376 FXUS63 KMQT 042041 AFDMQT AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 341 PM EST FRI JAN 4 2013 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 339 PM EST FRI JAN 4 2013 GUSTY W WINDS CONTINUED THROUGHOUT THE DAY TODAY AS TIGHT PRESSURE GRADIENTS ORIENTED THEMSELVES ACROSS THE UPPER GREAT LAKE REGION IN RESPONSE TO A 500MB TROUGH MOVING EASTWARD ACROSS QUEBEC...ANOTHER TROUGH MOVING ACROSS THE OHIO VALLEY...AND STRONG RIDGING MOVING INTO THE REGION FROM CANADA. AS ALL SYSTEMS CONTINUE TO PUSH EASTWARD OVERNIGHT...EXPECT WINDS TO CONTINUE TO SLOWLY DIMINISH. THIS WILL ALSO BE AIDED BY A SURFACE COLD FRONT...CONNECTING FROM THE EXITING SURFACE LOW PRESSURE TO THE NORTHEAST TO AN APPROACHING SURFACE LOW OVER CURRENTLY ENTERING IN TO THE DAKOTAS. AS LOW PRESSURE ACROSS THE DAKOTAS MOVES EASTWARD TOWARDS UPPER MI...COLD FRONT WILL DROP SOUTHWARD ACROSS LAKE SUPERIOR...CAUSING WINDS TO VEER FROM NW TO NE...AND THEN EVENTUALLY SE BY DAYBREAK TOMORROW. BEHIND THIS COLD FRONT MODEL RUNS AND FORECASTED SOUNDINGS SHOW A DRY COLUMN THAT SHOULD MAKE BRIEFLY MAKE ITS WAY INTO UPPER MI OVERNIGHT...HOWEVER VIS IMAGERY SHOWS A DECK OF CLOUDS MAKING THEIR WAY SE FROM ONTARIO ACROSS THE N LAKE. THAT BEING SAID...COULD SEE SOME SCATTERED CLOUDS MOVE INTO THE CWA NEAR LAKE SUPERIOR...WITH MORE WIDESPREAD CLOUD COVER ACROSS THE EASTERN CWA IN A MORE FAVORED REGION FOR NW WINDS. TEMPERATURES OVERNIGHT WILL MOST LIKELY BE A CHALLENGE IN RESPONSE TO THIS SOMEWHAT UNCERTAIN SET UP OF CLOUD COVER. WINDS WILL LIGHTEN AND VEER /AS MENTIONED ABOVE/ ALLOWING INTERIOR PORTIONS TO SEE VARIABLE WINDS AND POTENTIALLY DROP CONSIDERABLY AS THE COLD FRONT NEARS/PASSES OVER. RAISED TEMPS SLIGHTLY FROM PREVIOUS FORECAST...WITH INTERIOR WEST SEEING LOWS IN THE SINGLE DIGITS ABOVE 0. HOWEVER...MUCH OF THIS WILL BE BASED ON IF SCATTERED CLOUD COVER DEVELOPS ACROSS THE INTERIOR AND PREVENTS SUCH A DRAMATIC DROP. FEEL MORE CONFIDENT IN THE LAKE-ENHANCED CLOUDS...SO WILL SEE MORE MODERATE TEMPERATURES NEAR THE LAKE SUPERIOR SHORELINE AND EAST /IN THE UPPER TEENS WEST AND CENTRAL...AND TEENS AND 20S EAST/. IN THE MEANTIME...500MB TROUGH AND ASSOCIATED SURFACE LOW PRESSURE SYSTEM WILL MOVE INTO THE DAKOTAS LATE TONIGHT...AND BEGIN A TREK EASTWARD TOWARDS UPPER MI...REACHING WESTERN UPPER MI BY LATE AFTERNOON.\ AS IT APPROACHES...EXPECT CLOUDS TO CONTINUE TO INCREASE DURING THE DAY TOMORROW AS WINDS TAKE ON A MORE S COMPONENT AND PULL IN MOISTURE FROM THE GULF. HOWEVER...THE SYSTEM WILL NOT BE STRONG ENOUGH TO PULL IN ENOUGH MOISTURE OR DISPLAY ENOUGH FORCING TO SEE ANYTHING IN THE WAY OF ACCUMULATING PRECIP OVER THE CWA DURING THE DAY AND EARLY AFTERNOON. Q VECTOR CONVERGENCE IS FAIRLY WEAK AS WELL. HOWEVER...WITH LATEST MODEL SOUNDINGS SHOWING A RELATIVELY DRY COLUMN AND SHALLOW MOIST LAYER NEAR THE SURFACE BELOW FREEZING...COULD SEE SOME FREEZING DRIZZLE DEVELOP ACROSS THE AREA. SOME UNCERTAINTY STILL LIES IN HOW LONG THIS WILL PERSIST...AS WELL AS EXACT LOCATIONS FOR SET UP. BEST CHANCE FOR ACTUAL PRECIP THEN WILL BE LATE SATURDAY EVENING AND OVERNIGHT INTO SUNDAY AS WINDS TURN MORE NE AND COLD MOIST AIR GETS PULLED IN ACROSS THE LAKE...MAKING A DECENT SET UP FOR SOME LAKE EFFECT SNOW DEVELOPMENT. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 339 PM EST FRI JAN 4 2013 ON SATURDAY NIGHT...LOW PRESSURE WILL BE OVER THE UPPER GREAT LAKES ASSOCIATED WITH A WEAK UPPER DISTURBANCE MOVING THROUGH IN THE NW FLOW ALOFT. MEANWHILE...SOUTHERN STREAM ENERGY WILL BE MOVING FROM THE SRN PLAINS INTO THE EASTERN GREAT LAKES. ALTHOUGH THESE FEATURES NEVER TRULY PHASE PER SE...THE SRN STREAM FEATURE DOES ALLOW FOR MOISTURE TO BE ENTRAINED INTO THE COLD CONVEYOR BELT OF THE NRN STREAM SYSTEM AND SPREAD BACK INTO THE UPPER LAKES TO THE NW OF THE SFC LOW. HOWEVER...BEFORE THAT OCCURS EXPECT PATCHY FREEZING DRIZZLE TO DEVELOP SAT EVENING ACROSS THE EASTERN HALF WITH DRY AIR ALOFT...WEAK LOW LEVEL LIFT AND A MOISTURE CONTRIBUTION FROM LAKE MICHIGAN IN SOUTHERLY FLOW. SINCE THE SURFACE LOW WILL BE MOVING JUST SOUTH OF THE REGION...N-NE FLOW WILL PERSIST FOR MUCH OF THE NIGHT ACROSS UPPER MICHIGAN. THIS SHOULD ALLOW FOR LAKE ENHANCEMENT TO DEVELOP AS THE 850MB TEMPS COOL TO -10 TO -12C. WITH THE DEFORMATION ZONE DYNAMICS COMBINING WITH ANY LAKE ENHANCEMENT/UPSLOPE...EXPECT A PERIOD OF SNOW FOR MOST AREAS NEAR LAKE SUPERIOR WITH THE BEST CHANCES FOR SNOW ACROSS N-CENTRAL UPPER MICHIGAN. IN FACT...WOULD NOT BE SURPRISED TO SEE A QUICK INCH OR TWO FROM THIS SYSTEM NEAR LAKE SUPERIOR SAT NIGHT. MAY SEE A LITTLE LES SUN MORNING NEAR LAKE SUPERIOR...BUT THE INVERSION HEIGHTS WILL ONLY BE ABOUT 4000 FT AND THE TEMP AT THE THE TOP OF THE INVERSION WILL ONLY BE AROUND -11C. WILL KEEP SCATTERED SNOW SHOWERS NEAR LAKE SUPERIOR SUNDAY MORNING...BUT END THEM SUN AFTN AS THE HIGH BUILDS IN ALONG WITH WARM ADVECTION IN BACKING WINDS. SHOULD STAY FAIRLY QUIET WITH A SLOW WARMING TREND FOR MONDAY/TUESDAY. AN UPPER TROUGH AND ASSOCIATED SFC LOW WILL PASS WELL NORTH OF LAKE SUPERIOR MON INTO MON NIGHT. MAY SEE SOME FLURRIES OR LIGHT SNOW OVER THE LAKE...BUT WITH ALL OF THE MOISTURE WELL NORTH OF THE AREA...THE MAIN WEATHER FROM THIS SYSTEM WILL BE BREEZY SW-W WINDS. FOR THE EXTENDED PERIOD -- TUESDAY-FRIDAY -- EXPECT THE WARMING TREND TO CONTINUE WITH THE NORTHERN STREAM MOVING NORTH TO THE CANADIAN BORDER. MEANWHILE...AN UPPER LOW WILL CLOSE OFF OVER THE SOUTHWESTERN STATES. THIS UPPER LOW WILL BE THE MAIN WEATHER PRODUCER FOR MUCH OF THE MIDDLE PART OF THE COUNTRY FOR MID-LATE WEEK. THE ECMWF SEEMS TO HAVE A VERY GOOD HANDLE ON THIS SYSTEM FOR THE PAST FEW RUNS...AND HAVE OPTED TO TREND THE FORECAST TOWARD THIS SLOWER SOLUTION FOR MID-LATE WEEK. WITH THAT BEING SAID...HAVE OPTED TO CUT BACK POPS FOR TUE AND WED AS NORTHERN STREAM ENERGY/MOISTURE IS EXPECTED TO REMAIN NORTH OF THE LAKE. THE SOUTHERN STREAM SYSTEM IS FORECAST TO EJECT INTO THE PLAINS WED AND THEN INTO THE UPPER MIDWEST/GREAT LAKES ON THU/THU NIGHT. THE SLOWER SOLUTION MAKES SENSE GIVEN THAT THE LOW WILL BE COMPLETELY CUT OFF OVER THE SW STATES UNTIL MIDWEEK WHEN THE KICKER TROUGH MOVES INTO THE PACIFIC NW. NO COLD AIR TO SPEAK OF...SO DESPITE THE LOW MOVING OVER LOWER MICHIGAN...EXPECT A MIX OF RAIN AND SNOW AT BEST (AND PROBABLY ALL RAIN IF THE ECMWF THERMAL FIELDS ARE ACCURATE) ON THU. AS THE LOW PASSES EAST THU NIGHT...ENOUGH COLD AIR SHOULD BE DRAWN DOWN TO CHANGE ANY RAIN BACK TO SNOW SHOWERS...BUT EVEN THAT IS IN DOUBT WHEN LOOKING AT THE SLIGHTLY WARMER 12Z ECMWF. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1243 PM EST FRI JAN 4 2013 A STEADY BAND OF LOW-MID LEVEL MOISTURE SLIDING IN FROM W ONTARIO HAS BROUGHT IFR TO MVFR VIS AND MVFR CEILINGS TO CMX SINCE APPROX 5Z. ALTHOUGH THE HIGH CLOUDS ARE EXITING...THE LOW-MID CLOUDS HAVE BEEN DIFFICULT TO GET RID OF IN THIS LOCATION. SO FAR KSAW HAS BENEFITED FROM THE DOWNSLOPING DIRECTION OF THE WINDS AND WILL CONTINUE TO SEE CLEAR CONDITIONS AS A RESULT...AS WILL KIWD. TIGHT PRESSURE GRADIENTS ACROSS UPPER MI WILL KEEP GUSTY W WINDS THROUGH THE DAY AND INTO THE OVERNIGHT HOURS...AT WHICH POINT LOW PRESSURE WILL NEAR FROM THE W AND CAUSE WINDS TO VEER AND QUICKLY DIMINISH. CIGS ARE A LITTLE UNCERTAIN DURING THIS TIME AS GUIDANCE DOESN/T SEEM TO HAVE A GOOD HANDLE ON MOISTURE AT KCMX. BASED ON SATELLITE TRENDS...MVFR DECK SHOULD MAKE IT TO KCMX BY THIS EVENING...THOUGH SOUNDINGS INSIST ON DRY COLUMN. BASED TAFS ON OBSERVATIONS AND PREVIOUS FORECAST THINKING...THOUGH SOME TWEAKS MAY NEED TO BE MADE AS WE REACH THIS TIME FRAME AND GET A BETTER IDEA OF HOW MOISTURE FROM N WILL AFFECT CIGS AT KCMX...AND POTENTIALLY KSAW AS WELL. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 339 PM EST FRI JAN 4 2013 LOW PRESSURE OVER QUEBEC...COUPLED WITH A STRONGER HIGH PRESSURE SYSTEM QUICKLY SLIDING IN FROM CENTRAL CANADA TONIGHT...AND ANOTHER STRONG LOW TO OUR SOUTH...CONTINUES TO PRODUCE GALES FROM 35 TO 40 KNOTS OVER THE EASTERN HALF OF THE LAKE THIS AFTERNOON. AS LOW PRESSURE OVER QUEBEC CONTINUES TO MOVE EASTWARD AND HIGH PRESSURE GAINS CONTROL...GALES WILL SLOWLY DIMINISH THROUGH THE EVENING AND OVERNIGHT HOURS. LOW PRESSURE ACROSS THE DAKOTAS THIS EVENING WILL SLOWLY EDGE EASTWARD...AND CROSS THE UPPER GREAT LAKES SATURDAY EVENING INTO SUNDAY...BEFORE EXITING TO THE LOWER GREAT LAKES. THIS WILL INCREASE WIND SPEEDS TO UP TO 30 KNOTS ACROSS THE LAKE AGAIN...STARTING IN THE WESTERN LAKE SATURDAY EVENING...AND SPREADING ACROSS THE EASTERN LAKE BY EARLY MORNING SUNDAY. EXPECT A QUICK RIDGE OF HIGH PRESSURE TO PUSH ACROSS LAKE SUPERIOR SUNDAY. LOW PRESSURE STRETCHING FROM SOUTHERN CANADA TO THE CENTRAL PLAINS STATES MONDAY SHOULD SHIFT ACROSS ONTARIO MONDAY NIGHT...ALLOWING A TROUGH TO TRAVERSE LAKE SUPERIOR MONDAY NIGHT INTO TUESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ266-267. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ244-264. GALE WARNING UNTIL 6 PM EST THIS EVENING FOR LSZ265. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JMW LONG TERM...MRD AVIATION...JMW MARINE...JMW