Tropical Storm FRANCISCO Advisory Tue Aug 06

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (FRANCISCO) WARNING
NR 15//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 09W (FRANCISCO), LOCATED APPROXIMATELY 287 NM
EAST-SOUTHEAST OF SASEBO, JAPAN, HAS TRACKED WEST-NORTHWESTWARD AT
14 KNOTS OVER THE PAST SIX HOURS. THERE IS HIGH CONFIDENCE IN THE
INITIAL POSITION BASED ON ANIMATED MULTISPECTRAL SATELLITE IMAGERY
THAT REVEALS A TIGHTLY WRAPPED SYSTEM WITH A PARTIALLY EXPOSED LOW
LEVEL CIRCULATION CENTER (LLCC) OCCASIONALLY OBSCURED BY FLARING
CONVECTION. THE MICROWAVE EYE SEEN IN THE 050526Z GMI 89GHZ IMAGE
FURTHER SUPPORTS THE POSITION. THE INITIAL INTENSITY OF 55 KTS IS
CONSISTENT WITH THE PGTW AND KNES DVORAK ESTIMATES OF T3.5 (55 KTS)
AND A 050115Z SATCON ESTIMATE OF 52 KNOTS. THE ENVIRONMENT IS
MARGINALLY FAVORABLE WITH LOW (5-10 KT) VERTICAL WIND SHEAR (VWS),
WARM (28-29 CELSIUS) SEA SURFACE TEMPERATURE (SST), AND FAIR RADIAL
OUTFLOW BEING OFFSET BY DRY AIR ENTRAINMENT FROM AN AREA OF UPPER-
LEVEL CONVERGENCE TO THE SOUTHWEST. TS 09W IS TRACKING ALONG THE
SOUTHWEST PERIPHERY OF A SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. IN THE NEAR TERM, TS 09W WILL CONTINUE ON A SIMILAR TRACK
ALONG THE SOUTHWEST PERIPHERY OF THE STR, MAKE LANDFALL OVER KYUSHU
AROUND TAU 12, AND PASS NEAR SASEBO JUST AFTER TAU 24. SECOND
LANDFALL WILL OCCUR NEAR BUSAN, KOREA AROUND TAU 30 AS THE CYCLONE
STARTS ROUNDING THE STR AXIS. SHORTLY AFTER TAU 48, TS 09W WILL HAVE
ROUNDED THE STR AXIS, BEGIN TRACKING NORTHEASTWARD OVER THE SEA OF
JAPAN, AND START EXTRATROPICAL TRANSITION (ETT) AS IT INTERACTS WITH
THE MID-LATITUDE BAROCLINIC ZONE. THE MARGINAL ENVIRONMENT SHOULD
INHIBIT FURTHER INTENSIFICATION BEFORE LANDFALL. AFTER LANDFALL, THE
SYSTEM WILL WEAKEN DUE TO LAND INTERACTION AS IT RAPIDLY TRACKS OVER
JAPAN AND KOREA. BY THE TIME TS 09W EMERGES INTO THE SEA OF JAPAN,
INTENSITY IS EXPECTED TO BE AROUND 35 KTS. MODEL GUIDANCE IS IN VERY
GOOD AGREEMENT THROUGH TAU 48, LENDING TO HIGH CONFIDENCE IN THE
JTWC TRACK FORECAST. AFTER TAU 48, TS 09W WILL TRACK EAST-
NORTHEASTWARD AND COMPLETE ETT AROUND TAU 72. DESPITE COOL SST AND
HIGH VWS, THE INTENSITY SHOULD ONLY DECREASE SLIGHTLY AS IT
TRANSITIONS INTO A COLD-CORE LOW. FOR THIS PORTION OF THE FORECAST,
SPREAD IN THE MODEL GUIDANCE INCREASES SLIGHTLY TO 150 NM, LENDING
TO FAIR CONFIDENCE IN THE EXTENDED TRACK FORECAST.//
NNNN
NNNN