Subject: Pacific-NW: Subj/prognostic Reasoning For Tropical Depression 18w Warning Nr 06//

From: SIU Weather Processor <[email-masked]>
Date: Sat, 13 Nov 2010 19:50:08 -0600

WDPN31 PGTW 140300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 18W WARNING NR 06//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
A. TROPICAL DEPRESSION (TD) 18W, LOCATED APPROXIMATELY 85 NM SSE OF
DA NANG, HAS TRACKED WEST-NORTHWESTWARD AT 08 KNOTS OVER THE PAST
SIX HOURS. ANIMATED WATER VAPOR ANIMATION SHOWS THE CONVECTION
ASSOCIATED WITH THE SYSTEM HAS WEAKENED AND FURTHER DISORGANIZED.
HOWEVER, POLEWARD OUTFLOW REMAINS SOLID. THERE IS ALSO EVIDENCE OF
INCREASING VERTICAL WIND SHEAR (VWS) ALONG THE NORTHWEST FLANK OF
THE SYSTEM. THE CURRENT POSITION, INDICATING THE SYSTEM HAS JUST
MADE LANDFALL OVER THE VIETNAM COAST, IS SUPPORTED BY A 132235Z
SSMI/S MICROWAVE IMAGE. TD 18W HAS MAINTAINED ITS INTENSITY OF 25
KNOTS BASED ON 132330Z PGTW DVORAK FIX. TD 18W IS TRACKING SLOWLY
WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE LOW- TO MID-
LEVEL SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING:
    A. THERE IS NO CHANGE TO THE PREVIOUS FORECAST REASONING.
    B. TD 18W AND WILL CONTINUE TO TRACK WEST-NORTHWESTWARD ALONG
THE SOUTHERN PERIPHERY OF THE AFOREMENTIONED STR. THIS TRAJECTORY
WILL BRING THE SYSTEM DIRECTLY UNDER SIGNIFICANTLY HIGHER VWS
ASSOCIATED WITH THE LONG WAVE TROUGH DIGGING INTO SOUTHEAST CHINA.
THIS, COUPLED WITH THE EFFECTS OF THE RUGGED TERRAIN, WILL ENSURE
RAPID DISSIPATION OF THE SYSTEM WITHIN 12 HOURS.//

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