WDPN31 PGTW 290900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (DOLPHIN) WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.5N 168.4E
   INITIAL INTENSITY: 120 KTS
   GEOGRAPHIC REFERENCE: 210 NM NORTH-NORTHWEST OF UTIRIK
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON (TY)
12W QUICKLY RECOVERING FROM ITS EYEWALL REPLACEMENT CYCLE, WITH THE
LARGER SECONDARY EYE ALREADY BEGINNING TO CLEAR IN ANIMATED IMAGERY.
THE CENTRAL DENSE OVERCAST REMAINS SLIGHTLY ASYMMETRIC, WITH THE
COLDEST CLOUD TOPS (NEARING -90C) CONFINED TO THE SOUTHERN PERIPHERY,
BUT QUICKLY SPREADING. 12W APPEARS TO BE GEARING UP FOR ANOTHER
IMPRESSIVE BOUT OF INTENSIFICATION BUT WILL NEED A LITTLE MORE TIME TO
FURTHER CONSOLIDATE. THE 290513Z SSMIS MICROWAVE DATA REVEALS 12W
REMAINS VERTICALLY STACKED WITH A TIGHT CORE. THE ENVIRONMENT REMAINS
EXCEPTIONALLY FAVORABLE, CHARACTERIZED BY LOW (10-15 KTS) VERTICAL
WIND SHEAR (VWS), WARM (29-30 C) SEA SURFACE TEMPERATURES (SST), AMPLE
OCEAN HEAT CONTENT (OHC), AND VIGOROUS DUAL-CHANNEL OUTFLOW. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE PINHOLE
MICROWAVE EYE IN THE PREVIOUSLY MENTIONED SSMIS PASS. THE INITIAL
INTENSITY OF 120 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
AGENCY DVORAK FIXES AND CIMSS ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE

CURRENT STEERING MECHANISM: THE SOUTHWESTERN PERIPHERY OF A
DEEP-LAYER SUBTROPICAL RIDGE (STR) COMPLEX OVER THE CENTRAL NORTH
PACIFIC

AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T6.5 - 127 KTS
   RJTD: T5.5 - 102 KTS
   KNES: T6.5 - 127 KTS
   CIMSS ADT: 102 KTS AT 290630Z
   CIMSS AIDT: 101 KTS AT 290630Z
   CIMSS D-MINT: 123 KTS AT 290513Z
   CIMSS D-PRINT: 116 KTS AT 290500Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG DUAL-CHANNEL

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: TY 12W (DOLPHIN) WILL MAINTAIN A NORTHWESTWARD
TRAJECTORY THROUGH TAU 96, STEERED ALONG THE SOUTHWESTERN PERIPHERY OF
A COMPLEX RIDGE OVER THE CENTRAL NORTH PACIFIC. BETWEEN TAU 96-120,
THE LONGWAVE TROUGH CURRENTLY DIGGING INTO THE STEERING STR COMPLEX
WILL WEAKEN, ALLOWING FOR THE STR TO REBUILD TO THE NORTHEAST OF THE
SYSTEM AND DEVELOP A WESTWARD EXTENSION. THIS CHANGE IN THE STEERING
PATTERN WILL INDUCE A SLIGHT WESTWARD TURN AT TAU 120. REGARDING
INTENSITY, DOLPHIN IS EXPECTED TO BEGIN A SECOND ROUND OF RAPID
INTENSIFICATION (RI) AS IT TRACKS FURTHER INTO THE INCREASINGLY IDEAL
ENVIRONMENT. THE PEAK INTENSITY IS CURRENTLY FORECAST TO BE 150 KTS
BETWEEN TAU 36-72, BUT A PEAK INTENSITY HIGHER THAN FORECAST MAY OCCUR
AROUND TAU 60, GIVEN THE EXCELLENT ENVIRONMENTAL CONDITIONS. 12W IS
FORECAST TO WEAKEN FROM TAU 72 ONWARD, AS IT ENCOUNTERS SLIGHTLY LOWER
OHC VALUES AND CONTENDS WITH ITS OWN COLD WAKE. ADDITIONAL EYEWALL
REPLACEMENT CYCLES (ERC) ARE POSSIBLE AND WOULD INTRODUCE
UNPREDICTABLE INTENSITY FLUCTUATIONS THAT MAY NOT BE PRESENTLY
REFLECTED IN THE OFFICIAL FORECAST.

MODEL DISCUSSION: DETERMINISTIC TRACK MODEL GUIDANCE IS IN STRONG
AGREEMENT THROUGHOUT THE FORECAST, WITH LESS THAN 200NM CROSS-TRACK
SPREAD AT TAU 120. ALONG-TRACK SPREAD REMAINS MINIMAL FOR THE DURATION
OF THE FORECAST PERIOD. AS A RESULT, THE JTWC TRACK FORECAST IS PLACED
WITH HIGH CONFIDENCE FROM TAU 0-72 AND MEDIUM CONFIDENCE FROM TAU 72-
120. THE UNCERTAINTY IN THE LATE-TERM FORECAST STEMS FROM THE SHIFTING
STEERING INFLUENCES NEAR THE END OF THE FORECAST. RELIABLE INTENSITY
AIDS ARE IN MODERATE AGREEMENT. MESOSCALE MODELS HAFS-A, COAMPS-TC
(GFS BOUNDARY CONDITIONS), AND COAMPS-TC (NAVGEM BOUNDARY CONDITIONS),
DEPICT PEAK INTENSITIES RANGING FROM 140-150 KTS, WHILE GLOBAL MODELS
LAG BEHIND. THE JTWC INTENSITY FORECAST LIES SLIGHTLY HIGHER, BUT VERY
CLOSE TO, THE PREVIOUSLY MENTIONED MESOSCALE MODELS WITH OVERALL LOW
CONFIDENCE. UNCERTAINTIES SURROUNDING THE SECOND ROUND OF RI AND PEAK
INTENSITY HAVE DEGRADED THE INTENSITY FORECAST CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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