Subject: Pacific-NW: Subj/prognostic Reasoning For Tropical Storm 13w Warning Nr 14//

From: SIU Weather Processor <[email-masked]>
Date: Thu, 23 Sep 2010 09:31:04 -0500

WDPN32 PGTW 231500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W WARNING NR 14//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TROPICAL STORM (TS) 13W (MALAKAS), LOCATED APPROXIMATELY 170
NM SOUTH OF IWO TO, JAPAN, HAS TRACKED NORTHWARD AT 12 KNOTS
OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS A
BANDING EYE FEATURE WITH CONVECTION RE-BUILDING OVER THE SYSTEM
CENTER. A 231021Z 37 GHZ SSMIS PASS AND A 231032Z 37 GHZ TRMM PASS
DEPICT A FORMATIVE MICROWAVE EYE AND CONFIRM THE CURRENT POSITION
WITH FAIR CONFIDENCE. THE CURRENT INTENSITY REMAINS AT 60 KNOTS
BASED ON DVORAK ESTIMATES RANGING FROM 55 TO 65 KNOTS FROM PGTW,
KNES, AND RJTD. UPPER LEVEL ANALYSIS INDICATES THE SUBSIDENCE
PREVIOUSLY HINDERING CONVECTION ALONG THE WESTERN PERIPHERY OF THE
SYSTEM HAS DECREASED ALLOWING FOR GOOD RADIAL OUTFLOW. TS 13W IS
CURRENTLY TRACKING ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL
STEERING RIDGE ANCHORED OVER THE NORTHERN PACIFIC.
3. FORECAST REASONING.
   A. THE FORECAST REASONING HAS NOT CHANGED SINCE THE PREVIOUS
PROGNOSTIC REASONING BULLETIN.
   B. TS 13W IS FORECAST TO CONTINUE TRACKING POLEWARD AS IT ROUNDS
THE RIDGE AXIS AND BEGINS TO INTERACT WITH THE STRONG BAROCLINIC
ZONE TO THE NORTH. THE SYSTEM IS EXPECTED TO INTENSIFY THROUGH TAU
36 DUE TO ENHANCED POLEWARD OUTFLOW INTO THE MID-LATITUDE
WESTERLIES. DURING EXTRA-TROPICAL TRANSITION (ET), TS 13W IS
EXPECTED TO REMAIN INTENSE, AS STRONG UPPER LEVEL DIFFLUENCE AND A
SHARP TEMPERATURE GRADIENT ASSOCIATED WITH THE APPROACHING UPPER
LEVEL TROUGH PROVIDE A STRONG BAROCLINIC DEVELOPMENT MECHANISM. TS
13W IS EXPECTED TO COMPLETE ET BY TAU 72 AS AN INTENSE EXTRA-
TROPICAL LOW. NUMERICAL MODEL GUIDANCE REMAINS IN STRONG AGREEMENT;
THEREFORE THIS FORECAST IS CLOSE TO MODEL CONSENSUS.//

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
To unsubscribe from WX-TROPL send e-mail to [email-masked] with
"unsub wx-tropl" in the body of your message. For help with WX-TROPL
write to [email-masked]. For more information on tropical weather products, see the NHC Homepage at http://www.nhc.noaa.gov.