Subject: Pacific-NW: Subj/prognostic Reasoning For Tropical Storm 01w Warning Nr 06//

From: SIU Weather Processor <[email-masked]>
Date: Mon, 14 Jan 2008 08:52:12 -0600

WDPN31 PGTW 141500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W WARNING NR 06//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TROPICAL STORM (TS) 01W (NONAME) HAS MAINTAINED 35 KT
INTENSITY OVER THE CENTRAL SOUTH CHINA SEA AS A RESULT OF
GOOD UPPER LEVEL POLEWARD OUTFLOW AND ADEQUATEOCEAN HEAT
CONTENT VALUES. DRY AIR ENTRAINMENT IN THE LOW TO MID LEVELS
IS EVIDENT IN RECENT MICROWAVE AND ENHANCED INFRARED SATELLITE
IMAGERY.
   B. THE WARNING POSITION IS BASED ON ANIMATED MULTISPECTRAL
IMAGERY AND A 141115Z SSMI/S MICROWAVE PASS. THE INITIAL
INTENSITY IS BASED ON DVORAK ESTIMATES OF 2.5 FROM PGTW AND 3.0
FROM KNES; HOWEVER, CONVECTION HAS RECENTLY DIMINISHED NEAR THE LOW
LEVEL CIRCULATION CENTER (LLCC). THE STORM CONTINUES TO BE STEERED
SOUTHWESTWARD ON THE SOUTHEASTERN PERIPHERY OF A 700 MB RIDGE
EXTENDING FROM THAILAND TO VIETNAM. VERTICAL WIND SHEAR VALUES
REMAIN LIGHT TO MODERATE OVER THE STORM.
3. FORECAST REASONING
   A. FOR THE PAST TWO FORECASTS, THE TAU 36 AND 48 POSITIONS ARE
FURTHER SOUTH THAN THE PREVIOUS FORECASTS. THIS REFLECTS FASTER
OBSERVED TRACK SPEEDS OVER THE PAST 12 HOURS THAN WERE PREVIOUSLY
PREDICTED.
   B. THE SUBTROPICAL RIDGE WILL CONTINUE TO STEER THE SYSTEM
SOUTHWESTWARD INTO HIGHER VERTICAL WIND SHEAR VALUES AND LOW OCEAN
HEAT CONTENT. POLEWARD OUTFLOW WILL ALSO DIMINISH AS THE SYSTEM
MOVES SOUTH OF THE RIDGE AXIS. SUBSEQUENTLY, BY TAU 36 THE STORM IS
EXPECTED TO HAVE DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE. THE
OBJECTIVE AIDS REMAIN IN GOOD AGREEMENT WITH THE CONTINUED EXCEPTION
OF WBAR.
FORECAST TEAM: BRAVO//

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