Subject: Pacific-NW: 1. Typhoon 15w (megi) Warning Nr 024

From: SIU Weather Processor <[email-masked]>
Date: Mon, 18 Oct 2010 15:54:25 -0500

WTPN31 PGTW 182100
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 15W (MEGI) WARNING NR 024
   01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   181800Z --- NEAR 16.8N 119.3E
     MOVEMENT PAST SIX HOURS - 270 DEGREES AT 11 KTS
     POSITION ACCURATE TO WITHIN 040 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 055 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            055 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 085 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            075 NM SOUTHWEST QUADRANT
                            085 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            120 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            140 NM NORTHWEST QUADRANT
   REPEAT POSIT: 16.8N 119.3E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   190600Z --- 16.7N 117.7E
   MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 080 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            075 NM SOUTHWEST QUADRANT
                            080 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
                            120 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            135 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 285 DEG/ 06 KTS
    ---
   24 HRS, VALID AT:
   191800Z --- 17.0N 116.4E
   MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 080 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            080 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            135 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 315 DEG/ 06 KTS
    ---
   36 HRS, VALID AT:
   200600Z --- 17.8N 115.5E
   MAX SUSTAINED WINDS - 110 KT, GUSTS 135 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 080 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            075 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            130 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 335 DEG/ 05 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   201800Z --- 18.7N 115.1E
   MAX SUSTAINED WINDS - 115 KT, GUSTS 140 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            045 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 075 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            075 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
                            130 NM SOUTHEAST QUADRANT
                            125 NM SOUTHWEST QUADRANT
                            130 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 330 DEG/ 04 KTS
    ---
   72 HRS, VALID AT:
   211800Z --- 20.2N 114.1E
   MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 045 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            045 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            070 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            130 NM SOUTHEAST QUADRANT
                            125 NM SOUTHWEST QUADRANT
                            135 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 310 DEG/ 05 KTS
    ---
   LONG RANGE OUTLOOK:
   NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
   ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
   NEAR 20 KT EACH DAY.
    ---
   96 HRS, VALID AT:
   221800Z --- 21.6N 112.3E
   MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 120 HR POSIT: 305 DEG/ 05 KTS
    ---
   120 HRS, VALID AT:
   231800Z --- 22.9N 110.4E
   MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
182100Z POSITION NEAR 16.8N 118.9E.
TYPHOON (TY) 15W (MEGI), LOCATED APPROXIMATELY 440 NM SOUTHEAST OF
HONG KONG, CHINA, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE PAST 06
HOURS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES THAT TY 15W HAS
TRACKED BACK OVER WATER AND HAS REMAINED WELL-ORGANIZED WITH TIGHTLY-
CURVED BANDING (TCB). A 181509Z TRMM 37 GHZ IMAGE SHOWS A WELL-
DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH A MICROWAVE EYE
FEATURE AND STRONG CONVECTIVE BANDING EVIDENT OVER ALL QUADRANTS.
ANIMATED WATER VAPOR IMAGERY DEPICTS EXCELLENT RADIAL OUTFLOW
ESPECIALLY POLEWARD OUTFLOW, ENHANCED BY STRONG WESTERLY FLOW ACROSS
CENTRAL CHINA. THERE IS GOOD CONFIDENCE IN THE CURRENT POSITION
BASED ON THE TRMM IMAGE AND TCB. THE CURRENT INTENSITY OF 90 KNOTS
IS BASED ON AN AVERAGE OF DVORAK ESTIMATES RANGING FROM 65 TO 115
KNOTS PLUS THE STRONG MICROWAVE SIGNATURE. THE FORECAST TRACK HAS
BEEN ADJUSTED SLIGHTLY BETWEEN TAU 24-72 BASED ON OBSERVED WEAKENING
OF THE WESTERN SUBTROPICAL RIDGE (STR) AND EVIDENCE OF A DEEPENING
SHORTWAVE TROUGH OVER SOUTHEAST CHINA. MODEL GUIDANCE (INCLUDING THE
MAJORITY OF ENSEMBLE DATA) HAS SUBSEQUENTLY TRENDED TOWARD A STAIR-
STEP PATTERN. ALL AVAILABLE DYNAMIC MODELS (ECMWF, UKMO, GFS, JGSM,
NOGAPS, GFDN) PLUS WBAR NOW SUPPORT THIS TRACK AND ARE IN GOOD
AGREEMENT. TY 15W IS EXPECTED TO TURN POLEWARD IN THE NEXT 12-24
HOURS IN RESPONSE TO THE WEAKENING STR AND SHORTWAVE TROUGH. THE
SYSTEM IS FORECAST TO RESUME A WEST-NORTHWESTWARD TRACK AS THE STR
RE-BUILDS NORTH NEAR TAU 72. TY 15W IS EXPECTED TO RE-INTENSIFY OVER
THE NEXT 72 HOURS DUE TO FAVORABLE CONDITIONS AND SHOULD WEAKEN AFTER
TAU 72 DUE TO INCREASING VWS AND LAND INTERACTION NEAR TAU 96.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 181800Z IS 32 FEET.
NEXT WARNINGS AT 190300Z, 190900Z, 191500Z AND 192100Z.//

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