WDPN31 PGTW 312100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 06W (JANGMI) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.6N 127.4E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 175 NM SOUTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS THE 
REMNANTS OF THE VERY BROAD RAGGED EYE WHICH HAS SLOWLY DEGRADED
OVER THE PAST 6 HOURS, AND A PAIR OF MESOVORTICIES CONTINUING TO
ROTATE CYCLONICALLY AROUND THE BROAD INNER CORE OF THE SYSTEM. 
ANIMATED WATER VAPOR IMAGERY SHOWS A VIGOROUS POLEWARD OUTFLOW CHANNEL 
SUPPORTED BY THE ENTRANCE REGION OF A JET MAX POSITIONED OVER HONSHU 
TO THE NORTH, WHILE THE EQUATORWARD CHANNEL OUTFLOW HAS DECLINED. A 
310927Z WSFM 37 GHZ MICROWAVE IMAGE REVEALS THE RAGGEDNESS OF THE 
REMNANT MICROWAVE EYE AND THE EXTENT OF THE BROAD INNER CORE. THE 
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE CENTROID 
OF THE MESOVORTICES IN ANIMATED MSI AND EXTRAPOLATION FROM THE CENTER 
ANALYZED IN THE WSFM MICROWAVE IMAGE. THE INITIAL INTENSITY OF 70 KTS 
IS ASSESSED WITH MEDIUM CONFIDENCE BASED PRIMARILY ON THE SPREAD OF 
AGENCY DVORAK FIXES AND THE OBSERVED TREND OF LOW CIMSS INTENSITY 
ESTIMATES. THE ENVIRONMENT IS ASSESSED AS MARGINALLY FAVORABLE, WITH 
DECLINING SEA SURFACE TEMPERATURES (SST) BEING OFFSET BY LOW VERTICAL 
WIND SHEAR AND GOOD OUTFLOW ALOFT.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA, SUPPLEMENTED BY THE
OBJECTIVE BEST TRACK

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER 
SUBTROPICAL RIDGE CENTERED NEAR IWO TO.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 69 KTS AT 311800Z
   CIMSS ADT: 33 KTS AT 311800Z
   CIMSS AIDT: 56 KTS AT 311800Z
   CIMSS D-MINT: 63 KTS AT 311706Z
   CIMSS D-PRINT: 63 KTS AT 311800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: SLIGHT DRY AIR ENTRAINMENT FROM THE WEST

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: TYPHOON (TY) 06W (JANGMI) CONTINUES ON A 
GENERALLY NORTHWARD TRAJECTORY AS IT WORKS ITS WAY AROUND THE STEERING 
RIDGE AXIS OVER THE NEXT 12 HOURS. AFTER TAU 12 THE TRACK TURNS 
NORTHEASTWARD AND TAKES THE BROAD CENTER OF THE SYSTEM DIRECTLY OVER 
OKINAWA, MAKING ITS CLOSEST POINT OF APPROACH TO KADENA AB AROUND 
011000Z. FOLLOWING THE NORTHEASTWARD TURN, TY 06W IS FORECAST TO 
ACCELERATE AND TRACK ALONG THE SOUTHERN COAST OF HONSHU ON A PATH THAT 
PUTS THE CENTER ALMOST DIRECTLY OVER YOKOSUKA NEAR TAU 60. THE 
STEERING MECHANISM DURING THIS PERIOD TRANSITIONS TO STRONG GRADIENT 
FLOW AS THE STR MIGRATES SOUTH TOWARD THE MARIANA ISLANDS AND THE 
SYSTEM APPROACHES THE MID-LATITUDE WESTERLIES. TY JANGMI HAS REACHED 
PEAK INTENSITY AND IS EXPECTED TO MAINTAIN 70 KTS IN THE SHORT TERM 
(THROUGH TAU 24) WITH THE VIGOROUS POLEWARD OUTFLOW AND STILL-WARM 
SST. THEN, COOLING SST AND INCREASING VWS INDUCE A STEADY WEAKENING 
TREND. EXTRATROPICAL TRANSITION IS EXPECTED TO BEGIN AFTER TAU 48, 
COMPLETING NO LATER THAN TAU 96.

MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN VERY GOOD AGREEMENT ON
THE RECURVING TRACK AROUND THE STR AXIS THROUGH TAU 24 WITH MINIMAL
CROSS-TRACK AND ALONG-TRACK SPREAD. ALONG-TRACK SPREAD INCREASES TO
125 NM AT TAU 96 AND THE CROSS-TRACK SPREAD INCREASES NOTABLY TO
185 NM BETWEEN TAU 72 AND 96. THIS IS NOT UNEXPECTED GIVEN THE
INHERENT UNCERTAINTY INTRODUCED WITH THE EXTRATROPICAL TRANSITION
SCENARIO AND ASSOCIATED EFFECTS OF BAROCLINIC FORCING. THE JTWC
TRACK FORECAST IS PLACED NEAR THE MULTI-MODEL CONSENSUS WITH HIGH
CONFIDENCE THROUGH TAU 72 AND MEDIUM CONFIDENCE THEREAFTER. THE
MODEL INTENSITY GUIDANCE IS IN OVERALL GOOD AGREEMENT WITH THE
PREVIOUSLY DISCUSSED GRADUAL WEAKENING TREND, MAINTAINING A TIGHT
ENVELOPE OF INTENSITY VALUES WITHIN A 10KT WINDOW THROUGHOUT THE
FORECAST PERIOD. AS A RESULT, THE JTWC INTENSITY FORECAST IS PLACED
CLOSE TO THE CONSENSUS WITH OVERALL HIGH CONFIDENCE.

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