WDPN32 PGTW 160900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 25W (MAN-YI) WARNING NR 
030//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.2N 125.6E
   INITIAL INTENSITY: 140 KTS
   GEOGRAPHIC REFERENCE: 281 NM EAST-SOUTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 57 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A VERY
IMPRESSIVE SYSTEM, WITH A 15NM WIDE STADIUM EYE WITH MULTIPLE
MESOVORTICES PRESENT WITHIN THE EYE. ANIMATED ENHANCED INFRARED
(EIR) IMAGERY SHOWS A NEARLY SYMMETRICAL CENTRAL DENSE OVERCAST
(CDO) EXTENDING OUTWARD FOR APPROXIMATELY 85NM TO 100NM, WITH THE
COLDEST CLOUD TOPS AROUND -72C, OR ABOUT 3C WARMER THAN A FEW HOURS
AGO. THE EYE TEMPERATURE IS MEASURED AT +21C, SLIGHTLY COOLER THAN
WHEN AT ITS WARMEST (+25C) ABOUT THREE HOURS AGO. THE LAST
HIGH-RESOLUTION MICROWAVE PASS FROM 2119Z REVEALED A POSSIBLE
SECONDARY EYEWALL BEGINNING TO FORM, BUT THE SYSTEM HAS NOT SHOWN
ANY OVERT SIGN OF AN EYEWALL REPLACEMENT CYCLE (EWRC). REGARDLESS
OF THE DETAILS, STY 25W REMAINS AN EXTREMELY STRONG AND DANGEROUS
SYSTEM. AT ANALYSIS TIME, THE CENTER WAS LOCATED 95NM SOUTHEAST OF
VIGA AND 123NM EAST OF LEGAZPI CITY. THE INITIAL POSITION WAS
ASSESSED WITH HIGH CONFIDENCE BASED ON THE SUBJECTIVE FIX POSITIONS
ON THE 15NM EYE. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM
CONFIDENCE, ON THE HIGHER END OF THE AGENCY DVORAK CURRENT
INTENSITY ESTIMATES OF T7.0 (140 KNOTS) FROM PGTW AND RJTD.
OBJECTIVE ESTIMATES CONTINUE TO BE RUNNING TOO LOW AND WITHOUT ANY
RECENT WIND SPEED MEASUREMENTS, THERE IS NO WAY TO SAY WHAT THE
ACTUAL INTENSITY IS WITH HIGHER CONFIDENCE. THE SYSTEM IS IN A
FAVORABLE ENVIRONMENT, WITH LOW SHEAR, WARM SSTS, HIGH OHC AND GOOD
RADIAL OUTFLOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED NEAR 20N 140E. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   RJTD: T7.0 - 140 KTS 
   RCTP: T7.5 - 155 KTS
   KNES: T6.5 - 127 KTS
   CIMSS ADT: 132 KTS AT 160600Z
   CIMSS AIDT: 129 KTS AT 160600Z
   CIMSS D-PRINT: 134 KTS AT 160600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: STY 25W WILL CONTINUE TO TRACK NORTHWESTWARD
ALONG THE SOUTHWEST SIDE OF THE STEERING RIDGE FOR THE NEXT 36 TO
48 HOURS. LANDFALL ALONG THE NORTHEASTERN COAST OF CATANDUANES
ISLAND IS EXPECTED WITHIN THE NEXT FEW HOURS. THE SYSTEM WILL THEN
SKIRT JUST NORTH OF PALILLO ISLAND BEFORE MAKING A SECOND LANDFALL
BETWEEN DINGALAN AND BALER, ON THE EAST COAST OF LUZON. THE SYSTEM
WILL THEN CROSS LUZON, LIKELY TRACKING ALONG THE SOUTHERN EDGE OF
THE CORDILLERA CENTRAL RANGE, PASS JUST SOUTH OF BAGUIO, THEN
EMERGE BACK OVER WATER VIA THE LINGAYEN GULF. BY TAU 48, THE SYSTEM
WILL RUN HEAD-FIRST INTO A STRONG COLD SURGE EVENT, PRECIPITATED BY
A 1045MB HIGH THAT MOVES INTO MANCHURIA OVER THE NEXT COUPLE OF
DAYS, AND SLOW DOWN SIGNIFICANTLY. IN THE NEAR-TERM, THE SYSTEM
SHOWS NO SIGNS OF WEAKENING AND WILL LIKELY MAKE LANDFALL AT
CATANDUANES AS A 140 KNOT SUPER TYPHOON. AFTER PASSING THE ISLAND,
THE SYSTEM WILL SLOWLY WEAKEN DUE TO TERRAIN INTERACTIONS AND AS IT
PASSES OVER SLIGHTLY COOLER, LOWER OHC WATERS. STY 25W WILL STILL
BE A VERY STRONG TYPHOON WHEN IT MAKES ITS SECOND LANDFALL, BETWEEN
120-130 KNOTS. MOVEMENT ACROSS OR VERY NEAR TO THE VERY RUGGED
TERRAIN OF NORTHERN LUZON WILL TEAR UP THE VORTEX, AND COMBINED
WITH A MODEST INCREASE IN SOUTHEASTERLY SHEAR, WILL LEAD TO RAPID
WEAKENING THROUGH TAU 36. ONCE BACK OVER OPEN WATER, THE SYSTEM
SLOWLY WEAKENS THROUGH TAU 48 DUE TO INCREASING SHEAR. AFTER TAU
48, THE SYSTEM WILL FACE RAPIDLY INCREASING SOUTHWESTERLY SHEAR
WHICH WILL DECAPITATE THE VORTEX AND SMOTHER IT WITH DRY AIR,
MARKING THE BEGINNING OF RAPID WEAKENING. THE SYSTEM WILL TURN
SOUTHWESTWARD ALONG THE LOW-LEVEL FLOW LINES, WHILE CONTINUING TO
RAPIDLY WEAKENING WITH FULL DISSIPATION EXPECTED NO LATER TAU 120
AND POTENTIALLY AS EARLY AS TAU 96. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN VERY GOOD
AGREEMENT THROUGH TAU 72, WITH LITTLE IN THE WAY OF EITHER CROSS-
OR ALONG-TRACK SPREAD. THE JTWC FORECAST IS SET NEAR THE CONSENSUS
MEAN TO TAU 48, THEN SHIFTS SLIGHTLY TO THE NORTHERN EDGE OF THE
ENVELOPE, CLOSER TO THE ECMWF TRACKER, THROUGH TAU 72. CONFIDENCE
IS HIGH THROUGH THIS POINT OF THE FORECAST. AFTER TAU 72, THE
MODELS BEGIN TO DIVERGE SIGNIFICANTLY, WITH A LARGE VARIANCE IN HOW
LONG THEY HOLD ONTO THE VORTEX AND HOW QUICKLY IT MOVES SOUTHWARD.
THE ECMWF LOSES THE VORTEX BY TAU 96 TO THE EAST OF HAINAN WHILE
THE GFS MOVES THE REMNANT VORTEX INTO EASTERN THAILAND BY TAU 120.
THE JTWC FORECAST TRACKS THE CONSENSUS MEAN THROUGH TAU 120, WITH
LOW CONFIDENCE. INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT THE
SYSTEM WILL WEAKEN STEADILY THROUGH TAU 24, THEN RAPIDLY TO TAU 48
AND THE STEADILY THROUGH THE END OF THE FORECAST PERIOD. THE JTWC
FORECAST GENERALLY FOLLOWS THE CONSENSUS BUT DEVIATES 15 KNOTS
HIGHER AT TAU 24, WHERE THE CONSENSUS SHOWS A 105 KNOT INTENSITY. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: HIGH
   INTENSITY 72-120 HR: LOW//
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