Tropical Storm GUCHOL Advisory Wed Jun 13

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (GUCHOL) WARNING NR
09//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 05W (GUCHOL), LOCATED APPROXIMATELY 135 NM
EAST OF YAP, HAS TRACKED WESTWARD AT 07 KNOTS OVER THE PAST SIX
HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS CONVECTIVE BANDING
WRAPPING INTO A LOW LEVEL CIRCULATION CENTER (LLCC). A 122321Z SSMIS
MICROWAVE IMAGE DEPICTS IMPROVED CONVECTIVE ORGANIZATION FROM WHICH
THE INITIAL POSITION WAS BASED WITH GOOD CONFIDENCE. THE INITIAL
INTENSITY WAS BASED ON THE KNES AND PGTW DVORAK ESTIMATES OF 35
KNOTS. WATER VAPOR IMAGERY SHOWS IMPROVED RADIAL OUTFLOW WITH A
SLIGHT PULL INTO A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL TO
THE NORTH. THE TOTAL PRECIPITABLE WATER PRODUCT INDICATES A
SUBSIDENT, DRY REGION TO THE NORTHWEST IS WEAKENING. SEA SURFACE
TEMPERATURES (28-29 DEGREES CELSIUS) ARE FAVORABLE FOR DEVELOPMENT.
TS 05W IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A MID-
LEVEL SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 05W IS EXPECTED TO CONTINUE TRACKING ALONG THE SOUTHERN
PERIPHERY OF THE STR. THE SYSTEM SHOULD BEGIN TO TURN WEST-
NORTHWESTWARD TO NORTHWESTWARD THROUGH TAU 72, AS THE STR WEAKENS
AHEAD OF AN APPROACHING MID-LATITUDE TROUGH, CURRENTLY DIGGING SOUTH
OF CHINA. MODEL GUIDANCE IS IN TIGHT AGREEMENT TROUGH TAU 72;
THEREFORE, THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK.
   C. AFTER TAU 72, TS 05W IS FORECAST TO ROUND THE SOUTHWESTERN
PERIPHERY OF THE WEAKENING STR AND TURN MORE POLEWARD. IN THE
EXTENDED FORECAST, MODEL GUIDANCE SPREADS WITH NOGAPS AND GFDN
MAKING THE FASTEST TURN POLEWARD SOUTH OF OKINAWA, JAPAN. UKMO AND
GFS MAINTAIN A MORE NORTHWESTWARD TRACK AND SLOWLY TURN THE SYSTEM
POLEWARD. THERE IS LOW CONFIDENCE IN THE RECURVATURE TIMING AND
POSITION DUE TO THE MODEL SPREAD IN THE EXTENDED FORECAST. HOWEVER,
THE JTWC FORECAST FAVORS A RECURVATURE SCENARIO BASED ON THE
DEEPENING MID-LATITUDE TROUGH. TS GUCHOL SHOULD CONTINUE TO STEADILY
INTENSIFY AS IT TRACKS OVER WARM WATER AND AS OUTFLOW INCREASES INTO
THE MID-LATITUDE TROUGH. THIS INTENSITY FORECAST IS IN AGREEMENT
WITH INTENSITY MODEL GUIDANCE.//
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