Tropical Storm RAMMASUN Advisory Thu Jul 10

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 09W (NINE) WARNING
NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 09W (NINE), LOCATED APPROXIMATELY 372 NM
EAST-SOUTHEAST OF ANDERSEN AFB, HAS TRACKED NORTHWESTWARD AT 15
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS A COMPACT SYSTEM OBSCURING A RAPIDLY-
CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC). A 101152Z METOP-A
MICROWAVE IMAGE REVEALS THE BULK OF THE DEEP CONVECTION OVER THE
WESTERN SEMI-CIRCLE WITH TIGHTLY-CURVED BANDING WRAPPING INTO THE
LLCC. THE CURRENT POSITION IS BASED ON THE EIR ANIMATION AND ABOVE
MICROWAVE IMAGE WITH GOOD CONFIDENCE. THE INITIAL INTENSITY IS BASED
ON CONGRUENT DVORAK ESTIMATES FROM PGTW AND KNES. UPPER-LEVEL
ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH DUAL OUTFLOW, ONE
ENHANCED BY A TUTT CELL TO THE NORTHEAST AND A WESTWARD OUTFLOW
ENHANCED BY THE STRONG EASTERLY WINDS ALONG THE SOUTHERN PERIPHERY
OF THE RIDGE TO THE NORTH.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST
PHILOSOPHY.
   B. TD 09W IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF
THE SUBTROPICAL RIGDE (STR) ANCHORED TO THE NORTH. THE STR SYNOPTIC
PATTERN IS FORECAST TO REMAIN THROUGH THE FORECAST PERIOD WITH A
MIDLATUDE SHORTWAVE TROUGH FORECAST TO DEEPEN OVER THE EAST CHINA
SEA NEAR TAU 72. FAVORABLE CONDITIONS REMAIN THROUGHOUT THE FORECAST
PERIOD, ALLOWING THE SYSTEM TO GRADUALLY INTENSIFY.
   C. AFTER TAU 72, THE STR IS EXPECTED TO WEAKEN AS THE
AFOREMENTIONED MIDLATUDE TROUGH INFLUENCES THE STEERING ENVIRONMENT,
CAUSING THE DISTURBANCE TO RECURVE AFTER TAU 96. AVAILABLE MODEL
GUIDANCE IS IN TIGHT AGREEMENT; HOWEVER, NUMERICAL MODELS DEVELOP
THIS DISTURBANCE IN VARYING DEGREES WITH THE MOST AGGRESSIVE BEING
GFS. SINCE THIS IS A COMPACT SYSTEM, THE AVAILABLE GLOBAL MODELS
MIGHT NOT RESOLVE THIS SYSTEM CORRECTLY. DUE TO THIS UNCERTAINTY,
THERE IS OVERALL LOW CONFIDENCE TO THE OFFICIAL FORECAST.//
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