97L in Western Caribbean Still a Threat to Develop

By: Dr. Jeff Masters , 1:58 PM GMT on October 02, 2013

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A tropical disturbance (Invest 97L) over the Western Caribbean is moving to the northwest at 10 mph and is generating heavy rains over the Cayman Islands and Western Cuba. Grand Cayman Island had picked up 2.32" (59 mm) of rain as of 9:30 am EDT on Wednesday. Satellite loops show that 97L has a modest area of heavy thunderstorms that have increased substantially in areal coverage and in intensity since Tuesday, but there is little rotation apparent. Cayman Islands radar also does not show any rotation to the echoes, but there are several prominent low-level bands of heavy rain. The storm has low wind shear of 5 - 10 knots to work with, as well as an upper-air anticyclone aloft that is providing good ventilation above it. Dry air is over the Yucatan Peninsula and Gulf of Mexico, as seen on water vapor satellite loops, and this dry air is slowing development. Ocean temperatures are a very warm 29°C (84°F). An Air Force hurricane hunter flight is scheduled for Wednesday afternoon.


Figure 1. Wind forecast for 2 pm EDT Saturday October 5, 2013, from runs of the GFS model done six hours apart. The more recent run, initialized at 06Z (2 am EDT) on Wednesday, October 2 (left panel) predicts that 97L will have top winds below 35 knots (40 mph, light orange colors). This run showed the center of 97L making landfall in the Florida Panhandle about 120 miles east of Alabama late Saturday afternoon.The run initialized six hours earlier, at 00Z (right panel), showed a stronger storm, with top winds of 40 - 45 knots (46 - 52 mph.) This run showed the center of 97L making landfall near the Alabama/Florida border Saturday night. The images were generated using our wundermap with the model layer turned on.

Forecast for 97L: development into at least a tropical depression likely
Wind shear is expected to remain low on Wednesday, then steadily increase to the moderate range on Thursday, then to the high range on Friday, according to the latest SHIPS model forecast. On Wednesday night, 97L will cross the northeastern tip of Mexico's Yucatan Peninsula, bringing 3 - 6" of rain to the peninsula and to Western Cuba. Passage over the Yucatan will act to disrupt the storm. The atmosphere will grow drier as 97L moves northwards over the Gulf of Mexico on Thursday and Friday, and the drier air combined with increasing wind shear will retard development, making rapid intensification unlikely. A trough of low pressure and an associated cold front will be moving through Louisiana on Saturday, and the associated upper-level westerly winds will be able to turn 97L more to the northeast as it approaches the coast on Friday. The GFS model develops 97L into a tropical storm, and predicts landfall will occur along the Florida Panhandle. The European model, which does not develop 97L into a tropical storm, is farther west, taking the storm over Eastern Louisiana. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave 97L 2-day odds of development of 40%, and 5-day odds of 50%. I give a 30% chance 97L will be Tropical Storm Karen with top winds of 40 - 60 mph at landfall between Louisiana and the Florida Panhandle on Saturday, a 5% chance it will be stronger, and a 65% chance it will be a tropical depression or mere tropical disturbance. Heavy rains of 3 - 6" can be expected falling the coast from Louisiana to the Florida Panhandle on Saturday, even if 97L does not develop into a tropical depression.


Figure 2. MODIS satellite image of 97L, taken at 12:30 pm EDT on October 2, 2013. Image credit: NASA.

Tropical Storm Jerry in the Central Atlantic no threat
Tropical Storm Jerry continues to slowly wander over the Central Atlantic, far from land. Jerry is not a threat to any land areas.

Jeff Masters

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Time: 19:05:00Z
Coordinates: 18.2167N 84.3W
Acft. Static Air Press: 977.4 mb (~ 28.86 inHg)
Acft. Geopotential Hgt: 293 meters (~ 961 feet)
Extrap. Sfc. Press: 1010.7 mb (~ 29.85 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 155 at 26 knots (From the SSE at ~ 29.9 mph)
Air Temp: 21.8C (~ 71.2F)
Dew Pt: 21.2C (~ 70.2F)
Peak (10s) Flt. Lvl. Wind: 28 knots (~ 32.2 mph)
SFMR Peak (10s) Sfc. Wind: 28 knots* (~ 32.2 mph*
)
SFMR Rain Rate: 5 mm/hr* (~ 0.20 in/hr*)

???
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Quoting 756. scottsvb:


Well scott, you said this will be a TS when recon gets in there and will be a hurricane soon and maybe a extreme 1 (cat 3 or higher)... lets see what 5pm says.
This could be a hurricane in the NE GOM in 3 days..I even stated that last night but your current obs are based on midlevel sat judgements and anyone who has taken classes or just followed weather for years knows that a tropical system isn't based by the midlevel.


Wait 19N 85W is mid level? Think again sir.

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She's trying to moisten the environment in front of her too.

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I am not wishcasting; I have just cancelled my in-shore Sunday fishing trip near Apalachicola......Rough seas and falling pressures, regardless of the configuration of storm, are not favorable conditions. Turns the bite off on the fish and very hard to see Redfish tails on the flats sicking out of the water in 4-6 foot swells.

I am not casting at all.............. :(
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Quoting 744. Patrap:
I saw it furst.

Nope was Scott.
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Quoting 729. Patrap:

Seems to have a more northern motion than last night.
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Quoting 737. IKE:
The drama on here is rapidly intensifying. May see a pinhole eye soon.


So long as nobody pumps the ridge..we'll be OK :)
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Member Since: July 3, 2005 Posts: 426 Comments: 128676
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Mojo said hello to October the whole month!
Member Since: July 25, 2010 Posts: 0 Comments: 2642
Quoting 735. StormTrackerScott:


LOL! Wow lets attack Scott day well I'll dish it back so keep it coming.



Well scott, you said this will be a TS when recon gets in there and will be a hurricane soon and maybe a extreme 1 (cat 3 or higher)... lets see what 5pm says.
This could be a hurricane in the NE GOM in 3 days..I even stated that last night but your current obs are based on midlevel sat judgements and anyone who has taken classes or just followed weather for years knows that a tropical system isn't based by the midlevel.
Member Since: January 22, 2006 Posts: 0 Comments: 1690
Quoting 732. GTstormChaserCaleb:
Sorry if this has been posted already, but by far the strongest the GFS has shown this system.



Experimental FIM-9 Zeuz:

yes you see that 990 MB also...tight and strong.
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Yeeeeeeep, I'm going to San Antonio this Friday, yall hold the fort down for whatever this 97L does, not even gonna be watching. Good luck and GOD speed.
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Quoting 735. StormTrackerScott:


LOL! Wow lets attack Scott day well I'll dish it back so keep it coming.



No you were just a bit too optimistic based upon the visual and what is really happening. Focus was on the wrong area.

LL-vorticity


ML-vorticity

Member Since: June 25, 2011 Posts: 2 Comments: 3733


Member Since: July 3, 2005 Posts: 426 Comments: 128676
This is one reason to be concerned if I lived across the northern Gulf Coast.

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Quoting 737. IKE:
The drama on here is rapidly intensifying. May see a pinhole eye soon.
Someone in Florida has just declared a pinhole eye looking to him.
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Well hello there....97l....what, may I ask, are your intentions?
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748. VR46L
Quoting 678. whitewabit:


Ya might want to check the current map ...

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now it would be GOOD, if it takes a left hand hook and goes into texas..they Need the rains there.
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.DISCUSSION...VARIABLY TO PARTLY CLOUDY SKIES PREVAILED ACROSS
THE LOCAL ISLANDS TODAY. SHOWERS WITH THUNDERSTORMS AND LOCALLY
HEAVY RAINFALL WERE NOTED ACROSS PORTIONS OF THE CORDILLERA
CENTRAL AS WELL AS WEST PUERTO RICO IN THE AFTERNOON. WINDS WERE
EASTERLY AT 10 TO 15 MPH WITH COASTAL TEMPERATURES IN THE LOW
90S.

THE LOCAL ISLANDS WILL BECOME UNDER THE INFLUENCE OF A MID TO UPPER
LEVEL TROUGH WHICH WILL INTERACT WITH PATCHES OF LOW LEVEL MOISTURE
AND LOCAL EFFECTS TO PRODUCE CLOUDINESS AND SHOWERS WITH THUNDERSTORMS
ACROSS PORTIONS OF THE LOCAL ISLANDS. IN FACT...MODEL GUIDANCE
SUGGESTED A SHARP INCREASE IN PRECIPITABLE WATER OVER THE NEXT FEW
DAYS WITH VALUES PEAKING NEAR 2.2 INCHES FRIDAY NIGHT-SATURDAY MORNING.
AS A RESULT THURSDAY THROUGH THE EARLY PART OF THE UPCOMING WEEKEND...
UNDER A MOIST/UNSTABLE AIR MASS AND THE PREVAILING WIND FLOW...
EXPECT THE CONTINUED TREND OF PASSING SHOWERS ACROSS USVI AND
EASTERN PUERTO RICO DURING THE MORNING HOURS...FOLLOWED BY
AFTERNOON CONVECTION WHICH WILL BE FOCUSED BUT NOT LIMITED TO
WESTERN PUERTO RICO. SUNDAY INTO EARLY NEXT WEEK...MOIST AND
UNSTABLE CONDITIONS WILL CONTINUE TO PREVAIL ACROSS THE FORECAST
AREA AS A SECOND UPPER LEVEL LOW DEVELOPS NORTHWEST OF THE LOCAL
AREA AND A BROAD SURFACE TROUGH DOMINATES THE CENTRAL AND WESTERN
CARIBBEAN.

Soooooo.... no sig rain event any more (who is surprised?) but only passing showers. GREAT!!!!! (grumpy)
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I believe there is a broad circulation at the surface. The low-level poleward inflow is not all that strong, but does tell me that a closed circulation is most likely present. Most of the spin I believe people are seeing is mid-level. Remember when looking at visible satellite imagery you must look at less reflective clouds to dictate low level motions.

http://www.ssd.noaa.gov/PS/TROP/floaters/97L/imag ery/rgb-animated.gif
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I saw it furst.

Member Since: July 3, 2005 Posts: 426 Comments: 128676
Quoting 732. GTstormChaserCaleb:
Sorry if this has been posted already, but by far the strongest the GFS has shown this system.



Experimental FIM-9 Zeuz:



Tightly packed as well that is why I think this will be a hurricane soon.
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Quoting 723. weathermanwannabe:


I would have to defer to the technical peramitters (closed circulation with TD force sustained winds by Hunter confirmation or satellite presentation) but I am giving 97L an A+ for effort today.......... :)


We've seen the west winds. Yes, they're light and a bit broad around the center, but with what it has, I say td. It's not the prettiest...



...but it ain't horrible neither and has done very well improving through the day.
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Quoting 701. SuperStorm093:
Please state the reasons why I am a troll? Just because I forecast without wishcasting doesnt make me a troll.

Just please stop antagonizing everyone and hopefully they'll do the same for u. I don't ever post just lurk mostly and I'm getting tired of seeing u and a few others constantly going back and forth. Save that crap when there is nothing going on weather-wise. Please everyone stop with the non sense. Lurking used to be so much fun....
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Quoting 728. 7544:


yep it could stall giving more time for the trof to catch it and turn it ne sooner than the models show keep one eye on yhis one for now still not out of the woods yet timing is the key now
exactly..i remember early model runs that had a tampa bullseye..watch and wait.
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Beaumont....

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Quoting 701. SuperStorm093:
Please state the reasons why I am a troll? Just because I forecast without wishcasting doesnt make me a troll.
Wishcasters always call others trolls.They love to see cat.5 landfall anywhere and then sorry about it.
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737. IKE
The drama on here is rapidly intensifying. May see a pinhole eye soon.
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There is a decent low at the surface, winds aren't strong enough for tropical cyclone status just yet. Convection is on the increase as well.
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Quoting 714. scottsvb:
StormTrackerScott isn't a Met and probably never took classes of atmospheric science. He does have a wild passion for weather and hurricanes and you can see it gets to his judgements by not making sound statements on what is Really happening Meteorolgy wise with 97L and past systems. Hype by just looking at Satellite and not understanding basic concepts of how a tropical system develops- shows. While he can post anything he wants to say in a public forum, you can tell from the hype that he does that while people that took classes or just people who been understanding tropical development over years knows that you have to base alot of factors into it. Recon btw beats out everything that a satellite/local radar or anything else.


LOL! Wow lets attack Scott day well I'll dish it back so keep it coming.

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Quoting 721. StormTrackerScott:


Wrong all day no sir that would be you. Dry air infact desert like you said, shear, you name it but you can call everyone else out on here but when someone replies back you can't take it.



Your perception of reality is very skewed. I feel sorry for you.

Ignored. Bye.
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Quoting 636. hydrus:
Large feeder bands are developing.


Why are they called "feeder bands?" Does it mean the cyclone's energy is fueled by them?
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Sorry if this has been posted already, but by far the strongest the GFS has shown this system.



Experimental FIM-9 Zeuz:

Member Since: June 30, 2013 Posts: 12 Comments: 8437
and,,,in 2 weeks we could be doing this guessing all over again lol....
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Quoting 718. IKE:
28.3 knots (~ 32.6 mph)
yeah i kinda figured that it would be close to a TD so it looks like 30-35mph storm. This is gonna be a close call.Lets see what recon has more of
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728. 7544
Quoting 667. LargoFl:
I am watching this one very closely..still a few days to go yet I think


yep it could stall giving more time for the trof to catch it and turn it ne sooner than the models show keep one eye on yhis one for now still not out of the woods yet timing is the key now
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Member Since: January 1, 2008 Posts: 0 Comments: 3436
Product: Air Force High Density (HDOB) Message (URNT15 KNHC)
Transmitted: 2nd day of the month at 19:08Z
Date: October 2, 2013
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 301)
Mission Purpose: Investigate sixth suspect area (flight in the North Atlantic basin)

Mission Number: 1

Observation Number: 24

19:08:30Z 18.383N 84.400W 977.0 mb
(~ 28.85 inHg) 292 meters
(~ 958 feet) 1010.2 mb
(~ 29.83 inHg) - From 116° at 13 knots
(From the ESE at ~ 14.9 mph) 23.5°C
(~ 74.3°F) 22.3°C
(~ 72.1°F) 14 knots
(~ 16.1 mph) 16 knots
(~ 18.4 mph) 1 mm/hr
(~ 0.04 in/hr) 14.9 knots (~ 17.1 mph)
114.3%
Time Coordinates Aircraft
Static Air Pressure Aircraft
Geopotential Height Extrapolated
Surface Pressure D-value Flight Level Wind (30 sec. Avg.) Air Temp. Dew Point Peak (10 sec. Avg.)
Flight Level Wind SFMR
Peak (10s Avg.) Sfc. Wind SFMR
Rain Rate Estimated Surface Wind (30 sec. Avg.)
Using Estimated Reduction Factor Peak Wind at Flight Level to
Est. Surface Reduction Factor

HDOB Observations

Independent Calculations from Tropical Atlantic

At 18:59:00Z (first observation), the observation was 236 miles (380 km) to the E (80°) from Belize City, Belize.

At 19:08:30Z (last observation), the observation was 248 miles (400 km) to the SE (140°) from Cancún, Quintana Roo, México.
Member Since: July 3, 2005 Posts: 426 Comments: 128676
Quoting 712. LAbonbon:


how's the blog ambiance now?


not so good... but funny from my point of view
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Quoting 711. GatorWX:
You guys really don't think this is a td huh?


Not based on the little I have seen so far but the HH has a lot of time to go yet.
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Quoting 711. GatorWX:
You guys really don't think this is a td huh?


I would have to defer to the technical peramitters (closed circulation with TD force sustained winds by Hunter confirmation or satellite presentation) but I am giving 97L an A+ for effort today.......... :)
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722. JRRP
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Quoting 690. MississippiWx:


Lol. So, you have been wrong consistently all day. Now, I'm a know-it-all and we are going to start calling names?

Time to just put you on ignore since you can't debate like an adult.


Wrong all day no sir that would be you. Dry air infact desert like you said, shear, you name it but you can call everyone else out on here but when someone replies back you can't take it.

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Quoting 711. GatorWX:
You guys really don't think this is a td huh?
it kinda is too me not yet TS but TD yes i can say very close!
Member Since: July 25, 2010 Posts: 0 Comments: 2642
Quoting 708. CCkid00:

so......what are YOU thinking? I am not too far from where you live.


National Weather Service New Orleans la
113 PM CDT Wednesday Oct 2 2013

Long term...

the biggest challenge in the forecast comes in the long range
period as several factors play an important role in the forecast
for this weekend.A trough is expected to dip southeast across the
Pacific northwest towards the Rocky Mountains later this week.
Saturday into Sunday this feature will be amplifying as it tracks
across the middle section of the country. A cold front will be
marching south ahead of the trough towards the County Warning Area this weekend.
At the same time models depict a tropical low moving into the
northern Gulf of Mexico. Models are having a hard time resolving
this feature and probably will continue to have trouble with it
until it gets more developed. The hurricane center highlights this
area and has this disturbance at a 50 percent chance of becoming a
tropical cyclone over the next 3 to 5 days.

Taking a peep at the models again today it looks like the European model (ecmwf)
continues to be slower with the progression of the front and would
allow the tropical feature to get further west and much closer to
the forecast area. The GFS on the other hand is more progressive
with the front by about 12 hours and keeps the tropical feature to
the east of the forecast area keeping the bulk of the
precipitation to the east of the area. Have generally kept the
same forecast from previous forecasts but have bumped up probability of precipitation some
this weekend. After the front fall will make an appearance and you
will definitely feel the difference in the overnight lows as thy
will dip into the 50s early next week and daytime highs will be in
the low 80s. High pressure builds in behind the front yielding for
some clear days. 13/mh

Read more at http://www.wunderground.com/DisplayDisc.asp?Discus sionCode=LIX&StateCode=LA&SafeCityName=New_Orleans #FkCAHk1JYYRxf4m4.99
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718. IKE
28.3 knots (~ 32.6 mph)
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Quoting 716. MississippiWx:
If the convection will continue firing over the broad center, it will help tighten up the core. It definitely looks the part of a TC on satellite.



and per surface obs...
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If the convection will continue firing over the broad center, it will help tighten up the core. It definitely looks the part of a TC on satellite.

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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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