WDPN31 PGTW 211500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 28W (TRAMI) 
WARNING NR 04//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 28W (TRAMI), LOCATED APPROXIMATELY 180 NM
NORTHWEST OF ANDERSEN AFB, GUAM, HAS TRACKED WEST-NORTHWESTWARD AT 10
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS DEEP CONVECTION LOCATED DIRECTLY ABOVE THE LOW LEVEL
CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON A 211105Z PARTIAL METOP-A ASCAT IMAGE WHICH SHOWS
THE LLCC. THE INITIAL INTENSITY OF 40 KNOTS IS ALSO BASED ON THE SAME
211105Z ASCAT IMAGE WHICH SHOWS A SWATH OF 40 KNOT WINDS TO THE NORTH
OF THE LLCC. ENVIRONMENTAL ANALYSIS SHOWS TS 28W CONTINUES TO
EXPERIENCE FAVORABLE VERTICAL WIND SHEAR (5 TO 10 KNOTS) AND
CONTINUES TO HAVE EXCELLENT RADIAL OUTFLOW. SEA SURFACE TEMPERATURES
ALSO REMAIN FAVORABLE FOR CONTINUED DEVELOPMENT, BETWEEN 29 AND 30
DEGREES CELSIUS. TS 28W IS TRACKING WEST-NORTHWESTWARD UNDER THE
INFLUENCE OF THE WEST TO EAST ORIENTATED SUBTROPICAL RIDGE (STR)
LOCATED TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. THROUGH TAU 72, THE AFOREMENTIONED STR WILL REMAIN THE PRIMARY
STEERING FEATURE. VERTICAL WIND SHEAR, UPPER LEVEL OUTFLOW, AND SEA
SURFACE TEMPERATURES ARE ALL CONDUCIVE FOR RAPID INTENSIFICATION. THE
POTENTIAL FOR RAPID INTENSIFICATION HAS BEEN CAPTURED BY MODEL
GUIDANCE AND IS EVEN MORE IMPRESSIVE THAN THE PREVIOUS MODEL RUN. AS
A RESULT, TS 28W WILL QUICKLY REACH AN INTENSITY OF 85 KNOTS BY TAU
48 AND 110 KNOTS BY TAU 72. DYNAMIC MODEL GUIDANCE IS IN GOOD
AGREEMENT WITH A MODEL SPREAD OF 120 NM BY TAU 72. THEREFORE, THERE
IS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.
   C. AFTER TAU 72, THE STR LOCATED TO THE NORTH WILL ERODE AS A
RESULT OF AN APPROACHING MID-LATITUDE TROUGH. THE STR TO THE WEST,
LOCATED OVER SOUTHERN CHINA, WILL ALSO BEGIN TO BUILD AT THIS TIME.
COMPETING STEERING FLOW DUE TO THE POSITIONING OF THE STRS WILL ALLOW
FOR TS 28W TO SLOW IN FORWARD SPEED. THE PLACEMENT OF THE STRS WILL
ALSO ALLOW TS 28W TO BECOME QUASI-STATIONARY AFTER TAU 96. VERTICAL
WIND SHEAR AND SEA SURFACE TEMPERATURES WILL REMAIN FAVORABLE DURING
THIS TIME PERIOD, ALLOWING TS 28W TO REACH AND INTENSITY OF 135 KNOTS
BY TAU 96 AND UP TO 140 KNOTS BETWEEN TAU 96 AND 120. DYNAMIC MODEL
GUIDANCE IS IN POOR AGREEMENT WITH A TRACK SPREAD OF 650 NM BY TAU
120. CTCI AND JGSI ARE THE PRIMARY OUTLIERS TO THE NORTHEAST AND
SOUTHWEST, RESPECTIVELY. THEREFORE, THERE IS LOW CONFIDENCE IN THIS
PORTION OF THE JTWC FORECAST TRACK WHICH IS PLACED NEAR THE
MULTI-MODEL CONSENSUS. THE JTWC INTENSITY FORECAST IS PLACED ABOVE
THE CONSENSUS BASED ON THE EXPECTED FAVORABLE VERTICAL WIND SHEAR AND
SEA SURFACE TEMPERATURES.//
NNNN