000 FXUS63 KMQT 112102 AFDMQT AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 400 PM EST MON FEB 11 2008 .SHORT TERM DISCUSSION (TNGT AND TUE)... WATER VAPOR IMAGERY AND RUC SHOWING A SHORTWAVE OVER EASTERN ONTARIO EMBEDDED IN A LONGWAVE TROUGH OVER EASTERN CANADA. A RIDGE IS OVER THE PACIFIC NORTHWEST AND SOUTHWEST CANADA. A SHORTWAVE IS DIGGING OVER THE NORTHERN PLAINS AS IT SLIDES DOWN THE LEE OF THE WEST COAST RIDGE. SURFACE ANALYSIS DEPICTS A LARGE HIGH OVER THE UPPER GREAT LAKES REGION...WHILE A LOW IS DEEPENING OVER TEXAS. A WARM FRONT IS DEVELOPING OVER THE NORTHERN HIGH PLAINS. MOST OF THE U.P. STATIONS ARE REPORTING TEMPERATURES IN THE SINGLE DIGITS ABOVE ZERO. THE EXCEPTIONS ARE AREAS ALONG THE LAKE SUPERIOR SHORE WHERE TEMPERATURES REACH INTO THE TEENS. THE SURFACE RIDGE WILL REMAIN OVER THE FORECAST AREA THROUGH TUESDAY. WINDS WILL REMAIN FROM THE NORTH TONIGHT. TEMPERATURES DELTA-TS CONTINUE TO BE COOL ENOUGH TO PRODUCE LAKE EFFECT SNOWS OVER AREA PRONE TO LES WITH A NORTH FLOW. THE SHORTWAVE OVER THE NORTHERN PLAINS WILL DEEPEN INTO A TROUGH OVER THE UPPER MISSISSIPPI RIVER VALLEY TONIGHT AND SHIFT INTO THE UPPER MICHIGAN ON TUESDAY. GFS SHOWING WARM AIR ADVECTION AND A SLIGHT INCREASE IN SURFACE DEW POINT OVER THE AREA AS LOW LEVEL MOISTURE OUT OF THE CENTRAL PLAINS PUSH TOWARDS THE UPPER GREAT LAKES. 850MB TEMPERATURES WILL STILL REMAIN AROUND -16C STILL COOL ENOUGH OVER THE LAKES TO PRODUCE SOME LAKE EFFECT SNOW OVER THE SOUTHERN U.P. WHERE THERE WILL BE A SOUTHERLY FLOW. .LONG TERM DISCUSSION (TUE NGT THRU MON)... ON TUE NGT/WED...MOST MODELS HAVE CONTINUED TO TREND WEAKER WITH SHRTWV FCST TO SWING THRU ONTARIO AND ASSOCIATED COLD FROPA INTO THE UPR GRT LKS LATE TUE NGT AND WED DESPITE UPR PATTERN FEATURING HI AMPLITUDE RDG OVER WRN CAN THAT WOULD SUPPORT A MORE STRONGLY DIGGING SYS. GIVEN FVRBL UPR PATTERN...WL BLEND THE GFS WITH THE STRONGER 12Z UKMET FOR THIS SYS. THAT SCENARIO SUGS ASSOCIATED COLD FNT WL APRCH THE WRN ZNS AFT MIDNGT TUE NGT...SO MAINTAINED GOING CHC POPS IN THAT AREA WHERE UPSLOPE FLOW WL TEND TO OFFSET DRYNESS. THEN SOME LGT LES NEAR LK SUP ON WED WITH COLD AIR INTRUSION BEHIND COLD FROPA (H85 TEMPS FCST ON WED RANGES FM -20C TO -24C PER THE UKMET TO -16C TO -20C ON THE GFS). RELATIVELY SHALLOW...DRY NATURE OF COLD AIR INTRUSION AND GENERAL ACYC FLOW IN THE WAKE OF COLD FNT SHOULD LIMIT LES AMTS. EXACT FCST FOR WED NGT AND THU DEPENDS ON COMPLEX INTERACTION BTWN POLAR AND ARCTIC BRANCH DISTURBANCES OVER THE UPR MS VALLEY AND ASSOCIATED SFC LO DVLPMNT/FGEN ON ITS NRN FLANK. PER NCEP GUIDANCE...TRENDED TOWARD THE GFS HANDLING OF THIS INTERACTION BTWN ARCTIC AIR SURGING S FM CAN AND LO PRES DVLPG IN ADVANCE OF POLAR BRANCH SHRTWV. OPTED TO BUMP POPS UP TO HI LIKELY OVER THE SRN TIER LATE WED NGT/THU CLOSER TO LO PRES TRACK TO THE S. SHARP H85-7 FGEN AND UPR DVGC IN THE RRQ OF H3 JET MAX JUST S OF JAMES BAY JUSTIFIES POPS TOWARD THE HI END OF ENSEMBLE GUIDANCE. ELY FLOW OVER NRN LK MI WITH H85 TEMPS ARND -12C WL SUPPORT SOME LK ENHANCEMENT OVER THE SCNTRL WITH HIER QPF THERE. WITH SHARP FGEN TENDING TO ENHANCE LLVL CAD...TENDED TOWARD THE LOWER END OF MOS GUIDANCE FOR TEMPS. TIMING DIFFERENCES AS TO THE DEPARTURE SPEED OF SFC LO ON THU NGT AND TREND TOWARD TRANSITION TO PURE LES. SINCE 12Z GFS HAS TRENDED TOWARD THE 00Z ECMWF WITH FASTER EXIT OF THE LO...TENDED TO FOLLOW THAT TREND WITH FASTER END OF PCPN OVER THE S/TRANSITION TO LES NEAR LK SUP. THEN PERSISTENT LES ON FRI NEAR LK SUP WITH INFLUX OF VERY COLD AIR (GFS SHOWS H85 TEMPS SINKING TO ARND -25C). APRCH OF SHRTWV RDGING/SFC HI ON FRI NGT/SAT WL DIMINISH THESE SHSN. HEDGED TOWARD THE LOWER END OF MOS GUIDANCE FOR SAT MRNG LO TEMPS WITH ARRIVAL OF RDG AXIS/LIGHTER WINDS. NEXT CLIPPER LO DUE TO APRCH LATE SAT AND BRING CHC POPS...HIEST TO THE N...AS CLIPPER TRACKS ACRS LK SUP/ONTARIO ON SUN. TEMPS WL REBOUND TO NEAR NORMAL WITH FAIRLY STRG SW FLOW IN ADVANCE OF THIS SYS...BUT ARRIVAL OF REINFORCING SHRTWV/COLD FNT ON LATE SUN/MON WL TREND TEMPS DOWN AGAIN AND RESTART LES. COORDINATED WITH NCEP/APX/LOT/GRB/DLH. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... CONDITIONS ARE SLOWLY IMPROVING AT KCMX. OCCASIONAL REDUCED VSBYS IS MAINLY DUE TO THE FINE NATURE OF THE SNOW AND IN REALITY NOT MUCH IS ACCUMULATING. WILL CONTINUE WITH IMPROVEMENT THIS AFTERNOON WHEN THE WIND TURNS NORTHERLY. AT SAW...MVFR CONDITIONS SHOULD CONTINUE FOR MUCH OF THE DAY. IN FACT...AS THE WINDS TURN MORE NORTHERLY...SOME OF THE LAKE EFFECT BANDS MAY MOVE ONSHORE ACROSS EASTERN MARQUETTE COUNTY. HOWEVER...AT THE SAME TIME THE INVERSION WILL BE CRASHING SO THE SNOW SHOULD ONLY REDUCE VSBYS TO 3-5SM AT TIMES. ALL SITES SHOULD BECOME VFR LATE THIS EVENING AS THE HIGH BUILDS OVERHEAD. AS A LOW MOVES INTO LOWER MICHIGAN TUESDAY MORNING...A DECK OF LOW CLOUDS AND SOME SNOW SHOULD SPREAD INTO THE KSAW AREA. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WILL LIKELY HAVE A LAND BREEZE TO CONTEND WITH TONIGHT WITH THE HIGH OVERHEAD AND COLD TEMPS ACROSS INLAND AREAS. THE HIGH QUICKLY SHIFTS EAST OF THE LAKES ON TUESDAY...GIVING WAY TO A COLD FRONT APPROACHING FROM THE WEST TUESDAY NIGHT. THE GFS TAKES THE FRONT. WILL KEEP WINDS 15-25 KT WITH THE FRONTAL PASSAGE...BUT IT COULD APPROACH 30 KT WED AFTN. ANOTHER LOW MOVES ALONG THE FRONT AND INTO THE UPPER LAKES BY THU MORNING. NUMEROUS MODEL DIFFERENCES...AND DEPENDING ON THE EXACT TRACK 30KT WIND IS POSSIBLE THU. HEAVY FREEZING SPRAY IS LIKELY OVER AT PORTIONS OF THE LK ON WED NGT THRU SAT AS COLD AIR RETAINS ITS LOCK ON THE UPR GRT LKS. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SHORT TERM DISCUSSION...DLG LONG TERM DISCUSSION...KC AVIATION...DLG MARINE...DLG