000 FXUS63 KMQT 311748 AFDMQT AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 148 PM EDT SAT JUL 31 2010 UPDATED AVIATION DISCUSSION FOR 18Z TAFS .SYNOPSIS... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A NW FLOW OVER THE UPPER GREAT LAKES BTWN A TROF OVER ERN CANADA AND A RIDGE OVER THE ROCKIES. A WELL-DEFINED SHORTWAVE MOVING THROUGH ONTARIO AND THE UPPER GREAT LAKES BROUGHT THE HEAVY RAINS TO WEST AND CENTRAL UPPER MI LAST EVENING AND OVERNIGHT. THE HEAVY RAIN THIS MORNING HAS LEAD TO AREAS OF FOG OVER THE GREAT LAKES AND PATCHY FOG OVER INLAND AREAS. && .DISCUSSION... THE SHORTWAVE NOW OVER THE AREA WILL EXIT LAKE SUPERIOR AND UPPER MI LATER THIS MORNING. Q-VECT DIV AND SUBSIDENCE SPREADING IN BEHIND IT SHOULD PROMOTE DRIER CONDITIONS...ALTHOUGH LINGERING HIGH DEWPOINTS IN THE LOWER TO MID 60S AND THE EXISTENCE OF A WEAK SFC BOUNDARY INTERACTING WITH DEVELOPING LAKE BREEZES COULD TRIGGER SOME ISOLATED CONVECTION THIS AFTERNOON. WILL LEAVE IN SLIGHT CHC TO LOW CHC POPS. FOLLOWED A BLEND OF THE BIAS-CORRECTED MAV AND MOS GUIDE WHICH YIELDED HIGHS IN THE 70S WARMEST OVER INLAND AREAS ALONG THE WI BORDER. ANY LINGERING SHRA OVER THE INTERIOR CENTRAL AND EAST WILL DIMINISH EARLY SATURDAY EVENING WITH LOSS OF DAYTIME HEATING. UPPER HEIGHTS WILL BEGIN TO RISE AND SURFACE HIGH PRESSURE WILL BUILD INTO THE AREA. WITH LGT WINDS AND LINGERING LOW LEVEL MOISTURE UNDER SOME MID LVL SUBSIDENCE AND DRYING...PATCHY FOG WILL BE POSSIBLE SAT NIGHT. 5H HEIGHTS WILL CONTINUE TO BUILD ACROSS THE UPPER GREAT LAKES ON SUNDAY AS A S/WV BEGINS TO EJECT OUT OF THE NORTHERN INTERMOUNTAIN WEST AND INTO THE NORTHERN PLAINS. AS THE CENTER OF SFC HIGH PRESSURE SHIFTS EAST OF THE GREAT LAKES...WINDS WILL BECOME SOUTHERLY. NAM DEVELOPS SHOWERS AND UP TO .25 INCH OF QPF OVER CENTRAL COUNTIES WHILE GFS SHOWS A FEW HUNDREDTHS OVER THE SAME GENERAL AREA. LOOKING AT THE DRIER GFS MODEL SNDGS AND THE FACT THAT MID-LVL RDG HEIGHTS WILL BE BUILDING I AM INCLINED TO LEAVE PCPN OUT OF THE SUNDAY FCST AT THIS TIME. EXPECT PARTLY CLOUDY SKIES AND HUMID CONDITIONS WITH HIGHS GENERALLY IN THE LOWER TO MID 80S. SHORTWAVE EMERGING FROM THE NRN ROCKIES AND NRN PLAINS IS PROGGED TO RIDE OVER THE MID-UPR LVL RIDGE INTO THE UPPER GREAT LAKES LATE SUNDAY NIGHT AND MONDAY. EXPECT CONVECTION DEVELOPING AT NOSE OF 30-40 KT LOW-LVL JET AND THETA-E RDG OVER THE NRN PLAINS TO SLIDE INTO UPR MI LATE SUNDAY NIGHT INTO MONDAY. FAVORED HIGHER CHC POPS OVER THE NRN TIER COUNTIES ALONG AND NORTH OF SFC-850 MB WARM FRONT WITH LIKELY POPS OVER THE KEWEENAW PENINSULA AND OVER LAKE SUPERIOR. KEPT IN CHC POPS ACROSS THE FCST AREA MONDAY NIGHT AS SLOW-MOVING COLD FRONT WITH SYSTEM ADVANCES EAST ACROSS THE REGION. MLCAPE VALUES INCREASING TO 1000-1500 J/KG AND DEEP LYR SHEAR INCREASING TO 40-45 KT BY MONDAY COULD RESULT IN SEVERE STORM DEVELOPMENT WITH BOWING SEGMENTS AND DAMAGING WINDS THE MAIN THREAT. SPC CONVECTIVE OUTLOOK HAS ENTIRE CWA IN SLIGHT RISK FOR DAY 3. MODELS INDICATE COLD FRONT CLEARING THE AREA BY TUESDAY WITH DRIER AIR AND HIGH PRESSURE RIDGING INTO THE AREA BY MID-WEEK. HIGH TEMPS WILL CONTINUE TO RUN SEVERAL DEGREES ABOVE NORMAL INTO MID-WEEK. && .AVIATION /FOR THE 18Z TAF ISSUANCE/... EXPECT MAINLY MVFR CIGS WITH SCT SHRA TO IMPACT KSAW INTO LATE AFTN...WITH SKIES SLOWLY CLEARING AT KCMX. LINGERING LOW-LEVEL MOISTURE WITH DRYING ALOFT SHOULD RESULT IN FOG TONIGHT AT BOTH SITES. HAVE FCST LIFR CONDITIONS AT KSAW WITH IDEAL RADIATIONAL COOLING AND WITH RECENT RAINFALL THIS AFTN/EARLY EVENING. AT KCMX...HAVE WENT WITH MVFR CONDITIONS AS WINDS ARE EXPECTED TO REMAIN MORE WRLY. LOCAL CLIMATOLOGY AT KCMX FOR JUL/AUG INDICATES THAT IF WINDS SET UP MORE SE/E TONIGHT...THEN CONDITIONS COULD GO MUCH LOWER. CONDITIONS TRANSITION BACK TO VFR BY MID MORNING SUNDAY AT BOTH SITES. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FCST ISSUANCE/... WITH HIGH PRES GENERALLY DOMINATING THE UPPER GREAT LAKES THROUGH SUNDAY AFTERNOON...ASSOCIATED WEAK PRESSURE GRADIENT WILL KEEP WINDS BELOW 20KT. A LOW PRESSURE TROUGH EXPECTED TO MOVE ACROSS THE UPPER GREAT LAKES MONDAY NIGHT WILL RESULT IN A PERIOD OF STRONGER SOUTH TO SOUTHWEST WINDS OF 15-25KT LATE SUN NIGHT THROUGH MONDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...VOSS DISCUSSION...VOSS AVIATION...JLA MARINE...DLG
NWS MQT Office Area Forecast Discussion
Courtesy National Weather Service