:16 PM GMT on October 11, 2012
Quoting SLU:
Man, the NHC wins the award for the world's most conservative meteorological organisation.

000
ABNT20 KNHC 111133
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT THU OCT 11 2012

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A BROAD AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS
LOCATED ABOUT 350 MILES EAST-SOUTHEAST OF THE WINDWARD ISLANDS.
SHOWER AND THUNDERSTORM ACTIVITY HAS INCREASED A LITTLE NEAR THE
LOW DURING THE LAST FEW HOURS...AND ENVIRONMENTAL CONDITIONS APPEAR
CONDUCIVE FOR GRADUAL DEVELOPMENT OF THIS LARGE DISTURBANCE OVER
THE NEXT COUPLE OF DAYS. THIS SYSTEM HAS A MEDIUM CHANCE...50
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS
AS IT MOVES WEST-NORTHWESTWARD AT 10 TO 15 MPH. REGARDLESS OF
DEVELOPMENT...STRONG GUSTY WINDS AND HEAVY RAINFALL ARE POSSIBLE
ACROSS PORTIONS OF THE LESSER ANTILLES DURING THE NEXT COUPLE OF
DAYS. ADDITIONAL INFORMATION ON THIS DISTURBANCE CAN BE FOUND IN
HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WATHER SERVICE.

SHOWER AND THUNDERSTORM ACTIVITY HAS CHANGED LITTLE OVER THE PAST
FEW HOURS IN ASSOCIATION WITH A SMALL AREA OF LOW PRESSURE LOCATED
ABOUT 250 MILES NORTHEAST OF THE CENTRAL BAHAMAS. THERE IS STILL A
SMALL WINDOW OF OPPORTUNITY FOR A TROPICAL DEPRESSION TO FORM
BEFORE THE LOW MERGES WITH A COLD FRONT LATER TODAY. THIS SYSTEM
HAS A MEDIUM CHANCE...50 PERCENT...OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS AS IT MOVES SLOWLY SOUTHWARD. ADDITIONAL
INFORMATION ON THIS DISTURBANCE CAN BE FOUND IN HIGH SEAS FORECASTS
ISSUED BY THE NATIONAL WATHER SERVICE.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
Maybe they are just sensitive to the reaction the locals in South Florida would have to any more hype. I believe Andrew was weak and in the same area before it blew up to the montster it became. The idea of weather forecasts is to make people aware without frightening them. And I think any forecast should leave the window open for change. After all, the meteorologists don't have a crystal ball to tell them that a certain event is definitely going to happen. It's weather which changes very rapidly. Good morning everyone.:)
Member Since: March 28, 2008 Posts: 0 Comments: 1532
150. stormwatcherCI
3:15 PM GMT on October 11, 2012
Quoting stormwatcherCI:
If there is a low-level ridge building north of TD 16 wouldn't that close the weakness or something ? Not really sure how to put that but trust you know what I mean.
Member Since: October 9, 2008 Posts: 0 Comments: 8344
149. AussieStorm
3:14 PM GMT on October 11, 2012
Goodnight all, Stay well, stay safe, Enjoy your weather, cause that's the only weather you have :-)
Member Since: September 30, 2007 Posts: 9 Comments: 15935
148. RitaEvac
3:14 PM GMT on October 11, 2012
Member Since: July 14, 2008 Posts: 1 Comments: 9628
147. AussieStorm
3:14 PM GMT on October 11, 2012
Quoting belizeit:
I just got to quote doc from a few hrs ago "98L may develop this weekend; 97L no threat" this just shows how unreliable weather can really be .

Yeah, I questioned that as the NHC had both at 50%, both could develop or both could not develop. The NHC has now said 97L is TD16 but will dissipate in 48hrs, and have issued no watches or warning, so what's the point of upgrading it.
Member Since: September 30, 2007 Posts: 9 Comments: 15935
146. belizeit
3:08 PM GMT on October 11, 2012
I just got to quote doc from a few hrs ago "98L may develop this weekend; 97L no threat" this just shows how unreliable weather can really be .
Member Since: January 10, 2010 Posts: 0 Comments: 920
145. AussieStorm
3:08 PM GMT on October 11, 2012
Quoting Bobbyweather:
Well, have a good rest of the day! I'm going to sleep; it's almost midnight here.

Well if it's almost midnight there that means it's 2am here.

Ulladulla on the South Coast of NSW has had 213.4mm of rain since 9am Thursday morning. That's 8.4inches, and much more is to come until 9am, could see 300mm/11.8in.

Latest Weather Observations for Ulladulla
Member Since: September 30, 2007 Posts: 9 Comments: 15935
144. Tropicsweatherpr
3:07 PM GMT on October 11, 2012
First mission for 98L will be on Friday afternoon and TD 16 will get a visit also on Friday afternoon.

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1050 AM EDT THU 11 OCTOBER 2012
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 12/1100Z TO 13/1100Z OCTOBER 2012
TCPOD NUMBER.....12-145

I. ATLANTIC REQUIREMENTS
1. TROPICAL DEPRESSION SIXTEEN
FLIGHT ONE --TEAL 73--
A. 12/1600Z
B. AFXXX 0116A CYCLONE
C. 12/1200Z
D. 24.8N 74.0W
E. 12/1530Z TO 12/1830
F. SFC TO 10,000 FT

2. SUSPECT AREA (LESSER ANTILLES)
FLIGHT ONE --TEAL 71-- FLIGHT TWO --TEAL 72--
A. 12/1800Z A. 13/0600Z, 1200Z
B. AFXXX 01DDA INVEST B. AFXXX 0217A CYCLONE
C. 12/1700Z C. 13/0500Z
D. 15.5N 62.5W D. 17.0N 64.0W
E. 12/1730Z TO 12/2130Z E. 13/1530Z TO 13/1200Z
F. SFC TO 10,000 FT F. SFC TO 10,000 FT

3. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 6-HRLY FIXES IF
SYSTEM IN EASTERN CARIBBEAN IS STILL A THREAT.
Member Since: April 29, 2009 Posts: 75 Comments: 14243
143. hydrus
3:06 PM GMT on October 11, 2012
Quoting ncstorm:


the second one will be more east..
I think so too.
Member Since: September 27, 2007 Posts: 1 Comments: 21173
142. hydrus
3:05 PM GMT on October 11, 2012
98L may have a couple low centers.
Member Since: September 27, 2007 Posts: 1 Comments: 21173
141. ncstorm
3:01 PM GMT on October 11, 2012
Quoting hydrus:
I am interested to see the new GFS run. It appears that the next two systems will produce significant severe weather events, the second one being larger and more potent.


the second one will be more east..
Member Since: August 19, 2006 Posts: 13 Comments: 15260
140. stormwatcherCI
3:00 PM GMT on October 11, 2012
Quoting kmanislander:
Interesting language from the discussion on TD 16. This system may not dissipate as quickly as forecasted

THE INITIAL MOTION ESTIMATE IS A SLOW SOUTHWARD DRIFT...180/01.
AS THE LOW-LEVEL RIDGE BUILDS IN TO THE NORTH OF THE DEPRESSION A
SLOW SOUTHWESTWARD MOTION IS EXPECTED TO BEGIN LATER TODAY AND
CONTINUE THROUGH DISSIPATION. THE NHC TRACK IS CLOSE TO A BLEND OF
THE GFS AND ECMWF FORECASTS THROUGH THAT TIME.

SINCE THE TRACK FORECAST KEEPS THE CENTER OF THE DEPRESSION TO THE
NORTHEAST OF THE CENTRAL BAHAMAS THROUGH DISSIPATION...A TROPICAL
STORM WATCH IS NOT NEEDED FOR THOSE ISLANDS AT THIS TIME.

If there is a low-level ridge building north of TD 16 wouldn't that close the weakness or something ? Not really sure how to put that but trust you know what I mean.
Member Since: October 9, 2008 Posts: 0 Comments: 8344
139. Tazmanian
2:58 PM GMT on October 11, 2012
the recon will be vary help full for TD 16


I. ATLANTIC REQUIREMENTS
1. TROPICAL DEPRESSION SIXTEEN
FLIGHT ONE --TEAL 73--
A. 12/1600Z
B. AFXXX 0116A CYCLONE
C. 12/1200Z
D. 24.8N 74.0W
E. 12/1530Z TO 12/1830
F. SFC TO 10,000 FT


2. SUSPECT AREA (LESSER ANTILLES)
FLIGHT ONE --TEAL 71-- FLIGHT TWO --TEAL 72--
A. 12/1800Z A. 13/0600Z, 1200Z
B. AFXXX 01DDA INVEST B. AFXXX 0217A CYCLONE
C. 12/1700Z C. 13/0500Z
D. 15.5N 62.5W D. 17.0N 64.0W
E. 12/1730Z TO 12/2130Z E. 13/1530Z TO 13/1200Z
F. SFC TO 10,000 FT F. SFC TO 10,000 FT

3. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 6-HRLY FIXES IF
SYSTEM IN EASTERN CARIBBEAN IS STILL A THREAT.
Member Since: May 21, 2006 Posts: 5091 Comments: 115069
138. hydrus
2:56 PM GMT on October 11, 2012
Quoting washingtonian115:
This looks exciting :).
I am interested to see the new GFS run. It appears that the next two systems will produce significant severe weather events, the second one being larger and more potent.
Member Since: September 27, 2007 Posts: 1 Comments: 21173
136. HurrMichaelOrl
2:55 PM GMT on October 11, 2012
Quoting 12george1:
If TD 16 survives somehow, will it go near my area (West Palm Beach, Florida)?


It would take a miracle for that to happen this time of year (October, from that angle of approach). I would bet it happens once or twice a century, maybe. I would not mind the rain though.
Member Since: July 13, 2007 Posts: 0 Comments: 1116
135. FtMyersgal
2:53 PM GMT on October 11, 2012
Quoting TomballTXPride:

I'm afraid she'll be sheared to death fresh out of the gate.


Have to agree with you Tomball. She is running out of time IMO
Member Since: September 16, 2010 Posts: 0 Comments: 1216
134. Neapolitan
2:51 PM GMT on October 11, 2012
Quoting 1900hurricane:
This looks highly unusual. How often do the low deserts adjacent to the Western Colorado River experience hail?
A trained spotter In Mohave, AZ, just reported quarter-size (1") hail.

FWIW, I've lived along the Front Range of the Rockies in Colorado, and have spent many months in the Great Plains, but the two heaviest hail events I've ever experienced were in Southern California, one in August and the other in January
Member Since: November 8, 2009 Posts: 4 Comments: 13524
133. Bobbyweather
2:51 PM GMT on October 11, 2012
Well, have a good rest of the day! I'm going to sleep; it's almost midnight here.
Member Since: September 7, 2006 Posts: 89 Comments: 2655
132. WxLogic
2:50 PM GMT on October 11, 2012
Good Morning... TD#16.
Member Since: August 14, 2008 Posts: 4 Comments: 4972
131. kmanislander
2:48 PM GMT on October 11, 2012
Interesting language from the discussion on TD 16. This system may not dissipate as quickly as forecasted

THE INITIAL MOTION ESTIMATE IS A SLOW SOUTHWARD DRIFT...180/01.
AS THE LOW-LEVEL RIDGE BUILDS IN TO THE NORTH OF THE DEPRESSION A
SLOW SOUTHWESTWARD MOTION IS EXPECTED TO BEGIN LATER TODAY AND
CONTINUE THROUGH DISSIPATION. THE NHC TRACK IS CLOSE TO A BLEND OF
THE GFS AND ECMWF FORECASTS THROUGH THAT TIME.

SINCE THE TRACK FORECAST KEEPS THE CENTER OF THE DEPRESSION TO THE
NORTHEAST OF THE CENTRAL BAHAMAS THROUGH DISSIPATION...A TROPICAL
STORM WATCH IS NOT NEEDED FOR THOSE ISLANDS AT THIS TIME.

Member Since: August 19, 2006 Posts: 0 Comments: 15813
130. weathermanwannabe
2:48 PM GMT on October 11, 2012
Shear is expected to increase sharply later today as a cold front overtakes the system. This cold front should be capable of destroying 97L by Friday.

That cold front is pretty strong so I am siding with the NE solution at the moment..........We should know by tomorrow how TD 16 reacts to it. That jet stream along with 40 knots of sheer is a lot to overcome.

Link

Link
Member Since: August 8, 2006 Posts: 0 Comments: 9111
129. Bobbyweather
2:48 PM GMT on October 11, 2012
Quoting VR46L:


No it has not I saw was it Nadine? called on here and navy 24 hrs too early

But they cancelled the upgrade before advisory time, so that wouldn't count.

invest_RENUMBER_al142012_al912012.ren
FSTDA
R
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040
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0000
201209101416

Maybe you're misunderstanding my point. I said 'at a late time'. What I think you meant is 'at any time'. I think that's the reason for the confusion.
Member Since: September 7, 2006 Posts: 89 Comments: 2655
128. 12george1
2:48 PM GMT on October 11, 2012
If TD 16 survives somehow, will it go near my area (West Palm Beach, Florida)?
Member Since: August 27, 2010 Posts: 0 Comments: 247
127. washingtonian115
2:47 PM GMT on October 11, 2012
Quoting hydrus:
This looks like a potent system, and almost all the models are pickin it up.
This looks exciting :).
Member Since: August 14, 2010 Posts: 10 Comments: 16964
125. wunderkidcayman
2:46 PM GMT on October 11, 2012
Quoting stormwatcherCI:
Not from there though. We usually may get something forming in the SW Caribbean. I just looked it up and it says there have only been two hurricanes which formed in the area 98L is in that travelled through the entire Caribbean. One being Joan which crossed over into the Pacific and became Miriam. Joan has been retired.


Sorry for this slightly late reply

That is true but it's not uncommon for that type of track to happen
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123. VR46L
2:45 PM GMT on October 11, 2012
Quoting Bobbyweather:

Well, this year it was always true. Not sure for any other years.


No it has not I saw was it Nadine? called on here and navy 24 hrs too early
Member Since: March 1, 2012 Posts: 0 Comments: 6898
122. washingtonian115
2:45 PM GMT on October 11, 2012
Quoting VR46L:


Definitely true the ugly lookers were the tropical ones in origin ...
That is so true..Like Oscar for a example.Poor fella couldn't even get Helene to look at him twice.
Member Since: August 14, 2010 Posts: 10 Comments: 16964
121. Bobbyweather
2:44 PM GMT on October 11, 2012
NHC only took into account the TAFB estimates. They excluded the SAB's T3.0. Wonder why... maybe they thought it was just an error.
Member Since: September 7, 2006 Posts: 89 Comments: 2655

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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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