Two African waves worth mentioning

By: Dr. Jeff Masters , 18. heinäkuuta 2009 klo 15:51 (GMT)

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There are two African tropical waves worth mentioning today, though neither looks particularly threatening. A tropical wave near 12N 45W, about 1200 miles east of the Lesser Antilles Islands (97 L), is moving west at 15 - 20 mph. This wave is now surrounded by an area of very dry air from the Sahara Desert. The dry air has disrupted most of the wave's heavy thunderstorm activity, and will continue to make it difficult for this system to develop over the next 2 - 3 days. Wind shear is a modest 10 knots over the disturbance, and should remain in the moderate 10 - 15 knot range over the next 2 - 3 days. Thereafter, shear is expected to rise to 20 - 30 knots. This morning's QuikSCAT pass showed no evidence of a surface circulation, and only a modest wind shift associated with 97L. The National Hurricane Center is giving this system a low (less than 30% chance) of developing into a tropical depression in the next 48 hours.

A second tropical wave now approaching the northern Lesser Antilles Islands is under 30 knots of wind shear, and has little prospect of development due to the high shear. However, the wave will bring heavy rain to the islands over the next two days.

None of the computer models are forecasting tropical storm development over the next seven days, and I don't expect either of the two African waves mentioned today to develop over at least the next three days.


Figure 1. Current satellite image of African wave 97L, 1200 miles east of the Lesser Antilles Islands.

I'll have an update Sunday afternoon.
Jeff Masters

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2300. Gorty
19. heinäkuuta 2009 klo 18:11 (GMT)
When you look at this model, http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8midshr.html

Do you look at both levels, or just one or the other to determine if something will form?
Member Since: 8.11.2008 Posts: 12 Comments: 1058
2299. Gorty
19. heinäkuuta 2009 klo 17:57 (GMT)
A couple models with the latest run does strenthen AL97. But, the HWARF and GFDL is "saying" anything. If those two arn't saying anything, then it probably won't develop. Because isn't the HWARF and the GFDL trustworthy models?

The SHF5 model brings this thing to a Cat 1 at 120 hours.
Member Since: 8.11.2008 Posts: 12 Comments: 1058
2298. all4hurricanes
19. heinäkuuta 2009 klo 16:52 (GMT)
Quoting WAHA:

Omar october Paloma november

I know but I meant august or later. anyway the main point is the history of hurricanes from last year do not support the notion of a cyclone developing in the eastern Caribbean in July
Member Since: 29.03.2008 Posts: 0 Comments: 2338
2297. SELAliveforthetropic
19. heinäkuuta 2009 klo 16:33 (GMT)
I vote B
Member Since: 12.08.2006 Posts: 0 Comments: 59
2296. juniort
19. heinäkuuta 2009 klo 16:25 (GMT)
Thank you StormwatcherCI for your welcome
Member Since: 19.07.2009 Posts: 0 Comments: 69
2295. stormwatcherCI
19. heinäkuuta 2009 klo 16:20 (GMT)
Grothar and juniort welcome and you will get all the information you need and then some. There are some very knowledgeable people here and then there are the trolls so take some comments with a grain of salt.
Member Since: 9.10.2008 Posts: 0 Comments: 8242
2294. stormwatcherCI
19. heinäkuuta 2009 klo 16:17 (GMT)
Quoting HurricaneSwirl:


yes but only omar could form in the east caribbean. all the others could not get started in the east caribbean. well fay did too be she wasn't particularly strong, she just was moving very slow and landfalled in florida 4 times XD
Gustav formed around 67 w which I think is still basically eastern Caribbean. Has anyone noticed the flare-up of convection with the blob that moved through the islands yesterday. I think it is s of Puerto Rico now.
Member Since: 9.10.2008 Posts: 0 Comments: 8242
2293. juniort
19. heinäkuuta 2009 klo 16:14 (GMT)
i should probably introduce myself here and say that I'm new here, so folks help me along. i am also watching 97L carefully, but no infor as yet from Barbados met service
Member Since: 19.07.2009 Posts: 0 Comments: 69
2292. PORTCHARLOTTE72
19. heinäkuuta 2009 klo 16:06 (GMT)
dr steve lyons didnt spend more than 2 seconds discussing 97l in the tropical update it was like it wasnt even there he spent more time talking about the rain in florida i live in swest florida it hasent rained here in 3 weeks
2291. BenBIogger
19. heinäkuuta 2009 klo 16:00 (GMT)
Quoting JRRP:
where is the dead zone?


The Eastern Caribbean
Member Since: 19.03.2009 Posts: 0 Comments: 1419
2290. stormpetrol
19. heinäkuuta 2009 klo 15:59 (GMT)
97L is starting to ventilate and still headed due west , at least on close up visible sat imagery. TD by 11pm tonight if this keeps up , imo.
Member Since: 29.04.2007 Posts: 0 Comments: 7506
2289. StormJunkie
19. heinäkuuta 2009 klo 15:59 (GMT)
Dr M's new blog

Member Since: 17.08.2005 Posts: 26 Comments: 15472
2288. HurricaneSwirl
19. heinäkuuta 2009 klo 15:58 (GMT)
Quoting Drakoen:


hmm, the main blob of convection in the center looks like its expanding. interesting.
Member Since: 7.07.2008 Posts: 2 Comments: 3237
2285. Drakoen
19. heinäkuuta 2009 klo 15:57 (GMT)
New Blog
Member Since: 28.10.2006 Posts: 57 Comments: 29714
2284. PensacolaDoug
19. heinäkuuta 2009 klo 15:57 (GMT)
Mornin' SJ. Something to track finally!
Member Since: 25.07.2006 Posts: 0 Comments: 519
2283. sporteguy03
19. heinäkuuta 2009 klo 15:57 (GMT)
Stormjunkie this observation is key as well, let's see if the winds turn to the NE and goes counter-clockwise when 97L comes near if so there might be something low level there.


Grantley Adams, Barbados (Airport)
Updated: 55 min 29 sec ago
87 °F
Partly Cloudy
Humidity: 62%
Dew Point: 76 °F
Wind: 23 mph from the East
Wind Gust: -
Pressure: 29.99 in
Visibility: 15.0 miles
Clouds: Few 1772 ft
Mostly Cloudy 29528 ft
(Above Ground Level)

Member Since: 7.07.2005 Posts: 0 Comments: 5120
2282. Lower4216
19. heinäkuuta 2009 klo 15:57 (GMT)
Okay .. what does all of this mean for someone who is leaving Thursday out of Mobile, AL on a cruise to Cozumel? Is it gonna be bumpy?
Member Since: 29.08.2006 Posts: 0 Comments: 27
2281. pottery
19. heinäkuuta 2009 klo 15:57 (GMT)
Trinidad weather now
90 f
47% humid
11 miles vis
wind ENE 10 mph
pressure 1015

not much in that...
Member Since: 24.10.2005 Posts: 0 Comments: 23080
2280. WxLogic
19. heinäkuuta 2009 klo 15:57 (GMT)
I wouldn't bother much looking at how 12Z GFS handles this one as it did not initialize it correctly. 00Z should be a good run... we're lucky of 18Z comes out to be a decent one.
Member Since: 14.08.2008 Posts: 4 Comments: 4881
2279. JRRP
19. heinäkuuta 2009 klo 15:56 (GMT)
where is the dead zone?
Member Since: 16.08.2007 Posts: 0 Comments: 5084
2278. hurricane23
19. heinäkuuta 2009 klo 15:56 (GMT)
Quoting Drakoen:
That upper level trough is either going to make or break 97L.


Hey Drak,

Lol little sucker just noticed 97 is back up just looking at obs out there and for now i cant fine a surface circulation but convection has somewhat consolidated overnight i'll give it that.Now as far as its future track a deepening trof off low pressure along the southeast coast should induce shear and a northwesterly turn eventually.

PS...Just ran an infrared loop and yes some pretty decent outflow is starting to take shape.
Member Since: 14.05.2006 Posts: 8 Comments: 13597
2277. IKE
19. heinäkuuta 2009 klo 15:56 (GMT)
Quoting jurakantaino:
Dr. Lyons did his best to avoid mentioning the "invest", his words:" In the Mean time there is another wave approaching the island that will bring a couple of showers to the antilles"


jeez doc...go surf....

Member Since: 9.06.2005 Posts: 23 Comments: 37858
2276. HurricaneSwirl
19. heinäkuuta 2009 klo 15:56 (GMT)
Quoting DDR:

Lets hope it doesn't rapidly intensify,the islands will welcome the rain,thats for sure.


dont think it will, its moving a little too fast, has an upper level trough that needs to move, heat potential isn't that high but i could be wrong about that part.
Member Since: 7.07.2008 Posts: 2 Comments: 3237
2275. Cavin Rawlins
19. heinäkuuta 2009 klo 15:56 (GMT)
Yea, SJ I'm seeing what appears to be a LLC so that buoy info should be interesting and the TWO.
Member Since: 24.07.2005 Posts: 407 Comments: 19076
2274. WAHA
19. heinäkuuta 2009 klo 15:56 (GMT)
Quoting all4hurricanes:

but those storms were all in august except for dolly but she formed in the western Caribbean

Omar october Paloma november
2273. Drakoen
19. heinäkuuta 2009 klo 15:56 (GMT)
Quoting Grothar:
Thanks to all for the answers on the SAL. Since I am a novice to this blog, I shall probabaly ask more questions, than provide opinions. Hope no one minds. There has been mention of a trough over SE U.S. Does anyone have any idea as to the effect, if any, it may have on the direction of ANY systems which approach the Caribbean? If I am correct, the current models indicate a more southerly track. Also, please excuse me my writing, since English is not my first language.


Your syntax, diction, and grammar is better than a lot here lol.
Member Since: 28.10.2006 Posts: 57 Comments: 29714
2272. STORMMASTERG
19. heinäkuuta 2009 klo 15:56 (GMT)
Quoting jurakantaino:
Dr. Lyons did his best to avoid mentioning the "invest", his words:" In the Mean time there is another wave approaching the island that will bring a couple of showers to the antilles"
Plus upper winds are not favorable for formation further west/twc is a channel of no reliability,they only make you seem to think that.
2271. AussieStorm
19. heinäkuuta 2009 klo 15:55 (GMT)
Wx Update, E Caribbean, Sat18, 9a

Morning graphical QuickScat: ABCs & Venezuela W of 66W ENE-E@13-20 with a few squalls to 35k, mainly N of 12N / E of 66W to Trinidad & Grenada E@0-10 with isolated squalls to 30k / just W of Windwards ENE-E@10-17 / W of Leewards ENE@16-22 with scattered squalls to 30k / Virgins & PuertoRico ENE@15-20 / DomRep ENE-E@12-17.



TropicalWAVE near 60W:
--Strong, high-amplitude WAVE near E Caribbean along 17N/59W...12N/63W, moving W-WNW@15. To gauge risk for Tropical LO formation, I look for the following 3 criteria: squalls that are abundant, focused, and persistent at the focal point. This morning, squalls have become more-abundant & focused at 16N/59W. If these squalls persist over the next 12-24 hrs, a Tropical LO could form.

--Typically, such squall activity surges & wanes several times before becoming persistent-enough to generate a self-sustaining Tropical LO. Thus, it is unlikely (but not impossible - I'd estimate a 10% chance) a LO will form before this area moves W of VirginIslands & PuertoRico tomorrow. Wind-shear of 40-50k is decreasing, but should help prevent formation of a Tropical LO.

--NOAA this morning began mentioning a low (less-than-30%) chance of Tropical LOW formation over next 48hrs with this feature.

--Beyond tomorrow, Apex of WAVE should lie somewhere near the GreaterAntilles (Hispanola & Cuba), which, combined with likelihood of persistent wind-shear, should prevent formation of a Tropical LOW.

Link
Member Since: 30.09.2007 Posts: 9 Comments: 15749
2270. Drakoen
19. heinäkuuta 2009 klo 15:54 (GMT)
Member Since: 28.10.2006 Posts: 57 Comments: 29714
2269. juniort
19. heinäkuuta 2009 klo 15:54 (GMT)
no news here in Barbados as yet
Member Since: 19.07.2009 Posts: 0 Comments: 69
2268. Grothar
19. heinäkuuta 2009 klo 15:54 (GMT)
Thanks to all for the answers on the SAL. Since I am a novice to this blog, I shall probabaly ask more questions, than provide opinions. Hope no one minds. There has been mention of a trough over SE U.S. Does anyone have any idea as to the effect, if any, it may have on the direction of ANY systems which approach the Caribbean? If I am correct, the current models indicate a more southerly track. Also, please excuse me my writing, since English is not my first language.
Member Since: 17.07.2009 Posts: 63 Comments: 23727
2267. jurakantaino
19. heinäkuuta 2009 klo 15:54 (GMT)
Dr. Lyons did his best to avoid mentioning the "invest", his words:" In the Mean time there is another wave approaching the island that will bring a couple of showers to the antilles"
Member Since: 31.07.2008 Posts: 0 Comments: 730
2266. HurricaneSwirl
19. heinäkuuta 2009 klo 15:54 (GMT)
Quoting WAHA:

Dolly, Fay, Gustav, Omar and Paloma all formed in the carribean last year.


yes but only omar could form in the east caribbean. all the others could not get started in the east caribbean. well fay did too be she wasn't particularly strong, she just was moving very slow and landfalled in florida 4 times XD
Member Since: 7.07.2008 Posts: 2 Comments: 3237
2265. moonlightcowboy
19. heinäkuuta 2009 klo 15:53 (GMT)
Quoting SavannahStorm:
lol, Dr. Lyons barely even mentioned 97L...


They're short on time, commercials and all for travel, etc. Only soundbites, like the evening news. LOL. They hardly mention anything any more unless is has been named a TD. I don't watch them anymore, consequently.
Member Since: 9.07.2006 Posts: 184 Comments: 29594
2264. DDR
19. heinäkuuta 2009 klo 15:53 (GMT)
Quoting Weather456:
I do believe we have LLC or one is forming


Lets hope it doesn't rapidly intensify,the islands will welcome the rain,thats for sure.
Member Since: 27.04.2007 Posts: 14 Comments: 1627
2263. all4hurricanes
19. heinäkuuta 2009 klo 15:53 (GMT)
Quoting WAHA:

Dolly, Fay, Gustav, Omar and Paloma all formed in the carribean last year.

but those storms were all in august except for dolly but she formed in the western Caribbean
Member Since: 29.03.2008 Posts: 0 Comments: 2338
2262. sporteguy03
19. heinäkuuta 2009 klo 15:53 (GMT)
Quoting WxLogic:


Would be funny if it has the same fate...


Actually the name "Chris" has had a history of downfalls as well, I remember Dr.M doing a blog on him in 2006.
Member Since: 7.07.2005 Posts: 0 Comments: 5120
2261. aquak9
19. heinäkuuta 2009 klo 15:53 (GMT)
2229- bam shallow for another 24-48, then a whole new ballgame. Bam mid another 24-36, then bam deep runs, maybe lgem.

Who knows, maybe GFS will sober up by then.
Member Since: 13.08.2005 Posts: 163 Comments: 25507
2260. StormJunkie
19. heinäkuuta 2009 klo 15:53 (GMT)
Morning PDoug, good to see ya.

456 - pressure has started to fall at 41040 as well. Should continue to drop as 97 approaches. It should be an interesting buoy to watch today...A fair clip north of the system, but still should provide some data.
Member Since: 17.08.2005 Posts: 26 Comments: 15472
2259. Cavin Rawlins
19. heinäkuuta 2009 klo 15:53 (GMT)
Dead zone? I often wonder where that came from especially after Felix, Charley, Omar, etc.
Member Since: 24.07.2005 Posts: 407 Comments: 19076
2258. TampaMishy
19. heinäkuuta 2009 klo 15:53 (GMT)
Quoting naplesdreamer28:
I don't like the looks of those tracks. A Charlie type tracking.
You always say that.
Member Since: 30.07.2007 Posts: 0 Comments: 1474
2257. hurricane23
19. heinäkuuta 2009 klo 15:53 (GMT)
.
Member Since: 14.05.2006 Posts: 8 Comments: 13597
2256. Drakoen
19. heinäkuuta 2009 klo 15:52 (GMT)
Quoting WxLogic:


Would be funny if it has the same fate...


I was thinking that too lol
Member Since: 28.10.2006 Posts: 57 Comments: 29714
2255. SavannahStorm
19. heinäkuuta 2009 klo 15:52 (GMT)
lol, Dr. Lyons barely even mentioned 97L...
Member Since: 22.09.2005 Posts: 18 Comments: 2229
2254. PensacolaDoug
19. heinäkuuta 2009 klo 15:51 (GMT)
Nothin like a good invest to get the blog moving at light speed.....
Member Since: 25.07.2006 Posts: 0 Comments: 519
2253. Cavin Rawlins
19. heinäkuuta 2009 klo 15:51 (GMT)
Quoting sporteguy03:


Do the Windward Islands have their own weather service that broadcasts on tropical systems about to effect them just wondering if there was any news on the invest in that region.


I'm in the Leewards but they are monitoring the disturbance.
Member Since: 24.07.2005 Posts: 407 Comments: 19076
2252. Chicklit
19. heinäkuuta 2009 klo 15:51 (GMT)
Dr. Masters promised an update this afternoon; mostly likely will appear after the 2 pm discussion.
Member Since: 11.07.2006 Posts: 14 Comments: 11047
2251. WAHA
19. heinäkuuta 2009 klo 15:51 (GMT)
Quoting PensacolaDoug:
"Ana" by this time tomorrow? Could be at the rate its spinning up now but, storms that are not very organized before getting to the eastern Carrib don't usually develope until they get to western Carrib. Eastern Carrib is usually kind of a "dead zone" for developement.
But it sure is looking impressive right now.

Dolly, Fay, Gustav, Omar and Paloma all formed in the carribean last year.
2250. WxLogic
19. heinäkuuta 2009 klo 15:51 (GMT)
Quoting all4hurricanes:

what about north of the carribean cause thats where this thing is supposed to be heading

heres an eerily similar Ana from 79


Would be funny if it has the same fate...
Member Since: 14.08.2008 Posts: 4 Comments: 4881

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About JeffMasters

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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