WDPN31 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (MALAKAS) WARNING NR 027//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.8N 137.6E
   INITIAL INTENSITY: 115 KTS
   GEOGRAPHIC REFERENCE: 415 NM SOUTH-SOUTHWEST OF IWO TO
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TY MALAKAS HAS NOT APPRECIABLY CHANGED OVER THE PAST SIX HOURS,
WITH THE EYE REMAINING AT A STEADY 25NM WIDE AND THE CONVECTIVE
SIGNATURE REMAINING RELATIVELY STAGNANT. HOWEVER, BY THE 131330Z
HOUR, ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SUGGESTS
SOME EROSION OF THE CONVECTIVE ACTIVITY ON THE EASTERN SIDE OF THE
SYSTEM, WITH THE OVERALL STRUCTURE BECOMING LESS SYMMETRICAL. DUE
TO A TECHNICAL GLITCH, THERE IS NO MICROWAVE IMAGERY AVAILABLE TO
PEER INTO THE INNARDS OF THE SYSTEM, BUT THE WIDE, CLEAR EYE
PROVIDED HIGH CONFIDENCE TO THE INITIAL POSITION. THE INITIAL
INTENSITY REMAINS SET AT 115 KNOTS, WITH MEDIUM CONFIDENCE. OVERALL
THERE HAS BEEN NO SIGNIFICANT CHANGE IN EITHER THE OBJECTIVE DVORAK
CURRENT INTENSITY ESTIMATES BETWEEN T5.0 TO T5.5 OR THE SUBJECTIVE
ADT ESTIMATES AT T6.2, 119 KNOTS. OVER THE PAST FEW HOURS, THE EYE
TEMPS HAVE BEEN AS HIGH AS 14C, THOUGH THE CLOUD TOPS OF AT THE
SAME TIME WARMED, AND THUS NO REAL CHANGE IN THE INTENSITY
ESTIMATES. THE SYSTEM HAS TAKEN A BIT OF A JOG MORE TOWARDS DUE
NORTH OVER THE PAST COUPLE OF HOURS BUT THE COURSE MADE GOOD
REMAINS NORTH-NORTHEASTWARD AT A MODERATE CLIP OF 11 KNOTS. THE
ENVIRONMENT IS BECOMING INCREASINGLY MARGINAL, WITH AN UPPER-LEVEL
ANTICYCLONE TO THE WEST AND A LARGE WEDGE OF DRY, STABLE AIR,
FIRMLY ENSCONCED TO THE WEST COMBINING TO IMPINGE ON THE CORE FROM
THE WEST AND INHIBIT OUTFLOW TO THE WEST.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   RJTD: T5.5 - 102 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T5.5 - 102 KTS
   CIMSS ADT: 119 KTS AT 131140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: LIMITED OUTFLOW AND SIGNIFICANT DRY AIR ON THE
WESTERN SIDE OF THE CIRCULATION. 

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TIMES WERE GOOD WHILE THEY LASTED, BUT THE
GOOD TIMES ARE RAPIDLY COMING TO AN END FOR TY MALAKAS. THE SYSTEM
HAS REACHED ITS PEAK, AND ENVIRONMENTAL CONDITIONS ARE QUICKLY
BECOMING MORE MARGINAL AS THE SYSTEM ACCELERATES TO THE NORTHEAST.
THE FIRST SIGN OF THE EROSION OF THE CORE ARE ALREADY BEING SEEN IN
THE RECENT ANIMATED EIR, AND THE DRY AIR ON THE WEST SIDE LOOKS TO
BE ENCROACHING EVER NEARER TO THE CORE, STARTING TO WRAP IN ALONG
THE SOUTHERN SIDE AS WELL. WHILE SHEAR REMAINS RELATIVELY LOW FOR
NOW, IT IS TRENDING UPWARDS AND THIS OVERALL TREND OF INCREASING
DRY AIR ENTRAINMENT AND SHEAR IS FORECAST TO CONTINUE AT A STEADILY
QUICKENING RATE THROUGH THE FORECAST PERIOD. ADDITIONALLY, THE
SYSTEM IS EXPECTED TO CROSS THE 26C ISOTHERM BY TAU 24, CUTTING OFF
THE ENERGY SUPPLY FOR CONTINUED TROPICAL CYCLONE DEVELOPMENT. SHEAR
VALUES ARE FORECAST TO INCREASE ABOVE 35 KNOTS BY 48 AND THE SYSTEM
WILL BE DECAPITATED, AS IT SIMULTANEOUSLY BEGINS TO UNDERGO
EXTRATROPICAL TRANSITION (ETT) AS IT MOVES INTO THE SOUTHERN
REACHES OF A STRONG BAROCLINIC ZONE. TRANSITION TO A STRONG
GALE-FORCE COLD-CORE EXTRATROPICAL LOW PRESSURE AREA IS EXPECTED TO
BE COMPLETE NO LATER THAN TAU 72 AND LIKELY AS EARLY AS TAU 60 AS
THE SYSTEM BECOMES EMBEDDED WITHIN THE 200MB POLAR FRONT JET STREAM
AND DEVELOPS STRONG FRONTAL CHARACTERISTICS.

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE IS IN
VERY GOOD AGREEMENT THROUGH THE DURATION OF THE FORECAST PERIOD,
WITH MINIMAL CROSS-TRACK SPREAD. ACROSS-TRACK SPREAD REMAINS VERY
CONSISTENT, WITH THE CONSENSUS MEMBERS TIGHTLY PACKED EVEN AT TAU
72. CONFIDENCE IN THE FORECAST TRACK IS THUS ASSESSED AS HIGH.
AVAILABLE INTENSITY GUIDANCE IS SOMEWHAT LIMITED ON THIS CYCLE, BUT
OVERALL THE AVAILABLE MODELS ALL CONCUR ON RAPID WEAKENING THROUGH
THE FORECAST PERIOD. THE JTWC FORECAST CONCURS WITH THE OVERALL
SCENARIO BUT DEPARTS FROM THE CONSENSUS MEAN, WITH A SLIGHTLY
SLOWER RATE OF WEAKENING. CONFIDENCE IN THE INTENSITY FORECAST IS
ASSESSED AS MEDIUM. 

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