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老農民版夜神月|2021-12-8 07:45
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本帖最後由 老農民版夜神月 於 2021-12-8 07:47 編輯
JTWC開始發報
WDXS31 PGTW 072100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02S (TERATAI)
WARNING NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 11.8S 106.5E
INITIAL INTENSITY: 35 KTS
GEOGRAPHIC REFERENCE: 766 NM NORTHWEST OF LEARMONTH, AUSTRALIA
MOVEMENT PAST 6 HOURS: SOUTHWARD AT 04 KTS
SIGNIFICANT WAVE HEIGHT: 12 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS FLARING DEEP
CONVECTION SHEARED TO THE WEST OF A PARTIALLY EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC). THE CONVECTION AT ANALYSIS TIME WAS
HIGHLY SYMMETRICAL AND LOCATED IN CLOSE VICINITY TO THE LLCC,
HOWEVER SUBSEQUENT IMAGERY INDICATES A VERY SHARP UPSHEAR EDGE OF
THE CIRRUS SHIELD AND AN INCREASINGLY RAGGED, DISORGANIZED
STRUCTURE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE
BASED ON THE PARTIALLY EXPOSED LLCC IN ANIMATED SHORTWAVE INFRARED
IMAGERY. WHILE THE CONVECTIVE STRUCTURE IS NOT ALL THAT IMPRESSIVE,
THE LOW LEVEL WIND FIELD AS MEASURED BY A SERIES OF SCATTEROMETER
PASSES BETWEEN 071145Z AND 111516Z SHOWING 30-35 KNOT WINDS
SURROUNDING THE LLCC. THUS THE INITIAL INTENSITY IS ASSESSED AT 35
KNOTS, HEDGED ABOVE THE PGTW T1.5 (25-30 KTS) DVORAK CURRENT
INTENSITY ESTIMATE FROM PGTW, WHICH IS BASED SOLELY UPON THE
DISORGANIZED CONVECTIVE STRUCTURE. THE SYSTEM IS MOVING SOUTHWARD
ALONG THE NORTHWESTERN PERIPHERY OF A LOW TO MID-LEVEL SUBTROPICAL
RIDGE (STR) TO THE SOUTHEAST. THE ENVIRONMENT IS SOMEWHAT MARGINAL,
WITH WARM (28-29C) SSTS AND GOOD POLEWARD OUTFLOW OFFSETTING
MODERATE VWS.
INITIAL WIND RADII BASIS: SCATTEROMETER DATA
CURRENT STEERING MECHANISM: NORTHWEST PERIPHERY OF STR CENTERED TO
THE SOUTHEAST
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T1.5 - 25 KTS
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 15-25 KTS
SST: 28-29 CELSIUS
OUTFLOW: MODERATE TO HIGH EQUATORWARD
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: HIGH
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY FOR THE RE-START OF
WARNINGS ON TC 02S.
FORECAST DISCUSSION: TROPICAL CYCLONE 02S (TERATAI) HAS RE-
INTENSIFIED TO TROPICAL STORM STRENGTH AND THUS JTWC IS RECOMMENCING
ISSUANCE OF TROPICAL CYCLONE WARNINGS. TC 02S IS FORECAST TO TURN
SOUTHWESTWARD OVER THE NEXT 12 HOURS, THEN CONTINUE TRACKING
SOUTHWESTWARD THROUGH THE FORECAST PERIOD ALONG THE NORTHWESTERN
PERIPHERY OF A LOW TO MID-LEVEL STR TO THE SOUTHEAST. BETWEEN
071200Z AND 071800Z, THE UPPER-LEVEL SHEAR ENVIRONMENT WEAKENED TO
THE POINT WHERE THE CORE OF THE SYSTEM WAS ABLE TO STACK VERTICALLY,
AND CONVECTION FLARED OVER TOP OF THE LLCC. SUBSEQUENTLY, SHEAR HAS
INCREASED ONCE AGAIN AS EVIDENCED BY THE VERY SHARP UPSHEAR
(EASTERN) EDGE OF THE CONVECTIVE MASS, AND THE EXPOSED LLCC. GLOBAL
MODEL FIELDS SUGGEST THE SHEAR WILL AVERAGE ABOUT 15 KNOTS FOR THE
NEXT 24-48 HOURS. HOWEVER, THIS MODERATE SHEAR WILL COMPETE WITH,
AND BE OFFSET BY, RELATIVELY GOOD POLEWARD OUTFLOW, RESULTING IN A
STEADY INTENSITY THROUGH TAU 36. BEGINNING AROUND TAU 36 THE OUTFLOW
PATTERN SHIFTS AND UPPER-LEVEL FLOW BECOMES CONVERGENT OVER TOP OF
THE SYSTEM AND THE MID-ATMOSPHERE BEGINS TO DRY OUT, LEADING TO
WEAKENING AND DISSIPATION NO LATER THAN TAU 48.
MODEL DISCUSSION: NUMERICAL TRACK GUIDANCE IS IN GOOD AGREEMENT,
WITH ALL CONSENSUS MEMBERS AGREEING ON THE SOUTHWESTWARD TRACK,
ENSCONCED WITHIN A 100-120NM ENVELOPE, LENDING HIGH CONFIDENCE TO
THE JTWC FORECAST TRACK. INTENSITY GUIDANCE IS IN OVERALL GOOD
AGREEMENT, WITH THE MAJORITY OF CONSENSUS MEMBERS INDICATING A FLAT
INTENSITY TREND, LENDING HIGH CONFIDENCE TO THE JTWC INTENSITY
FORECAST.
FORECAST CONFIDENCE:
TRACK 0 - 72 HR: HIGH
INTENSITY 0 - 72 HR: HIGH//
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