Tropical Storm NURI Advisory сб, 01.11.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (NURI) WARNING NR
04//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 20W (NURI), LOCATED APPROXIMATELY 784 NM EAST
OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 11 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
(EIR) SHOWS THE SYSTEM HAS FURTHER CONSOLIDATED. THIS IS EVIDENCED BY
COOLING CONVECTIVE TOPS OF THE CENTRAL DENSE OVERCAST FEATURE.
ADDITIONALLY, FEEDER BANDS HAVE WRAPPED TIGHTER INTO THE LOW LEVEL
CIRCULATION CENTER THAT HAS BECOME BETTER DEFINED. THE INITIAL
POSITION, WHICH IS ADJACENT TO AGENCY FIXES, IS BASED ON THE EIR LOOP
WITH GOOD CONFIDENCE. THE INITIAL INTENSITY OF 45 KNOTS IS
BASED ON CONGRUENT DVORAK ESTIMATES FROM PGTW, RJTD, AND KNES. UPPER
LEVEL ANALYSIS INDICATES THE SYSTEM IS SOUTH OF THE RIDGE AXIS IN AN
AREA WITH LOW (05-10 KNOT) VERTICAL WIND SHEAR (VWS) AND EXCELLENT
DUAL OUTFLOW. TS 20W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF AN
EXTENSION OF THE SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 20W IS EXPECTED TO TRACK MORE WEST-NORTHWESTWARD OVER THE
NEXT 36 HOURS AS THE STEERING STR WEAKENS AND RECEDES WITH THE
APPROACH OF A MID-LATITUDE TROUGH FROM THE NORTHWEST. AFTERWARDS, IT
WILL TRACK NORTHWARD THEN NORTHEASTWARD AS IT CRESTS AND MOVES
POLEWARD OF THE STR AXIS. FAVORABLE UPPER LEVEL CONDITIONS, IN
ADDITION TO VERY WARM SEA SURFACE TEMPERATURES (SSTS) ACROSS THE
PHILIPPINE SEA (GREATER THAN 28 CELSIUS), WILL FUEL RAPID
INTENSIFICATION, PEAKING AT 110 KNOTS BY TAU 72. NUMERIC MODEL
GUIDANCE, ALONG WITH ENSEMBLE DATA, IS IN GOOD AGREEMENT WITH THIS
PORTION OF THE FORECAST, LENDING TO HIGH CONFIDENCE THROUGH TAU 72.
   C. AFTER TAU 72, TS NURI IS EXPECTED TO TEMPORARILY BACK TO A
NORTH-NORTHWESTWARD TRAJECTORY AS THE STEERING STR REBUILDS BEFORE
ACCELERATING NORTHEASTWARD AS IT GETS ABSORBED INTO THE MID-LATITUDE
WESTERLIES. BY THE END OF FORECAST, THE CYCLONE WILL BEGIN
EXTRA-TROPICAL TRANSITION. DUE TO INCREASING VWS AND COOLING SSTS, TS
20W WILL GRADUALLY WEAKEN. MODEL GUIDANCE IS WIDELY SPREAD ON THIS
PORTION OF THE FORECAST TRACK DUE TO VARYING SOLUTIONS WITH THE
REBUILDING STR. THEREFORE, THERE IS LOW CONFIDENCE IN THE EXTENDED
PORTION OF THE FORECAST.//
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