[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 191438
TCDAT3

HURRICANE GORDON DISCUSSION NUMBER  16
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL082012
1100 AM AST SUN AUG 19 2012

THE EYE OF GORDON IS INTERMITTENTLY VISIBLE IN GEOSTATIONARY
IMAGERY...BUT HAS BEGUN TO SHRINK AND BECOME LESS DISTINCT OVER THE
PAST FEW HOURS. AN 1103 UTC SSMIS PASS FROM THE FNMOC TC WEBPAGE
SHOWS THAT THE EYEWALL HAS OPENED UP ON THE SOUTH SIDE. THE
CIRCULATION ALSO APPEARS TO BE TILTING EASTWARD WITH HEIGHT...
LIKELY DUE TO THE ALMOST 30 KT OF SHEAR ANALYZED OVER GORDON BY
UW-CIMSS. THE INITIAL INTENSITY HAS BEEN LOWERED TO 85 KT FOR THIS
ADVISORY BASED ON A BLEND OF THE LATEST DVORAK ESTIMATES FROM TAFB
AND SAB...AND THIS COULD BE A LITTLE GENEROUS. STEADY WEAKENING IS
FORECAST SINCE GORDON WILL BE MOVING OVER COOLER SSTS WHILE THE
SHEAR REMAINS ABOVE 30 KT AS A SHORTWAVE TROUGH CURRENTLY NEAR
40N/40W OVERTAKES THE TROPICAL CYCLONE IN THE NEXT 36 HOURS. THE
NHC INTENSITY FORECAST HAS BEEN ADJUSTED DOWNWARD AND IS BETWEEN
THE LATEST DECAY SHIPS AND LGEM MODELS...BUT KEEPS GORDON AS A
HURRICANE AS IT PASSES NEAR THE EASTERN AZORES TOMORROW. THE GFS
AND ECMWF GLOBAL MODELS SHOW THE LOW- AND MID-LEVEL CIRCULATIONS OF
GORDON DECOPULING BY 48 HOURS...AND THE CYCLONE SHOULD BECOME
POST-TROPICAL AROUND THAT TIME. GORDON SHOULD BECOME A REMNANT LOW
BY 72 HOURS WITH DISSIPATION EXPECTED BY DAY 4.

THE INITIAL MOTION ESTIMATE IS 075/18. GORDON SHOULD CONTINUE
EAST-NORTHEASTWARD WITH A GRADUAL DECREASE IN FORWARD SPEED OVER
THE NEXT 48 HOURS AS THE CYCLONE INTERACTS WITH THE AFOREMENTIONED
SHORTWAVE. BEYOND THAT TIME A SLOWER EASTWARD MOTION IS EXPECTED
AFTER THE CIRCULATION DECOUPLES. THE TRACK MODEL GUIDANCE REMAINS
IN GOOD AGREEMENT ON THIS SCENARIO...AND THE NEW NHC FORECAST IS AN
UPDATE OF THE PREVIOUS ONE THROUGH 36 HOURS. AT 48 AND 72 HOURS THE
NHC TRACK IS A BIT SLOWER...TRENDING TOWARD THE MULTI-MODEL
CONSENSUS AIDS AND THE ECMWF.

FORECAST POSITIONS AND MAX WINDS

INIT  19/1500Z 35.5N  29.7W   85 KT 100 MPH
 12H  20/0000Z 36.5N  26.8W   75 KT  85 MPH
 24H  20/1200Z 38.0N  23.6W   60 KT  70 MPH
 36H  21/0000Z 39.2N  20.8W   50 KT  60 MPH
 48H  21/1200Z 39.5N  19.0W   40 KT  45 MPH...POST-TROPICAL
 72H  22/1200Z 39.5N  17.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  23/1200Z...DISSIPATED

$$
FORECASTER BRENNAN
 
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