WDPN32 PGTW 022100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 10W (MAYSAK) 
WARNING NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.4N 110.4E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 147 NM NORTHEAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
DURING THE OVERNIGHT HOURS, TROPICAL DEPRESSION (TD) 10W (MAYSAK)
EXHIBITED MULTIPLE VORTICES WRAPPING CYCLONICALLY AROUND A LARGER
CYCLONIC ROTATION SOUTH OF HAINAN. THE BEST TRACK POSITIONS SHIFTED
TO TRACKING THE CENTROID POSITION AND THUS THE TRACK IS SHOWN AS
SOUTHWESTWARD THROUGH 1200Z. FROM 1200Z TO 1800Z THE SYSTEM APPEARS
TO HAVE CONSOLIDATED INTO ONE DISCRETE VORTEX AGAIN, WITH DEEP
CONVECTION FORMING ALONG THE SOUTHERN FLANK DURING DIURNAL
CONVECTIVE MAX (DMAX) PERIOD. ANIMATED RADAR DATA SUPPORTS THIS
ASSESSMENT, WITH A MUCH CLEARER LOW LEVEL CIRCULATION CENTER (LLCC)
STARTING TO APPEAR ON TO THE SOUTHEAST OF HAINAN. WHILE THE
CONVECTION IS CURRENTLY SUPPORTING A MODEST AMOUNT OF POLEWARD
OUTFLOW WHICH IS PUSHING BACK AGAINST THE SHEAR, THIS IS LIKELY TO
BE SHORT-LIVED AND JUST LIKE 24 HOURS AGO, THE VORTEX WILL BECOME
EXPOSED ONCE AGAIN LATER TODAY AFTER SUNRISE. THE INITIAL POSITION
IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE RADAR DATA. THE
INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, HEAVILY
WEIGHTED TOWARDS THE SUBJECTIVE AGENCY FIX INTENSITY ESTIMATES.
ENVIRONMENTAL CONDITIONS ARE MARGINAL, WITH WARM SSTS, MODERATE
EQUATORWARD OUTFLOW AND STRONG NORTHEASTERLY VWS.

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

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP
SUBTROPICAL RIDGE (STR) CENTERED SOUTH OF KYUSHU. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS
   CIMSS SATCON: 37 KTS AT 021930Z
   CIMSS ADT: 35 KTS AT 021930Z
   CIMSS AIDT: 34 KTS AT 021930Z
   CIMSS D-MINT: 26 KTS AT 021803Z
   CIMSS D-PRINT: 27 KTS AT 021900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: DRY MID-LEVEL AIR DRAPED ACROSS THE NORTHEASTERN
QUADRANT OF THE CIRCULATION. 

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: AFTER A BRIEF PERIOD OF ERRATIC MOTION, TD 10W
HAS RESUMED A NORTHWESTWARD TRACK TOWARDS HAINAN, WITH A LANDFALL
NEAR SANYA, CHINA EXPECTED WITHIN THE NEXT 12 HOURS. THE SYSTEM
WILL THEN TRAVERSE THE WESTERN COAST OF HAINAN BEFORE MOVING INTO
THE MORE OPEN WATERS OF THE GULF OF TONKIN. A SECOND LANDFALL IS
FORECAST TO OCCUR BETWEEN TAU 36 AND TAU 48 NORTHEAST OF HAIPHONG,
VIETNAM. THE SYSTEM WILL THEN CONTINUE INLAND OVER SOUTHERN CHINA.
IN TERMS OF INTENSITY, THE SYSTEM APPEARS TO BE CONSOLIDATING A BIT
AND MODEL DATA SUGGEST THE SHEAR SHOULD LESSEN OVER THE NEXT 12 TO
24 HOURS. THIS WILL ALLOW FOR THE SYSTEM TO INTENSIFY SLIGHTLY AS
IT APPROACHES LANDFALL ON THE SOUTH COAST OF HAINAN. AS TD 10W
SKIRTS THE WESTERN COAST OF HAINAN, IT WILL LIKELY MAINTAIN ITS
INTENSITY, ESPECIALLY THE PERIPHERAL WIND FIELD, WHICH WILL EXPAND
DURING THIS TIMEFRAME. AS THE SYSTEM MOVES OVER THE VERY WARM, HIGH
OHC WATERS OF THE GULF OF TONKIN, IT WILL HAVE A NARROW WINDOW OF
OPPORTUNITY FOR ADDITIONAL INTENSIFICATION, FORECASTED TO REACH 40
KNOTS PRIOR TO THE SECOND LANDFALL. AS THE SYSTEM MOVES INLAND IT
WILL RAPIDLY DETERIORATE AND DISSIPATE AS A TROPICAL CYCLONE BY TAU
60. 

MODEL DISCUSSION: TRACK GUIDANCE IS IN MODEST AGREEMENT, THOUGH
CROSS-TRACK SPREAD REMAINS SIGNIFICANT, EVEN IN THE EARLY FORECAST
TAUS. AT TAU 12, THE GFS TRACKS THE VORTEX NORTHWARD, ATTEMPTING TO
ROUND THE EAST COAST OF HAINAN, OPENING UP A 100NM SPREAD BETWEEN
IT AND THE ECMWF-AIFS AND THE EXPERIMENTAL GDM FGNI, WHICH LIE ON
THE WESTERN COAST OF HAINAN. CROSS-TRACK SPREAD CONTINUES TO
INCREASE THROUGH THE FORECAST PERIOD, LENDING MEDIUM CONFIDENCE TO
THE JTWC FORECAST WHICH IS POSITIONED ON THE WESTERN EDGE OF THE
GUIDANCE PACKAGE AND CLOSE TO THE TWO AFOREMENTIONED TRACKERS.
INTENSITY GUIDANCE IS IN GOOD AGREEMENT, THOUGH THE MESOSCALE
MODELS DO INDICATE A SLIGHTLY HIGHER PEAK INTENSITY IN THE GULF OF
TONKIN. THE JTWC FORECAST IS PLACED NEAR THE GDM FGNI INTENSITY
GUIDANCE WITH MEDIUM CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM//
NNNN