ATL: SEAN - Post-Tropical - Discussion

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Re: ATL: SEAN - Tropical Storm - Discussion

#121 Postby Epsilon_Fan » Thu Nov 10, 2011 3:48 pm

Looks like he is past peak... the cloud pattern looks like shear is impacting it
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Re: ATL: SEAN - Tropical Storm - Discussion

#122 Postby wxman57 » Thu Nov 10, 2011 3:58 pm

Probably not more than 24 more hours of "life" for Sean (as a TC). That should put the 2011 season to bed...
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Re: ATL: SEAN - Advisories

#123 Postby cycloneye » Thu Nov 10, 2011 6:46 pm

BULLETIN
TROPICAL STORM SEAN INTERMEDIATE ADVISORY NUMBER 11A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192011
800 PM AST THU NOV 10 2011

...SEAN EXPECTED TO PASS NORTHWEST OF BERMUDA EARLY FRIDAY...


SUMMARY OF 800 PM AST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...31.0N 69.0W
ABOUT 265 MI...425 KM WSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...ENE OR 70 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...983 MB...29.03 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* BERMUDA

INTERESTS IN BERMUDA SHOULD MONITOR PRODUCTS ISSUED BY THE BERMUDA
WEATHER SERVICE.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 800 PM AST...0000 UTC...THE CENTER OF TROPICAL STORM SEAN WAS
LOCATED NEAR LATITUDE 31.0 NORTH...LONGITUDE 69.0 WEST. SEAN HAS
BEEN TOWARD THE EAST-NORTHEAST NEAR 13 MPH...20 KM/H...OVER THE
PAST COUPLE OF HOURS. HOWEVER...A NORTHEASTWARD MOTION IS EXPECTED
TO RESUME TONIGHT AND CONTINUE FOR THE NEXT COUPLE OF DAYS WITH AN
INCREASE IN FORWARD SPEED. ON THE FORECAST TRACK...THE CENTER OF
THE SEAN SHOULD PASS TO THE NORTHWEST OF BERMUDA FRIDAY MORNING.

MAXIMUM SUSTAINED WINDS ARE NEAR 65 MPH...100 KM/H...WITH HIGHER
GUSTS. LITTLE CHANGE IN STRENGTH IS EXPECTED TONIGHT...AND SLOW
WEAKENING IS FORECAST ON FRIDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 255 MILES...410 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 983 MB...29.03 INCHES.


HAZARDS AFFECTING LAND
----------------------
WIND...TROPICAL STORM CONDITIONS ARE EXPECTED TO BEGIN ON BERMUDA
LATE THIS EVENING.

RAINFALL...SEAN IS EXPECTED TO PRODUCE 1 TO 3 INCHES OF RAIN ON
BERMUDA.

SURF...SWELLS GENERATED BY SEAN ARE AFFECTING PORTIONS OF THE
SOUTHEASTERN COAST OF THE UNITED STATES AND BERMUDA...CAUSING
LIFE-THREATENING SURF AND RIP CURRENTS. PLEASE SEE STATEMENTS FROM
YOUR LOCAL NATIONAL WEATHER SERVICE OFFICE FOR MORE DETAILS.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 PM AST.

$$
FORECASTER BRENNAN
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Re: ATL: SEAN - Advisories

#124 Postby cycloneye » Thu Nov 10, 2011 9:42 pm

TROPICAL STORM SEAN DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192011
1100 PM AST THU NOV 10 2011

SATELLITE TRENDS HAVE PROVIDED MIXED SIGNALS REGARDING THE INTENSITY
OF SEAN OVER THE PAST FEW HOURS. ON ONE HAND...VERTICAL SHEAR OF
ABOUT 20 KT AS ANALYZED BY UW-CIMSS HAS DISPLACED THE MID-LEVEL
CENTER EAST OF THE LOW-LEVEL CENTER...AS SEEN IN RECENT MICROWAVE
IMAGERY FROM THE FNMOC TC WEBPAGE. HOWEVER...CONVECTIVE CLOUD TOPS
HAVE COOLED AND EXPANDED IN COVERAGE OVER THE PAST FEW HOURS.
THEREFORE...THE INITIAL INTENSITY WILL BE HELD AT 55 KT IN
AGREEMENT WITH 00Z DVORAK CI-NUMBERS FROM TAFB AND SAB. THE NHC
FORECAST SHOWS NO CHANGE IN INTENSITY DURING THE NEXT 12 HOURS...IN
AGREEMENT WITH MOST OF THE GUIDANCE. BY 24 HOURS...SEAN SHOULD BE
ABSORBED BY THE FRONTAL BOUNDARY NOW MOVING OFFSHORE OF THE EAST
COAST OF THE UNITED STATES.

RECENT DVORAK AND MICROWAVE FIXES SUGGEST THAT THE LOW-LEVEL CENTER
HAS BEEN MOVING A BIT TO THE RIGHT OF THE PREVIOUS FORECAST...WITH
AN INITIAL MOTION OF 060/11. THIS RIGHTWARD JOG SHOULD BE TEMPORARY
HOWEVER...AS ALL OF THE GUIDANCE SHOWS A NORTHEASTWARD MOTION
DEVELOPING OVERNIGHT AS THE DEEP-LAYER FLOW BECOMES SOUTHWESTERLY
AHEAD OF THE MID/UPPER-LEVEL TROUGH MOVING OFF THE U.S. EAST COAST.
GIVEN THE INITIAL POSITION AND MOTION...THE NEW NHC TRACK FORECAST
HAS BEEN ADJUSTED TO THE RIGHT...OR SOUTHEAST...OF THE PREVIOUS
ONE...AND LIES A LITTLE TO THE RIGHT OF THE GFS AND ECMWF AND CLOSE
TO THE GEFS ENSEMBLE MEAN.


FORECAST POSITIONS AND MAX WINDS

INIT 11/0300Z 31.5N 68.2W 55 KT 65 MPH
12H 11/1200Z 33.6N 65.3W 55 KT 65 MPH
24H 12/0000Z...ABSORBED BY FRONT

$$
FORECASTER BRENNAN
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#125 Postby fci » Fri Nov 11, 2011 3:03 am

Still time for one of those Central Far Eastern Atlantic storms.
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Re: ATL: SEAN - Advisories

#126 Postby cycloneye » Fri Nov 11, 2011 5:28 am

TROPICAL STORM SEAN DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192011
500 AM AST FRI NOV 11 2011

SEAN IS SHOWING A SHEARED CLOUD PATTERN IN INFRARED AND TRMM
MICROWAVE SATELLITE IMAGERY THIS MORNING...WITH THE LOW-LEVEL
CENTER NEAR THE WESTERN EDGE OF THE CONVECTIVE OVERCAST. WHILE
SUBJECTIVE SATELLITE INTENSITY ESTIMATES FROM SAB AND TAFB ARE
UNCHANGED SINCE THE PREVIOUS ADVISORY...INTENSITY ESTIMATES FROM
THE AMSU MICROWAVE SOUNDER AND THE CIMSS ADVANCED DVORAK TECHNIQUE
HAVE DECREASED A LITTLE DURING THE PAST 6-12 HOURS. IN ADDITION...
AN ASCAT OVERPASS NEAR 0200 UTC SHOWED WINDS NEAR 45 KT IN THE
SOUTHEASTERN QUADRANT. BASED ON THESE DATA...THE INITIAL INTENSITY
IS DECREASED TO 50 KT. LITTLE CHANGE IN STRENGTH IS LIKELY BEFORE
SEAN GETS ABSORBED BY A FRONTAL SYSTEM IN 18-24 HOURS.

SEAN IS ACCELERATING TOWARD THE NORTHEAST ON THE SOUTH SIDE OF A
DEVELOPING DEEP-LAYER CYCLONE OVER NEW ENGLAND AND THE CANADIAN
MARITIMES...WITH THE INITIAL MOTION NOW 050/19. AN EVEN FASTER
MOTION TOWARD THE NORTHEAST IS EXPECTED DURING THE REMAINDER OF THE
LIFE OF THE CYCLONE.

THE WIND RADII HAVE BEEN REVISED BASED ON THE ASCAT DATA.

FORECAST POSITIONS AND MAX WINDS

INIT 11/0900Z 32.9N 66.3W 50 KT 60 MPH
12H 11/1800Z 35.2N 62.8W 50 KT 60 MPH
24H 12/0600Z...ABSORBED BY FRONTAL SYSTEM.

$$
FORECASTER BEVEN
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Re: ATL: SEAN - Tropical Storm - Discussion

#127 Postby wxman57 » Fri Nov 11, 2011 8:48 am

The end is near for Sean, as the cold front is just about to reach its center of circulation. Convection has been stripped away 100 miles to the east. Could be the end of the season.
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Re: ATL: SEAN - Advisories

#128 Postby cycloneye » Fri Nov 11, 2011 9:45 am

TROPICAL STORM SEAN DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192011
1100 AM AST FRI NOV 11 2011

SEAN IS A STRONGLY SHEARED TROPICAL CYCLONE WITH THE LOW-LEVEL
CENTER LOCATED ABOUT 70 N MI TO THE WEST OF THE SHRINKING DENSE
OVERCAST. SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB HAVE
DECREASED... AND THE INITIAL WIND SPEED IS LOWERED TO 45 KT. A COLD
FRONT... CURRENTLY SITUATED A COUPLE OF HUNDRED N MI TO THE WEST OF
SEAN...IS EXPECTED TO MERGE WITH THE CYCLONE LATER TODAY CAUSING IT
TO LOSE TROPICAL CHARACTERISTICS BY THEN.

THE TROPICAL STORM IS GAINING FORWARD SPEED...AND THE LATEST INITIAL
MOTION ESTIMATE IS 050/20. THE CENTER OF SEAN IS CURRENTLY PASSING
JUST NORTH OF BERMUDA...AND IT IS EXPECTED TO MOVE MORE RAPIDLY
NORTHEASTWARD OVER THE NORTH ATLANTIC UNTIL IT DISSIPATES TONIGHT
OR EARLY SATURDAY.

FORECAST POSITIONS AND MAX WINDS

INIT 11/1500Z 34.0N 64.1W 45 KT 50 MPH
12H 12/0000Z 37.2N 59.9W 45 KT 50 MPH...POST-TROP/EXTRATROP
24H 12/1200Z...DISSIPATED

$$ FORECASTER CANGIALOSI/STEWART
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Re: ATL: SEAN - Advisories

#129 Postby cycloneye » Fri Nov 11, 2011 3:40 pm

BULLETIN
TROPICAL STORM SEAN ADVISORY NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192011
500 PM AST FRI NOV 11 2011

...SEAN EXPECTED TO BECOME POST-TROPICAL BY TONIGHT...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...35.5N 61.3W
ABOUT 300 MI...480 KM NE OF BERMUDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...NE OR 55 DEGREES AT 30 MPH...48 KM/H
MINIMUM CENTRAL PRESSURE...991 MB...29.26 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

THE BERMUDA WEATHER SERVICE HAS DISCONTINUED THE TROPICAL STORM
WARNING FOR BERMUDA.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 500 PM AST...2100 UTC...THE CENTER OF TROPICAL STORM SEAN WAS
LOCATED NEAR LATITUDE 35.5 NORTH...LONGITUDE 61.3 WEST. SEAN IS
MOVING TOWARD THE NORTHEAST NEAR 30 MPH...48 KM/H...AND THIS GENERAL
MOTION IS EXPECTED TO CONTINUE THROUGH TONIGHT.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 50 MPH...85 KM/H...WITH HIGHER
GUSTS. LITTLE CHANGE IN STRENGTH IS FORECAST BEFORE SEAN IS
ABSORBED INTO A FRONTAL SYSTEM TONIGHT OR EARLY SATURDAY.

TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 175 MILES...280 KM
FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 991 MB...29.26 INCHES.


HAZARDS AFFECTING LAND
----------------------
SURF...SWELLS GENERATED BY SEAN ARE AFFECTING BERMUDA...CAUSING
LIFE-THREATENING SURF AND RIP CURRENTS. THESE SWELLS SHOULD
GRADUALLY DIMINISH DURING THE NEXT DAY OR SO.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 PM AST.

$$
FORECASTER CANGIALOSI


TROPICAL STORM SEAN DISCUSSION NUMBER 15...RETRANSMITTED
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192011
500 PM AST FRI NOV 11 2011

SEAN IS QUICKLY LOSING TROPICAL CHARACTERISTICS. VISIBLE SATELLITE
IMAGES SHOW STABLE STRATOCUMULUS CLOUDS ENTRAINING INTO THE
SOUTHERN HALF OF THE CIRCULATION. THIS STABLE AIR IS ALSO EVIDENT
IN SURFACE OBSERVATIONS...WITH THE DEWPOINT IN BERMUDA FALLING
ABOUT 3C DURING THE LAST FEW HOURS. MEANWHILE...A RAGGED CURVED
BAND OF CONVECTION STILL EXISTS ON THE EAST SIDE OF THE
CIRCULATION...AND THAT IS THE BASIS FOR MAINTAINING ADVISORIES ON
THIS SYSTEM. NONETHELESS...SEAN IS EXPECTED TO BECOME POST-TROPICAL
SOON AND WILL LIKELY BE ABSORBED BY A COLD FRONT...WHICH IS NOW
VERY NEAR THE CYCLONE...TONIGHT OR EARLY SATURDAY.

SEAN IS RACING NORTHEASTWARD AND SHOULD CONTINUE MOVING IN THAT
DIRECTION OVER THE NORTH ATLANTIC UNTIL DISSIPATION.

FORECAST POSITIONS AND MAX WINDS

INIT 11/2100Z 35.5N 61.3W 45 KT 50 MPH
12H 12/0600Z 38.2N 56.2W 45 KT 50 MPH...POST-TROP/EXTRATROP
24H 12/1800Z...DISSIPATED

$$
FORECASTER CANGIALOSI
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Re: ATL: SEAN - Tropical Storm - Discussion

#130 Postby cycloneye » Fri Nov 11, 2011 7:56 pm

00z Best Track puts the obituary on Sean.

AL, 19, 2011111200, , BEST, 0, 359N, 594W, 35, 1000, PT

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 011.invest
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Re: ATL: SEAN - Advisories

#131 Postby cycloneye » Fri Nov 11, 2011 9:34 pm

POST-TROPICAL CYCLONE SEAN DISCUSSION NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192011
1100 PM AST FRI NOV 11 2011


ALTHOUGH THERE IS A BAND OF THUNDERSTORM TO THE EAST OF THE AREA OF
LOWEST PRESSURE...ALL INDICATIONS ARE THAT SEAN HAS BECOME A
POST-TROPICAL CYCLONE...AND HAS MERGED WITH A COLD FRONT. THE
CYCLONE IS MOVING RAPIDLY TO THE EAST-NORTHEAST AND WILL CONTINUE
ON THIS TRACK UNTIL DISSIPATION ON SATURDAY. THIS IS THE LAST
ADVISORY ISSUED BY THE NATIONAL HURRICANE CENTER ON SEAN.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0300Z 36.7N 57.7W 35 KT 40 MPH...POST-TROP/EXTRATROP
12H 12/1200Z 39.0N 52.5W 30 KT 35 MPH...POST-TROP/EXTRATROP
24H 13/0000Z...DISSIPATED

$$
FORECASTER AVILA
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