An Atlantic tropical wave worth watching

By: Dr. Jeff Masters , 2:46 PM GMT on October 04, 2009

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A large tropical wave near 9N 40W, midway between Africa and the Lesser Antilles Islands, is generating a considerable amount of heavy thunderstorm activity as it moves west to west-northwest at 15 mph. The wave is under about 10 - 15 knots of wind shear, and this morning's QuikSCAT pass showed a large and disorganized region of converging winds in the region, with top winds of 25 mph. There is very little dry air in the vicinity, and conditions appear favorable for some slow development of this wave. None of the computer models develop the wave, but they do show relatively low wind shear along the wave's path for the next five days. The wave should reach the Lesser Antilles Islands by Wednesday.


Figure 1. The large tropical wave in the middle Atlantic.

In the Philippines, Tropical Storm Parma continues to linger offshore the northern tip of the Philippines' Luzon Island, bringing heavy rain. The storm has been blamed for the deaths of 17 people in the Philippines, but has not not had the devastating impact that was earlier feared. Parma's heaviest rains will stay offshore of the Philippines today (Figure 2).


Figure 2. Forecast rain amounts for Parma for the 24-hour period ending at 06 UTC October 5 (2am EDT Monday). This forecast is based on satellite measurements of Parma's current rainfall rate, plus a projection of the storm's path. Four to eight inches of rain (yellow colors) is expected along the extreme northwest tip of Luzon Island. Image credit: NOAA Satellite Services Division.

Super Typhoon Melor hits Cat 5 strength
Super Typhoon Melor has become the second Category 5 tropical cyclone of the year. Melor is expected to recurve to the north pass just south of the coast of Japan later this week.

Jeff Masters

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89. Skyepony (Mod)
Quoting lawntonlookers:
Thanks for the update Dr. Masters

Could someone that is familiar with CloudSat go the link below and check out the image 18273FL and see if that is a pass through part of Melar. I think it is but just want another opinion.

CLOUDSAT


Good catch especially without modis on that pass..Down the left sida. Here's that pass with mtsat for perspective..
http://www.latimes.com/news/local/la-me-alpaca24-2009sep24,0,877168.story width=550>
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85. IKE
12Z CMC


Big trough in the east on the 12Z NOGAPS.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
JRRP - Captain, raise the shear shield over Eastern CONUS... Aye Aye, Captain...

Member Since: March 10, 2006 Posts: 0 Comments: 10251
82. JRRP

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Thanks For The Update Dr. Masters!

- Bryant
TarHeelWeather.com
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Never seen the Atlantic & Caribbean so convective in along time & maintaining it.
Member Since: April 29, 2007 Posts: 0 Comments: 7862
79. IKE
If you live in the eastern USA, get ready for a strong trough to take over by this time next Sunday according to the 12Z GFS...

It takes the wave the NHC is mentioning, to the NE Carribean sea and losses it. Similar to the 00Z ECMWF.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting Weather456:


What I really mean is potential for development over the next 5 days is there.


Got Cha....Enjoy your analysis and out now for Sunday chores. See everyone and the wave tommorow.....Have a Great Day Folks. WW
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Quoting weathermanwannabe:


So are you thinking a possible rain event for the Antilles, but, the possibility of development after it passes the Antilles in the Eastern Caribbean?


What I really mean is potential for development over the next 5 days is there.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:


Very true, what I'm more concern/interested in is beyond 3 days when shear looks like this:



So are you thinking a possible rain event for the Antilles, but, the possibility of development after it passes the Antilles in the Eastern Caribbean?
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Quoting weathermanwannabe:
The University of Wisconsin Cooperative Institute for Meteorological Studies (UW-CIMSS) computes high-resolution satellite-derived wind vectors globally using geostationary satellite imagery. UW-CIMSS has
automated a process to derive vertical wind shear using this wind information (Gallina and Velden 2000) and is providing these fields in real-time via the Internet


The current CIMSS sheer tendancy analysis shows decreasing sheer right around the location of the wave but increasing sheer as it approaches the Antilles above about 15N. Seems to me that a possible window of opportunity to get it's act together is right now, but, if it gains much latitude over the next two days, sheer may prevent tropical development........I agree with the low chance for development from NHC at present unless some significant organization occurs by this time tommorow.


Very true, what I'm more concern/interested in is beyond 3 days when shear looks like this:

Member Since: July 24, 2005 Posts: 407 Comments: 19076


aidos cape verde season till we meet in 2010
Member Since: July 15, 2006 Posts: 171 Comments: 53774
The University of Wisconsin Cooperative Institute for Meteorological Studies (UW-CIMSS) computes high-resolution satellite-derived wind vectors globally using geostationary satellite imagery. UW-CIMSS has
automated a process to derive vertical wind shear using this wind information (Gallina and Velden 2000) and is providing these fields in real-time via the Internet


The current CIMSS sheer tendancy analysis shows decreasing sheer right around the location of the wave but increasing sheer as it approaches the Antilles above about 15N. Seems to me that a possible window of opportunity to get it's act together is right now, but, if it gains much latitude over the next two days, sheer may prevent tropical development........I agree with the low chance for development from NHC at present unless some significant organization occurs by this time tommorow.
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What kinda boat are you sailingallover?
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This just sends chills down your spine imagining it in the Atlantic.

Maximum winds of 140 knots
Gusts to 170 knots
290 degrees at 16 knots

Latitude: 17.5
Longitude: 139.3
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Weather456 THANKS...
That is exactly what I wanted to see...
Member Since: September 1, 2009 Posts: 23 Comments: 1007
Please check out post # 50 in the Portlight featured WU blog...I'd like your thoughts...also, there's a picture of the Baxters' flood damaged home which is truly worth a thousand words...Thanks!

Link
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Orca, turning back east now..
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Quoting sailingallover:
PR radar does not go that far...only about to St Maarten.
With no quickscat and no radar hard to tell what happening under those clouds..

Does look like it's dying down now but this morning the convection took off..
http://www.ssd.noaa.gov/goes/east/carb/loop-avn.html


LINK

Member Since: July 24, 2005 Posts: 407 Comments: 19076
StormChaser, you have mail
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting btwntx08:
i say 2100z an invest
agreed
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Quoting wunderkidcayman:

so maybe 18z
That is 2PM. i think more like 00z or 06z.
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Post 56 and 57,

Dr. Steve Lyons has access to the same models I use and Dr. Masters used and he knows shear is expected to relax but when he started his tropical update this what he said "A few regions of showers across the Caribbean that will may ruin your vacation plans for a few hours."

I hate TWC and I hate how they have a respectful met as Mr. Lyons, bold facedly watching me and telling me shear is expected to increase along the path. I would not be surprise if in the next hr he comes back on and change his mind, it has happen many times in the past where you went from it will develop to it won't develop in the same hr.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
PR radar does not go that far...only about to St Maarten.
With no quickscat and no radar hard to tell what happening under those clouds..

Does look like it's dying down now but this morning the convection took off..
http://www.ssd.noaa.gov/goes/east/carb/loop-avn.html
Member Since: September 1, 2009 Posts: 23 Comments: 1007
Quoting btwntx08:

no give it the rest of the day aleast

so maybe 18z
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Quoting sailingallover:
That feature at 61W 18N is really bothering me.. Does anybody have a site with the low level winds for the last few hours? Looks like it has starting really organizing from sat pics.
Yes we have shear..we also have 30C water and it is still a historically very active time of the season.

I'm in St Thomas with my boat and think of going into the hurricane hole just to be safe...

NOAA is at thier Sunday afternoon picnic as usual. The last Puerto Rice discussion update is from 5AM.
Check the Puertor Rico radar,Link
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Quoting BahaHurican:
Fore the third time of trying...

Morning, Everybody.

Ho, no! U won't catch me with that innocuous "chuckle"! Last time I did that I had a sore diaphram for days....

Looks like Melor was only waiting to get out from under Parma's influence before blowing up. BTW, anybody with SST link to that area of the WPac? Ta in advance...


These are rather old though.

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Quoting Weather456:
Dr. Lyons say wind shear is going get less favorable.



is that accurate?
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Quoting Weather456:
Dr. Lyons say wind shear is going get less favorable.

so what do you believe more or less
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Sorry, folks. My internet connection has been freaked out since Friday afternoon... sometimes it works, sometimes it...does something else.

I did want to ask if anyone thinks that Twave will hang around long enough to pick up on the MJO upswing later this month. I'd expect it to get into the EPac and maybe do something there, myself....
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Quoting BahaHurican:
Fore the third time of trying...

Morning, Everybody.

Ho, no! U won't catch me with that innocuous "chuckle"! Last time I did that I had a sore diaphram for days....

Looks like Melor was only waiting to get out from under Parma's influence before blowing up. BTW, anybody with SST link to that area of the WPac? Ta in advance...


ROFLMAO, it started with an innocent joke in the comments at #17 when the blog was slow.. and has gone nuts ever since.

Now that we finally have a Blob to look at.. it might slow down.

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Quoting Weather456:
Dr. Lyons say wind shear is going get less favorable.


Some pretty hefty shear to the north.

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Dr. Lyons say wind shear is going get less favorable.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Stormchaser2007:
For this to become an invest it would just need to persist for a little while more.


ok Invest 91L by 12
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Fore the third time of trying...

Morning, Everybody.

Quoting Orcasystems:

AOI

AOI

AOI

AOI

If you need a morning chuckle, check the comments section :)
Ho, no! U won't catch me with that innocuous "chuckle"! Last time I did that I had a sore diaphram for days....

Looks like Melor was only waiting to get out from under Parma's influence before blowing up. BTW, anybody with SST link to that area of the WPac? Ta in advance...
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Quoting Stormchaser2007:
For this to become an invest it would just need to persist for a little while more.



yea, and consolidate
Member Since: July 24, 2005 Posts: 407 Comments: 19076
For this to become an invest it would just need to persist for a little while more.

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Quoting Weather456:


Now we wait for someone to kill it. This is as much tropical as it has gotten 'round these parts. Doing my analysis this morning, it was like "I haven't done this in a while"

...
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Quoting jurakantaino:
Dr Masters said none of the models develope this wave right now. If im looking at it right the CMC does. Am i right or wrong? No, you are right JLPR, was talked about it , last night.

yep yesterday I posted it
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Quoting sailingallover:
That feature at 61W 18N is really bothering me.. Does anybody have a site with the low level winds for the last few hours? Looks like it has starting really organizing from sat pics.
Yes we have shear..we also have 30C water and it is still a historically very active time of the season.

I'm in St Thomas with my boat and think of going into the hurricane hole just to be safe...

NOAA is at thier Sunday afternoon picnic as usual. The last Puerto Rice discussion update is from 5AM.
that area is waning out just high clouds thinning out unless new convection fires soon its all blowing away in shear
Member Since: July 15, 2006 Posts: 171 Comments: 53774
Quoting wunderkidcayman:
well now the blog is up and running i am happy


Now we wait for someone to kill it. This is as much tropical as it has gotten 'round these parts. Doing my analysis this morning, it was like "I haven't done this in a while"
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting sailingallover:
That feature at 61W 18N is really bothering me.. Does anybody have a site with the low level winds for the last few hours? Looks like it has starting really organizing from sat pics.
Yes we have shear..we also have 30C water and it is still a historically very active time of the season.

I'm in St Thomas with my boat and think of going into the hurricane hole just to be safe...

NOAA is at thier Sunday afternoon picnic as usual. The last Puerto Rice discussion update is from 5AM.


No closed circulation just turning. The interaction with dry air is making it look like "an expose LLC"

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Dr Masters said none of the models develope this wave right now. If im looking at it right the CMC does. Am i right or wrong? No, you are right JLPR, was talked about it , last night.
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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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