OLAF #4 - DISCUSSION

[AussieMark]

000
WTPZ45 KNHC 040855
TCDEP5
TROPICAL STORM OLAF DISCUSSION NUMBER 4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT SAT OCT 04 2003

LATEST ENHANCED INFRARED IMAGERY AND AN EARLIER 0332Z SSMI PASS
DEPICT THAT THE LOW-LEVEL CIRCULATION CENTER HAS TUCKED IN BENEATH
THE NORTHEASTERN EDGE OF THE CONVECTION. IMAGERY ALSO REVEALS A
RAGGED BANDING FEATURE DEVELOPING OVER THE NORTHWEST QUADRANT.
DVORAK SATELLITE INTENSITY ESTIMATES ARE 45 KT FROM TAFB AND
SAB...35 KT FROM AFWA. THE INITIAL INTENSITY REMAINS AT 45 KT.

THE INITIAL MOTION IS 320/6. A WEAK MID LEVEL RIDGE OVER MEXICO
SHOULD PROVIDE A NORTHWEST MOTION THROUGH THE FORECAST PERIOD. GFDL
AND GFDN DEPICT A WEAKER RIDGE OVER MEXICO...PLACING THE TROPICAL
CYCLONE OVER THE COAST OF MEXICO BY DAY 3. THE UKMET 0000Z RUN
INITIALIZED THE SYSTEM BUT INDICATED EXCESSIVE INTERACTION WITH
TROPICAL STORM LARRY. NOGAPS AND THE GFS INDICATE A STRONGER
RIDGE...GFS REFLECTING THE STRONGEST OF THE TWO. BOTH ALSO SHOW THE
RIDGE BUILDING OVER THE WEST COAST OF MEXICO AROUND 48 HOURS.
THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS TRACK AND A BLEND
OF THE GFS...NOGAPS AND THE GFDL THROUGH 72.

BASED ON RECENT IMAGERY...THE SHEAR APPEARS TO BE LETTING UP. THE
SHIPS AND THE GFDL INTENSIFY THE TROPICAL CYCLONE TO HURRICANE
STRENGTH IN LESS THAN 36 HOURS. IN FACT...THE GFDL BRINGS THE
INTENSITY UP TO 105 KT IN 72 HOURS...WHILE THE SHIPS INCREASES IT
TO 77 KT. THE OFFICIAL FORECAST IS CLOSER TO THE SHIPS.

FORECASTER ROBERTS/AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL 04/0900Z 13.8N 100.5W 45 KT
12HR VT 04/1800Z 14.4N 100.9W 50 KT
24HR VT 05/0600Z 15.0N 101.4W 60 KT
36HR VT 05/1800Z 15.6N 101.9W 65 KT
48HR VT 06/0600Z 16.1N 102.4W 70 KT
72HR VT 07/0600Z 16.8N 103.3W 75 KT
96HR VT 08/0600Z 17.3N 104.2W 75 KT
120HR VT 09/0600Z 17.8N 105.5W 75 KT