Lesser Antilles may see a tropical storm late this week

By: Dr. Jeff Masters , 1. elokuuta 2010 klo 13:51 (GMT)

Share this Blog
3
+

A concentrated area of intense thunderstorms near 9N 36W, midway between Africa and the Lesser Antilles Islands, has become more organized this morning. NHC has labeled this system Invest 91L, and is giving it a 60% chance of developing into a tropical depression by 8am Tuesday. Wind shear is a moderate 10 - 20 knots, sea surface temperatures are at record highs, and the dust and dry air of the Saharan Air Layer (SAL) are far enough to the north of 91L to potentially allow further development. The main negatives for development are the current phase of the Madden-Julian Oscillation, which favors downward motion over the tropical Atlantic, and the fact that 91L is too close to the Equator to take much advantage of the Earth's spin to get spinning. Last night's ASCAT pass of the region did show a large region of westerly winds south of 91L, indicating that a surface circulation is trying to form. Satellite imagery shows that the intensity and areal extent of 91L's heavy thunderstorms is increasing. However, there are no signs of a surface circulation, and low-level spiral bands and upper-level outflow are not apparent yet.

Forecast for 91L
There is strong model support for 91L developing into a tropical depression. The GFS, ECMWF, NOGAPS, and UKMET models all develop 91L into a tropical depression by Tuesday or Wednesday. A west to west-northwest motion is predicted, and residents of the Lesser Antilles Islands should anticipate the possibility of a tropical storm arriving in the islands as early as Thursday. It is possible that 91L would pass northeast of the islands, as predicted by the UKMET model, and it is too early to speculate on which of the islands is at most risk. As the storm approaches the Lesser Antilles late this week, 91L will encounter a strong upper-level low pressure system centered north of Puerto Rico. This upper-level low will likely bring high levels of wind shear to the waters just north of Puerto Rico and Hispaniola. Thus, if 91L stays to the south, in the Caribbean, it is far more likely to attain hurricane status than if it pushes north of the Caribbean. As always, long range forecasts of this sort are speculative, and it is too early to reliably say what the long-term risks of 91L becoming a hurricane are. The latest intensity forecast from the SHIPS model shows 91L peaking in strength four days from now, then weakening as it encounters the high wind shear area north of Puerto Rico.


Figure 1. Morning satellite image of Invest 91L.

Next update
I'll have an update Monday morning.

Jeff Masters

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 4077 - 4027

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82Blog Index

4077. Laughingmomma
8. elokuuta 2010 klo 19:15 (GMT)
I have a paid membership and got the same Norton warning about "unsafe site" related to (and I quote:) Threat Report
Total threats found: 3


Embedded Link To Malicious Site (what's this?)
Threats found: 2
Here is a complete list:

Threat Name: Embedded link to malicious site wunderground.com
Location: http://www.wunderground.com/US/TX/Amarillo.html



Threat Name: Embedded link to malicious site wunderground.com
Location: http://www.wunderground.com/US/TN/Oak_Ridge.html




Viruses (what's this?)
Threats found: 1
Here is a complete list:

Threat Name: Adware.ADH
Location:

my live in computer guy is going to scan for malware now!
4076. bammbamm2020
3. elokuuta 2010 klo 01:18 (GMT)
Can someone tell me the origin of the word "Invest", as it relates to the name of an atmospheric disturbance?
4075. hydrus
2. elokuuta 2010 klo 17:29 (GMT)
Quoting Dakster:
I noticed that "TD4" is out... I also noticed that the NHC doesn't expect this to make it to Hurricane status... Everyone here agree?
T.D. 4 will make hurricane status.jmo
Member Since: 27.09.2007 Posts: 1 Comments: 19504
4073. wunderkidcayman
2. elokuuta 2010 klo 15:14 (GMT)
ok now we have TD4 now I just wait until its at 45-50W then see what the models say
Member Since: 13.06.2009 Posts: 2 Comments: 9549
4072. Dakster
2. elokuuta 2010 klo 14:38 (GMT)
I noticed that "TD4" is out... I also noticed that the NHC doesn't expect this to make it to Hurricane status... Everyone here agree?
Member Since: 10.03.2006 Posts: 0 Comments: 9689
4071. cirrocumulus
2. elokuuta 2010 klo 14:34 (GMT)
Holy smokes! Look at all the energy coming into 91L from the east. It looks like another batch of moisture reaching 32W.
Member Since: 30.09.2005 Posts: 0 Comments: 1606
4070. StormChaser81
2. elokuuta 2010 klo 14:30 (GMT)
Quoting whs2012:
Can this storm make it into the gulf of mexico?


Is water wet.

Anything is possible.

Wait 8 to 10 days and see what happens.
Member Since: 11.08.2008 Posts: 0 Comments: 2315
4069. Chicklit
2. elokuuta 2010 klo 14:28 (GMT)
NEW BLOG
Member Since: 11.07.2006 Posts: 14 Comments: 11034
4068. BadHurricane
2. elokuuta 2010 klo 14:27 (GMT)
Quoting whs2012:
Can this storm make it into the gulf of mexico?


Of course it can!
Member Since: 5.12.2008 Posts: 0 Comments: 59
4067. truecajun
2. elokuuta 2010 klo 14:26 (GMT)
Quoting whs2012:
Can this storm make it into the gulf of mexico?


yes, it's definitely possible
Member Since: 24.08.2006 Posts: 0 Comments: 1867
4066. truecajun
2. elokuuta 2010 klo 14:25 (GMT)
i think there is a new blog
Member Since: 24.08.2006 Posts: 0 Comments: 1867
4065. DaytonaBeachWatcher
2. elokuuta 2010 klo 14:25 (GMT)
FNMOC Satellite Data Tropical Cyclone Page

2010 Storms
All Active Year


Atlantic
04L.FOUR

East Pacific

Central Pacific
92C.INVEST

West Pacific
96W.INVEST

Indian Ocean

Southern Hemisphere

Member Since: 29.06.2007 Posts: 0 Comments: 1135
4063. StormChaser81
2. elokuuta 2010 klo 14:25 (GMT)
Quoting Chicklit:
Re #4059: Is the center moving SSE?


Looks like the computer is having center location problems. Center is still west bound.
Member Since: 11.08.2008 Posts: 0 Comments: 2315
4062. DaytonaBeachWatcher
2. elokuuta 2010 klo 14:24 (GMT)
al four on the old navy site
Member Since: 29.06.2007 Posts: 0 Comments: 1135
4061. Chicklit
2. elokuuta 2010 klo 14:22 (GMT)
Re #4059: Is the center moving SSE? Or are things just shifting around because there is no real center yet?
Member Since: 11.07.2006 Posts: 14 Comments: 11034
4060. truecajun
2. elokuuta 2010 klo 14:18 (GMT)
so i was reading dr. m's update to a friend yesterday, and she wondered what the lesser antilles were. i'm sure most of us on here know the whole greater, lesser (leeward, windward), but I certainly didn't learn it in school. It wasn't until i was interested in storms that i figured it out. so in case any newbies are wondering....

The Greater and Lesser Antilles are south of the Bahamas. the Greater Antilles are made up of the "big islands" of Cuba, Jamaica, Hispaniola (Haiti and Dominican Republic), and Puerto Rico.

The "small islands" make up the Lesser Antilles. The Lesser Antilles are divided into the Leeward Islands (the northern half) and the Windward Islands (the southern half)

the prevailing winds are south, so that's how they got the name windward.
Member Since: 24.08.2006 Posts: 0 Comments: 1867
4059. cirrocumulus
2. elokuuta 2010 klo 14:17 (GMT)
Member Since: 30.09.2005 Posts: 0 Comments: 1606
4058. scott39
2. elokuuta 2010 klo 14:13 (GMT)
Quoting weatherguy03:
Latest Video Blog On Invest 91L
Thanks your video on invest 91L
Member Since: 13.06.2009 Posts: 0 Comments: 6706
4057. GetReal
2. elokuuta 2010 klo 14:12 (GMT)




In difference to those early model runs, the steering looks more westward over the next 72 hours....
Member Since: 4.07.2005 Posts: 204 Comments: 8802
4056. psuweathernewbie
2. elokuuta 2010 klo 14:12 (GMT)
While most of the convection has dissipated with 91L, the convection it has left is over its coc, which means an organizing system is taking place. It would seem with the ASCAT pass Drakeon showed it is still rather disorganized which is a little strange. Last night the upper level winds CIMSS showed that the upper level anticyclone was strengthening over 91L. Also equatorward outflow channel is finding it hard to develop, but slowly and surely it is, as well as a potential poleward channel. Also it is far and above that ITCZ now and the convection is sustaining as well as creating its own convection which is great news for becoming a tropical cyclone soon.
4055. GeoffreyWPB
2. elokuuta 2010 klo 14:12 (GMT)
invest_RENUMBER_al912010_al042010.ren
Member Since: 10.09.2007 Posts: 0 Comments: 10577
4054. oracle28
2. elokuuta 2010 klo 14:12 (GMT)
Quoting WildWillyFL:


Are you going to believe the models or your lying eyes?


There ain't no way to hide your lying eyes.
Member Since: 25.07.2008 Posts: 0 Comments: 596
4053. KEEPEROFTHEGATE (Mod)
2. elokuuta 2010 klo 14:11 (GMT)
X
Member Since: 15.07.2006 Posts: 163 Comments: 52216
4052. Chicklit
2. elokuuta 2010 klo 14:11 (GMT)
Re: #4039 ...right. the P word.
Member Since: 11.07.2006 Posts: 14 Comments: 11034
4051. AstroHurricane001
2. elokuuta 2010 klo 14:11 (GMT)
Quoting ncforecaster:
Hey everyone...I only have just a minute to make a very quick post. In doing so, I just wanted to explain that the NHC doesn't typically designate a tropical disturbance as a TC until the convection consolidated around the COC has persisted for at least a period of 6 hours.

This has been the general rule of thumb since way back when I did my second student internship there in 1994. That is why it may appear to some that the NHC is too conservative in initiating TC advisories.

With the aforementioned in mind, the NHC may designate 91L as TD #4 by the 11 am EDT advisory.

Well, I gotta go-but want to wish each one of you a great rest of the day!:)


Darn it, by the it's going to have an eye.
Member Since: 30.08.2008 Posts: 8 Comments: 2834
4050. ho77yw00d
2. elokuuta 2010 klo 14:11 (GMT)
Quoting Relix:

Seems like you are gonna be surfing and I I may be doing some storm hunting =P
Ugh. The models are already off by a few miles they are gonna shit west and south. There are many factors and I would value StormW's, Levy's, 456's and Drakoen's input more than what the models are showing. The models are wrong right now



lmao..spell check ;0)
Member Since: 3.07.2010 Posts: 0 Comments: 427
4049. stormwatcherCI
2. elokuuta 2010 klo 14:10 (GMT)
Relix, re-read your post 4025 and edit. LOL
Member Since: 9.10.2008 Posts: 0 Comments: 8242
4048. hurricanemaniac123
2. elokuuta 2010 klo 14:10 (GMT)
NEW BLOG!
Member Since: 21.09.2008 Posts: 9 Comments: 688
4047. MTWX
2. elokuuta 2010 klo 14:10 (GMT)
Quoting Cotillion:


I think you see a fair few in Eastern Europe, Russia type area.

But considering they attempt to select only from Germanic, Francophonic and Hispanophonic names, you can tell they're running out of ideas.



Sponsored tropical systems. Don't give marketing departments ideas.

What you do is just make them responsible for the damages of their sponsored storm.
Member Since: 20.07.2009 Posts: 23 Comments: 1391
4046. Sfloridacat5
2. elokuuta 2010 klo 14:10 (GMT)
New blog
Member Since: 16.09.2007 Posts: 0 Comments: 4734
4045. FloridaHeat
2. elokuuta 2010 klo 14:10 (GMT)
Quoting tropicfreak:


It looks like 91L is really getting its act together. Nice ball of strong convection right around the center too. Very impressed. Now we will see what the NHC says at 11am.


i have researched this some but it appears the nhc updates every 3 hours sometimes and then every 6 hours other times why the difference???
Member Since: 31.07.2010 Posts: 0 Comments: 357
4044. HurricaneSwirl
2. elokuuta 2010 klo 14:10 (GMT)
Quoting Drakoen:
ASCAT pass just came in revealing that 91L's surface circulation is poorly organized.



Looks very possible that they don't initiate advisories at 11.. 5PM looking like our best bet. Still got like 20 minutes for that renumber.. but then again Bonnie never got a renumber (but she got a special TWO, 91L so far has neither).
Member Since: 7.07.2008 Posts: 2 Comments: 3237
4042. earthlydragonfly
2. elokuuta 2010 klo 14:09 (GMT)
Member Since: 1.07.2005 Posts: 10 Comments: 1681
4041. angrypartsguy
2. elokuuta 2010 klo 14:09 (GMT)
whats going on in the blog today peeps
Member Since: 9.04.2010 Posts: 5 Comments: 4589
4040. IKE
2. elokuuta 2010 klo 14:09 (GMT)
Quoting weatherguy03:
Latest Video Blog On Invest 91L


I hadn't even looked at the SAL...

Agree that dry air is affecting it.
Member Since: 9.06.2005 Posts: 23 Comments: 37858
4039. ncforecaster
2. elokuuta 2010 klo 14:08 (GMT)
Hey everyone...I only have just a minute to make a very quick post. In doing so, I just wanted to explain that the NHC doesn't typically designate a tropical disturbance as a TC until the convection consolidated around a well-defined COC has persisted for at least a period of 6 hours.

This has been the general rule of thumb since way back when I did my second student internship there in 1994. That is why it may appear to some that the NHC is too conservative in initiating TC advisories.

With the aforementioned in mind, the NHC may designate 91L as TD #4 by the 11 am EDT advisory.

Well, I gotta go-but want to wish each one of you a great rest of the day!:)
Member Since: 17.05.2006 Posts: 105 Comments: 1350
4038. Goldenblack
2. elokuuta 2010 klo 14:08 (GMT)
Pretty telling image....

Quoting Drakoen:
ASCAT pass just came in revealing that 91L's surface circulation is poorly organized.

Member Since: 28.06.2010 Posts: 0 Comments: 706
4037. tropicfreak
2. elokuuta 2010 klo 14:08 (GMT)


It looks like 91L is really getting its act together. Nice ball of strong convection right around the center too. Very impressed. Now we will see what the NHC says at 11am.
Member Since: 2.09.2006 Posts: 110 Comments: 6814
4035. divdog
2. elokuuta 2010 klo 14:06 (GMT)
Quoting JLPR2:


haha! yeah LOL
Maybe they are waiting to see if 91L will continue to shrink into nothing XD
or maybe they want more organization. did u just look at the ascat pass drakeon just posted
Member Since: 22.08.2008 Posts: 0 Comments: 755
4034. AstroHurricane001
2. elokuuta 2010 klo 14:06 (GMT)
Quoting Drakoen:


It appears the system is trying to establish poleward banding supported by an upper level high.

I'm not sure what low level clouds you are referring to...coordinates?




14N, 45W
19N, 47W
24N, 45W
29N, 39W
34N, 34W
Member Since: 30.08.2008 Posts: 8 Comments: 2834
4033. serialteg
2. elokuuta 2010 klo 14:05 (GMT)
Quoting Patrap:


can i get some movement with that?
Member Since: 22.08.2006 Posts: 2 Comments: 1975
4032. ho77yw00d
2. elokuuta 2010 klo 14:04 (GMT)
Quoting WeatherNerdPR:

IT'S DANIELLE.



stop saying my name...lol
Member Since: 3.07.2010 Posts: 0 Comments: 427
4031. JLPR2
2. elokuuta 2010 klo 14:04 (GMT)
Quoting Chicklit:

Coffee break?


haha! yeah LOL
Maybe they are waiting to see if 91L will continue to shrink into nothing XD
Member Since: 4.09.2007 Posts: 7 Comments: 8459
4029. Drakoen
2. elokuuta 2010 klo 14:03 (GMT)
ASCAT pass just came in revealing that 91L's surface circulation is poorly organized.

Member Since: 28.10.2006 Posts: 57 Comments: 29714
4028. WildWillyFL
2. elokuuta 2010 klo 14:02 (GMT)
Quoting leo305:
The models are taking it too far to the north..

the system is already moving south of their points


Are you going to believe the models or your lying eyes?
Member Since: 18.08.2008 Posts: 0 Comments: 34
4027. tropicfreak
2. elokuuta 2010 klo 14:02 (GMT)
They only send out recon if land impacts are very likely within the next 2 days. And in this scenario, its a 50/50 for the lessler antillies.
Member Since: 2.09.2006 Posts: 110 Comments: 6814

Viewing: 4077 - 4027

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82Blog Index

Top of Page

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.

Local Weather

Partly Cloudy
62 °F
Puolipilvistä