Tropical Storm TWENTYSIX Advisory 10月26日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 26W (TWENTYSIX)
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 11.7N 111.0E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 259 NM EAST-NORTHEAST OF HO CHI MINH CITY,
VI
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL DEPRESSION 26W HAS RAPIDLY CONSOLIDATED OVER THE PAST SIX
HOURS, AND REACHED WARNING INTENSITY. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) DEPICTS A WELL DEFINED LOW LEVEL
CIRCULATION CENTER (LLCC), WITH SHALLOW TO MID-LEVEL CONVECTIVE
BANDING WRAPPING INTO THE LLCC. OVER THE PAST COUPLE OF HOURS,
CONVECTION HAS BEGUN TO FLARE OVER THE ASSESSED CENTER, THOUGH THE
OVERALL CONVECTIVE STRUCTURE REMAINS FAIRLY DISORGANIZED. THE
INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE
PARTIALLY EXPOSED LLCC, SPIRAL BAND ANALYSIS AND THE FIRST HINTS OF
A THE WESTERN SIDE OF THE LLCC ON AN ANIMATED RADAR MOSAIC FROM
VIETNAM. THE INITIAL INTENSITY OF 25 KNOTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON A PGTW AND KNES DVORAK CURRENT INTENSITY
ESTIMATE OF T1.5, A 260245Z ASCAT-B SCATTEROMETER PASS SHOWED A
SWATH OF NORTH-SOUTH WINDS OVER 30 KNOTS TRAPPED BETWEEN THE
VIETNAMESE COAST AND THE CENTER, WITH 20-25 KNOTS WRAPPING INTO THE
CENTER ON THE SOUTH AND EASTERN SIDES. A 260600Z SHIP OBSERVATION
APPROXIMATELY 20-NM SOUTHWEST OF THE CENTER INDICATED A 27 KNOT
WIND, PROVIDING ADDITIONAL SUPPORT TO THE INTENSITY. THE
ENVIRONMENT IS FAVORABLE FOR DEVELOPMENT, WITH LOW VWS, MODERATE
POLEWARD AND EQUATORWARD OUTFLOW AND WARM SSTS.
INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).
CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A NORTH-SOUTH
ORIENTED STR EXTENSION OVER THE PHILIPPINES.
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T1.5 - 25 KTS
   KNES: T1.5 - 25 KTS
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: NOT APPLICABLE
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.
FORECAST DISCUSSION: TD 26W WILL CONTINUE TRACKING GENERALLY
WEST-NORTHWEST THROUGH THE FORECAST PERIOD ALONG THE WESTERN
PERIPHERY OF A STR COMPLEX EXTENDING FROM NORTHERN THAILAND TO
HAINAN, AND THEN EXTENDING SOUTHWARD OVER THE PHILIPPINES. THE
SYSTEM IS EXPECTED TO MAKE LANDFALL WITHIN THE NEXT 12 TO 18 HOURS
NEAR NINH HOA, VIETNAM, THEN CONTINUE TRACKING INLAND. WHILE THE
ENVIRONMENT IS FAVORABLE FOR DEVELOPMENT, THE LIMITED TIME OVER
WATER WILL HINDER MUCH IN THE WAY OF INTENSIFICATION, WITH A PEAK
OF 30 KNOTS EXPECTED PRIOR TO LANDFALL. DUE TO FUNNELING EFFECTS
BETWEEN THE COASTLINE AND THE CENTER OF THE SYSTEM, GALE FORCE
WINDS CAN BE EXPECTED WITHIN THE BAND OF HIGH WINDS IN THE WESTERN
QUADRANT OF THE SYSTEM, BUT THE OVERALL INTENSITY IS NOT EXPECTED
TO REACH 35 KNOTS. ONCE ASHORE, THE SYSTEM WILL RAPIDLY WEAKEN AND
ULTIMATELY DISSIPATE OVER NORTHERN CAMBODIA BY TAU 36.
MODEL DISCUSSION: TRACK AND INTENSITY GUIDANCE IS IN GOOD AGREEMENT
THROUGH THE SHORT DURATION OF THE FORECAST PERIOD, LENDING HIGH
CONFIDENCE TO THE JTWC FORECAST.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
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