Super Typhoon Parma - Forecasting Cat 5, Luzon under the gun
Posted by JAC on 10/1/2009, 9:15 am














WDPN33 PGTW 010300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 19W (PARMA)WARNING NR 14//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. SUPER TYPHOON (STY) 19W (PARMA) HAS RAPIDLY INTENSIFIED AND
HAS DEVELOPED A PIN-HOLE EYE. ANIMATED WATER VAPOR IMAGERY SHOWS THE
SYSTEM HAS SIGNIFICANTLY DEEPENED WITH MULTIPLE CONVECTIVE BANDS
WRAPPING TIGHTER INTO THE WELL-DEFINED EYE. THE SYSTEM IS EXHIBITING
EXCELLENT POLEWARD OUTFLOW INTO A TROPICAL UPPER TROPOSPHERIC TROUGH
TO THE NORTH. CURRENT INTENSITY AND POSITION ARE BASED ON DVORAK
INTENSITY FIXES FROM PGTW AND RJTD WITH HIGH CONFIDENCE. UPPER LEVEL
ANALYSIS INDICATES THE SYSTEM IS SOUTH OF THE RIDGE AXIS WITH A
DIVERGENT POINT SOURCE DIRECTLY OVERHEAD. TY 19W IS TRACKING ALONG
THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL SUBTROPICAL RIDGE TO THE
NORTHEAST IN A REGION OF LOW TO MODERATE VERTICAL WIND SHEAR.
3. FORECAST REASONING
   A. THE FORECAST REASONING HAS NOT CHANGED SINCE THE LAST
PROGNOSTIC REASONING BULLETIN.
   B.  TY 19W IS EXPECTED TO CONTINUE ALONG THE TRACK DESCRIBED IN
PARA 2.A. THE ENVIRONMENTAL CONDITIONS WILL REMAIN FAVORABLE FOR
CONTINUED INTENSIFICATION UP TO TAU 48, WHICH WILL BE FURTHER ENHANCED
BY INCREASING ALONG-TRACK SEA SURFACE TEMPERATURES. BY TAU 72, LAND
INTERACTION WITH THE ISLAND OF LUZON WILL DIMINISH SOME OF ITS
INTENSITY BUT THE SYSTEM WILL OTHERWISE REMAIN A STRONG TYPHOON.
   C. AFTER TAU 72, STY PARMA WILL WEAKEN SLIGHTLY AS IT CONTINUES TO
INTERACT WITH NORTHEASTERN LUZON'S TOPOGRAPHY. ONCE IT CROSSES INTO
LUZON STRAIT, IT WILL REGAIN/MAINTAIN ITS STRONG TYPHOON INTENSITY.
DURING THIS PERIOD, TYPHOON PARMA WILL SLOW DOWN ITS FORWARD MOTION AS
A BREAK IN THE STEERING RIDGE DEVELOPS AND POSSIBLE INTERACTION WITH
TYPHOON 20W (MELOR) COMMENCES. AVAILABLE NUMERIC TRACK GUIDANCE ARE IN
FAIR AGREEMENT UP TO TAU 48 WHERE THEY PROGRESSIVELY DIVERGE WITH
JGSM, GFS AND TCLAPS TO THE EXTREME RIGHT AND NOGAPS, GFDN, WBAR, AND
EGRR TO THE FAR LEFT. THIS TRACK FORECAST IS JUST TO THE LEFT OF THE
MIDDLE OF THE ENVELOPE AND RIGHT OF CONSENSUS AND ECMWF.//
NNNN

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Super Typhoon Parma - Forecasting Cat 5, Luzon under the gun - JAC, 10/1/2009, 9:15 am
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