MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 34W (MAN-YI) WARNING NR 31// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 34W (MAN-YI), LOCATED APPROXIMATELY 331 NM EAST-SOUTHEAST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED NORTH- NORTHEASTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A BROAD, EXPOSED LOW- LEVEL CIRCULATION CENTER WITH DEEP CONVECTION SHEARED EAST DUE TO STRONG WESTERLY VERTICAL WIND SHEAR (VWS). ADDITIONALLY, MSI SHOWS A WEAK FRONTAL STRUCTURE WITH WARM FRONTAL PROCESSES FUELING PERSISTENT DEEP CONVECTION OVER THE EAST AND NORTHEAST QUADRANTS. THIS INCIPIENT FRONTAL STRUCTURE IS EVIDENT IN A 27/00Z AMSU TEMPERATURE ANOMALY CROSS-SECTION SHOWING A BROAD LOW-LEVEL WARM ANOMALY. THE INITIAL INTENSITY REMAINS ASSESSED AT 30 KNOTS BASED ON A 270109Z ASCAT IMAGE, WHICH SHOWS A SWATH OF 30 KNOT WINDS OVER THE EASTERN SEMICIRCLE ASSOCIATED WITH THE PERSISTENT DEEP CONVECTION. DVORAK INTENSITY ESTIMATES RANGE FROM T1.5 TO 2.0 (25 TO 30 KNOTS) AND ALSO SUPPORT THE INITIAL INTENSITY ASSESSMENT. TD 34W IS ACCELERATING ALONG THE NORTHERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) WITHIN THE MIDLATITUDE WESTERLIES AND IS CLEARLY BEGINNING EXTRA-TROPICAL TRANSITION (ETT). 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 34W IS FORECAST TO CONTINUE ACCELERATING NORTHEASTWARD WITHIN THE MIDLATITUDE WESTERLIES AND IS FORECAST TO COMPLETE ETT BY TAU 18 AS IT GAINS FRONTAL CHARACTERISTICS. SLIGHT INTENSIFICATION TO 35 KNOTS IS EXPECTED BY TAU 24. WITH THE EXCEPTION OF NAVGEM, THE BULK OF NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT WITH A 54NM SPREAD IN SOLUTIONS AT TAU 24, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC OFFICIAL FORECAST TRACK.// NNNN NNNN