Tropical Storm NATE

ZCZC MIATCDAT5 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM NATE DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT TUE SEP 06 2005
 
A PLETHORA OF SATELLITE MICROWAVE DATA OVER THE PAST 12 HOURS
INDICATES NATE HAD BEEN MOVING SLOWLY EASTWARD BEFORE STALLING
DURING THE PAST FEW HOURS. THE CENTER IS UNDERNEATH THE NORTHWEST
PORTION OF THE CONVECTIVE CLOUD MASS...DUE TO SOME NORTHERLY
MID-LEVEL FLOW UNDERCUTTING THE FAVORABLE UPPER-LEVEL OUTFLOW
LAYER. THE INITIAL INTENSITY OF 40 KT IS BASED ON A BLEND OF
SATELLITE INTENSITY ESTIMATES OF 45 KT FROM TAFB AND 35 KT FROM
SAB...AND THE IMPROVED CONVECTIVE BANDING FEATURES NOTED IN THE
MICROWAVE DATA.
 
THE INITIAL MOTION ESTIMATE IS 275/02...BUT THE CYCLONE COULD EASILY
BE QUASI-STATIONARY. NATE IS TRAPPED IN A WEAK STEERING FLOW
PATTERN BETWEEN HURRICANE MARIA TO THE NORTHEAST AND A DEVELOPING
DISTURBANCE OVER THE NORTHWEST BAHAMAS. MODERATE NORTHERLY
MID-LEVEL FLOW ON THE EAST SIDE OF A SUBTROPICAL RIDGE LOCATED
BETWEEN BERMUDA AND THE SOUTHEASTERN U.S. IS FORECAST TO GRADUALLY
WEAKEN AS IT SLIDES SLOWLY EASTWARD OVER THE NEXT COUPLE OF DAYS.
THIS SHOULD GRADUALLY INDUCE A WESTWARD MOTION UNTIL A SHORTWAVE
TROUGH MOVES OFF THE SOUTHEASTERN U.S. AND COMPLETELY ERODES THE
RIDGE AND LIFTS OUT NATE FAIRLY QUICKLY TO THE NORTHEAST. ALL OF
THE GLOBAL MODELS AND THE GFDL MODEL ARE IN GOOD AGREEMENT ON THIS
DEVELOPING STEERING PATTERN. AS A RESULT...THE FORECAST TRACK HAD
TO BE SHIFTED MORE TO THE RIGHT AND MUCH FASTER THAN THE PREVIOUS
TWO ADVISORIES WERE INDICATING. THE CAUSE FOR THE FASTER MOTION IS
LIKELY DUE TO THE MODELS NOW INITIALIZING AND MAINTAINING A MORE
VERTICALLY DEEP AND STRONGER SYSTEM THAN IN PREVIOUS MODELS RUNS.
THIS FASTER MOTION NOW PLACES BERMUDA UNDER THE THREAT OF POSSIBLE
TROPICAL STORM-FORCE OR HURRICANE-FORCE WINDS IN ABOUT 72 HOURS.
 
NATE IS FORECAST TO REMAIN IN A VERY LOW SHEAR ENVIRONMENT AND OVER
SSTS OF 29C FOR THE NEXT 36 HOURS. WITH SUCH A TIGHT LOW-LEVEL
INNER CORE WIND FIELD...THESE CONDITIONS WOULD USUALLY FAVOR RAPID
INTENSIFICATION TO OCCUR. HOWEVER...THE NORTHERLY MID-LEVEL FLOW
UNDERCUTTING THE FAVORABLE OUTFLOW LAYER MAY RESULT IN SOME SHEAR
CONDITIONS AND OCCASIONAL INTRUSIONS OF DRY AIR FOR THE NEXT 24
HOURS. AS A RESULT...ONLY MODEST STRENGTHENING AT A TYPICAL RATE OF
20 KT PER 24 HOURS IS FORECAST THROUGH 36 HOURS. AFTERWARDS...
INCREASING WEST TO WEST-SOUTHWESTERLY UPPER-LEVEL SHEAR AHEAD OF AN
APPROACHING DEEP-LAYER TROUGH SHOULD CAP THE INTENSIFICATION
PROCESS AND INDUCE A SLOW WEAKENING TREND.

FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      06/0900Z 28.6N  66.6W    40 KT
 12HR VT     06/1800Z 28.7N  67.0W    50 KT
 24HR VT     07/0600Z 29.0N  67.4W    60 KT
 36HR VT     07/1800Z 29.4N  68.0W    70 KT
 48HR VT     08/0600Z 30.3N  68.3W    70 KT
 72HR VT     09/0600Z 32.0N  66.8W    65 KT
 96HR VT     10/0600Z 34.0N  62.0W    60 KT
120HR VT     11/0600Z 38.5N  52.0W    55 KT

$$
NNNN