WDPN31 PGTW 211500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (MAWAR) 
WARNING NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 8.0N 148.3E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 385 NM SOUTH-SOUTHEAST OF ANDERSEN AFB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
EXPANDING CENTRAL DENSE OVERCAST (CDO) FEATURE THAT IS FULLY
OBSCURING THE LLCC BENEATH. A RECENT 210821Z SSMIS 91GHZ MICROWAVE
IMAGE REVEALS IMPROVED CORE CONVECTION WITH A PARTIALLY EXPOSED
SOUTHERN SEMICIRCLE ALLOWING THE TIGHTLY WRAPPING LOW LEVEL CLOUD
LINES BELOW TO BE SEEN. WHILE EIR AND SSMIS IMAGERY IS HELPFUL,
THEY PALE IN COMPARISON TO A RECENT 210813Z RADARSAT-2 SYNTHETIC
APERTURE RADAR (SAR) PASS. THE SAR PASS INDICATED THAT THE LLCC IS
STILL SLIGHTLY E-W ELONGATED WITH THE BULK OF THE HIGHEST WINDS
(65-70KTS) EXISTING IN THE SOUTHERN SEMICIRCLE. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE FULLY
OBSCURED NATURE OF THE LLCC IN MSI AS WELL AS ITS ELONGATED
CIRCULATION AT 0813Z PROVIDED BY THE SAR PASS. THE INITIAL
INTENSITY OF 70KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON
SCALAR WIND DATA PROVIDED BY THE SAR PASS. IN THIS STAGE OF
TROPICAL CYCLONE DEVELOPMENT, AS SCENE TYPES CHANGE AND THE PATH IS
CLEARED FOR AND EYE TO FORM, THE SUBJECTIVE NATURE OF THE DVORAK
METHOD IS ON FULL DISPLAY. OUTLIERS IN FINAL INTENSITY ESTIMATE ARE
COMMON, HOWEVER THEIR VERACITY SHOULD BE CLOSELY EXAMINED.

INITIAL WIND RADII BASIS: SAR DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T4.0 - 65 KTS
   KNES: T4.5 - 77 KTS
   CIMSS ADT: 59 KTS AT 210830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: STRONG POLEWARD AND MODERATE WESTWARD OUTFLOW

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY 02W (MAWAR) HAS CONTINUED TO RAPIDLY
INTENSIFY OVER THE PAST SIX HOURS. AS THE SYSTEM CONTINUES TO PICK
UP SPEED UNDER THE STEERING INFLUENCE OF THE NER TO THE EAST, 02W
IS FORECAST TO MAINTAIN A GENERALLY NORTH-NORTHWESTWARD TRACK. THE
ENVIRONMENT SURROUNDING 02W IS FORECAST TO REMAIN FAVORABLE,
CHARACTERIZED BY WARM SSTS AND ROBUST OUTFLOW ALOFT BOTH POLEWARD
AND WESTWARD OVERWHELMING THE NEGATIVE EFFECTS OF LIMITED DRY AIR
ENTRAINMENT AND MODERATE MID-UPPER LEVEL VERTICAL WIND SHEAR (VWS).
HAVING RECENTLY ACHIEVED TYPHOON STRENGTH, THE SYSTEM WILL CONTINUE
TO DEVELOP OVER THE NEXT SEVERAL DAYS HOURS, FUELED BY THE
AFOREMENTIONED ROBUST OUTFLOW ALOFT AND WARM SSTS. NEAR TAU 72, THE
NER TO THE EAST REORIENTS AND BUILDS FURTHER NORTHEAST OF THE
SYSTEM, FORCING IT TO STEADY UP ON A GENERALLY WEST-NORTHWESTWARD
COURSE AFTER PASSING NORTH OF GUAM. BY TAU 120, NOW OVER THE WARM
WATERS AND DEEP OCEAN HEAT CONTENT (OHC) OF THE PHILIPPINE SEA, 02W
WILL REACH A PEAK INTENSITY OF 115KTS AS IT CONTINUES
WEST-NORTHWESTWARD.

MODEL DISCUSSION: WITH THE EXCEPTION OF AFUM AND NVGM, WHICH ARE
BOTH ONCE AGAIN THE OUTLIERS, NUMERICAL MODELS ARE IN GOOD
AGREEMENT WITH A MAXIMUM CROSS TRACK SPREAD OF 117NM BY TAU 72. THE
BULK OF THE GUIDANCE CONTINUES TO CARRY THE SYSTEM
NORTH-NORTHWESTWARD THROUGH 48 AFTER WHICH EVERY MEMBERS ALTERS
COURSE TO THE WEST-NORTHWEST THROUGH THE FORECAST PERIOD. AFTER TAU
72, ALONG TRACK SPREADING DOES INCREASE SLIGHTLY THROUGH THE
REMAINING FORECAST PERIOD. FOR THIS REASON THE JTWC FORECAST TRACK
IS PLACED INITIALLY WITH HIGH CONFIDENCE AND EVENTUALLY WITH MEDIUM
CONFIDENCE. RELIABLE MODEL INTENSITY GUIDANCE IS IN FAIR AGREEMENT
WITH SEVERAL MEMBERS AS WELL AS RAPID INTENSIFICATION (RI) AIDS
INDICATING ROBUST AND PERSISTENT INTENSIFICATION THROUGH TAU 60. AS
02W ENTERS THE PHILIPPINE SEA IN THE EXTENDED TRACK,
INTENSIFICATION CONTINUES, SIMPLY AT A REDUCED RATE. FOR THESE
REASONS THE JTWC INTENSITY FORECAST IS PLACED INITIALLY WITH MEDIUM
CONFIDENCE AND EVENTUALLY WITH LOW CONFIDENCE DUE TO AN INCREASING
DISCREPANCY IN INTENSITY GUIDANCE IN THE EXTENDED FORECAST.

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