Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 152346
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
746 PM EDT TUE APR 15 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 531 PM EDT TUE APR 15 2014

BIGGEST FORECAST CONCERNS FOR SHORT TERM FOCUS ON WINTER STORM
HEADLINES STARTING WEDNESDAY AND CONTINUING INTO THURSDAY.

WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
HUDSON BAY THROUGH THE CENTRAL GREAT LAKES INTO THE GULF COAST
STATES. INSTABILITY ASSOC WITH THIS TROUGH HAS SUPPORTED SOME
DIURNAL -SHSN ACROSS INLAND AREAS THIS AFTERNOON. THE SHORTWAVE
MOVING IN OFF THE PAC NW WILL BE THE FEATURE OF INTEREST IN THE
SHORT TERM AS IT DEVELOPS A DEEPENING STORM SYSTEM OVER THE NRN
PLAINS LATE TONIGHT AND BRINGS IT TOWARD THE WRN GREAT LAKES LATE
WED INTO WED NIGHT.

TONIGHT...ANY LEFTOVER DIURNAL SHSN OVER S CNTRL UPPER MI WILL
DIMINISH EARLY THIS EVENING AS PARTLY CLOUDY SKIES AND LIGHT WINDS
ALLOW TEMPS TO FALL INTO THE LOW SINGLE DIGITS OVER TYPICAL COLD
SPOTS FAR EAST TO 15 TO 20F RANGE FOR DOWNSLOPING AREAS ALONG LAKE
SUPERIOR FAR WEST AND AREAS CLOSE TO BAY OF GREEN BAY. TEMPS MAY
CLIMB LATE AS CLOUDS INCREASE AHEAD OF THE APPROACHING LOW PRESSURE
SYSTEM. WAA LIGHT SNOW WITH INCREASING 280K-290K ISENTROPIC LIFT IS
EXPECTED TO REMAIN MAINLY WEST OF UPPER MI BUT MAY SLIDE INTO THE
FAR WEST LATE.

WEDNESDAY...MODELS GENERALLY IN AGREEMENT SHOWING SHORTWAVE OF
INTEREST AND ASSOC DEEPENING SFC LOW OVER SE SOUTH DAKOTA AROUND 12Z
THEN DIFFER ON HOW QUICKLY THEY LIFT THIS LOW ENE TOWARD THE UPPER
GREAT LAKES. MOST OF 12Z MODELS GENERALLY TRENDING SLIGHTLY SLOWER
AND FARTHER SE THAN 06Z RUNS WITH TRACK OF SFC LOW. MODELS INDICATE
WARM AIR ADVECTION AND ISENTROPIC ASCENT ALONG AND AHEAD OF THE LOW
AND INVERTED SFC TROUGH SHOULD SUPPORT EXPANDING SNOW SHIELD FM
CNTRL MINNESOTA INTO NORTHWEST WI LATE TONIGHT THROUGH DAYBREAK ON
WEDNESDAY. THIS SNOW SHIELD WILL THEN SPREAD INTO WEST AND CENTRAL
UPPER MI DURING THE DAY ON WEDNESDAY. AS SFC TROUGH EDGES CLOSER TO
UPR MICHIGAN WED AFTN ISENTROPIC ASCENT BECOMES MAXIMIZED ON
285-290K SFCS ACROSS UPR MICHIGAN FROM 15Z INTO WED EVENING. GFS
REMAINS QUICKEST OF 12Z MODELS WHILE THE ECMWF IS THE SLOWEST. THE
NAM AND REGIONAL GEM FALL SOMEWHERE BTWN THESE SOLNS. H7 MIXING
RATIOS IN 2.5-3 G/KG RANGE SUGGESTS 12 HOUR SNOW AMOUNTS 4-6 INCHES
OVER MAINLY THE WEST HALF COUNTIES. IT/S POSSIBLE ACTUAL SNOW
AMOUNTS ON WED COULD BE HELD DOWN SOME AS SNOW ARRIVES DURING THE
DAYTIME WHEN INSOLATION COULD LIMIT ACCUMS ESPECIALLY ON HIGHER
TRAFFIC/TRAVELLED ROADS. CROSS SECTIONS SUGGEST POSSIBILITY OF
HEAVIER BANDED SNOWFALL OVER WESTERN COUNTIES WITH NEG EPV ABOVE
FAIRLY STRONG 7H FGEN FORCING SO THIS COULD ADD A FEW INCHES TO THE
4-6 INCH TOTALS RENDERED SOLELY FM ISENTROPIC ASCENT.

WITH ALL ABOVE FACTORS TAKEN INTO CONSIDERATION...HAVE DECIDED TO
UPGRADE WATCHES OVER THE WEST HALF COUNTIES TO WARNINGS FROM
MQT-DICKINSON WESTWARD. GENERALLY STARTED WARNINGS ON WED FM 14Z
SOUTH TO 16Z NORTH. ALSO MOVED THE AXIS OF HEAVIER PCPN/SNOWFALL
SLIGHTLY FARTHER EASTWARD BASED ON 12Z MODEL TRENDS WITH SNOWFALL
AMOUNTS ON WED RANGING FM 3 TO 5 INCHES OVER THE NW CWA TO 4-7
INCHES OVER THE FAR SW CWA ALONG THE WI BDR. WENT WITH ADVISORIES
FOR MNM...DELTA AND ALGER COUNTIES WHERE 2-4 INCH AMOUNTS WILL BE
MORE COMMON ON WED WITH MUCH OF THE SNOW FALLING IN THE AFTERNOON
HRS. FARTHER EAST OVER SCHOOLCRAFT AND LUCE COUNTIES...LOW-LVL DRY
AIRMASS INITIALLY IN PLACE FROM LINGERING SFC RDG AXIS WILL TAKE A
BIT LONGER TO MOISTEN FM ISENTROPIC ASCENT SO ONLY EXPECT GENERALLY
1-2 INCHES OF SNOW THERE AND WILL HOLD OFF ON ANY HEADLINE THERE FOR
NOW. IF TONIGHT/S MODEL RUNS CONTINUE TO TREND EASTWARD MAY NEED TO
CONSIDER POSSIBILITY OF ADDING MNM AND POSSIBLY DELTA INTO
WARNING.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 531 PM EDT TUE APR 15 2014

LONG TERM PORTION OF THE FCST WILL BEGIN COLD/WINTRY AS SHORTWAVE
TAKES ADVANTAGE OF LINGERING TIGHT THERMAL GRADIENT OVER THE AREA
BTWN DEPARTING UNUSUALLY COLD AIR MASS FOR MID APR AND WARMTH
SPREADING OUT ACROSS THE CNTRL/SRN PLAINS. TEMPS WILL THEN SLOWLY
MODERATE AS DEEP TROF AND ASSOCIATED LATE SEASON ARCTIC AIR LIFT TO
GREENLAND...AND PACIFIC AIR MAKES INCREASING INROADS ACROSS THE
CONUS AND SRN CANADA. HEADING DOWN THE ROAD...IT LOOKS LIKE TEMPS
NEXT WEEK WILL GENERALLY FLUCTUATE AROUND NORMAL...BUT NOT
SIGNIFICANTLY ABOVE OR BLO NORMAL DURING THE TEMP SWINGS. THERE ARE
SOME INDICATIONS FROM GEM ENSEMBLES AND GFS RUNS THAT THE PATTERN
MAY BE FAIRLY ACTIVE OVER THE NEXT COUPLE OF WEEKS WHICH WILL MEAN
RAINFALL FOR MOST IF NOT ALL PCPN EVENTS. HOPEFULLY...SIGNIFICANT
RAINFALL WILL BE AVOIDED AS THE SNOWMELT SEASON RESUMES.

BEGINNING WED NIGHT...A HVY/WET SNOW EVENT WILL BE UNDERWAY AS
SHORTWAVE APPROACHES FROM THE UPPER MISSISSIPPI VALLEY. WITH 12Z
MODEL RUNS...MODELS THAT HAD MAX QPF AXIS ON THE NW SIDE OF THE
MODEL SPREAD HAVE SHIFTED SLIGHTLY S AND E. RESULT IS IMPROVING
MODEL AGREEMENT NOW ON WHERE AXIS OF HEAVIEST PCPN WILL SET UP. IT
APPEARS MAX QPF AXIS SHOULD RUN ROUGHLY FROM JUST N OF THE TWIN
CITIES TO THE HURON MTNS. THE NAM IS DISPLACED A LITTLE TO THE NW OF
THIS AXIS WHILE THE GEM REGIONAL/HEMISPHERIC ARE DISPLACED A LITTLE
TO THE SE. ALTHOUGH SFC LOW ASSOCIATED WITH SHORTWAVE WILL BE
WEAKENING AS IT TRACKS FROM THE NRN/CNTRL PLAINS TO THE UPPER
LAKES...BEST COMBINATION OF FORCING/MOISTURE WILL COME TOGETHER FROM
ERN MN E AND NE NTO UPPER MI BEFORE SYSTEM BEGINS TO FALL APART. AT
THE UPPER LEVELS...RIGHT ENTRANCE OF UPPER JET STREAK RUNNING FROM
NRN LAKE SUPERIOR/NRN ONTARIO EASTWARD WILL PROVIDE HEALTHY UPPER
DIVERGENCE. THERE ARE EVEN SOME HINTS OF BRIEF UPPER JET COUPLING
WITH LEFT EXIT OF JET SHIFTING ACROSS THE UPPER MIDWEST THAT IS
SUPPORTING THE SHORTWAVE. AT THE LOWER LEVELS...STRONG ISENTROPIC
ASCENT IS NOTED WITH MIXING RATIOS OF 3 TO 4G/KG AVBL AROUND
700-750MB. IN ADDITION...THERE IS STRONG FRONTOGENESIS WITH NEGATIVE
EPV/CONVECTIVE INSTABILITY NOTED OVERTOP THE FGEN. FINALLY...STEEP
MIDLEVEL LAPSE RATES ARE NOTED ADVECTING INTO THE SRN SIDE OF THE
PCPN AREA. ALL THIS POINTS TO THE LIKELIHOOD FOR HEAVIER BANDING OF
SNOW WITHIN THE OVERALL MDT/HVY PCPN AREA OR EVEN CONVECTIVE SNOW AT
TIMES...CERTAINLY NOT ATYPICAL FOR SPRINGTIME HVY SNOW EVENTS.
ULTIMATE PLACEMENT OF HEAVIEST SNOW WILL HINGE ON WHERE THESE
HEAVIER SNOWBANDS OR CONVECTIVE ELEMENTS SET UP. AS IT STANDS
NOW...LOCATIONS W OF KIMT/KMQT LINE SHOULD HAVE NO PROBLEM REACHING
WARNING CRITERIA WITH STORM TOTAL AMOUNTS AROUND 1 FOOT...PROBABLY
IN MANY LOCATIONS. ADVY ISSUED FOR NEXT TIER OF COUNTIES E MAY IN
FACT NEED TO BE UPGRADED TO WARNINGS GIVEN MODEL TRENDS. FINALLY...
EVEN THE FAR E COUNTIES OF SCHOOLCRAFT AND LUCE MAY NEED TO BE ADDED
TO AN ADVY IF THE E TREND HOLDS UP IN NEXT SET OF MODEL RUNS.

PCPN WINDS DOWN QUICKLY THU AND WILL LIKELY END. SFC HIGH PRES THEN
BUILDS INTO THE UPPER LAKES THU NIGHT THRU FRI NIGHT TO PROVIDE A
PERIOD OF QUIET WEATHER. NAM IN PARTICULAR SUGGESTS LOW CLOUDS MAY
LINGER THU NIGHT...AND THAT MAY BE THE CASE WITH SHALLOW COLD AIR
MASS OVER EXPANDING OPEN WATER ON LAKE SUPERIOR. IF CLOUDS DO CLEAR
OUT IN SOME AREAS THU NIGHT...EXPECT BKN DIURNAL CU DEVELOPMENT FRI
UNDER MID LEVEL TROF AND ASSOCIATED THERMAL TROF. NOT OUT OF THE
QUESTION THAT A FEW FLURRIES COULD EVEN DEVELOP. FRI HIGHS WILL BE
IN THE 30S N WITH A CHILLY WIND OFF THE ICE TO THE 40S S. WITH
CLOUDS CLEARING OUT FRI NIGHT...IT WILL BE A COLD NIGHT WITH HIGH
PRES STILL OVER THE AREA. FAVORED THE LOWER SIDE OF GUIDANCE WITH
SOME TEENS OVER THE W WHERE WINDS WILL BE LIGHTEST. COULD BE
CONSIDERABLY COLDER ACROSS ALL OF THE INTERIOR IF SKIES CLEAR EARLY
AND STAY THAT WAY FOR A GOOD PART OF THE NIGHT.

MODELS THEN DIVERGE WITH PROGRESSION OF NEXT SHORTWAVE FEATURE
MOVING OFF THE PACIFIC IN LOWER AMPLITUDE FLOW...THOUGH AGREEMENT IS
IMPROVING WITH TODAYS 12Z MODEL RUNS. GEM IS STRONGER WITH WAVE AND
IS HEAVIER WITH THE QPF THAN THE GFS/ECWMF. HOWEVER...BOTH THE GFS
AND ECMWF ARE TRENDING TOWARD A WETTER SYSTEM NOW. SOME -RA POSSIBLY
MIXED WITH A LITTLE SNOW OVER HIGHER TERRAIN WILL PROBABLY REACH THE
W SAT AFTN...THEN SPREAD E SAT NIGHT/SUN. WITH WETTER TRENDS
NOTED...WILL TRENDING POPS UP TO CHC.

MON/TUE...ECMWF HAS BEEN CONSISTENT SHOWING TROF DEVELOPMENT INTO
THE W COAST WITH DOWNSTREAM RIDGE BUILDING INTO THE ROCKIES/WRN
PLAINS WHILE TROF SETTLES INTO THE ERN CONUS. THE GFS IS
CONSIDERABLY MORE PRONOUNCED WITH EASTWARD EXTENT OF RIDGE/HIGHER
HEIGHTS INTO THE GREAT LAKES...BUT THE 12Z GFS IS NOW SHOWING SIGNS
OF HEADING IN THE DIRECTION OF THE ECMWF. WILL LEAN TOWARD THE MORE
CONSISTENT ECMWF WHICH TYPICALLY VERIFIES BETTER. RESULT IS A COOLER
THAN GFS SCENARIO...BUT STILL CLOSE TO NORMAL FOR TEMPS. IF ANY
MINOR WAVES TRACK SE ACROSS THE AREA INTO THE ERN TROF...THERE MAY
BE SOME SCT LIGHT -SHRA AT TIMES. AT THIS POINT...NOTHING SUGGESTS
THE NEED FOR AN EXPLICIT MENTION OF PCPN MON OR TUE.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 741 PM EDT TUE APR 15 2014

HIGH PRESSURE BUILDING IN ACROSS THE U.P. WILL HELP TO KEEP WINDS
LIGHT AND VARIABLE THROUGH TONIGHT. ANY LINGERING DIURNAL SNOW
SHOWERS WILL QUICKLY DISSIPATE THIS EVENING. ALL SITES EXCEPT FOR
THE KSAW TAF SITE HAVE CLEARED OUT AS OF 00Z/15. DURING THE DAY
WEDNESDAY...ATTENTION WILL TURN TO AN APPROACHING LOW PRESSURE
SYSTEM. IWD WILL BE THE FIRST TO SEE THE SNOWFALL AROUND 14Z...THEN
THE SNOW WILL SPREAD TO CMX AND KSAW THROUGH THE REMAINDER OF THE
DAY. HAVE TRENDED THE VISIBILITY LOWER TOWARD THE END OF THE TAF
PERIOD AS HEAVIER SNOW AND STRONGER WINDS BEGIN TO PUSH INTO EACH OF
THE TAF SITES. IWD WAS KEPT A BIT LOWER THAN THE OTHER TAF SITES AS
THE HEAVIER SNOW WOULD APPROACH THAT AREA FIRST.
ADDITIONALLY...CEILING HEIGHTS WILL DECREASE AS THE UPPER LEVEL
TROUGH AND MAIN SURFACE LOW MOVE CLOSER TO THE REGION TOWARD THE END
OF THE TAF PERIOD.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 531 PM EDT TUE APR 15 2014

WINDS LESS THAN 20 KTS THROUGH TONIGHT WITH SFC HIGH PRES RIDGE OVER
THE AREA. APPROACHING LOW PRESSURE SYSTEM FM THE PLAINS WILL RESULT
IN INCREASING EAST TO NORTHEAST WINDS ON WEDNESDAY. WENT WITH A GALE
WARNING FOR FAR WRN LAKE SUPERIOR WEDNESDAY AFTN INTO THU MORNING AS
WINDS ARE ENHANCED DUE TO CHANNELING AND TERRAIN EFFECTS. WINDS
SHIFT TO THE NORTH-NORTHWEST TO 25 KTS BY THURSDAY AFTERNOON AS THE
LOW WEAKENS WHILE MOVING OVER ERN LK SUPERIOR. EXPECT WINDS STAY BLO
20 KTS FOR THE REST OF THE FORECAST PERIOD.
&&

.HYDROLOGY...
ISSUED AT 531 PM EDT TUE APR 15 2014

RECENT COLDER WEATHER AND CONTINUATION OF COLDER WEATHER FOR THE
NEXT FEW DAYS WILL RESULT IN SLOW RUNOFF OF MELTING SNOW. THUS...
RIVER LEVELS SHOULD NOT SHOW ANY SIGNIFICANT FLUCTUATIONS.
HOWEVER...ICE JAMS COULD BE AN ISSUE AS THEY HAVE BEEN IN SOME
AREAS. HOWEVER...DIMINISHED RUNOFF SHOULD REDUCE THE POTENTIAL FOR
ADDITIONAL ICE JAMS. WIDESPREAD PRECIPITATION IS IN THE FORECAST FOR
WEDNESDAY THROUGH THURSDAY MORNING WITH THE POTENTIAL FOR 0.50 TO
1.25 INCHES OF LIQUID EQUIVALENT PRECIPITATION...GREATEST OVER THE W
HALF OF UPPER MICHIGAN. THIS PRECIP ADDED TO EXISTING SNOWPACK WITH
WATER EQUIVALENT OF 4-9 INCHES WILL RESULT IN ANOTHER PERIOD OF
SNOWMELT RUNOFF/RIVER RISES AND POSSIBLE ICE JAMS ONCE WARMER
TEMPERATURES ARRIVE NEXT WEEK.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  WINTER WEATHER ADVISORY FROM NOON WEDNESDAY TO NOON EDT THURSDAY
     FOR MIZ006-013.

  WINTER STORM WARNING FROM NOON WEDNESDAY TO 11 AM EDT THURSDAY
     FOR MIZ004-084.

  WINTER STORM WARNING FROM NOON WEDNESDAY TO NOON EDT THURSDAY
     FOR MIZ005.

  WINTER STORM WARNING FROM 11 AM EDT /10 AM CDT/ WEDNESDAY TO 11
     AM EDT /10 AM CDT/ THURSDAY FOR MIZ002-009>011.

  WINTER STORM WARNING FROM 2 PM WEDNESDAY TO NOON EDT THURSDAY
     FOR MIZ001-003.

  WINTER WEATHER ADVISORY FROM 9 AM WEDNESDAY TO 10 AM CDT
     THURSDAY FOR MIZ012.

LAKE SUPERIOR...
  GALE WARNING FROM 2 PM EDT /1 PM CDT/ WEDNESDAY TO 11 AM EDT /10
     AM CDT/ THURSDAY FOR LSZ162.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...VOSS
LONG TERM...ROLFSON
AVIATION...KEC
MARINE...VOSS
HYDROLOGY...ROLFSON







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