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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Quoting 1161. Tropicsweatherpr:


Yeah,raining there.


Passing showers, but still great given the HUGE LACK OF RAIN :-)

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Quoting 1106. kmanislander:


May get it shortly if the HH can verify a new center. The old location they were looking at would not have made the grade.


I am looking at the Visible Floater and there appears to be some small tight circulation at 18.4W 85.3W.

Or am I a certifiable Wishcaster?

I love that name. There should be a Diploma issued once certified.
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Quoting 1159. CaribBoy:

You live in such a beautiful place. Lucky.
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1163. IKE
Blow up right near the COC....


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1162. Torito
Quoting 1150. stormpetrol:
I think the HH is flying through a large developing and intensifying Tropical System where the pressure is dropping continuously all around, just my opinion.


What i have been thinking is that the system may grow to a huge size, instead of strengthening..
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Quoting 1154. CaribBoy:


Good for you as is raining there.
Member Since: April 29, 2009 Posts: 75 Comments: 14340
1160. Drakoen
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After six years it looks like what will become Karen is finally back for revenge.Lol.
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coc showing would not it be something if storm tracker scott is right. if so i eat some bird.
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Does anyone use wundermap and look at the models that way? If so, how can you tell which model run it is? Looked everywhere, and can't see where that's stated (for any of the models).
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Quoting 1119. VR46L:



Very easy to see the rotation in the storm, I believe it is a closed low. Great outflow with it too, as many others said, if you had only the imagery, you would probably insist that this is a TD or a TS. This is a great looking invest, glad I've tuned in. Sorta dissapoining that recon isn't finding higher winds, I agree with TWX13 that recon should search and see what they could find a little to the north and east.
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Quoting 1147. Drakoen:


...Gradually deepening...


Agree.
Member Since: July 15, 2006 Posts: 17 Comments: 10284
Quoting 1147. Drakoen:


...Gradually deepening...


Should be more rapid once DMAX comes around.
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1151. sar2401
Quoting Maineweatherguy20023:
I must say-I've lurked here for a loooong time and I must say-in recent months, theres been waay too much quarreling. It's convinced Gro to leave :( and as much as I love the info, the sites etc you guys post, I have to leave now because the quarreling. I might come back later but its really annoying to listen to. This is the weakness of this blog. Its a great forum filled with smart people. I have greatly expanded my knowledge of the weather here. I would love to continue to do that but there's too much fighting. I would ignore people but it seems everyone's joining in. I hope this can get cleared up.

It gets cleared up by people who aren't here to stir the pot posting good information and putting those who are either annoying or have nothing to contribute on ignore. Everyone is not joining in fighting, and I've been here a long time and seen it much worse than this. If you simply use the ignore button, those that like to fight will end up fighting with each other and we won't have to see it. Except for an occasional quote, it works just fine for me. Up to you, of course, but if you can find a weather forum where there are no fights and no trolls, let me know. I haven't found one in the almost 30 years I've been using what's now called the Internet.
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I think the HH is flying through a large developing and intensifying Tropical System where the pressure is dropping continuously all around, just my opinion.
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1149. GatorWX
Member Since: January 1, 2008 Posts: 0 Comments: 3460
Post #1134

Why are you here?
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1147. Drakoen
Quoting 1138. MississippiWx:


20.2N 86.0W


...Gradually deepening...
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RECCO:
Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 2nd day of the month at 20:41Z
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: 09

Mandatory Data...

Observation Time: Wednesday, 20:36Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 19.9N 85.3W
Location: 132 miles (212 km) to the SE (131°) from Cancún, Quintana Roo, México.
Turbulence: Light
Conditions Along Flight Route: In the clear
Pressure Altitude: 310 meters
Flight Level Wind: From 200° at 24 knots (From the SSW at ~ 27.6 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 21°C
Flight Level Dew Point: 21°C
Weather (within 30 nautical miles): Thunderstorm(s)
Mean Sea Level Pressure (MSLP): 1007 mb (extrapolated)

Optional Data...

Estimated Surface Wind: From 200° at 25 knots (From the SSW at ~ 28.7 mph)

Remarks Section...

Surface Wind Speed (likely by SFMR): 25 knots (~ 28.8mph)


Latest Wind: Time: 20:58:30Z
Coordinates: 20.5833N 86.3W
Acft. Static Air Press: 977.2 mb (~ 28.86 inHg)
Acft. Geopotential Hgt: 268 meters (~ 879 feet)
Extrap. Sfc. Press: 1007.4 mb (~ 29.75 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 73° at 13 knots (From the ENE at ~ 14.9 mph)
Air Temp: 23.5°C (~ 74.3°F)
Dew Pt: 21.6°C (~ 70.9°F)
Peak (10s) Flt. Lvl. Wind: 13 knots (~ 14.9 mph)
SFMR Peak (10s) Sfc. Wind: 7 knots (~ 8.0 mph)
SFMR Rain Rate: 0 mm/hr (~ 0 in/hr)




Possible center:

Time: 20:47:30Z
Coordinates: 20.0833N 85.8167W
Acft. Static Air Press: 977.3 mb (~ 28.86 inHg)
Acft. Geopotential Hgt: 263 meters (~ 863 feet)
Extrap. Sfc. Press: 1007.1 mb (~ 29.74 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 121° at 3 knots (From the ESE at ~ 3.4 mph)
Air Temp: 24.0°C (~ 75.2°F)
Dew Pt: 22.1°C (~ 71.8°F)
Peak (10s) Flt. Lvl. Wind: 3 knots (~ 3.4 mph)
SFMR Peak (10s) Sfc. Wind: 6 knots (~ 6.9 mph)
SFMR Rain Rate: 1 mm/hr (~ 0.04 in/hr)
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Quoting 1142. IKE:

That's where I see the spin. This will be in the GOM by tomorrow morning.


Well, that was the location of that pressure reading. Lol.
Member Since: July 15, 2006 Posts: 17 Comments: 10284
My thinking is, if the center of circulation of 97L forms to the northeast of the old one, you know a big shift on the track guidance could follow.
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Press: 1006.8 mb
Member Since: May 23, 2012 Posts: 0 Comments: 4686
1142. IKE

Quoting MississippiWx:


20.2N 86.0W
That's where I see the spin. This will be in the GOM by tomorrow morning.
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1141. SLU
Quoting 1121. CaribBoy:
Where is my storm ....


It's so dry here that the ground has literally split open. Only in March/April/May does this happen.

I've given up.

I'm just waiting for the weather Gods to finally pull the plug on this frustrating season.



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The S shape pattern is indicative of dying wind shear and improving significant outflow channels developing equator ward and poleward. Low level spiral banding is potentially developing as well, all indications are that we are a go for development and intensification. Moistening environment around 97L will keep the dry air from interfering during DMIN.
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Quoting 1129. IKE:
1006.8 mb
(~ 29.73 inHg)


20.2N 86.0W
Member Since: July 15, 2006 Posts: 17 Comments: 10284
1137. Torito
Quoting 1127. TropicalAnalystwx13:
Here is the 2013-14 TWC winter storm naming criteria:

- National Weather Service winter storm warnings must be posted.

- The winter storm must be affecting either a) a large population center or b) a multi-state region.

- The winter storm must be historical, memorable, or otherwise unusual (such as the current one) in nature.

- The time for significant impacts must generally be within 48 hours.


Will we get through the alphabet this year? it is a pretty decent possibility.....
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The developing system appears to be moving on a more northerly direction if you look at the animantion
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Quoting 1120. hydrus:
There hunting surface lows..:)


I gathered :-)
Member Since: August 19, 2006 Posts: 0 Comments: 15842
we have WINTER STORM ATLAS LETS GO!
Member Since: July 31, 2013 Posts: 0 Comments: 925
1133. VR46L
Quoting 1118. sar2401:

Do you have a link to these latest models? I have yet to see the GFS model (the only reliable model of the three you referred to) that brings 96L up to hurricane strength. If I missed it, I apologize. If not, don't join the crowd that tries to make things look worse than they are and scare people. It's really not funny.


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1132. LafLA
Quoting 957. yoboi:



what do you think the plane is spraying in the clouds????;)


Spray and Pray
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Quoting 1107. Maineweatherguy20023:
I must say-I've lurked here for a loooong time and I must say-in recent months, theres been waay too much quarreling. It's convinced Gro to leave :( and as much as I love the info, the sites etc you guys post, I have to leave now because the quarreling. I might come back later but its really annoying to listen to. This is the weakness of this blog. Its a great forum filled with smart people. I have greatly expanded my knowledge of the weather here. I would love to continue to do that but there's too much fighting. I would ignore people but it seems everyone's joining in. I hope this can get cleared up.


An ignore feature which also prevents any quote being seen of the ignored would be great. The people I have ignored are seen anyway in quotes. That's crap!
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1130. hydrus
Quoting 1106. kmanislander:


May get it shortly if the HH can verify a new center. The old location they were looking at would not have made the grade.
From invest to T.D.?, or invest to Karen.?
Member Since: September 27, 2007 Posts: 1 Comments: 21432
1129. IKE
1006.8 mb
(~ 29.73 inHg)
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What is wrong with storms this year.They look better when they don't have low level circulations (cough cough Dorian)
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Here is the 2013-14 TWC winter storm naming criteria:

- National Weather Service winter storm warnings must be posted.

- The winter storm must be affecting either a) a large population center or b) a multi-state region.

- The winter storm must be historical, memorable, or otherwise unusual (such as the current one) in nature.

- The time for significant impacts must generally be within 48 hours.
Member Since: July 6, 2010 Posts: 113 Comments: 32286
Quoting 1122. TheDawnAwakening:
Outflow is improving rapidly around the system.

Agreed
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Quoting 1062. bigwes6844:
every state has a model! nice!

except texas :P
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What is taking the ftp site so long.
Member Since: June 11, 2013 Posts: 20 Comments: 3212
Recon in the system now. Looks like the low may be closed although its hard to say, and there is no VDM yet.


Regardless there are high winds occurring in the southern quadrant and in the eastern to ENE quadrants and the pressure is low. Overall structure is vastly improved over yesterday with both a clear mid and low level vortex apparent in visible imagery.


I would say its very likely unless something changes this is declared a tropical storm later tonight or early tomorrow.

There is a chance in my mind for this to develop into a Hurricane in spite of the forecast conditions ahead of it so the Gulf Coast is going to need to watch this carefully.
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Outflow is improving rapidly around the system.
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Where is my storm ....
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1120. hydrus
Quoting 1117. kmanislander:
The HH has gone off on another run this time to the NW without intersecting the original run to the South.

Odd looking pattern
There hunting surface lows..:)
Member Since: September 27, 2007 Posts: 1 Comments: 21432
1119. VR46L


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1118. sar2401
Quoting pensacolastorm:
Just checked latest models. Looks to me if they are increasing in intensity. Looks like the GFS, HWRF and GFDL have a strong TS or Hurricane impacting NWFL.

Do you have a link to these latest models? I have yet to see the GFS model (the only reliable model of the three you referred to) that brings 96L up to hurricane strength. If I missed it, I apologize. If not, don't join the crowd that tries to make things look worse than they are and scare people. It's really not funny.
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The HH has gone off on another run this time to the NW without intersecting the original run to the South.

Odd looking pattern
Member Since: August 19, 2006 Posts: 0 Comments: 15842
Area forecast discussion
National Weather Service New Orleans la
341 PM CDT Wednesday Oct 2 2013


Long term...
the main focus late week through the weekend relates to the tropics.
A tropical wave is currently tracking northwest across the western
Carribean just east of the Yucatan. A hurricane hunter aircraft is
currently flying through the system to investigate. The latest from
the National Hurricane Center currently is calling for a 70 percent
chance of this wave developing into a tropical cyclone in the next 5
days. Medium range models send mixed messages on the development of
the wave. The European model (ecmwf) keeps it open while the GFS suggests a closed
circulation develops. These models were not designed to forecast
cyclogenesis of tropical cyclones. However... can give a good idea
of timing.
Unfortunately...large differences between the two at this
time. The GFS brings the tropical system across the coastal waters
Friday night/Saturday morning. European model (ecmwf) about 24 hours slower with a
similar but slightly further west track. The main determining
factor is approaching upper trough and associated cold front.
The
initial closed upper low will drop out of the Pacific northeast
towards the Rocky Mountains. From there the low will curl northeast
towards the upper Mississippi River valley while the base of the
trough still surges south and east on Saturday. The GFS has been
more accurate with faster solutions with the most recent couple
frontal passages which leads to leaning towards it vs the European model (ecmwf). If
thats the case and the County Warning Area remains on the western side of the
tropical system...most of the rain will remain east of the area with
only coastal waters and adjacent parishes/counties being impacted
with very rough seas and coastal flooding. If upper trough is
slower...the tropical system will make it further north before
curving northeast. At this time...the general consensus of model solutions
bring the trough in faster so the tropical system curves northeast
earlier but the range does go from the western side of the County Warning Area to
the Florida Panhandle so it remains to be seen which Route it/ll
take.
No big changes made to probability of precipitation this weekend but may need too drop
probability of precipitation if on the dry side of things.
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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.