WDPN31 PGTW 130900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (MALAKAS) WARNING NR 026//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.9N 137.0E
   INITIAL INTENSITY: 115 KTS
   GEOGRAPHIC REFERENCE: 479 NM SOUTH-SOUTHWEST OF IWO TO
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TY MALAKAS HAS STEADILY INTENSIFIED OVER THE PREVIOUS SIX HOURS,
AND LIKELY REACHED ITS PEAK INTENSITY, BASED ON THE ANIMATED
VISIBLE AND INFRARED IMAGERY, AT AROUND THE 130400Z HOUR.
SUBSEQUENT IMAGERY SHOWS THE EYE FEATURE HAS BECOME MORE RAGGED AND
LESS SYMMETRICAL, AND ALSO BECOMING MORE CLOUD-FILLED SINCE
130400Z. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
NICELY SYMMETRICAL CORE OF CONVECTION WITH AN EXPANSIVE AREA OF
FLARING CONVECTION AND SPIRAL BANDS TO THE EAST, BUT LITTLE TO NO
CONVECTION ON THE WESTERN PERIPHERY, WHERE DRY, STABLE AIR IS
PRECLUDING ANY CONVECTIVE DEVELOPMENT. A 130647Z SSMIS 91GHZ IMAGE
SHOWED A COMPLETE EYEWALL, THOUGH THE NORTHWESTERN SIDE IS WEAK AND
FRAGMENTED, INDICATIVE OF SOME MID-LEVEL DRY AIR TO THE NORTH. THE
IMAGERY ALSO HINTS AT A POSSIBLE SECONDARY EYEWALL BEGINNING TO
DEVELOP, PARTICULARLY ACROSS THE SOUTHERN HALF OF THE CIRCULATION.
THE INITIAL POSITION WAS ASSESSED WITH HIGH CONFIDENCE BASED ON A
19NM MICROWAVE EYE IN A 130532Z GMI 37GHZ IMAGE. THE INITIAL
INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, ABOVE ALL OF THE
AGENCY FIXES, IN A NOD TOWARDS THE SATCON AND AIDT, BUT A BIT BELOW
THE CIMSS ADT VALUES, IN LIGHT OF THE OUTSTANDING MICROWAVE EYE
DEPICTION. THE OVERALL ENVIRONMENT REMAINS FAVORABLE FOR THE TIME
BEING, BUT IS BECOMING INCREASINGLY LESS SO WITH EACH PASSING HOUR.
TY 02W IS TRACKING NORTHEASTWARD ALONG THE WESTERN SIDE A SOUTHWEST
TO NORTHEAST SUBTROPICAL RIDGE (STR) TO THE EAST.

INITIAL WIND RADII BASIS: AMSR2 WINDSPEED PRODUCT

CURRENT STEERING MECHANISM: WESTERN SIDE OF A STEERING SUBTROPICAL
RIDGE (STR) TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T5.5 - 102 KTS
   CIMSS SATCON: 116 KTS AT 130404Z
   CIMSS ADT: 124 KTS AT 130540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: MODERATE EQUATORWARD OUTFLOW AND A DEEP WEDGE OF
DRY AIR ENTRENCHED TO THE WEST OF THE CIRCULATION. 

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: THERE ARE NO SIGNIFICANT CHANGES FORECAST IN
THE TRACK OF TY MALAKAS AND THE SYSTEM WILL CONTINUE TO ACCELERATE
TOWARDS THE NORTHEAST THROUGHOUT THE DURATION OF THE FORECAST
PERIOD. AS MENTIONED, THE ENVIRONMENT IS STILL FAVORABLE FOR THE
TIME BEING, BUT GIVEN THE DECREASING SSTS, REDUCED OHC AND
POTENTIAL FOR A NEAR-TERM EYEWALL REPLACEMENT CYCLE (ERC), THE
SYSTEM HAS LIKELY REACHED ITS PEAK. IN THE NEAR-TERM, THE INTENSITY
IS FORECAST TO REMAIN STEADY THROUGH TAU 12, BUT THEN DROPS OFF
SHARPLY BY TAU 24 AS THE DRY AIR ENTRENCHED TO THE WEST BEGINS TO
NOSE ITS WAY INTO THE CORE OF THE SYSTEM AND IT BEGINS TO THE
DECREASED SSTS AND INCREASED SHEAR BEGIN TO HAVE A SIGNIFICANT
IMPACT. BY TAU 36, SHEAR IS FORECAST TO INCREASE TO ABOVE 35 KNOTS,
AND THE SYSTEM WILL BEGIN TO DECOUPLE, ACCELERATING THE WEAKENING
TREND. SIMULTANEOUSLY THE SYSTEM BEGINS TO INTERACT WITH THE
BAROCLINIC ZONE TO THE NORTH, MARKING THE BEGINNING OF
EXTRATROPICAL TRANSITION (ETT). TY MALAKAS WILL TRANSITION TO A
STRONG GALE-FORCE EXTRATROPICAL LOW NO LATER THAN TAU 72, AND
LIKELY AS EARLY AS TAU 60, WELL EAST OF HONSHU.    

MODEL DISCUSSION: DYNAMIC AND ENSEMBLE TRACK GUIDANCE IS IN VERY
GOOD AGREEMENT, WITH MINIMAL SPREAD OF LESS THAN 150NM EVEN AT TAU
72. ALONG-TRACK SPREAD HAS DECREASED SINCE THE PREVIOUS RUNS, AND
IS ALSO IN GOOD AGREEMENT, LEADING TO OVERALL HIGH CONFIDENCE IN
THE JTWC FORECAST TRACK. WITH THE EXCEPTION OF COAMPS-TC WHICH
SHOWS A NEAR-TERM INTENSIFICATION TO A PEAK OF 120 KNOTS AT TAU
12, THE REMAINDER OF THE INTENSITY GUIDANCE IS ALSO IN GOOD
AGREEMENT ON A STEADY AND RAPID WEAKENING TREND THROUGH THE
FORECAST PERIOD. THE JTWC FORECAST LIES ABOUT FIVE KNOTS ABOVE THE
BULK OF THE GUIDANCE THROUGH TAU 12, THEN LIES SLIGHTLY ABOVE THE
MEAN THROUGH THE REMAINDER OF THE FORECAST WITH HIGH CONFIDENCE. 

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