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000
FXUS63 KMQT 140042
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
742 PM EST FRI DEC 13 2013

.UPDATE...
ISSUED AT 742 PM EST FRI DEC 13 2013

SO FAR...LK EFFECT SHSN IMPACTING NCNTRL UPR MI REMAIN DISORGANIZED
AND LGT DESPITE MORE THAN SUFFICIENT OVERWATER INSTABILITY WITH H85
TEMPS AS LO AS -20 OR -21C. THE MAIN INHIBITING FACTOR APPEARS TO BE
LO INVRN NEAR H925 AS SHOWN ON THE 00Z GRB RAOB AND AS DIAGNOSED FM
THE MQT 88D VWP AS WELL AS LGT...ACYC FLOW UNDER SFC RDG AXIS
EXTENDING SEWD OVER LK SUP FM HI CENTER OVER MANITOBA. OTHER
NEGATIVES INCLUDE VERY DRY NATURE OF THE LARGER SCALE AIRMASS
FLOWING OVER LK SUP. ONLY A WEAK LAND BREEZE COMPONENT HAS DVLPD AS
WELL...LIMITING THE LLVL CNVGC THAT MIGHT OTRW INTENSIFY THE LES
NEAR THE SHORE. SO OPTED TO CUT FCST SN AMNTS NEAR LK SUP...AT LEAST
IN THE 00Z-06Z PERIOD. AS THE LLVL FLOW VEERS MORE TOWARD THE E THRU
THE NGT...THE SHSN SHOULD SHIFT FM ALGER/MQT COUNTIES TOWARD THE
KEWEENAW. ARRIVAL OF SOME DEEP LYR QVECTOR CNVGC AS SHOWN BY THE
BULK OF THE NUMERICAL MODELS AFT 06Z MIGHT RESULT IN A HIER INVRN
BASE AND SHSN INTENSIFICATION.

FOR THE SCNTRL...THE 00Z GRB RAOB WAS RELATIVELY MOIST THRU THE
DEPTH OF THE TROP. GIVEN FCST ARRIVAL OF SOME DEEP LYR QVECTOR CNVGC
FM THE W LATER AND THIS DEEPER MSTR IN THE PRESENCE OF THE LLVL WIND
VEERING TOWARD THE E...WL NOT CHANGE GOING LES ADVY FOR MENOMINEE
AND DELTA COUNTIES.
&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 418 PM EST FRI DEC 13 2013

UPPER AIR PATTERN FEATURES TROUGHING OVER EASTERN CANADA INTO GREAT
LAKES WITH THE CLOSEST RIDGING OFFSHORE OF THE WESTERN CONUS. TROUGH
WILL ONLY GET REAMPLIFIED THIS WEEKEND AS TROUGH OVER THE NORTHWEST
TERRITORIES AND NUNAVUT IN NORTHERN CANADA DIGS ACROSS ONTARIO AND
THE GREAT LAKES. SHORTWAVE AHEAD OF THAT TROUGH CURRENTLY OVER
MONTANA AND IDAHO ARRIVES OVER WESTERN UPR MICHIGAN ON SATURDAY
WHILE AT THE SAME TIME STRONG SOUTHERN STREAM WAVE CURRENTLY
CROSSING THE SOUTHERN PLAINS LIFTS ACROSS THE OHIO VALLEY. BOTH
SHORTWAVES WILL AFFECT THE AREA WITH SUBTLE MID-LEVEL MOISTURE AND
LIFT LATE TONIGHT INTO SATURDAY. ON ITS OWN THE FORCING FROM THESE
TWO SHORTWAVES LOOKS MARGINAL FOR MUCH MORE THAN LGT SNOW AMOUNTS
LESS THAN AN INCH OVER CWA. SOUNDINGS INDICATE DRY AIR SEEN ON
12Z SOUNDING FM KINL AT 950-750MB WILL LINGER ACROSS THE CWA INTO
SATURDAY MORNING CNTRL AND EVEN INTO MUCH OF SAT AFTN IN THE
EASTERN CWA...FURTHER DAMPENING AFFECTS FROM THE LARGER SCALE
SYSTEMS.

LK EFFECT FORECAST THROUGH THIS EVENING IS TRICKY AS WINDS ARE LIGHT
AHEAD OF RIDGING EXTENDING ESE OUT OF CNTRL CANADA AND TO THE NORTH
OF LOW PRESSURE ASSOCIATED WITH SOUTHERN STREAM WAVE. LK EFFECT MOST
OF TODAY NEAR LK SUPERIOR HAS REMAIN DISORGANIZED DUE TO DIRECTIONAL
SHEAR IN LK EFFECT CONVECTIVE LAYER WITH NE WINDS AT H85...NNW WINDS
AT 925MB...AND NW WINDS AT THE SFC. LATER THIS AFTN...FLOW OFF THE
SFC BECOMES MORE NRLY AND MAYBE A BIT MORE UNIDIRECTIONAL...BUT SFC
WINDS BEGIN TO BECOME MORE ESE-SE OFF LAND DUE TO LAND BREEZES
SETTING UP. SEEMS LIKE IF WINDS JUST OFF SFC BECOME MORE UNIFORM
AS FCST...THERE WILL BE INCREASED LIKLIHOOD OF MESOLOW IMPACTING
SHORELINES OF EASTERN MARQUETTE AND WESTERN ALGER COUNTIES THIS
EVENING. LATER TONIGHT...WINDS GENERALLY TURN MORE S/SE WHICH WILL
ADVECT THIS AREA OF STRONGER SFC CONVERGENCE AND ASSOCIATED HEAVY LK
EFFECT SNOW BANDS TOWARD THE KEWEENAW. POTENTIAL FOR HEAVIER SNOW
SEEMS BRIEF IN ANY AREA...FOCUSED 23Z-03Z FOR WESTERN ALGER AND
MARQUETTE COUNTY...03Z-07Z FOR BARAGA COUNTY...AND IN THE 08Z-13Z
TIME FRAME MAINLY FOR AREAS TOWARD THE TIP OF THE KEWEENAW /LAC LA
BELLE TO COPPER HARBOR/. SINCE DURING THESE TIMES THE STRONG
CONVERGENCE WILL BE MORE TRANSIENT AND ALSO SINCE THERE IS LOW
CONFIDENCE ON WHETHER ANY HEAVY SNOW WILL OCCUR AT ALL...WILL NOT BE
ISSUING ANY ADVISORIES ALONG LK SUPERIOR. WILL PUT OUT A SEGMENTED
SPS FOR THESE AREAS HIGHLIGHTING POTENTIAL FOR LOCALLY HEAVY SNOW
SHOWERS ALONG THE LK SUPERIOR SHORELINE. INCREASING SOUTH WINDS WILL
PUSH ANY SNOW SHOWERS OFF THE TIP OF THE KEWEENAW BY MID MORNING.

A BIT MORE CONFIDENT ON SEEING MORE PERSISTENT MODERATE TO HEAVY
LAKE EFFECT SNOW OVER PORTIONS OF SCNTRL UPR MICHIGAN /MENONIMEE AND
DELTA COUNTIES/ AS LARGER SCALE LOW-LEVEL TROUGHING FM THE SOUTHERN
STREAM SYSTEM ALLOWS FOR PERSISTENT EASTERLY SFC-H85 WINDS OFF
NORTHERN LK MICHIGAN. INSTABILITY MORE THAN SUFFICIENT WITH H85
TEMPS -15C TO -17C WHILE WATER TEMPS OVER NORTHERN LK MICHIGAN ARE
LIKELY AROUND +4C. ICE COVER HAS BUILT UP RECENTLY OVER THE BAYS DE
NOC AND OVER FAR SOUTHERN PORTIONS OF THE BAY OF GREEN BAY...BUT
OTHERWISE THERE IS PLENTY OF OPEN WATER OVER NORTHERN PORTIONS OF
THE BAY AND ACROSS NORTHERN LK MICHIGAN. FORECAST SOUNDINGS AT MNM
AND ESC INDICATE INVERSION HEIGHTS ONLY AROUND 5KFT...THOUGH THE
SOUNDING IS MOIST TO AT LEAST 10KFT WITH SOME LARGER SCALE LIFT DUE
TO THE SOUTHERN STREAM SYSTEM. AREA OF SFC-950MB CONVERGENCE RAMPS
UP LATE TONIGHT AND MOVES MORE INTO DELTA COUNTY BY MIDDAY SATURDAY.
CONVERGENCE THEN PERSISTS THROUGH 00Z SUNDAY BEFORE SHIFTING FARTHER
NORTH AND EAST AS WINDS BECOME MORE SOUTHERLY. HAVE POSTED WINTER
WEATHER ADVISORIES FOR MENOMINEE AND DELTA COUNTIES /TOTAL SNOWFALL
AMOUNTS IN THE 3-5 INCH RANGE. ADVYS RUN FROM 10Z SAT THROUGH 02Z
SUN FOR MENOMINEE AND A BIT LATER FOR DELTA...14Z SAT THROUGH 06Z
SUN.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 418 PM EST FRI DEC 13 2013

SATURDAY NIGHT INTO SUNDAY NIGHT...
A MID/UPPER LEVEL LOW OVER NW ONTARIO IS EXPECTED TO SLIDE TO THE SE
INTO WRN QUEBEC BY 00Z/MON. THE SFC INVERTED TROUGH FROM NRN LAKE MI
INTO CNTRL UPPER MI AND WRN LAKE SUPERIOR WILL ALSO GRADUALLY MOVE
OFF TO THE EAST.

THE ONGOING LAKE ENHANCED SNOW OFF OF LAKE MI IS EXPECTED TO SHIFT
FROM DELTA COUNTY INTO SRN SCHOOLCRAFT COUNTY FROM 06Z-12Z/SUN. AN
ADVISORY MAY ALSO BE NEEDED IN THIS AREA IF GUIDANCE CONTINUES TO
SUGGEST THAT THE ONSHORE SRLY FLOW WILL PUSH THE SNOW INLAND.
OTHERWISE MORE WIDESPREAD LIGHT SNOW OF AN INCH OR LESS WILL SPREAD
THROUGH MOST OF THE CWA EVEN AS THE STRONGER 700-300 MB QVECTOR CONV
WITH THE MID LEVEL REMAINS TO THE NORTH.

LES WILL ALSO INCREASE INTO WRN UPPER MI AS A COLD FRONT/TROUGH
MOVES IN AND WINDS VEER SHARPLY TO THE NNW. A BRIEF PERIOD OF
MODERATE TO HEAVY SNOW MAY DEVELOP WITH THIS FEATURE WITH SNOWFALL
AMOUNTS OF 2 TO 5 INCHES POSSIBLE BY 18Z/SUN.

THE HIGHER RES MODELS HAVE BEEN CONSISTENT IN DEVELOPING A CLOSED
CIRCULATION OR MESO LOW OVER CNTRL LAKE SUPERIOR THAT WILL GRADUALLY
WOBBLE FROM N CNTRL LAKE SUPERIOR INTO THE SE PORTION OF THE LAKE
SUN AFTERNOON AND INTO ERN UPPER MI BY SUNDAY EVENING. AN AREA OF
HEAVIER LES IS LIKELY TO DEVELOP WITH THE STRONG LOW LEVEL CONV ON
THE BACK SIDE OF THE LOW. THERE IS SOME UNCERTAINTY ON THE WITH THE
POSITION AND TIMING OF THIS FEATURE THAT MAY AFFECT N CNTRL UPPER MI
BY LATE AFTERNOON OR EARLY EVENING AND BRING SEVERAL INCHES OF
SNOW IN A FEW HOURS.

MON...AN AREA OF WAA/ISENTROPIC LIFT DEVELOPING AHEAD OF THE NEXT
CLIPPER SHRTWV MOVING THROUGH NRN ONTARIO MAY BRING SOME LIGHT SNOW
ACROSS THE REGION. WITH LIMITED MOISTURE INFLOW AND ONLY A BRIEF
PERIOD OF THE STRONGER UPWARD MOTION...ANY ACCUMULATIONS SHOULD BE
LIGHT...GENERALLY AROUND AN INCH.

TUE-WED...ANOTHER WEAK SHRTWV MAY PIVOT THROUGH THE AREA TUE
BRINGING CONTINUED CHANCES FOR SOME LIGHT SNOW AND LAKE ENHANCED
SNOW FOR W WIND SNOWBELTS. BUT COLDER AIR MOVING IN BEHIND THE SHRTWV
AND SFC TROUGH WILL DROP 850 MB TEMPS TO AROUND -17C TO -20C BY WED
MORNING BRINGING ANOTHER ROUND OF LES TO LOCATIONS FAVORED BY WNW
WINDS.

THU-FRI...A SHRTWV DIGGING INTO THE WRN CONUS WILL RESULT IN A POSITIVE
TILT TROUGH WITH WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE
06Z/12Z/13 GFS AND 00Z/13 ECMWF SUGGESTED THAT A SFC LOW DEVELOPING
OVER THE PLAINS COULD MOVE INTO UPPER MI BRINGING WIDESPREAD PCPN
AND COULD DRAG ENOUGH WARM AIR TO THE NORTH FOR SOME MIXED PCPN.
HOWEVER...GIVEN THE LACK OF CONTINUITY WITH THIS TREND OVER THE LAST
SEVERAL DAYS AND THE TREND WITH 12Z/13 ECMWF AND ENSEMBLE MEANS WHICH
SHOWS A MORE SUPPRESSED SFC LOW TRACK...NO MENTION OF MIXED PCPN WAS
ADDED AT THIS TIME.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 637 PM EST FRI DEC 13 2013

CMX...ALTHOUGH THERE MAY BE SOME SCT LGT -SHSN ARND THIS EVNG...A
GENERALLY DRY NE WIND ON THE SRN FLANK OF HI PRES MOVING THRU
ONTARIO SHOULD RESULT IN PREDOMINANT VFR CONDITIONS UNTIL ARND
09Z...WHEN THE VEERING LLVL WINDS SHIFT TO THE E AND POSSIBLY ALLOW
MORE -SHSN/MVFR CONDITIONS TO IMPACT THIS LOCATION. AS THE FLOW
CONTINUES TO VEER TO THE SE AND THEN S...ANY LES SHOULD SHIFT TO THE
N OF CMX. THERE MAY BE SOME -SN AS A DISTURBANCE APRCHS FM THE NW...
BUT DOWNSLOPE FLOW SHOULD RESULT IN VFR CONDITIONS.

IWD...WITH DRY AND DOWNSLOPE E WIND VEERING TO THE S THRU THIS
PERIOD...VFR CONDITIONS SHOULD DOMINATE. SOME -SN MAY DEVELOP ON
SAT...BUT DOWNSLOPE NATURE OF THE PREVAILING FLOW SHOULD KEEP THE
LLVLS DRY ENUF FOR VFR CIGS/VSBYS.

SAW...AS THE LLVL FLOW VEERS TOWARD THE NE THIS EVNG...LES BANDS
JUST TO THE E OF THIS SITE SHOULD SHIFT OVER SAW FOR A COUPLE OF
HRS...POSSIBLY LOWERING CIGS/VSBYS INTO THE MVFR RANGE. BUT AS THE
FLOW CONTINUES TO VEER TOWARD A DRIER E DIRECTION...THE SHSN SHIFT
TO THE NW OF THIS SITE AND RESULT IN A PERIOD OF VFR WX THRU SAT
MRNG. SOME -SN IS LIKELY TO DVLP ON SAT AFTN...AND SSE FLOW
UPSLOPING OFF LK MI WL BRING ABOUT MVFR CONDITIONS.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 418 PM EST FRI DEC 13 2013

NORTHEAST WINDS LESS THAN 20 KNOTS BECOME SOUTHEAST THROUGH SATURDAY
AS A RIDGE OVER SOUTH CENTRAL CANADA BUILDS TOWARD THE UPPER GREAT
LAKES AND A LOW PRESSURE SYSTEM PASSES TO THE SOUTH ACROSS THE LOWER
GREAT LAKES. A TROUGH WILL THEN CROSS LAKE SUPERIOR LATE SATURDAY
NIGHT INTO SUNDAY BRINGING A QUICK ROUND OF 20 TO 30 KNOTS NW-N
WINDS. ANOTHER RIDGE BUILDS IN FOR MONDAY BEFORE THE PASSAGE OF LOW
PRESSURE TRACKING ACROSS SOUTH-CENTRAL CANADA RESULTS IN NW GALES TO
35 KNOTS TUESDAY AFTERNOON INTO TUESDAY EVEING FOR ALL OF LAKE
SUPERIOR.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW ADVISORY FROM 9 AM SATURDAY TO 1 AM EST SUNDAY
     FOR MIZ013.

  LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 8 PM CST SATURDAY FOR
     MIZ012.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

UPDATE...KC
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...KC
MARINE...JLA