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:


Not really interested in the Azores system but think the CATL wave has a better than 50% chance of being classified as a TD within 24 hrs.


The NHC has given the CATL wave a >30% chance of developing and the Azores system a <50% chance- they say they may even initiate advisories "sometime tonight."
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Shear has been faliing quite significantly from 40W all the way to about 75W

1200 miles out will give the CATL wave lots of time to close off a surface low before reaching the Caribbean.
Member Since: August 19, 2006 Posts: 0 Comments: 15725
Quoting Drakoen:


I don't really understand the charts but I take it you are showing Kman that in 84 hrs shear in the Caribbean will not be high at all. Please correct me if I am wrong because it looks like (to my untrained eye) that it will be more conducive.
Member Since: October 9, 2008 Posts: 0 Comments: 8268
Quoting wunderkidcayman:
so when will we have 91L


By the morning... Models should start on 06z, this wave is looking impresive... Who turn out the fan! and opens the caribbean doors. I think is the big antyciclonic over Mexico.
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685. amd
Quoting 1900hurricane:

Yes, now that the EWRC has been completed, Melor should probably strengthen a little. The EWRC is actually probably the reason why Melor weakened from being a Cat 5 Super Typhoon with 145 kt winds to a Cat 5 Super Typhoon with 140 kt winds (not much of a change there, eh? This is probably because the EWRC was so quick and clean).


the eye is as clean now as it has ever been with Melor. However, it looks like convection is eroding slightly in the western eye wall.

Water vapor loop of Melor
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Thanks 1900. Husband and I are stationed in Oki and all the bases are freaking out over this one. I prefer to gather my own information before I freak out! lol, just kidding.
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The AOI needs to develop a surface circulation before getting into the Caribbean. The Caribbean would give it a harder time to form a surface circulation with the slightly above average 850mb winds. The 200mb winds should be significantly reduce and upper level ridging dominates the GOM and Caribbean.
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This is looking more and more like a hit than a near miss. That little edge of land that is going to get hit in this track is the location of a little village named Tokyo.
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Whoops..There it is...

2009 Storms
All Active Year

Atlantic
90L.INVEST

East Pacific

Central Pacific

West Pacific
20W.MELOR
19W.PARMA



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Quoting kmanislander:


You would have to put that up LOL


:)
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679. xcool





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Quoting Drakoen:




You would have to put that up LOL
Member Since: August 19, 2006 Posts: 0 Comments: 15725
Quoting kmanislander:


The current steering flow is to the W but not particularly strong. If it does become classified as a TD the odds of it making it to the NW Caribbean would be low IMO.

I cannot imagine shear remaining low long enough this time of year for a CV system to make it to our neck of the woods but I could be wrong.


I was thinking the same, the models keep shear low through 144 hrs, if this develops and the shear forecast verifies this could be a late season long treker.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting mcswains:
1900 Hurricane- very new to this, but doesn't that mean its getting stonger?

Yes, now that the EWRC has been completed, Melor should probably strengthen a little. The EWRC is actually probably the reason why Melor weakened from being a Cat 5 Super Typhoon with 145 kt winds to a Cat 5 Super Typhoon with 140 kt winds (not much of a change there, eh? This is probably because the EWRC was so quick and clean).
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Quoting kmanislander:


The current steering flow is to the W but not particularly strong. If it does become classified as a TD the odds of it making it to the NW Caribbean would be low IMO.

I cannot imagine shear remaining low long enough this time of year for a CV system to make it to our neck of the woods but I could be wrong.


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Quoting kmanislander:


The current steering flow is to the W but not particularly strong. If it does become classified as a TD the odds of it making it to the NW Caribbean would be low IMO.

I cannot imagine shear remaining low long enough this time of year for a CV system to make it to our neck of the woods but I could be worng.
Hope you're not.
Member Since: October 9, 2008 Posts: 0 Comments: 8268
Quoting GeoffreyWPB:
nrt...why isn't 90l showing up on the Navy pages?


click on one of the Pacific storms and you'll see what happens.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting stormwatcherCI:
It has really started to consolidate this evening. Got a bad feeling on this one since it is so far south. Where do you think it will go if it develops ?


The current steering flow is to the W but not particularly strong. If it does become classified as a TD the odds of it making it to the NW Caribbean would be low IMO.

I cannot imagine shear remaining low long enough this time of year for a CV system to make it to our neck of the woods but I could be wrong.
Member Since: August 19, 2006 Posts: 0 Comments: 15725
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nrt...why isn't 90l showing up on the Navy pages?
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1900 Hurricane- very new to this, but doesn't that mean its getting stonger?
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Navy is using GOES-12 and 90L is located far from the focal point so the resolution is poor.

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


Not really interested in the Azores system but think the CATL wave has a better than 50% chance of being classified as a TD within 24 hrs.
It has really started to consolidate this evening. Got a bad feeling on this one since it is so far south. Where do you think it will go if it develops ?
Member Since: October 9, 2008 Posts: 0 Comments: 8268
Member Since: June 28, 2006 Posts: 24 Comments: 8201
I don't think that many people have realized this, but Melor actually went through an Eyewall Replacement Cycle overnight.


This is from earlier today (overnight where Melor is). Note how the EWRC isn't particularly overt until after looking the microwave imagery.


This one is more recent, just as Melor is finishing the EWRC.
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663. xcool



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Quoting stormwatcherCI:
Welcome back. What say you on our two systems ?


Not really interested in the Azores system but think the CATL wave has a better than 50% chance of being classified as a TD within 24 hrs.
Member Since: August 19, 2006 Posts: 0 Comments: 15725
90L



CATL Wave

Member Since: July 24, 2005 Posts: 407 Comments: 19076
05/0000 UTC 40.1N 21.2W T2.0/2.0 90L -- Atlantic
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I am originally from Alabama and when we get storms, the east side of the storm is usually worse. Is that the same deal with the storms now that I live in Okinawa? I have read that typhoons and hurricanes are the same thing- just different names.
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I'm out!

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM
SPECIAL TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
905 PM EDT SUN OCT 4 2009

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

1. SPECIAL OUTLOOK ISSUED TO UPDATE DISCUSSION OF LOW NORTHEAST OF THE
AZORES

2. SHOWER ACTIVITY ASSOCIATED WITH THE AREA OF LOW PRESSURE LOCATED
ABOUT 300 MILES EAST-NORTHEAST OF THE AZORES ISLANDS HAS CONTINUED
TO BECOME BETTER ORGANIZED AND THE SYSTEM APPEARS TO BE ACQUIRING
TROPICAL CHARACTERISTICS. IF THIS TREND CONTINUES OVER THE NEXT
HOUR OR TWO...ADVISORIES ON A TROPICAL STORM WILL BE INITIATED
LATER THIS EVENING. THERE IS A HIGH CHANCE...GREATER THAN 50
PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT FEW HOURS.

3. 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.

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

Member Since: August 9, 2009 Posts: 10 Comments: 4898
Well, even with it's midget size overall - if it has a well developed eye and is acquiring tropical charactistics, should it not be a hurricane?

How many tropical storms do you see with such a good looking eye?
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Quoting kmanislander:
,
Welcome back. What say you on our two systems ?
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Quoting stormwatcherCI:
CATL looks like it is pulling itself together now too. Looks like maybe a late season.


As for the CATL wave, yea it has really consolidated compared to this morning. If this continues yea I'm still expecting 91L probably on Monday.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Good evening,

24 hours ago, we were bashing the NHC for not even considering Invest 90-L; 24-hours later, now they consider it (looks like it has a small eye)!

This is Hurricane Vince 2005 all over again! All of the sudden, the NHC consider it Vince seemingly out of nowhere. Maybe, this will become Hurricane Grace!
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Post 640:
NHC should have made 90L colored red a couple days ago.
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,
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651. beell
Ok, ok!
IF THIS TREND CONTINUES OVER THE NEXT
HOUR OR TWO...ADVISORIES ON A TROPICAL STORM WILL BE INITIATED
LATER THIS EVENING.


ok, I gotta say something in defense of my argument!
APPEARS TO BE ACQUIRING TROPICAL CHARACTERISTICS

Meaning it did not have them up to this point.


Gosh, how 'bout that Cent ATL Wave...
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wow
Member Since: June 28, 2006 Posts: 24 Comments: 8201
Quoting Chicklit:
It's hot and muggy in ecentralfla again. drats!
night all.


I'm here in Nashville, TN. May I borrow some of that warm air please. It's 54F and raining, YUCK!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
648. Skyepony (Mod)
weather456~ quikscat was pretty sloppy with 2 LLC in the area, the one I'm thinking it is was pretty elongated.. didn't seem to have it together at the surface. Does look better now by satellite than a few hours ago.
Member Since: August 10, 2005 Posts: 161 Comments: 37346
Quoting Weather456:


*big grins*
Be proud of yourself and what you do. You are very intelligent for one so young and I certainly listen and learn from you as I am sure many more do.
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Quoting mcswains:
Posting from Okinawa Japan and watching Melor. Everyone think this thing is actually going to turn before it hits us here?

It's predicted to just scrape the cost. Let's hope it stays that way, or better yet, it goes farther out to sea.


Member Since: August 9, 2009 Posts: 10 Comments: 4898
456-

nice call! (:
Member Since: June 28, 2006 Posts: 24 Comments: 8201
It's hot and muggy in ecentralfla again. drats!
night all.
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Dang! 456.. your the bomb.
Tropical Storm Grace shortly!
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Quoting Weather456:
YES! I'm not crazy!
CATL looks like it is pulling itself together now too. Looks like maybe a late season.
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Quoting stormwatcherCI:
Far from it. That's why you need to forget about what some rabblerousers are saying and go with what you know.


*big grins*
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639. xcool
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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.