WDPN33 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (NEOGURI) WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.8N 153.8E
   INITIAL INTENSITY: 120 KTS
   GEOGRAPHIC REFERENCE: 885 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 32 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TYPHOON NEOGURI HAS SHATTERED THE GLASS CEILING AND UNDERGONE
EXPLOSIVE INTENSIFICATION (EI), PLUSSING UP 55 KTS IN THE PAST 24
HRS. STRONG, RADIAL OUTFLOW AND A SYMMETRIC, COMPACT CDO SURROUND
THIS WRATHFUL MAELSTROM. A LARGE, CLEAR, AXISYMMETRICAL EYE FEATURE
HAS HAD IMPROVING CLARITY AND WAS MEASURED TO HAVE A TEMPERATURE OF
19C. THIS WAS A FEW DEGREES WARMER THAN PREVIOUSLY MEASURED, WHICH
SUPPORTS THE CLEARING TREND OBSERVED IN RECENT HOURS. MICROWAVE AND
EIR IMAGERY SHOW THE STRONG CENTRAL STRUCTURE IS SURROUNDED BY
BURSTING CONVECTIVE BANDS IN ALL QUADRANTS. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE. THE INITIAL
INTENSITY OF 120 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON VERY
GOOD AGREEMENT OF AGENCY SUBJECTIVE DVORAK FIXES AND IS SUPPORTED
BY THE RANGE OF OBJECTIVE ESTIMATES.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE EAST-NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   RJTD: T6.5 - 127 KTS
   RCTP: T6.5 - 127 KTS
   KNES: T6.5 - 127 KTS
   CIMSS SATCON: 117 KTS AT 201515Z
   CIMSS ADT: 119 KTS AT 201730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG RADIAL

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 25W HAS ENJOYED FREE REIGN WITHIN A
HIGHLY FAVORABLE ENVIRONMENT OF ANOMALOUSLY WARM SST AND LOW
VERTICAL WIND SHEAR. THIS ENVIRONMENT WILL PERSIST IN THE SHORT
TERM AND ALLOW NEOGURI TO THRIVE. THE MAIN QUESTION IS CONCERNING
THE STEERING MECHANISM. CURRENTLY DRIVEN BY THE SUBTROPICAL RIDGE
TO THE EAST-NORTHEAST, A RECURVE TRACK IS EXPECTED BETWEEN TAU 24
AND TAU 36. THERE REMAINS A SLIGHT POSSIBILITY THAT THE BONIN HIGH
TO THE NORTHWEST COULD INTERFERE BY SLOWING THE TRACK OR DRIVING
THE SYSTEM WESTWARD, BUT THE INITIAL BIFURCATION SCENARIO HAS
BACKED OFF AND RETURNED TO THE ORIGINAL FORECAST PHILOSOPHY THAT A
STANDARD RECURVE WILL ENSUE. A MIDLATITUDE TROUGH IS EXPECTED TO
DISRUPT THE SUBTROPICAL RIDGE TO THE EAST, HENCE THE SLIGHT S-CURVE
THAT IS STARTING TO EMERGE IN THE TRACK FORECAST IN THE LATER TAUS.
TOWARDS TAU 96, WEAK BAROCLINICITY IS INTRODUCED INTO THE SYSTEM.
FRONTOGENSIS IS EXPECTED TO BEGIN NEAR TAU 120, WHICH IS WHY A
TRANSITION TO EXTRATROPICAL IS EXPECTED TO BEGIN THEN.

MODEL DISCUSSION: TRACK GUIDANCE STILL SHOWS A POSSIBILITY FOR A
RADICAL CHANGE IN STEERING MECHANISMS, WITH PARTICULARLY THE ECMWF
PICKING UP ON A SUDDEN WESTWARD TRACK AFTER A PIVOT POINT AT TAU
48. ALL OTHER MODEL GUIDANCE IS LOCKED INTO THE SUBTROPICAL RIDGE
TO THE NORTH HOLDING ONTO THE TRACK CONTROL WITH A RECURVE AROUND
TAU 24-36 AND A POTENTIAL S-CURVE TRACK DURING THE NORTHWARD
PROGRESSION. THE JTWC FORECAST IN THE LATER TAUS IS ADJUSTED WEST
FROM THE PREVIOUS FORECAST, WHICH BRINGS IT CLOSER TO THE CONSENSUS
AND AI TRACK AIDS. ASIDE FROM THE ECMWF, TRACK SPREAD IS TIGHT AT
LESS THAN 100 NM THROUGH TAU 48 AND 200 NM AT TAU 72, LEADING TO A
HIGH CONFIDENCE FORECAST THROUGH TAU 72 AND DECREASING THEREAFTER.
FEWER RI AIDS TRIGGERING INDICATE THE RAPID INTENSIFICATION SEGMENT
MAY BE ENDING SOON, AND THE MAJORITY OF INTENSITY AIDS SHOW THE
SYSTEM LEVELING OFF AT A PEAK BETWEEN TAU 12 AND TAU 24, WITH A
GRADUAL DECLINE AFTERWARDS.

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