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发表于 2025-8-8 17:22
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JTWC/16W/#06/08-08 06Z Prognostic Reasoning
WDPN32 PGTW 080900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (PODUL) WARNING NR
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 20.6N 145.1E
INITIAL INTENSITY: 40 KTS
GEOGRAPHIC REFERENCE: 414 NM NORTH OF ANDERSEN AFB
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 09 KTS
SIGNIFICANT WAVE HEIGHT: 13 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY
EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) AND A SMALL REGION OF
FLARING CONVECTION POSITIONED JUST TO THE SOUTH OF THE ASSESSED
LLCC. THE LLCC WAS PREVIOUSLY FULLY EXPOSED FOR MOST OF THE DAY,
HAVING ONLY RECENTLY MADE ANOTHER ATTEMPT TO TUCK UNDER THE FLARING
CONVECTION JUST PRIOR TO THE 0600Z HOUR. HOWEVER, JUST LIKE THE
EARLIER ATTEMPTS, THE PRESENCE OF PERSISTENT, MODERATE
NORTHEASTERLY SHEAR AND SOME DRY MID-LEVEL AIR IN THE NORTHERN
FLANK, IS INHIBITING UPSHEAR CONVECTIVE DEVELOPMENT AND HENCE THE
VORTEX CANNOT VERTICALLY ALIGN. A 080355Z AMSR2 37GHZ MICROWAVE
IMAGE SHOWED SHALLOW BANDING FEATURES TO THE NORTH, WITH MORE
ROBUST CONVECTIVE BANDS TO THE SOUTH, WRAPPING INTO A SMALL BUT
DEFINED LLCC. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE
BASED ON THE PARTIALLY OBSCURED LLCC IN THE MSI. THE INITIAL
INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON AN AVERAGING
OF THE AVAILABLE SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES NOTED
ABOVE AND PERSISTENCE WITH EARLIER ASCAT DATA. ENVIRONMENTAL
CONDITIONS ARE FAVORABLE IN THE AGGREGATE, WITH LOW DEEP-LAYER VWS
AND WARM SSTS. ANIMATED WATER VAPOR IMAGERY CONTINUES TO SHOW A
WEAK TUTT-CELL POSITIONED ABOUT 450NM WEST OF TS 16W, BUT OUTFLOW
REMAINS RELATIVELY WEAK TOWARDS THE EQUATOR AND SOME VERY WEAK
WESTWARD OUTFLOW TOWARDS THE TUTT-CELL.
INITIAL WIND RADII BASIS: RELATIVELY DRIER MID-LEVEL AIR DRAPED
AROSS THE NORTHERN FLANK OF THE SYSTEM.
CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED FAR TO THE NORTHEAST.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T3.0 - 45 KTS
RJTD: T2.5 - 35 KTS
RCTP: T3.0 - 45 KTS
KNES: T2.5 - 35 KTS
CIMSS SATCON: 42 KTS AT 072300ZZ
CIMSS ADT: 35 KTS AT 080530Z
CIMSS AIDT: 37 KTS AT 080530Z
CIMSS D-MINT: 30 KTS AT 080632Z
CIMSS D-PRINT: 30 KTS AT 080700Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 10-15 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE EQUATORWARD
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: TROPICAL STORM (TS) 16W IS FORECAST TO
CONTINUE TRACKING NORTHWESTWARD ALONG THE SOUTHWEST SIDE OF THE
STEERING RIDGE POSITIONED TO THE NORTHEAST FOR THE NEXT 24 HOURS.
AFTER TAU 24, THE RIDGE WILL BUILD SOUTHWESTWARD AND MERGE WITH A
WEAKER RIDGE CENTER NEAR OKINAWA, CREATING AN EXTENSIVE RIDGING
COMPLEX THAT WILL EXTEND FROM COASTAL CHINA TO NEAR THE DATELINE.
TS 16W WILL GRADUALLY TURN TO A WESTWARD TRACK TAU 36, TRAVELING
WEST ALONG THE SOUTHERN SIDE OF THIS RIDGE PATTERN THROUGH TAU 72.
AFTER TAU 48, THE SYSTEM REACHES AN INFLECTION POINT, BEYOND WHICH
THE MAIN INFLUENCE ON THE TRACK WILL BE THE INTENSITY OF THE SYSTEM
AT THAT POINT IN THE FORECAST. IF THE SYSTEM CAN INTENSIFY MORE
RAPIDLY IN THE NEXT 48 HOURS, THEN IT WILL FOLLOW A MORE SOUTHERLY
TRACK, SOUTH OF 20N, MOVING WESTWARD UNDER THE DEEP-LAYER RIDGING.
IF THE SYSTEM CANNOT INTENSIFY MUCH IN THE NEXT 48 HOURS, THEN IT
WILL FOLLOW A MUCH MORE NORTHWESTWARD TRACK, MOVING ALONG THE LOW-
TO MID-LEVEL FLOW WHICH IS ALIGNED MORE NORTHWEST-SOUTHEAST THAN
THE DEEP-LAYER MEAN FLOW. THERE IS CONSIDERABLE UNCERTAINTY IN
GLOBAL MODEL AND ENSEMBLE GUIDANCE, WHICH WILL BE DISCUSSED IN MORE
DETAIL IN THE NEXT SECTION. THE SYSTEM IS EXPECTED TO INTENSIFY
SLOWLY THROUGH THE NEXT 48 HOURS, UNDER GENERALLY FAVORABLE
CONDITIONS. THE MAIN LIMITING FACTOR IN THE NEXT 48 HOURS WILL BE
VORTEX MISALIGNMENT AND DRY MID-LEVEL AIR TO THE NORTH. BY TAU 48,
THE SYSTEM IS EXPECTED TO ENCOUNTER STRONG NORTHEASTERLY FLOW
ALOFT, WHICH WILL INCREASE THE SHEAR DRAMATICALLY. IF IT IS
WELL-STRUCTURED AT THAT POINT, IT MAY BE ABLE TO FEND OFF THE WORST
OF THE IMPACTS, BUT IF THE SYSTEM IS STILL ASYMMETRIC AND TILTED,
THE SHEAR WILL IMPACT IT GREATLY AND THE SYSTEM WILL WEAKEN
SIGNIFICANTLY. THE CURRENT FORECAST EXPECTS THE SYSTEM TO BE FAIRLY
WELL-ALIGNED BY TAU 48, AND THUS BE ABLE TO FEND OFF THE SHEAR TO A
DEGREE, RESULTING IN A FLATLINE INTENSITY TREND THROUGH TAU 72.
ASSUMING A MORE SOUTHERLY TRAJECTORY, THE SYSTEM MOVES INTO A MORE
FAVORABLE SHEAR ENVIRONMENT AFTER TAU 96, ALLOWING FOR MODEST
REINTENSIFICATION THROUGH TAU 120.
MODEL DISCUSSION: THE DETERMINISTIC GUIDANCE PACKAGE SHOWS A
PRONOUNCED NORTHWARD SHIFT IN THE TRAJECTORY AFTER TAU 48. THE
NAVGEM, GALWEM, ECMWF, GFS, GEFS AND THE CONSENSUS MEAN ARE TIGHTLY
PACKED ON A NORTHWESTWARD TRACK AFTER TAU 72, TAKING THE SYSTEM
JUST SOUTHWEST OF OKINAWA BY TAU 120. THE JGSM, ECENS MEAN, EC-AIFS
AND SOME OTHER AI MODELS DEPICT A GENERALLY WESTWARD TRACK BELOW
20N THROUGH TAU 120, LEADING TO A CONSIDERABLE AMOUNT OF
CROSS-TRACK UNCERTAINTY EXCEEDING 550NM. BOTH THE GEFS AND ECENS
SHOW A SIMILAR POLEWARD SHIFT IN THE ENSEMBLE MEANS, AS WELL AS
SHARPLY INCREASED UNCERTAINTY IN THE FORECAST TRAJECTORY. GEFS
SHIFTED THE MOST AND EXHIBITS THE MOST UNCERTAINTY, WITH FIVE
MEMBERS SHOWING A WESTWARD TRAJECTORY AND THE REMAINDER OF THE
MEMBERS TURNING NORTHWEST TO VARYING DEGREES INCLUDING SEVERAL
WHICH APPROACH SOUTHERN KYUSHU BY TAU 120. UNCERTAINTY HAS
INCREASED WITH THE ECENS AS WELL, BUT TO A LESSER DEGREE, SHOWING
APPROXIMATELY 10 MEMBERS SHOWING A WESTWARD TRACK BETWEEN 20N-22N,
AND THE REMAINDER OF THE MEMBERS FOLLOWING A MORE NORTHWESTWARD
TRACK AND ABOUT SEVEN TRACKING TOWARDS OR NORTH OF OKINAWA. THE
JTWC FORECAST IS POSITIONED CLOSE TO THE ECENS MEAN AFTER TAU 72,
WITH VERY LOW CONFIDENCE. INTENSITY GUIDANCE IS LIMITED AT THE
MOMENT, WITH ONLY ONE (HAFS-A) MESOSCALE MODEL AVAILABLE. THE
GUIDANCE OVERALL CONTINUES TO COME DOWN IN REFERENCE TO THE PEAK
INTENSITY, AND THE JTWC FORECAST IS POSITIONED NEAR THE DECAY-SHIPS
AND CONSENSUS MEAN THROUGH THE FORECAST PERIOD. HAFS-A IS ABOUT
5-10 KNOTS HIGHER THROUGH MOST OF THE FORECAST. OF NOTE, RICN, FRIA
AND CTR1 RI AIDS ARE TRIPPED, BUT SEEM VERY UNLIKELY AT THIS TIME.
FORECAST CONFIDENCE:
TRACK 00-72 HR: MEDIUM
TRACK 72-120 HR: LOW
INTENSITY 00-72 HR: MEDIUM
INTENSITY 72-120 HR: LOW//
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楼主: ygsj24
发表于 2025-8-8 14:46
