663 FXUS63 KMQT 250034 AAA AFDMQT AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 834 PM EDT TUE SEP 24 2013 .UPDATE... ISSUED AT 833 PM EDT TUE SEP 24 2013 QUIET NIGHT UNDERWAY AS HIGH PRESSURE IS OVERHEAD. NO BIG CHANGES TO GOING FORECAST. MAIN ISSUE OVERNIGHT TONIGHT THROUGH AROUND DAYBREAK WEDNESDAY IS EXTENT OF DENSE FOG. DWPNTS STAYED MAINLY IN THE UPR 40S TO AROUND 50 DEGREES THIS AFTN AND WITH WINDS BECOMING LIGHT TONIGHT...EXPECT TEMPS TO FALL WELL BELOW THE CROSSOVER TEMPS INTO THE LOWER 40S OR MAYBE EVEN UPPER 30S LATE TONIGHT. FROST RISK WILL BE MINIMAL...CONFINED TO INTERIOR EAST CWA...SINCE THE DWPNTS ARE WELL ABOVE FREEZING. FOG SHOULD BE PRETTY WIDESPREAD...BUT NOT SURE ON THE COVERAGE OF DENSE FOG. TWEAKED GRIDS TO ADD SOME DENSE FOG WORDING AND WILL RE-ISSUE THE SPECIAL WEATHER STATEMENT. GREATEST CHANCE OF SEEING VSBY LESS THAN ONE-QUARTER MILE WOULD BE ACROSS IRON AND DICKINSON COUNTIES AND ALSO AFFECTING AREAS FROM SOUTHERN BARAGA COUNTY INTO WESTERN MARQUETTE COUNTY. IF THE DENSE FOG ENDS UP MORE WIDESPREAD THAN EXPECTED...MID SHIFT MAY NEED TO PUT OUT A SHORT DURATION DENSE FOG ADVY FOR THE MORNING COMMUTE TO WORK AND SCHOOL. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 336 PM EDT TUE SEP 24 2013 MILD AND DRY CONDITIONS WILL PERSIST THROUGH WEDNESDAY. THE MAIN FOCUS OF THE PERIOD WILL BE THE POTENTIAL FOR WIDESPREAD FOG DEVELOPMENT TONIGHT...MAINLY ACROSS THE INTERIOR CENTRAL AND EAST. TONIGHT...UPPER MI REMAINS UNDER THE INFLUENCE OF THE WESTERN EDGE OF A SHARP MID-LEVEL RIDGE...WHICH IS SITUATED BETWEEN A DECAYING TROUGH MOVING INTO THE UPPER AND MID MS VALLEY...AND A SLIGHTLY RETROGRADING CLOSED LOW NEAR MAINE. MEANWHILE...NEARLY STATIONARY HIGH PRESSURE IS OVER FAR EASTERN ONTARIO. MINIMAL PATTERN CHANGES OVER THE NEXT DAY SHOULD RESULT IN A GENERALLY PERSISTENT FORECAST FROM THE WEATHER TODAY. THE MID-LEVEL TROUGH NEARING THE MS VALLEY IS EXPECTED TO GRADUALLY WEAKEN...WITH A BROAD AND WEAK CUT-OFF LOW FORMING ALONG THE SOUTHERN EXTENT ACROSS THE LOWER OHIO VALLEY. THE REST OF THE TROUGH WILL QUICKLY LIFT NE AND POSSIBLY BRUSH THE WESTERN CWA WITH SOME DECAYING CIRRUS THROUGH WEDNESDAY. FOG DEVELOPMENT TONIGHT CONTINUES TO BE THE MAIN FORECAST CHALLENGE ATTM. WHILE THE MID-LEVEL RIDGE SLOWLY TRACKS EAST...SFC WINDS WILL WEAKEN AND BECOME NEARLY CALM AS THE SFC HIGH BUILDS WESTWARD TO OVER THE EASTERN CWA BY WEDNESDAY MORNING. DRY AIR ABOVE A LOW-LEVEL INVERSION WILL BE PRESENT AS INDICATED BY PWAT VALUES OF 0.4-0.5 INCHES ON FORECAST SOUNDINGS. LIGHT SE WINDS OFF LAKE MI SHOULD ASSIST WITH SOME INITIAL UPSLOPE/MOISTENING ACROSS THE CENTRAL CWA THIS EVENING. A PERSISTENT STRATOCUMULUS DECK ALONG GREEN BAY AND LAKE MI TODAY IS INDICATIVE OF THE LOW-LEVEL MOISTURE ALREADY AVAILABLE. EVEN MORE SO...CROSS-OVER TEMPS WILL ONLY BE AS LOW AS THE UPPER 40S. WITH LOWS EXPECTED TO GRADUALLY DROP TO THE LOW 40S OVERNIGHT...FOG SHOULD BEGIN DEVELOPING BY 06Z AND BECOME MOST WIDESPREAD AROUND SUNRISE. THE BEST CHANCE TO SEE WIDESPREAD FOG...POSSIBLY DENSE AT TIMES...WILL BE ALONG THE WI BORDER FROM IRON RIVER TO MENOMINEE NORTH TO A LINE FROM MICHIGAMME TO ESCANABA. HAVE ISSUED A SPECIAL WX STATEMENT HIGHLIGHTING THE CENTRAL CWA. WITH A QUICKLY LOWERING SUN ANGLE...FOG AND STRATUS WERE SLOW TO ERODE THIS MORNING. A SIMILAR TREND CAN BE EXPECTED WEDNESDAY...SO ANY FOG WILL LIKELY SLOWLY LIFT TO A STRATOCUMULUS LAYER BEFORE GRADUALLY DISSIPATING BY THE AFTERNOON. WITH A STOUT INVERSION AROUND 3KFT AND CONTINUING MOISTURE FLOWING OFF LAKE MI AND GREEN BAY...EXCEPT A FLAT STRATOCU DECK TO REMAIN ACROSS THE SOUTH-CENTRAL AND EASTERN CWA FOR MUCH OF THE DAY. LOWERED TEMPS A TOUCH GIVEN COOLER TRENDS TODAY WITH SIMILAR CONDITIONS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 424 PM EDT TUE SEP 24 2013 HIGH PRESSURE WILL DOMINATE MUCH OF THIS TIME PERIOD. AT 00Z THURSDAY THE UPPER GREAT LAKES WILL BE DOMINATED BY HIGH PRESSURE AT THE SFC AND ALOFT...WITH LOW PRESSURE OVER THE INTERMOUNTAIN WEST UP THROUGH W CANADA. THE RESULT FOR OUR REGION WILL BE CONTINUED DRY WEATHER AND LIGHT WINDS. WINDS AND TEMPS WILL BE ON THE INCREASE THURSDAY AFTERNOON AS THE PRESSURE GRADIENT INCREASES BETWEEN THE HIGH INCREASING OVER THE E PORTION OF THE CWA...AND THE LINGERING TROUGH TO THE W. WHILE THERE ARE STILL SOME SIGNIFICANT DIFFERENCES IN THE MID RANGE MODELS...THEY HAVE BECOME A LOT MORE PROGRESSIVE THAN THE CLOSED LOW DEPICTED OFF THE ECMWF OF 24HRS AGO. NOW THE 12Z MODELS HAVE THE 500MB TROUGH SET UP ACROSS MN AT 00Z SUNDAY...WITH THE COLD FRONT EITHER ACROSS THE CENTRAL PORTIONS OF THE CWA AT OR OVER THE FAR W. THE OVERALL TREND IS THE SAME...WITH THE ECMWF BEING THE SLOWER SOLUTION. EXPECT THE FRONT TO BE KICKED E BY 15Z SUNDAY. KEPT THE AREA TS FREE...WITH ONLY A THIN-MODERATE LINE OF SHOWERS EXPECTED. THE ECMWF DOES HAVE MU CAPE VALUES NEARING 100J/KG ALONG THE WI BORDER SATURDAY...WITH IS PRETTY MINOR. WILL CONTINUE TO FINE-TUNE THIS PORTION OF THE FCST AS THE TIME NEARS. HIGH PRESSURE SHOULD QUICKLY FILL BACK IN BEHIND THE COLD FRONT SUNDAY AFTERNOON. WENT AHEAD AND DIMINISHED THE POTENTIAL FOR LINGERING SHOWERS A BIT MORE SUNDAY AFTERNOON-SUNDAY NIGHT...AS WELL AS MONDAY AND MONDAY NIGHT WITH NO MORE CLOSED LOW ANTICIPATED. THERE IS STILL QUITE A DIFFERENCE IN THE 500MB PATTERN FOR THE START OF NEXT WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 712 PM EDT TUE SEP 24 2013 VFR CONDITIONS THIS EVENING AT ALL SITES AS HIGH PRESSURE REMAINS IN CONTROL. MAIN CONCERN WILL BE FOG DEVELOPMENT AT SAW AND CMX LATE TONIGHT. EXPECT IWD TO REMAIN VFR WITH LIGHT DOWNSLOPING S WINDS. PERSISTENT CONDITIONS AND CALM WINDS UNDER HIGH PRESSURE WILL LEAD TO RADIATIONAL FOG DEVELOPMENT ACROSS CENTRAL UPPER MI OVERNIGHT. KEPT SAW FORECAST REACHING LIFR-VLIFR THRESHOLD LATE TONIGHT INTO WEDNESDAY MORNING. STILL SOME POTENTIAL THAT VLIFR/LANDING MIN CONDITIONS COULD BE OBSERVED AS EARLY AS 08Z AND AS LATE AS 13Z. AS FOR CMX...EXPECT SOME GROUND FOG WITH MAINLY MVFR CONDITIONS AS WAS SEEN ON TUESDAY MORNING. MAY SEE BRIEF IFR VSBY AS WELL. EXPECT FOG/LOW STRATUS TO DISSIPATE SLOWLY ON WEDNESDAY AT SAW WITH MIXING NOT KICKING IN UNTIL AFTN. RETAINED SLOWER DISSIPATING TREND...WITH SAW POSSIBLY NOT BREAKING OUT UNTIL MID AFTN. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 336 PM EDT TUE SEP 24 2013 HIGH PRESSURE WILL KEEP WINDS UNDER 15 KNOTS FROM THE SOUTH TO SOUTHEAST THROUGH THURSDAY BEFORE AN APPROACHING TROUGH BEGINS TO VEER WINDS FROM THE SOUTH BY FRIDAY. SOUTH WINDS WILL GRADUALLY INCREASE TO UP TO 20 KNOTS THROUGH SATURDAY AS LOW PRESSURE TRACKING ACROSS NORTHERN MANITOBA PASSES A COLD FRONT ACROSS LAKE SUPERIOR SATURDAY EVENING. WESTERLY WINDS UNDER 15 KNOTS WILL ENSUE THROUGH EARLY NEXT WEEK AS HIGH PRESSURE BUILDS BACK INTO THE REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...KLUBER LONG TERM...KF AVIATION...JLA MARINE...KLUBER