WDPN31 PGTW 052100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 31W (KALMAEGI) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.2N 114.3E
   INITIAL INTENSITY: 100 KTS
   GEOGRAPHIC REFERENCE: 387 NM EAST-SOUTHEAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 18 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TYPHOON KALMAEGI REGATHERED ITSELF AFTER CROSSING THE SULU SEA AND
THE NORTHERN TIP OF PALAWAN AND IS RAMPING UP TOWARDS ITS PEAK
INTENSITY.  THE SYSTEM HAS DEVELOPED A RAGGED EYE AND IS ENTERING ITS
DIURNAL MAXIMUM PERIOD AND WILL BENEFIT FROM A BROAD AREA OF 
DIFFLUENT FLOW OVER THE WESTERN HEMISPHERE OF THE SYSTEM.  A DISTINCT 
EDGE OVER THE NORTHWEST QUADRANT ON THE UPSHEAR SIDE OF THE SYSTEM 
VERIFIES THAT THE SYSTEM IS
COCOONING ITSELF FROM THE EXTERNAL ENVIRONMENT AS IT CONTINUES
ALONG A STEADY WEST NORTHWESTERLY BEARING. AGENCY FIXES WERE ON TOP
OF EACH OTHER WITH THE RAGGED EYE MAKING PLACEMENT EASY BUT THE
DVORAKS RANGED FROM T5.0 THROUGH T6.0. THE INTENSITY ASSESSMENT
SITS IN THE MIDDLE AND ON TOP OF THE JTWC 5.5.
OBJECTIVE ASSESSMENTS HAVE BEEN LAGGING THE SUBJECTIVE DVORAKS BUT
THE DVORAKS ARE MATCH THE IMAGERY MUCH MORE CLOSELY.

INITIAL WIND RADII BASIS: A 051323Z ASCAT PASS HELPED ADJUST THE
35KT AND 50KT RADII OVER THE NORTHEAST AND SOUTHEAST QUADRANTS. 

CURRENT STEERING MECHANISM: TYPHOON KALMAEGI IS BEING STEERED BY
THE SUBROPICAL RIDGE, WHICH IS CENTERED IN A 591DM HGT CENTER JUST
WEST OF THE LUZON STRAIT. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T6.0 - 115 KTS
   DEMS: T5.0 - 90 KTS
   CIMSS SATCON: 74 KTS AT 051406Z
   CIMSS ADT: 63 KTS AT 051730Z
   CIMSS AIDT: 73 KTS AT 051730Z
   CIMSS D-PRINT: 87 KTS AT 051800Z

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

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TYPHOON KALMAEGI WILL REACH PEAK INTENSITY
OVER THE NEXT 18 HOURS AS IT TRACKS ALONG A STEADY WEST-NORTHWEST
BEARING IN A FAVORABLE ENVIRONMENT. THE EXTREME WESTERN EXTENT OF
THE SUBTROPICAL RIDGE WILL REMAIN STEADY AND STATIONARY, FORCING
THE SYSTEM TOWARDS A LANDFALL NEAR THE PHO QUONG AREA. GALE FORCE
WINDFIELDS WILL BE MORE EXPANSIVE ON THE POLEWARD SIDE OF THE
SYSTEM AND EXTEND AS FAR NORTH AS DA NANG. THE SYSTEM WILL TAPER
OFF SLIGHTLY DURING THE LAND APPROACH BUT WILL COME ASHORE AT LOW
TYPHOON STRENGTH. 

MODEL DISCUSSION: TRACK GUIDANCE IS TIGHT AND BOTH CROSS-TRACK AND
ALONG-TRACK SPREADS ARE MINIMAL.  THE JTWC FORECAST RIDES THE
MULTI-MODEL CONSENSUS WITH A SLIGHT POLEWARD HEDGE TOWARDS SOME OF
THE NEWER AI TRACKERS. INTENSITY GUIDANCE IS ALSO UNANIMOUS IN A
STEEP PLUNGE IN INTENSITY BEGINNING WITH THE FINAL APPROACH TO
SHORE, AND A STEEP AND RAPID DISSIPATION OVER LAOS.  

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