Subject: Pacific-NW: 1. Typhoon 15w (megi) Warning Nr 034

From: SIU Weather Processor <[email-masked]>
Date: Thu, 21 Oct 2010 03:32:06 -0500

WTPN31 PGTW 210900
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 15W (MEGI) WARNING NR 034
   01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   210600Z --- NEAR 19.9N 117.6E
     MOVEMENT PAST SIX HOURS - 020 DEGREES AT 05 KTS
     POSITION ACCURATE TO WITHIN 020 NM
     POSITION BASED ON EYE FIXED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 055 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            065 NM SOUTHWEST QUADRANT
                            065 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 085 NM NORTHEAST QUADRANT
                            095 NM SOUTHEAST QUADRANT
                            105 NM SOUTHWEST QUADRANT
                            105 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT
                            175 NM SOUTHEAST QUADRANT
                            180 NM SOUTHWEST QUADRANT
                            180 NM NORTHWEST QUADRANT
   REPEAT POSIT: 19.9N 117.6E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   211800Z --- 20.9N 117.8E
   MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 045 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 075 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            090 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            160 NM SOUTHEAST QUADRANT
                            160 NM SOUTHWEST QUADRANT
                            160 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 005 DEG/ 06 KTS
    ---
   24 HRS, VALID AT:
   220600Z --- 22.0N 117.9E
   MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT
                            035 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            065 NM SOUTHWEST QUADRANT
                            065 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            145 NM SOUTHEAST QUADRANT
                            140 NM SOUTHWEST QUADRANT
                            145 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 350 DEG/ 06 KTS
    ---
   36 HRS, VALID AT:
   221800Z --- 23.2N 117.7E
   MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            125 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 340 DEG/ 06 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   230600Z --- 24.3N 117.2E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 72 HR POSIT: 315 DEG/ 04 KTS
    ---
   72 HRS, VALID AT:
   240600Z --- 25.5N 115.8E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
210900Z POSITION NEAR 20.2N 117.7E.
TYPHOON (TY) 15W (MEGI), LOCATED APPROXIMATELY 245 NM SOUTHEAST OF
HONG KONG, HAS TRACKED NORTHWARD AT 05 KNOTS OVER THE PAST SIX
HOURS. MEGI CONTINUES TO TRACK POLEWARD TOWARDS A WEAKNESS IN THE
SUBTROPICAL STEERING RIDGE. THERE IS HIGH CONFIDENCE IN THE INITIAL
POSITION BASED ON A 40 NM ROUND EYE. PULSING CENTRAL CONVECTION
CONTINUES TO SUPPORT A WIDE RANGE OF DVORAK ESTIMATES AMONG PGTW,
KNES, AND RJTD. IN LIGHT OF THE PREVIOUS FORECAST, THIS FORECAST
BIASES ITS INITIAL INTENSITY TOWARDS THE LOWER END OF THE CURRENT
INTENSITY ESTIMATES. THE SYSTEM WILL SLOWLY WEAKEN AS IT INTERACTS
WITH A STRONG SHEAR GRADIENT ALONG THE SOUTHERN COAST OF CHINA.
HOWEVER, INCREASED POLEWARD OUTFLOW WILL MODERATE THE EFFECTS OF
VERTICAL WIND SHEAR, ALLOWING THE SYSTEM TO MAINTAIN TYPHOON
STRENGTH TILL LANDFALL. LANDFALL IS EXPECTED SHORTLY AFTER TAU 36.
THE LOW LEVEL CIRCULATION CENTER WILL DETACH FROM ITS
(NORTHEASTWARD) SHEARED CONVECTION AND TRACK OVER SOUTHEASTERN CHINA
WHERE IT WILL DISSIPATE. MODEL GUIDANCE CONTINUES TO SUPPORT A
POLEWARD TRACK WITH EGRR AND GFS BEING EASTERN OUTLIERS. THIS
FORECAST DEVIATES LITTLE FROM THE PREVIOUS FORECAST AND LIES CLOSE
TO THE MODEL CONSENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 210600Z
IS 37 FEET. NEXT WARNINGS AT 211500Z, 212100Z, 220300Z AND 220900Z.//

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