WDPN31 PGTW 260300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 20W (MINDULLE) WARNING 
NR 
015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.6N 136.9E
   INITIAL INTENSITY: 140 KTS
   GEOGRAPHIC REFERENCE: 445 NM SOUTHWEST OF IWO TO
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 40 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN IMPRESSIVE
DEEPENING OF THE CENTRAL CORE, WITH A WELL-FORMED 11 DEGREE CELSIUS
EYE, THAT IS NOW DOWN TO 15 NM DIAMTER. A SENTINEL-1 SAR PASS AT
252048Z PROVIDED EXCEPTIONAL DETAIL OF THE ENTIRE EXPANSE OF
MINDULLES WIND FIELD. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON AGENCY EYE FIXES AND THE AFOREMENTIONED SAR. THE
PRIOR INTENSITY WAS REVISED UPWARDS TO 115 KNOTS, AND THE CURRENT
INTENSITY IS ASSESSED AT 140 KNOTS. THIS IS BASED ON DVORAK
ESTIMATES RANGING FROM T6.5 TO T7.0, WHICH ALIGNS WITH THE NESDIS
STAR FIX PRODUCT BASED ON THE SENTINEL-1 DATA. SATCON AND ADT
ESTIMATES ARE STILL LAGGING BEHIND, BUT BEGINNING TO CATCH UP AT
105 KNOTS AND 110 KNOTS, RESPECTIVELY. THE FOUR-QUADRANT 34, 50,
AND 64 KNOT WIND RADII HAVE BEEN ADJUSTED BASED ON THE SAR
DATA.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: COMPETING STEERING PATTERN, BETWEEN A
SUB-TROPICAL RIDGE TO THE EAST-SOUTHEAST, AND A MID-LATITUDE RIDGE
ANCHORED OVER SOUTHEASTERN CHINA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   RJTD: T6.5 - 127 KTS
   KNES: T6.5 - 127 KTS
   CIMSS SATCON: 110 KTS AT 252135Z
   CIMSS ADT: 104 KTS AT 252340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG RADIAL
   OTHER FACTORS: ENTERING LOWER OHC WATERS OVER THE NEXT 12-24
HOURS

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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, HOWEVER, TAU 0 TO 72
FORECAST POSITS HAVE BEEN ADJUSTED SLIGHTLY SLOWER TO ACCOUNT FOR
THE OBSERVED REDUCTION IN FORWARD TRACK SPEED.

FORECAST DISCUSSION: SUPER TYPHOON 20W IS FORECAST TO CONTINUE
TRACKING GENERALLY NORTHWESTWARD THROUGH TAU 36. TRACK SPEEDS DURING 
THIS TIME ARE EXPECTED TO BE SLOW DUE TO THE STR OVER CHINA IMPEDING 
FORWARD MOTION. BEGINNING AFTER TAU 36, THIS STR IS EXPECTED TO 
SLOWLY SETTLE TO ITS SOUTHWEST, WHILE THE RIDGING TO THE EAST WILL 
BUILD IN, RESULTING IN A MORE NORTHERLY TRACK. BEYOND TAU 72, 
MINDULLE WILL ACCELERATE TO THE NORTHEAST AS IT BECOMES WEDGED 
BETWEEN AN ADVANCING TROUGH OVER JAPAN AND THE SUB-TROPICAL RIDGING 
TO THE EAST. THE HIGH-AMPLITUDE PATTERN OF THE STR MEANS THAT 20W 
MAY HAVE A GRADUAL EXTRA-TROPICAL TRANSITION (ETT). THE CURRENT 
FORECAST CALLS FOR ETT TO BEGIN AT TAU 120. THE SYSTEM LIKELY HAS 
ABOUT ANOTHER 12 TO 24 HOURS LEFT TO SUPPORT SUPER TYPHOON INTENSITY
BEFORE UPWELLING, COMBINED WITH SLOW FORWARD MOTION AND COOLING OHC
VALUES, BEGINS A GRADUAL WEAKENING TREND. THIS FORECAST DOES NOT 
ACCOUNT FOR ANY POTENTIAL EYEWALL REPLACEMENT CYCLE(S), WHICH ARE A 
POSSIBILITY, BUT NOT OBSERVED AT THIS TIME. BEYOND TAU 72, WEAKENING 
SHOULD BECOME MORE PRONOUNCED AS 20W ENCOUNTERS DECREASED OUTFLOW 
ALOFT AND INCREASING MID-LEVEL SHEAR. THE PRIMARY MODEL GROUPING AND 
NEARLY ALL MEMBERS OF THE GFS AND ECMWF ENSEMBLES KEEPS THE CENTER 
OF THE TRACK EAST OF JAPAN. EVEN SO, THE EXPANSIVE 35 KNOT WIND 
FIELD COVERS MUCH OF EASTERN HONSHU, WITH STORM FORCE WINDS POSSIBLE 
ALONG THE COAST. 


MODEL DISCUSSION: MODEL SOLUTIONS ARE IN MODERATELY GOOD AGREEMENT,
BOTH IN ALONG AND CROSS TRACK SPREAD. THE FIVE-DAY SPREAD IS 250 NM. 
THE FORECAST TRACK IS THEREFORE PLACED CLOSE TO THE MULTI-MODEL
CONSENSUS. UNLIKE TRACK, MODELS ARE STRUGGLING WITH THE INTENSITY,
PARTIALLY BECAUSE THE ANALYZED WINDS ARE TOO WEAK. THE INTENSITY
FORECAST IS THEREFORE PLACED HIGHER THAN THE INTENSITY CONSENSUS. 

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