WDPN31 PGTW 030300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (JANGMI) WARNING NR 
028//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 34.2N 137.8E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 115 NM SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 25 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM (TS) 06W (JANGMI) TRANSITING THE SOUTHERN COAST OF JAPAN AT A
HIGH (23 KTS) TRANSLATIONAL SPEED. ENVIRONMENTAL ANALYSIS SHOWS TS
06W EXPERIENCING HIGH (30-35 KTS) MID-LEVEL VERTICAL WIND SHEAR
(VWS), FORCING DRY AIR INTO THE SOUTHWESTERN QUADRANT IN ADDITION
TO COLD (22-23 C) SEA SURFACE TEMPERATURES (SSTS), ONLY OFFSET BY
THE HIGH POLEWARD OUTFLOW BEING PROVIDED BY THE UPPER-LEVEL JET
SITUATED JUST NORTH OF TS JANGMI. THE INITIAL POSITION IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON A COMBINATION OF MSI IMAGERY,
VARIOUS AGENCY SATELLITE AND RADAR FIXES, SURFACE OBSERVATIONS FROM
STATIONS ALONG THE ENSHU-NADA SEA, AND A PARTIAL 022324Z GMI 89 GHZ
IMAGE SHOWING THE NORTHERN PORTION OF BANDING, ALBEIT WITH A
SLIGHTLY DECEPTIVE CENTER-LOOKING FEATURE NORTH OF THE JTWC
POSITON. THE INITIAL INTENSITY IS ALSO ASSESSED WITH MEDIUM
CONFIDENCE BASED ON SURFACE OBSERVATIONS FROM THE ISLANDS OF
HACHIJOJIMA AND MIYAKEJIMA REPORTING 35-40 KT SUSTAINED WINDS AND A
MAX WIND GUST OF 65 KTS AROUND 2200Z, AS WELL AS A PARTIAL 030000Z
METOP-B ASCAT PASS SHOWING 40 KT WINDS AS FAR AS 100 NM FROM THE
LOW-LEVEL CIRCULATION CENTER (LLCC).

INITIAL WIND RADII BASIS: ADJUSTED 50 KT WIND RADII BASED ON
SURFACE OBSERVATIONS

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE SOUTHWEST OF THE SYSTEM

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.5 - 35 KTS
   CIMSS ADT: 32 KTS AT 0100Z
   CIMSS AIDT: 41 KTS AT 0100Z
   CIMSS D-MINT: 46 KTS AT 2113Z
   CIMSS D-PRINT: 49 KTS AT 0100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 30-35 KTS
   SST: 22-23 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: SIGNIFICANT DRY AIR ENTRAINMENT IN THE WESTERN
AND SOUTHERN QUADRANTS

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TS JANGMI IS FORECAST TO CONTINUE FOLLOWING
THE SOUTHERN COAST OF HONSHU, MAKING LANDFALL TWO TO THREE MORE
TIMES BEFORE EMERGING OVER OPEN WATER BY TAU 12. IT IS CURRENTLY
UNDERGOING EXTRATROPICAL TRANSITION (ETT), AS EVIDENCED BY ITS
HIGHLY SHEARED APPEARANCE, INTERACTION WITH THE UPPER-LEVEL JET
STREAM, AND BEGINNINGS OF TEMPERATURE ADVECTION. IT IS FORECAST TO
COMPLETE ETT BY TAU 24 AS IT BECOMES FULLY EMBEDDED UNDERNEATH THE
JET, WITHIN SSTS OF 22 C OR LESS, AND CONTINUED DRY AIR ENTRAINMENT
DUE TO HIGH VWS. IN TERMS OF INTENSITY, TS 06W IS EXPECTED TO
MAINTAIN INTENSITIES ABOVE 40 KTS FOR THE REMAINDER OF THE FORECAST
PERIOD, WEAKENING ONLY SLIGHTLY AS IT COMPLETES ETT.

MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN GOOD AGREEMENT FOR THE
REMAINDER OF THE FORECAST PERIOD, WITH A MAXIMUM CROSS-TRACK SPREAD
OF 40 NM AND ALONG-TRACK SPREAD OF 60 NM. THE OFFICIAL JTWC TRACK
FORECAST IS PLACED WITH HIGH CONFIDENCE, IN LINE WITH THE
MULTI-MODEL CONSENSUS. THE INTENSITY MODEL GUIDANCE IS IN GOOD
AGREEMENT AS WELL, INDICATING A GRADUAL WEAKENING TREND FOR THE
REMAINDER OF THE FORECAST. THE OFFICIAL JTWC INTENSITY FORECAST IS
ASSESSED WITH MEDIUM CONFIDENCE, ABOVE THE MULTI-MODEL CONSENSUS IN
LINE WITH HAFS AND OTHER MESOSCALE MODELS.

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