Subject: Pacific-NW: Subj/prognostic Reasoning For Typhoon 12w Warning Nr 22//

From: SIU Weather Processor <[email-masked]>
Date: Sun, 19 Sep 2010 21:44:13 -0500

WDPN31 PGTW 200300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W WARNING NR 22//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TYPHOON (TY) 12W (FANAPI), LOCATED APPROXIMATELY 210 NM EAST-
NORTHEAST OF HONG KONG, CHINA, HAS TRACKED WEST-NORTHWESTARD AT 13
KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON A
192332Z PGTW SATELLITE FIX AND A 192331Z SSMIS IMAGE SHOWING A CLEAR
CENTER FEATURE. THE INTENSITY OF 65 KNOTS IS CONSISTENT WITH CURRENT
DVORAK INTENSITY ESTIMATES FROM PGTW AND RJTD. TY 12W CONTINUES TO
TRACK ALONG THE SOUTHERN PERIPHERY OF AN EXTENSIVE STEERING RIDGE TO
THE NORTH AND IS PRESENTLY MAKING LANDFALL BETWEEN SHANTOU AND
XIAMEN, CHINA. INTERACTION WITH LAND HAS EXPOSED THE WESTERN PORTION
OF THE LOW LEVEL CIRCULATION CENTER (LLCC), WHILE DEEP CONVECTION
PERSISTS OVER WATER IN THE STRONG CONVERGENT FLOW ALONG THE EASTERN
PORTION OF THE LLCC.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE IN THE OVERALL FORECAST PHILOSOPHY FROM THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 12W IS FORECAST TO CONTINUE TRACKING ALONG THE SOUTHERN
PERIPHERY OF A SUBTROPICAL STEERING RIDGE ANCHORED OVER NORTHEASTERN
CHINA THROUGHOUT THE FORECAST PERIOD. AS THE SYSTEM CONTINUES
TRACKING OVER LAND IT WILL STEADILY DISSIPATE BELOW THE WARNING
THRESHOLD INTENSITY OF 25 KNOTS BY TAU 24.//

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