Thursday, September 8, 2011

JTWC - Tropical Cyclone Advisory 03 - Tropical Storm Kulap

WTPN31 PGTW 072100
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL STORM 17W (KULAP) WARNING NR 003
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
071800Z --- NEAR 23.8N 135.2E
MOVEMENT PAST SIX HOURS - 335 DEGREES AT 12 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
REPEAT POSIT: 23.8N 135.2E
---
FORECASTS:
12 HRS, VALID AT:
080600Z --- 25.4N 134.0E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 310 DEG/ 10 KTS
---
24 HRS, VALID AT:
081800Z --- 26.6N 132.3E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 310 DEG/ 11 KTS
---
36 HRS, VALID AT:
090600Z --- 28.0N 130.3E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 305 DEG/ 11 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
091800Z --- 29.3N 128.2E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 330 DEG/ 11 KTS
---
72 HRS, VALID AT:
101800Z --- 32.9N 125.6E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 360 DEG/ 10 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
111800Z --- 36.9N 125.5E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
VECTOR TO 120 HR POSIT: 025 DEG/ 13 KTS
---
120 HRS, VALID AT:
121800Z --- 41.6N 128.7E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
---
REMARKS:
072100Z POSITION NEAR 24.2N 134.9E.
TROPICAL STORM (TS) 17W (KULAP), LOCATED APPROXIMATELY 430 NM
EAST-SOUTHEAST OF KADENA AIR BASE, OKINAWA, HAS TRACKED NORTH-
NORTHWESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED
(IR) SATELLITE IMAGERY SHOWS AN EXPOSED LOW LEVEL CIRCULATION CENTER
(LLCC) WITH CONVECTION DISPLACED TO THE SOUTH. IR IMAGERY ALSO
REVEALS SLIGHTLY COOLER CLOUD TOPS OVER THE PAST SIX HOURS. A
07/1830 TRMM 85 GHZ MICROWAVE SATELLITE IMAGE ALSO SHOWS A WELL-
DEFINED LLCC WITH CONVECTION ALONG THE FAR SOUTHERN PERIPHERY. THIS
TRMM IMAGE ALSO INDICATES DRY AIR ALONG THE WESTERN HALF OF THE
SYSTEM, POTENTIALLY INHIBITING CONVECTION IN THIS REGION. A 07/1252Z
PARTIAL ASCAT IMAGE INDICATES TS 17W HAS REMAINED SMALL IN SIZE,
WITH 25-KNOT WIND RADII LESS THAN 120 NM FROM THE CENTER. INITIAL
POSITION IS BASED ON THE AFOREMENTIONED IR AND MICROWAVE IMAGERY,
AND INTENSITY IS BASED ON DVORAK CURRENT INTENSITY ESTIMATES FROM
PGTW, RJTD, AND KNES RANGING FROM 30 TO 45 KNOTS. ANIMATED WATER
VAPOR IMAGERY INDICATES GOOD EQUATORWARD OUTFLOW WITH A DECREASING
POLEWARD OUTFLOW CHANNEL. THE 07/1200Z PGTW UPPER LEVEL STREAMLINE
ANALYSIS REVEALS 17W IS LOCATED BENEATH A RIDGE AXIS IN A REGION OF
FAVORABLE DIFFLUENCE AND LOW (5 TO 15 KNOT) VERTICAL WIND SHEAR
(VWS). TS KULAP'S STEERING INFLUENCE HAS GRADUALLY SHIFTED FROM THE
NEAR EQUATORIAL RIDGE TO THE SOUTHEAST TO THE SUBTROPICAL STEERING
RIDGE TO THE NORTHEAST OF THE SYSTEM. THIS HAS RESULTED IN THE
RECENT TURNING TO THE NORTH-NORTHWEST. THE FORECAST PHILOSOPHY HAS
CHANGED FROM THE PREVIOUS FORECAST. THIS NEW FORECAST PHILOSOPHY IS
PRIMARILY BASED ON THE LOWER THAN EXPECTED INITIAL INTENSITY OF 17W
AND THE SUBSEQUENT STEERING REGIME BASED ON THE EXPECTED SHALLOWER
DEPTH OF THE SYSTEM. TS 17W IS NOW EXPECTED TO CONTINUE TRACKING
ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL STEERING RIDGE TO THE
EAST. AN APPROACHING MID-LATITUDE TROUGH FROM THE WEST SHOULD WEAKEN
THE WESTERN EXTENT, ALLOWING TS 17W TO TRACK POLEWARD, RECURVE OVER
THE KOREAN PENINSULA, AND BECOME EXTRATROPICAL. WITH THE CURRENTLY
EXPOSED LLCC, STEADY INTENSITY OVER THE PAST SIX HOURS, AND
NORTHWARD TRACK INTO A REGION OF HIGHER VERTICAL WIND SHEAR AND
LOWER SEA SURFACE TEMPERATURES, 17W WILL STRUGGLE TO APPROACH
TYPHOON STRENGTH. BETWEEN TAUS 72 AND 96, TS 17W IS EXPECTED TO
INTERACT WITH A BAROCLINIC ZONE AND BEGIN EXTRATROPICAL TRANSITION.
NUMERICAL MODEL GUIDANCE IS SPLIT, WITH EGRR, NOGAPS, AND GFDN
KEEPING 17W ON A STRAIGHT-RUNNING TRACK TOWARD THE WEST AND
DISSIPATING IN EASTERN CHINA. GFS, ECMWF, JGSM, AND WBAR
RECURVE 17W ACROSS THE KOREAN PENINSULA AND FORECAST THE SYSTEM TO
COMPLETE EXTRATROPICAL TRANSITION BY TAU 120. THIS FORECAST IS CLOSE
TO JGSM, ECMWF, AND GFS, WHICH DIFFERS SIGNIFICANTLY FROM THE
PREVIOUS FORECAST AFTER TAU 36. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
071800Z IS 14 FEET. NEXT WARNINGS AT 080300Z, 080900Z, 081500Z AND
082100Z.//

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