ATL: SEAN - Post-Tropical - Discussion

[cycloneye]

Will this be named Subtropical Storm Sean?

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invest_al982011.invest
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201111060600
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INVEST, AL, L, , , , , 98, 2011, DB, O, 2011110606, 9999999999, , , , , , METWATCH, , AL982011
AL, 98, 2011110506, , BEST, 0, 330N, 738W, 45, 1005, EX, 34, NEQ, 450, 100, 200, 450,
AL, 98, 2011110512, , BEST, 0, 312N, 725W, 45, 1005, EX, 34, NEQ, 425, 0, 175, 425,
AL, 98, 2011110518, , BEST, 0, 298N, 711W, 45, 1005, EX, 34, NEQ, 400, 0, 175, 400,
AL, 98, 2011110600, , BEST, 0, 287N, 698W, 45, 1005, EX, 34, NEQ, 400, 0, 160, 400, 0, 0, 160, 0, 0,
AL, 98, 2011110606, , BEST, 0, 282N, 688W, 45, 1005, EX

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT SUN NOV 6 2011

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

A LARGE NON-TROPICAL LOW PRESSURE SYSTEM LOCATED ABOUT 400 MILES
SOUTHWEST OF BERMUDA IS PRODUCING AN EXTENSIVE AREA OF GALE-FORCE
WINDS OVER THE CENTRAL ATLANTIC. ALTHOUGH SHOWERS AND THUNDERSTORMS
ARE CURRENTLY LIMITED NEAR THE CENTER...THIS SYSTEM COULD GRADUALLY
ACQUIRE SUBTROPICAL CHARACTERISTICS AS IT MOVES OVER WARMER WATER
DURING THE NEXT FEW DAYS. THIS SYSTEM HAS A LOW CHANCE...10
PERCENT...OF BECOMING A SUBTROPICAL CYCLONE DURING THE NEXT 48
HOURS AS IT MOVES SLOWLY TOWARD THE SOUTHEAST OR SOUTH. ADDITIONAL
INFORMATION ON THIS GALE AREA CAN BE FOUND IN HIGH SEAS FORECASTS
ISSUED BY THE NOAA NATIONAL WEATHER SERVICE UNDER AWIPS HEADER
NFDHSFAT1...AND UNDER WMO HEADER FZNT01 KWBC.

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

$$
FORECASTER STEWART

[cycloneye]

Nice (for now) extratropical swirl.Will it make the transition to subtropical or even pure tropical?

[TheEuropean]

GFDL:

WHXX04 KWBC 061142
CHGQLM
ATTENTION...NATIONAL HURRICANE CENTER
NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR
TROPICAL STORM INVEST 98L
INITIAL TIME 6Z NOV 6
DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.
FORECAST STORM POSITION
HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)
0 28.0 68.7 130./ 9.9
6 28.0 68.0 90./ 6.6
12 28.2 68.0 352./ 2.7
18 28.4 68.1 317./ 1.8
24 28.2 68.6 246./ 4.4
30 28.2 68.4 90./ 1.3
36 29.1 68.5 355./ 8.8
42 29.8 69.4 309./10.8
48 29.8 70.8 270./12.1
54 29.2 71.4 222./ 8.1
60 29.0 71.1 121./ 3.2
66 29.6 70.3 52./ 9.0
72 31.2 70.1 7./16.1
78 32.9 70.7 340./17.7
84 34.1 71.4 330./13.4
90 34.8 71.2 18./ 7.5
96 36.1 70.0 42./16.2
102 38.3 67.9 44./27.4
STORM DISSIPATED AT 102 HRS AT THE ABOVE PSN.

[cycloneye]

Uploaded by imageshack.us

[Frank2]

That's the low that moved off the SE coast last week, and the same feature the GFS showed as a stationary 1007 or 1005 mb low that eventually weakens and merges with a trough to the northeast...

Frank

[LarryWx]

This one is zzzzzzzzz/boring, an appropriate way to end this mostly nonexciting season if it turns out to tbe the last one.

[cycloneye]

Up to 20%.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
700 PM EST SUN NOV 6 2011

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

1. A NON-TROPICAL LOW PRESSURE SYSTEM LOCATED ABOUT 390 MILES
SOUTHWEST OF BERMUDA IS PRODUCING A LARGE AREA OF GALE-FORCE
WINDS OVER THE WEST-CENTRAL ATLANTIC. ALTHOUGH THE ASSOCIATED
THUNDERSTORM ACTIVITY REMAINS LIMITED...THE LOW COULD GRADUALLY
ACQUIRE SOME SUBTROPICAL CHARACTERISTICS DURING THE NEXT COUPLE OF
DAYS. THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF BECOMING A
SUBTROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES LITTLE OR
DRIFTS SLOWLY WESTWARD. ADDITIONAL INFORMATION ON THIS GALE AREA
CAN BE FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NOAA NATIONAL
WEATHER SERVICE UNDER AWIPS HEADER NFDHSFAT1...AND UNDER WMO HEADER
FZNT01 KWBC.

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

$$
FORECASTER STEWART
NNNN

[tolakram]

This low passed right over Cincinnati earlier in the week, gave us 2 inches of rain. Tropical transition would be interesting, but won't happen unless it moves further south, in my opinion.

http://tropic.ssec.wisc.edu/real-time/m ... /main.html

MIMIC-TPW seems to be showing the start of some kind of transition. Spin slowing down, moisture on the increase.

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[cycloneye]

Up to 40%

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
700 AM EST MON NOV 7 2011

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

A NON-TROPICAL LOW PRESSURE SYSTEM LOCATED ABOUT 400 MILES
SOUTHWEST OF BERMUDA IS PRODUCING GALE FORCE WINDS OVER AN AREA
EXTENDING SEVERAL HUNDRED MILES TO THE NORTH OF THE CENTER. THE
ASSOCIATED SHOWERS AND THUNDERSTORMS HAVE BECOME A LITTLE BETTER
ORGANIZED OVERNIGHT...AND THE LOW COULD ACQUIRE SUBTROPICAL
CHARACTERISTICS OVER THE NEXT DAY OR TWO. THIS SYSTEM HAS A MEDIUM
CHANCE...40 PERCENT...OF BECOMING A SUBTROPICAL CYCLONE DURING THE
NEXT 48 HOURS AS IT MOVES SLOWLY WESTWARD TODAY AND NORTHWESTWARD
ON TUESDAY. ADDITIONAL INFORMATION ON THIS GALE AREA CAN BE FOUND
IN HIGH SEAS FORECASTS ISSUED BY THE NOAA NATIONAL WEATHER SERVICE
UNDER AWIPS HEADER NFDHSFAT1...AND UNDER WMO HEADER FZNT01 KWBC.

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

$$
FORECASTER PASCH

[wxman57]

I'd say chances of it becoming an STS are up to 80-90% within the next 24-36 hrs. NHC is giving themselves only a 40% chance of naming it, however. It's certainly much better organized than Jose was. All it needs is for that convection to continue another 4-8 hrs near the center.

[cycloneye]

I agree 57 with your assesment.

[Macrocane]

So do I. It looks well on its way to become a subtropical cyclone, I always find the development of these systems very interesting.

[Hylian Auree]

Meh, the NHC should've gone with 40 or even 50% percent at 1 AM, and red by now. It already looked subtropical around 1 AM, and now it has the perfect, classic subtropical appearance.

[Cranica]

Yeah, unless conditions get hostile real fast we'll get a STS out of this.

[cycloneye]

I dont see center exposed.

[cycloneye]

12z Best Track changed from extratropical to a low pressure.

AL, 98, 2011110712, , BEST, 0, 277N, 690W, 40, 1005, LO

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 011.invest

[Buck]

This guy is looking strong enough for an upgrade, I would think.

[AJC3]

This guy is looking strong enough for an upgrade, I would think.

It's not about strength. It was pretty much a gale center within 12-18 hours after it emerged offshore the SE U.S. coast. The big question is how much "tropicality" the system has - i.e. whether it should be classified as an STC. You'll find that these systems that don't cleanly fall into one category will cause the most consternation, hand-wringing, and NHC-second-guessing of any cyclones on here. Like others, I think this one is well on its way to transitioning to a STC.

[cycloneye]

[cycloneye]

Up to 60%

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
100 PM EST MON NOV 7 2011

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

A NON-TROPICAL LOW PRESSURE SYSTEM LOCATED ABOUT 425 MILES
SOUTHWEST OF BERMUDA CONTINUES TO PRODUCE GALE FORCE WINDS OVER AN
AREA EXTENDING SEVERAL HUNDRED MILES TO THE NORTH OF THE CENTER.
THE ASSOCIATED SHOWERS AND THUNDERSTORMS CONTINUE TO SHOW SIGNS OF
ORGANIZATION...AND THE LOW COULD ACQUIRE SUBTROPICAL
CHARACTERISTICS TONIGHT OR ON TUESDAY. THIS SYSTEM HAS A HIGH
CHANCE...60 PERCENT...OF BECOMING A SUBTROPICAL CYCLONE DURING THE
NEXT 48 HOURS AS IT MOVES SLOWLY WESTWARD TODAY AND NORTHWESTWARD
ON TUESDAY. ADDITIONAL INFORMATION ON THIS GALE AREA CAN BE FOUND
IN HIGH SEAS FORECASTS ISSUED BY THE NOAA NATIONAL WEATHER SERVICE
UNDER AWIPS HEADER NFDHSFAT1...AND UNDER WMO HEADER FZNT01 KWBC.

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

$$
FORECASTER PASCH