簽到天數: 1650 天 [LV.Master]伴壇終老
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老農民版夜神月|2021-10-27 23:59
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JTWC升格C1
WDPN31 PGTW 271500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (MALOU) WARNING NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 21.8N 139.7E
INITIAL INTENSITY: 70 KTS
GEOGRAPHIC REFERENCE: 200 NM SOUTH-SOUTHWEST OF IWO TO
MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 06 KTS
SIGNIFICANT WAVE HEIGHT: 26 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TY 25W CONTINUES TO SLOWLY CONSOLIDATE AND INTENSIFY, THOUGH IT
APPEARS TO BE STRUGGLING TO ESTABLISH A WELL-DEFINED INNER CORE.
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
OVERALL IMPROVED CONVECTIVE SIGNATURE, WITH BANDS OF DEEP
CONVECTION NOW NEARLY SURROUNDING THE ENTIRE 30NM WIDE EYE FEATURE.
THE EASTERN SIDE OF THE EYEWALL HOWEVER IS PARTICULARLY WEAK, AND
OVERALL THE EYEWALL IS RAGGED AND DISCONTINUOUS, AS DEPICTED IN A
271148Z AMSU-B 89GHZ MICROWAVE IMAGE. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON THE ABOVE MENTIONED MICROWAVE
PASS AND THE 30NM RAGGED EYE IN THE EIR. THE INITIAL INTENSITY OF
70 KNOTS IS ASSESSED WITH HIGH CONFIDENCE, EDGED SLIGHTLY HIGHER
THAN THE BULK OF THE AGENCY FIXES IN LIGHT OF A 260820Z SMAP PASS
WHICH SHOWED AN AREA OF 65 TO 75 KNOT WINDS IN THE EASTERN PORTION
OF THE CIRCULATION. OF NOTE, ADT CONTINUES TO RETURN
UNREALISTICALLY LOW ESTIMATES, WHICH IS ALSO DRIVING THE SATCON
LOWER, THUS THE OBJECTIVE ESTIMATES ARE DISCOUNTED IN FAVOR OF THE
SMAP MEASUREMENTS AND SUBJECTIVE ESTIMATES. ADDITIONALLY, THE SMAP
DATA PROVIDED FOR A HIGH CONFIDENCE UPDATE TO THE WIND RADII. THE
ENVIRONMENT REMAINS FAVORABLE FOR DEVELOPMENT, WITH WARM SSTS, LOW
VWS AND VERY STRONG UPPER-LEVEL POLEWARD OUTFLOW INTO THE JET
STREAM TO NORTH.
INITIAL WIND RADII BASIS: SMAP DATA
CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LATER
SUBTROPICAL RIDGE (STR) TO THE EAST.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T4.0 - 65 KTS
RJTD: T3.5 - 55 KTS
KNES: T4.0 - 65 KTS
CIMSS ADT: 39 KTS AT 271130Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 5-10 KTS
SST: 28-29 CELSIUS
OUTFLOW: STRONG POLEWARD
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: HIGH
INITIAL WIND RADII: HIGH
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TY 25W CONTINUES TO TRACK NORTHEASTWARD ALONG
THE WESTERN PERIPHERY OF THE STR. FORWARD SPEED HAS YET TO PICK UP
MUCH JUST YET, HOWEVER THE SYSTEM IS EXPECTED TO BEGIN TO
ACCELERATE WITHIN THE NEXT 12 HOURS, AND WILL CONTINUE TO
STEADILY PICK UP SPEED THROUGH THE DURATION OF THE FORECAST. WHILE
TY 25W HAS NOT CONSOLIDATED AND INTENSIFIED AS QUICKLY AS MIGHT
HAVE BEEN ANTICIPATED IN THE PREVIOUS FORECAST, IT REMAINS
ENSCONCED IN A FAVORABLE ENVIRONMENT AND HAS ABOUT ANOTHER 36 HOURS
IN WHICH TO TAKE ADVANTAGE OF THE FAVORABLE CONDITIONS. THE
COMBINATION OF WARM SSTS, LOW SHEAR AND EXTREMELY STRONG POLEWARD
OUTFLOW IS FORECAST TO PERSIST THROUGH TAU 36, ALLOWING THE SYSTEM
TO REACH A PEAK INTENSITY OF 90 KNOTS AT TAU 36. THE LATEST GLOBAL
MODEL FIELDS AND SHIPS GUIDANCE SHOW SHEAR SHARPLY INCREASING AFTER
TAU 36, REACHING 45 KNOTS BY TAU 48. THE COMBINATION OF HIGH SHEAR,
RAPIDLY COOLING SSTS AND THE ENTRAINMENT OF A WELL-DEFINED WEDGE OF
DRY AIR DIRECTLY INTO THE CORE, WILL ERODE AND WEAKEN THE SYSTEM
AFTER TAU 36. THE SYSTEM IS FORECAST TO BEGIN EXTRA-TROPICAL
TRANSITION (ETT) AROUND TAU 48, AND BY TAU 72 WILL FULLY TRANSITION
TO AN STORM FORCE EXTRATROPICAL LOW PRESSURE SYSTEM.
MODEL DISCUSSION: TRACK GUIDANCE REMAINS IN VERY GOOD CROSS-TRACK
AGREEMENT, WITH LESS THAN 100NM SPREAD EVEN AT TAU 72. ALONG-TRACK
SPREAD IS GOOD THROUGH TAU 48, THEN INCREASES TO 350NM BY TAU 72,
AS WOULD BE EXPECTED WITH A SYSTEM ACCELERATING NORTHEASTWARD WHILE
UNDERGOING ETT. THE JTWC FORECAST TRACK LIES WITHIN THE GUIDANCE
ENVELOPE AND SLIGHTLY SLOWER THAN THE CONSENSUS MEAN THROUGH THE
FORECAST WITH HIGH CONFIDENCE. INTENSITY GUIDANCE SPREAD HAS
INCREASED SINCE THE LAST FORECAST. THOUGH ALL MEMBERS AGREE ON
INTENSIFICATION THROUGH TAU 36, THE BULK OF THE MEMBERS PEAK BELOW
80 KNOTS, WHILE HWRF AND COAMPS-TC CONTINUE TO SHOW NEAR-RAPID
INTENSIFICATION TO A PEAK OF 105 KNOTS BY TAU 36. THE JTWC FORECAST
IS ABOVE ALL BUT THE HWRF AND COAMPS GUIDANCE THROUGH TAU 36, THEN
SLIGHTLY ABOVE THE MEAN THROUGH TAU 72.
FORECAST CONFIDENCE:
TRACK 0 - 72 HR: HIGH
INTENSITY 0 - 72 HR: MEDIUM//
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