000 FXUS63 KMQT 100543 AFDMQT AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1243 AM EST FRI FEB 10 2012 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 435 PM EST THU FEB 9 2012 A 500MB LOW IS CURRENTLY OVER FAR NRN QUEBEC...WHERE IT WILL STAY THROUGH AT LEAST FRIDAY. A 500MB TROUGH IS MOVING AROUND THE W SIDE OF THIS LOW AND CURRENTLY STRETCHES FROM THE LOW CENTER TO CENTRAL MANITOBA. AT THE SFC...AN ARCTIC COLD FRONT AND ASSOCIATED TROUGH IS CURRENTLY JUST N OF THE CWA. VERY DRY AIR IN THE LOW AND MID LEVELS KEPT SKIES CLEAR...EXCEPT FOR SOME HIGH CLOUDS...ALLOWING TEMPERATURES TO CLIMB INTO THE MID 30S ACROSS MOST OF UPPER MI THIS AFTERNOON. THE COLD LOOKS TO MOVE INTO THE KEWEENAW SHORTLY AFTER 00Z FRI /ORIENTED IN A WSW TO ENE DIRECTION/...BUT FINE SCALE MODELS SUGGEST A LAKE ENHANCED BAND MAY FORM OVER OVER THE KEWEENAW A COUPLE OF HOURS AHEAD OF THE FRONT IN WLY WINDS AS 850MB TEMPS FALL TO AOB -10C. DO NOT HAVE HIGH POPS FOR THE PRE FRONTAL LES BAND SINCE AIR WILL BE SO DRY INITIALLY. BY 03Z FRI...MODELS SHOW THE COLD FRONT FROM JUST N OF THE HURON MOUNTAINS TO NEAR IRONWOOD. BY 06Z FRI...THE FRONT SHOULD BE FROM NEAR GRAND MARAIS TO IRON MOUNTAIN. THEN BY 09Z FRI...THE FRONT SHOULD BE JUST S OF THE ENTIRE CWA. EXPECT A GOOD BURST OF SNOW RIGHT ALONG THE FRONT...ESPECIALLY IN UPSLOPE AREAS NEAR LAKE SUPERIOR...WHERE SOUTH CENTRAL UPPER MI WILL LIKELY ONLY SEE MINOR SNOW ACCUMULATIONS TONIGHT. LES WILL THEN ORGANIZE BEHIND THE FRONT AS 850MB TEMPS FALL TO AROUND -18C RIGHT BEHIND THE FRONT...AND WILL BE COLDEST AROUND 12Z AS LOW AS -25C. LOW LEVEL WINDS BEHIND THE FRONT WILL BE NEARLY UNIDIRECTIONAL FROM AROUND 000 TO 010 DEGREES...PUTTING N WIND FAVORED AREAS UNDER THE GUN FOR THE BEST LES. WITH THE ARRIVAL OF THE COLDEST AIR AROUND 12Z FRI WILL ALSO COME DRIER MID LEVEL AIR AND LOWERING INVERSION HEIGHTS AS SFC RIDGING PUSHES IN FROM THE NW. BY 18Z FRI...AIR WILL BE QUITE DRY ABOVE 850MB...WITH A MORE INVERTED V TYPE SOUNDING IN THE LOW LEVELS DUE TO DAYTIME HEATING. THIS WILL LEAD TO DIMINISHING LES THROUGH THE DAY FRI...WITH ONLY SOME SCATTERED SNOW SHOWERS BY LATE IN THE DAY. AS FAR AS SNOWFALL AMOUNTS AND HAZARDS...THE HEAVIEST SNOW SHOULD FALL ALONG AND JUST BEHIND THE COLD FRONT...AND WOULD CONTINUE LONGER EXCEPT FOR THE DRY AIR MOVING IN SO QUICKLY. THE PREVIOUS FORECAST HAS SNOW TOTALS IN THE 3 TO 5 INCH RANGE OVER THE FAVORED N WIND SNOWBELTS...WHICH IS JUST SUB LES ADVISORY /5 INCHES IN 12 HOURS/. THIS LOOKS REASONABLE GIVEN HIGH SNOW TO LIQUID RATIOS IN THE 20-25 TO 1 RANGE SINCE THE BEST LIFT WILL BE IN THE DGZ DURING THE EXPECTED TIME OF HEAVIEST SNOW. HIGH RESOLUTION MODELS SUCH AS THE NCEP HIGH RES WRF-ARW/NMM THE LOCAL HIGH RES WRF WOULD SUGGEST HIGHER SNOW TOTALS...BUT THOSE APPEAR TO BE OVERDOING AMOUNTS. WILL USE THOSE MODELS FOR FROPA/PRECIP TIMING...BUT WILL UNDERPLAY THEIR QPF AMOUNTS. WINDS WILL BE GUSTY...SO THERE WILL BE SOME VISIBILITY RESTRICTIONS. WILL NOT ISSUE ANY HEADLINES AT THIS TIME DUE TO THE FACT THAT THE HEAVIEST PRECIP WILL FALL WELL BEFORE MORNING COMMUTE AND AMOUNTS SHOULD BE SUB ADVISORY AT MOST. TEMPS THU NIGHT AND FRI WILL BE VERY CHILLY...ESPECIALLY COMPARED TO OUR TEMPS AS OF LATE. LOWS TONIGHT WILL RANGE FROM NEAR 0F OVER INTERIOR W AND FAR ERN UPPER MI...TO THE LOW TEENS OVER E CENTRAL UPPER MI. HIGHS ON FRI WILL NOT BE MUCH WARMER. OVER THE W HALF OF UPPER MI...EXPECT HIGHS AROUND 10F...WITH HIGHS IN THE TEENS OVER THE E HALF OF UPPER MI. WIND CHILLS WILL ALSO BE A CONCERN...ALTHOUGH NOT LOW ENOUGH FOR ANY HEADLINES. EXPECT WIND CHILL VALUES AS LOW AS THE NEGATIVE TEENS LATE TONIGHT THROUGH FRIDAY MORNING...THEN AGAIN FRIDAY EVENING. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 435 PM EST THU FEB 9 2012 THE AO WHICH HAS BEEN POSITIVE NEARLY CONTINUALLY FROM EARLY NOV HAS BECOME NEGATIVE IN THE LAST FEW WEEKS. HOWEVER...THE NAO HAS REMAINED POSITIVE...SO THE WARM WINTER PATTERN HAS CONTINUED FOR UPPER MI DESPITE THE AO TURNING NEGATIVE. SINCE NOV 1...THE AVG TEMP HERE AT THE NWS OFFICE HAS BEEN 24.9F...MAKING THIS THE 3RD WARMEST NOV 1-FEB 8 PERIOD ON RECORD. THE WARMEST NOV 1-FEB 8 PERIOD OCCURRED IN 2001-2002 WITH AN AVG TEMP OF 28.1F. OVER THE NEXT WEEK OR SO...IT LOOKS LIKE THE AO WILL REMAIN NEGATIVE...BUT LESS SO... WHILE THE NAO TRENDS TOWARD NEUTRAL/NEGATIVE. THIS WILL PROBABLY RESULT IN ABOVE NORMAL TEMPS ON THE WHOLE THRU NEXT WEEK. HOWEVER... THERE WILL BE A PERIOD OF COLDER AIR/BLO NORMAL TEMPS OVER THE NEXT FEW DAYS AS DEEP POLAR VORTEX CENTERED JUST NE OF HUDSON BAY SWINGS A PORTION OF ITS ASSOCIATED ARCTIC AIRMASS INTO THE GREAT LAKES REGION IN RESPONSE TO A RIDGE THAT HAS BUILT N THRU THE NW TERRITORIES. AFTER THE PUSH OF ARCTIC AIR OVER THE NEXT FEW DAYS... THE NRN STREAM WILL RETREAT WITH PATTERN TAKING ON A DISTINCT SPLIT FLOW NEXT WEEK. WHETHER OR NOT THIS SPLIT FLOW LEADS TO ANY SRN STREAM SYSTEMS REACHING THE UPPER GREAT LAKES REMAINS TO BE SEEN. RIGHT NOW...IT APPEARS THAT THE OVERALL DRY PATTERN WILL PERSIST NEXT WEEK. BEGINNING FRIDAY NIGHT...WITH 850MB TEMPS AROUND -20C...LES WILL BE ONGOING IN AREAS FAVORED BY NW WINDS. DRY AIR/LOW INVERSION BLO 4KFT AND HINTS OF INVERTED-V/WELL-MIXED BOUNDARY LAYER WILL KEEP LES LIGHT INITIALLY. HOWEVER...WITH THE DENDRITIC SNOW GROWTH TEMP ZONE (DGZ) IN THE CONVECTIVE LAYER...MIGHT STILL BE ABLE TO FLUFF UP A FEW INCHES OF SNOW LOCALLY...HIGHEST OVER THE NE FCST AREA WHERE LONGER OVERWATER FETCH CAN WORK TO OFFSET DRY AIR. WINDS OVER FAR SW UPPER MI MAY BACK SUFFICIENTLY TO CUT OVERWATER TRAJECTORIES ENOUGH TO ALLOW FOR SOME CLEARING. TEMPS THERE SHOULD FALL INTO THE SINGLE DIGITS BLO ZERO. ELSEWHERE...TEMPS SHOULDN'T FALL BLO THE SINGLE DIGITS/LWR TEENS AS SFC-925MB WINDS MAINTAIN A FLOW OFF OF LAKE SUPERIOR. LOOKS LIKE LES WILL RAMP UP SAT/SAT EVENING AS A SHORTWAVE DROPS S AROUND POLAR VORTEX CENTERED NE OF JAMES BAY. WITH 850MB TEMPS MODERATING SLIGHTLY...DGZ RISES A BIT AND BECOMES MORE IDEALLY POSITIONED IN THE CONVECTIVE LAYER/UPWARD MOTION REGION. RISING INVERSION/DEEPER MOISTURE PROFILE AND CONVERGENT NORTHWESTERLY FLOW ALL POINT TO POTENTIAL HEADLINE EVENT...MORE LIKELY ADVY GIVEN THE SHORT WINDOW WHERE ALL PARAMETERS LINE UP BEST (UPWARD MOTION IN DGZ/DEEP MOISTURE/HIGHER INVERSION HEIGHTS). LONGER FETCH AND LONGER DURATION OF MORE FAVORABLE LES PARAMETERS SUGGEST BEST SNOW ACCUMULATIONS WILL BE OVER THE NE FCST AREA. OVER WRN LAKE SUPERIOR...FLOW IS MORE WESTERLY. AS IS OFTEN THE CASE WITH WESTERLY WINDS IN THAT AREA...ENHANCED CONVERGENCE COULD SET UP BTWN THE PORCUPINE MTNS AND HOUGHTON DUE TO A SLIGHTLY MORE SOUTHERLY WIND COMPONENT TOWARD THE APOSTLE ISLANDS AND A MORE NORTHERLY COMPONENT TOWARD ISLE ROYALE. SO...BEST SNOW ACCUMULATIONS IN WRN UPPER MI WILL PROBABLY OCCUR IN THAT AREA. LES WILL WIND DOWN ALONG WITH DECREASING CLOUDS W TO E LATER SAT NIGHT INTO SUN AS WAA BEGINS. BY SUN EVENING...AIR MASS SHOULD BE WARM ENOUGH TO BRING AN END TO ANY LINGERING LES OVER THE NE FCST AREA. MON THRU THU...AS ALLUDED TO ABOVE...NRN STREAM RETREATS WITH SPLIT FLOW BEING THE RULE NEXT WEEK. STILL LOOKS LIKE A SRN BRANCH WAVE MOVING INTO THE MID MISSISSIPPI VALLEY MON MAY BRING THE NRN END OF ASSOCIATED -SN SHIELD INTO PORTIONS OF SRN UPPER MI. NOTHING MORE THAN LOW CHC/SLIGHT CHC POPS ARE WARRANTED. BENIGN/DRY WEATHER THEN FOLLOWS TUE/WED. EVEN LES WON'T BE A CONCERN WITH CONSENSUS 850MB TEMPS WARMER THAN -8C. HEADING INTO THU...GFS/ECMWF INDICATE NRN STREAM ENERGY PASSING BY TO THE N WHILE ANOTHER SRN STREAM SYSTEM MOVES TO THE MID MISSISSIPPI VALLEY. TRACK OF NRN WAVE N OF UPPER MI SUGGESTS MINIMAL PCPN THREAT HERE....AND SIMILAR TO THE PREVIOUS SRN BRANCH WAVE...PCPN WITH THE SRN SYSTEM WILL LARGELY PASS BY TO THE S. SO...OPTED FOR A DRY FCST FOR THU. RETREATING NRN STREAM AND SPLIT FLOW SUGGESTS TEMPS WILL RETURN TO ABOVE NORMAL VALUES NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1242 AM EST FRI FEB 10 2012 LAKE EFFECT SNOW AND BLOWING SNOW WILL CONTINUE OVERNIGHT WITH BLUSTERY NRLY FLOW AND MUCH COLDER AIR MOVING INTO THE REGION. SO...MAINLY IFR VSBY AND LOWER END MVFR VSBY SHOULD PREVAIL INTO FRI MORNING. WITH THE VERY DRY ARCTIC AIRMASS MOVING IN...EXPECT SLOW IMPROVEMENT TO MVFR CONDITIONS BY AFTERNOON. WITH TRAJECTORIES REMAINING OFF OF LAKE SUPERIOR...MVFR CIGS SHOULD PERSIST INTO FRI EVENING EVEN AS THE LAKE EFFECT SNOW DIMINISHES. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 435 PM EST THU FEB 9 2012 AN ARCTIC COLD FRONT WILL MOVE ACROSS LAKE SUPERIOR THIS EVENING...USHERING IN MUCH COLDER AIR. EXPECT OCCASIONAL NORTHERLY GALE GUSTS TO 35KTS AND HEAVY FREEZING SPRAY...ESPECIALLY ACROSS THE CENTRAL AND EASTERN LAKE. A LULL IN THE WINDS AND HEAVY FREEZING SPRAY CAN BE EXPECTED FRIDAY AFTERNOON AS A LOW LEVEL RIDGE BUILDS IN FROM THE NORTH. THEN FROM FRIDAY NIGHT THROUGH SATURDAY NIGHT...AN INCREASING PRESSURE GRADIENT FROM A RIDGE IN THE NORTHERN PLAINS BUILDING IN ON THE BACK SIDE OF THE DEPARTING EASTERN TROUGH WILL BRING NORTHWESTERLY GALES TO 35KTS AND HEAVY FREEZING SPRAY TO PORTIONS OF LAKE SUPERIOR. CONDITIONS QUIET DOWN FOR THE REMAINDER OF THE PERIOD STARTING SUNDAY AS THE RIDGE MOVES OVER THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ SATURDAY FOR LSZ162-240>251-263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...TITUS LONG TERM...ROLFSON AVIATION...JLB MARINE...TITUS