Tropical Storm THIRTYFIVE Advisory 12月26日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 35W (THIRTYFIVE)
WARNING NR 06//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 35W (THIRTYFIVE), LOCATED APPROXIMATELY
165 NM NORTH OF KOROR, PALAU, HAS TRACKED NORTHWESTWARD AT 13 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS A RAGGED AND SOMEWHAT DISORGANIZED SYSTEM, WITH AN OBSCURED
AND WEAK LLCC. MOST OF THE DEEPEST CONVECTION LIES WELL TO THE NORTH
OF THE ASSESSED CENTER, ALONG THE SHEAR AXIS, WITH A SMALL POCKET OF
CONVECTION DEVELOPING NEAR THE LLCC OVER THE PAST HOUR OR TWO. THE
INITIAL POSITION IS PLACED WITH MODERATE CONFIDENCE BASED ON AN
EXTRAPOLATION OF A 251622Z AMSR2 36 GHZ MICROWAVE IMAGE, SHOWING SOME
FORMATIVE RAIN BANDS BEGINNING TO WRAP IN FROM THE SOUTH, GIVING AN
INDICATION OF THE LLCC. THE INITIAL INTENSITY OF 25 KNOTS IS ASSESSED
WITH HIGH CONFIDENCE BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF
T1.5/25KTS FROM PGTW AND RJTD, AS WELL AS A 251240Z ASCAT-B PASS,
WHICH SHOWED A MAXIMUM OF 25 KNOTS TO THE NORTH OF THE CENTER.
AUTOMATED DVORAK ESTIMATES ARE SOMEWHAT HIGHER AT T2.5 (35 KNOTS) AND
SATCON IS 40 KNOTS, BUT BOTH ARE UNREALISTICALLY HIGH AS THEY ARE
FIXING THE CENTER TO THE NORTH IN THE DEEP CONVECTION, AND SO ARE
DISCOUNTED AT THIS TIME. SURFACE OBSERVATIONS FROM KOROR OVER THE
PAST SIX HOURS INDICATE SUSTAINED 10-15 KNOTS, WHILE TWO SHIP
OBSERVATIONS ROUGHLY THREE DEGREES TO THE NORTHWEST INDICATE 20-24
KNOT SUSTAINED WINDS. ENVIRONMENTAL ANALYSIS SHOWS A
MARGINALLY-FAVORABLE ENVIRONMENT WITH MODERATE (15 TO 20 KNOT)
SOUTHEASTERLY VERTICAL WIND SHEAR (VWS) BEING PARTIALLY OFFSET BY
GOOD POLEWARD OUTFLOW. SSTS IN THE PHILIPPINE SEA ARE FAVORABLE AT
29-30 CELSIUS. TD 35W IS TRACKING ALONG THE SOUTHWEST PERIPHERY OF
THE SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 35W WILL TRACK TOWARDS THE NORTHWEST THROUGH TAU 36 UNDER
THE INFLUENCE OF THE STR, WHICH REMAINS ENTRENCHED IN THE NORTHERN
PHILIPPINE SEA. BEYOND TAU 48, THE TRACK FLATTENS TO MORE WESTWARD,
AS THE RIDGE REORIENTS AND BUILDS TOWARDS THE WEST. TD 35W IS
EXPECTED TO MAKE LANDFALL ALONG THE COAST OF SAMAR ISLAND AS A WEAK
TROPICAL STORM PRIOR TO TAU 60 AND THEN TRANSIT INTO THE SIBUYAN SEA
BY TAU 72. TD 35W IS FORECAST TO SLOWLY INTENSIFY OVER THE NEXT 48
HOURS, WITH GENERALLY GOOD POLEWARD OUTFLOW BEING OFFSET BY
RELATIVELY HIGH VWS AND KEEPING A CAP ON THE INTENSIFICATION RATE.
AFTER MAKING LANDFALL, THE ADDITION OF LAND INTERACTION WILL REDUCE
THE INTENSITY TO 35 KNOTS BY TAU 72. AVAILABLE MODEL GUIDANCE IS IN
STRONG AGREEMENT THROUGH TAU 72, WITH NAVGEM BEING THE ONLY
SIGNIFICANT OUTLIER, TRENDING TOWARDS THE NORTH OF ALL OTHER MODELS.
THERE IS OVERALL HIGH CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST
TRACK.
   C. AFTER TAU 72, TD 35W WILL REMAIN ON A WESTWARD TRACK,
REEMERGING OVER WATER IN THE SOUTH CHINA SEA (SCS) BY ABOUT TAU 84.
ONCE FULLY INTO THE SCS BY TAU 96, THE SYSTEM WILL SLOWLY REINTENSIFY
UNDER INCREASED POLEWARD OUTFLOW AND LOW TO MODERATE VWS, BEING
OFFSET BY EXPOSURE TO RELATIVELY COOLER AND DRIER AIR ASSOCIATED WITH
A NORTHEAST WIND SURGE EVENT IN THE SCS. MODEL GUIDANCE IS IN LESS
AGREEMENT BEYOND TAU 72, WITH NAVGEM AS THE SOLE NORTHWARD OUTLIER,
THE GFS AND ECMWF DEFINING A MIDDLE TRACK, AND MOST OF THE MESOSCALE
GUIDANCE SHOWING A DIVE TOWARDS THE SOUTH. THE OFFICIAL TRACK LIES
NEAR THE ECMWF AND GFS TRACK, AND JUST SOUTH OF THE MULTIMODEL
CONSENSUS. THERE IS OVERALL HIGH CONFIDENCE IN THIS PORTION OF THE
JTWC FORECAST.//
NNNN
NNNN