WDPN31 PGTW 051500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 31W (KALMAEGI) WARNING NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.5N 115.9E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 323 NM WEST-SOUTHWEST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 19 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON
(TY) 31W (KALMAEGI) WITH STRONG RADIAL OUTFLOW HAVING CONSOLIDATED
OVER THE PAST 6 HOURS WITH CONTINOUS DEEP CONVECTION. DESPITE
MULTIPLE ATTEMPTS THE SYSTEM HAS BEEN UNABLE TO MAINTAIN AN EYE
FEATURE. THE ENVIRONMENT CONTINUES TO BE FAVORABLE FOR FURTHER
DEVELOPMENT WITH WARM SEA SURFACE TEMPERATURES (28 C TO 29 C) AND
RELATIVELY LOW VERTICAL WIND SHEAR (10--15 KTS). THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON EIR IMAGERY AND
AGENCY FIXES.  THE INITIAL INTENSITY OF 90 KTS IS ASSESSED WITH
HIGH CONFIDENCE BASED ON OBJECTIVE AID ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTHWEST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T5.0 - 90 KTS
   DEMS: T5.0 - 90 KTS
   CIMSS ADT: 82 KTS AT 051130Z
   CIMSS AIDT: 78 KTS AT 051130Z
   CIMSS D-MINT: 77 KTS AT 050948Z
   CIMSS D-PRINT: 81 KTS AT 051230Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY KALMAEGI WILL REMAIN ON A NORTHWESTWARD
TRACK FOR THE REMAINDER OF THE FORECAST PERIOD DRIVEN BY THE
SUBTROPICAL RIDGING TO THE NORTH. THE SYSTEM WILL CONTINUE TO BUILD
STRENGTH AS IT TRAVERSES WARM WATERS WITH LITTLE VERTICAL WIND
SHEAR TO OPPOSE IT. TY KALMAEGI WILL BEGIN WEAKENING BY TAU 24
FOLLOWED BY LANDFALL SOUTH OF TAM QUAN, VIETNAM BETWEEN TAU 24 AND
TAU 36. THE SYSTEM WILL FULLY DISSIPATE OVER LAND BY TAU 48.

MODEL DISCUSSION: MODEL GUIDANCE IS IN GOOD AGREEMENT WITH A
CROSS-TRACK SPREAD OF 70 NM THROUGH TAU 36. NAVGEM REMAINS THE MAIN
OUTLIER, PICTURING A TRACK SLIGHTLY NORTH OF THE OTHER CONSENSUS
MEMBERS. THE JTWC FORECASTED TRACK LIES CLOSE TO THE MULTI-MODEL
CONSENSUS WITH HIGH CONFIDENCE. FORECASTED INTENSITY GUIDANCE HAS A
SPREAD OF AROUND 15 KTS. THE JTWC OFFICIAL FORECAST REFLECTS
INTENSITIES IN LINE WITH THE MULTI-MODEL CONSENSUS WITH HIGH
CONFIDENCE. 

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