Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 200540
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1240 AM EST SAT DEC 20 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 321 PM EST FRI DEC 19 2014

WITH A 1028MB SFC RIDGE OVERHEAD...SNOW SHOWERS RESULTING FROM WAA
AND A WEAK SHORTWAVE HAVE BEEN DISSIPATING OVER WRN LAKE SUPERIOR
AND NWRN WI THIS AFTERNOON/EARLY EVENING. WE MAY SEE SOME FLURRIES
NEAR IRONWOOD THIS AFTERNOON...BUT NOT EXPECTING ANY MEASURABLE
AMOUNTS. OTHERWISE...THE SFC RIDGE WILL PUSH E OF THE CWA TONIGHT AS
AN UPPER TROUGH SLOWLY MOVES TO JUST W OF THE CWA BY 00Z SUN. NOT
MUCH IN THE WAY OF MOISTURE OR FORCING WITH THE TROUGH...SO THINK
SNOW SHOWERS WILL STAY CONFINED TO THE MN ARROWHEAD AND FAR WRN LAKE
SUPERIOR THROUGH 00Z SUN.

PRETTY QUIET FORECAST SHIFT OVERALL...MAINLY JUST LOOKING AT SKY
COVER TRENDS WITH THE PESKY LOW LEVEL CLOUDS...WHICH IS PAR FOR THE
COURSE LATELY. THINK ENOUGH CLEARING WILL OCCUR OVER THE CENTRAL CWA
TO ALLOW PATCHY FOG TO DEVELOP AS TEMPERATURES DROP TONIGHT. COLDEST
TEMPS EXPECTED OVER THE ERN CWA WHERE LOWS SHOULD BE AROUND 0C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 254 PM EST FRI DEC 19 2014

NAM SHOWS A 500 MB TROUGH OVER THE UPPER GREAT LAKES 00Z SUN WITH A
CLOSED LOW OVER WESTERN ONTARIO WITH A SHORTWAVE OVER THE CANADIAN
PRAIRIES. THIS SHORTWAVE DIGS SOUTHEAST AND FORMS A CLOSED 500 MB
LOW OVER THE UPPER MISSISSIPPI RIVER VALLEY 00Z TUE.

KEPT SAT NIGHT THROUGH SUN MORNING DRY WITH PCPN OFF TO THE WEST AND
NORTHWEST OF THE AREA AND THEN START TO BRING IN SOME SLIGHT CHANCES
FOR SNOW SUN AFTERNOON AND THEN START TO BRING IN SOME CHANCE POPS
FOR SUN NIGHT INTO MONDAY. DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST FOR TEMPERATURES. DID KEEP IN SOME RAIN/SNOW MIX FOR
MONDAY AFTERNOON.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW NEARING THE
UPPER GREAT LAKES 12Z TUE EMBEDDED IN A TROUGH OVER THE PLAINS
STATES. THE TROUGH AND UPPER LOW MOVE SLOWLY EAST 12Z WED AND ARE
EAST OF THE AREA INTO THE LOWER GREAT LAKES 12Z THU FOLLOWED BY
SHORTWAVE RIDGING OVER THE PLAINS. THIS RIDGING MOVES INTO THE UPPER
GREAT LAKES 12Z FRI. THIS SYSTEM FOR MONDAY NIGHT INTO THURSDAY IS
STILL NOT WELL HANDLED BY THE MODELS. THE ECMWF CONTINUES WITH A
FURTHER SOUTH TRACKING OF THE SFC LOW WHICH WOULD GIVE US COLDER AIR
AND MORE SNOW WHILE THE GFS TRACK IS FURTHER NORTH. THERE IS ALSO A
QUESTION OF IF THIS SYSTEM WILL GO FURTHER SOUTH AND EAST AND TURN
INTO AN EAST COAST STORM RATHER THAN A GREAT LAKES STORM. LOOKING AT
THE NEW ECMWF...IT CONTINUES TO GO WITH A GREAT LAKES SYSTEM...BUT
THE 500 MB TROUGH BECOMES VERY NEGATIVELY TILTED. HAVE A FEELING THE
FURTHER SOUTH AND EAST SOLUTION MAY VERIFY WITH THE EAST COAST STORM
THOUGH AND HOPEFULLY LATER MODEL RUNS WILL BE ABLE TO FIGURE THIS
OUT. WILL CONTINUE TO HIGHLIGHT THIS IN THE HWO FOR NOW AS THE PCPN
TYPE AND SNOW AMOUNTS ARE HIGHLY DEPENDENT ON THE TRACK TO THE SFC
LOW AND THERE WILL BE SOME LAKE ENHANCEMENT TO THE SNOW AS WELL.
TEMPERATURES WILL BE ABOVE NORMAL FOR THIS FORECAST PERIOD. BUMPED
UP WINDS IN THE EXTENDED FROM 06Z THU ONWARD AS PRESSURE GRADIENT
TIGHTENS.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1239 AM EST SAT DEC 20 2014

LOW CLOUD FCST MAY BE TRICKY TONIGHT AT KSAW AS LATEST SATELLITE
IMAGERY REVEALS AN AREA OF CLEARING OVER CNTRL UPPER MI. ALSO SEEING
FOG DEVELOP IN LAST HR THERE AS WELL...SO AS LONG AS SKIES STAY
CLEAR...WILL HAVE FOG ISSUES. DUE TO THE BKN MID CLOUDS LURKING
JUST TO THE WEST OF KSAW AND INCREASING HIGH CLOUDS...HAVE FEELING
THAT FOG WILL BE IN AND OUT AND NOT A PREVAILING CONDITION SO JUST
INCLUDED IN TEMPO. MODEL GUIDANCE SUGGESTS THAT KSAW COULD STAY CLR
OF BKN-OVC LOW CLOUDS THROUGH THE MORNING HRS BEFORE CLOUDING BACK
UP AGAIN WITH AN MVFR DECK BY THIS AFTN.

FOR THE WESTERN TAF SITES...EXPECT LOW CLOUDS TO PERSIST THROUGH
MUCH OF PD AS WARM AIR AND MOISTURE ADVECTION CONTINUES TO ADVECT
OVER AREA BETWEEN A HIGH PRESSURE SYSTEM TO THE EAST AND A TROUGH
OVER THE NORTHERN PLAINS. ONLY EXCEPTION WILL BE EARLY ON AT KCMX
WHERE ONLY MID CLOUDS ARE NOTED TO START THIS TAF PERIOD.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 321 PM EST FRI DEC 19 2014

EXPECT LIGHT WINDS UNDER 20 KTS ASSOCIATED WITH HIGH PRESSURE
PASSING THROUGH THE UPPER LAKES TONIGHT TO SHIFT TO THE S BUT REMAIN
UNDER 20 KTS UNTIL AT LEAST SUN. THE S WINDS MAY INCREASE UP TO 25
KTS OVER MAINLY THE E HALF OF THE LAKE LATER SUN INTO MON IN ADVANCE
OF AN APPROACHING LOW PRESSURE SYSTEM. AS ANOTHER LOW PRESSURE
DEVELOPS TO THE S...THE FLOW WILL TEND TO BACK AND WEAKEN ON TUE.
DEPENDING ON HOW QUICKLY THIS SECOND LOW DEVELOPS AND WHERE IT
TRACKS...THERE COULD BE A NW GALE EVENT ON CHRISTMAS DAY.
&&

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

$$

SHORT TERM...TITUS
LONG TERM...07
AVIATION...JLA
MARINE...TITUS






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