簽到天數: 1650 天 [LV.Master]伴壇終老
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老農民版夜神月|2021-12-14 01:08
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JTWC判定稍早有略微減弱,目前由06Z的70KT略降為C1下限65KTWDPS31 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03P (RUBY) WARNING NR
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 19.2S 162.3E
INITIAL INTENSITY: 65 KTS
GEOGRAPHIC REFERENCE: 275 NM NORTHWEST OF NOUMEA, NEW CALEDONIA
MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 17 KTS
SIGNIFICANT WAVE HEIGHT: 17 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS FLARING
CONVECTION OVER AN OBSCURED LOW-LEVEL CIRCULATION CENTER (LLCC).
CONVECTIVE BANDING OVER THE EASTERN SEMICIRCLE HAS BECOME MORE
FRAGMENTED OVER THE PAST SIX HOURS. A 130802Z SSMIS 91GHZ MICROWAVE
IMAGE REVEALS DEEP CONVECTIVE BANDING WRAPPING INTO A DEFINED,
RAGGED LLCC WITH SHALLOW BANDING EXPOSED OVER THE WESTERN
SEMICIRCLE. THIS RECENT DETERIORATION IS LIKELY DUE TO PERSISTENT
WESTERLY VERTICAL WIND SHEAR AND MID- TO UPPER-LEVEL DRY AIR
ENTRAINMENT. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON A 131024Z ASCAT-B BULLSEYE IMAGE, WHICH SHOWS 45-50 KNOT
WINDS. THE INITIAL INTENSITY OF 65 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON DVORAK CURRENT INTENSITY ESTIMATES, HOWEVER,
DATA T ESTIMATES HAVE DECREASED STEADILY TO T3.0-3.5 (45-55 KNOTS).
INITIAL WIND RADII BASIS: SCATTEROMETER DATA
CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE EAST.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: 4.0 - 65 KTS
KNES: 4.0 - 65 KTS
CIMSS SATCON: 69 KTS AT 132307Z
CIMSS ADT: 82 KTS AT 130840Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 10-15 KTS
SST: 28-29 CELSIUS
OUTFLOW: STRONG POLEWARD
OTHER FACTORS: DRY AIR ENTRAINMENT
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: HIGH
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TC 03P WILL TRACK EAST-SOUTHEASTWARD TO
SOUTHEASTWARD THROUGH THE FORECAST PERIOD ALONG THE SOUTHWESTERN
PERIPHERY OF A DEEP-LAYERED STR. HOWEVER, THE SYSTEM WILL
ACCELERATE AFTER TAU 12 WITHIN ENHANCED FLOW BETWEEN THE
AFOREMENTIONED STR AND A DEEP, HIGH AMPLITUDE TROUGH. THIS STEERING
PATTERN IS CLASSIFIED AS A HIGH AMPLITUDE PATTERN AND IS COMMON
EAST OF AUSTRALIA, AND GENERALLY PRODUCES FASTER-THAN-CLIMATOLOGICAL
TRACK SPEEDS WITH HIGH CONFIDENCE TRACK CONFIDENCE. TC 03P WILL RE-
INTENSIFY BY TAU 12 TO A PEAK INTENSITY OF 70 KNOTS. BY TAU 36, THE
SYSTEM WILL BEGIN TO INTERACT WITH THE SUBTROPICAL WESTERLIES AND
TRACK OVER COOLER SST (25C). BY TAU 72, TC 03P WILL ENCOUNTER STRONG
VERTICAL WIND SHEAR (35-50 KNOTS) WITH SIGNIFICANTLY COOLER SST (22-
19C). THIS WILL SERVE TO RAPIDLY WEAKEN THE CONVECTIVE STRUCTURE AND
LEAD TO SUBTROPICAL TRANSITION. HOWEVER, THE SYSTEM WILL REMAIN A
STORM-FORCE SUBTROPICAL LOW AS IT APPROACHES NEW ZEALAND.
MODEL DISCUSSION: AS MENTIONED EARLIER, THE HIGH AMPLITUDE PATTERN
TYPICALLY PRODUCES TIGHTLY-GROUPED FORECAST GUIDANCE AND,
CONSEQUENTLY, HIGH CONFIDENCE FORECAST TRACKS. THIS SYSTEM IS NO
EXCEPTION WITH A 70-80NM SPREAD IN SOLUTIONS THROUGH 48.
ADDITIONALLY, THE 130000Z ECMWF ENSEMBLE (EPS) ALSO INDICATES A
TIGHT GROUPING OF ENSEMBLE MEMBERS AND A NARROW CONE OF HIGH STRIKE
PROBABILITY OVER AND JUST NORTH OF NEW CALEDONIA EXTENDING
SOUTHEASTWARD. THE JTWC INTENSITY FORECAST IS MORE UNCERTAIN WITH
RELIABLE INTENSITY GUIDANCE RANGING FROM 50-70 KNOTS WITHIN THE
NEXT 24 HOURS. AFTER TAU 48, THE INTENSITY GUIDANCE COMES INTO
BETTER ALIGNMENT WITH A STEADY WEAKENING TREND THROUGH TAU 72. THE
JTWC INTENSITY FORECAST IS CONSERVATIVELY PLACED CLOSER TO THE HWRF
WITH A SLIGHT INTENSIFICATION EXPECTED OVER THE NEXT 12 HOURS.
FORECAST CONFIDENCE:
TRACK 0 - 72 HR: HIGH
INTENSITY 0 - 72 HR: MEDIUM//
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