Tropical Storm FITOW Advisory Thu Oct 03

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (FITOW) WARNING NR
12//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 22W (FITOW), LOCATED APPROXIMATELY 401 NM SOUTH-
SOUTHEAST OF KADENA AB, HAS TRACKED NORTHWARD AT 05 KNOTS OVER THE
PAST SIX HOURS ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
CONTINUES TO REVEAL A RAGGED LOW-LEVEL CIRCULATION CENTER (LLCC)
WITH BROKEN DEEP CONVECTIVE BANDING WRAPPING INTO THE LLCC. THE
CURRENT POSITION IS BASED ON A 022129Z SSMIS MICROWAVE SATELLITE
IMAGE AND RECENT POSITION FIXES FROM PGTW AND KNES WITH HIGH
CONFIDENCE. THE CURRENT INTENSITY OF 60 KNOTS IS ON THE HIGH END OF
DVORAK ESTIMATES TO REFLECT THE SUSTAINED CONVECTIVE SIGNATURE AND
IS CONSISTENT WITH RECENT DVORAK INTENSITY ESTIMATES FROM PGTW,
RJTD, AND KNES. UPPER-LEVEL ANALYSIS AND RECENT WATER VAPOR IMAGERY
INDICATE THE SYSTEM IS IN A FAVORABLE ENVIRONMENT WITH LOW TO
MODERATE (05 TO 15 KNOT) VERTICAL WIND SHEAR (VWS) AND STRONG RADIAL
OUTFLOW. TS 22W IS TRACKING ALONG THE WESTERN PERIPHERY OF THE NEAR
EQUATORIAL RIDGE TO THE EAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 22W IS EXPECTED TO CONTINUE TRACKING POLEWARD OVER THE NEXT
36 HOURS. AFTER TAU 36, A SUBTROPICAL RIDGE (STR) ANCHORED EAST OF
JAPAN IS FORECAST TO BUILD AND EXTEND WESTWARD AND INFLUENCE THE
STEERING OF THE CYCLONE. THIS STR WILL PUSH THE SYSTEM ON A MORE
NORTHWESTWARD TRACK. FAVORABLE ENVIRONMENTAL CONDITIONS, INCLUDING
LOW VWS, ENHANCED UPPER-LEVEL OUTFLOW, AND WARM (27 TO 28 DEGREES
CELSIUS) ALONG-TRACK SEA SURFACE TEMPERATURES, WILL ALLOW THE SYSTEM
TO INTENSIFY THROUGH TAU 72. AVAILABLE MODEL GUIDANCE IS IN GOOD
AGREEMENT WITH THE POLEWARD TRACK THROUGH TAU 36 AND DIVERGES
THEREAFTER. BASED ON THE SPREAD IN GUIDANCE AFTER TAU 36, THERE IS
LOW CONFIDENCE IN THE FORECAST TRACK THROUGH TAU 72.
   C. AFTER TAU 72, TS 22W WILL CONTINUE TRACKING NORTHWESTWARD
ALONG THE PERIPHERY OF THE STR. THE INTENSITY IS EXPECTED TO SLOWLY
DECREASE AS COLD AIR ENTRAINMENT STRENGTHENS. FURTHERMORE, VWS IS
ALSO EXPECTED TO INCREASE AS THE SYSTEM TRACKS NORTHWESTWARD. TS
FITOW IS EXPECTED TO MAKE LANDFALL SOUTH OF SHANGHAI BY TAU 72 AND
BEGIN DISSIPATION DUE TO FRICTIONAL EFFECTS. NUMERICAL MODEL
GUIDANCE CONTINUES TO DIVERGE AFTER TAU 72. GIVEN THE CONTINUED
SPREAD IN THE MODELS AND THE UNCERTAINTY IN HOW MUCH THE STR IS
EXPECTED TO BUILD, THERE IS LOW CONFIDENCE IN THE TRACK FORECAST.//
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