TROPICAL CYCLONE ADVISORY
NOV 29 2009
WESTERN PACIFIC WIND
SUPER TYPHOON NIDA WIND
SUPER TYPHOON NIDA THERMAL IR IMAGERY
SUPER TYPHOON NIDA RAIN ANALYSIS
WESTERN PACIFIC PRESSURE AND STEERING ENVIRONMENT
WESTERN PACIFIC IR IMAGERY
SUPER TYPHOON NIDA (26W)
SUPER TYPHOON (CATEGORY 4) STAGE
CURRENT INTENSITY: MAX: 125kt GUST: 150kt (232-278kph)
CURRENT PRESSURE: 929MB
SURFACE WIND ANALYSIS: 127KT (235KPH) MSLP: 915.8MB
ADVANCE DVORAK TECHNIQUES (ADT): 127.0KT(235KPH) MSLP: 915.5MB
CENTRAL REGION TEMP: -17.9C (LARGE EYE)
CENTRAL CLOUD TEMP: -65.4C (+35MM/HR)
FORECAST 12HRS: 120KT/222KPH
DISCUSSION:
TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 345 NM SOUTH-SOUTHWEST OF IWO TO, HAS TRACKED NORTHEASTWARD AT 01 KNOT OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 282141Z SSMI/S IMAGE DEPICT SLIGHT EROSION OF CORE CONVECTION OVER THE EAST QUADRANT WITH AN EXPANDING, ROUND 50NM DIAMETER EYE. ANIMATED WATER VAPOR IMAGERY STILL INDICATES EXCELLENT RADIAL OUTFLOW WITH ENHANCED POLEWARD OUTFLOW INTO THE MIDLATITUDE WESTERLIES. THE CURRENT INTENSITY IS BASED ON THE HIGHER END OF DVORAK ESTIMATES RANGING FROM 115 TO 127 KNOTS FROM PGTW, KNES AND RJTD. THE MOST RECENT 500MB ANALYSIS DEPICTS A POLEWARD-ORIENTED, MID-LEVEL SUBTROPICAL RIDGE (STR) POSITIONED EAST OF THE SYSTEM WITH MIDLATITUDE WESTERLIES NORTH OF 22N; TY 26W IS LOCATED WITHIN A RELATIVELY WEAK STEERING ENVIRONMENT BETWEEN THE EASTERN, DOMINANT STR AND THE WESTERN STR, WHICH EXTENDS FROM HAINAN EASTWARD TO ABOUT 130E. THE UPPER-LEVEL FLOW REMAINS HIGH ZONAL ACROSS ASIA WITH NO SIGNIFICANT MID-LEVEL SHORT-WAVE TROUGHS EVIDENT IN THE UPSTREAM FLOW (IN IMAGERY AS WELL). THE 28/21Z SURFACE ANALYSIS DEPICTS BROAD HIGH PRESSURE ACROSS ASIA EXTENDING EASTWARD TO 150E; THIS HIGH HAS BUILT EASTWARD OVER THE PAST 24 HOURS AND IS ENTRENCHED NORTH OF TY 26W. THE LATEST TOTAL PRECIPITABLE WATER PRODUCTS INDICATE A STRONG SOUTHWARD PUSH OF COOLER, DRIER AIR WITH THE RIDGING NORTH OF THE SYSTEM AND WEST OF THE SYSTEM
FORECAST REASONING.
A. THIS BULLETIN REFLECTS A SIGNIFICANT FORECAST PHILOSOPHY CHANGE FROM A RE-CURVE SCENARIO TO A DISSIPATION SCENARIO IN ACCORDANCE WITH OUR PREVIOUSLY DISCUSSED ALTERNATE SCENARIO.
B. NUMERICAL GUIDANCE REMAINS IN POOR AGREEMENT ON THE TRACK, HOWEVER, THE MAJORITY OF AIDS (UKMO, ECMWF, TC-LAPS, JGSM, NOGAPS, GFS AND WBAR) NOW SUPPORT THE DISSIPATION SCENARIO WITH GFDN STILL INDICATING A RE-CURVE TRACK. THE UKMO, ECMWF, JGSM, TC-LAPS AND GFS INDICATE A WESTWARD TO NORTHWESTWARD TRACK AND DISSIPATION WHILE NOGAPS AND WBAR SHOW A FASTER NORTHEASTWARD TRACK AND DISSIPATION AROUND 27N 148E. THIS FORECAST FAVORS A SLOW NORTHWARD TO NORTH-NORTHEASTWARD TRACK ALONG THE WESTERN PERIPHERY OF THE EASTERN STR AND SIGNIFICANT WEAKENING THROUGH TAU 72. THE DISSIPATION SCENARIO IS BASED ON INCREASING VERTICAL WIND SHEAR DUE TO A COMBINATION OF LOW-LEVEL NORTHEASTERLY FLOW, ASSOCIATED WITH THE RIDGE BUILDING NORTH OF THE SYSTEM, AND ZONAL UPPER-LEVEL WESTERLY FLOW.
C. IN THE EXTENDED TAUS, TY 26W WILL CONTINUE TRACKING NORTHWARD AND WILL WEAKEN TO 25 KNOTS OR LESS. SUBSEQUENTLY, THE SYSTEM IS EXPECTED TO TURN SOUTHWESTWARD AND ACCELERATE WITHIN THE LOW-LEVEL NORTHEASTERLY FLOW. THERE IS STILL UNCERTAINTY WITH THE TIMING OF THE DISSIPATION AND THE TURN SOUTHWESTWARD BUT OVERALL CONFIDENCE HAS INCREASED OVER THE PAST 24 HOURS WITH THE MAJORITY OF MODELS SUPPORTING THE SYNOPTIC PATTERN.
TROPICAL DISTURBANCE 97W INVEST
SEVERE ALERT (24HRS FORMATION) STAGE
CURRENT INTENSITY: MAX: 15kt GUST: 20kt (28-37kph)
CURRENT PRESSURE: 1010MB
SURFACE WIND ANALYSIS: 23KT (43KPH) MSLP: 1006.9MB
ADVANCE DVORAK TECHNIQUES (ADT): 0KT(0KPH) MSLP: 0MB
CENTRAL REGION TEMP: -0C (N/A)
CENTRAL CLOUD TEMP: -0C (+35MM/HR)
FORECAST 12HRS: 0KT/0KPH
JUST VOTE OR COMMENT FOR FEEDBACK
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