Disturbance 94L in Central Atlantic; NHC management changes

By: Dr. Jeff Masters , 1:58 PM GMT on August 28, 2007

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A tropical wave midway between Africa and the Lesser Antilles (labeled "invest 94L" by NHC this morning) has become a little better organized this morning, and does have the potential to develop into a tropical depression later this week. Wind shear is a favorable 5-10 knots over 94L, and shear should not be a problem for it over the next few days. The system is not well-organized, with a sloppy, elongated circulation, as seen on last night's QuikSCAT pass. This morning's QuikSCAT pass missed the storm. The system does have a major impediment to development--the presence of a large, dusty area of dry air surrounding its north side (Figure 1). Water vapor satellite loops of the region don't show any significant moistening of the region around 94L occurring, and this will have to happen before the system can develop into a tropical depression. If the storm can develop a better-organized circulation, it will be able to pump more moisture into the surrounding atmosphere and help itself out. Current visible satellite loops shows that this is not happening at present--the thunderstorm activity associated with 94L is rather weak.

None of the reliable computer models develop 94L. The system should track through the Lesser Antilles Islands on Friday, bringing gusty winds and heavy rain. I expect that the earliest 94L could become a tropical depression would be Thursday, and it is unlikely the Lesser Antilles would experience anything worse than a 50 mph tropical storm. It is more likely that 94L will still be a tropical disturbance when it passes through the Lesser Antilles.


Figure 1. Water vapor satellite image of the Central Atlantic from 8:15am EDT 8/28/07. The brown colors denote very dry and dusty air from the Saharan Desert.

Honduras disturbance
A westward-moving tropical wave is bringing heavy rains to Honduras and Nicaragua today. Due to its close proximity to land, development of this wave into a tropical depression is not expected. The wave is under 10-15 knots of wind shear. None of the reliable models are predicting that this system will develop.

Computer model update
The UKMET and GFS models are indicating the possible development of a tropical depression by Thursday or Friday off the coast of Africa. There is a large surge of moisture with at least one strong tropical wave embedded in it coming off the coast of Africa this week. This moister air should make a more favorable environment for a tropical depression to form in than the one 94L finds itself in.

Most of the models also predict a low pressure system will develop off the North Carolina coast along an old frontal boundary on Thursday. Such a development may be an ordinary extratropical low pressure system, but could make the transition to a tropical system if the shear drops low enough.

NHC management changes
Acting director Dr. Ed Rappaport of The National Hurricane Center (NHC) will continue on the job until the end of this hurricane season, NOAA management revealed yesterday. Rappaport replaced director Bill Proenza on July 9, following an extraordinary few months of tumult at NHC. Joining the NHC staff on September 4 will be a new interim deputy director--Bill Read, who currently serves as the meteorologist in charge of the National Weather Service's Houston-Galveston office. Deputy director was the post Rappaport held prior to July 9. Bill Read applied for the directorship of NHC when Max Mayfield retired, but was not awarded the job. His arrival at NHC during the peak of hurricane season will be a welcome addition, as he has considerable experience dealing with hurricane emergencies.

In an apparent effort to follow some of the management changes recommended by the independent review team that performed the snap inspection of NHC in early July (see Attachment 9 of the Senate testimony from July), a new manager of the ten hurricane forecasters has been appointed as well. Rick Knabb, who is one of the six senior hurricane specialists, will be the new manager, and will be Rappaport's backup for TV interviews during hurricane emergencies.

It is still undecided where former director Proenza will wind up, but the chairs of two Senate subcommittees investigating the matter have recommended that Proenza be returned to his former job as head the NWS Southern Region.

Next update
Tomorrow is the 2-year anniversary of Hurricane Katrina. I'll discuss my experience with blogging about the storm, and give an update on 94L and the rest of the tropics.

Jeff Masters

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1294. putintang3
2:54 PM GMT on August 29, 2007
Would someone please answer my questions, i come on here to learn something, i can't learn anything if my questions are not answered. I just what to know what i am looking at. Dog gone it!
Member Since: August 29, 2005 Posts: 2 Comments: 309
1293. Bobbyweather
2:52 PM GMT on August 29, 2007
New blog is up about Katrina and 94L and 95L.
Member Since: September 7, 2006 Posts: 89 Comments: 2649
1292. putintang3
2:51 PM GMT on August 29, 2007
Posted By: hurricane23 at 2:02 PM GMT on August 29, 2007.

This is the wave to place close attention in the coming week or so as it already at a dangerous latitude and looks fairly well organized on morning visibles.


ok hurricane23, in that pic you posted, there two blobs, which one is the potential?
the elongated one or the little round one. Because on the EUMETAT the little round one seems to have rotation.
Member Since: August 29, 2005 Posts: 2 Comments: 309
1291. WeatherfanPR
2:49 PM GMT on August 29, 2007
Right now 94L is organizing but 94L will need to face high wind shear by 60w ahead. I think that's why the gfs weakens the system and some models don't develops nothing and some models only take it to a tropical storm status. Of course conditions can become more favorable but we need to wait at least 2 days.
Member Since: August 23, 2006 Posts: 0 Comments: 1563
1290. putintang3
2:45 PM GMT on August 29, 2007
ok stromw, in your synopsis on 95L, you said "the farther offshore, the better"
the better for what?
the better for development, or the better not to develope?
Member Since: August 29, 2005 Posts: 2 Comments: 309
1289. MZT
2:37 PM GMT on August 29, 2007
new blog up
Member Since: September 24, 2005 Posts: 0 Comments: 793
1288. putintang3
2:36 PM GMT on August 29, 2007
ok guys which one is 95l? where is it heading at the moment?
Member Since: August 29, 2005 Posts: 2 Comments: 309
1287. MZT
2:36 PM GMT on August 29, 2007
I agree with WeatherMSK. My father and I have been discussing how the first frost arrives later than it used to, and how you can harvest tomatoes until the first week of December in N.C. now.

Rememebr Jeff Masters mentioning that the smaller norhtern ice cap could delay the winter. We may need to get out of thinking that hurricane season is mostly September phenominon. Big storms like Wilma in the final week of October may not be as "freak" as they used to be.
Member Since: September 24, 2005 Posts: 0 Comments: 793
1286. hurricane23
2:33 PM GMT on August 29, 2007
Basically my advise with now the meat of the season approaching anything is possible and everything in the tropics should be watched closely.
Member Since: May 14, 2006 Posts: 8 Comments: 13597
1285. Bobbyweather
2:32 PM GMT on August 29, 2007
There's a possibility (but very low) that a subtropical or tropical system might form near 45N 40W! LoL
Member Since: September 7, 2006 Posts: 89 Comments: 2649
1284. hurricane23
2:29 PM GMT on August 29, 2007
Posted By: sporteguy03 at 10:27 AM EDT on August 29, 2007.

Adrain,
I thought 95L is no threat?

Even if this is not a threat recon always will fly into systems this close to land and have a chance at developing.
Member Since: May 14, 2006 Posts: 8 Comments: 13597
1282. sporteguy03
2:27 PM GMT on August 29, 2007
Adrain,
I thought 95L is no threat?
Member Since: July 7, 2005 Posts: 0 Comments: 5120
1281. Annap
2:25 PM GMT on August 29, 2007
I'm leaving for Cuba on Saturday. I hope everything stays calm when I'm away. I don't want to get stuck in Cuba during a storm.
1280. hurricane23
2:24 PM GMT on August 29, 2007
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1015 AM EDT WED 29 AUGUST 2007
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 30/1100Z TO 31/1100Z AUGUST 2007
TCPOD NUMBER.....07-097

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (NORTH OF THE BAHAMAS)
FLIGHT ONE
A. 30/1800Z
B. AFXXX 01FFA INVEST
C. 30/1500Z
D. 29.0N 76.5W
E. 30/1730Z TO 30/2200Z
F. SFC TO 10,000 FT

FLIGHT TWO
A. 31/0600Z
B. AFXXX 02FFA CYCLONE
C. 31/0200Z
D. 28.0N 76.0W
E. 31/0500Z TO 31/0900Z
F. SFC TO 10,000 FT

2. SUCCEEDING DAY OUTLOOK: CONTINUE 12 HRLY FIXES IF
SYTEM NORTH OF THE BAHAMAS REMAINS A THREAT
.
POSSIBLE LOW LEVEL INVEST NEAR 13N 58W AT 31/1800Z
Member Since: May 14, 2006 Posts: 8 Comments: 13597
1279. mccld
2:20 PM GMT on August 29, 2007
Two years ago today ,i spent the day convincing my daughter to leave New Orleans. I was convinced that this was the storm that we had all been talking about because of the information shared on this web site. My thanks goes to all of you and especially Storm Junkie who's passion and information made the difference for me and my family that day. Say a prayer for all who are still healing from that day.
1278. hurricane23
2:19 PM GMT on August 29, 2007
Posted By: StormJunkie at 10:07 AM EDT on August 29, 2007.

h23, being that far north and seeing what the GFS has been showing the last few runs, I think there is a decent chance that Africa wave gets recurved, hopefully....Again though, more wait and see.

Could recurve but my point its latitude is dangerous for long trackers and right its looks good on satelitte imagery for this latitude so far this season.TPC has a 10llmb low attached to the wave.
Member Since: May 14, 2006 Posts: 8 Comments: 13597
1277. quante
2:16 PM GMT on August 29, 2007
This seems to indicate that "window closes" to the US for Cape Verde storms Caribbean would be the hot spot. Statistics of course are just that, but interesting in any event.

Link
Member Since: August 2, 2006 Posts: 0 Comments: 329
1276. sporteguy03
2:10 PM GMT on August 29, 2007
StormJunkie,
Hopefully everything is out to sea:) :):)
Member Since: July 7, 2005 Posts: 0 Comments: 5120
1275. StormJunkie
2:07 PM GMT on August 29, 2007
h23, being that far north and seeing what the GFS has been showing the last few runs, I think there is a decent chance that Africa wave gets recurved, hopefully....Again though, more wait and see.
Member Since: August 17, 2005 Posts: 26 Comments: 15472
1274. TheStormWillSurvive
2:06 PM GMT on August 29, 2007
Posted By: Relix at 2:04 PM GMT on August 29, 2007.

Who activated the cyclogenesis switch?


I did I was tired of no activity
1273. StormJunkie
2:06 PM GMT on August 29, 2007
Well I see we now have 95, and as several have noted the Africa wave is looking pretty impressive. I guess there is an outside shot we have three Atlantic named storms before Sept 1st...Crazy how quickly things can change. The QS on 95 looks fairly sloppy right now, but there are some decent winds with it and as it detaches from the front it should be in a better spot for development.

Lot's of wait and see out there right now..
Member Since: August 17, 2005 Posts: 26 Comments: 15472
1272. hurricane667
2:04 PM GMT on August 29, 2007
i agree hurricane23
Member Since: August 22, 2006 Posts: 0 Comments: 161
1271. IKE
2:04 PM GMT on August 29, 2007
Posted By: TerraNova at 8:59 AM CDT on August 29, 2007.
29/1145 UTC 31.3N 76.2W T1.0/1.0 95L -- Atlantic Ocean
29/1115 UTC 11.2N 44.8W T1.0/1.0 94L -- Atlantic Ocean


They both have T numbers...94L appears a little more organized this morning.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1270. Relix
2:04 PM GMT on August 29, 2007
Who activated the cyclogenesis switch?
Member Since: August 3, 2006 Posts: 0 Comments: 2639
1269. boobless
2:03 PM GMT on August 29, 2007
Re: SW Caribbean/Yucatan
Elongated trof running SW to NE-BOC to N Central GOMEX worrisome.
UL off MS/LA coast.
Just a caution. Most everything associated w/this area moving west.
1268. emagirl
2:03 PM GMT on August 29, 2007
well 2 years since katrina
1267. hurricane23
2:02 PM GMT on August 29, 2007
This is the wave to place close attention in the coming week or so as it already at a dangerous latitude and looks fairly well organized on morning visibles.

wave
Member Since: May 14, 2006 Posts: 8 Comments: 13597
1266. TerraNova
1:59 PM GMT on August 29, 2007
29/1145 UTC 31.3N 76.2W T1.0/1.0 95L -- Atlantic Ocean
29/1115 UTC 11.2N 44.8W T1.0/1.0 94L -- Atlantic Ocean
Member Since: July 30, 2007 Posts: 76 Comments: 4062
1264. cchsweatherman
1:58 PM GMT on August 29, 2007
Good morning to you all. The tropics have become active once again after a one week lull from Dean and Erin. I have just updated my website on both Invests. I still have to wait for more reliable computer models before placing them on my site. It appears to me as if both systems may be getting their act in gear and seem to be developing, albeit slowly. To me, Invest 94L has a better chance of development than 95L, but that could always change. They both have increased convection and clear cyclonic turning. We will have to wait for the surface observations and QuikScat on Invest 95L. Well, I'll be here later on today. Take it easy all.
Member Since: April 14, 2007 Posts: 8 Comments: 5030
1263. hurricane23
1:52 PM GMT on August 29, 2007
Wave behind 94L could really make things interesting as its futher north for starters.

Infrared Image of wave behind 94L
Member Since: May 14, 2006 Posts: 8 Comments: 13597
1262. crowsnest
1:49 PM GMT on August 29, 2007
I may agree with weatherbrat. Atleast until the seasons go back to a more statistical starting point. Maybe the forcast for each season should include duration and begining dates.
1261. weatherbrat
1:48 PM GMT on August 29, 2007
StormW ~

When is your latest update "synopsis" going to post?
1260. TerraNova
1:47 PM GMT on August 29, 2007
Latest rainfall estimates for 95L and 94L:

trmm1

trmm2
Member Since: July 30, 2007 Posts: 76 Comments: 4062
1259. TheStormWillSurvive
1:47 PM GMT on August 29, 2007
Posted By: Crawls at 1:44 PM GMT on August 29, 2007.

What list?


the list I posted a little while before the post asking about the list
1258. weatherbrat
1:45 PM GMT on August 29, 2007
Maybe the official hurricane season will have to change from June 1st - Nov. 30th to July 1st - Dec. 31st!
1257. Crawls
1:44 PM GMT on August 29, 2007
What list?
Member Since: August 17, 2007 Posts: 0 Comments: 272
1256. 21N71W
1:42 PM GMT on August 29, 2007
thanks Terranova !
Member Since: August 1, 2006 Posts: 0 Comments: 180
1255. crowsnest
1:41 PM GMT on August 29, 2007
I agree with the season starting later. We all know the specific heat of water and that surface temps will stay warmer later in the year so storms will have a better chance on that front. I also think november could see 2 or even 3 storms.
1254. Bobbyweather
1:40 PM GMT on August 29, 2007
I see that we have 95L now.
Member Since: September 7, 2006 Posts: 89 Comments: 2649
1253. TerraNova
1:38 PM GMT on August 29, 2007
I live in the Turks and Caicos Islands and I am leaving for Anguilla for a week.So I hope that I will be able to enjoy myself without having to worry rushing home to board up .....yes???

No real need to worry, if the system we're watching does develop it will likely only be a tropical depression or maybe a weak tropical storm. Certainly nothing like Dean. Also if the wave that is currently emerging off Africa develops it will be a while before it affects anybody.
Member Since: July 30, 2007 Posts: 76 Comments: 4062
1252. TheCaneWhisperer
1:37 PM GMT on August 29, 2007
Doesn't look like it Nash! Looks like the latest Quikscatt is loading in on the storm page.
1250. 21N71W
1:33 PM GMT on August 29, 2007
Morning All,
I live in the Turks and Caicos Islands and I am leaving for Anguilla for a week.So I hope that I will be able to enjoy myself without having to worry rushing home to board up .....yes???
Member Since: August 1, 2006 Posts: 0 Comments: 180
1249. TheStormWillSurvive
1:35 PM GMT on August 29, 2007
anyone else want to add there name to the lists
1246. nash28
1:34 PM GMT on August 29, 2007
Morning all.

Did the GFDL not run a 06z package for 94L?
Member Since: July 11, 2005 Posts: 190 Comments: 16972
1244. hurricane23
1:33 PM GMT on August 29, 2007
95L should get picked up....

Models

fff
Member Since: May 14, 2006 Posts: 8 Comments: 13597

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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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