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TROPICAL STORM OLGA DISCUSSION NUMBER  35
NATIONAL WEATHER SERVICE MIAMI FL
4 AM EST MON DEC 03 2001
 
OLGA HAS RE-DEVELOPED A SMALL BURST OF MODERATE TO DEEP CONVECTION 
OVER AND JUST EAST OF THE LOW-LEVEL CENTER.  SHIP KIRF TRAVERSED THE 
CENTER OF OLGA AROUND 03Z AND REPORTED 28 KT WINDS AND A PRESSURE OF 
1009.5 MB ABOUT 70 NM SOUTH-SOUTHEAST OF THE CENTER AT 06Z...OUTSIDE 
OF ANY CONVECTION. AS SUCH...THE INITIAL INTENSITY IS BEING HELD AT 
35 KT SINCE SOME STRONGER WINDS MAY EXIST IN THE CONVECTIVE AREAS 
CLOSER TO THE CENTER.  OUTFLOW IS FAIR TO THE EAST AND RESTRICTED TO 
THE WEST DUE TO INCREASING UPPER-LEVEL WESTERLY SHEAR.
 
THE INITIAL MOTION ESTIMATE IS 360/04.  THERE IS NO SIGNIFICANT 
CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING.  THE UPPER-LEVEL 
SHORTWAVE TROUGH THAT HAS BEEN MOVING RAPIDLY EASTWARD OFF THE U.S. 
EAST COAST THE PAST 12 HOURS IS NOW LOCATED ALMOST DUE NORTH OF 
OLGA. IT APPEARS UNLIKELY THAT THE TROUGH WILL PICK UP AND RECURVE 
OLGA NORTHEASTWARD INTO THE FAST POLAR WESTERLIES...AND FINALLY END 
THE 2001 ATLANTIC HURRICANE SEASON. THE SHORTWAVE TROUGH WILL 
INSTEAD ONLY ACT TO WEAKEN THE MID-LEVEL STEERING FLOW AND CAUSE 
OLGA TO BECOME STATIONARY OR MAKE A SMALL ANTICYCLONIC LOOP DURING 
THE NEXT 24 TO 36 HOURS.  AFTER THAT...IF OLGA SURVIVES THE 
INCREASING WESTERLY TO NORTHERLY UPPER-LEVEL SHEAR...THEN THE 
CYCLONE SHOULD TURN BACK TO THE WEST OR SOUTHWEST UNDER THE 
INFLUENCE OF THE STRENGTHENING LOW- TO MID-LEVEL SUBTROPICAL RIDGE 
TO THE NORTH OF OLGA.  SINCE THE NHC MODEL GUIDANCE LOOKS LIKE A 
SQUASHED SPIDER WITH FORECASTS HEADED IN JUST ABOUT EVERY DIRECTION 
POSSIBLE...A SLOW FORWARD SPEED FOR THE NEXT 36 TO 48 HOURS APPEARS 
TO BE IN ORDER.  NO ONE PARTICULAR MODEL STANDS OUT AS HAVING A GOOD 
HANDLE ON THE FUTURE TRACK OF OLGA...INCLUDING THE NOGAPS MODEL 
WHICH NO LONGER BRINGS OLGA ACROSS THE NORTHERN BAHAMAS AND SOUTH 
FLORIDA IN 72 HOURS. THEREFORE...THE OFFICIAL FORECAST REMAINS CLOSE 
TO THE PREVIOUS TRACK AND IS CONSISTENT WITH THE EVOLVING SYNOPTIC 
PATTERN AND BLOCKING SURFACE TO MID-LEVEL RIDGE PATTERN. 

WATER VAPOR IMAGERY INDICATES THE APPROACHING SHORTWAVE TROUGH IS 
PUTTING PRESSURE ON THE WEST SIDE OF OLGA AND IS CREATING A SHEARING 
PATTERN WITH ALL OF THE CONVECTION BEING DISPLACED TO THE EAST. 
THERE MAY BE SOME MINOR FLUCTUATIONS IN INTENSITY AND OLGA COULD 
EVEN WEAKEN BACK TO A DEPRESSION LATER TODAY. BUT FOR THE MOST 
PART...LITTLE CHANGE IN STRENGTH IS EXPECTED DURING THE PERIOD. IF 
OLGA SURVIVES THE NEXT 48 HOURS...ALL OF THE GLOBAL MODELS ARE STILL 
FORECASTING THE UPPER-LEVEL FLOW TO WEAKEN AND ALSO DEVELOP A 200 MB 
ANTICYCLONE TO THE NORTHEAST OF THE BAHAMAS. THIS WOULD PLACE OLGA 
IN A MORE FAVORABLE ENVIRONMENT FOR STRENGTHENING BY 48 TO 72 HOURS 
...IF THE CYCLONE MOVES WESTWARD FASTER THAN THE CURRENT FORECAST.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     03/0900Z 27.6N  69.9W    35 KTS
12HR VT     03/1800Z 28.2N  69.8W    35 KTS
24HR VT     04/0600Z 28.6N  69.4W    35 KTS
36HR VT     04/1800Z 28.5N  68.8W    35 KTS
48HR VT     05/0600Z 28.0N  69.5W    35 KTS
72HR VT     06/0600Z 27.5N  70.5W    30 KTS
 
 
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