Tropical Storm NANMADOL Advisory Fr, 16.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (NANMADOL) WARNING NR 014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 23.8N 135.8E
   INITIAL INTENSITY: 110 KTS
   GEOGRAPHIC REFERENCE: 464 NM EAST-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 36 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A LARGE
ENVELOPE OF DEEP CONVECTION WRAPPING AROUND THE LOW-LEVEL
CIRCULATION CENTER (LLCC), IMAGERY ALSO SHOWS AN EYE THAT HAS BEGUN
TO CLEAR OUT AND WARM OVER THE PAST 6 HOURS. ADDITIONALLY, A
152116Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS WELL-DEFINED FEEDER
BANDS WRAPPING AROUND THE SOUTHERN AND EASTERN PERIPHERY OF THE
CIRCULATION, WITH THE DEEPEST INNER CORE CONVECTION WRAPPING AROUND
THE NORTHERN SEMICIRCLE. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE USING MSI AND FORWARD EXTRAPOLATION OF THE LLCC IN THE
SSMIS PASS. THE INITIAL INTENSITY IS ASSESSED AS 110 KNOTS WITH
MEDIUM CONFIDENCE BASED ON THE IMPROVED SATELLITE DEPICTION, ALONG
WITH THE PGTW DVORAK ESTIMATE OF T6.0, AND THE LATEST CIMSS ADT AND
SATCON VALUES COMING IN AT 110 KNOTS.
INITIAL WIND RADII BASIS: PERSISTENCE
CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE OVER JAPAN
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T6.0 - 115 KTS
   RJTD: T5.5 - 102 KTS
   CIMSS SATCON: 110 KTS AT 160000Z
   CIMSS ADT: 109 KTS AT 152340Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: LOW
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TYPHOON 16W (NANMADOL) APPEARS TO BE RAPIDLY
INTENSIFYING AS THE SYSTEM IS FORECAST TO TRACK NORTHWESTWARD
ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR). THE
CURRENT ENVIRONMENT IS HIGHLY FAVORABLE FOR CONTINUED
INTENSIFICATION, WITH LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS),
WARM (29-30C) SEA SURFACE TEMPERATURES (SSTS), AND MODERATE OUTFLOW
IN ALL QUADRANTS. SEA SURFACE TEMPERATURES ARE FORECAST TO REMAIN
WARM ALONG THE FORECAST TRACK, WITH OVERALL FAVORABLE OUTFLOW OVER
THE NEXT 24 HOURS. THEREFORE, A PEAK INTENSITY OF 130 KNOTS IS
FORECAST TO BE REACHED BY TAU 24 AS IT NEARS THE ISLAND OF MINAMI
DAITO JIMA. BY TAU 36, 16W IS FORECAST TO TRACK OVER AN AREA OF LOW
OCEAN HEAT CONTENT (OHC) THAT WILL LIKELY PUT A CAP ON FURTHER
STRENGTHENING AND WILL LIKELY RESULT IN A DECREASE IN INTENSITY AS
IT CONTINUES NORTHWESTWARD. BY TAU 48, AS THE SYSTEM APPROACHES THE
AXIS OF THE STR, FORWARD MOTION IS FORECAST TO SLOW AS THE SYSTEM
BEGINS TO BE INFLUENCED BY AN APPROACHING UPPER LEVEL TROUGH,
BEFORE RECURVING TOWARD THE NORTHEAST AND MAKING LANDFALL JUST
SOUTH OF SASEBO AT TAU 72. BEYOND TAU 72, THE FORECAST TRACK
CONTINUES NORTHEASTWARD OVER KYUSHU AND HONSHU, WHILE THE SYSTEM
WILL STEADILY WEAKEN DUE TO LAND INTERACTION AND AN INCREASE IN
VERTICAL WIND SHEAR. BETWEEN TAU 96 AND TAU 120, 16W WILL COMPLETE
THE RECURVE AND ACCELERATE TO THE NORTHEAST INTO THE MID-LATITUDE
WESTERLIES WHILE BECOMING EXTRATROPICAL.
MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT THROUGH
TAU 72 WITH ONLY AN 80NM SPREAD IN SOLUTIONS. BETWEEN TAU 96 AND
TAU 120, UNCERTAINTY INCREASES WITH DIFFERENCES IN THE TIMING AND
POSITION OF A POSSIBLE RECURVATURE WITH SOME MODEL TRACKERS DIVERGING.
GIVEN THE UNCERTAINTY IN THE LATER PART OF THE FORECAST, THE JTWC
FORECAST IS CLOSE TO A BLEND OF ECMWF, GFS, ECMWF ENSEMBLE MEAN, AND
GFS ENSEMBLE MEAN. THE JTWC INTENSITY FORECAST IS ABOVE THE
MULTI-MODEL CONSENSUS DUE TO CONTINUED RAPID INTENSIFICATION OVER
THE NEXT 24 HOURS.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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