Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 190639
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
239 AM EDT TUE MAY 19 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 359 PM EDT MON MAY 18 2015

WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NW ONTARIO INTO THE WRN GREAT LAKES WITH THE LOW CIRCULATION CENTER
NEAR CYQT. AT THE SFC...A TROUGH EXTENDED THROUGH NRN LAKE SUPERIOR
FROM LOW PRES E OF LAKE SUPERIOR. WITH THE WRAP-AROUND MOISTURE/PCPN
MOVING EDGING TOWARD THE AREA...RADARS INDICATED DIURNALLY ENHANCED
SCT/NMRS -SHSN/SHRA FROM NE MN INTO NW WI. SOME LIGHT RAIN OR
DRIZZLE HAD ALSO DEVELOPED INTO UPSLOPE FLOW LOCATIONS OF NW UPPER
MI.

TONIGHT...THE COMBINATION OF DEEP MOISTURE SLIDING INTO THE AREA
BEHIND THE MID LEVEL LOW AND CAA DROPPING 850 MB TEMPS INTO THE -8C
TO -11C RANGE WILL SUPPORT SCT/NMRS -SHRA/-SHSN INTO MAINLY THE WEST
HALF OF UPPER MI. THE MOST FAVORABLE UPSLOPE FLOW AND LOW LEVEL CONV
WILL SHIFT TO LOCATIONS OVER THE W FAVORED BY NRLY FLOW AND INTO N
CNTRL UPPER MI LATE. LOW LEVEL THICKNESS AND WET-BULB ZERO HEIGHTS
SUGGEST ANY PCPN WILL CHANGE OVER TO MAINLY SNOW FROM WEST TO EAST
THIS EVENING. ALTHOUGH QPF AMOUNTS TO AROUND A TENTH OF AN INCH ARE
EXPECTED...WITH THE RELATIVELY WARM GROUND...ANY SNOWFALL AMOUNTS
SHOULD REMAIN AROUND A HALF INCH OR LESS...MAINLY ON GRASSY SURFACES.

TUE...AS HIGH PRES BUILDS TOWARD THE AREA WITH INCREASINGLY ACYC
LOW LEVEL FLOW...AND THE DEEPER MOISTURE DEPARTS TO THE EAST...THE
LINGERING SNOW SHOWERS SHOULD GRADUALLY DIMINISH AND END OVER MOST OF
THE CWA BY 18Z. THERE MAY BE SOME LIGHT PCPN LINGERING OVER THE EAST
DURING THE AFTERNOON. CLOUDS WILL ALSO ONLY SLOWLY DISSIPATE FROM
WEST TO EAST DURING THE MID TO LATE AFTERNOON.
OTHERWISE...UNSEASONABLY COLD CONDITIONS ARE EXPECTED WITH HIGHS
ONLY FROM AROUND 40 NORTH TO THE MID AND UPPER 40S SOUTH AND WEST.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 238 AM EDT TUE MAY 19 2015

FROM WEDNESDAY THROUGH THE END OF THE WORK WEEK...A 500MB TROUGH
WILL REMAIN ACROSS THE GREAT LAKES REGION. THE LOW ITSELF WILL GET
AS CLOSE AS JAMES BAY THURSDAY AFTERNOON. AT THE SFC MUCH OF THIS
TIME PERIOD WILL BE MARKED BY A RIDGE OF HIGH PRESSURE EXTENDING
EITHER S CENTRAL CANADA OR THE NORTHERN TO CENTRAL PLAINS. LOOK FOR
THE RIDGE TO BE SUPPRESSED WEDNESDAY AFTERNOON INTO THURSDAY. A W-E
ORIENTED COLD FRONT SET UP JUST N OF LAKE SUPERIOR ACROSS ONTARIO
WILL SINK ACROSS LAKE SUPERIOR WEDNESDAY AFTERNOON...AND UPPER MI
WEDNESDAY NIGHT BEFORE PUSHING ACROSS WI AND LOWER MI DURING THE DAY
THURSDAY.

WEDNESDAY WILL BE DRY...AND EVEN WITH GOOD MIXING WINDS SHOULD STAY
FAIRLY LIGHT AS YOU NEED TO GO ABOVE 500MB TO GET ANYTHING ABOVE
15KTS. THE COLD FRONT SINKING THROUGH WILL BRING SOME MOISTURE TO
THE AREA...BUT IT/S NOT LOOKING LIKE MUCH MORE THAN CLOUD COVER.
MOST MODELS DO SHOW A BETTER CHANCE FOR AT LEAST SPRINKLES JUST S OF
MENOMINEE AND LOWER MI THURSDAY AFTERNOON...BUT NOTHING FOR UPPER
MI. THIS IS HANDLES WELL IN OUR PREVIOUS FCST...SO LIMITED CHANGES
WILL BE NEEDED. ANY REAL WARM UP WILL HAVE TO WAIT UNTIL THE
WEEKEND...AS COOL N WINDS OFF LAKE SUPERIOR AND 850MB TEMPS ON
THURSDAY HOVERING AROUND 2C. 850MB TEMPS MAY GET DOWN TO -3 OR -4C E
BY 12Z FRIDAY...LEADING TO ANOTHER CHILLY MORNING. OVERNIGHT LOWS IN
THE 30S WILL BE COMMON BOTH WEDNESDAY NIGHT AND THURSDAY NIGHT.

SATURDAY WILL BE A TRANSITION DAY AS THE CANADIAN HIGH EDGES TO THE
SE AND SLIGHTLY WARMER AIR MOVES IN. IT WILL END UP BEING THE
WARMEST DAY THIS WEEK WITH HIGHS NEAR NORMAL /60S TO AROUND 70F/.

THE 500MB RIDGE WILL STRENGTHEN OVER THE CWA SUNDAY AND MONDAY AS
THE SFC RIDGE LINGERS. THE GFS IS A BIT MORE AGGRESSIVE WITH THE MAIN
500MB TROUGH DIGGING BACK INTO THE UPPER GREAT LAKES ON
MONDAY...LEADING TO A STRONGER SYSTEM OVERALL. THE APEX OF THE RIDGE
WILL BE NEARBY AROUND 12Z MONDAY...WITH SW FLOW RETURNING AHEAD OF A
SFC LOW NEARING FROM THE SW. THE BEST CHANCE OF PRECIP IN THIS
LONGER TERM PERIOD WILL LIKELY HOLD OFF UNTIL THE DAYTIME HOURS
MONDAY. THERE IS STILL SOME UNCERTAINTY AS TO WHETHER THE BEST
CHANCE WILL BE OVER THE N OR S...DEPENDING ON THE TRACK/STRENGTH OF
THE SFC LOW AND NEARING SHORTWAVE ENERGY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 122 AM EDT TUE MAY 19 2015

WRAPAROUND MOISTURE IN LIGHT SNOW SHOWERS WILL CONTINUE TO AFFECT
ALL SITES DURING THE EARLY MORNING HOURS WITH IFR TO MVFR CONDITIONS
EXPECTED. SITES WILL BEGIN TO IMPROVE SLIGHTLY TOWARD 12Z BUT WILL
STILL REMAIN MVFR. VFR CONDITIONS WITH MUCH DRIER AIR AND MIXING MOVE
INTO CMX AND IWD THIS AFTERNOON AND WILL TAKE UNTIL THIS EVENING TO
GET VFR AT SAW WHICH WILL STAY MVFR THROUGH THEN.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT MON MAY 18 2015

LOW PRES EAST OF LAKE SUPERIOR WILL CONTINUE TO MOVE TO THE EAST
TONIGHT. A TIGHTENING PRES GRADIENT AHEAD OF HIGH PRES BUILDING
TOWARD THE AREA FROM THE NRN PLAINS WILL BOOST NNW WINDS TO 20 TO 30
KNOTS WITH THE POTENTIAL FOR A FEW GALE FORCE GUSTS OVER THE E HALF
LATE TONIGHT AND TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTERNOON/NIGHT THE HIGH BUILDS IN FM THE WEST. WED THRROUGH
SAT...WINDS WILL BE UNDER 20KT.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

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


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