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WDPN31 PGTW 111500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 06W (SIX) WARNING NR
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 25.1N 140.2E
INITIAL INTENSITY: 30 KTS
GEOGRAPHIC REFERENCE: 62 NM WEST-NORTHWEST OF IWO TO
MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 02 KTS
SIGNIFICANT WAVE HEIGHT: 12 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) IMAGERY REVEALS THAT TROPICAL
DEPRESSION (TD) 06W REMAINS QUASI-STATIONARY. THE INITIAL POSITION
IS ASSESSED WITH HIGH CONFIDENCE BASED ON A WELL-DEFINED,
PREDOMINANTLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) APPARENT
IN THE INFRARED IMAGERY, AS WELL AS A 111159Z METOP-B ASCAT PASS.
INCREASING AND MODERATE (15-20 KTS) NORTHWESTERLY VERTICAL WIND
SHEAR (VWS) IS PUSHING THE CENTRAL CONVECTION TOWARDS MODERATELY
STRONG EQUATORWARD OUTFLOW CHANNEL. THE AFOREMENTIONED ASCAT PASS
ALSO REVEALS AN ASYMMETRIC WIND FIELD STRUCTURE, WITH MAXIMUM WINDS
PRESENT THROUGHOUT THE EASTERN SEMICIRCLE OF THE CIRCULATION. THE
SYSTEM CONTINUES TO LACK SUSTAINED DEEP CONVECTION OVER THE LLCC,
LIKELY DUE TO THE SUPPRESSIVE INFLUENCE OF AN UPPER-TROPOSPHERIC
TROUGH POSITIONED DIRECTLY ALOFT. THE INITIAL INTENSITY IS EVALUATED
AT 30 KTS WITH HIGH CONFIDENCE, SUPPORTED BY DVORAK ESTIMATES,
OBJECTIVE SATELLITE-BASED INTENSITY GUIDANCE, AS WELL AS THE 111159Z
ASCAT PASS. ADDITIONAL ENVIRONMENTAL ANALYSIS SUGGESTS MARGINALLY
FAVORABLE CONDITIONS FOR DEVELOPMENT. DEEP-LAYER MOISTURE CONTENT
REMAINS MODERATE TO HIGH, SEA SURFACE TEMPERATURES RANGE FROM 28 TO 29
C, AND THE SYSTEM LIES JUST NORTH OF AN UPPER-LEVEL DIFFLUENT ZONE
ENHANCING EQUATORWARD OUTFLOW.
INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).
CURRENT STEERING MECHANISM: COMPETING STEERING BETWEEN THREE
RIDGING AREAS - TO THE NORTHWEST, SOUTHWEST AND EAST.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T1.5 - 25 KTS
RJTD: T1.0 - 25 KTS
KNES: T1.5 - 25 KTS
CIMSS ADT: 31 KTS AT 111140Z
CIMSS AIDT: 34 KTS AT 111140Z
CIMSS D-PRINT: 28 KTS AT 111230Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 15-20 KTS
SST: 28-29 CELSIUS
OUTFLOW: MODERATE EQUATORWARD
OTHER FACTORS: UPPER LEVEL TROUGH LOCATED OVER THE SYSTEM
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: HIGH
INITIAL WIND RADII: NOT APPLICABLE
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TD 06W REMAINS QUASI-STATIONARY DUE TO ITS
POSITION WITHIN A SYNOPTIC COL REGION, BOUNDED BY SUBTROPICAL
RIDGING TO THE NORTHWEST, SOUTHWEST AND EAST OF THE SYSTEM.
CONSEQUENTLY, THE SYSTEM IS EXPECTED TO EXHIBIT MINIMAL TRANSLATION
OVER THE NEXT 24 HOURS AS THE STEERING PATTERN GRADUALLY EVOLVES.
AROUND TAU 24, THE SUBTROPICAL RIDGE (STR) TO THE EAST IS FORECAST
TO BUILD SIGNIFICANTLY AND ASSUME THE PRIMARY STEERING, FACILITATING A
GRADUAL NORTHWARD ACCELERATION OF THE SYSTEM. INTENSITY IS PROJECTED
TO INCREASE MODESTLY, PEAKING AROUND 50 KTS BY TAU 48. HOWEVER,
FURTHER INTENSIFICATION WILL LIKELY BE CONSTRAINED BY PROGRESSIVE
ENTRAINMENT OF DRY MID-LEVEL AIR INTO THE CORE CIRCULATION. BEYOND TAU
72, THE SYSTEM WILL BEGIN TO INTERACT WITH AN APPROACHING MID-LATITUDE
LONGWAVE TROUGH, LEADING TO INCREASED BAROCLINIC FORCING.
EXTRATROPICAL TRANSITION IS ANTICIPATED TO COMMENCE AROUND TAU 72 AND
COMPLETE BY TAU 96, AS THE SYSTEM BECOMES EMBEDDED WITHIN THE MID-
LATITUDE FLOW.
MODEL DISCUSSION: TRACK GUIDANCE FROM NUMERICAL MODELS HAS IMPROVED
SINCE THE LAST FORECAST AND EXHIBITS FAIR CONSENSUS REGARDING THE
INITIAL QUASI-STATIONARY MOTION, FOLLOWED BY A GENERAL POLEWARD
PROGRESSION AND EVENTUAL NORTHEASTWARD RECURVATURE. CROSS-TRACK
SPREAD AT TAU 36 IS ESTIMATED AT 50 NM, EXPANDING TO 140 NM BY TAU
72. GALWEM AND UKMET SOLUTIONS REMAIN THE OUTLIERS, HOWEVER BOTH
MODELS HAVE NOW JOINED THE REMAINDER OF THE CONSENSUS MEMBERS IN
PROJECTING A NORTH TO NORTHEASTWARD TRACK, WITH THEIR SOLUTIONS
TRACKING FURTHER WEST THAN THE MAIN GROUPING. AS A RESULT, THE JTWC
TRACK FORECAST IS ISSUED WITH MEDIUM CONFIDENCE AND LIES CLOSE TO
THE TIGHTENING MULTI-MODEL CONSENSUS RESULT. INTENSITY GUIDANCE
ALSO DEMONSTRATES GENERAL AGREEMENT, WITH A MODEST INTENSIFICATION
TREND EXPECTED THROUGH TAU 48, FOLLOWED BY WEAKENING DUE TO
ENVIRONMENTAL DEGRADATION. PEAK INTENSITY SPREAD IS STILL ESTIMATED AT
20 KTS, WITH NAVGEM-DRIVEN COAMPS-TC NOW BEING THE MOST CONSERVATIVE
MODEL PROJECTING STRONGEST WINDS OF 40 KTS, AND HAFS REMAINING THE
HIGHEST PROJECTION, WITH 60 KTS MAXIMUM INTENSITY.
FORECAST CONFIDENCE:
TRACK 0 - 72 HR: MEDIUM
TRACK 72-120 HR: MEDIUM
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
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楼主: ygsj24
发表于 2025-7-11 22:00
