Tropical Storm NOCK-TEN Advisory Pzt, 26.12.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W (NOCK-TEN) WARNING NR 19//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 30W (NOCK-TEN), LOCATED APPROXIMATELY 134 NM EAST-
SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 10 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
(EIR) IMAGERY SHOWS THE SYSTEM HAS MADE LANDFALL AND IS NOW DRAGGING
ACROSS SOUTHERN LUZON. CONVECTIVE BANDS HAVE BECOME MORE SHALLOW AND
SLIGHTLY UNRAVELED DUE TO THE LAND INTERACTION. ADDITIONALLY, THE EYE
FEATURE HAS BECOME CLOUD-FILLED. THE INITIAL POSITION IS BASED ON A
WARM PIXEL CLUSTER ON THE CENTRAL CONVECTION AND ON A CIRCULATION
FEATURE ON A COMPOSITE RADAR REFLECTIVITY LOOP FROM TAGAYTAY CITY.
THE INITIAL INTENSITY OF 100 KNOTS IS EXTRAPOLATED FROM DVORAK
ESTIMATES PRIOR TO LANDFALL AND FROM NEARBY OBSERVING STATIONS.
UPPER-LEVEL ANALYSIS INDICATES THAT SANS THE LAND INTERACTION, TY 30W
CONTINUES TO TRACK IN AN AREA OF LOW (05-10 KNOT) VERTICAL WIND SHEAR
(VWS) AND EXCELLENT RADIAL OUTFLOW. THE CYCLONE IS 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. TY NOCK-TEN WILL TURN WEST-NORTHWESTWARD TOWARD A DEVELOPING
WEAKNESS IN THE STEERING RIDGE, PASSING JUST SOUTH OF MANILA, BEFORE
EXITING INTO THE SOUTH CHINA SEA (SCS) BY TAU 18. AFTER TAU 24, TY
30W WILL GRADUALLY TURN SOUTHWESTWARD AS A SECONDARY STR CENTERED
OVER EASTERN CHINA ASSUMES STEERING. THE SYSTEM WILL STEADILY WEAKEN
DUE TO LAND INTERACTION. AFTER TAU 24, CONCURRENT WITH THE CHANGE TO
A SOUTHWESTWARD TRACK, TY 30W WILL RAPIDLY WEAKEN DUE TO INCREASED
VWS (20-25 KNOTS) AND EXPOSURE TO THE STRONG COLD NORTHEASTERLY SURGE
IN THE SCS. BY TAU 48, THE LOW LEVEL CIRCULATION IS EXPECTED TO
BECOME DECOUPLED FROM THE CONVECTION, FULLY DISSIPATING BY TAU 72.
DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH SOME SPREADING
IN THE SCS. THE JTWC FORECAST TRACK IS POSITIONED CLOSE TO THE
MULTI-MODEL CONSENSUS AND REMAINS CONSISTENT WITH PREVIOUS FORECASTS,
LEADING TO HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
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