Tropical Storm GAMMA

ZCZC MIATCDAT2 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM GAMMA DISCUSSION NUMBER  14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
4 AM EST SAT NOV 19 2005
 
SINCE THE LAST RECON FLIGHT... DEEP CONVECTION HAS REDEVELOPED OVER
AND NORTH OF THE LOW-LEVEL CENTER... AND HAS ALSO BECOME BETTER
ORGANIZED. THE INITIAL INTENSITY REMAINS AT 40 KT FOR THIS ADVISORY
BASED ON A BLEND OF SATELLITE INTENSITY ESTIMATES OF T3.0/45 KT
FROM TAFB AND T2.5/35 KT FROM SAB AND AFWA.

THE INITIAL MOTION ESTIMATE IS 325/05. UPPER-AIR DATA AT 00Z...
ALBEIT LIMITED ACROSS THE CARIBBEAN AREA EXCEPT FOR BELIZE...
INDICATE A BREAK IN THE 500 MB AND 400 MB RIDGE AXES ACROSS THE
NORTHWESTERN CARIBBEAN SEA...YUCATAN CHANNEL... WESTERN CUBA AND
SOUTHEASTERN GULF OF MEXICO. A WEAKNESS IN THE RIDGE TO THE NORTH
OF GAMMA IS ALSO BEGINNING TO APPEAR AT THE 700 MB LEVEL. THE
COMBINATION OF THE WEAKENING RIDGE ALONG 85W LONGITUDE AND THE
MODERATE TO STRONG UPPER-LEVEL SOUTHERLY FLOW ACROSS THE WESTERN
CARIBBEAN SHOULD OPEN AN ALLEY FOR GAMMA TO MOVE NORTHWARD THROUGH
OVER THE NEXT COUPLE OF DAYS. AFTER THAT... A SERIES OF SHORTWAVE
TROUGHS CURRENTLY OVER THE U.S. PLAINS STATES ARE FORECAST BY ALL
THE MODELS TO MERGE AND DEVELOP INTO A HIGH-AMPLITUDE TROUGH OVER
THE EASTERN U.S. AND THE EASTERN GULF OF MEXICO BY 72 HOURS. THIS
FEATURE IS EXPECTED TO INDUCE SOUTHWESTERLY TO WESTERLY STEERING
FLOW NORTH OF 20N LATITUDE BY 60-72 HOURS... WHICH SHOULD RESULT IN
GAMMA LIFTING OUT TO THE NORTHEAST ACROSS WESTERN CUBA... THE
BAHAMAS... AND POSSIBLY SOUTH FLORIDA. THE GLOBAL MODELS DISSIPATE
GAMMA OR KEEP IT TRAPPED IN THE WESTERN CARIBBEAN SEA DURING THE
NEXT 5 DAYS... WHICH SEEMS UNREASONABLE GIVEN THE VERTICALLY DEEP
CIRCULATION NOTED IN THE 00Z UPPER-AIR DATA. AS SUCH...THE OFFICIAL
FORECAST TRACK LEANS MORE TOWARD THE GFDL SOLUTION SINCE THAT MODEL
MAINTAINS A DEEP TROPICAL CYCLONE THROUGH 120 HOURS.
 
SINCE SIGNIFICANT VERTICAL SHEAR IS FORECAST TO REMAIN ACROSS GAMMA
THROUGHOUT THE PERIOD... ONLY SLIGHT INTENSIFICATION IS EXPECTED.
THE OFFICIAL FORECAST IS A BLEND OF THE GFDL AND SHIPS MODELS.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/0900Z 16.9N  86.2W    40 KT
 12HR VT     19/1800Z 17.5N  86.7W    45 KT
 24HR VT     20/0600Z 18.4N  86.8W    45 KT
 36HR VT     20/1800Z 20.0N  86.3W    45 KT
 48HR VT     21/0600Z 22.0N  84.3W    45 KT
 72HR VT     22/0600Z 26.0N  79.0W    45 KT...BECOMING EXTRATROPICAL
 96HR VT     23/0600Z 38.0N  67.0W    40 KT...EXTRATROPICAL
120HR VT     24/0600Z...ABSORBED BY LARGER EXTRATROPICAL LOW
  
$$
NNNN