Tropical Storm SARIKA Advisory śro., 12.10.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 24W (TWENTY-FOUR)
WARNING NR 01//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 24W (TWENTY-FOUR), LOCATED APPROXIMATELY 526
NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT
11 KNOTS OVER THE PAST SIX HOURS.  ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS FRAGMENTED FORMATIVE BANDS SLOWLY
CONSOLIDATING AROUND AN OBSCURED AND ILL-DEFINED LOW LEVEL
CIRCULATION CENTER. A TUTT CELL TO THE NORTHWEST IS ENHANCING
POLEWARD OUTFLOW AND PROVIDING VENTILATION TO THE CONVECTION. THE
INITIAL POSITION IS BASED ON THE EIR LOOP AND LINED UP WITH A RAGGED
LOW REFLECTIVITY CIRCULATION FEATURE IN THE 120915Z AMSU-B MICROWAVE
IMAGE WITH FAIR CONFIDENCE. THE INITIAL INTENSITY OF 25 KNOTS IS
BASED ON AN OVERALL ASSESSMENT OF AGENCY DVORAK ESTIMATES AND A
RECENT ASCAT PASS. THE SYSTEM IS IN A VERY FAVORABLE ENVIRONMENT
WITH LOW VERTICAL WIND SHEAR, GOOD DUAL OUTFLOW, AND VERY WARM SEA
SURFACE TEMPERATURES. THE CYCLONE IS TRACKING ALONG THE SOUTHERN
PERIPHERY OF A LOW- TO MID-LEVEL REFLECTION OF THE SUBTROPICAL RIDGE
(STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL WARNING AND SETS THE FORECAST PHILOSOPHY
FOR THIS SYSTEM.
   B. TD 24W IS EXPECTED TO TRACK WEST-NORTHWESTWARD THROUGHOUT THE
FORECAST: SLOWLY IN THE NEAR TERM, THEN FASTER AS IT DEEPENS. THE
AFOREMENTIONED FAVORABLE CONDITIONS WILL PERSIST AND PROMOTE GRADUAL
INTENSIFICATION, REACHING 75 KNOTS BY TAU 72.
   C. IN THE EXTENDED TAUS, TD 24W WILL DRAG ACROSS CENTRAL LUZON,
PHILIPPINES, THEN EXIT INTO THE SOUTH CHINA SEA (SCS). THE SYSTEM
WILL MOMENTARILY WEAKEN TO 60 KNOTS DUE TO LAND INTERACTION BUT
SHOULD RE-INTENSIFY AS FAVORABLE CONDITIONS EXTEND INTO THE SCS,
REACHING 80 KNOTS BY TAU 120. NUMERIC MODEL GUIDANCE IS UNIFIED ON
THE GENERAL WEST-NORTHWESTWARD TRAJECTORY OF THE CYCLONE; HOWEVER,
THERE IS A 240NM SPREAD IN THE MODEL ENVELOPE. THIS, IN ADDITION TO
THE VARIABILITY IN THE NEAR-TERM STORM MOTION, LENDS LOW CONFIDENCE
IN THE INITIAL JTWC TRACK FORECAST.//
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