WDPN32 PGTW 191500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 15W (PULASAN) 
WARNING NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.5N 122.0E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 49 NM SOUTH-SOUTHEAST OF SHANGHAI, CHINA
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS FRAGMENTED, 
PULSING CONVECTION AND WEAK EASTERLY OUTFLOW OVER THE EAST CHINA SEA 
ALONG THE NORTHERN PERIPHERY OF THE MONSOON DEPRESSION KNOWN AS TD 
15W. THE SYSTEM HAS MAINTAINED A BROAD CENTER, ACCORDING TO ANIMATED 
RADAR SCANS AND ANIMATED EIR IMAGERY SHOWING A BROAD CIRCULATION WITH 
MAXIMUM WINDS (25-30 KTS) DISPLACED OVER 100 NM NORTHEAST OF THE 
CENTER, ACCORDING TO A 191158Z PARTIAL ASCAT IMAGE AND VARIOUS SHIP 
OBSERVATIONS. THERE ARE MULTIPLE SHIP TRAILS OBSERVED ON A 191200Z 
HIMAWARI-9 PROXY VISIBLE SATELLITE IMAGE, CONSISTENT WITH LIGHT 
SYNOPTIC WINDS IN THE BROAD PRESSURE CENTER THAT WERE OBSERVED IN 
EARLIER SCATTEROMETRY IMAGES. THE DEEPEST CONVECTION IS SITUATED OVER 
A SHARP WAVE THAT EXTENDS NORTHEASTWARD FROM THE LOW PRESSURE CENTER. 
THE SYSTEM'S CENTER IS SUPPORTED BY CYCLONIC WINDS REPORTED BY FOUR 
OMNIDIRECTIONAL SURFACE OBSERVATIONS SURROUNDING THE ASSESSED 
POSITION, BUT THE HORIZONTAL EXPANSE AND POSSIBLE ELONGATION OF THE 
LOW PRESSURE CENTER OR TROUGH REMAINS UNKNOWN. HENCE, THE SYSTEM 
CONTINUES TO BE A CHALLENGE TO TRACK AND THE CURRENT POSITION IS 
PLACED WITH SIGNIFICANT UNCERTAINTIES RESULTING IN LOW CONFIDENCE. 
THERE CONTINUES TO BE AN ABSENCE OF A CLOUD SYSTEM CENTER OVER THE
SYSTEM'S CENTER POSITION, AND THE WINDS ASSOCIATED WITH THE SYSTEM
ARE BEING ENHANCED BY A TIGHT PRESSURE GRADIENT AGAINST A SHARP
SUBTROPICAL RIDGE TO THE EAST. THE INITIAL INTENSITY IS ANALYZED
WITH MEDIUM CONFIDENCE BASED ON A BLEND OF SHIP AND SYNOPTIC
OBSERVATIONS, THE PARTIAL SCATTEROMETRY PASS, AND THE OBJECTIVE AND
SUBJECTIVE INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: SHARP, DEEP-LAYERED SUBTROPICAL RIDGE
TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   DEMS: T2.0 - 30 KTS
   CIMSS SATCON: 42 KTS AT 191021Z
   CIMSS ADT: 39 KTS AT 191130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 5-10 KTS
   SST: 28-30 CELSIUS
   OUTFLOW: WEAK EASTWARD
   OTHER FACTORS: LAND INTERACTION

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

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

FORECAST DISCUSSION: THE SYSTEM'S PRESSURE CENTER IS EXPECTED TO
CONTINUE TRACKING INLAND OVER THE SHANGHAI AREA, WHERE IT WILL 
CONTINUE TO SLOW IN ITS FORWARD MOTION AND EFFECTIVELY STALL THROUGH 
TAU 24 UNTIL IT IS PICKED UP BY AN APPROACHING TROUGH FROM THE 
NORTHWEST. THE MAXIMUM LOW-LEVEL WIND FIELD IS EXPECTED TO REMAIN 
LARGELY OFFSHORE AND TEMPORARILY TREND DOWN IN INTENSITIES WHILE THE 
SYSTEM CENTER SITS OVER LAND. ONCE PICKED UP BY THE APPROACHING 
TROUGH, WHICH IS ASSOCIATED WITH A COMBINED 150-KT JET MAXIMUM AND 
TIGHT THERMAL GRADIENT, A FRONTAL ZONE WILL INTRODUCE BAROCLINICITY 
INTO THE CORE AFTER TAU 24. EXITING THE COAST OF MAINLAND CHINA AS A 
DEVELOPING STABLE WAVE, THE SYSTEM WILL ACCELERATE IN AN EAST-
NORTHEASTWARD TRACK, UNDERGOING THE BEGINNING STAGES OF EXTRATROPICAL 
TRANSITION AND FRONTOGENESIS. THE SYSTEM WILL ACQUIRE THE 
CHARACTERISTICS OF A SHANGHAI LOW AS EXTRATROPICAL TRANSITION 
CONTINUES THROUGH TAU 36 AND COMPLETES BY TAU 72. THE SYSTEM WILL 
TRACK THROUGH THE KOREA STRAIT, POSSIBLY MAKING LANDFALL NEAR JAPAN. 
THE LOCATION OF THE JETSTREAM OVER THE REPUBLIC OF KOREA WILL PREVENT 
THE SYSTEM FROM VENTURING NORTH; IF BY SLIM CHANCE IT DOES, IT CAN 
ONLY DO SO AS AN EXTRATROPICAL LOW.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE SHARES IMPROVING AGREEMENT 
THAT THE SYSTEM WILL SLOW OR STALL OVER LAND AND EVENTUALLY PIVOT TO 
AN ACCELERATING EAST-NORTHEASTWARD TRACK. MODEL GUIDANCE VARIES 
SLIGHTLY IN BOTH TRACK PLACEMENT AND TRACK SPEED IN THE LATER
TAUS, INCLUDING VARIATIONS WITHIN EACH MODEL FROM RUN-TO-RUN. THE
MORE RELIABLE GUIDANCE MAINTAINS SLOWER TRACK SPEEDS THAN THAT OF
THE CONSENSUS MEAN, WHICH IS WHERE THE JTWC FORECAST IS HEDGED. THE
INTENSITY GUIDANCE IS IN TIGHT AGREEMENT, SLOWLY TRENDING THE
SYSTEM INTENSITY DOWN. THE JTWC FORECAST IS ON THE HIGH SIDE OF THE
INTENSITY CONSENSUS DUE TO THE INCLUSION OF FORWARD TRACK SPEEDS
ALONG THE DEVELOPING FRONTAL ZONE AND TIGHTENING PRESSURE GRADIENT.
THE TRACK AND INTENSITY FORECASTS ARE PREDICTED WITH MEDIUM
CONFIDENCE AS A RESULT OF THE INITIAL POSITIONING UNCERTAINTY AND
LACK OF INTENSITY-RELATED DATA, AS WELL AS A REFLECTION OF THE
VARIATIONS BETWEEN MODEL RUNS.

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