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Post-Tropical Cyclone HUMBERTO (Text)

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POST-TROPICAL CYCLONE HUMBERTO DISCUSSION NUMBER  24
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092013
1100 AM AST SAT SEP 14 2013
 
HUMBERTO CONTINUES TO MAINTAIN A LARGE AND WELL-DEFINED
CIRCULATION...BUT HAS BEEN WITHOUT ORGANIZED DEEP CONVECTION FOR
ABOUT 24 HOURS.  GIVEN THE LACK OF DEEP CONVECTION...HUMBERTO IS
BEING DECLARED A POST-TROPICAL CYCLONE ON THIS ADVISORY...WITH
WINDS ESTIMATED TO BE 35 KT BASED ON A RECENT ASCAT PASS.  VERY
STRONG WEST-SOUTHWESTERLY SHEAR...DRY MID-TROPOSPHERIC AIR...AND A
TRACK OVER MARGINALLY WARM SEA SURFACE TEMPERATURES COULD RESULT IN
A CONTINUED GRADUAL SPIN-DOWN OF THE CYCLONE DURING THE NEXT DAY OR
POSSIBLY TWO.  AFTER THAT...REGENERATION OF HUMBERTO INTO A
TROPICAL CYCLONE SEEMS LIKELY SINCE THE CYCLONE WILL BE MOVING OVER
WARMER WATERS AND EXPERIENCING A GRADUAL DECREASE IN SHEAR.  GLOBAL
MODELS SHOW HUMBERTO INTERACTING WITH A LARGE MID-LATITUDE TROUGH
IN ABOUT 3 DAYS. THIS INTERACTION COULD BE THE IMPETUS FOR A FASTER
RATE OF INTENSIFICATION LATE IN THE FORECAST PERIOD.  THE NHC
INTENSITY PREDICTION IS KEPT HIGHER INITIALLY ASSUMING A SLOWER
RATE OF DECAY.  THE EXTENDED FORECAST IS KEPT THE SAME AND IS
SLIGHTLY ABOVE THE BULK OF THE INTENSITY GUIDANCE.
 
THE POST-TROPICAL CYCLONE IS MOVING WEST-NORTHWESTWARD...285/11...
AROUND A LOW- TO MID-LEVEL RIDGE OVER THE NORTHEASTERN ATLANTIC. THE
FORWARD MOTION OF HUMBERTO SHOULD GRADUALLY TURN NORTHWESTWARD AND
SLOW DOWN DURING THE NEXT COUPLE OF DAYS WHEN IT MOVES INTO A
WEAKNESS OVER THE CENTRAL ATLANTIC. A STRONG TROUGH IN THE
WESTERLIES APPROACHING HUMBERTO IN ABOUT 3 DAYS SHOULD LEAD TO A
TURN NORTHEASTWARD WITH ACCELERATION ON DAYS 4 AND 5. THE NHC TRACK
FORECAST IS ABOUT THE SAME AS BEFORE BUT SLOWER ON DAYS 3 TO 5...
LYING IN BETWEEN THE ECMWF AND GFS AND CLOSE TO THE MULTI-MODEL
CONSENSUS TVCA.
 
ADDITIONAL INFORMATION ON HUMBERTO CAN BE FOUND IN HIGH SEAS
FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS
HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/1500Z 25.4N  35.4W   35 KT  40 MPH...POST-TROPICAL
 12H  15/0000Z 25.8N  37.1W   30 KT  35 MPH...POST-TROP/REMNT LOW
 24H  15/1200Z 26.7N  39.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  16/0000Z 27.5N  41.2W   35 KT  40 MPH...POST-TROPICAL
 48H  16/1200Z 28.6N  42.6W   35 KT  40 MPH...POST-TROPICAL
 72H  17/1200Z 30.9N  44.1W   45 KT  50 MPH
 96H  18/1200Z 33.7N  44.1W   55 KT  65 MPH
120H  19/1200Z 37.5N  41.5W   65 KT  75 MPH
 
$$
FORECASTER KIMBERLAIN
 
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