WDPN32 PGTW 030300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (MAYSAK) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.3N 110.1E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 130 NM NORTHEAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: WESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A SLOWLY
CONSOLIDATING SYSTEM, WITH AN IRREGULAR CDO FEATURE OVERLAYING AN
OBSCURED LOW LEVEL CIRCULATION CENTER. A 022258Z WSF-M MICROWAVE
REVEALED AN ILL-DEFINED LLCC AND AN UPPER-LEVEL MICROWAVE EYE
FEATURE, DISPLACED TO THE SOUTH OF THE LLCC DUE TO THE PERSISTENT
NORTH-NORTHEASTERLY SHEAR. ANIMATED RADAR DATA DEPICTS A
CONSOLIDATED LLCC DRIFTING SLOWLY NORTHWESTWARD. THE INITIAL
POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE RADAR AND
MICROWAVE IMAGERY NOTED ABOVE. THE INITIAL INTENSITY IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON A BLEND OF THE SUBJECTIVE AND
OBJECTIVE INTENSITY ESTIMATES NOTED BELOW. ENVIRONMENTAL CONDITIONS
ARE MARGINAL, WITH WARM SSTS, LOW OHC, MODERATE NORTHEASTERLY SHEAR
AND MODERATE EQUATORWARD OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T2.5 - 35 KTS
   CIMSS SATCON: 38 KTS AT 030100Z
   CIMSS ADT: 45 KTS AT 030130Z
   CIMSS AIDT: 37 KTS AT 030130Z
   CIMSS D-MINT: 33 KTS AT 022314Z
   CIMSS D-PRINT: 32 KTS AT 030000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL STORM (TS) 10W (MAYSAK) CONTINUES
DRIFTING SLOWLY NORTHWESTWARD ALONG THE WEAK SOUTHWESTERN FLANK OF
A STR FAR TO THE NORTHEAST. THE SYSTEM IS FORECAST TO MAKE LANDFALL
ALONG THE SOUTHERN COAST OF HAINAN ISLAND, NEAR SANYA, WITHIN THE
NEXT 12 HOURS. SUBSEQUENT TO LANDFALL, THE SYSTEM WILL SKIRT THE
WESTERN COAST OF HAINAN AND MOVE INTO THE GULF OF TONKIN BY TAU 24,
THEN BEGIN TO RECURVE AROUND THE SOUTHWESTERN SIDE OF THE STR AND
TURN NORTHWARD. A SECOND LANDFALL IN THE VICINITY OF HAIPHONG,
VIETNAM IS FORECAST TO OCCUR BETWEEN TAU 36 AND 48. THE SYSTEM WILL
THEN TRACK NORTHWARD INTO SOUTHERN CHINA THROUGH THE END OF THE
FORECAST. TS 10W CONTINUES TO SLOWLY INTENSIFY AS DEEP CONVECTION
HAS PERSISTED OVER AND AROUND THE LLCC FOR THE LAST 12 HOURS.
PROXIMITY TO LAND AND THE SHORT WINDOW REMAINING OVER WATER WILL
INHIBIT SIGNIFICANT ADDITIONAL INTENSIFICATION PRIOR TO LANDFALL.
THE SYSTEM WILL LIKELY WEAKEN BELOW 35 KNOTS AS IT TRACKS ALONG THE
WESTERN COAST OF HAINAN BUT THEN QUICKLY REGAIN 35 KNOT INTENSITY
BY TAU 24. A SMALL WINDOW OF OPPORTUNITY FOR ADDITIONAL
INTENSIFICATION EXISTS FROM TAU 24 TO TAU 36 AS THE SYSTEM MOVES
OVER THE VERY WARM GULF OF TONKIN AND MOVES INTO A REGION OF
RELATIVELY LOWER SHEAR, AND IS FORECAST TO REACH 40-45 KNOTS BEFORE
MAKING THE SECOND LANDFALL. AFTER MOVING ASHORE, THE SYSTEM WILL
RAPIDLY DISSIPATE DUE TO TERRAIN INTERACTION. 

MODEL DISCUSSION: TRACK GUIDANCE IS SOMEWHAT SPLIT, WITH THE
DETERMINISTIC TRACKERS MOVING THE SYSTEM NORTH OR NORTHEAST THROUGH
TAU 12, THEN TRACKING UP THE CENTRAL PORTION OF HAINAN BEFORE
RESUMING A NORTHWESTWARD TRACK THROUGH THE REMAINDER OF THE
FORECAST. THE ARTIFICIAL INTELLIGENCE MODELS ON THE OTHER HAND
TRACK THE SYSTEM NORTHWEST ALONG THE WESTERN SIDE OF HAINAN, THEN
DEPICT A RECURVE INTO SOUTHERN CHINA. THE JTWC FORECAST IS PLACED
NEAR THE EXPERIMENTAL GDM FGNI TRACKER THROUGH THE FORECAST PERIOD,
WITH MEDIUM CONFIDENCE. INTENSITY GUIDANCE IS IN GOOD AGREEMENT
THAT THE SYSTEM WILL MAINTAIN ITS CURRENT INTENSITY OR INTENSIFY
SLIGHTLY PRIOR TO LANDFALL, THEN WEAKEN SLIGHTLY OVERLAND, BEFORE
RESUMING INTENSIFICATION THROUGH TAU 36, FOLLOWED BY RAPID
DISSIPATION OVER LAND. THE JTWC FORECAST IS POSITIONED CLOSE TO THE
FGNI AND HAFS-A GUIDANCE, WITH HIGH CONFIDENCE. 

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