Tropical Storm NOCK-TEN Advisory Dom, 25-12

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 30W (NOCK-TEN) WARNING
NR 17//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 30W (NOCK-TEN), LOCATED APPROXIMATELY 242 NM
EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 10
KNOTS OVER THE PAST SIX HOURS. ANIMATED HIGH-RESOLUTION VISIBLE
SATELLITE IMAGERY SHOWS A VERY SYMMETRIC SYSTEM WITH DEEP CONVECTIVE
BANDING WRAPPING INTO A WELL DEFINED 14 NAUTICAL MILE WIDE EYE. THE
INITIAL POSITION IS BASED ON THE EYE FEATURE IN THE VISIBLE IMAGERY,
AND ON ANALYSIS OF A COMPOSITE RADAR IMAGE FROM THE VIRAC DOPPLER
SITE ON CATANDUANES ISLAND, PHILIPPINES. ADDITIONALLY, A 0354Z AMSR-
2 COMPOSITE 89GHZ MICROWAVE PASS SHOWED A VERY SYMMETRICAL SYSTEM,
WITH A WELL DEFINED MICROWAVE EYE FEATURE WITH A VERY INTENSE
EYEWALL STRUCTURE. THE INITIAL INTENSITY OF 135 KNOTS IS BASED ON AN
OVERALL ASSESSMENT OF OBJECTIVE AND SUBJECTIVE DVORAK ESTIMATES FROM
ALL REPORTING AGENCIES. THE SYSTEM APPEARS TO HAVE PEAKED IN
INTENSITY AT 0300Z, WHEN ALL REPORTING AGENCIES REACHED T7.0 (140
KNOTS), BUT OVER THE PREVIOUS THREE HOURS, THE CONVECTIVE CLOUD TOPS
HAVE WARMED SOMEWHAT, LEADING TO LOWER INTENSITY ESTIMATES. THE
FIRST HINTS OF LAND INTERACTION ARE ALSO BEGINNING TO MANIFEST
THEMSELVES, AS THE SOUTHWESTERN PORTION OF THE SYSTEM IS BECOMING
LESS INTENSE. UPPER-LEVEL ANALYSIS SHOWS THAT STY 30W IS IN AN AREA
OF LOW (5-10 KNOT) VERTICAL WIND SHEAR (VWS), HAS EXCELLENT DUAL-
CHANNEL OUTFLOW, AND IS SITUATED OVER WARM (29 CELSIUS) SEA SURFACE
TEMPERATURES. STY NOCK-TEN CONTINUES TRACKING ALONG THE SOUTHERN
PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.	
B. STY 30W WILL TURN SLIGHTLY WEST-NORTHWESTWARD OVER THE NEXT 24-
HOURS TOWARD A DEVELOPING WEAKNESS IN THE STEERING RIDGE TO THE
NORTH. THE SYSTEM IS FORECAST TO MAKE LANDFALL OVER THE SOUTHERN
PORTION OF CATANDUANES ISLAND BY 25/1200Z THEN MOVE ACROSS SOUTHERN
LUZON, PASSING JUST SOUTH OF MANILA, BEFORE EXITING INTO THE SOUTH
CHINA SEA (SCS) BY ABOUT TAU 30. STY NOCK-TEN WILL GRADUALLY WEAKEN
AFTER LANDFALL DUE TO INTERACTION WITH THE RUGGED TERRAIN, BUT IS
EXPECTED TO REMAIN AT TYPHOON STRENGTH UNTIL IT REACHES THE SOUTH
CHINA SEA. AFTER TAU 36, THE SYSTEM IS FORECAST TO BEGIN A RAPID
WEAKENING TREND, AS VWS INCREASES AND THE SYSTEM INTERACTS WITH A
STRONG NORTHEASTERLY COLD SURGE IN THE SOUTH CHINA SEA. AFTER TAU
48, THE LOW LEVEL CIRCULATION IS EXPECTED TO BECOME DECOUPLED FROM
THE CONVECTION, AND THE CENTER WILL CURVE SOUTHWESTWARD.
C. AFTER TAU 72, SUPER TYPHOON NOCK-TEN WILL CONTINUE TO RAPIDLY
WEAKEN THEN FULLY DISSIPATE BY TAU 96. DYNAMIC MODEL GUIDANCE IS IN
GOOD AGREEMENT WITH SOME SPREAD IN THE LATER TAUS DUE TO UNCERTAINTY
IN THE DEGREE OF THE SOUTHWESTWARD TURN. THE JTWC FORECAST TRACK IS
POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS AND REMAINS FAIRLY
CONSISTENT WITH PREVIOUS FORECASTS AND THERE IS HIGH CONFIDENCE IN
THE JTWC FORECAST TRACK.//
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