Tropical Storm THIRTYFIVE Advisory Tue Dec 25

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 35W (THIRTYFIVE)
WARNING NR 04//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 35W (THIRTYFIVE), LOCATED APPROXIMATELY
78 NM EAST OF KOROR, HAS TRACKED NORTHWESTWARD AT 05 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS
AN EXPOSED, WEAK, AND RAGGED LOW-LEVEL CIRCULATION (LLC) WITH
POORLY-ORGANIZED FLARING DEEP CONVECTION SHEARED TO THE NORTHWEST OF
THE LLC. FRAGMENTED FORMATIVE BANDS CAN BE SEEN SPIRALING IN FROM THE
SOUTHERN FLANKS. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE
BASED ON THE EXPOSED LLC IN THE MSI LOOP. THE INITIAL INTENSITY OF 25
KNOTS IS BASED ON DVORAK ESTIMATES OF T1.5/25KTS FROM PGTW AND KNES.
SURFACE OBSERVATIONS FROM KOROR OVER THE PAST SIX HOURS INDICATE
SUSTAINED 10-15 KNOTS WITH GUSTS UP TO 27 KNOTS. UPPER-LEVEL
ANALYSIS REVEALS A MARGINALLY-FAVORABLE ENVIRONMENT WITH MODERATE TO
STRONG (20 TO 25 KNOT) SOUTHEASTERLY VERTICAL WIND SHEAR (VWS)
OFFSET BY GOOD POLEWARD OUTFLOW. SSTS IN THE PHILIPPINE SEA ARE
PERENNIALLY FAVORABLE AT 28-30 CELSIUS. TD 35W IS TRACKING ALONG THE
SOUTHWEST PERIPHERY OF THE 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. AS THE STR BUILDS, TD 35W IS FORECAST TO TRACK ON A MORE
WEST-NORTHWESTWARD DIRECTION IN THE PHILIPPINE SEA TOWARD THE VISAYAN
ISLANDS, MAKING LANDFALL OVER LEYTE JUST BEFORE TAU 72. DESPITE THE
GOOD OUTFLOW AND WARM SSTS, MODERATE VWS IS EXPECTED TO PERSIST,
LIMITING INTENSIFICATION OF ONLY UP TO 40 KNOTS BY TAU 48. AFTERWARD,
THE ADDITION OF LAND INTERACTION WILL REDUCE THE INTENSITY BACK TO 30
KNOTS BY TAU 72.
   C. AFTER TAU 72, TD 35W WILL STAY ON THE SAME TRACK UNDER THE STR
BUT WILL STRUGGLE ACROSS THE VISAYAN ISLANDS AND BARELY MAINTAIN TD
INTENSITY. AFTER TAU 96, IT WILL EXIT INTO THE SOUTH CHINA SEA (SCS)
AND REGAIN ONLY MINIMAL TS STRENGTH, EVEN AFTER IT CLEARS LANDMASS
AND VWS DECREASES, DUE TO EXPOSURE TO A STRONG NORTHEAST WIND SURGE
EVENT IN THE SCS. WITH NAVGEM AS THE SOLE NORTHWARD OUTLIER,
NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT; THEREFORE, THERE IS
HIGH CONFIDENCE IN ALL PORTIONS OF THE JTWC FORECAST TRACK THAT IS
LAID JUST SOUTH OF THE MODEL CONSENSUS TO OFFSET NAVGEM.//
NNNN
NNNN