|
|
JTWC/04W/#27/04-15 12Z Prognostic Reasoning
WDPN31 PGTW 151500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 04W (SINLAKU) WARNING NR 027//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 16.2N 144.6E
INITIAL INTENSITY: 110 KTS
GEOGRAPHIC REFERENCE: 92 NM NORTHWEST OF SAIPAN
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 04 KTS
SIGNIFICANT WAVE HEIGHT: 39 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A LARGE,
POWERFUL TYPHOON WITH AN EYE MEASURING 30 NM IN DIAMETER. THE STORM
MOTION HAS SLOWED FROM 06 KTS TO 04 KTS TOWARDS THE NORTHWEST OVER
THE PAST 06 HOURS, PROLONGING THE DESTRUCTIVE IMPACTS FOR THE
MARIANA ISLANDS. THE CONVECTIVE STRUCTURE HAS IMPROVED SLIGHTLY,
WITH COOLING SURROUNDING CLOUD TOPS AND EXPANDING RADIAL OUTFLOW. A
150801Z WSF-M MWI 37 GHZ IMAGE DEPICTED AN OUTER, 100 NM-WIDE,
CONVECTIVE RING IN WHAT MAY FORESHADOW A SECOND EYEWALL REPLACEMENT
CYCLE (ERC). IN FACT, EIR IMAGERY IS BEGINNING TO SHOW A MOAT
FORMING IN THE NORTHERN SEMICIRCLE, SEPARATING THE EXTREMELY LARGE
RING WITH THE INNER EYEWALL. DEEP CONVECTION HAS FLARED OVER LARGE
SECTIONS OF THE OUTER BAND. A TIMELY 151156Z ASCAT-C PASS CONFIRMS
THAT THE WIND FIELD IS VERY LARGE, WITH GALES EXTENDING OUTWARD TO
OVER 200 NM. GUAM WILL BE SITUATED WITHIN THE 34-KT WIND RADII FOR
AT LEAST THE NEXT 12 HOURS. THE INITIAL POSITION IS ASSESSED WITH
HIGH CONFIDENCE BASED ON THE DEFINED EYE ON EIR IMAGERY. THE
INITIAL INTENSITY IS HELD AT 110 KTS BASED A BLEND OF AGENCY DVORAK
FIXES RANGING FROM T5.5 TO T6.5. THE DVORAK ESTIMATE FROM KNES
INCREASED TO T6.0, AND THE CIMSS AI-RI INDICATES A 25 PERCENT
PROBABILITY OF A 30 KT INCREASE IN 24 HOURS, THOUGH THIS APPEARS
UNLIKELY GIVEN THE SIZE OF THE STORM.
INITIAL WIND RADII BASIS: SCATTEROMETER DATA
CURRENT STEERING MECHANISM: NORTHERN EXTENSION OF A NEAR-EQUATORIAL
RIDGE (NER) TO THE SOUTHEAST
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T5.5 - 102 KTS
RJTD: T6.5 - 127 KTS
RCTP: T6.5 - 127 KTS
KNES: T6.0 - 115 KTS
CIMSS ADT: 94 KTS AT 151140Z
CIMSS AIDT: 100 KTS AT 151140Z
CIMSS D-PRINT: 104 KTS AT 151200Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 0-5 KTS
SST: 28-29 CELSIUS
OUTFLOW: MODERATE RADIAL
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THE INTENSITY FORECAST FOR THE FIRST
36 HOURS HAS BEEN INCREASED.
FORECAST DISCUSSION: TY 04W IS BEING STEERED VERY SLOWLY TO THE
NORTHWEST BY THE NORTHERN EXTENSION OF A NER TO THE SOUTHEAST. THIS
RIDGE HAS EXTENDED TO THE NORTHEAST OF THE SYSTEM, THEREBY
SUPPRESSING THE NORTHWARD MOTION FOR THE MOMENT. THE OVERALL TRACK
HAS SHIFTED 10-20 NM POLEWARD DUE TO THE INITIAL SLOWER SPEED. THE
EXTRA TIME WILL ALLOW THE RIDGE TO THE EAST TO BUILD MORE STRONGLY
AND STEER THE SYSTEM FURTHER TO THE NORTH. A TROUGH PASSING OVER
HONSHU WILL IMMINENTLY ERODE THE FAR NORTHERN EXTENSION OF THE
RIDGE AND ALLOW FOR A SLIGHTLY FASTER TRAJECTORY TOWARDS THE NORTH.
AS THE STORM GAINS LATITUDE, IT WILL COME UNDER THE INFLUENCE OF THE
MID-LATITUDE WESTERLIES, WHICH WILL IMPART AN EASTWARD FORCE ON
DIRECTION OF TRAVEL. TY SINLAKU WILL TURN TOWARDS THE NORTH-NORTHEAST
AT TAU 24 AND THEN NORTHEAST TO EAST-NORTHEAST AT TAU 72, BECOMING
EMBEDDED IN THE WESTERLY FLOW. THE ENVIRONMENT WILL REMAIN FAVORABLE
FOR DEVELOPMENT, CHARACTERIZED BY MINIMAL VWS AND 28 DEGREE CELSIUS
SST. WITH THE SATELLITE PRESENTATION OF TY 04W IMPROVING, THE FORECAST
NOW CALLS FOR SLIGHT INTENSIFICATION TO AT LEAST 115 KTS DURING THE
NEXT 24 HOURS, LIMITED BY POTENTIAL ERC. STEADY TO RAPID WEAKENING
WILL COMMENCE AFTER TAU 24 AS THE STORM TRAVELS OVER SEA SURFACE
TEMPERATURES (SST) OF BELOW 26 DEGREES CELSIUS AND THE VERTICAL WIND
SHEAR (VWS) ASSOCIATED WITH THE WESTERLIES INCREASES TO 20-30 KTS. THE
VWS WILL RAPIDLY ERODE THE WESTERN SIDE OF THE CIRCULATION AND ENABLE
DRY AIR TO RAPIDLY INFILTRATE THE INNER CORE. EXTRATROPICAL TRANSITION
WILL BEGIN AT TAU 96 AND QUICKLY COMPLETE BY TAU 120.
MODEL DISCUSSION: NAVGEM HAS ONCE AGAIN BECOME THE OUTLIER,
DEPICTING A MORE POLEWARD TRAJECTORY FOR THE FIRST 72 HOURS.
NOTABLY, ECMWF HAS ALSO SHIFTED POLEWARD. FOR NOW, THE JTWC TRACK
IS LAID ON TOP OF THE TIGHT GROUPING OF MODELS CONSISTING OF
HAFS-A, GFS, AND COAMPS-TC, ALL OF WHICH ARE AT THE CENTER OF THE
GUIDANCE ENVELOPE. HOWEVER, FUTURE ADJUSTMENTS TO THE NORTH MAY BE
NECESSARY. EXCLUDING NAVGEM, THE CROSS-TRACK SPREAD IS 40 NM AT TAU
24 AND 50 NM AT TAU 48. THE ALONG-TRACK SPREAD IS LOW THROUGH TAU
96. THESE FACTORS GIVE HIGH CONFIDENCE TO THE 72-HR FORECAST TRACK
AND MEDIUM CONFIDENCE THEREAFTER. THE JTWC INTENSITY FORECAST IS
SET ABOVE ALL OF THE RELIABLE INTENSITY AIDS AND IS CLOSEST TO
ECMWF FOR THE FIRST 24 HOURS TO ACCOUNT FOR THE TRENDS OBSERVED IN
THE EIR IMAGERY. THE INTENSITY FORECAST THEN ALIGNS MORE CLOSELY
WITH HAFS-A AND HWRF FROM TAU 48 TO TAU 72. THE EXTRATROPICAL
TRANSITION TO A 55 KT, STORM-FORCE LOW ALIGNS BEST WITH THE GFS
MODEL AT THE END OF THE FORECAST PERIOD.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
TRACK 72-120 HR: MEDIUM
INTENSITY 00-72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
NNNN |
本帖子中包含更多资源
您需要 登录 才可以下载或查看，没有账号？立即注册
×
评分
-
查看全部评分
|
楼主: ygsj24
发表于 2026-4-15 20:24
