Tropical Storm FRANCISCO Advisory Fri Aug 02

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (FRANCISCO)
WARNING NR 02//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 09W (FRANCISCO), LOCATED APPROXIMATELY 262 NM
SOUTH-SOUTHWEST OF MINAMI TORI SHIMA, HAS TRACKED NORTHWESTWARD AT
09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS A CONSOLIDATING SYSTEM WITH FLARING CONVECTION EAST OF
A PARTIALLY EXPOSED LLCC. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE PARTIALLY EXPOSED LLCC EVIDENT IN THE
MULTISPECTRAL IMAGERY LOOP AND A 012302Z ASCAT PASS INDICATING A
SLIGHTLY ELONGATED, BUT WELL DEFINED LLCC. THE INITIAL INTENSITY IS
ESTIMATED WITH HIGH CONFIDENCE AT 35 KNOTS, NUDGED HIGHER THAN
DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW OF T1.5 (25 KNOTS) IN
LIGHT OF THE AFOREMENTIONED ASCAT DATA, WHICH INDICATED A BROAD
SWATH OF 35 KNOT WINDS EXTENDING FROM THE NORTH TO SOUTHEAST OF THE
LLCC. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS IN AN AREA OF
MODERATE (20-25 KNOT) SOUTHWESTERLY VWS, WEAK SUBSIDENCE ASSOCIATED
WITH A NEARBY TUTT CELL, BEING OFFSET BY GOOD POLEWARD OUTFLOW TO
THE EAST OF THE LLCC. SSTS IN THE AREA ARE VERY WARM (30 DEGREES
CELSIUS) AND ALONG-TRACK OCEAN HEAT CONTENT IS HIGH. THE SYSTEM IS
TRACKING ALONG THE SOUTHWEST PERIPHERY OF A STR TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE PREVIOUS FORECAST PHILOSOPHY.
   B. TS 09W WILL TRACK TOWARDS THE NORTHWEST ON ITS CURRENT TRACK
THROUGH TAU 24, BEFORE FLATTENING SLIGHTLY TO A MORE WEST-
NORTHWESTWARD TRACK FROM TAU 24 THROUGH THE END OF THE FORECAST
PERIOD, UNDER THE INFLUENCE OF THE STR TO THE NORTH AND EAST. THE
AFOREMENTIONED MARGINAL CONDITIONS WILL PREVAIL OVER THE NEXT 24
HOURS ALLOWING FOR ONLY LIMITED, SLOW INTENSIFICATION. BEYOND TAU 36
HOWEVER, THE VWS GRADIENT WILL RELAX AND UPPER-LEVEL OUTFLOW
IMPROVES AS THE TUTT CELL AND STR TO THE NORTH INTERACT TO PRODUCE
DIVERGENT POLEWARD OUTFLOW, ALLOWING FOR MORE STEADY INTENSIFICATION
TO 80 KNOTS BY TAU 72.
   C. BEYOND TAU 72, 09W WILL CONTINUE ON A WEST-NORTHWESTWARD TRACK
UNDER THE STEERING INFLUENCE OF THE STR, GENERALLY TOWARDS KYUSHU,
JAPAN. ENVIRONMENTAL CONDITIONS WILL CONTINUE TO BE FAVORABLE WITH
DIVERGENT POLEWARD OUTFLOW INDUCED BY THE INTERACTION OF THE TUTT
CELL THAT WILL MOVE WESTWARD IN ADVANCE OF THE SYSTEM, AND THE BROAD
STR TO THE WEST, WARM SSTS ASSOCIATED WITH THE KUROSHIO CURRENT, AND
LOW TO MODERATE VWS. THE PEAK INTENSITY IN THE FORECAST IS 85 KNOTS
BUT A HIGHER PEAK INTENSITY IS CERTAINLY POSSIBLE BETWEEN TAUS 96
AND 120 JUST PRIOR TO LANDFALL ON THE KYUSHU COAST. AFTER LANDFALL,
TERRAIN INTERACTION, INCREASING VWS AND DECREASING SSTS WILL COMBINE
TO ERODE TS 09W TO 60 KNOTS BY TAU 120 TO THE WEST OF SASEBO.
DYNAMIC MODELS ARE IN STRONG AGREEMENT THROUGH TAU 72, WITH SOME
INCREASING UNCERTAINTY THEREAFTER. SIGNIFICANT DIVERGENCE IN THE
MODELS BECOMES EVIDENT BY TAU 120 WITH NAVGEM WELL TO THE RIGHT OF
ALL MODELS, TAKING THE SYSTEM INTO THE SEA OF JAPAN, WITH ECMWF
450NM TOO DISTANT, TAKING THE SYSTEM WEST OF CHEJU DO AND INTO THE
YELLOW SEA. GIVEN THE INCREASED CONFIDENCE IN THE INITIAL POSITION
AND OVERALL STRONG MODEL AGREEMENT THROUGH TAU 72, THERE IS OVERALL
HIGH CONFIDENCE IN THE JTWC TRACK.//
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