Tropical Storm SANBA Advisory Mon Feb 12

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (SANBA)
WARNING NR 15//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 02W (SANBA), LOCATED APPROXIMATELY 806 NM EAST OF
PUERTO PRINCESA, PALAWAN, PHILIPPINES, HAS TRACKED WESTWARD AT 15
KNOTS OVER THE PAST SIX HOURS. ANIMATED MSI SHOWS THE SYSTEM HAS
UNDERGONE ANOTHER CYCLIC CONVECTIVE FLARE WITH NO DISCERNIBLE
IMPROVEMENT IN ORGANIZATION OR DEGREE OF WRAP INTO A DEFINED LLC. THE
INITIAL POSITION IS BASED ON THE LLC FEATURE IN THE MSI WITH FAIR
CONFIDENCE. THE INITIAL INTENSITY OF 35 KNOTS IS BASED ON THE HIGHER
END OF AGENCY DVORAK ESTIMATES RANGING FROM T2.0 TO T2.5. UPPER LEVEL
ANALYSIS INDICATES THE SYSTEM IS IN AN AREA OF MODERATE (15-20 KNOT)
VWS; HOWEVER, A STRONG POLEWARD OUTFLOW IN ADDITION TO WARM (29C)
SSTS, IS PROVIDING AMPLE VENTILATION TO THE ASSOCIATED CONVECTION. TS
02W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE STR TO THE
NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 02W WILL TRACK GENERALLY WEST-NORTHWESTWARD UNDER THE STR
TOWARD THE SOUTHERN PHILIPPINES THROUGH TAU 12. THE AFOREMENTIONED
MARGINALLY FAVORABLE ENVIRONMENTAL CONDITIONS WILL ALLOW FOR SLIGHT
INTENSIFICATION TO 40 KNOTS. AFTERWARD, THE STR WILL SLIGHTLY BUILD
AND DRIVE THE SYSTEM MORE WESTWARD AFTER MAKING LANDFALL OVER
NORTHERN MINDANAO JUST PRIOR TO TAU 24. LAND INTERACTION WILL
SLIGHTLY WEAKEN THE SYSTEM AND BY TAU 36, IT WILL BE REDUCED TO A
35-KNOT TS AS IT TRACKS ACROSS THE SULU SEA, PALAWAN, AND INTO THE
SOUTH CHINA SEA (SCS).
   C. IN THE EXTENDED TAUS, TS SANBA WILL TRACK MORE NORTHWESTWARD IN
THE SCS TOWARD SOUTHERN VIETNAM IN RESPONSE TO A RECEDING STR.
MARGINAL CONDITIONS IN THE SCS ASSOCIATED WITH A COLD SURGE WILL
CAUSE THE SYSTEM TO GRADUALLY WEAKEN TO 25 KNOTS BY TAU 120. DYNAMIC
MODEL GUIDANCE IS IN STRONG AGREEMENT UP TO TAU 48, LENDING HIGH
CONFIDENCE IN THE INITIAL TO MID PORTION OF THE JTWC FORECAST TRACK.
AFTERWARD, THERE IS A SIGNIFICANT SPREAD AMONG THE CONSENSUS MEMBERS,
LENDING LOW CONFIDENCE TO THE EXTENDED PORTION OF THE JTWC TRACK
FORECAST.//
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