[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT42 KNHC 250255
TCDAT2

TROPICAL STORM PHILIPPE DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL172011
1100 PM AST SAT SEP 24 2011

A 2344 UTC ASCAT PASS OVER PHILIPPE INDICATES THE LOW-LEVEL CENTER
IS LOCATED VERY NEAR A RECENT BURST OF DEEP CONVECTION...BUT THAT
THE MAXIMUM WINDS ARE PROBABLY BARELY 35 KT.  SINCE THE CONVECTION
HAS BEEN ON A GENERAL UPWARD TREND OVER THE PAST COUPLE OF
HOURS...THE INITIAL INTENSITY IS HELD AT 35 KT.

PHILIPPE IS LOCATED ON THE SOUTHERN PERIPHERY OF A WEAK MID-LEVEL
RIDGE...AND THAT RIDGE IS EXPECTED TO SHIFT EASTWARD AND STRENGTHEN
NEAR THE AFRICAN COAST IN THE COMING DAYS AS A DEEP TROUGH DIGS
OVER THE CENTRAL ATLANTIC.  THEREFORE...THE MOTION OF THE
CYCLONE...WHICH IS CURRENTLY 295/10 KT...IS FORECAST TO TURN
NORTHWESTWARD AND SLOW DOWN AS PHILIPPE MOVES BETWEEN THESE TWO
SYNOPTIC FEATURES.  THERE IS VERY GOOD AGREEMENT AMONG THE MODELS
UNTIL ABOUT 72 HOURS...AFTER WHICH TIME THE GFS AND ECMWF SHOW A
SLOWER AND WESTWARD-LEANING MOTION WHILE THE BULK OF THE OTHER
MODELS INDICATE A TURN TOWARD THE NORTH AND NORTH-NORTHEAST.  A
SLOWER MOTION IS FAVORED SINCE THERE IS A LOT OF UNCERTAINTY...AND
THE OFFICIAL FORECAST ENDS UP CLOSE TO THE GFS BY DAY 5.

THE FORECAST TRACK OF PHILIPPE NEVER REALLY TAKES THE CYCLONE OVER
SIGNIFICANTLY WARMER WATERS...AND THE UNDERLYING OCEAN SHOULD
DEFINITELY BE COOLER AFTER ABOUT 48 HOURS.  IN ADDITION...PHILIPPE
SHOULD BE MOVING OUT OF AN ENVIRONMENT OF LIGHT UPPER-LEVEL WINDS
INTO AN AREA OF STRONGER SOUTHWESTERLY SHEAR IN ABOUT 3 DAYS.
THEREFORE...STRENGTHENING IS EXPECTED MAINLY DURING THE NEXT 48
HOURS WITH SOME WEAKENING POSSIBLE BY DAYS 4 AND 5.  THE OFFICIAL
FORECAST LIES GENERALLY CLOSE TO THE INTENSITY CONSENSUS AND SHOWS
PHILIPPE BECOMING A HURRICANE IN THE 48-72 HOUR TIME FRAME.

FORECAST POSITIONS AND MAX WINDS

INIT  25/0300Z 11.6N  28.8W   35 KT  40 MPH
 12H  25/1200Z 12.1N  30.5W   40 KT  45 MPH
 24H  26/0000Z 13.1N  32.5W   50 KT  60 MPH
 36H  26/1200Z 14.1N  34.1W   55 KT  65 MPH
 48H  27/0000Z 15.4N  35.3W   65 KT  75 MPH
 72H  28/0000Z 18.0N  37.0W   65 KT  75 MPH
 96H  29/0000Z 21.0N  38.0W   60 KT  70 MPH
120H  30/0000Z 24.0N  38.0W   60 KT  70 MPH

$$
FORECASTER BERG



This weather bulletin was brought to you by:
www.nashvilleweather.net