Subject: Pacific-NW: 1. Super Typhoon 15w (megi) Warning Nr 020

From: SIU Weather Processor <[email-masked]>
Date: Sun, 17 Oct 2010 15:45:05 -0500

WTPN31 PGTW 172100
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. SUPER TYPHOON 15W (MEGI) WARNING NR 020
   01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   171800Z --- NEAR 17.6N 124.2E
     MOVEMENT PAST SIX HOURS - 240 DEGREES AT 10 KTS
     POSITION ACCURATE TO WITHIN 025 NM
     POSITION BASED ON EYE FIXED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 155 KT, GUSTS 190 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 055 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            080 NM SOUTHWEST QUADRANT
                            095 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT
                            110 NM SOUTHEAST QUADRANT
                            130 NM SOUTHWEST QUADRANT
                            150 NM NORTHWEST QUADRANT
   REPEAT POSIT: 17.6N 124.2E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   180600Z --- 17.2N 122.1E
   MAX SUSTAINED WINDS - 145 KT, GUSTS 175 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 090 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            075 NM SOUTHWEST QUADRANT
                            090 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT
                            115 NM SOUTHEAST QUADRANT
                            135 NM SOUTHWEST QUADRANT
                            150 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 260 DEG/ 11 KTS
    ---
   24 HRS, VALID AT:
   181800Z --- 16.8N 119.9E
   MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT
                            030 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 075 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            080 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            140 NM SOUTHWEST QUADRANT
                            155 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 265 DEG/ 08 KTS
    ---
   36 HRS, VALID AT:
   190600Z --- 16.7N 118.2E
   MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT
                            035 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            045 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 075 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            075 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            135 NM SOUTHWEST QUADRANT
                            145 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 280 DEG/ 06 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   191800Z --- 16.9N 116.9E
   MAX SUSTAINED WINDS - 110 KT, GUSTS 135 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            045 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 075 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            075 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            130 NM SOUTHWEST QUADRANT
                            140 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 285 DEG/ 04 KTS
    ---
   72 HRS, VALID AT:
   201800Z --- 17.4N 115.2E
   MAX SUSTAINED WINDS - 115 KT, GUSTS 140 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 - 075 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            075 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            130 NM SOUTHWEST QUADRANT
                            135 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 300 DEG/ 04 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:
   211800Z --- 18.2N 113.8E
   MAX SUSTAINED WINDS - 115 KT, GUSTS 140 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 120 HR POSIT: 320 DEG/ 05 KTS
    ---
   120 HRS, VALID AT:
   221800Z --- 19.8N 112.4E
   MAX SUSTAINED WINDS - 110 KT, GUSTS 135 KT
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
REMARKS:
172100Z POSITION NEAR 17.5N 123.7E.
SUPER TYPHOON (STY) 15W (MEGI) LOCATED APPROXIMATELY 255 NM
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-SOUTHWESTWARD AT
10 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE
IMAGERY DEPICTS A WELL-DEFINED 25 NM DIAMETER EYE WITH A CONCENTRIC
EYE WALL AND EXCELLENT RADIAL OUTFLOW. THERE IS HIGH CONFIDENCE IN
THE CURRENT POSITION BASED ON COINCIDENT EYE FIXES FROM PGTW AND
RJTD AT 17/18Z. STY MEGI APPEARS TO HAVE REACHED A PEAK INTENSITY OF
160 TO 165 KNOTS BETWEEN 17/12Z AND 17/18Z, BASED ON 171115Z AND
171206Z AIRCRAFT VORTEX MESSAGES INDICATING 163 KNOT MAXIMUM SURFACE
WINDS AND A MEAN SEA LEVEL PRESSURE OF 893 MB. THE CURRENT INTENSITY
IS BASED ON DVORAK ESTIMATES OF 155 KNOTS FROM PGTW AND RJTD AND
REFLECTS A SLIGHT WEAKENING DUE TO INITIAL INTERACTION OF THE
WESTERN EXTENT OF THE SYSTEM WITH THE EASTERN COAST OF LUZON.
POLEWARD AND EQUATORWARD OUTFLOW HAVE SUSTAINED AHEAD OF A
TRANSITORY MID-LATITUDE TROUGH AND INTO A TUTT CELL TO THE EAST OF
THE SYSTEM, RESPECTIVELY. STY MEGI IS FORECAST TO MAKE LANDFALL NEAR
CAGAYAN AND ISABELA PROVINCES IN NORTHERN LUZON AND WEAKEN TO
TYPHOON INTENSITY AS IT CROSSES THE CORDILLERA MOUNTAIN RANGE. STY
15W IS EXPECTED TO RE-EMERGE INTO THE SOUTH CHINA SEA NEAR TAU 24
AND RE-INTENSIFY AS IT TRACKS TOWARD SOUTHERN CHINA. NUMERICAL MODEL
GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 36, WITH THE EXCEPTION OF
GFS WHICH ERRONEOUSLY RE-CURVES THE SYSTEM TOWARD TAIWAN. AFTER TAU
36, THERE IS SOME SPREAD IN THE MODEL TRACKS BASED ON THE TIMING IN
WHICH THE SUBTROPICAL STEERING RIDGE IS EXPECTED TO WEAKEN. THIS
FORECAST IS CLOSE TO MODEL CONSENSUS THROUGH TAU 36, BUT IS SLIGHTLY
SOUTH OF CONSENSUS IN THE LATER TAUS, FAVORING THE MORE CONSISTENT
UKMO, ECMWF, AND JGSM MODEL TRACKERS. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 171800Z IS 38 FEET. NEXT WARNINGS AT 180300Z, 180900Z,
181500Z AND 182100Z.//

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