Three tropical depressions may form by Wedneday in the Atlantic

By: Dr. Jeff Masters , 7:03 PM GMT on September 24, 2007

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Satellite imagery this morning shows that a new surface circulation has developed in the Gulf of Mexico near 23N 93W, about 350 miles southeast of Brownsville, Texas. This new circulation has been labeled 94L by NHC this morning. Heavy thunderstorm activity has begun forming near the center of circulation, and this system has the potential to become a tropical depression by Tuesday. Wind shear is about 15-20 knots over the disturbance, and is expected to remain 15 knots or below for the next three days. The disturbance is headed west-northwest at less than 10 mph, and should bring heavy rains to northern Mexico--and possibly southern Texas--by Wednesday. However, most of the computer models show that 94L may stall before it reaches the coast, then loop erratically in the Gulf for several days. A Hurricane Hunter flight is scheduled to investigate 94L Tuesday afternoon.


Figure 1. Today's lineup of tropical systems to watch.

Lesser Antilles disturbance 97L getting more organized
A tropical wave (97L) is just north of Barbados in the Lesser Antilles Islands. This wave has developed a closed circulation centered over the southern Lesser Antilles Islands, as seen on the 9:10 am EDT pass from the ASCAT satellite. This is confirmed by wind observations from Barbados this afternoon, where the winds have turned to westerly and increased to 20 mph. The latest Satellite imagery shows a marked increase in heavy thunderstorm activity in the past few hours, and a tropical depression could form by Tuesday. The wave is under about 10 knots of wind shear. The shear is forecast to slowly rise to 20 knots by Thursday, which may slow intensification. The future evolution of the storm depends on how close it comes to the mountainous island of Hispaniola. Most of the models predict 97L will pass over the island on Wednesday or Thursday, which would greatly disrupt the storm. None of the models predict 97L will grow stronger than a 55 mph tropical storm for the next four days. There is a band of very high wind shear predicted to lie just north of Hispaniola all of this week, and 97L could well encounter this band of high wind shear Thursday, which would weaken the storm. In any case, this system represents a threat to the Dominican Republic, Haiti, Puerto Rico, and the northern Lesser Antilles Islands, and residents may experience tropical storm conditions as early as Wednesday afternoon. The Hurricane Hunters are on call to investigate 97L Tuesday afternoon, if necessary. This afternoon's flight was canceled.

Links to follow for 97L
Martinique radar
Barbados weather
Dominica weather
Guadaloupe weather
Martinique weather
St. Lucia weather


Figure 2. Microwave image from 11:28 am EDT today showing low-level spiral bands starting to form around 96L. Image credit: Navy/NRL.

Atlantic disturbance 96L midway between Africa and the Lesser Antilles nearing tropical depression strength
A tropical wave (96L) near 9N 33W, midway between Africa and the Lesser Antilles Islands, is moving west-northwest at 10-15 mph. This wave has gotten much more organized this afternoon, as seen in the latest satellite loops. The circulation associated with the wave is unusually large. The storm has been slow to organize, since it is so large and so far south. At the storm's current latitude--9 degrees north of the Equator--it cannot leverage the earth's spin very much to help spin up the huge circulation it has. However, the storm will probably be a tropical depression by Tuesday morning. Low-level spiral bands have already formed, as seen in recent microwave satellite images (Figure 2). This morning's 7:29 am EDT ASCAT pass showed a better defined circular wind pattern with top winds of 25-30 mph. The wave is under about 10 knots of wind shear. The shear forecast is problematic, with some of the models expecting high wind shear later this week, and others keeping the wind shear low. I expect 96L will become at least a weak tropical storm by Wednesday, then we'll have to see how the upper level winds evolve. The storm is expected to gradually work its way north as it crosses the Atlantic, and appears likely to pass north of the Lesser Antilles Islands next week. The last few runs of the GFS model show 96L eventually recurving out to sea next week.

Tropical Storm Jerry
Tropical Depression Jerry is only worth mentioning since it increases our storm totals for the year to ten. Jerry will be gone tonight, absorbed by an extratropical low pressure system.

Hurricane Rita anniversary
Today marks the second anniversary of Hurricane Rita's landfall in Southwest Louisiana. Wunderblogger Mike Theiss has written a blog and posted his usual amazing photos documenting his experience with Hurricane Rita. One of the more remarkable features of the account is his encounter with hundreds of exhausted birds in the eye of Rita. The unfortunate birds got trapped in the eye for days, unable to escape.

I'll have an update Tuesday morning.

Jeff Masters

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2151. ClearH2OFla
4:51 PM GMT on September 25, 2007
Any comment on the CMC model have a storm from key west up to tampa out to east back to ga / fla border
2150. hcubed
3:41 PM GMT on September 25, 2007
"Posted By: FitzRoy at 5:09 PM CDT on September 24, 2007.

I'd love Taz to publish his ignore list - it must be quite a read lol!"


It's probably everyone that has ever commented on his spelling - which makes me #81.
Member Since: May 18, 2007 Posts: 289 Comments: 1639
2149. moonlightcowboy
3:11 PM GMT on September 25, 2007
HyperText Transfer Protocol

...this shows a slight movement west (or possibly south). Could be just a temporary jog, or the center adjusting under the convection. I still believe the models will shift more to the west, as this huge pile of convection slowly pulls itself together and moves just slightly north of due west. Timing is going to be critical to catch the mid-Atlantic trough (if it does at all) to become a fish!
Member Since: July 9, 2006 Posts: 184 Comments: 29598
2148. beell
2:51 PM GMT on September 25, 2007
Is the little swirl at 14N 51W also moving W?
I guess at some point 97l and/or 96l could affect the swirl's direction,. Not yet tho imho
Member Since: September 11, 2007 Posts: 142 Comments: 16478
2147. TexInsAgent
2:46 PM GMT on September 25, 2007
Catadjuster I hope all is well with your daughter
Member Since: September 6, 2007 Posts: 0 Comments: 67
2146. Caymanite
2:37 PM GMT on September 25, 2007
Morning Catadj, hope daughter gets well soon.
Member Since: December 9, 2005 Posts: 0 Comments: 315
2145. help4u
2:36 PM GMT on September 25, 2007
Mark Sudduth on hurricane tracker basically said the season was pretty much over.
Member Since: September 18, 2006 Posts: 0 Comments: 1276
2144. Floodman
2:32 PM GMT on September 25, 2007
Morning, CatAdjuster...some interesting stuff going on. Sorry to hear about your daughter...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
2143. Ivansvrivr
2:27 PM GMT on September 25, 2007
Don't typical la nina years have fewer and weaker fronts through fall which bottles up cold air up north leading to a florida freeze in Feb?
2142. Ivansvrivr
2:22 PM GMT on September 25, 2007
The little red L over Puerto Rico doesnt seem to be turning north though. Looking at the little green lines (Isobars) it doesnt seem to bring a westerly wind into Fl. The Steering low is way north. that could very easily drive storms westward if they slide a little 2 far underneath.
2141. OSUWXGUY
2:21 PM GMT on September 25, 2007
leftovers-

Over tropical oceans the diurnal temperature range is much less than over land. Also, in the tropics you don't have nearly the decrease in sunlight (equator is always 12 hours day/nigt) during the fall that you do in the midlatitudes.
2140. castnblast
2:18 PM GMT on September 25, 2007
Yeah, I saw that system when I was checking out 94l...Just another blob to watch. It does appear to have some surface low w/it, but we need to see if it persists. UL conditions appear favorable for the time being. However, w/ these fronts starting to plow through, I think we are very near the end of hurricane season for the gulf coast in a couple more weeks.
2139. Stingfish
2:17 PM GMT on September 25, 2007
This year has been strange for Atlantic storms.....
2138. catastropheadjuster
2:17 PM GMT on September 25, 2007
Good Morning all. What's going on in the tropics? I have been at home taking care of my 18yr old daughter she was in a bad wreck sunday afternoon, and i haven't been able to look to much. Thanks in Advanced
Sheri
Member Since: August 24, 2006 Posts: 21 Comments: 3671
2137. Bonedog
2:16 PM GMT on September 25, 2007
Ivan

Day 4 fronts
fronts4

Day 5 Fronts
fronts5

Member Since: July 14, 2005 Posts: 14 Comments: 7418
2136. Muffelchen
2:16 PM GMT on September 25, 2007
Posted By: AnnularHurricane at 2:08 PM GMT on September 25, 2007.

karen will be a fish storm...and Mahmoud Ahmedinejad will convert to Judaism.


That's the best example of spelling i've seen on this blog. Well done Annular, setting a good example :-) Incidentally, your well reasoned posts are also an example to others.
Member Since: August 21, 2007 Posts: 0 Comments: 72
2135. Ivansvrivr
2:16 PM GMT on September 25, 2007
This is about as complex as i ever remember the tropics being. And thank goodness everybody here is staying civil. Thank you everybody!
2134. SamTeam
2:15 PM GMT on September 25, 2007
The Good Dr. M has spoken....new blog!
Member Since: September 22, 2007 Posts: 0 Comments: 213
2133. Squid28
2:15 PM GMT on September 25, 2007
Everyone up north is prepping their snowblowers for the upcoming season, meanwhile we are still test runing our generators on the coast.......
Member Since: May 23, 2006 Posts: 0 Comments: 343
2132. kap333
2:15 PM GMT on September 25, 2007
What the HEY!!!

http://www.ssd.noaa.gov/goes/east/gmex/loop-vis.html

Gotta pay attention all the time at this time of year in Florida!
Member Since: October 28, 2002 Posts: 0 Comments: 31
2131. StormJunkie
2:14 PM GMT on September 25, 2007
Back to work, see y'all in a little while.

Quick Links
-Easily navigate forecast models, imagery, marine data, wind data, preparedness info, and much more.

There are also some nice model tutorial videos under the learning section on that page.


Member Since: August 17, 2005 Posts: 26 Comments: 16308
2129. Ivansvrivr
2:13 PM GMT on September 25, 2007
How far south and east does this front get though?
2128. Bonedog
2:12 PM GMT on September 25, 2007
agrred NEwxguy. 87 on thursday and 68 on friday

already started seeing lower 40s at my house cant wait to see what this front brings (rollseyes)
Member Since: July 14, 2005 Posts: 14 Comments: 7418
2127. ecflawthr
2:12 PM GMT on September 25, 2007
97l or its remnants may interact with system coming off of the coast this weekend and develop into something. gfs model hint at this.
Member Since: September 4, 2006 Posts: 1 Comments: 201
2125. StormJunkie
2:10 PM GMT on September 25, 2007
Morning all :~)

Everything seems to still point to Karen heading out to see. Even the 12 BAMM has shifted further N.

The area int he straights of Fla could be something to watch although it does look like it will have some shear to deal with.
Member Since: August 17, 2005 Posts: 26 Comments: 16308
2124. rareaire
2:10 PM GMT on September 25, 2007
we should put an ankle bracelet on big Jim Cantore so we can see what the Weather Cahnnel is really thinking. If Jim heads South you know its not good....LOL
Member Since: August 19, 2007 Posts: 0 Comments: 1601
2123. CZMdivemaster
2:10 PM GMT on September 25, 2007
So far NOAA has named 3 exta-tropical storms and 3 storms that reached tropical strength for less than 6 hours. Seems that no one wants egg on their face after saying it would be another devastating year for hurricanes. Next year, when people start ignoring the warnings, NOAA should bear in mind how many time it has cried wolf.
Member Since: September 25, 2007 Posts: 0 Comments: 1
2122. Bonedog
2:10 PM GMT on September 25, 2007
Karen does have nice banding features and a classic pinwheel structure to her

karen
Member Since: July 14, 2005 Posts: 14 Comments: 7418
2121. CJ5
2:10 PM GMT on September 25, 2007
Based on the steering layers, if Karen stays around 10N there is a real possibility it could avoid the sharp N turn and make a more gradual NW turn. If it holds it W movement until 65W then all bets are off on a fish storm.
Member Since: July 4, 2007 Posts: 0 Comments: 1755
2120. Ivansvrivr
2:09 PM GMT on September 25, 2007
Ivan was a cat 1 in montgomery Al. What's rare is something like Katrina. She was large and bottomed out quickly. Probably mostly because of the loop current.
2119. NEwxguy
2:09 PM GMT on September 25, 2007
bonedog I agree thats a real strong front pushing through the us.Were going to be in the 90's here in new england and 60's by the weekend.
Member Since: September 6, 2007 Posts: 877 Comments: 15709
2118. castnblast
2:09 PM GMT on September 25, 2007
Posted By: AnnularHurricane at 9:00 AM CDT on September 25, 2007.

TWC deserves to eat 35,000,000,000 crows considering how inaccurate they've been this season.And seasons in the past.Lyons didn't think Dean would develop until it got to about 50W.Karen won't be going out to sea.

Yeah, and Humberto was too close to land to develop much past a minimal tropical storm...LOL....
2116. mississippiwx23
2:08 PM GMT on September 25, 2007
The storm off of florida, to me, looks like one that develops from the frontal system that moves off the coast in a few days. It also looks like it might just be carried away with the front. So, it might not be a tropical system at all. Have to watch however, as any frontal system that makes it that far south can easily gain tropical characteristics. It also might be interacting with whatever is left of 97L at that point (hurricane...still an invest? who knows!). But it does look like a possible TD10/Gabrielle type situation.
Member Since: August 20, 2007 Posts: 3 Comments: 683
2115. Ivansvrivr
2:07 PM GMT on September 25, 2007
And I have a phd in rocket science:)
2114. Bonedog
2:06 PM GMT on September 25, 2007
also Karen droped 5mb in 11 1/2hrs I know its nothing spectacular but still something to mention

2007SEP25 024500 2.0 1009.0
2007SEP25 131500 2.6 1004.0
Member Since: July 14, 2005 Posts: 14 Comments: 7418
2111. Ivansvrivr
2:05 PM GMT on September 25, 2007
I agree 100% my handle says enough. Ivan was no 2 mile wide storm. Small ones fluctuate much more rapidly. Remember Ioke last yr in the Pacific?
2110. IKE
2:04 PM GMT on September 25, 2007
Posted By: AnnularHurricane at 9:03 AM CDT on September 25, 2007.
Keyword...models. I'm with Taz, the models are basically rubbish at this point, look how far South this is


Rubbish? Because they don't agree with what you want Karen to do?
Member Since: June 9, 2005 Posts: 23 Comments: 37858
2109. LoneStarWeather
2:04 PM GMT on September 25, 2007
Posted By: Ivansvrivr at 1:56 PM GMT on September 25, 2007.

TWC won't say a word until a red cone touches land somewhere


But TWC is "the hurricane authority". hahaha!
Member Since: September 8, 2001 Posts: 0 Comments: 430
2108. Bonedog
2:03 PM GMT on September 25, 2007
just looked at the Dorvak.

Karen droped another mb in just 30 min

2007SEP25 121500 2.5 1005.0
2007SEP25 124500 2.6 1004.0
Member Since: July 14, 2005 Posts: 14 Comments: 7418
2107. aspectre
2:03 PM GMT on September 25, 2007
To give you some idea of how HUGE Karen is, the center of the TropicalStorm was here when it was named.
Click on the third rectangular button from the bottom, and you'll see the coast of SouthAmerica on the bottom left and Mindelo on SaoVicente of the CapeVerdeIslands near the top left.
Click on the second rectangular button from the bottom and you'll see it's about halfway between Cayenne,FrenchGuiana and Praia,CapeVerdeIslands.
The distance between Cayenne and Mindelo is 2027miles/3262kilometres.
And Karen's influence spans that distance.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
2106. thelmores
2:03 PM GMT on September 25, 2007
So recon will be in the gulf (94L)at noon?

any bets on a TD or not?
Member Since: September 8, 2005 Posts: 0 Comments: 3805
2104. IKE
2:02 PM GMT on September 25, 2007
Annular....this from the 5 am EDST discussion on Karen....

" After that...the large-scale models agree on the
development of a mid/upper-level trough to the northeast of the
Lesser Antilles...which would turn Karen northwestward or
northward."
Member Since: June 9, 2005 Posts: 23 Comments: 37858
2103. Ivansvrivr
2:02 PM GMT on September 25, 2007
Like I said last nite, Dr. lyons was somewhat random in his description of steering currents.
2101. Bonedog
2:01 PM GMT on September 25, 2007
no not Wilma I was refering to the big storms taking a while to get their act together. Once they do though some do spin up to monsters.
Member Since: July 14, 2005 Posts: 14 Comments: 7418

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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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