Tropical Storm NOUL Advisory Thu Sep 17

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W (NOUL)
WARNING NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 13W (NOUL), LOCATED APPROXIMATELY 260 NM
WEST-SOUTHWEST OF MANILA, PHILIPPINES, HAS TRACKED WEST-
NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS FLARING CONVECTION
OBSCURING A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC).
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
LOCATION OF THE LLCC IN THE MSI LOOP AS WELL AS THE BANDING
FEATURES PRESENT IN 160506Z ATMS 183 GHZ AND 160553Z AMSR2 36GHZ
IMAGES. THE INITIAL INTENSITY OF 45 KTS IS PLACED WITH HIGH
CONFIDENCE AS WELL BASED ON THE 45 KTS WINDS WRAPPING INTO A
LOW LEVEL CIRCULATION PRESENT IN THE SCATTEROMETRY WIND FIELD
FROM A 160222Z ASCAT-B PASS AND IS IN AGREEMENT WITH A CIMSS
ADVANCED DVORAK TECHNIQUE CURRENT INTENSITY ESTIMATE OF T3.1 (47
KTS). TS NOUL CONTINUES TO TRACK ALONG THE SOUTHERN PERIPHERY OF
THE SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST AND THROUGH
AN ENVIRONMENT THAT IS MARGINALLY FAVORABLE FOR FURTHER DEVELOPMENT
WITH VERY WARM (30-32 CELSIUS) SEA SURFACE TEMPERATURES (SST) AND
ROBUST EQUATORWARD OUTFLOW ALOFT OFFSET BY MODERATE TO HIGH (15-25
KTS) VERTICAL WIND SHEAR (VWS) ALONG THE SOUTHWESTERN PERIPHERY OF
THE SYSTEM. UPPER LEVEL CONVERGENCE DUE TO THE DEEP EASTERLY FLOW
ALOFT ALSO CONTINUES TO STIFLE POLEWARD OUTFLOW AND LIMIT
INTENSIFICATION, DESPITE THE CONDUCIVE SSTS.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS NOUL WILL CONTINUE TO TRACK GENERALLY WEST-NORTHWESTWARD
UNDER THE STEERING INFLUENCE OF THE STR THROUGHOUT THE FORECAST
PERIOD. AS IT TRAVERSES OVER THE VERY WARM WATERS OF THE SOUTH CHINA
SEA, IT WILL CONTINUE TO INTENSIFY DESPITE CONTINUED MODERATE TO HIGH
(15-25 KTS) VWS TO A MAXIMUM INTENSITY OF 65 KTS BY TAU 36. BETWEEN
TAU 36 AND TAU 48 THE SYSTEM WILL MAKE LANDFALL NEAR HUE, VIETNAM AND
MAY INTENSIFY SLIGHTLY DURING THIS TIME PRIOR TO REACHING THE COAST.
AFTER MAKING LANDFALL JUST AFTER TAU 48, THE SYSTEM WILL BEGIN TO
WEAKEN DUE TO INTERACTION WITH THE UNDERLYING TERRAIN. AS TS NOUL
DRAGS DEEPER INTO THE INDOCHINA PENINSULA THROUGH LAOS AND INTO
THAILAND, IT WILL BEGIN TO DISSIPATE OVER LAND AND WEAKEN TO 35 KTS
BY TAU 72. NUMERICAL MODEL SOLUTIONS ARE IN FAIR AGREEMENT FOR THIS
INITIAL PORTION OF THE FORECAST PERIOD WITH A 115 NM SPREAD IN ACROSS
TRACK SOLUTIONS AT TAU 48 THAT INCREASES TO 218 NM BY TAU 72. THIS
FAIR AGREEMENT IN SOLUTIONS LENDS OVERALL FAIR CONFIDENCE TO THE
INITIAL PORTION OF THE JTWC FORECAST TRACK.
   C. AFTER TAU 72, TS NOUL WILL CONTINUE TO DETERIORATE AS IT DRAGS
ACROSS THE MOUNTAINOUS TERRAIN OF NORTHERN THAILAND, LEADING TO
DISSIPATION AFTER IT CROSSES INTO MYANMAR. NUMERICAL MODEL SOLUTIONS
ARE IN FAIR AGREEMENT WITH A MAXIMUM ACROSS TRACK SPREAD OF 358 NM
BY TAU 96 NM, AND LEND FAIR CONFIDENCE IN THE OVERALL JTWC FORECAST
TRACK WHICH IS PLACED ALONG THE MULTI-MODEL CONSENSUS.//
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