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JTWC/05W/#11/07-06 12Z Prognostic Reasoning
WDPN32 PGTW 061500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 05W (DANAS) WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 23.0N 119.6E
INITIAL INTENSITY: 90 KTS
GEOGRAPHIC REFERENCE: 163 NM SOUTHWEST OF TAIPEI, TAIWAN
MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 11 KTS
SIGNIFICANT WAVE HEIGHT: 30 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
RAPIDLY SHRINKING, 7-10 NM DIAMETER, EYE FEATURE ASSOCIATED WITH
TYPHOON (TY) 05W (DANAS). THE INITIAL POSITION IS DETERMINED WITH
HIGH CONFIDENCE BASED ON THE EYE SIGNATURE APPARENT IN THE EIR
IMAGERY. TY 05W IS CURRENTLY TRACKING NORTHEASTWARD TOWARD THE
WESTERN COASTLINE OF TAIWAN. UNDER THE INFLUENCE OF AN EXTREMELY
FAVORABLE SYNOPTIC ENVIRONMENT, THE SYSTEM HAS UNDERGONE RAPID
INTENSIFICATION - INTENSIFYING BY AT LEAST 30 KTS OVER THE PAST 24
HOURS. DEEP CONVECTIVE BANDING IS WELL ESTABLISHED, PARTICULARLY
ACROSS THE SOUTHERN SEMICIRCLE, WITH SPIRAL BANDS EXTENDING WELL
EASTWARD AND NORTHWARD OF TAIWAN. THE QUICKLY FILLING RAGGED EYE
HAS A TEMPERATURE NEAR OF -30 C, WHILE SURROUNDING OVERSHOOTING
CLOUD TOPS ARE AS COLD AS -82 C. OF NOTE, JUST ONE HOUR PRIOR TO THE
POSITION OF THIS WARNING, AT 061100Z, THE EYE TEMPERATURE RETURNED AN
IMPRESSIVE 2.2 C, WHEN THE SYSTEM LIKELY REACHED PEAK INTENSITY UPWARD
OF 100 KTS. ENVIRONMENTAL ANALYSIS CONFIRMS A HIGHLY FAVORABLE
THERMODYNAMIC AND DYNAMIC SETUP, CHARACTERIZED BY LOW (5-10 KTS)
VERTICAL WIND SHEAR (VWS), VERY WARM SEA SURFACE TEMPERATURES
(29-30 C), AND STRONG, SYMMETRICAL RADIAL OUTFLOW ALOFT. THE ONLY
INHIBITING FACTOR AT THE MOMENT IS PROXIMITY TO LAND AND IMPACT OF
TERRAIN INTERACTION ON THE WIND FIELD ASSOCIATED WITH TY DANAS. THE
INITIAL INTENSITY ESTIMATE OF 90 KTS IS ASSIGNED WITH MEDIUM
CONFIDENCE, BASED ON SUBJECTIVE DVORAK TECHNIQUES AND OBJECTIVE
SATELLITE-BASED INTENSITY ESTIMATES LISTED BELOW.
INITIAL WIND RADII BASIS: PERSISTENCE
CURRENT STEERING MECHANISM: DEEP LAYER NEAR-EQUATORIAL RIDGE (NER)
TO THE SOUTHEAST
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T6.0 - 115 KTS
RJTD: T4.5 - 77 KTS
RCTP: T6.5 - 127 KTS
KNES: T5.5 - 102 KTS
DEMS: T6.0 - 115 KTS
CIMSS SATCON: 87 KTS AT 061101Z
CIMSS ADT: 82 KTS AT 061130Z
CIMSS AIDT: 91 KTS AT 061130Z
CIMSS D-MINT: 74 KTS AT 060731Z
CIMSS D-PRINT: 93 KTS AT 061250Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 5-10 KTS
SST: 29-30 CELSIUS
OUTFLOW: STRONG RADIAL
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
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: TY 05W IS FORECAST TO CONTINUE TRACKING
NORTHEASTWARD THROUGH TAU 36 UNDER THE STEERING INFLUENCE OF A NER
TO THE SOUTHEAST. AS THE SYNOPTIC RIDGE IS REORIENTING ALONG A
SOUTHWEST-TO-NORTHEAST AXIS, IT HAS INDUCED A SLIGHT EASTWARD
ADJUSTMENT TO THE TRACK OF TY DANAS OVER THE LAST 6 HOURS. AS A
RESULT, TY 05W IS EXPECTED TO MAKE LANDFALL ALONG THE SOUTHWESTERN
COAST OF TAIWAN, NEAR THE VICINITY OF QIGU DISTRICT, WITHIN THE NEXT 6
HOURS. AS THE SYSTEM NEARS LANDFALL, ADDITIONAL SHORT-TERM
INTENSIFICATION IS POSSIBLE AND ANTICIPATED. HOWEVER, INTERACTION WITH
THE COMPLEX TOPOGRAPHY OF TAIWAN, INCLUDING THE WESTERN FOOTHILLS AND
THE XUESHAN MOUNTAIN RANGE, IS EXPECTED TO PROMOTE WEAKENING OF THE
CORE STRUCTURE OF TY 05W. ONCE ACROSS THE ISLAND, TY 05W IS FORECAST
TO WEAKEN TO AROUND 65-70 KTS, WHILE MAINTAINING A NORTHEASTWARD
TRAJECTORY THROUGH TAUS 24-36. THEREAFTER, STEERING INFLUENCE IS
EXPECTED TO TRANSFER TO A BUILDING SUBTROPICAL RIDGE (STR) TO THE
NORTH, RESULTING IN A TURN TOWARD THE WEST AND A SECONDARY LANDFALL
OVER MAINLAND CHINA SHORTLY AFTER TAU 48. BEYOND THAT TIMEFRAME, THE
SYSTEM IS EXPECTED TO UNDERGO GRADUAL WEAKENING, WITH FULL DISSIPATION
ANTICIPATED BY OR PRIOR TO TAU 96. INTENSITY FORECAST CONFIDENCE
DURING THE NEXT 24 TO 36 HOURS IS ASSESSED AS MEDIUM, DUE TO
UNCERTAINTY REGARDING THE EXACT TRACK OF THE SYSTEM AND THE MAGNITUDE
OF TERRAIN-INDUCED DISRUPTION ON THE VORTEX AND CONVECTIVE STRUCTURE.
MODEL DISCUSSION: NUMERICAL TRACK MODEL GUIDANCE IS IN STRONG
AGREEMENT THROUGH TAU 24, WITH A CROSS-TRACK SPREAD OF APPROXIMATELY
30 NM. THE MAJORITY OF GLOBAL AND REGIONAL MODELS, INCLUDING THE
MULTI-MODEL CONSENSUS, CONTINUE TO SUPPORT A SCENARIO INVOLVING DIRECT
LANDFALL OVER WESTERN TAIWAN. TRACK FORECAST SPREAD INCREASES BEYOND
TAU 36, PARTICULARLY IN REGARD TO THE TIMING AND ANGLE OF THE
ANTICIPATED WESTWARD TURN, AS WELL AS THE SECONDARY LANDFALL LOCATION
OVER MAINLAND CHINA. THIS IS REFLECTED IN AN EXPANDED CROSS-TRACK
SPREAD OF 150 NM AT THE EXPECTED POINT OF LANDFALL. INTENSITY GUIDANCE
SHOWS FAIR CONSENSUS, WITH ALL MODELS INDICATING THAT TY 05W HAS
ALREADY REACHED PEAK INTENSITY, FOLLOWED BY STEADY WEAKENING THROUGH
THE FORECAST PERIOD. THE ONLY EXCEPTION TO THIS IS COAMPS-TC GUIDANCE
WHICH, INDICATES A MILD INTENSIFICATION BETWEEN TAUS 36 AND 48. THE
JTWC INTENSITY FORECAST IS CARRIED WITH MEDIUM CONFIDENCE, PRIMARILY
DUE TO POTENTIAL MODULATION FROM A TRACK SCENARIO THAT KEEPS THE CORE
STRUCTURE OVER THE WARM WATERS OF THE TAIWAN STRAIT LONGER THAN
CURRENTLY ANTICIPATED, WHICH COULD TEMPORARILY SUSTAIN VORTEX
INTEGRITY, DESPITE IMMINENT LAND INTERACTION.
FORECAST CONFIDENCE:
TRACK 0 - 72 HR: MEDIUM
TRACK 72-120 HR: LOW
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
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楼主: 理可的呆萌呆毛
发表于 2025-7-6 20:50
发表于 2025-7-6 20:51
