WTPN31 PGTW 091500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 11W (MERANTI) WARNING NR 007
UPGRADED FROM TROPICAL STORM 11W
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
091200Z --- NEAR 23.2N 118.9E
MOVEMENT PAST SIX HOURS - 345 DEGREES AT 10 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
REPEAT POSIT: 23.2N 118.9E
---
FORECASTS:
12 HRS, VALID AT:
100000Z --- 25.0N 118.8E
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 24 HR POSIT: 360 DEG/ 12 KTS
---
24 HRS, VALID AT:
101200Z --- 27.4N 118.7E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 36 HR POSIT: 010 DEG/ 10 KTS
---
36 HRS, VALID AT:
110000Z --- 29.3N 119.1E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
091500Z POSITION NEAR 23.6N 118.9E.
TYPHOON (TY) 11W (MERANTI), LOCATED APPROXIMATELY 180 NM SOUTHWEST
OF TAIPEI, TAIWAN, HAS TRACKED NORTH-NORTHWESTWARD AT 10 KNOTS OVER
THE PAST SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 091200Z IS 13
FEET. NEXT WARNINGS AT 092100Z, 100300Z, 100900Z AND 101500Z.//
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WDPN31 PGTW 091500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W WARNING NR 07//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
A. TYPHOON (TY) 11W (MERANTI), LOCATED APPROXIMATELY 180 NM
SOUTHWEST OF TAIPEI, TAIWAN, HAS TRACKED NORTH-NORTHWESTWARD AT 10
KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE
IMAGERY SHOWS A MIDGET SYSTEM WITH A WELL-DEFINED LOW LEVEL
CIRCULATION CENTER (LLCC) AND A 091128Z SSMIS DEPICTS A DEEP
CONVECTIVE MICROWAVE EYE. THE INITIAL POSITION IS BASED ON A RADAR
FIX FROM TAIWAN AND THE AFOREMENTIONED SSMIS IMAGE WITH HIGH
CONFIDENCE. THE INITIAL INTENSITY IS BASED ON THE CONVECTIVE
SIGNATURE AND NOT ON DVORAK ESTIMATES BECAUSE THEY ARE
UNDERESTIMATING THIS MIDGET SYSTEM. UPPER LEVEL ANALYSIS INDICATES
A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL HAS CONTINUED TO
MOVE FARTHER NORTHWESTWARD, WHICH HAS ALLOWED IMPROVED POLEWARD
OUTFLOW AND DECREASED VERTICAL WIND SHEAR (VWS). ADDITIONALLY, TY
11W CONTINUES TO MAINTAIN A GOOD EQUATORWARD OUTFLOW CHANNEL,
ALLOWING IT TO RAPIDLY INTENSIFY.
3. FORECAST REASONING.
A. THE CURRENT INTENSITY HAS INCREASED SIGNIFICANTLY SINCE THE
PREVIOUS FORECAST BECAUSE OF THE DECREASED VWS AND DUAL OUTFLOW
CHANNELS. THE FORECAST TRACK PHILOSOPHY HAS GENERALLY REMAINED THE
SAME EXCEPT FOR AN INCREASE IN TRACK SPEED DUE TO A STRAIGHTER TRACK.
B. TY 11W IS CURRENTLY TRACKING ALONG THE WESTERN PERIPHERY OF A
SUBTROPICAL STEERING RIDGE AND IS EXPECTED TO MAKE LANDFALL IN
APPROXIMATELY 12 HOURS OVER SOUTHEASTERN CHINA. TY 11W SHOULD BEGIN
TO FEEL THE AFFECTS OF LAND AND BEGIN TO WEAKEN BY TAU 12. BY TAU
36, TY MERANTI IS EXPECTED TO DISSIPATE AS A SIGNIFICANT TROPICAL
CYCLONE OVER THE MOUNTAINOUS TERRAIN OF CHINA. NUMERICAL MODEL
GUIDANCE IS IN GOOD AGREEMENT WITH THE EXCEPTION OF THE UKMO MODEL
WHICH ERRONEOUSLY TRACKS THE SYSTEM NORTHEASTWARD TOWARDS TAIWAN
BEFORE TURNING IT NORTHWARD. THIS FORECAST IS SLIGHTLY WEST OF
CONSENSUS TO ACCOUNT FOR THE UKMO MODEL AND IS WITHIN THE TIGHT
MODEL PACKING OF WBAR, ECMWF, NOGAPS, JGSM, AND GFS.//
NNNN
TPPN10 PGTW 091434
A. TYPHOON 11W (MERANTI)
B. 09/1332Z
C. 23.4N
D. 118.8E
E. ONE/MTSAT
F. T4.0/4.0/D1.5/26HRS STT: D1.5/06HRS
G. IR/EIR
H. REMARKS: 05A/PBO IRREG EYE/ANMTN. OFF HOUR DVORAK FOR RAPID
INTENSIFICATION. 5NM DG EYE WITH MG RING AND -.5 EYE ADJ YIELDS
A DT OF 4.0. MET AND PT AGREE. DBO DT.
I. ADDITIONAL POSITIONS:
09/1048Z 23.0N 119.1E AMSU
09/1128Z 23.2N 118.9E SSMS
GATES
