Subject: Pacific-NW: 1. Tropical Storm 13w (thirteen) Warning Nr 003

From: SIU Weather Processor <[email-masked]>
Date: Mon, 20 Sep 2010 16:04:05 -0500

WTPN32 PGTW 202100
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL STORM 13W (THIRTEEN) WARNING NR 003
   UPGRADED FROM TROPICAL DEPRESSION 13W
   02 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   201800Z --- NEAR 19.2N 145.2E
     MOVEMENT PAST SIX HOURS - 300 DEGREES AT 06 KTS
     POSITION ACCURATE TO WITHIN 060 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   REPEAT POSIT: 19.2N 145.2E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   210600Z --- 19.8N 144.2E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            055 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 290 DEG/ 05 KTS
    ---
   24 HRS, VALID AT:
   211800Z --- 20.1N 143.2E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            065 NM SOUTHWEST QUADRANT
                            065 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 295 DEG/ 05 KTS
    ---
   36 HRS, VALID AT:
   220600Z --- 20.5N 142.2E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
                            035 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
                            095 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            090 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 300 DEG/ 05 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   221800Z --- 21.0N 141.3E
   MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            025 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
                            110 NM SOUTHEAST QUADRANT
                            110 NM SOUTHWEST QUADRANT
                            115 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 350 DEG/ 08 KTS
    ---
   72 HRS, VALID AT:
   231800Z --- 24.3N 140.7E
   MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT
                            030 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            135 NM SOUTHEAST QUADRANT
                            110 NM SOUTHWEST QUADRANT
                            115 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 025 DEG/ 19 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:
   241800Z --- 31.0N 144.4E
   MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   BECOMING EXTRATROPICAL
   VECTOR TO 120 HR POSIT: 035 DEG/ 29 KTS
    ---
   120 HRS, VALID AT:
   251800Z --- 40.3N 152.7E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   EXTRATROPICAL
    ---
REMARKS:
202100Z POSITION NEAR 19.3N 144.9E.
TROPICAL STORM (TS) 13W (THIRTEEN), LOCATED APPROXIMATELY 235 NM
NORTH OF SAIPAN, HAS TRACKED WEST-NORTHWESTWARD AT 06 KNOTS OVER THE
PAST SIX HOURS. THE POSITION IS BASED ON A 201732Z PGTW SATELLITE
FIX AND A 201546Z AMSR-E PASS. THE CURRENT INTENSITY IS BASED ON A
DVORAK T-NUMBER ESTIMATE OF 2.5 (35 KNOTS) FROM PGTW. TS 13W IS
TRACKING ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL RIDGE TO THE
NORTH. GENERALLY WESTWARD TO WEST-NORTHWESTWARD MOTION IS EXPECTED
TO CONTINUE THROUGH TAU 48 AS THE CURRENT STEERING REGIME PERSISTS.
THEREAFTER, AN APPROACHING MID-LATITUDE TROUGH WILL WEAKEN THE RIDGE
TO THE NORTH, ALLOWING THE CYCLONE TO MAKE A POLEWARD TURN. BETWEEN
TAU 72 AND TAU 120, TS 13W WILL ACCELERATE POLEWARD AND UNDERGO
EXTRATROPICAL TRANSITION IN THE GRADIENT BETWEEN THE MID-LATITUDE
TROUGH TO THE WEST AND A SUBTROPICAL RIDGE TO THE EAST. THE CYCLONE
IS EXPECTED TO INTENSIFY SLOWLY THROUGH TAU 36 AS THE UPPER LEVEL
PATTERN REORIENTS AND EASTERLY VERTICAL WIND SHEAR THAT HAS BEEN
IMPACTING THE SYSTEM BEGINS TO RELAX. AS THE SYSTEM TURNS POLEWARD
BETWEEN TAU 36 AND TAU 72, VERY FAVORABLE UPPER LEVEL OUTFLOW AND
LOW VERTICAL WIND SHEAR WILL ENABLE MORE RAPID DEVELOPMENT. DURING
EXTRATROPICAL TRANSITION BETWEEN TAU 96 AND TAU 120, THE CYCLONE
WILL REMAIN QUITE INTENSE, AS STRONG UPPER LEVEL DIFFLUENCE AND A
SHARP TEMPERATURE GRADIENT ASSOCIATED WITH THE APPROACHING TROUGH
PROVIDE A STRONG BAROCLINIC DEVELOPMENT MECHANISM. THIS FORECAST
LIES SLIGHTLY WEST OF THE PREVIOUS FORECAST IN THE EXTENDED TAUS IN
ANTICIPATION OF A MORE MERIDIONAL STEERING FLOW PATTERN.
ADDITIONALLY, AN EXPECTED IMPROVEMENT IN UPPER LEVEL SUPPORT
NECESSITATED INCREASING THE PEAK INTENSITY TO 95 KNOTS. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 201800Z IS 12 FEET. NEXT WARNINGS AT
210300Z, 210900Z, 211500Z AND 212100Z. REFER TO TROPICAL DEPRESSION
12W (FANAPI) WARNINGS (WTPN31 PGTW) FOR THE FINAL WARNING ON THAT
SYSTEM.//

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