Tropical Storm THIRTYFIVE Advisory Mon Dec 24

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 35W (THIRTYFIVE)
WARNING NR 02//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 35W (THIRTYFIVE), LOCATED APPROXIMATELY
84 NM EAST OF KOROR, HAS TRACKED WEST-NORTHWESTWARD AT 06 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS AN EXPOSED, QUASI-STATIONARY SYSTEM WITH POORLY-ORGANIZED
DEEP CONVECION FLARING OVER THE NORTHERN SEMICIRCLE. A 241759Z SSMI
85GHZ COMPOSITE IMAGE AND A 241746Z F-15 NIGHTTIME VISIBLE IMAGE
SHOW SHALLOW BANDING WRAPPING INTO A COMPACT, DEFINED LOW-LEVEL
CIRCULATION CENTER, CONSEQUENTLY, THERE IS GOOD CONFIDENCE IN THE
CURRENT POSITION. THE CURRENT INTENSITY REMAINS ASSESSED AT 25 KNOTS
BASED ON RECENT ASCAT DATA, DVORAK INTENSITY ESTIMATES OF T1.5 (25
KNOTS) FROM PGTW AND KNES AND SLP OBSERVATIONS OF 1003MB FROM KOROR.
UPPER-LEVEL ANALYSIS REVEALS A MARGINALLY-FAVORABLE ENVIRONMENT WITH
MODERATE TO STRONG (20 TO 25 KNOTS) SOUTHEASTERLY VERTICAL WIND
SHEAR (VWS) OFFSET SOMEWHAT BY BROAD POLEWARD DIFFLUENCE ALOFT. TD
35W IS TRACKING ERRATICALLY WITHIN A COMPETING STEERING ENVIRONMENT
BETWEEN A NEAR-EQUATORIAL RIDGE TO THE SOUTH AND A SUBTROPICAL RIDGE
(STR) ENTRENCHED TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 35W IS FORECAST TO TRACK SLOWLY NORTHWESTWARD TO WEST-
NORTHWESTWARD THROUGH TAU 48 TOWARD A TEMPORARY WEAKNESS IN THE
AFOREMENTIONED STR. SEA SURFACE TEMPERATURES WILL REMAIN FAVORABLE
DURING THIS TIME, HOWEVER, MODERATE VWS (20 TO 25 KNOTS) IS EXPECTED
TO PERSIST, WHICH WILL SLOW DEVELOPMENT. AFTER TAU 48, THE STR WILL
BEGIN TO BUILD ALLOWING TD 35W TO TRACK WESTWARD. ADDITIONALLY,
VWS WILL DECREASE SLIGHTLY, WHICH WILL ALLOW THE SYSTEM TO INCREASE
IN INTENSITY TO 45 KNOTS BY TAU 72. NUMERICAL MODEL GUIDANCE IS IN
GOOD AGREEMENT WITH A SPREAD OF 120NM AT TAU 72, THEREFORE, THERE IS
HIGH CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.
   C. AFTER TAU 72, VWS WILL DECREASE FURTHER, HOWEVER, INTERACTION
WITH LAND AS THE SYSTEM CROSSES THE CENTRAL PHILIPPINES WILL HINDER
DEVELOPMENT. AS TD 35W EMERGES OVER THE SOUTH CHINA SEA, IT IS
FORECAST TO TRACK WESTWARD UNDER THE STEERING INFLUENCE OF THE LOW-
TO MID-LEVEL STR. TD 35W WILL ALSO BEGIN TO INTERACT WITH A
NORTHEAST SURGE EVENT BY TAU 120, WHICH WILL ALSO PREVENT ADDITIONAL
DEVELOPMENT. NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT,
THEREFORE, THERE IS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC
FORECAST TRACK.//
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