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Atlantic Tropical Action 2012 - Part I


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People scoff at the NAM and Canadian as tropical guidance, but I specifically remember they were the first to pick up on Edouard, and neither is pocking up on whatever is in the Gulf. NAM is picking up something toward the end of the run that doesn't close a surface low coming from the Southeast, but unrelated to this.

Not a model hugger, but I'd like to see 1 model onboard.

The convection blow up approaching the FL straits this morning. It's associated with what appears to be a TW currently in the area. There might be some organization as it moves WNW to NW towards the N or NE GoM, but upper level conditions remain marginal

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The convection blow up approaching the FL straits this morning. It's associated with what appears to be a TW currently in the area. There might be some organization as it moves WNW to NW towards the N or NE GoM, but upper level conditions remain marginal

It has a lemon.

ABNT20 KNHC 221439

TWOAT

SPECIAL TROPICAL WEATHER OUTLOOK

NWS NATIONAL HURRICANE CENTER MIAMI FL

1040 AM EDT SUN JUL 22 2012

FOR THE NORTH ATLANTIC...CARIBBEA N SEA AND THE GULF OF MEXICO...

A VIGOROUS TROPICAL WAVE LOCATED OVER THE NORTHWESTERN BAHAMAS AND

THE FLORIDA STRAITS IS PRODUCING NUMEROUS SHOWERS AND A FEW STRONG

THUNDERSTORMS. A WIND GUST TO 53 MPH WAS RECENTLY REPORTED AT FOWEY

ROCKS FLORIDA...AND DOPPLER WEATHER DATA INDICATE STRONGER

THUNDERSTORMS ARE LOCATED OFFSHORE THE SOUTHEAST FLORIDA COAST.

SURFACE PRESSURES ARE HIGH AND UPPER-LEVEL WINDS ARE ONLY

MARGINALLY CONDUCIVE FOR DEVELOPMENT...SO ANY ADDITIONAL

ORGANIZATION OF THIS SYSTEM SHOULD BE SLOW TO OCCUR. REGARDLESS OF

DEVELOPMENT...THIS DISTURBANCE WILL BRING PERIODS OF STRONG GUSTY

WINDS AND LOCALLY HEAVY RAINFALL TO PORTIONS OF THE NORTHWESTERN

BAHAMAS...CENTRAL AND SOUTHERN FLORIDA...AND THE FLORIDA KEYS OVER

THE NEXT DAY OR SO. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...OF

BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES

NORTHWESTWARD AT AROUND 15 MPH.

ELSEWHERE...TROPICA L CYCLONE FORMATION IS NOT EXPECTED DURING THE

NEXT 48 HOURS.

$$

FORECASTER STEWART

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It has a lemon.

ABNT20 KNHC 221439

TWOAT

SPECIAL TROPICAL WEATHER OUTLOOK

NWS NATIONAL HURRICANE CENTER MIAMI FL

1040 AM EDT SUN JUL 22 2012

FOR THE NORTH ATLANTIC...CARIBBEA N SEA AND THE GULF OF MEXICO...

A VIGOROUS TROPICAL WAVE LOCATED OVER THE NORTHWESTERN BAHAMAS AND

THE FLORIDA STRAITS IS PRODUCING NUMEROUS SHOWERS AND A FEW STRONG

THUNDERSTORMS. A WIND GUST TO 53 MPH WAS RECENTLY REPORTED AT FOWEY

ROCKS FLORIDA...AND DOPPLER WEATHER DATA INDICATE STRONGER

THUNDERSTORMS ARE LOCATED OFFSHORE THE SOUTHEAST FLORIDA COAST.

SURFACE PRESSURES ARE HIGH AND UPPER-LEVEL WINDS ARE ONLY

MARGINALLY CONDUCIVE FOR DEVELOPMENT...SO ANY ADDITIONAL

ORGANIZATION OF THIS SYSTEM SHOULD BE SLOW TO OCCUR. REGARDLESS OF

DEVELOPMENT...THIS DISTURBANCE WILL BRING PERIODS OF STRONG GUSTY

WINDS AND LOCALLY HEAVY RAINFALL TO PORTIONS OF THE NORTHWESTERN

BAHAMAS...CENTRAL AND SOUTHERN FLORIDA...AND THE FLORIDA KEYS OVER

THE NEXT DAY OR SO. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...OF

BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES

NORTHWESTWARD AT AROUND 15 MPH.

ELSEWHERE...TROPICA L CYCLONE FORMATION IS NOT EXPECTED DURING THE

NEXT 48 HOURS.

$$

FORECASTER STEWART

Latest CIMSS analyses have well-defined upper-level divergence, but an elongated, poorly-defined vorticity maximum. Kinda what you'd expect from a tropical MCS with low chances of development.

Latest GFS and ECMWF appear to track the majority of the parent vorticity into the FL panhandle, which would certainly bring about an end to this wave. If the wave stays further south than guidance suggests, then we might at least have a chance at development. Moisture is not an issue: PWs are > 3 sigma above climo per 6Z GFS ensembles. Inhospitable shear tends to be confined to the W Gulf at the moment.

So I wouldn't completely rule out a chance of development, but this system has a ways to go in terms of structure and building the vortex.

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Very vigorous wave about to pass through the Florida straights.

Could become an invest if a low can consolidate at the mid-levels in the next 48 hours. Looks pretty interesting now.

isavfls.gif

In my amateur opinion, 10 to 20% sounds right. Not much low level vorticity per CIMMS analysis, shear gets lighter further West, but low and low-mid steering suggests it stays close to Florida as it tracks Northwest.

Side note, while seeing where GFS takes the 700 mb moisture with this and whether it closes a low, I note through 6 days GFS is tracking a decent looking wave into the meat of the MDR. 250 mb winds look not particularly hostile near the wave at that time.

post-138-0-55463500-1342974207_thumb.gif

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Latest CIMSS analyses have well-defined upper-level divergence, but an elongated, poorly-defined vorticity maximum. Kinda what you'd expect from a tropical MCS with low chances of development.

Latest GFS and ECMWF appear to track the majority of the parent vorticity into the FL panhandle, which would certainly bring about an end to this wave. If the wave stays further south than guidance suggests, then we might at least have a chance at development. Moisture is not an issue: PWs are > 3 sigma above climo per 6Z GFS ensembles. Inhospitable shear tends to be confined to the W Gulf at the moment.

So I wouldn't completely rule out a chance of development, but this system has a ways to go in terms of structure and building the vortex.

Convection is not as strong as before, and the area with maximum vorticity has little cloud coverage, but the previous convection blowup helped define the area of vorticity, with a rather well defined maxima around 700mb, as shown by CIMSS analyses, 850mb is still elongated but better defined. It's currently underneath a small anticyclone, but it's moving toward an area with low shear. Mixed feelings about it. Strong convection activity next few hours could mean further organization and better chances to squeeze a TS.

post-29-0-32247300-1343003425_thumb.gif

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12z GFS takes this wave and another impressive wave after it and attempts to develop both. Interesting change of pace from the previous runs.

Should hopefully give at least an invest or pouch to track.

Looking at the GFS 5 day forecast for system number 1, the pouch manages to take the path of least resistance, avoiding the worst westerly shear to the north and easterly shear to the south. Dry air entrainment could be an issue on the north side of the system, although the pouch appears to be somewhat moist. Velocity potential does not look particularly favorable per Mike Ventrice's page.

My guess right now is completely fizzled out within 48 hrs at worst, or something similar to Gaston 2010 at best.

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Looking at the GFS 5 day forecast for system number 1, the pouch manages to take the path of least resistance, avoiding the worst westerly shear to the north and easterly shear to the south. Dry air entrainment could be an issue on the north side of the system, although the pouch appears to be somewhat moist. Velocity potential does not look particularly favorable per Mike Ventrice's page.

My guess right now is completely fizzled out within 48 hrs at worst, or something similar to Gaston 2010 at best.

That's a very narrow range :D

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That's a very narrow range :D

Even though it's starting to pick up model support, it's just coming off Africa now, so it can easily go "poof". On the other hand, Gaston was a very crappy, short-lived system, so that upper-bound is still pretty low.

So even though you're being facetious, it's not like I said it could either dissipate in 48 hrs or be a cat 5 Caribbean cruiser. ;)

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12z ECMWF is pretty interesting as well.

Takes the current wave over W-Africa and brings it across the whole CATL with minimal development. Then proceeds to develop it just north of the Islands at the end of the run.

FWIW...nice trof over the coast.

12zeurotropical850mbVortSLP240.gif

Sad news there, for East Coast action fans, is the NAEFS and ensemble means keep a trough near the East Coast through two weeks, and its probably early for any negative tilt trough action. Glass 7/65th full, some of the individual GFS ensemble members out around Day 10 are flatter and further West with the trough, which holds out at least slim hope for either something sneaking through to Florida or coming close enough to Cape Cod for a wave watching party. GFS ensemble means, however, if it develops at all, its a fish.

But a lot can change in 10 days.

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12z ECMWF is pretty interesting as well.

Takes the current wave over W-Africa and brings it across the whole CATL with minimal development. Then proceeds to develop it just north of the Islands at the end of the run.

FWIW...nice trof over the coast.

12zeurotropical850mbVortSLP240.gif

Yep..its been the norm the last couple of years. :(

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Even though it's starting to pick up model support, it's just coming off Africa now, so it can easily go "poof". On the other hand, Gaston was a very crappy, short-lived system, so that upper-bound is still pretty low.

So even though you're being facetious, it's not like I said it could either dissipate in 48 hrs or be a cat 5 Caribbean cruiser. ;)

Actually I was mocking Gaston...fizzling or being one of the crappiest/short lived TS in the last few years is indeed a very narrow range.

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Generalities, not specifics, as we get into August, some modelling, (thinking GFS ensembles) starting to see TCs. Nothing particular to hang a hat on, but the trend is positive. Last week run after run of the GFS ensembles, not a single perturbation would spit out even a closed 1008 mb low.

Not to mention two consecutive runs of Euro hinting at a Fish called Ernesto.

post-138-0-55327500-1343129637_thumb.gif

post-138-0-28423800-1343129650_thumb.jpg

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WRT the 00z ECMWF, this wave is easily trackable across the whole MDR for the next week or so until it develops rather far north of the islands (and ultimately heads for the fishes as a small system)

Wish I could post the AccuWx version, because the amount of 850 vort is actually kinda impressive as it makes it's journey over the next few days.

Might see some kind of shading of this one over the next few days.

EDIT: The 00z GFS has a trackable system in the long range FWIW

eatl_ir_loop.gif

Easily identifiable

vwind650_east.png

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^^

A NON-TROPICAL LOW PRESSURE SYSTEM LOCATED ABOUT 575 MILES

EAST-NORTHEAST OF BERMUDA IS PRODUCING A SMALL AREA OF SHOWERS AND

THUNDERSTORMS. ALTHOUGH THIS DISTURBANCE IS PRIMARILY ASSOCIATED

WITH A FRONTAL SYSTEM...IT COULD STILL PRODUCE GALE-FORCE WINDS

BEFORE IT REACHES MUCH COOLER WATERS ON WEDNESDAY. THIS SYSTEM HAS

A LOW CHANCE...10 PERCENT...OF BECOMING A SUBTROPICAL OR TROPICAL

CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES NORTHEASTWARD AT ABOUT

15 MPH.

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^^

A NON-TROPICAL LOW PRESSURE SYSTEM LOCATED ABOUT 575 MILES

EAST-NORTHEAST OF BERMUDA IS PRODUCING A SMALL AREA OF SHOWERS AND

THUNDERSTORMS. ALTHOUGH THIS DISTURBANCE IS PRIMARILY ASSOCIATED

WITH A FRONTAL SYSTEM...IT COULD STILL PRODUCE GALE-FORCE WINDS

BEFORE IT REACHES MUCH COOLER WATERS ON WEDNESDAY. THIS SYSTEM HAS

A LOW CHANCE...10 PERCENT...OF BECOMING A SUBTROPICAL OR TROPICAL

CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES NORTHEASTWARD AT ABOUT

15 MPH.

Might get a bumb in the next TWO, but the phase digrams look pretty unimpressive.

GOES13152012206LPQjeY.jpg

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Hi all,

It appears the current intraseasonal state in the tropics shall remain unfavorable for any Atlantic hurricanes through early August. My real-time multivariate MJO indices suggests that the active convection associated with the MJO is currently located over the Maritime/Western Pacific sector. This is consistent with a time when conditions over the Atlantic are unfavorable for the genesis of tropical cyclones.

kelvinPhase.png

My last prediction on July 16 was for a lack of TC activity through August 2, with an uptick in tropical cyclone activity between August 3-13. This forecast is based off the location of active convection associated with a strong eastward propagating convectively-coupled atmospheric Kelvin wave which is currently at the longitude of the Indian Basin. The superposition between this CCKW and the active convection of the MJO suggests that we might see an amplification of the RMM PCs into RMM phase 6 later this week, with counterclockwise through the western Hemisphere. Of course... this remains to be seen!

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Way too much SAL for any chance of development within the MDR at this time. Check back in a couple of weeks after a couple of more waves roll off Africa and perhaps moisten things up abit...;)

post-32-0-92727000-1343140571_thumb.jpg

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^^

Yeah, but we still may have to watch these next few systems. They have the potential to become "sleeper waves" and develop further down the road.

Such a waste of a strong AEW.

WMBds124.png

Sleepers are a good thing, judging from Euro ensemble 500 mb heights, which suggests Day 9 and Day 10 the East Coast trough might retrograde back a bit West. Nothing will be able to hit Florida if it is already near/North of the Antilles at Day 10 if the Euro ensembles are right, but would perhaps be a Florida threat if they can stay undeveloped and at a lower latitude. Just looking for the silver lining possibilities that could take a potential fish, if it develops right away, and get it to Florida or the SE Coast by virtue of later development.

ETA: The later=better is generalizing, of course, a system that passes the Lesser Antilles and then gets torn apart crossing Hispaniola trying to get to Florida, doesn't do anyone any good, but 10 days out, dealing in generalities.

ETA II - Looking at Gulf satellite, the old Florida lemon, while not super impressive, is still off the Panhandle. Also mildly nervous about the lemon ruining my 0/0/0 for July. Looks frontal on the satellite, but for a frontal low, doesn't look terrible. If it completely occludes and has decent storm action, hard to predict if someone will slap a name on it.

post-138-0-40125900-1343146218_thumb.gif

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Im terribly sorry for this Josh. :axe:

Another non-tropical fish.

(Does look good though...)

20120724.1715.goes13.x.vis1km_high.98LINVEST.35kts-1007mb-360N-550W.100pc.jpg

BEGIN

NHC_ATCF

invest_al982012.invest

FSTDA

R

U

040

010

0000

201207241720

NONE

NOTIFY=ATRP

END

INVEST, AL, L, , , , , 98, 2012, DB, O, 2012072418, 9999999999, , , , , , METWATCH, , AL982012

AL, 98, 2012072406, , BEST, 0, 350N, 560W, 25, 1009, DB, 0, , 0, 0, 0, 0,

AL, 98, 2012072412, , BEST, 0, 355N, 555W, 35, 1009, DB, 0, , 0, 0, 0, 0,

AL, 98, 2012072418, , BEST, 0, 360N, 550W, 35, 1007, LO, 34, NEQ, 0, 30, 40, 40, 1013, 100, 35, 0, 0, L, 0, , 0, 0, INVEST, M,

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