WDPN31 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (MAWAR) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 6.1N 149.2E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 61 NM SOUTH OF PULUWAT
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTION CONSOLIDATING AROUND A FULLY OBSCURED LOW LEVEL
CIRCULATION CENTER (LLCC). A RECENT 201751Z GMI 37GHZ IMAGE
INDICATES A FALSE MICROWAVE EYE. THE INITIAL POSITION IS JUST SOUTH
AWAY FROM THE MAIN UPDRAFT BURST AND IS PLACED WITH HIGH
CONFIDENCE. THE INITIAL INTENSITY HAS INCREASED QUICKLY AND IN LINE
WITH THE RAPID INTENSIFICATION (RI) PREVIOUSLY MENTIONED IN THE
LAST FORECAST. THE INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED
UPON MULTIPLE DVORAK AGENCY ESTIMATES ALONG WITH MULTIPLE OBJECTIVE
DVORAK ESTIMATES FROM ADVANCED DVORAK TECHNIQUE (49KTS), OPEN AIIR
(58KTS), AND DEEP MICRONET (47KTS). THE POLEWARD CHANNEL HAS
DIRECTLY OPENED, HELPING THE OUTFLOW RELEASE THE EXCESS MASS FOR
THE NASCENT SYSTEM. THE ENVIRONMENT REMAINS RIPE FOR TS MAWAR TO
THRIVE AND DEVELOP, WITH WARM (29-30C) SEA SURFACE TEMPERATURES,
LOW TO MODERATE VERTICAL WIND SHEAR (VWS), AND ROBUST POLEWARD AND
MODERATE WESTWARD OUTFLOW ALOFT.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: NEAR EQUATORIAL RIDGE (NER) TO THE EAST
AND SUBTROPICAL RIDGE (STR) TO THE NORTHWEST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 39 KTS AT 201600Z
   CIMSS ADT: 49 KTS AT 201730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: STRONG POLEWARD AND MODERATE WESTWARD OUTFLOW

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: TS 02W (MAWAR) WILL CONTINUE TO CONSOLIDATE AS
IT PROGRESSES ON A NORTH-NORTHWEST TRACK TOWARDS THE MARIANA
ISLANDS, UNDER THE STEERING INFLUENCE OF THE NER TO THE EAST AND
STR TO THE NORTHWEST. THE FAVORABLE ENVIRONMENT CHARACTERIZED BY
LOW TO MODERATE VERTICAL WIND SHEAR AND WARM SEA SURFACE
TEMPERATURES (30-31C), AND STRONG OUTFLOW ALOFT WILL CONTINUE TO
DEVELOP THE SYSTEM TO TYPHOON STRENGTH BY TAU 24. OVER THE NEXT 24
HOURS, MAWAR CONTINUES TO SHOW POTENTIAL OF DEVELOPING MORE RAPIDLY
AS THE POLEWARD OUTFLOW CONTINUES TO MATURE NEAR THE CORE
CONVECTION AND THE VERTICAL WIND SHEAR BEGINS TO RELAX. AFTER TAU
24, 02W WILL CONTINUE TRACKING NORTH-NORTHWESTWARD AND INTENSIFY AT
A MORE NATURAL RATE UNTIL REACHING 90KTS BY TAU 72 JUST TO THE
SOUTHEAST OF GUAM. THE SYSTEM NOW APPEARS TO PASS JUST ALONG THE
NORTHERN EDGE OF GUAM AND BETWEEN ROTA, DUE TO THE BUILDING OF THE
NER TO THE EAST. THIS IS A SLIGHT SHIFT FROM THE PREVIOUS FORECAST
POSITIONS. THIS SHIFT WILL HAVE TWO PRIMARY IMPACTS ON 02W, THE
FIRST WILL BEGIN TO GUIDE THE SYSTEM WEST-NORTHWESTWARD THROUGH THE
FORECAST PERIOD, AND SECOND, IT WILL NEGATIVELY IMPACT THE ROBUST
POLEWARD OUTFLOW CHANNEL. THE LARGE REDUCTION IN POLEWARD OUTFLOW,
COUPLED WITH COOLING SSTS, WILL BEGIN ONLY ALLOW A SLOWER
INTENSIFICATION TREND. BY TAU 120 AND BEYOND, THE SYSTEM WILL
CONTINUE TRACKING WEST-NORTHWESTWARD AT A PEAK INTENSITY NEAR
105KTS.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN MUCH TIGHTER AGREEMENT
THAN THE PREVIOUS 6 HOURS, WITH AFUM REMAINING THE FAR-LEFT OUTLIER
AND NAVGEM THE FAR-RIGHT SPREAD TO 165NM. EXCLUDING AFUM AND
NAVGEM, THE BULK OF THE MODEL GUIDANCE INDICATES ONLY A 90NM SPREAD
THROUGH TAU 72, WHICH GENERALLY FOLLOWS THE JTWC FORECAST TRACK
LAID JUST EAST OF GUAM. FURTHERMORE, THE ECMWF ENSEMBLE AND JGSM
ARE THE PRIMARY MEMBERS THAT BRING THE SYSTEM JUST SLIGHTLY TO THE
WEST OF GUAM. THE JTWC FORECAST TRACK IS PLACED NEAR THE
MULTI-MODEL CONSENSUS WITH OVERALL HIGH CONFIDENCE IN THE FIRST 72
HOURS. THEREAFTER, CONFIDENCE SLIGHTLY WANES TO MEDIUM, AS THE
MODEL SPREAD GRADUALLY INCREASES AFTER GUAM, BASED UPON THE HIGHER
MODEL SPREAD. RELIABLE MODEL INTENSITY GUIDANCE IS IN GOOD
AGREEMENT WITH ALL MEMBERS AS WELL AS SEVERAL RAPID INTENSIFICATION
(RI) AIDS SHOWING A MODERATE INCREASE IN INTENSITY THROUGH TAU 72
AND A MORE GRADUAL INCREASE AFTER TAU 72 AND THROUGH THE FORECAST
PERIOD. FOR THIS REASON, THE JTWC FORECAST INTENSITY IS PLACED WITH
OVERALL MEDIUM CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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