Advisories

WDPN31 PGTW 080300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (DOLPHIN) WARNING NR 049//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.0N 126.0E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 101 NM WEST-NORTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 35 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON (TY)
12W (DOLPHIN) HAVING LOST ITS VISIBLE EYE FEATURE WHILE MAINTAINING
A COMPACT CENTRAL CORE. A PARTIAL BAND OF RELATIVELY DRY AIR REMAINS 
PERSISTENT OUTSIDE THIS CORE BUT BEYOND THAT, TY 12W HAS MAINTAINED 
STRONG BANDING FEATURES WITH A CONVECTIVE STRUCTURE SPANNING OVER 600 
NM IN DIAMETER. A 072134Z SENTINEL SAR IMAGE DEPICTS THIS EXTREMELY 
COMPACT CORE WITH A 10 NM RADIUS OF MAXIMUM WINDS AS WELL AS AN AREA 
OF CONSISTENTLY LOW WINDS IN THE SOUTHWEST QUADRANT. ENVIRONMENTAL 
ANALYSIS REVEALS MARGINALLY FAVORABLE CONDITIONS WITH LOW (5-10 KTS) 
VERTICAL WIND SHEAR (VWS), AND WARM (29-30 C) SEA SURFACE TEMPERATURES 
OFFSET BY MARGINAL DRY AIR ENTRAINMENT AND DECREASED OUTFLOW ALOFT. 
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 
COMBINATION OF SATELLITE IMAGERY. THE INITIAL INTENSITY IS ASSESSED 
WITH MEDIUM CONFIDENCE BASED ON THE INCREASED SPREAD BETWEEN SAR 
IMAGERY DEPICTING A 69 KT WIND MAXIMUM, AGENCY DVORAK FIXES, AND CIMSS 
OBJECTIVE ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: WIND RADII ADJUSTED BASED ON A 072134Z
SAR IMAGE.

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A SUBTROPICAL
RIDGE CENTERED OVER HONSHU.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T5.0 - 90 KTS
   CIMSS SATCON: 77 KTS AT 072330Z
   CIMSS ADT: 72 KTS AT 072330Z
   CIMSS AIDT: 80 KTS AT 2330Z
   CIMSS D-MINT: 86 KTS AT 072119Z
   CIMSS D-PRINT: 71 KTS AT 080000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: MODERATE DRY AIR ENTRAINMENT

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: TY 12W HAS RESUMED A MORE DIRECT NORTHWESTWARDLY 
TRACK AS IT CONTINUES THROUGH THE EAST CHINA SEA AND IS FORECAST TO 
MAKE LANDFALL ON EASTERN CHINA BETWEEN TAUS 36 AND 48. IT IS LIKELY 
THAT TY 12W WILL CONTINUE TO WOBBLE WHILE PROCEEDING IN AN OVERALL 
WESTWARD MOTION, DUE TO THE COMBINED STEERING INFLUENCES OF THE 
DOMINANT SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) CENTERED 
OVER HONSHU, AS WELL AS A STR CENTERED OVER NORTHEASTERN CHINA. NEAR 
THE END OF THE FORECAST PERIOD, TY 12W IS FORECAST TO BEGIN RECURVING 
POLEWARD AROUND AN EXTENSION OF THE FORMER STR. IN REGARDS TO 
INTENSITY, TY 12W IS EXPECTED TO MAINTAIN ITS INTENSITY IN THE SHORT 
TERM BEFORE BEGINNING A SHARP DECLINE AS IT APPROACHES LANDFALL AT TAU 
36. ONCE OVER LAND IN CHINA, TY 12W IS FORECAST TO DISSIPATE NO LATER 
THAN TAU 96 DUE TO TERRAIN INTERACTION, WITH A LOW POSSIBILITY OF
REEMERGENCE OVER WATER.

MODEL DISCUSSION: TRACK MODEL GUIDANCE IS IN GOOD AGREEMENT FOR THE
REMAINDER OF THE FORECAST PERIOD WITH THE EXCEPTION OF NAVGEM. 
DISREGARDING NAVGEM AS AN OUTLIER, CROSS TRACK SPREAD AT TAU 96 IS
175 NM. THEREFORE, THE OFFICIAL JTWC FORECAST IS LAID WITH HIGH 
CONFIDENCE FOR THE REMAINDER OF THE FORECAST PERIOD, CLOSELY IN LINE 
WITH THE MULTI-MODEL CONSENSUS EXCLUDING NAVGEM, AS WELL AS THE 
EXPERIMENTAL GOOGLE DEEP MIND AI MODEL. INTENSITY MODEL GUIDANCE IS 
ALSO IN GOOD AGREEMENT WITH A CONSISTENT SPREAD OF 15 KTS BETWEEN ALL 
MODELS THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD, ALL DEPICTING 
A PLATEAU OR SMALL WEAKENING TREND IN THE SHORT TERM FOLLOWED BY A 
SHARP DECREASE IN INTENSITY FROM TAUS 36 TO 48 AS TY 12W MAKES 
LANDFALL. ALL MODEL GUIDANCE IS ALSO IN GOOD AGREEMENT OF TY 12W 
DISSIPATING AT OR BEFORE TAU 96, THUS THE OFFICIAL JTWC INTENSITY 
FORECAST IS ASSESSED WITH HIGH CONFIDENCE, CLOSELY IN LINE WITH THE 
MULTI-MODEL CONSENSUS. 

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