236 FXUS63 KMQT 190540 AFDMQT AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 140 AM EDT TUE MAR 19 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 429 PM EDT MON MAR 18 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW NEG-TILT TROUGH/VIGOROUS SHORTWAVE OVER ERN IA/SW WI POISED TO LIFT ENE INTO THE GREAT LAKES AREA TONIGHT. AREA OF SNOW ASSOC WITH THIS FEATURE STRETCHES FROM WRN LAKE SUPERIOR/SW UPR MI INTO WI AND NRN LAKE MI. FRONTAL BOUNDARY OVER THE OHIO/TENNESSEE VALLEYS HAS EFFECTIVELY ROBBED THE BETTER SURGE OF GULF MOISTURE N TO THE UPPER LAKES AHEAD OF WAVE. PER 12Z RAOBS...PRECIPITABLE WATER VALUES UPWARDS OF 1 INCH ARE SOUTH OF THE BOUNDARY WHILE VALUES ARE ONE-QUARTER TO ONE-HALF INCH OVER THE NRN PLAINS...JUST A LITTLE ABOVE NORMAL FOR THIS TIME OF YEAR. THE ROBBING OF MOISTURE BY THIS SRN WAVE/FRONT WILL WORK TO KEEP SNOW ACCUMULATIONS IN CHECK DESPITE VIGOROUS DYNAMICS ASSOCIATED WITH INCREASINGLY NEG-TILT UPR MS VALLEY SHORTWAVE. MODEL CONSENSUS PCPN AMOUNTS INTO THIS EVENING ARE ROUGHLY 0.2 TO 0.25 INCHES. WITH SNOW RATIOS LIKELY AROUND 15 TO 1...ADVY FOR GENERAL SNOWFALL OF 3 TO 4 INCHES STILL LOOKS ON TRACK AS THE SNOW MAY FALL AT HEAVY AT TIMES FOR A WHILE INTO THE EVENING HRS. SYNOPTIC SNOW WILL DIMINISH TO PATCHY -SN W TO E TONIGHT AS AREA OF SNOW TIED TO STRONG FORCING AHEAD OF SHORTWAVE DEPARTS. ATTENTION LATE TONIGHT THEN TURNS TO THE WRN COUNTIES WHERE STRONG NW WINDS WILL DEVELOP IN THE WAKE OF SFC LOW MOVING ACROSS ERN LAKE SUPERIOR. THE STRONG NW WINDS WILL ARRIVE OVER GOGEBIC/ONTONAGON COUNTIES BEFORE REACHING THE KEWEENAW TUE MORNING. DEEP MOISTURE/CONVERGENT CYCLONIC WNW FLOW...THE ADVECTION OF INCREASINGLY COLDER 8H TEMPS ACROSS WRN LAKE SUPERIOR AND A DEEP DGZ SUGGEST VERY HVY LAKE ENHANCED SNOW WILL LIKELY DEVELOP FROM KIWD N THRU THE KEWEENAW BY DAYBREAK. COULD EASILY SEE SNOWFALL RATES OF 1-3IN/HR INTO TUESDAY ACROSS THE HIGHER TERRAIN OF THE W. BLSN WILL ALSO BECOME AN INCREASING HAZARD AS NW WINDS WILL GUST OVER 30MPH TO AS HIGH AS 40MPH...ESPECIALLY IN OPEN AREAS NEAR LAKE SUPERIOR. WHITE-OUTS WILL BE A GOOD POSSIBILITY DUE TO COMBINATION OF HVY SNOW/BLSN INTO TUESDAY. ERN COUNTIES WILL NOT GET INTO THE LAKE ENHANCED SNOW UNTIL WINDS SHIFT FROM WEST TO NORTHWEST BEHIND COLD FROPA. AS 8H TEMPS SLOWLY FALL TO AROUND -12 TO -13C OVER ERN LAKE SUPERIOR BY 00Z WED...EXPECT LAKE ENHANCED SNOW TO GET GOING OVER ERN ALGER...NRN SCHOOLCRAFT AND LUCE COUNTIES IN CYCLONIC WNW FLOW. ALTHOUGH BEST MODEL OMEGA INITIALLY MAY STAY BLO DGZ RESULTING IN LOWER SNOW WATER RATIOS...BELIEVE SNOW ACCUMS WILL INCREASE LATER IN THE DAY ON TUE AND ESPECIALLY LATE TUE NIGHT AND WED AS COLDER 8H TEMPS CONTINUES TO SEEP ACROSS ERN LAKE SUPERIOR AND LOW-LVL CONVERGENCE INCREASES WITH FLOW VEERING NW. NW WINDS INCREASING TO 25-30 MPH...ESPECIALLY ALONG THE LAKE SUPERIOR SHORE WILL ALSO ADD TO BLOWING SNOW AND LOWER VSBYS TUE AFTERNOON INTO WEDNESDAY. AS A RESULT OF CONDITIONS BECOMING INCREASINGLY MORE FAVORABLE FOR ENHANCED SNOW AND BLOWING SNOW TUE AFTERNOON THROUGH WED NIGHT...HAVE DECIDED TO UPGRADE WINTER STORM WATCH TO WINTER STORM WARNING FOR ALGER...LUCE AND NRN SCHOOLCRAFT COUNTIES FOR LATE TUE MORNING THROUGH WED NIGHT. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 429 PM EDT MON MAR 18 2013 ACTIVE LAKE EFFECT PERIOD FOR NORTHWESTERLY SNOW BELTS WILL CONTINUE TUESDAY NIGHT INTO EARLY THURSDAY. AS UPPER LOW CLOSES OFF JUST EAST OF THE AREA AND CYCLONIC FLOW COMBINES WITH H85 TEMPS IN THE -16 TO -18 RANGE MODERATE TO HEAVY LAKE EFFECT SNOWS WILL CONTINUE. WINDS WILL CONTINUE TO GUST OVER 35 MPH ESPECIALLY NEAR THE LAKESHORE THROUGH THE DAY WEDNESDAY INTO WEDNESDAY NIGHT. WILL MAINTAIN THE LONG DURATION WINTER STORM WARNING ACROSS THE WEST AND KEWEENAW THROUGH THE DAY WEDNESDAY AND THE EAST INTO THURSDAY MORNING. LAKE EFFECT SNOW TOTALS IN THE 12 TO 18 INCH RANGE SEEM LIKELY THROUGH THE TUESDAY TO THURSDAY PERIOD. LOW LEVEL WINDS BEGIN TO BECOME MORE NORTHERLY ON THURSDAY AS LAKE EFFECT CONDITIONS BEGIN TO BECOME LESS FAVORABLE. AS MILDER AIR WRAPS AROUND THE SLOWLY RETROGRADING UPPER LOW EXPECT 85H TEMPS TO WARM INTO THE -8 TO -10 RANGE AS INVERSION LOWERS. THIS SHOULD EFFECTIVELY END THE LAKE EFFECT BY LATE THURSDAY INTO EARLY FRIDAY. OVERALL TREND INTO THE UPCOMING WEEKEND SHOULD FAVOR GENERALLY TRANQUIL WEATHER WITH TEMPERATURES WITHIN A FEW DEGREES OF NORMAL. MODELS OFFER SOME MINOR VARIATIONS WITH UPPER LOW DEPARTING THE AREA AND UPPER PATTERN TRANSITIONING TO A MORE ZONAL FLOW WITH THE MAIN STORM TRACK SOUTH OF THE AREA...FOR NOW WILL MAINTAIN A CONSENSUS BLEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 138 AM EDT TUE MAR 19 2013 AS THE LOW PRES TROUGH LIFTS TO THE NORTHEAST OF UPPER MI...SNOW SHOULD DIMINISH FOR A WHILE OVERNIGHT AND MAY ALLOW CONDITIONS TO IMPROVE TO MVFR...ESPECIALLY AT IWD AND SAW. LATE IN THE NIGHT... STRONG WNW WINDS AND COLD AIR MOVING IN BEHIND THE LOW WILL BRING MDT/HVY LAKE ENHANCED SNOW TO IWD/CMX WITH CONDITIONS LIKELY FALLING TO LIFR. HOWEVER...THE WNW FLOW WILL FAVOR MAINLY MVFR CONDITIONS AT SAW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 429 PM EDT MON MAR 18 2013 TIGHT PRES GRADIENT AHEAD OF THE LOW OVER NW MN WILL CONTINUE SE WINDS UP TO 30KT TODAY. GALES WILL LIKELY OCCUR TOWARD MID LAKE PORTIONS OF NCNTRL AND ERN LAKE SUPERIOR...IN PARTICULAR FROM AROUND WHITEFISH PT NW TOWARD PASSAGE ISLAND. AFTER THE LOW EXITS TO THE E...NORTHWEST GALES WILL DEVELOP FROM W TO E LATE TONIGHT/TUE. THE GALES WILL THEN CONTINUE INTO WED OVER THE E HALF OF THE LAKE. WINDS WILL SLOWLY DIMINISH TO UNDER 25KT FROM W TO E WED NIGHT/THU. THE COMBINATION OF COLD AIR/STRONG WINDS/HIGH WAVES WILL LEAD TO PERIODS OF HVY FREEZING SPRAY TUE THRU WED. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER STORM WARNING UNTIL 8 PM EDT /7 PM CDT/ WEDNESDAY FOR MIZ001>004-009-084. WINTER WEATHER ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR MIZ006-007-014-085. WINTER STORM WARNING FROM 11 AM THIS MORNING TO 8 AM EDT THURSDAY FOR MIZ006-007-085. WINTER WEATHER ADVISORY UNTIL 2 AM EDT /1 AM CDT/ EARLY THIS MORNING FOR MIZ005-010>013. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT THURSDAY FOR LSZ243>245-248>251-264>267. GALE WARNING UNTIL 2 PM EDT WEDNESDAY FOR LSZ264-266-267. GALE WARNING FROM 2 PM THIS AFTERNOON TO 2 PM EDT WEDNESDAY FOR LSZ243>251-265. HEAVY FREEZING SPRAY WARNING FROM 5 AM EDT /4 AM CDT/ EARLY THIS MORNING TO 8 AM EDT /7 AM CDT/ THURSDAY FOR LSZ162-240>242- 263. GALE WARNING FROM 8 AM EDT /7 AM CDT/ THIS MORNING TO 2 PM EDT /1 PM CDT/ WEDNESDAY FOR LSZ162-240>242-263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...MZ AVIATION...JLB MARINE...VOSS