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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Quoting WeatherStudent:
Not cool, EX. THANK GOD that you have absolutely no saying in regards to who cant and who cannot blog on this blog. I praise to the Lord one million times for that being the actual case. Anyways, back to the 96L disussion going on here tonight. Kman, so your seeing an early demise to this year's Cape Verde Season, then? Also, what are your initial thoughts on what might await the Carib. during Oct. since that's typically the month that both you and I tend to be in the greatest threat for TC strikes, sir?


Actually I think the entire season may end early. Shear has been high from June 1st and there are no signs that it will abate any time soon. I am concerned that if anything were to form in the Caribbean in October or November it could become quite intense very quickly. We will have to wait and see but shear looks to be king this year.
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1143. JLPR


more models running on 96L
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Yeah, I don't even know why we are even blogging about 96L. Let's move on to 97L, 98L, 99L back to 90L and so on.
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Quoting Leafgreen:
Q: The last few invests to come off the African coast have had "spin". Why do these waves have spin? Do they have spin over land or do they immediately acquire it when over water? If they have spin over land, why don't large storms over other continents, such as supercells over CONUS or Colombia, have spin?


Essentially the unique characteristics associated with conditions that produce these waves, including topography, causes them to "spin" as they become areas of low pressure exiting the West African coast as Easterly waves.

See this extract from an article taken from the Nasa Observatory site.

"The last and most common mechanism that triggers the development of a cyclone is the African easterly wave, an area of disturbed weather that travels from east to west across the tropical Atlantic. Essentially, an easterly wave forms because of a “kink” in the jet of air that flows west out of Africa. The jet is created by the strong temperature difference between the Sahara Desert and the Gulf of Guinea. The warm air over the Sahara rises and, several kilometers above the surface, turns southward toward the cooler air over the Gulf. The rotation of the Earth turns this air current westward to form the African Easterly Jet, which then continues out over the Atlantic Ocean. Occasionally, a “kink” will develop in the jet and move from east to west, hence the name easterly wave. Converging winds on the east side of the easterly wave trigger the development of thunderstorms, and some of these large thunderstorm systems go on to become hurricanes. Most Atlantic hurricanes can be traced to easterly waves that form over Western Africa."

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Quoting TampaSpin:


Evening all NOTHING can develop in the GOM with the current conditions.....and they are forecast to get even worse.


Until later next week.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting hercj:
Are the models picking up on 96L yet?


They've been for days, before 96L even left the coast they made it into a Hurricane.
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Not cool, EX. THANK GOD that you have absolutely no saying in regards to who cant and who cannot blog on this blog. I praise to the Lord one million times for that being the actual case. Anyways, back to the 96L disussion going on here tonight. Kman, so your seeing an early demise to this year's Cape Verde Season, then? Also, what are your initial thoughts on what might await the Carib. during Oct. since that's typically the month that both you and I tend to be in the greatest threat for TC strikes, sir?
1137. hercj
The majority of the models keep 96L south of 15N at 36 hours. Interesting.
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1136. KEEPEROFTHEGATE (Mod)


AOI/XX/XX
MARK
22.6N/93.6W
Member Since: July 15, 2006 Posts: 175 Comments: 54847
Quoting HurricaneKyle:


Plus Bremuda, the Cape Verdes and Canada. But WeatherStudent is to much of a troll to care about any other effected landmass. He really, honestly needs to be banned.



yup
Member Since: May 21, 2006 Posts: 5091 Comments: 115356
Quoting HurricaneKyle:


Plus Bremuda, the Cape Verdes and Canada. But WeatherStudent is to much of a troll to care about any other effected landmass. He really, honestly needs to be banned.


yeah, he definitely needs banned, im sick of him, i tried to help him, but he gets ridiculous
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Quoting hercj:
Are the models picking up on 96L yet?

Dr. Masters wrote about 96L in his blog above: "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."
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Quoting laflastormtracker:
Amazing how quickly only a few hours at most it took this AOI in the Gulf to change from linear to a circular, more tropical looking system. Back to blob watching.


Evening all NOTHING can develop in the GOM with the current conditions.....and they are forecast to get even worse.
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96L may be going out too sea but in its path there are fishing vessels so we sould not call this a fish storm
Member Since: May 21, 2006 Posts: 5091 Comments: 115356
Quoting Tazmanian:
he right there are lot of fishing vessels in the path of this storm


Plus Bremuda, the Cape Verdes and Canada. But WeatherStudent is to much of a troll to care about any other effected landmass. He really, honestly needs to be banned.
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1129. hercj
Thanks Keeper.
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G'evening, Kman.
he right there are lot of fishing vessels in the path of this storm
Member Since: May 21, 2006 Posts: 5091 Comments: 115356
1125. KEEPEROFTHEGATE (Mod)
736

WHXX01 KWBC 070044

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

0044 UTC MON SEP 7 2009



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



DISTURBANCE INVEST (AL962009) 20090907 0000 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

090907 0000 090907 1200 090908 0000 090908 1200



LAT LON LAT LON LAT LON LAT LON

BAMS 12.6N 19.6W 13.0N 22.9W 13.2N 26.2W 13.1N 29.9W

BAMD 12.6N 19.6W 12.9N 22.4W 13.3N 25.1W 14.0N 27.7W

BAMM 12.6N 19.6W 12.8N 22.5W 13.2N 25.3W 13.7N 28.3W

LBAR 12.6N 19.6W 12.7N 22.9W 13.1N 26.5W 13.6N 29.9W

SHIP 25KTS 33KTS 41KTS 54KTS

DSHP 25KTS 33KTS 41KTS 54KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

090909 0000 090910 0000 090911 0000 090912 0000



LAT LON LAT LON LAT LON LAT LON

BAMS 13.0N 33.7W 12.6N 38.1W 13.0N 37.0W 14.0N 32.1W

BAMD 14.7N 30.2W 17.3N 34.4W 20.5N 36.2W 23.3N 36.5W

BAMM 14.2N 31.2W 15.7N 36.0W 17.4N 37.3W 19.2N 35.6W

LBAR 14.4N 33.0W 16.5N 37.4W 19.9N 38.1W 24.4N 38.2W

SHIP 65KTS 78KTS 78KTS 73KTS

DSHP 65KTS 78KTS 78KTS 73KTS



...INITIAL CONDITIONS...

LATCUR = 12.6N LONCUR = 19.6W DIRCUR = 270DEG SPDCUR = 18KT

LATM12 = 12.5N LONM12 = 16.0W DIRM12 = 270DEG SPDM12 = 20KT

LATM24 = 12.5N LONM24 = 10.4W

WNDCUR = 25KT RMAXWD = 60NM WNDM12 = 25KT

CENPRS = 1007MB OUTPRS = 1011MB OUTRAD = 225NM SDEPTH = M

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN
Member Since: July 15, 2006 Posts: 175 Comments: 54847
Quoting Relix:
I don't like those south model tracks =P



There is no way this baby makes it too far west.
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Quoting Stormchaser2007:


Apparently the hundreds of fishing vessels and other marine craft dont count.


WeatherStudent is just clueless, he said the same thing about Bill (and I bet he still does) that it was just a storm for the fishes. Apparently it has the effect the US for it to be significant, which is completely untrue. My advice is ignore him, let the Admins take him one of these days (because really he should have been banned after his little outburst during Bill)
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1121. hercj
Are the models picking up on 96L yet?
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1120. Relix
I don't like those south model tracks =P
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1118. JLPR
Quoting extreme236:


The structure is well organized but the center isn't directly under the convection yet. Still organizing though.


ha! said the same thing =P
then again maybe the center will jump and locate itself under the convection
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Q: The last few invests to come off the African coast have had "spin". Why do these waves have spin? Do they have spin over land or do they immediately acquire it when over water? If they have spin over land, why don't large storms over other continents, such as supercells over CONUS or Colombia, have spin?
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Quoting 1900hurricane:

Just curious: why so low? Is it that it is a relatively new invest, or because it isn't too organized yet, or some other reason?


Probably because the low is not well organised.

Very linear. See my post 1109
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Quoting extreme236:


The structure is well organized but the center isn't directly under the convection yet. Still organizing though.

Cool, thanks!
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Quoting WeatherStudent:


Are you either an oceanographer or marine scientist? Then why do you care, Chaser? As Adrian said on here earlier on today, this cane season thus far has been absolutely horrendous for the die-heart hurricane chasers.


well let's see, the people on the ships out there care an awful lot WS
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Quoting WeatherStudent:


Are you either an oceanographer or marine scientist? Then why do you care, Chaser? As Adrian said on here earlier on today, this cane season thus far has been absolutely horrendous for the die-heart hurricane chasers.


Then why are you on the blog? Trolling around isn't cool. And the people who are on fishing vessels care.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1112. JLPR
Quoting 1900hurricane:

Just curious: why so low? Is it that it is a relatively new invest, or because it isn't too organized yet, or some other reason?


probably because it places the center to the east of the convection
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting 1900hurricane:

Just curious: why so low? Is it that it is a relatively new invest, or because it isn't too organized yet, or some other reason?


The structure is well organized but the center isn't directly under the convection yet. Still organizing though.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
hi guys I see that we have 96L ready to become Fred the dreaded F name well I would not be surprised if it becomes a caribbean hurricane then hit cuba then south of east Fl
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Good evening everyone

I just took a look at the quikscat pass for 96L and what I saw was a convergence line of low pressure oriented NW to SE from 14 to 11 N.

Where it goes will depend on several factors, including how far North the low finally consolidates and secondly how strong it becomes and how soon.

Given what the far Eastern Atl looks like already I am sceptical that anything will makes its way across from Africa the rest of the season. Some will say it is too soon to be calling for a shut down of the CV season but in the absence of a sudden and significant shift in the conditions that have prevailed to date that is my view.

Quikscat
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Amazing how quickly only a few hours at most it took this AOI in the Gulf to change from linear to a circular, more tropical looking system. Back to blob watching.
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Quoting Stormchaser2007:


Apparently the hundreds of fishing vessels and other marine craft dont count.


Are you either an oceanographer or marine scientist? Then why do you care, Chaser? As Adrian said on here earlier on today, this cane season thus far has been absolutely horrendous for the die-heart hurricane chasers.
Quoting Stormchaser2007:
Hot off the printer.

06/2345 UTC 12.9N 19.9W T1.0/1.0 96L

Just curious: why so low? Is it that it is a relatively new invest, or because it isn't too organized yet, or some other reason?
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Ill be back at around 2am.
Member Since: June 9, 2007 Posts: 4 Comments: 15946
Quoting Tropix3:
Fred's wife Wilma was a pain in the arse so I really hope Fred is friendlier to S. FL.


Hope he doesn't come looking for her
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Quoting BurnedAfterPosting:


96L is clearly moving W-WNW, not sure what you are looking at


Maybe he's have some visual issues.LOL
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The TWD has updated, just not the link info. They forgot to change the date of issuance, but the time stamp indicates the 00Z time.

000
AXNT20 KNHC 070003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN SEP 06 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.


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96L looking very good at this hour and is likely to become a TD tomorrow, IMO.
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AL, 96, 2009090700, , BEST, 0, 126N, 196W, 25, 1007,
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting Tazmanian:
96L looks too be moveing N or NNE but the nhc says its moveing W-WNW so hmmm


96L is clearly moving W-WNW, not sure what you are looking at
1097. hydrus
Quoting Stormchaser2007:


Apparently the hundreds of fishing vessels and other marine craft dont count.
If they have any brains they will get out of the way if a storm heads toward them.
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Quoting Tazmanian:
96L looks too be moveing N or NNE but the nhc says its moveing W-WNW so hmmm


Where do you see that?

That would take it back to Africa.

Its moving WNW. No doubt about it.
Member Since: June 9, 2007 Posts: 4 Comments: 15946
96L looks too be moveing N or NNE but the nhc says its moveing W-WNW so hmmm
Member Since: May 21, 2006 Posts: 5091 Comments: 115356
1094. hydrus
Quoting antonio28:


LOL Fred will be a Major fishy!!
The fish can have him.
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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.