The tropics are quiet

By: Dr. Jeff Masters , 1:11 PM GMT on September 06, 2009

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Considering that this is historically the peak week of the Atlantic hurricane season, the tropics are quiet. There is an area of disturbed weather in the middle Atlantic (95L) that NHC has been mentioning in their Tropical Weather Outlook the past day, but this disturbance is entering a region of high wind shear and is not a threat to develop.

A strong tropical wave with plenty of rotation is emerging off the coast of Africa this morning, and this wave is a good candidate to show some development this week as it heads west-northwest over the Atlantic. The wave is under about 15 knots of wind shear, and is being developed by several models, including the GFS and ECMWF. However, the models show that this new wave will be pulled northwestward by a strong trough of low pressure this week, and it appears unlikely that the wave will make the long crossing of the Atlantic necessary to threaten any land areas. Another wave with plenty of spin will emerge from the coast of Africa two days from now, and will also have a chance to develop.


Figure 1. Morning satellite image of 95L and a new tropical wave with potential to develop, emerging from the coast of Africa.

An area of concentrated thunderstorms has developed off the North Carolina coast in association with the remains of an old cold front. This system is under about 20 - 30 knots of shear, and is not tropical. However, it will bring heavy rain just offshore of North Carolina's Outer Banks today as it slides north-northeastward along the coast.

I'll have an update Monday.

Jeff Masters

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1094. hydrus
Quoting antonio28:


LOL Fred will be a Major fishy!!
The fish can have him.
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Hot off the printer.

06/2345 UTC 12.9N 19.9W T1.0/1.0 96L
Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting WeatherStudent:


No worries there, unless your a fish, of course.


LOL Fred will be a Major fishy!!
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Quoting Patrap:




Lotsa Rain at Least for Us seems,..as to Development,Ill refer to the NHC,tonight.




Yeah, we got a lot last night and more just came through...I'll go check it out.
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Quoting WeatherStudent:


No worries there, unless your a fish, of course.


Apparently the hundreds of fishing vessels and other marine craft dont count.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
1089. Patrap
GOM 84 Hour Wave Forecast Model (using MIKE21)
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Seems that NHC is waiting the Dpass over the GOM to issue a TWD. IMO, something is starting to spin right there, not Good.
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Member Since: June 9, 2007 Posts: 4 Comments: 15776
1085. Patrap
Quoting hurricanehanna:

Hey Pat - just popping in for a minute....something interesting starting to happen in the GOM?




Lotsa Rain at Least for Us seems,..as to Development,Ill refer to the NHC,tonight.



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1084. Patrap
ADCP Directional Spectrum
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Quoting Patrap:
WAVCIS by LSU

csi - 16
Location:Chevron MP41M platform, Coordinates:89 02.128',29 24.07'

Hey Pat - just popping in for a minute....something interesting starting to happen in the GOM? I just ran the CMC and me no likey!
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interesting show about Tropical Storm Erin on TWC
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Quoting Patrap:


That's looks very interesting....
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1078. Patrap
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1077. Patrap
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Quoting sebastianflorida:
Funny you should talk about TD when you keep saying the season is over when there is nothing happening at the moment. I said the season is over, however I don't cry the storm is comming every other day. Maybe California fires would better be your cup of tea as a hobby you could follow them on another blog.


c'mon, lay off please
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Ill have a speacial update on 96L by tomorrow.

Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting BahaHurican:
Is it me, or did the TWD not update yet? They're not usually THIS late.... wonder what's up/


Yeap I think GOM is probably the responsible.
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Quoting Tazmanian:
96L looks like a TD has i talk too you right now
Funny you should talk about TD when you keep saying the season is over when there is nothing happening at the moment. I said the season is over, however I don't cry the storm is comming every other day. Maybe California fires would better be your cup of tea as a hobby you could follow them on another blog.
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Is it me, or did the TWD not update yet? They're not usually THIS late.... wonder what's up/
Member Since: October 25, 2005 Posts: 19 Comments: 21391
1071. Tropix3
Thank You, that was exactly what I wanted to hear!
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Quoting Tropix3:
....
Wow. The relevant body part, correctly spelled for a change! Don't see that often... lol

But a hearty cheers to strong storms staying away from land....
Member Since: October 25, 2005 Posts: 19 Comments: 21391
Quoting nishinigami:
Could someone explain if the CMC is showing what futuremet was talking about earlier in the GOM?


edit, here is the link, sorry about that...

Link


18z NAM 84 hrs. is looking to support something in the gulf...

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Quoting Tropix3:
Fred's wife Wilma was a pain in the arse so I really hope Fred is friendlier to S. FL.


Fred is more than likely headed out to sea. Trough is just too strong.
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1067. JLPR
yep its looking too interesting
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96L looks like a TD has i talk too you right now
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1065. Tropix3
Fred's wife Wilma was a pain in the arse so I really hope Fred is friendlier to S. FL.
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1064. JLPR
Quoting jurakantaino:
yes i been following this low ,very persistent , i wonder what would happen if shear relaxes a bit .


not much the circulation is gone now

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Quoting HurricaneKyle:
Any recent T# on 96L?


Nope. Should have one eventually.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
Thanks Ike, the CMC has that low going over my house :O
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Any recent T# on 96L?
Member Since: August 10, 2009 Posts: 3 Comments: 672
1060. JLPR
Quoting BurnedAfterPosting:


looks like that pass is from this morning actually, timestamp says it is; also looks like the circulation has deteriorated since then; lates QS shows that


yep wind shear is getting to it
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Quoting BGMom:


I am just Northwest of Atlanta and every year we PRAY for a decent snow that will last more than 5 minutes.

U have mail! :)
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1058. IKE
Quoting nishinigami:
Could someone explain if the CMC is showing what futuremet was talking about earlier in the GOM?


edit, here is the link, sorry about that...

Link


It's probably connected. Latest GFS keeps a low inland. Models will probably zero in on what actually will happen within the next couple of days.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
May be surprised as to what we find tomorrow.

Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting hydrus:
I wonder the last time that happend?

1953
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Quoting hydrus:
I wonder the last time that happend?


Blizzard of '93
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Could someone explain if the CMC is showing what futuremet was talking about earlier in the GOM?


edit, here is the link, sorry about that...

Link
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Quoting JLPR:
interesting circulation with the Catl wave lol



no west winds! yet it looks so round lol


looks like that pass is from this morning actually, timestamp says it is; also looks like the circulation has deteriorated since then; lates QS shows that
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Quoting JLPR:
interesting circulation with the Catl wave lol



no west winds! yet it looks so round lol
yes i been following this low ,very persistent , i wonder what would happen if shear relaxes a bit .
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1051. hydrus
Quoting BGMom:


I am just Northwest of Atlanta and every year we PRAY for a decent snow that will last more than 5 minutes.
I wonder the last time that happend?
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Quoting IKE:


They took off the yellow circle off of the Carolina's. So much for Bastardi's thoughts on that blob.


LOL

Yeah. I never thought much of it anyways.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting futuremet:


Thanks

wow...it looks like 12Z ECMWF is expecting a similar case scenario...I did not realize that.


Yeah, I saw that. Either a welcoming cold front or a big mess for somebody.
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1048. JLPR
interesting circulation with the Catl wave lol



no west winds! yet it looks so round lol
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Quoting futuremet:
Bonsoir everyone


It looks like we will have to monitor the GOM closely during the latter part of next week, as a potent longwave trough traverses across the Midwest. The trough is expected to split and slightly troughing in southward, thus kindling upper level anticyclogenesis across the area. The anticyclone will form due to positive vorticity advection at the eastern axis of the longwave trough. Like fluids, air has a tendency to rotate at its own axis, and typically flows from areas of higher speed to lower speed. Therefore some the fast moving air moving from the southwest will start curving toward the south. This is why upper level anticyclones typically form proportionally by the area of highest winds along the trough axis. The formation of the upper ridge will help decrease wind shear values over the GOM, which will great tropical cyclone formation. Since upper level ridges do not have a pronounced effect on steering current, the longwave trough to the north will likely steer anything that forms NE. Now, I am not saying anything will form, but there is a possibility something will. This may very well be the last chance for anything to form in the GOM, before it closes down in October due to shear. The anomalously warm SSTs in the GOM will propagate southward to the Caribbean as we near the month of October. In addition, the MJO will help increase values across the Caribbean. Troughs nosing in southward will provide additional energy for tropical cyclone formation; like in hurricane Wilma of 2005. Hopefully this weak el nino will induce adequate shear to stop anything major from forming; or hopefully the troughs are so strong that the cause these storms to move ENE , like we saw in latter part of 2008 with Omar and Paloma.

Strong Upper level ridge

Image and video hosting by TinyPic

Low Shear

<>img src="Image and video hosting by TinyPic" alt="" />


thanks!
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Red circle in the EPac, though:

TTAA00 KNHC DDHHMM
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
500 PM PDT SUN SEP 6 2009

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

1. SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH AN AREA OF LOW
PRESSURE LOCATED ABOUT 1100 MILES WEST-SOUTHWEST OF THE SOUTHERN
TIP OF BAJA CALIFORNIA HAS DECREASED DURING THE DAY. HOWEVER...
CONDITIONS ARE STILL FAVORABLE FOR FURTHER DEVELOPMENT...AND THIS
SYSTEM COULD BECOME A TROPICAL DEPRESSION TONIGHT OR TOMORROW AS IT
MOVES SLOWLY WEST-NORTHWESTWARD AT AROUND 5 MPH. THERE IS A HIGH
CHANCE...GREATER THAN 50 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.

$$
FORECASTER BERG
NNNN
Member Since: October 25, 2005 Posts: 19 Comments: 21391
1044. IKE
Quoting Stormchaser2007:
Nothing has changed in the TWO.

No update needed.


They took off the yellow circle off of the Carolina's. So much for Bastardi's thoughts on that blob.
Member Since: June 9, 2005 Posts: 23 Comments: 37858

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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.