Tropical Storm OLAF

ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM OLAF DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 PM PDT FRI OCT 03 2003
 
IN SPITE OF DVORAK INTENSITY ESTIMATES OF 25 KT FROM AFWA AND 30 KT
FROM TAFB AND SAB...A SHIP WITH A GOOD HISTORY REPORTED 45 KT WINDS
CLOSE TO THE CENTER OF THE TROPICAL CYCLONE.  SINCE THAT TIME THE
DEEP CONVECTION HAS BEEN PULLED A LITTLE FARTHER AWAY FROM THE
EXPOSED CENTER AND SO THE ADVISORY INTENSITY WINDS ARE ONLY RAISED
TO 40 KT...STILL WELL ABOVE THE SATELLITE ESTIMATES.

A QUIKSCAT PASS ALONG WITH MORE VISIBLE IMAGERY HAS NECESSITATED A
RELOCATION OF THE CENTER TO THE NORTH OF THE PREVIOUS TRACK.  THE
INITIAL MOTION IS NOW ESTIMATED TO BE 310/6.  SOME FAIRLY LARGE
ADJUSTMENTS HAVE ALSO BEEN MADE TO THE FORECAST TRACK.  THE
GFS...GFDL...AND NOGAPS TAKE OLAF SLOWLY NORTHWARD TOWARD THE
MEXICAN COAST OVER THE NEXT 24 HOURS...AND THEN BEND THE TRACK TO
THE NORTHWEST AT VARIOUS RATES AS OLAF ENCOUNTERS A WEAK MID-LEVEL
HIGH OVER MEXICO.  THERE IS A LOT OF SOUTHWESTERLY LOW-LEVEL FLOW
BEHIND TROPICAL STORM NORA THAT COULD PUSH OLAF NORTHWARD.  ON THE
OTHER HAND...WITH ALL THE DEEP CONVECTION TO THE SOUTH AND WEST OF
THE CENTER DUE TO THE PREVAILING SHEAR...THE STORM-SCALE FORCING
WOULD TEND TO DRAG THE CENTER MORE TO THE WEST.  THE OFFICIAL
FORECAST IS ADJUSTED TO THE RIGHT OF THE PREVIOUS ADVISORY...BUT
NOT AS FAR AS THE GFS/GFDL/NOGAPS GUIDANCE.  OLAF COULD MOVE CLOSER
TO THE COAST THAN FORECAST...BUT MY FEELING IS THAT IT WOULD HAVE
TO DO SO AS A WEAK AND SHEARED SYSTEM.

BOTH THE SHIPS AND GFDL GUIDANCE TAKE OLAF TO HURRICANE STRENGTH
WITHIN 36-48 HOURS.  GIVEN THE SHEAR...I FIND THAT OUTCOME HARD TO
ACCEPT.  THE OFFICIAL FORECAST SHOWS STRENGTHENING...BUT ONLY AFTER
36 HOURS WHEN THE NORTHEASTERLY SHEAR IS FORECAST TO ABATE.
 
FORECASTER FRANKLIN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      03/2100Z 12.7N  99.6W    40 KT
 12HR VT     04/0600Z 13.2N 100.0W    40 KT
 24HR VT     04/1800Z 14.0N 100.5W    40 KT
 36HR VT     05/0600Z 14.7N 101.0W    40 KT
 48HR VT     05/1800Z 15.3N 101.6W    45 KT
 72HR VT     06/1800Z 15.9N 102.5W    50 KT
 96HR VT     07/1800Z 16.5N 103.5W    55 KT
120HR VT     08/1800Z 17.0N 104.5W    60 KT
 
 
NNNN