WDPN32 PGTW 062100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 19W (NINETEEN) WARNING 
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.3N 137.4E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 860 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TS 19W HAS MAINTAINED A CENTRAL DENSE OVERCAST WITH A COMPACT CORE
OF INTENSE DEEP CONVECTION OBSCURING THE LOW-LEVEL CIRCULATION
CENTER (LLCC) AS INDICATED IN ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY. A FORTUITOUS 061658Z AMSR2 89GHZ IMAGE REVEALS
TIGHTLY-CURVED DEEP CONVECTIVE BANDING WRAPPING INTO A SMALL
MICROWAVE EYE FEATURE, WHICH SUPPORTS THE INITIAL POSITION WITH
HIGH CONFIDENCE, AND ALSO PROVIDES SOLID EVIDENCE THAT THE SYSTEM
IS CONSOLIDATING QUICKLY. THUS THE INITIAL INTENSITY HAS BEEN
INCREASED TO 45 KTS, CONSISTENT WITH A MICROWAVE EYE FEATURE, AND
IS ASSESSED WITH HIGH CONFIDENCE. ALTHOUGH LIMITED IN EXTENT, THE
SYSTEM HAS MAINTAINED RADIAL OUTFLOW AND LOW VERTICAL WIND SHEAR.
WARM SEA SURFACE TEMPERATURES AND HIGH OCEAN HEAT CONTENT VALUES
HAVE ALSO CONTRIBUTED TO THE RAPID CONSOLIDATION.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 34 KTS AT 061740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: HIGH OCEAN HEAT CONTENT VALUES.

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: DUE TO RAPID CONSOLIDATION, THE
INTENSITY FORECAST HAS BEEN REVISED WITH MORE SIGNIFICANT
INTENSIFICATION THROUGH THE FORECAST PERIOD AND A HIGHER PEAK
INTENSITY.

FORECAST DISCUSSION: TS 19W HAS CLEARLY CONSOLIDATED WITH A MARKED
IMPROVEMENT IN CONVECTIVE STRUCTURE. ADDITIONALLY, RAPID
INTENSIFICATION AIDS HAVE TRIGGERED SUPPORTING THE INCREASE IN THE
FORECAST INTENSITIES THROUGH TAU 72. THE SYSTEM IS NOW EXPECTED TO
INTENSIFY TO 85 KNOTS BY TAU 48 THEN 95 KNOTS BY TAU 72, A SLIGHTLY
LESS THAN CLIMATOLOGICAL RATE DUE TO THE LACK OF A CYAN RING (RAPID
INTENSIFICATION SIGNAL) IN 36GHZ IMAGERY AND THE LACK OF DISTINCT
OUTFLOW CHANNELS. TS 19W SHOULD TURN WESTWARD THROUGH TAU 48 UNDER
THE STEERING INFLUENCE OF THE STR TO THE NORTH THEN MORE
WEST-NORTHWESWARD AS IT TRACKS ALONG THE SOUTHWEST PERIPHERY OF THE
STR THROUGH TAU 120. UPPER-LEVEL FLOW IS EXPECTED TO REMAIN ZONAL
OVER THE EAST CHINA SEA WITH NO DEEP MIDLATITUDE SHORTWAVE TROUGHS
EXPECTED TO WEAKEN THE SUBTROPICAL STEERING RIDGE OR BOOST POLEWARD
OUTFLOW THUS THE INTENSIFICATION FORECAST IS CONSERVATIVE IN THE
LATER TAUS WITH A MODEST INCREASE TO 105 KNOTS BY TAU 96 THEN
WEAKENING AS THE SYSTEM INTERACTS WITH TAIWAN. 

MODEL DISCUSSION: OVERALL CONFIDENCE IN THE JTWC TRACK FORECAST IS
MEDIUM WITH A 125NM SPREAD IN MODEL SOLUTIONS AT TAU 72 DIVERGING
TO 250NM BY TAU 120. THERE IS ALSO MEDIUM CONFIDENCE IN THE JTWC
INTENSITY FORECAST DUE TO THE COMPACT NATURE OF THE SYSTEM AND A
WIDE SPREAD IN INTENSITY GUIDANCE THROUGH THE FORECAST PERIOD. THE
JTWC INTENSITY FORECAST IS SIGNIFICANTLY HIGHER THAN THE INTENSITY
CONSENSUS (ICNW) DUE TO THE VERY WEAK CONTRIBUTION FROM GFS, WHICH
INDICATES 25-35 KNOTS THROUGH THE FORECAST PERIOD. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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