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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Quoting kmanislander:
That's weird. When I first looked at the QS pass half the data was missing but the link I posted now shows a full download of data. LOL
You notice the small area south of Jamaica ? Anything there ?
Member Since: October 9, 2008 Posts: 0 Comments: 8393
10N 46W seems to be the focal point for the surface low pressure with that wave.
Member Since: August 19, 2006 Posts: 0 Comments: 15842
Quoting kmanislander:
That's weird. When I first looked at the QS pass half the data was missing but the link I posted now shows a full download of data. LOL


I saw that too
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting kmanislander:


Hi there,

yeah, Thursday was wild and this morning lots of thunder and lightning between 7 and 9 a.m. but the day cleared up real nice. Got my golf game in so I am a happy camper LOL

well at least we got a welcoming soaking in west bay
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Quoting jipmg:
I don't understand, why isn't the low near the Azores a sub tropical storm?


As you guys may know, we have been debating this all weekend long




Quoting Cazatormentas:
Evening all from Spain :)

Does anyone know what area consider cyclone phase diagrams? I'm sure the extratropical low of Azores has developed a well separated tropical engine perturbation... Despite its origin and despite of those cyclone phase diagrams.

Thanks! :D


Hola,

you might want to read this;

Also someone else from Spain sent me this image and was wondering why the NHC failed to mentioned it

This 90L Today, Sunday 4 October


""[The National Hurricane center] seems to be naming a lot more than they used to. This year, I would put four storms in the very questionable category, and maybe even six. In the past, we would have waited to see if another observation supported naming the system. We would have been a little more conservative."

Neil Frank, National Hurricane Center Director, 1974-1987.

1. Aren't occluded lows a characteristic of mid-latitude cyclones and don't subtropical cyclones have characteristics of both tropical and mid-latitude systems, which has fronts.

2. Aren't occluded lows the sign of a decaying mid-latitude system.

3. Does the satellite presentation support this feature being tied to a front.

4. Is there a temperature contrast along 90L, the last time I check occluded lows have uniformed temperatures.

4. Subtropical cyclones have some sort of frontal feature to their NW.

5. QS showed the strongest winds near a very well define LLCC.


Systems near Greenland as I said before have warm-cores but they are not subtropical or tropical becuz they have more non-tropical features than tropical. For one, they are baroclinic.

You cannot use 23C to define a line, there is no line when it comes to classifying systems because not all systems are perfect. For instant, a tropical depression does not have specific winds of 30, 33, 36 mph, its either 25, 30 or 35 mph. And to say SSTs were too cold when it was 22C is an exaggeration, what is the biggest difference between 22 and 23C when the system is producing convection as if it was over 24C?

So how come Vince was classified over 23C, isn't the threshold for tropical systems 26C?

I am seeing comments about water is too cold and such and that really the only argument against 90L-ex. Now tell me, if the waters are too cold why is the system produce convection? You know what those cirrus clouds indicate? Those cirrus clouds indicate air is hitting the tropopause and has no where to go but outward (outflow). Mid-latitude systems don't have convective clouds that extend that far up that's why thunderstorm frequency drops dramatically in the high lats.

Another thing, the lapse rate, if the SSTs are that cool then the air directly above the sea surface should be cooler than the air aloft (temperating rising with height is a stable situation). The only way this system could produce such organize convection on each frame for 6 hrs, is if the lapse rate was decreasing with height (unstable situation), and in order for that to happen SSTs have to be warmer than the air aloft.

Some of my co-workers who have much more experienced than I am are dumb-founded as to why the NHC has not mentioned this system today. Something is not adding up and the last time I check I haven't had any mental problems, lol. This is utterly whack!

Member Since: July 24, 2005 Posts: 407 Comments: 19076
That's weird. When I first looked at the QS pass half the data was missing but the link I posted now shows a full download of data. LOL
Member Since: August 19, 2006 Posts: 0 Comments: 15842
Quoting presslord: if I had a nickel for everytime I've heard that

lol.....i recall a line in a W.C. Fields movie where a young girl looking at Fields said, "If that nose was full of nickels he'd be a rich man." His nose was big, and sort of red, or orange, about the color I thought we'd see here from the NHC.
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Quoting kmanislander:


Hi there,

yeah, Thursday was wild and this morning lots of thunder and lightning between 7 and 9 a.m. but the day cleared up real nice. Got my golf game in so I am a happy camper LOL
East End poured from around 3 am until maybe 7/7:30 this morning and lots of thunder and lightning.
Member Since: October 9, 2008 Posts: 0 Comments: 8393
90L still has that eye.
Member Since: August 9, 2009 Posts: 10 Comments: 5026
Quoting stormwatcherCI:
I was wondering where you were lately. Thought you might have been off island. CATL looking pretty good tonight. Boy, that was some weather Thursday afternoon. What a mess,eh ?


Hi there,

yeah, Thursday was wild and this morning lots of thunder and lightning between 7 and 9 a.m. but the day cleared up real nice. Got my golf game in so I am a happy camper LOL
Member Since: August 19, 2006 Posts: 0 Comments: 15842
529. jipmg
I don't understand, why isn't the low near the Azores a sub tropical storm?
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Quoting kmanislander:


I do not pay attention to models at this stage of a system. Just looked at Quikscat.

Not sure what happened to the data swath.


very real.
Member Since: July 24, 2005 Posts: 407 Comments: 19076


umm hurricane????
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probly just another naked swirl
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Guess who's back?
Member Since: August 9, 2009 Posts: 10 Comments: 5026
523. jipmg
Quoting Weather456:
Yellow isn't a surprise, that's the way the NHC been operating this yr.


yes
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Finally, the NHC, mention the low near Azores....!!
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Member Since: Posts: Comments:
SHOWER ACTIVITY HAS INCREASED NEAR THE CENTER OF A NON-TROPICAL
LOW PRESSURE AREA LOCATED ABOUT 225 MILES NORTHEAST OF THE AZORES
ISLANDS. THIS LOW IS MOVING QUICKLY NORTHEASTWARD TOWARD COOLER
WATERS AND DEVELOPMENT INTO SUBTROPICAL OR TROPICAL CYCLONE IS NOT
LIKELY. THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS
SYSTEM BECOMING A SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT
48 HOURS.


Too late guys, they must of gotten my email late, damn yahoo.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:


Hey, many already doubted this system becuz no models support.


I do not pay attention to models at this stage of a system. Just looked at Quikscat.

Not sure what happened to the data swath.
Member Since: August 19, 2006 Posts: 0 Comments: 15842
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Yellow isn't a surprise, that's the way the NHC been operating this yr.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
all who said yellow is the winner congrats
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Quoting presslord:
...it's probably the remnants of Fred...


or Karen
Member Since: June 28, 2006 Posts: 25 Comments: 8360
513. IKE
Quoting IKE:
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT SUN OCT 4 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A TROPICAL WAVE LOCATED ABOUT 1200 MILES EAST OF THE WINDWARD
ISLANDS IS PRODUCING A LARGE AREA OF DISORGANIZED SHOWERS AND
THUNDERSTORMS. SOME SLOW DEVELOPMENT OF THIS SYSTEM IS POSSIBLE
OVER THE NEXT COUPLE OF DAYS AS IT MOVES WESTWARD AT 15 TO 20 MPH.
THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

SHOWER ACTIVITY HAS INCREASED NEAR THE CENTER OF A NON-TROPICAL
LOW PRESSURE AREA LOCATED ABOUT 225 MILES NORTHEAST OF THE AZORES
ISLANDS. THIS LOW IS MOVING QUICKLY NORTHEASTWARD TOWARD COOLER
WATERS AND DEVELOPMENT INTO SUBTROPICAL OR TROPICAL CYCLONE IS NOT
LIKELY. THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS
SYSTEM BECOMING A SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT
48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BROWN


Less than 30%....and now 90L again....on the TWO...OMG....

***pops valium***
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Quoting kmanislander:
Good evening everyone.

I have not been on for quite some time due to quiet conditions out in the basin.

The CATL feature has improved during the day and is the best thing we have seen for weeks. Right now it is benefitting from diffluent conditions aloft which are helping to ventilate the system. While still not ideal they are the best we have seen out there in weeks.

Convection is on the increase this evening so I would expect the NHC to go to orange sometime between tonight and early tomorrow morning.
I was wondering where you were lately. Thought you might have been off island. CATL looking pretty good tonight. Boy, that was some weather Thursday afternoon. What a mess,eh ?
Member Since: October 9, 2008 Posts: 0 Comments: 8393
Quoting kmanislander:


I suspect the NHC are waiting to see the QS pass this evening before deciding.The overall structure has improved in the last 12 hours so I would say the odds of becoming an Invest by 2 a.m. tonight are somewhere between 60 and 70% IMO


Hey, many already doubted this system becuz of no models support.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
no orange but two yellows
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Oh boy, its been a while since I came in, a few weeks.

Last few weeks the wind shear and currents were wild.

But, just checking the satellite loop...!!!!

Looks like trouble in town.

Just when it looked like the season would spare everyone.

Anyway..here we go again.

Take care.
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507. IKE
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT SUN OCT 4 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A TROPICAL WAVE LOCATED ABOUT 1200 MILES EAST OF THE WINDWARD
ISLANDS IS PRODUCING A LARGE AREA OF DISORGANIZED SHOWERS AND
THUNDERSTORMS. SOME SLOW DEVELOPMENT OF THIS SYSTEM IS POSSIBLE
OVER THE NEXT COUPLE OF DAYS AS IT MOVES WESTWARD AT 15 TO 20 MPH.
THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

SHOWER ACTIVITY HAS INCREASED NEAR THE CENTER OF A NON-TROPICAL
LOW PRESSURE AREA LOCATED ABOUT 225 MILES NORTHEAST OF THE AZORES
ISLANDS. THIS LOW IS MOVING QUICKLY NORTHEASTWARD TOWARD COOLER
WATERS AND DEVELOPMENT INTO SUBTROPICAL OR TROPICAL CYCLONE IS NOT
LIKELY. THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS
SYSTEM BECOMING A SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT
48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BROWN
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Quoting Dakster:


Man, I just GAVE them my last box... BTW, how can an 8pm TWO be late when it is only 7:49pm...
normally out 20 mins before
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...it's probably the remnants of Fred...
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Quoting IKE:
***Paging NHC***

Crayon box sent by FredEX.


ROFL
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting GeoffreyWPB:
Kman...When or if do you think they will label it an invest?


I suspect the NHC are waiting to see the QS pass this evening before deciding.The overall structure has improved in the last 12 hours so I would say the odds of becoming an Invest by 2 a.m. tonight are somewhere between 60 and 70% IMO
Member Since: August 19, 2006 Posts: 0 Comments: 15842
Quoting KEEPEROFTHEGATE:
here it comes get ready wait for it


I've said that before.
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Quoting WeatherStudent:


A, please, thank you.
Boy, you seem to be calmiong down a bit lately. School going good ?
Member Since: October 9, 2008 Posts: 0 Comments: 8393
Quoting GeoffreyWPB:
Kman...When or if do you think they will label it an invest?

after 8z and I think it will be orange
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498. JRRP
Quoting wunderkidcayman:

reminds me of bill what do you guys think

yeah
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Post 448:
I'll go for a 'B' at the 8:00 EST TWO
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i am going to play it safe and say yellow, still :)
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495. IKE
***Paging NHC***

Crayon box sent by FredEX.
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Quoting IKE:
Come on NHC! LOL.


Uh oh! Ike is upcasting...
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here it comes get ready wait for it
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WEATHERSTUDENT - Where you visiting the NHC again? Can you please return their crayons.
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Quoting Dakster:


Why Thank you...

ROFLMAO.
It's just the warm water.
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490. IKE
Come on NHC! LOL.
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Kman...When or if do you think they will label it an invest?
Member Since: September 10, 2007 Posts: 0 Comments: 11282

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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.