122 FXUS63 KMQT 280950 AFDMQT AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 450 AM EST MON JAN 28 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 444 PM EST SUN JAN 27 2013 STRONG SHORTWAVE IS CURRENTLY MOVING NORTHEAST THROUGH EASTERN IOWA AND SOUTHWEST WI THIS AFTERNOON. BROAD AREA OF PRECIPITATION HAS BEEN OCCURRING ALONG AND AHEAD OF THIS SHORTWAVE...WITH A WIDE RANGE OF PRECIPITATION TYPES REPORTED. THIS SHORTWAVE WILL CONTINUE TO THE NORTHEAST LATE THIS AFTERNOON AND TONIGHT AND BE THE MAIN FEATURE OF NOTE FOR THE SHORT TERM. INITIAL AREA OF PRECIPITATION THIS MORNING AND EARLY AFTERNOON FOCUSED ON THE H650-500 FGEN AND EXPECT THAT TO CONTINUE NORTHEAST AND BE THE MAIN AREA OF FORCING FOR THE INITIAL PRECIP. THE BEST FGEN AND MID LEVEL FORCING LOOKS TO BE ACROSS SOUTHEAST UPPER MICHIGAN FOR THIS FIRST WAVE. THEN AS THAT SLIDES NORTHEAST AND THE H850-700 WAA/FGEN PUSH THROUGH THE CENTRAL AND EASTERN CWA...SHOULD SEE A SECONDARY SURGE OF PRECIP. LOOKING AT BUFKIT TEMPERATURE PROFILES AND WETBULB TEMPS...LOOKS LIKE PRECIP SHOULD FALL AS ALL SNOW...BUT THERE COULD BE A VERY BRIEF PERIOD OF MIXED PRECIPITATION AT THE START. WITH THE FIRST PUSH OF SNOW...THINK THERE COULD BE A BRIEF PERIOD OF HIGHER SNOW RATIOS...TOWARDS 13-1...DUE TO THE FORCING FOCUSED IN THE DGZ. BUT WITH THE INCREASING FORCING/SATURATION BELOW THE DGZ HEADING INTO THE OVERNIGHT HOURS...LOWER 10-12KFT OF THE CLOUD AROUND -5 TO -2C...THINKING THAT SNOW RATIOS WILL QUICKLY FALL TOWARDS A 9/10 TO 1 RANGE. THIS PRODUCES AN OVERALL SNOWRATIO AVERAGE FOR THE EVENING AROUND 10-11 TO 1. QPF HAS BEEN DIFFICULT TO PIN DOWN...BUT WITH PWATS AROUND 250-300 PERCENT OF NORMAL...THERE IS PLENTY OF MOISTURE TO WORK WITH. HAVE OPTED TO FOLLOW THE LATEST TRENDS IN THE MODELS WITH AN INCREASE IN QPF TO THE NORTHWEST AND HAVE GENERALLY 0.25-0.45 INCH OF QPF OVER MUCH OF THE CWA. TRIED TO MATCH THE HIGHEST QPF ON LATEST TRENDS AND 09Z SREF PROBABILITIES. IT/S PROBABILITIES ARE MAINLY IN THE SIMILAR RANGE AS THE GOING FORECAST WITH ONLY A SMALL SWATH OF 10 PERCENT CHANCE OF 0.50 INCH QPF IN 12HRS ACROSS THE CENTRAL CWA. BIG QUESTION IS HOW FAR WEST THINGS GO. LATEST MODEL TRENDS ARE PUSHING IT FARTHER TO THE WEST AND TIED TO THE H925-700 WARM AIR ADVECTION AND ASSOCIATED FGEN THAT IS CENTERED WITH THE PRECIPITATION CURRENTLY NEAR AND SW OF MINNEAPOLIS. THIS SECONDARY SURGE OF PRECIPITATION WOULD OCCUR ON TOP OF THE INITIAL MID LEVEL FORCED PRECIP MOVING THROUGH DURING THE EVENING. WITH THE WAY THE WAA/FGEN IS LIKELY TO BE FOCUSED...AND THE THE ONGOING CONVECTION IN THAT AREA THIS MORNING IN NE NEBRASKA AND SOUTHEAST SD...WOULD NOT BE SURPRISED IF THERE WAS A SMALL SWATH OF HIGHER PRECIP AND POTENTIALLY WARNING SNOW SOMEWHERE BETWEEN A LINE FROM IRON RIVER TO NEGAUNEE AND CARNEY TO CHATHAM. HAVE ADJUSTED SNOW AMOUNTS UP TO JUST UNDER 6 INCHES IN THAT AREA AND WILL HIGHLIGHT SOME LOCALLY HIGHER AMOUNTS IN THE WSW. OTHERWISE...LOOKS TO BE A SOLID ADVISORY SNOW ACROSS MUCH OF THE AREA AND WILL CONTINUE THE WESTWARD PUSH STARTED THIS AFTERNOON TO THE ADVISORIES AND ADD THE REST OF WESTERN UPPER MICHIGAN. KEWEENAW COUNTY IS ON THE EDGE...BUT FELT CONFIDENT ENOUGH ON 2-3 INCHES TO INCLUDE IT. PRECIPITATION SHOULD BE DIMINISHING FROM SW TO NE THROUGH THE FIRST PART OF THE MORNING AND MAY SEE A BRIEF PERIOD OF FREEZING DRIZZLE AS THE DEEPER MOISTURE DEPARTS AND THE REMAINING CLOUD LAYER IS IN THE -3C TO 0C TEMP RANGE. THE LIGHT SOUTHEAST AND THEN SOUTH UPSLOPE FLOW WILL AID THE FAVORED LOCATIONS THROUGH THE FIRST PART OF THE AFTERNOON...BUT THEN THE CLOUD LAYER DEPTH REALLY DECREASES AND HAVE FOLLOWED SUIT WITH THE FREEZING DRIZZLE. WITH ALL OF THE WARM AIR PUSHED NORTH WITH THIS SYSTEM...EXPECT TEMPERATURES TO BE WELL ABOVE NORMAL EVEN WITH THE MOSTLY CLOUDY SKIES. HIGHS LOOK TO BE IN THE LOW TO MID 30S...WITH THE WARMEST VALUES NEAR THE WI BORDER. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 449 AM EST MON JAN 28 2013 WE WILL BEGIN TUESDAY WITH SW FLOW ALOFT...WITH THE MAIN 500MB LOW OVER MANITOBA WITH A TROUGH EXTENDING THROUGH THE 4 CORNERS REGION. THE SFC LOW SHOULD BE OVER NE IA OR SW WI. GIVEN THE SURGE OF WARM AIR AND SSW 850MB WINDS OF 40-45KTS CENTRAL AND E...850MB TEMPS SHOULD START OFF IN THE 2 TO 7C RANGE /WARMEST S CENTRAL/. THE DEEPENING SFC LOW SHOULD PUSH ACROSS CENTRAL UPPER MI BY 18Z TUESDAY...BEFORE EXITING OVER NE LAKE SUPERIOR AND JAMES BAY BY 06Z WEDNESDAY. THE SOUTHERN ENHANCEMENT WILL PRODUCE A TRAILING LOW ALONG THE COLD FRONT ACROSS MO/IL AT 00Z WED WHICH WILL CONTINUE TO PUSH NE THROUGH THE EVENING HOURS TUESDAY. WHILE THE MAJORITY OF THE FCST SOLUTION ARE CONSISTENT WITH THIS SOLUTION THROUGH 00Z WEDNESDAY...AND THEN BRING THE SECONDARY LOW ACROSS LOWER MI TUESDAY NIGHT...THE 00Z/28 GFS MOVED APPROXIMATELY 180-200MI TO THE NW OF ITS 18Z RUN. THIS BRINGS THE LOW ACROSS THE MACKINAC BRIDGE AT 12Z WEDNESDAY INSTEAD OF CENTRAL LOWER MI. IF THE 00Z/28 GFS PANS OUT...IT WOULD HAVE SIGNIFICANT IMPLICATIONS FOR UPPER MI...PAINTING 0.5-0.75IN LIQUID. THIS WOULD LIKELY RESULT IN WARNING AMOUNTS OF SNOW...WHERE AS THE MAJORITY OF THE MODELS /NAM/CANADIAN FOR THE MOST PART/AND 12Z AND 00Z ECMWF RUNS/ HAVE 0-0.02IN OF LIQUID. WILL HOLD OFF ON MAKING ANY WIDESPREAD CHANGES. THE 00Z/28 UKMET IS NEARLY MIDDLE OF THE ROAD WITH THE SYSTEM...PAINTING AROUND 0.25IN LIQUID OVER CENTRAL AND E UPPER THROUGH THE DAY WEDNESDAY. AS THE DEEPENING SYSTEM EXITS INCREASED NW WINDS WILL BE POSSIBLE...WITH GUSTS IN THE 15 TO 25KT RANGE...ASSISTING IN REDUCING VIS WITH BLOWING SNOW. THE STRONGEST WINDS ARE FIGURED WEDNESDAY AFTERNOON AND EVENING. COLD AIR PUSHING IN WILL RESULT IN STEADY TO SLOWLY FALLING TEMPS W TO E WEDNESDAY INTO WEDNESDAY NIGHT. THE 850MB TEMPS AROUND 0C AT 00Z WEDNESDAY WILL QUICKLY FALL TO AN AVERAGE -17C BY 00Z THURSDAY...AND CONTINUE TO VARY BETWEEN -17 AND -23C THROUGH THE REMAINDER OF THE PERIOD. THE APEX OF THE 500MB TROUGH WILL BE OVERHEAD WEDNESDAY AFTERNOON...WITH REINFORCING SYSTEMS PUSHING IN FROM THE NW KEEPING THE BROAD THROUGH OVERHEAD THROUGH AT LEAST SUNDAY. FCST MODELS...AS EXPECTED...BECOME MORE UNCERTAIN AS WE MOVE INTO LATE SUNDAY. AS WE LOOK AT YET ANOTHER PROLONGED PERIOD OF COLD NW-W WIND ACROSS LAKE SUPERIOR AND UPPER MI...WE WILL LIKELY NEED EXTENDED LAKE EFFECT SNOW ADVISORIES. WHILE THE DISCUSSION CAME UP ABOUT POSSIBLY ISSUING A WATCH...WE DECIDED AGAINST IT DUE TO THE PROLONGED EVENT AND UNCERTAINTY OF RECEIVING 12IN OR MORE OF SNOW IN 24 HRS /OR 8IN IN 12HRS/. WILL CONTINUE TO MENTION A PROLONGED PERIOD OF NW WINDS FROM WEDNESDAY THROUGH SATURDAY...WITH BLOWING SNOW POSSIBLE AS WELL...WITH MODERATE SNOW ACCUMULATIONS AND REDUCED VISIBILITIES. TAKING AT LOOK AT THE LATEST GUIDANCE AND OUR ONGOING FORECAST FOR THURSDAY THROUGH SUNDAY...FEW CHANGES WERE NEEDED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1242 AM EST MON JAN 28 2013 CONDITIONS AT ALL THREE SITES WILL STAY AT IFR TO LIFR OVERNIGHT. THE SNOW WILL BEGIN TO LET UP TOWARDS DAYBREAK FROM SOUTHWEST TO NORTHEAST AND IMPROVE VISIBILITIES. BUT WARM/MOIST AIR WILL CONTINUE TO KEEP LOW CLOUDS THROUGH THE AFTERNOON. THERE IS ALSO THE POTENTIAL FOR SOME FREEZING DRIZZLE FOR A FEW HOURS THIS MORNING AS THE SNOW ENDS. IWD WILL SEE MVFR CONDITIONS THIS AFTERNOON WITH SOME DRIER AIR COMING IN. THE LOW IFR/LIFR CLOUDS WILL REMAIN AT CMX INTO THIS EVENING AND WILL REMAIN AT SAW THROUGH THE FORECAST PERIOD. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 444 PM EST SUN JAN 27 2013 WINDS WILL MOSTLY BE UNDER 15KT OVER WESTERN LAKE SUPERIOR THRU MON. OVER EASTERN LAKE SUPERIOR...SOUTHERLY WINDS IN THE 15-25KT RANGE WILL FALL BACK UNDER 15KT MON AS PRES GRADIENT WEAKENS. S TO SE WINDS WILL THEN INCREASE BACK TO 15-25KT OVER ERN LAKE SUPERIOR MON NIGHT/TUE AHEAD OF AN APPROACHING COLD FRONT. WINDS WILL REMAIN LIGHTER OVER THE W. AFTER THE COLD FRONT PASSES...ARCTIC AIR WILL FLOW BACK INTO THE UPPER LAKES ON NW WINDS MOSTLY IN THE 20-30KT RANGE WED THRU FRI. WINDS/WAVES COMBINED WITH ARCTIC AIR SETTLING OVER THE AREA WILL RESULT IN FREEZING SPRAY...POSSIBLY HEAVY AT TIMES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ006- 007-085. WINTER WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR MIZ001-003>005-010-011. WINTER WEATHER ADVISORY UNTIL 9 AM EST /8 AM CST/ THIS MORNING FOR MIZ002-009-084. WINTER WEATHER ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR MIZ012>014. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KF AVIATION...07 MARINE...ROLFSON