How are you supposed to understand this?
Posted: Tue Sep 30, 2003 11:41 pm
00Z RAOBS/WV LOOP AND RUC ANLSYS SHOW PERSISTENT DEEP UPR TROF CENTERED OVR THE GRT LKS BTWN HI AMPLITUDE RDGS OVR WRN NAMERICA AND THE WRN ATLANTIC. SHRTWV WHICH BROUGHT SCT SHSNRA TO CWA TDAY HAS EXITED TO THE E...AND SKIES CLRD LATE THIS AFTN AS SFC RDGING IN WAKE OF THIS SYS BUILT W-E ACRS CWA. ANOTHER SHRTWV APRNT JUST E OF LK WINNIPEG AND DIGGING SSE PER MOTION OF COLDER CLD TOPS OVR NW ONTARIO. A LO PRES TROF WELL IN ADVANCE OF THIS SHRTWV IS APRCHG THE WRN ZNS AT 00Z AND GENERATING SOME SCT -SHRASN AND EVEN A LTG STRIKE OR TWO. ANOTHER SHARPER SFC TROF APRNTLY TIED WITH LK WINNIPEG SHRTWV APRCHG THE MN ARROWHEAD FM THE N AT 00Z. SFC OBS ACRS NRN MN AND ADJOINING ONTARIO IN ADVANCE OF SHRTWV/UNDER H85 THERMAL TROF (00Z H85 TEMP -7C AT INL) AND WHERE ALL MODELS FCST VIGOROUS DPVA/H7-3 QVECTOR CNVGC SHOWING -SN WITH A FEW IFR VSBYS/ CIGS. 00Z INL SDNG JUST IN ADVANCE OF THE SHRTWV INDICATES CONDITIONALLY UNSTABLE LAPSE RATE SFC-INVRN JUST BLO H6...WITH COOLING EVIDENT ABV H6/WEAKENING OF THE INVRN SINCE 12Z. LLVLS BLO THE INVRN ARE
MARGINALLY MOIST...BUT NOT SO DRY THAT TEMP/MSTR PROFILE LOOKS LIKE AN INVERTED V. 00Z YPL SDNG MORE REPRESENTATIVE OF CYC SIDE OF SHRTWV SHOWS CONDITIONALLY UNSTABLE PROFILE UP TO H4...AND IS MORE MOIST THAN INL SDNG WITH H85 TEMP DOWN TO -9C.
MAIN FCST CONCERN TNGT IS EXTENT/COVG OF PCPN ASSOCIATED WITH APRCHG SHRTWV/SFC TROFS AND POTENTIAL SN ACCUMS. LATEST MODELS ALL SHOW LK WINNIPEG SHRTWV CONTG TO DIG SHARPLY SSE WITH VIGOROUS H7-3 QVECTOR CNVGC OVRSPRDG CWA THIS EVNG BEFORE EXITING TO THE E LATE. HAVE OPTED TO GO WITH LES ADVY FOR INTERIOR GOGEBIC/ONTONAGON/SRN CMX COUNTIES...WHERE 18Z ETA AND TO A LESSER EXTENT RUC MODEL SHOW POTENTIAL FOR PD OF LK ENHANCED SN...WITH MORE PERSISTENT CYC FLOW/LLVL CNVGC ASSOCIATED WITH SFC TROF PASSAGES AND COINCIDENT WITH TIMING OF QVECTOR CNVGC/THERMAL TROF. 18Z ETA FCST WNDS ALSO SUG THAT PERIOD OF PURE LES MAY OCCUR IN THIS AREA EVEN AFTER EXIT OF DYNAMICS AFT 09Z OR SO...WITH ARRIVAL OF -9C H85 TEMPS (AS OBSVD AT YPL) YIELDING A DELTA-T OF 17C. CONSIDERED KEWEENAW ZNS FOR ADVY AS WELL...BUT THINK THAT LLVL WNDS TURNING MORE 320-330 LATER NOT AS FVRBL THERE. PRESENT TRACK OF COLDER CLD TOPS ALSO WOULD TAKE BEST ASSOCIATED UVV JUST TO THE W OF KEWEENAW AS WELL (AND OVER THE FAR W WHERE ADVY POSTED). CONFIDENCE THAT SOME PLACES WL SEE AT LEAST 4 INCHES OF SN INCREASED BY PCPN/LO CIGS OBSVD UPSTREAM... INL/YPL H85 TEMP SVRL DEGREES LWR THAN LAST NGT...PROSPECT FOR MORE VIGOROUS DYNAMICS THAN LAST NGT AS H5 VORT MAX DIGS JUST TO THE SW SO THAT AREA OF CONCERN IS ON CYC SIDE OF SHRTWV...OCCURRENCE LATE AT NGT WHEN DIURNAL HTG WL NOT DISTRUPT POTENTIAL LES BANDS...AND DEEP MSTR/INSTABILITY/WEAK OR ABSENT INVRN OBSVD UPSTREAM. BRUCE CROSSING LAST NGT RPRTD 2 INCHES OF SN WITH WARMER AIR CROSSING THE LK AND MUCH LESS VIGOROUS DYNAMICS. ALTHOUGH REST OF CWA WL SEE SCT (INLAND) OR NMRS (LK SHORE ZNS) SHRASN...LLVL CNVGC FCST TO BE WEAKER AND MORE TRANSIENT. SO NO HEADLINES XCPT FOR 3 ZNS MENTIONED ABV.
HAVE OPTED TO INCLUDE MENTION OF WATERSPOUTS/ISOLD TSRA ACRS ERN LK SUP LATE TNGT/WED AS MODELS SHOW UPR LO DVLPG OVHD...AND H5 TEMPS FALLING CLOSE TO -40C. LIMITING FACTOR FOR WATERSPOUTS WL BE WATER TEMPS GENERALLY AOB 10C. WATERSPOUT CHKLIST SUGS WATER TEMPS SHUD BE AOA 16C FOR WATERSPOUTS...BUT ALL OTHER CHKLIST ITEMS POSITIVE AND CNDN FCST FOR ERN LK SUP INCLUDES WATERSPOUTS.
MARGINALLY MOIST...BUT NOT SO DRY THAT TEMP/MSTR PROFILE LOOKS LIKE AN INVERTED V. 00Z YPL SDNG MORE REPRESENTATIVE OF CYC SIDE OF SHRTWV SHOWS CONDITIONALLY UNSTABLE PROFILE UP TO H4...AND IS MORE MOIST THAN INL SDNG WITH H85 TEMP DOWN TO -9C.
MAIN FCST CONCERN TNGT IS EXTENT/COVG OF PCPN ASSOCIATED WITH APRCHG SHRTWV/SFC TROFS AND POTENTIAL SN ACCUMS. LATEST MODELS ALL SHOW LK WINNIPEG SHRTWV CONTG TO DIG SHARPLY SSE WITH VIGOROUS H7-3 QVECTOR CNVGC OVRSPRDG CWA THIS EVNG BEFORE EXITING TO THE E LATE. HAVE OPTED TO GO WITH LES ADVY FOR INTERIOR GOGEBIC/ONTONAGON/SRN CMX COUNTIES...WHERE 18Z ETA AND TO A LESSER EXTENT RUC MODEL SHOW POTENTIAL FOR PD OF LK ENHANCED SN...WITH MORE PERSISTENT CYC FLOW/LLVL CNVGC ASSOCIATED WITH SFC TROF PASSAGES AND COINCIDENT WITH TIMING OF QVECTOR CNVGC/THERMAL TROF. 18Z ETA FCST WNDS ALSO SUG THAT PERIOD OF PURE LES MAY OCCUR IN THIS AREA EVEN AFTER EXIT OF DYNAMICS AFT 09Z OR SO...WITH ARRIVAL OF -9C H85 TEMPS (AS OBSVD AT YPL) YIELDING A DELTA-T OF 17C. CONSIDERED KEWEENAW ZNS FOR ADVY AS WELL...BUT THINK THAT LLVL WNDS TURNING MORE 320-330 LATER NOT AS FVRBL THERE. PRESENT TRACK OF COLDER CLD TOPS ALSO WOULD TAKE BEST ASSOCIATED UVV JUST TO THE W OF KEWEENAW AS WELL (AND OVER THE FAR W WHERE ADVY POSTED). CONFIDENCE THAT SOME PLACES WL SEE AT LEAST 4 INCHES OF SN INCREASED BY PCPN/LO CIGS OBSVD UPSTREAM... INL/YPL H85 TEMP SVRL DEGREES LWR THAN LAST NGT...PROSPECT FOR MORE VIGOROUS DYNAMICS THAN LAST NGT AS H5 VORT MAX DIGS JUST TO THE SW SO THAT AREA OF CONCERN IS ON CYC SIDE OF SHRTWV...OCCURRENCE LATE AT NGT WHEN DIURNAL HTG WL NOT DISTRUPT POTENTIAL LES BANDS...AND DEEP MSTR/INSTABILITY/WEAK OR ABSENT INVRN OBSVD UPSTREAM. BRUCE CROSSING LAST NGT RPRTD 2 INCHES OF SN WITH WARMER AIR CROSSING THE LK AND MUCH LESS VIGOROUS DYNAMICS. ALTHOUGH REST OF CWA WL SEE SCT (INLAND) OR NMRS (LK SHORE ZNS) SHRASN...LLVL CNVGC FCST TO BE WEAKER AND MORE TRANSIENT. SO NO HEADLINES XCPT FOR 3 ZNS MENTIONED ABV.
HAVE OPTED TO INCLUDE MENTION OF WATERSPOUTS/ISOLD TSRA ACRS ERN LK SUP LATE TNGT/WED AS MODELS SHOW UPR LO DVLPG OVHD...AND H5 TEMPS FALLING CLOSE TO -40C. LIMITING FACTOR FOR WATERSPOUTS WL BE WATER TEMPS GENERALLY AOB 10C. WATERSPOUT CHKLIST SUGS WATER TEMPS SHUD BE AOA 16C FOR WATERSPOUTS...BUT ALL OTHER CHKLIST ITEMS POSITIVE AND CNDN FCST FOR ERN LK SUP INCLUDES WATERSPOUTS.
