Tropical Storm WIPHA Advisory sáb, 12-10

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (WIPHA) WARNING NR
07//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 25W (WIPHA), LOCATED APPROXIMATELY 363 NM WEST-
NORTHWEST OF NAVSTA GUAM, HAS TRACKED NORTHWESTWARD AT 09
KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL
SATELLITE IMAGERY SHOWS DEEP CONVECTION CONTINUING TO CONSOLIDATE
AROUND THE LOW-LEVEL CIRCULATION CENTER (LLCC). A 112223Z SSMI-S
MICROWAVE IMAGE DEPICTS A BROAD BAND OF DEEP CONVECTION WRAPPING
INTO THE LLCC FROM THE SOUTHWEST AND DEEP CONVECTION IS BEGINNING TO
WRAP AROUND THE NORTHERN SEMI-CIRCLE WITH SOME FRAGMENTATION. THE
CURRENT POSITION IS BASED ON AN EXTRAPOLATION FROM THE
AFOREMENTIONED MICROWAVE IMAGE AND HAS BEEN VERIFIED BY A MORE
RECENT 120006Z AMSU-B PASS. THE CURRENT INTENSITY IS SLIGHTLY HIGHER
THAN DVORAK ESTIMATES FROM ALL REPORTING AGENCIES BASED ON THE
IMPROVING CORE STRUCTURE. UPPER-LEVEL ANALYSIS INDICATES FAVORABLE
ENVIRONMENTAL CONDITIONS REMAIN IN PLACE, WITH LOW (5 TO 10 KTS)
NORTHEASTERLY VERTICAL WIND SHEAR, AND STRONG RADIAL OUTFLOW
OBSERVED IN ANIMATED WATER VAPOR IMAGERY. POLEWARD OUTFLOW IS ALSO
BEING ENHANCED BY A TUTT CELL TO THE NORTHEAST. FURTHER IMPROVEMENT
IS EXPECTED AS A WEAK TUTT CELL IS COMPLETING ITS TRANSITION OVER
THE NORTHERN SEMICIRCLE OF THE SYSTEM. SOME UPPER-LEVEL CONVERGENCE
CAN STILL BE SEEN OVER THE NORTHWESTERN QUADRANT BUT OVERALL OUTFLOW
IS IMPROVING. THE CURRENT POSITION WIND RADII HAVE BEEN ADJUSTED
BASED ON A TIMELY 120006Z ASCAT PASS. TS 25W IS TRACKING ALONG THE
SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR)
TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST TRACK PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 25W WILL TURN POLEWARD AS IT PROGRESSES ALONG THE
SOUTHWESTERN PERIPHERY OF THE STEERING RIDGE OVER THE NEXT 72 HOURS.
FAVORABLE ENVIRONMENTAL CONDITIONS WILL DRIVE CONTINUED
INTENSIFICATION TO A PEAK INTENSITY OF 110 KNOTS BY TAU 48.
INTENSITY GUIDANCE SUGGESTS A HIGH LIKELIHOOD OF RAPID
INTENSIFICATION WITHIN THE NEXT 24 HOURS AND FORECAST INTENSITY
REFLECTS THIS WITH A 30-KNOT INCREASE FROM 60 KNOTS UP TO 90 KNOTS
BY TAU 24. DURING TAUS 36-72, TS 25W SHOULD CONTINUE TO INTENSIFY AT
A CLIMATOLOGICAL RATE BUT THE POSSIBILITY OF FURTHER RAPID
INTENSIFICATION STILL EXISTS. DYNAMICAL TRACK GUIDANCE CONTINUES TO
BE IN GOOD AGREEMENT, AND THE CURRENT FORECAST LIES CLOSE TO THE
MULTI-MODEL CONSENSUS. BASED ON THE STRAIGHTFORWARD STEERING
ENVIRONMENT AND AGREEMENT AMONG THE NUMERICAL MODELS, FORECAST TRACK
CONFIDENCE DURING THIS PERIOD IS HIGH.
   C. IN THE EXTENDED PERIOD, TS 25W WILL ROUND THE STEERING RIDGE
AXIS AND ACCELERATE TO THE NORTHEAST AHEAD OF A MIDLATITUDE TROUGH
APPROACHING FROM THE NORTHWEST. INCREASING VERTICAL WIND SHEAR AND
LOWER ALONG-TRACK SEA SURFACE TEMPERATURES WILL INDUCE STEADY
WEAKENING. TS 25W SHOULD BEGIN TO INTERACT WITH THE BAROCLINIC
TROUGH BEGINNING AROUND TAU 96, ACCELERATE RAPIDLY INTO THE MID-
LATITUDE WESTERLIES THEREAFTER, AND COMPLETE A RAPID EXTRATROPICAL
TRANSITION BY TAU 120. POST-RECURVATURE TRACK SPEEDS AMONG MODEL
SOLUTIONS CONTINUE TO VARY SIGNIFICANTLY. THE JTWC FORECAST TRACK IS
POSITIONED SLIGHTLY FASTER THAN THE MULTI-MODEL CONSENSUS IN THE
EXTENDED PERIOD TO OFFSET THE SLOWER TRACKERS. HOWEVER, DUE TO
UNCERTAINTY IN THE POST-RECURVATURE TRACK SPEEDS, CONFIDENCE IN THE
EXTENDED TRACK FORECAST IS LOW.//
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