[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT42 KNHC 290256
TCDAT2

TROPICAL STORM PHILIPPE DISCUSSION NUMBER  20
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL172011
1100 PM AST WED SEP 28 2011

PHILIPPE REMAINS A SHEARED TROPICAL CYCLONE...HOWEVER DEEP
CONVECTION HAS DEVELOPED AND PERSISTED CLOSER TO THE LOW-LEVEL
CENTER DURING THE PAST SEVERAL HOURS.  SATELLITE ESTIMATES FROM
TAFB AND SAB SUPPORT AN INTENSITY OF 40 KT...AND THIS COULD BE A
LITTLE CONSERVATIVE. THE UPPER-WIND PATTERN AHEAD OF PHILIPPE
APPEARS TO BE A LITTLE MORE CONDUCIVE FOR STRENGTHENING DURING THE
NEXT DAY OR SO.  AN UPPER-LEVEL TROUGH TO THE WEST OF THE CYCLONE
IS FORECAST TO CUT-OFF AND MOVE SOUTHWESTWARD.  THIS SHOULD RESULT
IN A REDUCTION OF THE SHEAR AND THE UPDATED NHC INTENSITY FORECAST
NOW CALLS FOR SOME MODEST INCREASE IN INTENSITY DURING THE NEXT
24-36 HOURS. THIS IS IN GOOD AGREEMENT WITH THE SHIPS/LGEM
GUIDANCE.  IN 2 TO 3 DAYS PHILIPPE IS FORECAST TO MOVE NEAR THE
EASTERN SIDE OF AN UPPER-LEVEL RIDGE...IN AN AREA OF STRONG
NORTHERLY WINDS ASSOCIATED WITH THE OUTFLOW FROM OPHELIA.  THIS
SHOULD CAUSE PHILIPPE TO QUICKLY WEAKEN AND BECOME A REMNANT LOW IN
ABOUT 4 DAYS.

THE TRACK FORECAST REASONING REMAINS UNCHANGED AND THE GUIDANCE
REMAINS IN FAIRLY GOOD AGREEMENT DURING THE FIRST 2-3 DAYS.
PHILIPPE SHOULD CONTINUE ON A WEST-NORTHWEST TO NORTHWEST MOTION
AROUND THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL RIDGE OVER THE
EASTERN ATLANTIC.  AFTER 72 HOURS...THE CYCLONE IS FORECAST TO TURN
WESTWARD AS A STRONG DEEP-LAYER RIDGE BUILDS OVER THE NORTH-CENTRAL
ATLANTIC.  THE OFFICIAL FORECAST HAS BEEN ADJUSTED A LITTLE
WESTWARD DURING THE FIRST 72 HOURS...AND IS A LITTLE SOUTH OF THE
PREVIOUS TRACK THEREAFTER.  THE NHC TRACK IS NEAR THE MIDDLE OF THE
GUIDANCE ENVELOPE.


FORECAST POSITIONS AND MAX WINDS

INIT  29/0300Z 17.4N  40.8W   40 KT  45 MPH
 12H  29/1200Z 18.3N  42.1W   45 KT  50 MPH
 24H  30/0000Z 19.8N  43.8W   50 KT  60 MPH
 36H  30/1200Z 21.2N  45.6W   50 KT  60 MPH
 48H  01/0000Z 22.2N  47.3W   45 KT  50 MPH
 72H  02/0000Z 23.8N  50.9W   35 KT  40 MPH
 96H  03/0000Z 24.5N  55.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  04/0000Z 24.5N  59.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
FORECASTER BROWN



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