WDPN31 PGTW 230300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 30W (NOCK-TEN) WARNING
NR 08//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 30W (NOCK-TEN), LOCATED APPROXIMATELY 738 NM
EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD
AT 19 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS A TIGHTLY-WOUND LOW LEVEL CIRCULATION
CENTER (LLCC) WITH FORMATIVE BANDING WRAPPING INTO THE CENTER FROM
THE NORTH. A 222129Z CORIOLIS MICROWAVE IMAGE DEPICTS A VERY COMPACT
MICROWAVE EYE WITH CONVECTIVE BANDING ALONG THE NORTHERN AND
SOUTHERN PERIPHERIES. THE CURRENT POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE LLCC IN SATELLITE IMAGERY AND THE MICROWAVE
EYE FEATURE. THE INTENSITY HAS BEEN HELD AT 55 KNOTS BASED ON DVORAK
INTENSITY ESTIMATES OF T3.5 (55 KNOTS) FROM ALL REPORTING AGENCIES.
TS NOCK-TEN REMAINS IN A VERY FAVORABLE ENVIRONMENT WITH LOW (5-10
KNOTS) VERTICAL WIND SHEAR (VWS), NEARLY RADIAL OUTFLOW, AND VERY
WARM SEA SURFACE TEMPERATURES. TS 30W IS TRACKING WEST-NORTHWESTWARD
ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE
(STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 30W WILL CONTINUE TO TRACK WEST-NORTHWESTWARD OVER THE NEXT
24 HOURS BEFORE LEVELING OUT ON A MORE WESTWARD TRAJECTORY THROUGH
TAU 72, MAKING LANDFALL OVER SOUTHERN LUZON. TS NOCK-TEN WILL
CONTINUE TO INTENSIFY UNDER THE VERY FAVORABLE ENVIRONMENTAL
CONDITIONS WITH THE POTENTIAL FOR A PERIOD OF RAPID INTENSIFICATION
(WITHIN THE NEXT 24 TO 48 HOURS), DUE TO HIGH OCEAN HEAT CONTENT,
PRIOR TO REACHING THE EAST COAST OF THE PHILIPPINES. DYNAMIC MODEL
GUIDANCE HAS COME INTO TIGHTER AGREEMENT THROUGH THIS PORTION OF THE
FORECAST, WITH ONLY ECMWF TRACKING A MUCH WEAKER SYSTEM OVER CENTRAL
LUZON. THERE IS HIGH CONFIDENCE IN THIS PORTION OF THE FORECAST.
   C. IN THE EXTENDED FORECAST, TS 30W IS FORECAST TO TURN SLIGHTLY
WEST-NORTHWESTWARD AS IT APPROACHES THE WESTERN EDGE OF THE STR. THE
SYSTEM WILL WEAKEN DUE TO LAND INTERACTION AS IT TRACKS ACROSS THE
PHILIPPINES. AFTERWARDS TS NOCK-TEN WILL TURN TO THE SOUTHWEST WITH
THE NORTHEAST MONSOON FLOW AND ENCOUNTER COOLER, DRIER AIR AND
INCREASING VWS ASSOCIATED WITH THE COLD SURGE. DYNAMIC MODEL
GUIDANCE HAS IMPROVED IN THE LONG RANGE WITH A MAJORITY OF THE
MODELS SUPPORTING THE CURRENT FORECAST. ECMWF REMAINS FURTHER SOUTH
BUT SHOWS THE TURN TO THE SOUTHWEST. GFDN IS THE ONLY OUTLIER IN THE
EXTENDED FORECAST, AS IT ERRONEOUSLY TRACKS THE VORTEX SIGNATURE TO
THE NORTH AGAINST THE COLD SURGE. THE MULTI-MODEL CONSENSUS HAS
SHIFTED BACK TO THE SOUTH AND NOW LIES VERY CLOSE TO THE JTWC
FORECAST TRACK, WHICH IS LAID WITH HIGH CONFIDENCE.//