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JTWC/25W/#39/09-28 00Z Prognostic Reasoning
WDPN33 PGTW 280300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (NEOGURI) WARNING NR 039//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 34.3N 162.4E
INITIAL INTENSITY: 95 KTS
GEOGRAPHIC REFERENCE: 927 NM NORTH-NORTHWEST OF WAKE ISLAND
MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 19 KTS
SIGNIFICANT WAVE HEIGHT: 43 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PERFECTLY
ROUND, 15NM WIDE EYE FEATURE, EMBEDDED WITHIN A COMPACT CENTRAL
DENSE OVERCAST (CDO). A 272113Z GMI 89GHZ MICROWAVE IMAGE REVEALED
A COMPLETELY ENCLOSED EYEWALL, WITH THE DEEPEST AND STRONGEST
CONVECTION LOCATED IN THE SOUTHEASTERN QUADRANT AND WELL-DEFINED
SPIRAL BANDING FEATURES, PARTICULARLY EVIDENT TO THE NORTHWEST.
ANIMATED WATER VAPOR IMAGERY SHOWS EXTREMELY STRONG POLEWARD
OUTFLOW STRETCHING FAR OFF TO THE NORTHEAST, INTO THE ENTRANCE
REGION OF A 100 KNOT JET MAX. THE INITIAL POSITION IS ASSESSED WITH
HIGH CONFIDENCE BASED ON THE 15NM WIDE EYE FEATURE AND
EXTRAPOLATION OF THE EARLIER GMI MICROWAVE EYE. THE INITIAL
INTENSITY IS ASSESSED WITH HIGH CONFIDENCE, CLOSE TO THE ADT VALUE
OF T5.4 AND CONSISTENT WITH THE T5.5 DVORAK CURRENT INTENSITY
ESTIMATES FROM KNES, RJTD AND RCTP. ENVIRONMENTAL CONDITIONS REMAIN
FAVORABLE, BUT THE FAVORABLE CONDITIONS WILL NOT LAST MUCH LONGER.
SHEAR IS ALREADY STARTING TO PICK UP TO MORE MODERATE VALUES, BUT
SO FAR IS STILL OFFSET BY THE ROBUST POLEWARD OUTFLOW. SSTS ARE
STILL SUPPORTIVE BUT QUICKLY BECOMING MARGINAL.
INITIAL WIND RADII BASIS: PERSISTENCE
CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T5.0 - 90 KTS
RJTD: T5.5 - 102 KTS
RCTP: T5.5 - 102 KTS
KNES: T5.5 - 102 KTS
CIMSS ADT: 99 KTS AT 280100Z
CIMSS AIDT: 98 KTS AT 280100Z
CIMSS D-MINT: 84 KTS AT 272239Z
CIMSS D-PRINT: 94 KTS AT 280100Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 15-20 KTS
SST: 26-27 CELSIUS
OUTFLOW: STRONG POLEWARD
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: TYPHOON (TY) 25W IS PUTTING ON ONE LAST SHOW,
HAVING RAPIDLY INTENSIFIED FROM 55 KNOTS 24 HOURS AGO TO 95-100
KNOTS CURRENTLY, AN IMPRESSIVE FEAT FOR A STORM THIS FAR NORTH. THE
SYSTEM HAS REACHED THE RIDGE AXIS AND HAS BEGUN TO ACCELERATE
TOWARDS THE NORTHEAST. THIS TREND IS EXPECTED TO CONTINUE THROUGH
THE MAJORITY OF THE FORECAST PERIOD, WITH ONLY A SLIGHT DECREASE IN
FORWARD SPEED ANTICIPATED BY THE END OF THE FORECAST PERIOD AS THE
SYSTEM MOVES INTO A POSITION NORTH OF THE STR. AS MENTIONED ABOVE,
ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE BUT WILL NOT LAST MUCH
LONGER. RAPID DETERIORATION IN THE ENVIRONMENT IS EXPECTED,
BEGINNING WITHIN THE NEXT 12 HOURS. SHEAR IS ALREADY STARTING TO
INCREASE AND THE SYSTEM WILL CROSS INTO SUB-26C WATERS WITHIN THE
NEXT 12 HOURS. HOWEVER, POLEWARD OUTFLOW IS SO STRONG, THAT IT WILL
BE ABLE TO OFFSET THE SHEAR FOR A BIT LONGER. BY TAU 24 HOWEVER,
THE SHEAR IS EXPECTED TO BE SO HIGH THAT IT WILL OVERWHELM THE
POSITIVE EFFECTS OF THE STRONG OUTFLOW AND BEGIN TO TEAR THE SYSTEM
APART. EXTREMELY DRY AIR MOVES IN VERY QUICKLY AROUND TAU 24 AS
WELL, AND THE COMBINATION GUT PUNCH (DRY AIR) AND UPPER-CUT (SHEAR)
WILL VERY QUICKLY SERVE THE KNOCK-OUT BLOW TO TY 25W. THE SYSTEM
WILL BEGIN EXTRATROPICAL TRANSITION (ETT) WITHIN THE NEXT 24 HOURS
AND GLOBAL PHASE-SPACE DIAGRAMS AND MODEL DIAGNOSTICS INDICATE AN
EXTREMELY RAPID ETT, WITH TY 25W EXPECTED TO COMPLETE TRANSITION
INTO A COLD-CORE STORM-FORCE LOW BY TAU 36.
MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE REMAINS
IN VERY GOOD AGREEMENT THROUGHOUT THE FORECAST PERIOD, WITH MINIMAL
CROSS- OR ALONG-TRACK DISPERSION. THE JTWC FORECAST IS POSITIONED
CLOSE TO THE CONSENSUS MEAN THROUGH THE DURATION OF THE FORECAST,
WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT,
WITH THE HAFS-A AND COAMPS-TC INDICATING A SMALL AMOUNT OF
ADDITIONAL INTENSIFICATION THROUGH TAU 12, FOLLOWED BY EXTREMELY
RAPID WEAKENING THROUGH THE REMAINDER OF THE FORECAST. THE JTWC
FORECAST IS CONSISTENT WITH THE HAFS-A AND IN FACT THE SYSTEM HAS
MOST LIKELY ALREADY BREACHED THE 100 KNOT THRESHOLD AS OF THE
CURRENT TIME.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
INTENSITY 00-72 HR: HIGH//
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