Tropical Storm WIPHA Advisory Sun Oct 13

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (WIPHA) WARNING NR 11//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 25W (WIPHA), LOCATED APPROXIMATELY 441 NM SOUTH-
SOUTHWEST OF IWO TO, HAS TRACKED NORTHWESTWARD AT 08 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
DEPICTS A DEEPENING SYSTEM, GROWING IN SIZE AND SYMMETRY, WITH
TIGHTLY CURVED BANDING WRAPPING INTO A LOW-LEVEL CIRCULATION CENTER
(LLCC). A 121403Z OSCAT PASS REVEALS THE LARGE EXTENT OF WIND FIELD
AROUND 25W. A 122101Z SSMIS 91 GHZ MICROWAVE IMAGE REVEALS THE
IMPROVING CONVECTION OF THE CENTRAL CORE AND THE FORMATION OF A
MICROWAVE EYE.  THE CURRENT POSITION IS BASED ON THE MSI LOOP AND
AFOREMENTIONED MICROWAVE IMAGE WITH EXCELLENT CONFIDENCE. THE
CURRENT INTENSITY HAS BEEN INCREASED TO 90 KNOTS BASED ON THE PGTW
DVORAK INTENSITY AND CIMSS SATCON ESTIMATES OF 90 KNOTS, AND
ACCOUNTING FOR THE CLEAR IMPROVEMENT IN OF CONVECTIVE ORGANIZATION.
UPPER-LEVEL ANALYSIS INDICATES TY 25W IS IN A VERY FAVORABLE
ENVIRONMENT ABOUT FIVE DEGREES SOUTH OF THE SUBTROPICAL RIDGE (STR)
AXIS, WITH LOW (5 TO 10 KTS) NORTHEASTERLY VERTICAL WIND SHEAR
(VWS), AND ROBUST RADIAL OUTFLOW OBSERVED IN ANIMATED WATER VAPOR
IMAGERY. POLEWARD OUTFLOW CONTINUES TO BE ENHANCED BY A TUTT CELL TO
THE NORTHEAST. TY 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, HOWEVER WIND RADII HAVE BEEN
ADJUSTED UPWARD BASED ON OSCAT IMAGERY TO REFLECT THE LARGE STORM
SIZE.
   B. TY 25W WILL CONTINUE TO TRACK TO THE NORTHWEST AS IT
PROGRESSES ALONG THE SOUTHWESTERN PERIPHERY OF THE STEERING RIDGE
OVER THE NEXT 48 HOURS. FAVORABLE ENVIRONMENTAL CONDITIONS WILL
ALLOW THE SYSTEM TO REACH A PEAK INTENSITY OF 115 KNOTS BY TAU 36,
AS IT BEGINS TO ROUND THE STR. BY TAU 48, THE SYSTEM WILL TURN TO
THE NORTHEAST AND WILL BEGIN A SPEEDY EXTRATROPICAL TRANSITION (ETT)
PRIOR TO TAU 72, AS THE SYSTEM IS PASSING JUST TO THE EAST OF JAPAN.
DYNAMIC MODEL GUIDANCE CONTINUES TO BE IN TIGHT AGREEMENT, NOW
THROUGH TAU 72 AND THE CURRENT FORECAST TRACK LIES JUST INSIDE OF
THE MULTI-MODEL CONSENSUS. BASED ON THE STRONG AGREEMENT AMONG THE
OBJECTIVE AIDS THE CONFIDENCE IN THIS PORTION OF THE FORECAST TRACK
IS HIGH.
   C. IN THE EXTENDED TAUS, TY 25W WILL COMPLETE ETT PRIOR TO TAU
96.  DYNAMIC MODEL GUIDANCE THROUGH THIS PORTION OF THE FORECAST
TRACK IS IN FAIRLY GOOD AGREEMENT IN TRACK BUT HAVE SOME DIFFERENCES
IN ALONG TRACK TRANSLATIONAL SPEEDS. DUE TO THIS, THE JTWC FORECAST
IS LAID SLIGHTLY FASTER THAN THE MULTI-MODEL CONSENSUS WITH LOW
CONFIDENCE.//
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