Tropical Storm MITAG Advisory Tue Oct 01

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 19W (MITAG) WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 19W (MITAG), LOCATED APPROXIMATELY 161 NM
SOUTH-SOUTHEAST OF TAIPEI, TAIWAN, HAS TRACKED NORTHWARD AT 11 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) REVEALS A SMALL RAGGED EYE WITH DISTINCT RAIN BANDS. THERE IS
HIGH CONFIDENCE IN THE INITIAL POSITION BASED OFF OF MSI. THE INITIAL
INTENSITY IS CONSISTENT WITH MULTI-AGENCY DVORAK INTENSITY ESTIMATES
OF T4.5 (77 KTS). LOW (5-10 KT) VERTICAL WIND SHEAR (VWS), EXCELLENT
EQUATORWARD AND POLEWARD OUTFLOW, AND WARM (27-28 CELSIUS) SEA
SURFACE TEMPERATURE (SST) IS BEING PARTIALLY OFFSET BY DRY AIR
ENTRAINMENT AS TY 19W GRAZES TAIWAN. THEREFORE, THE ENVIRONMENT IS
SLIGHTLY FAVORABLE FOR INTENSIFICATION. TY 19W IS TRACKING AROUND THE
SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. THROUGH TAU 48, TY 19W WILL CREST THE STR AXIS AND GRADUALLY
TURN ONTO A NORTHEASTWARD TRACK. THE ENVIRONMENT SHOULD MAINTAIN
FAVORABLE CONDITIONS THROUGH TAU 12, HOWEVER, FRICTION DUE TO LAND
INTERACTION WITH TAIWAN SHOULD LIMIT INTENSIFICATION. AFTER TAU 12,
LAND INTERACTION WITH COASTAL CHINA, COOL SST, AND HIGH VWS SHOULD
GRADUALLY WEAKEN THE SYSTEM. THERE IS HIGH UNCERTAINTY IN THE
NEAR-TERM INTENSITY FORECAST BECAUSE OF THE PROXIMITY OF THE TRACK TO
CHINA AND TAIWAN. DYNAMIC MODEL GUIDANCE IS IN STRONG OVERALL
AGREEMENT ON THE TIMING AND LOCATION OF RE-CURVATURE BUT ALONG-TRACK
SPEED DIFFERENCES INCREASE AFTER TAU 48, LEADING TO FAIR OVERALL
AGREEMENT IN THIS PORTION OF THE TRACK FORECAST.
   C. AFTER TAU 72, TY 19W WILL BECOME EMBEDDED IN THE MID-LATITUDE
WESTERLIES AND START EXTRATROPICAL TRANSITION (ETT). PRIOR TO TAU
120, TY 19W WILL HAVE COMPLETELY TRANSITIONED INTO A COLD-CORE LOW AS
IT APPROACHES JAPAN. THE ALONG-TRACK AND CROSS-TRACK UNCERTAINTY
REMAINS HIGH (360 NM) AT TAU 120 DUE TO TIMING OF CAPTURE IN THE
WESTERLIES. THERE IS POOR CONFIDENCE IN THE EXTENDED TRACK FORECAST.//
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