Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 281937
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
337 PM EDT SAT MAR 28 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 337 PM EDT SAT MAR 28 2015

UPPER AIR PATTERN CONSISTS OF A DEEP 500 MB TROUGH OVER THE ERN U.S.
THIS MORNING WITH A SHORTWAVE RIDGE ACROSS THE ROCKIES AND A
SHORTWAVE IN THE PACIFIC NW. THIS RIDGE MOVES INTO THE UPPER GREAT
LAKES TONIGHT WHILE THE SHORTWAVE MOVES INTO THE NORTHERN PLAINS AND
THEN THE SHORTWAVE MOVES THROUGH THE UPPER GREAT LAKES ON SUN.

NAM BRINGS IN SOME 850-500 MB Q-VECTOR CONVERGENCE TONIGHT WITH
DEEPER MOISTURE COMING IN LATE TONIGHT. THE MOISTURE STARTS TO HEAD
OUT LATE SUN AFTERNOON WITH Q-VECTOR DIVERGENCE MOVING IN BY SUN
EVENING. GFS AND ECMWF SHOW ABOUT THE SAME THING AS WELL.

QUIET FORECAST FOR TONIGHT AS PCPN HOLDS OFF UNTIL SUNDAY AND THEN
FORECAST BECOMES COMPLICATED IN A HURRY. WILL HAVE VERY DRY AIR
ALOFT TO WORK THROUGH FIRST AND HELD OFF ON THE PCPN UNTIL 12Z
SUNDAY OVER THE WEST AND INCREASED POPS  SUNDAY MORNING TO
CATEGORICAL. LOOKED AT NUMEROUS SOUNDINGS FOR MIXED PCPN AND LOOKED
TO ME LIKE THE MAJORITY OF THE PCPN WOULD STAY AS SNOW ESPECIALLY
ACROSS THE EAST HALF OF THE CWA AS WET BULB ZERO HEIGHTS STAY LOW
WITH PLENTY OF EVAPORATION TO COOL THE SOUNDINGS ALL BELOW ZERO.
EVEN IF THERE IS SOME WARM AIR ALOFT WHICH THE NAM IS THE MOST
AGGRESSIVE WITH...FEELING IS THAT WITH THE DRY AIR TONIGHT...WOULD
COOL THIS BACK BELOW WET BULB ZERO.

THE WARM AIR TRIES TO MAKE IT INTO THE WEST IN THE AFTERNOON...BUT
BY THAT TIME...THE DEEPER MOISTURE IS MOVING OUT AND THERE COULD BE
A RAIN/SNOW MIX IN THE WEST IN THE AFTERNOON. OVER THE EAST...THE
PCPN WILL STAY AS ALL SNOW AND COULD SEE A QUICK 3-6 INCHES OF SNOW
OVER SCHOOLCRAFT AND LUCE COUNTIES AND FOR THAT REASON WENT WITH A
WINTER WEATHER ADVISORY FOR THEM FROM LATE SUNDAY MORNING INTO
SUNDAY EVENING. TOTAL QPF FOR THIS EVENT LOOKS TO BE FROM 0.20 TO
0.35 INCH WITH SNOW RATIOS FAIRLY LOW IN A WET AND HEAVY SNOW. FOR
TEMPERATURES...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST.
USED A NON DUIRNAL TEMPERATURE CURVE FOR TONIGHT WITH LOWS SHORTLY
AFTER MIDNIGHT...THEN TEMPS SLOWLY WARMING AND HIGHS ON SUNDAY WILL
BE LATE IN THE DAY.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 506 AM EDT SAT MAR 28 2015

A DEEP TROUGH OVER THE ERN CONUS WILL GIVE WAY TO A MORE ZONAL
PATTERN THAT WILL ALLOW A SERIES OF SHORTWAVES TO MOVE FROM THE
PACIFIC NW THROUGH SRN CANADA AND THE GREAT LAKES. THIS WILL BRING
MILDER WEATHER INTO THE AREA BUT WITH SEVERAL CHANCES FOR PCPN FROM
SUN THROUGH THE MIDDLE OF NEXT WEEK.

SUNDAY...A VIGOROUS PACIFIC SHORTWAVE WILL MOVE INTO NRN ONTARIO AND
THE NRN LAKES SUNDAY. 700-300 MB QVECTOR CONV ASSOCIATED WITH THIS
FEATURE WILL BE STRONG ENOUGH TO PRODUCE QPF AMOUNTS AT LEAST INTO
THE 0.15-0.30 INCH RANGE. FCST SOUNDINGS SUGGEST THAT PCPN WILL FALL
AS SNOW IN THE MORNING AND MAY CHANGE TO RAIN OVER THE WEST HALF
AS THE STRONGER LIFT DEPARTS IN THE AFTERNOON. A QUICK INCH OR TWO
WILL BE POSSIBLE OVER MUCH OF UPPER MICHIGAN WITH SLIGHTLY GREATER
AMOUNTS TO AROUND 3 INCHES POSSIBLE FROM ISQ AND SENEY TO ERY. IN
ADDITION...A TIGHT PRES GRADIENT ASSOCIATED WITH A 990 MB SFC LOW
MOVING THROUGH NRN ONTARIO WILL PRODUCE GUSTY SSW WINDS AHEAD OF THE
LOW VEERING TO THE WNW BEHIND THE TROUGH. EVEN THOUGH A 900 MB LOW
LEVEL JET OVER AOA 60 KT IS FCST DURING THE MORNING...LOW LEVEL
STABILITY WILL BE STRONG ENOUGH SO THAT MIXING TOWARD THE SFC RESULTS
IN MORE MODERATE GUSTS IN THE 20-30 MPH RANGE. HOWEVER...LOCATIONS
NEAR THE LAKE MICHIGAN SHORELINE MAY SEE GUSTS TO AROUND 40 MPH. A
PERIOD OF GUSTY WRLY WINDS WILL ALSO BE POSSIBLE DURING THE LATE
AFTERNOON AND EVENING...ESPECIALLY OVER THE HIGHER TERRAIN OF THE
KEWEENAW...AS THE STRONGER ISALLOBARIC COMPONENT MOVES THROUGH.

SUN NIGHT...SOME ADDITIONAL LIGHT SNOW/RAIN SHOWERS MAY BE POSSIBLE
IN THE CYCLONIC NW FLOW AROUND THE DEPARTING LOW AS A TRAILING
SHORTWAVE MOVES THROUGH DURING THE EVENING. EXPECT LIGHT SNOW
SHOWERS TO DIMINISH OVERNIGHT AS THE DEEPER MOISTURE DEPARTS TO THE
EAST.

MON...ANY LINGERING LIGHT SNOW SHOWERS OR FLURRIES WILL END BY
AFTERNOON LEAVING PARTLY SUNNY SKIES. THIS WILL ALLOW TEMPS TO CLIMB
INTO THE UPPER 30S NORTH AND EAST TO THE MID 40S SOUTH AND WEST.

MON NIGHT AND TUE...THE MODELS HAVE COME INTO BETTER AGREEMENT WITH
THE POTENTIAL FOR A CLIPPER SHORTWAVE MOVING THROUGH THE NRN LAKES
THAT COULD PRODUCE A NARROW BAND OF MODERATE SNOW. HOWEVER...THERE
IS GREATER UNCERTAINTY WITH THE LOCATION OF ANY HEAVIER SNOWBAND
GIVEN MODELS VARIABILITY OVER THE LAST SEVERAL RUNS.

WED-FRI...MODELS SUGGEST THAT ANOTHER STRONGER SHORTWAVE AND SFC LOW
WILL MOVE INTO THE NRN LAKES WITH AN ASSOCIATED AREA OF WAA PCPN
INTO UPPER MI BY LATE WED OR WED NIGHT. GIVEN THE TREND TOWARD AN
INFLUX OF WARMER AIR...MAINLY RAIN IS EXPECTED. ABOVE AVERAGE MAX
TEMPS FROM THE MID 40S TO MID 50S SHOULD DROP BACK BY THE END OF THE
WEEK. WITH LARGE MODEL SPREAD/VARIABILITY BY FRI...UNCERTAINTY IS
HIGH WITH THE EVOLUTION/SPEED OF THE TROUGH MOVING THROUGH THE CNTRL
CONUS AND ASSOCIATED PCPN CHANCES.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 117 PM EDT SAT MAR 28 2015

WINDS WILL INCREASE BETWEEN A DEPARTING HIGH PRESSURE SYSTEM AND A
LOW PRESSURE SYSTEM MOVING ACROSS SOUTHERN CANADA. THE RESULT WILL
BE LLWS AT ALL SITES TONIGHT AND GUSTY SSW SURFACE WINDS.
PRECIPITATION LOOKS TO MOVE IN AT ALL SITES SUN MORNING AND
CONDITIONS WILL QUICKLY DETERIORATE TO IFR BY LATE MORNING WITH
LOWER VIS IN THE SNOW. THERE COULD BE SOME RAIN MIXED IN WITH IT AT
IWD.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 337 PM EDT SAT MAR 28 2015

STRONG SOUTHWEST WINDS EXPECTED LATE TONIGHT THROUGH SUNDAY NIGHT AS
LOW PRESSURE SYSTEM CROSSES MANITOBA AND NORTHERN ONTARIO. SOUTHWEST
GALES POSSIBLE WITH THIS SYSTEM ON SUN...ESPECIALLY ON THE EAST
HALF. NORTHWEST GALES POSSIBLE SUNDAY NIGHT INTO MONDAY IN WAKE OF
THE LOW PRESSURE SYSTEM AND TROUGH. SERIES OF LOW PRESSURE TROUGHS
CROSS LAKE SUPERIOR THROUGH THE REST OF NEXT WEEK...BUT WINDS ARE
EXPECTED TO STAY MAINLY BELOW 20 KTS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  WINTER WEATHER ADVISORY FROM 11 AM TO 11 PM EDT SUNDAY FOR
     MIZ007-014-085.

LAKE SUPERIOR...
  GALE WARNING FROM 8 AM SUNDAY TO 5 AM EDT MONDAY FOR LSZ249>251-
     266-267.

  GALE WARNING FROM 2 AM EDT /1 AM CDT/ TO 11 AM EDT /10 AM CDT/
     SUNDAY FOR LSZ162-263.

LAKE MICHIGAN...
  GALE WARNING FROM 2 AM TO 8 PM EDT SUNDAY FOR LMZ221-248-250.

&&

$$

SHORT TERM...07
LONG TERM...JLB
AVIATION...07
MARINE...07



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