Tropical Storm KIROGI Advisory Mon Aug 06

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W (THIRTEEN) WARNING
NR 08//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 13W (THIRTEEN), LOCATED APPROXIMATELY 550 NM
NORTH-NORTHWEST OF WAKE ISLAND, HAS TRACKED NORTH-NORTHWESTWARD AT
13 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY AND A 061101Z AMSU-B 89 GHZ MICROWAVE IMAGE SHOW
THE DEEPEST CONVECTION REMAINS ALONG THE NORTHERN HALF OF THE SYSTEM
WITH FLARING CENTRAL CONVECTION OVER THE PARTIALLY EXPOSED LOW-
LEVEL CIRCULATION CENTER (LLCC). THE CURRENT POSITION IS BASED ON
THE ABOVE MENTIONED IMAGERY WITH HIGH CONFIDENCE. THE CURRENT
INTENSITY IS BASED ON PERSISTENCE FROM A 060130Z OSCAT PASS
INDICATING 40-45 KNOTS OVER THE NORTHEASTERN QUADRANT OF THE LLCC.
UPPER-LEVEL ANALYSIS INDICATES THE SYSTEM CURRENTLY RESIDES IN
BETWEEN THE NEAR EQUATORIAL RIDGE TO THE SOUTHEAST AND THE
SUBTROPICAL RIDGE TO THE NORTH WITH A MID-LATITUDE TROUGH PULLING
OUT OF THE AREA TO THE NORTH-NORTHEAST. THIS COMPLEX UPPER-LEVEL
ENVIRONMENT IS PROVIDING FOR MODERATE TO STRONG (20-30 KNOTS)
VERTICAL WIND SHEAR (VWS). ANIMATED WATER VAPOR IMAGERY SHOWS
OUTFLOW INTO THE TROPICAL UPPER TROPOSPHERIC TROUGH CELL TO THE
EAST AND NORTHWARD INTO THE PROPAGATING TROUGH BUT NO EVIDENCE OF
EQUATORWARD OUTFLOW.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE
PREVIOUS PROGNOSTIC REASONING BULLETIN.
   B. TS 13W IS EXPECTED TO COME UNDER THE STEERING INFLUENCE OF
THE SOUTHWESTERN PERIPHERY OF THE BUILDING SUBTROPICAL RIDGE DURING
THE REMAINDER OF THE FORECAST PERIOD. INTENSITY SHOULD REMAIN
CONSTANT AS VWS SHOULD DECREASE AND SEA SURFACE TEMPERATURES WILL
REMAIN NEAR 26 DEGREES CELSIUS. HOWEVER, AS THE SYSTEM GAINS
POLEWARD LATITUDE THE AIR MASS WILL BECOME DRIER AND ENTRAIN INTO
THE LLCC HINDERING ANY FURTHER INTENSIFICATION.
   C. BY TAU 96 TS 13W WILL HAVE DISSIPATED OVER WATER AND MAY EVEN
TRANSITION INTO A COLD-CORE SYSTEM BEFORE THIS TIME, AS INDICATED
BY PHASE SPACE MODEL OUTPUT. THERE IS HIGH CONFIDENCE IN THE
FORECAST TRACK DUE TO TIGHTLY GROUPED OBJECTIVE AIDS.//
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