Tropical Storm CHAN-HOM Advisory Fri Jul 03

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (CHAN-HOM) WARNING
NR 13//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 09W (CHAN-HOM), LOCATED APPROXIMATELY 277 NM
SOUTHEAST OF ANDERSEN AFB, GUAM HAS TRACKED NORTHEASTWARD AT 04
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A BROAD AREA OF POORLY ORGANIZED CONVECTION SHEARED
WELL TO THE SOUTHWEST OF THE LOW LEVEL CIRCULATION CENTER (LLCC).
THE INITIAL POSIT IS EXTRAPOLATED FROM AN 031101Z ASCAT BULLSEYE
WITH GOOD CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 45 KNOTS
BASED ON DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW AND RJTD,
WHICH ARE SUPPORTED BY THE AFOREMENTIONED ASCAT PASS. TS 09W HAS
DISPLAYED DIRECT CYCLONE INTERACTION (DCI) WITH A REMANT CIRCULATION
TO THE NORTHEAST RESULTING IN A NORTHEASTERLY TRACK OVER THE PAST 12
HOURS. THE REMNANT LLCC, HOWEVER, HAS NO SURFACE REFLECTION IN TWO
RECENT SCATTEROMETRY PASSES, THEREFORE 09W REMAINS THE
DOMINANT CIRCULATION. AN AREA OF TROUGHING TO THE NORTH OF TS 09W IS
STILL IN PLACE PRODUCING INCREASED VERTICAL WIND SHEAR(VWS),
SUBSIDENCE AND INCREASED CONVERGENCE ALOFT. THESE IMPACTS ARE
SUPPRESSING CONVECTION.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 09W WILL CONTINUE TO DRIFT NORTH TO NORTHEASTWARD OVER THE
NEXT 12 HOURS WHILE TS 09W INTERACTS WITH THE REMNANT VORTEX IN A
WEAK STEERING ENVIRONMENT. AFTER THIS TIME, TS CHAN-HOM WILL TURN
BACK TO A NORTHWESTWARD TRACK AS THE TUTT CELL RETROGRADES TO THE
EAST AND THE REMNANT VORTEX DISSIPATES. THE SYSTEM SHOULD GRADUALLY
BEGIN TO REORGANIZE AS THE EFFECTS OF THE UPPER LEVEL TROUGHING
SUBSIDES, RESULTING IN LOWER VWS AND IMPROVING OUTFLOW. THIS
INTENSIFICATION WILL CONTINUE THROUGHOUT THE REMAINDER OF THIS
FORECAST PERIOD. DYNAMICAL MODELS ARE NOT HANDLING THIS COMPLEX
CYCLONE INTERACTION AND TUTT CELL IMPACTS. THE OFFICIAL FORECAST IS
SLOWER THAN CONSENSUS, WITH POOR CONFIDENCE.
   C. IN THE EXTENDED TAUS, TS CHAN-HOM WILL CONTINUE TO TRACK
NORTHWESTWARD AND FURTHER INTENSIFY AS VWS AND OUTFLOW REMAIN
FAVORABLE. DYNAMIC MODEL GUIDANCE DIVERGES GREATLY AROUND TAU 96
ASSOCIATED WITH THE TIMING OF EVENTUAL RECURVATURE. THEREFORE, THERE
IS LOW CONFIDENCE IN THIS PORTION OF THE FORECAST.//
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