WPAC: NARI - Post-Tropical

[Yellow Evan]

Exactly what we need. Another sheared mess to track.

[Hayabusa]

I was surprised that it got upgraded fast to a warning system by JMA, only to develop to another not looking good TS.

[euro6208]

WDPN31 PGTW 260900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (NARI) WARNING
NR 006//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 07W (NARI), LOCATED APPROXIMATELY 314 NM SOUTHWEST OF
YOKOSUKA, JAPAN, HAS TRACKED NORTH-NORTHWESTWARD AT 13 KNOTS OVER THE
PAST SIX HOURS. THE CURRENT POSITION MARKS A DEFINED LOW LEVEL
CIRCULATION CENTER (LLCC) EVIDENT IN 260600Z MULTISPECTRAL SATELLITE
IMAGERY, RADAR DATA AND A 260558Z SSMI PASS. THE INTENSITY OF 35
KNOTS IS CONSISTENT WITH A CONSENSUS OF MULTI-AGENCY SUBJECTIVE
DVORAK SATELLITE INTENSITY ESTIMATES AND EARLIER SCATTEROMETER DATA
INDICATING EXTENSIVE AREAS OF 30 TO 35 KNOT WINDS ASSOCIATED WITH THE
CIRCULATION. AN INFUSION OF DRIER AIR FROM THE WEST AND MODERATE
VERTICAL WIND SHEAR (15-20 KNOTS) HAVE LEFT THE LLCC OF TS 07W
PARTIALLY-EXPOSED. HOWEVER, PASSAGE OVER WARM WATER (28-29C) AND
GENERALLY FAVORABLE DIFFLUENCE ALOFT HAVE BALANCED THESE NEGATIVE
IMPACTS OVER THE PAST SIX HOURS, ENABLING TS 07W TO MAINTAIN
INTENSITY AS A WEAK TROPICAL STORM. TS 07W CONTINUES TO TRACK
POLEWARD ALONG THE PERIPHERY OF A SUBTROPICAL STEERING RIDGE TO THE
EAST.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS
WARNING.
B. TS 07W WILL CONTINUE TRACKING POLEWARD FOR THE NEXT 12 HOURS,
AND SUBSEQUENTLY TURN EASTWARD AS IT ROUNDS THE SUBTROPICAL STEERING
RIDGE AXIS. THE SYSTEM IS EXPECTED TO MAINTAIN INTENSITY PRIOR TO
LANDFALL IN HONSHU AS PASSAGE OVER WARM WATER AND SUPPORTIVE OUTFLOW
ALOFT CONTINUE TO OFFSET THE NEGATIVE INFLUENCES OF DRY AIR
ENTRAINMENT AND VWS. THE SYSTEM IS EXPECTED TO DISSIPATE BY TAU 48
DUE TO PASSAGE OVER LAND AND COOLER WATER TO THE EAST OF HONSHU.
NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT REGARDING THE
STEERING SCENARIO, LENDING HIGH CONFIDENCE TO THE CURRENT JTWC TRACK
FORECAST.//
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