Tropical Storm MAN-YI Advisory 11月26日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 34W (MAN-YI) WARNING NR 25//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 34W (MAN-YI), LOCATED APPROXIMATELY 567 NM
SOUTHEAST OF KADENA AB, HAS TRACKED WEST-NORTHWESTWARD AT 11 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A RAPIDLY WEAKENING AND DISORGANIZING SYSTEM, WITH A
FULLY EXPOSED LLCC BECOMING EVIDENT OVER THE PAST SIX HOURS. A
251731Z GPM 36 GHZ MICROWAVE IMAGE CONFIRMS THE LLCC IS EXPOSED TO
THE NORTHWEST OF AN AREA OF WEAK CONVECTION, PRESSURED BY WESTERLY
VERTICAL WIND SHEAR AND WEAK CONVECTIVE BANDS WRAPPING INTO THE
LLCC. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
THE EXPOSED LLCC AND SUPPORTING MICROWAVE IMAGE. THE INITIAL
INTENSITY IS ASSESSED WITH LOW CONFIDENCE AT 60 KNOTS, ON ANALYSIS
OF DVORAK CURRENT INTENSITY ESTIMATE FROM PGTW OF T3.0 (45 KTS), A
CURRENT INTENSITY ESTIMATE OF T4.5 (77 KTS) FROM KNES ESTIMATE, AND
AN AUTOMATED INTENSITY ESTIMATE OF T3.8 (60 KTS). THE UPPER LEVEL
ENVIRONMENT HAS BECOME MUCH MORE COMPLEX OVER THE PREVIOUS SIX
HOURS, WITH AN UPPER ANTICYCLONE SHIFTING TO THE SOUTHWEST OF THE
LLC, PROVIDING INCREASED WESTERLY VWS, NOW ESTIMATED BETWEEN 15-20
KNOTS, BUT 180 DEG OUT OF PHASE WITH THE STORM MOTION, LEADING TO
THE RAPID DECAY OF THE CONVECTIVE CORE. THIS COMBINED WITH A
REDUCTION IN UPPER LEVEL OUTFLOW, HAS OFFSET THE HIGH SEA SURFACE
TEMPERATURES (SSTS), ALLOWING FOR THE RAPID WEAKENING EVIDENT IN THE
PAST SIX HOURS. TS 34W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY
OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE
NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 34W IS FORECAST TO CONTINUE TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF THE STEERING RIDGE, WITH THE TRACK BECOMING
INCREASINGLY NORTH, THEN NORTHEASTWARD AS IT ROUNDS THE RIDGE AXIS
BY TAU 36, AND THEREAFTER ACCELERATES TO THE NORTHEAST. TS 34W WILL
CONTINUE TO RAPIDLY WEAKEN OVER THE NEXT 12 HOURS DUE TO THE HIGH
VWS AND RELATIVELY LOW OUTFLOW. THE RATE OF WEAKENING WILL DECREASE
SOMEWHAT AFTER THAT, AS THE HIGH VWS IS OFFSET BY INCREASING OUTFLOW
AS THE SYSTEM TAPS INTO THE MID-LATITUDE WESTERLY FLOW TO THE NORTH.
TS 34W IS FORECAST TO BEGIN EXTRATROPICAL TRANSITION BY TAU 36,
COMPLETING THE TRANSITION BY TAU 72 AS A 30 KNOT SYSTEM, AS IT
BECOMES EMBEDDED IN THE BAROCLINIC ZONE AND UNDER THE WESTERLIES.
AVAILABLE NUMERICAL GUIDANCE IS IN STRONG DISAGREEMENT AFTER TAU 36,
AFTER THE SYSTEM ROUNDS THE RIDGE AXIS. THERE REMAINS AN ALTERNATE
DISSIPATION SCENARIO, UNDER WHICH THE SYSTEM DISSIPATES BELOW
WARNING CRITERIA PRIOR TO COMPLETION OF ETT. THE GALWEM MODEL IS THE
WESTERN OUTLIER WITH A MORE GRADUAL POLEWARD TURN, WHILE THE NAVGEM
AND JGSM ARE THE WESTERN OUTLIERS AND SHOW A MORE RAPID TURN, THEN
DISSIPATION AND A TURN TO THE SOUTHEAST BY TAU 72. THE OFFICIAL
FORECAST TRACK LIES CLOSE TO THE GFS SOLUTION, INSIDE AND SLOWER
THAN THE CONSENSUS THROUGH TAU 48, THEN INSIDE AND FASTER THROUGH
TAU 72. DUE TO THE HIGH UNCERTAINTY IN THE AVAILABLE GUIDANCE, THERE
IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST TRACK.//
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