Tropical Storm SANBA Advisory Tue Feb 13

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (SANBA) WARNING NR
19//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 02W (SANBA), LOCATED APPROXIMATELY 374 NM
SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 11 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS AN ELONGATED AREA OF CONVECTION, MAINLY TO THE NORTH OF THE
LOW LEVEL CIRCULATION CENTER (LLCC) ASSOCIATED WITH TS 02W. THE
INITIAL POSITION IS BASED ON A 130613Z 85 GHZ MICROWAVE IMAGE,
WHICH SHOWS WEAK BANDING WITH THE MAJORITY OF THE CONVECTION
LOCATED TO THE NORTH OF THE LLCC. THE INITIAL INTENSITY OF 35 KNOTS
IS HEDGED BETWEEN A 130155Z METOP-B ASCAT IMAGE WHICH SHOWS SOME 30
KNOT WIND BARBS AND A 121656Z SATCON ESTIMATE OF 47 KNOTS. UPPER
LEVEL ANALYSIS SHOWS MODERATE (15 TO 20 KNOT) VERTICAL WIND SHEAR
AND GOOD RADIAL OUTFLOW. SEA SURFACE TEMPERATURES AROUND THE
CENTRAL PHILIPPINES ARE FAVORABLE, RANGING BETWEEN 27 TO 28 DEGREES
CELSIUS. HOWEVER, TS 02W IS NOW INTERACTING WITH LAND WHICH IS
LIMITING DEVELOPMENT. TS 02W IS TRACKING WESTWARD ALONG THE
SOUTHWESTERN EDGE OF THE SUBTROPICAL RIDGE (STR) LOCATED TO THE
NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 02W WILL CONTINUE TRACKING WESTWARD BEFORE IT ROUNDS THE
SOUTHWESTERN EDGE OF THE STR. CONTINUED LAND INTERACTION THROUGH
TAU 12 WILL SLIGHTLY WEAKEN TS 02W TO 30 KNOTS. BEYOND TAU 24, TS
02W WILL TRACK OVER PALAWAN AND THEN INTO THE SOUTH CHINA SEA. THE
STR WILL BEGIN TO STEER TS 02W ON A MORE NORTHWESTWARD TRACK BY TAU
36. INTERACTION WITH WARM WATERS IN THE SOUTHEAST PORTION OF THE
SOUTH CHINA SEA WILL ALLOW FOR SLIGHT INTENSIFICATION TO 35 KNOTS
BY TAU 36. AFTER TAU 48, TS 02W WILL MOVE INTO COOLER, UNFAVORABLE
WATERS AND BEGIN TO DECREASE IN INTENSITY. TS 02W WILL CONTINUE TO
TRACK NORTHWESTWARD AS IT REMAINS UNDER THE INFLUENCE OF THE STR TO
THE NORTHEAST.
   C. IN THE EXTENDED FORECAST, BEYOND 72 HOURS, TS 02W WILL
CONTINUE TO WEAKEN DUE TO UNFAVORABLE SEA SURFACE TEMPERATURES,
NEAR 25 DEGREES CELSIUS. THE STR TO THE NORTHEAST WILL CONTINUE TO
STEER TS 02W TOWARDS VIETNAM. TS 02W WILL WEAKEN TO 25 JUST PRIOR
TO MAKING LANDFALL IN VIETNAM. AS TS 02W CONTINUES TO TRACK
WESTWARD OVER LAND IT WILL CONTINUE TO WEAKEN AND BY TAU 120 WILL
DISSIPATE WHILE OVER VIETNAM. NUMERICAL MODEL GUIDANCE IS IN GOOD
AGREEMENT WITH THE EXCEPTION OF COAMPS, WHICH TRACKS TS 02W TO THE
SOUTHWEST. OVERALL THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST
TRACK.//
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