HOME	ARCHIVES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

ZCZC MIATCDAT2 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM OLGA DISCUSSION NUMBER  30
NATIONAL WEATHER SERVICE MIAMI FL
10 PM EST SAT DEC 01 2001
 
DURING THE PAST 6 HOURS...DEEP CONVECTION HAS RE-DEVELOPED NEAR THE 
CENTER AND OVER MUCH OF THE EASTERN SEMICIRCLE OF OLGA.  DVORAK 
SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE BOTH 35 KT...
T2.5...WITH DATA-T NUMBERS OF T3.0...OR 45 KT.  AS SUCH...OLGA HAS 
RE-STRENGTHENED BACK TO TROPICAL STORM STATUS.  OUTFLOW IS FAIR 
TO GOOD IN THE EASTERN SEMICIRCLE AND RESTRICTED TO THE WEST DUE TO 
MODERATE UPPER-LEVEL SOUTHWESTERLY SHEAR.
 
THE INITIAL MOTION ESTIMATE IS 320/05.  OLGA HAS ACTUALLY MOVED
LITTLE DURING THE PAST 12 HOURS OR SO.  A MID- TO UPPER-LEVEL
VORTICITY CENTER CAN BEEN SEEN IN WATER VAPOR IMAGERY DROPPING
SOUTHWARD JUST TO THE WEST OF OLGA.  THIS APPEARS TO BE INDUCING
SOME BINARY INTERACTION MOTION ONCE AGAIN...AND CAUSING THE CYCLONE
TO MOVE NORTHWARD AND NOW NORTHWESTWARD.  AS THE VORTICITY MAXIMUM
DROPS FARTHER SOUTH...OLGA SHOULD TURN BACK MORE TOWARD THE
WEST-NORTHWEST...POSSIBLY EVEN WESTWARD...IN 24 TO 36 HOURS.  THE
AVN MODEL QUICKLY MOVES A SHORTWAVE TROUGH OFF THE CAROLINAS IN 24
TO 48 HOURS...WHICH CREATES A WEAKNESS IN THE STRONG SUBTROPICAL
RIDGE CURRENTLY LOCATED TO THE NORTH OF OLGA.  THIS ALLOWS THE
CYCLONE TO MOVE SLOWLY NORTHWARD BEFORE THE SHORTWAVE LIFTS OUT AND
THE RIDGE BUILDS BACK IN...PUSHING OLGA BACK TO THE WEST OR EVEN TO
THE SOUTHWEST.  THE UKMET AND NOGAPS MODELS ARE LESS AGGRESSIVE WITH
THE AMPLITUDE OF THE SHORTWAVE TROUGH AND KEEP THE RIDGE TO THE
NORTH INTACT THROUGHOUT THE FORECAST PERIOD.  THE OFFICIAL FORECAST
TRACK IS A LITTLE TO THE RIGHT OF THE PREVIOUS TRACK AND CLOSE TO
THE AVN-UKMET-NOGAPS MODEL CONSENSUS.

AS THE AFOREMENTIONED VORTICITY CENTER DROPS SOUTHWARD...THE
UPPER-LEVEL SHEAR MAY DECREASE ENOUGH TO ALLOW FOR SOME ADDITIONAL
SLIGHT STRENGTHENING TONIGHT.  HOWEVER...ALL OF THE GLOBAL MODELS
AGREE THAT STRONG UPPER-LEVEL WESTERLY SHEAR WILL OVERSPREAD THE
BAHAMAS AND AFFECT OLGA IN 24 TO 36 HOURS...WHICH SHOULD BRING ABOUT
SIGNIFICANT WEAKENING IN THE LATTER FORECAST PERIODS.  HOWEVER...IF
OLGA TRACKS A LITTLE FARTHER NORTH OR NORTHWESTWARD THAN THE
OFFICIAL FORECAST IS INDICATING...THEN THE CYCLONE COULD MOVE UNDER
A 200 MB ANTICYCLONE EAST OF FLORIDA LIKE THE NEW 18Z AVN RUN IS
FORECASTING.  THIS WOULD CREATE A MORE FAVORABLE ENVIRONMENT FOR
STRENGTHENING...AND ALSO PROLONG THE ALREADY VERY LONG 2001 ATLANTIC
HURRICANE SEASON.

12-FT SEAS RADII WERE INCREASED IN ALL QUADRANTS BASED ON 13-FT SEA 
HEIGHTS REPORTED IN 21Z AND 00Z SHIP AND BUOY OBSERVATIONS. 
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     02/0300Z 23.6N  69.1W    35 KTS
12HR VT     02/1200Z 24.1N  69.6W    35 KTS
24HR VT     03/0000Z 24.7N  70.2W    35 KTS
36HR VT     03/1200Z 25.3N  70.8W    30 KTS
48HR VT     04/0000Z 26.0N  71.5W    25 KTS...DISSIPATING
72HR VT     05/0000Z 26.5N  73.0W    20 KTS...REMNANT LOW
 
 
NNNN