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000
FXUS63 KMQT 121736
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
136 PM EDT SUN MAY 12 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 549 AM EDT SUN MAY 12 2013

WV IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE/CLOSED LOW SYSTEM
NE OF LAKE SUPERIOR EARLY THIS MORNING. ENHANCEMENT ON THE BACK EDGE
OF THIS SYSTEM COMBINED WITH COLD ADVECTION IN ITS WAKE...HELPED
PRODUCE SOME MODERATE SNOW ACCUMULATION FROM NEGAUNEE/ISHPEMING EAST
THROUGH ALGER AND NRN SCHOOLCRAFT COUNTIES EARLIER THIS MORNING.
HOWEVER...IN THE PAST HR OR TWO RADAR RETURNS HAVE DIMINISHED
DRAMATICALLY IN AREAL EXTENT AND INTENSITY. HERE AT NWS MQT...SNOW
HAS DIMINISHED TO FLURRIES AND EXPECT THIS IS THE CASE AT MANY
LOCATIONS BASED ON RADAR RETURNS. LATEST VAD WIND PROFILE FROM MQT
RADAR ALSO SHOWS INDICATION OF SHARP LOWERING OF SUBSIDENCE
INVERSION FROM 9-10 KFT TO 6 KFT IN PAST HR WHICH IS ALSO CONSISTENT
WITH DIMINISHED RADAR RETURNS.

TODAY...GIVEN RECENT DIMINISHING RADAR TRENDS AND FACT THAT MODELS
SHOW BEST Q-VECT CONV FOR LAKE ENHANCEMENT TO BE MOVING EAST WITH
TIME THIS MORNING...HAVE DECIDED TO CANCEL THE WINTER WEATHER
ADVISORIES FOR NORTH CENTRAL COUNTIES. MOST PLACES FROM MQT COUNTY
EASTWARD WILL BE HARD PRESSED TO SEE MORE THAN HALF AN INCH OF
ADDITIONAL SNOW ACCUMULATION WITH ONLY A FEW LINGERING FLURRIES
NOTED TO THE WEST. UPDATED POPS TO REFLECT SHARP DIMINISHING TREND
TO PCPN THIS MORNING. LINGERING CYCLONIC FLOW AND -10C 8H TEMPS
MOVING ACROSS LAKE SUPERIOR COULD STILL SUPPORT PLENTY OF LAKE
STRATOCU CLOUDS THROUGH THE MORNING HRS...ESPECIALLY FOR
EASTERN COUNTIES DOWNWIND OF LONGER NNW FETCH ACROSS ERN LAKE
SUPERIOR. SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD ALLOW FOR
CLEARING SKIES FROM THE WEST THIS AFTERNOON. FAIRLY TIGHT NW PRES
GRAD ON THE BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR
35 MPH OVER THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.

TONIGHT...GIVEN RELATIVELY COLD HIGH TEMPS EXPECTED TODAY...SFC
RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE W SHOULD ALLOW
SFC TEMPS TO PLUMMET TONIGHT TO RECORD OR NEAR RECORD LOW READINGS
ESPECIALLY OVER THE WRN CWA. LEANED ON THE LOWER END OF MODEL
GUIDANCE FOR MIN TEMPS WITH EXPECTED READINGS IN THE MID TO UPPER
TEENS OVER THE TYPICALLY COLD WRN INTERIOR LOCATIONS AND LOWER TO
MID 20S ACROSS THE REST OF THE INTERIOR CWA. TEMPS WILL STAY A BIT
WARMER NEAR THE GREAT LAKES...GENERALLY IN THE UPPER 20S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 549 AM EDT SUN MAY 12 2013

UPPER PATTERN FEATURING WESTERN CONUS RIDGING AND EASTERN CONUS
TROUGHING BECOMES MORE ZONAL THROUGH THE WEEK...RESULTING IN
WARMING TREND FOR UPPER GREAT LAKES. AS THE UPPER PATTERN BECOMES
MORE ZONAL EXPECT SFC LOW AND FRONTAL BOUNDARIES TO MOVE FROM
CENTRAL CANADA ACROSS THE GREAT LAKES TUESDAY THROUGH THURSDAY. BEST
CHANCE OF RAIN IN THIS PATTERN SHOULD BE LATER TUESDAY THROUGH
TUESDAY NIGHT AS WARM FRONT SLIDES ACROSS UPPER GREAT LAKES. EXTENT
OF COOLING BEHIND COLD FRONT WEDNESDAY INTO THURSDAY UNCERTAIN. EVEN
THE MODELS THAT ARE SHOWING THE MOST EMPHATIC COOLING /GFS AND NAM/
SHOW NOTHING TO THE EXTENT OF CURRENT COOLDOWN THAT IS CURRENTLY
OCCURRING. SO...BEYOND THIS TASTE OF WINTER AFFECTING THE REGION
THIS MORNING...EXPECT EXTENDED TO HOLD ONLY LIQUID PRECIPITATION.

HIGH PRESSURE BEGINS THE EXTENDED PERIOD OVER WESTERN GREAT LAKES.
RIDGE AXIS HEADS ACROSS REST OF GREAT LAKES BY MONDAY NIGHT ALLOWING
WARM AIR ADVECTION/RETURN FLOW TO DEVELOP. THROUGH DAY 2 LEANED ON
THE NAM/GFS SOUNDINGS TO TRY TO GAGE PRECIP CHANCES. MOISTURE
ADVECTION FOCUSED MAINLY ALOFT H85-H7 MONDAY NIGHT. SOME LGT SHOWERS
SEEM LIKELY IN MAX ADVECTION AREA MOVING WEST TO EAST ACROSS CWA.
ONCE MID-LEVEL MOISTURE/LIFT IS STRIPPED AWAY...SHALLOW MOISTURE
MAINLY BLO H9 IS ALL THAT IS LEFT ON TUESDAY. HINTS FROM MODELS THAT
MOISTURE MAY MIX OUT BY AFTN. LOWERED POPS BASED ON LIMITED MOISTURE
INTO TUESDAY AFTN. NEXT SURGE OF MOISTURE/TEMPERATURE ADVECTION AND
ELEVATED INSTABILITY COULD BRING SHOWERS/TSRA OVER GENERALLY WESTERN
CWA LATE TUESDAY AFTN. SE WINDS AHEAD OF WARM FRONT WITH MORE
INFLUENCE OFF LK MICHIGAN FOR MUCH OF CWA SHOULD KEEP TEMPS FROM
GETTING TOO WARM EVEN WITH ONLY SCT CLOUDS BY AFTN. WARMEST READINGS
INTO THE 70S INLAND WEST AND SOUTHWEST CWA WITH LESS LAKE MODIFIED
COOLER AIR. UPR 50S TO UPR 60S ELSEWHERE.

WARM FRONT PASSAGE/MAXIMUM LOW-LEVEL MOISTURE AND TEMP ADVECTION
STILL ON TRACK FOR TUESDAY NIGHT. HAS LOOKED THIS WAY FOR A WHILE
NOW. STILL THINKING THIS IS THE BEST CHANCE FOR SHOWERS AND TSRA
ACROSS CWA...BUT STILL MAY NOT BE WIDESPREAD EVENT FOR ALL CWA. SOME
DIFFERENCE HOW FAR SOUTH SHORTWAVE TROUGH/MID-LEVEL HEIGHT FALLS DIP
INTO UPR LAKES AND THIS IMPACTS SOUTHERN EXTENT OF PRIMARY UPPER
LEVEL JET AND ASSOCIATED DIVERGENCE TO ENHANCE PRECIP. PLACED LIKELY
POPS OVER NORTH AND EAST AND KEPT POPS SCATTERED FARTHER SOUTH. GIVEN
H85 DWPNTS OVER +12C AND 1-6KM MUCAPES OVER 1000J/KG AND SINCE AXIS
OF 925-850MB WIND MAX IS OVERHEAD...SHRA AND TSRA CANNOT BE COUNTED
OUT ANYWHERE THOUGH. STRONGST WINDS ALOFT ARE MORE OVER LAKE SUPERIOR
AND NORTH INTO ONTARIO SO THINK THIS IS WHERE BETTER CHANCE OF
STRONGER STORMS WOULD BE LOCATED. SEEMS THAT LIGHTNING AND HEAVY
DOWNPOURS WILL BE THE PRIMARY HAZARDS. THOUGH WBZERO HEIGHTS
11-12KFT IS ON THE HIGHER SIDE TO SEE LARGE HAIL...IT IS POSSIBLE
GIVEN STRONGER SHEAR AND H7-H5 LAPSE RATES OVER 7C/KM.

GOOD AGREEMENT THAT AREA OF ENHANCED PRECIP SWIFTLY CROSSES THE AREA
LATER TUESDAY NIGHT WITH COLD FRONTAL PASSAGE NOT TOO FAR BEHIND ON
WEDNESDAY MORNING. SUBSTANTIAL CLEARING IN THE OFFING ON WEDNESDAY
IN WAKE OF THE FRONT. 00Z ECMWF TRENDED SLIGHTLY TOWARD COLDER GFS
IDEA FOR H85 TEMPS IN WAKE OF COLD FRONT...BUT EVEN SO...EXPECT
SUNSHINE AND DEEP MIXING TO OFFSET THIS AND LEAD TO MAX TEMPS INTO
THE 70S SOUTHWEST AND SOUTH CENTRAL. READINGS IN THE 60S CLOSER TO
LK SUPERIOR. WINDS MAY END UP STRONGER THAN WHAT CONSENSUS SHOWED
BUT LEFT THEM ALONE FOR NOW. DID GO WITH LOWER BIAS CORRECTED MOS
DWPNTS IN THE AFTN GIVEN THE DEEP MIXING.

THURSDAY AND FRIDAY....A BIT UNSETTLED POTENTIALLY. PRIMARY SFC
FRONTAL BOUNDARY WILL REMAIN SOUTH OF UPR MICHIGAN. YET SINCE THE
AREA IS ON SOUTHERN EDGE OF TROUGH OVR CANADA...THE JET STREAM IS
TOO CLOSE BY TO NOT HAVE AT LEAST SLIGHT CHANCE POPS. MODELS HAVE
SHOWN SOME QPF FROM TIME TO TIME...ESPECIALLY LATER FRIDAY AND
FRIDAY NIGHT AS SECONDARY SFC TROUGH DIPS SOUTH ACROSS THE UPPER
GREAT LAKES.

BY NEXT WEEKEND THE MAIN ISSUE WILL BE INFLUENCE OF DEVELOPING LOW
PRESSURE OVER PLAINS. 12Z ECMWF FARTHER TO THE EAST...WHILE GFS AND
WPC HAND DRAWN PROGS KEEP LOW SHUNTED MORE OVER THE PLAINS AND SFC
RIDGE OVER THE UPR LAKES. CONSENSUS OF MODELS WHICH HAS DOUBLE
WEIGHTING OF THE TYPICALLY BETTER PERFORMING ECMWF SHOWS INCREASING
CHANCES OF SHOWERS BY LATER IN THE WEEKEND. TEMPS TO END THE
EXTENDED WILL BE AROUND NORMAL...THOUGH MAY REMAIN SLIGHTLY BELOW
NORMAL ALONG LK SUPERIOR DUE TO PREVAILING NORTHERLY SFC WINDS.
EVEN IF IT DOES END UP BELOW NORMAL...NO SNOW IS IN THE
FORECAST...WHICH IS CERTAINLY WELCOME NEWS FOR THOSE WEARY OF THE
WINTER THAT HAS BEEN RELUCTANT TO END.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN MAY 12 2013

AS A RIDGE AND DRIER AIR MOVES INTO THE REGION FROM THE WEST THIS
AFTERNOON...ANY LINGERING CIGS AT CMX/SAW WILL GIVE WAY TO SCT CLOUDS BY
MID TO LATE AFTERNOON. SO...MVFR CIGS AT KSAW WILL BE LAST TO SCATTER
OUT. CLEAR SKIES WILL THEN PREVAIL THIS EVENING THROUGH MON MORNING.
IT WILL REMAIN BLUSTERY AT CMX/SAW THROUGH THIS AFTERNOON WITH NW
GUSTS TO AROUND 30 MPH.

&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 549 AM EDT SUN MAY 12 2013

GALES CONTINUE OVER EASTERN SECTIONS INTO THIS AFTN THEN WINDS
DIMINISH BY TONIGHT AS HIGH PRESSURE RIDGE MOVES ACROSS. WINDS
INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR ON
WED. WARM FRONT SLIDING ACROSS LK SUPERIOR TUESDAY NIGHT AHEAD OF
THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS AGAIN LATE IN THE WEEK.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.

  GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>245-264-
     265.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA