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000
FXUS63 KMQT 110527
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1227 AM EST WED DEC 11 2013

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 447 PM EST TUE DEC 10 2013

MAIN FCST CONCERN IN THE SHORT TERM REVOLVES AROUND LES TRENDS AS
REINFORCING ARCTIC AIR MASS PASSES ACROSS THE AREA.

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN EXPANSIVE POLAR VORTEX
CENTERED OVER HUDSON BAY. WITHIN THE CIRCULATION...ONE SHORTWAVE HAS
MOVED E OF UPPER MI/LAKE SUPERIOR. WAVE BROUGHT A PERIOD OF -SN WITH
VERY LITTLE ACCUMULATION ACROSS MAINLY SRN AND ERN UPPER MI EARLIER
TODAY. THE SMALL SNOWFLAKES WERE EXCELLENT VIS RESTRICTORS.
UPSTREAM...ANOTHER SHORTWAVE WAS SWINGING THRU SRN MANITOBA/ND/NRN
MN. TYPICAL FOR ARCTIC AIR MASSES...IN THE WAKE OF THE FIRST
SHORTWAVE...SKIES GENERALLY CLEARED OUT AWAY FROM LAKE EFFECT AREAS.
PER VIS SATELLITE IMAGERY...SFC TROF/WIND SHIFT ACROSS LAKE SUPERIOR
HAS LEAD TO A BAND OF HVY LES THAT HAS SETTLED S ACROSS THE KEWEENAW
TODAY. BAND IS A LITTLE MORE DISORGANIZED NOW...AND EXTENDS E ACROSS
ERN LAKE SUPERIOR PER SATELLITE/KMQT RADAR IMAGERY.

AS NEXT SHORTWAVE MOVES ACROSS THE AREA TONIGHT...MODELS ARE NOT
INDICATING MUCH IN THE WAY OF FORCING PER QVECTORS...PROBABLY DUE TO
CAA AT LOW-LEVELS. NONETHELESS...CONDITIONS ARE FAVORABLE FOR
MDT/HVY LES AS INVERSIONS ARE UP AROUND 8KFT. NEGATIVE FACTOR WILL
BE THE COLD AIR SUPPRESSING THE DGZ...MAINLY OVER THE W WHERE
SHORTER FETCH LEADS TO LESS LAKE MODERATION/WARMING OF THE
LOW-LEVELS. HAVE SOME CONCERN THAT SNOWFLAKES MAY END UP QUITE
SMALL...KEEPING ACCCUMULATIONS LOWER THAN FCST. ON THE OTHER
HAND...THE SMALL SNOWFLAKES CREATE MORE OF A DRIVING HAZARD DUE TO
THEIR EFFECTIVENESS AT REDUCING VIS. IN ANY EVENT...ADVYS REMAIN
UP FOR THE WRN COUNTIES. HEAVIEST SNOW SHOULD FOCUS ACROSS NRN
ONTANAGON COUNTY INTO CNTRL HOUGHTON COUNTY...WHERE LOW-LEVEL
CONVERGENCE WILL BE ESPECIALLY STRONG THRU THE EVENING.

OVER THE E...NOT ONLY DOES A LONGER FETCH AND HIGHER DGZ POINT
TOWARD MORE SIGNIFICANT ACCUMULATIONS...BUT THERE ARE INDICATIONS
FROM ALL HIGH RES MODEL GUIDANCE FOR ONE OR TWO AREAS OF STRONGLY
FOCUSED CONVERGENCE OWING TO LAND BREEZES OFF ONTARIO AND NCNTRL
UPPER MI. EXACTLY WHERE THE CONVERGENCE ZONES SET UP AND WHETHER
THEY REMAIN STATIONARY OR MEANDER WILL CONTROL HOW MUCH SNOW FALLS.
PERUSAL OF A NUMBER OF HIGH RES MODELS SHOW WATER EQUIVALENT PCPN
TOTALS ANYWHERE FROM 1.5 TO 3.5 INCHES AIMING TOWARD WHITEFISH PT
VCNTY BY WED EVENING. IF SNOW RATIOS END UP AROUND 20 TO 1...YOU END
UP WITH A RIDICULOUS POTENTIAL SNOW ACCUMULATION. HOW THE EXPECTED
BAND OR BANDS SETUP TONIGHT WILL SET THE STAGE FOR WHETHER OR NOT
THE POTENTIAL SNOW ACCUMULATION IS REALIZED SOMEWHERE OVER NE UPPER
MI. OTHERWISE...OVERALL MODEL TREND SUGGESTS A LITTLE MORE NORTHERLY
COMPONENT TO THE WIND...SO ADVY WAS EXPANDED TO NRN SCHOOLCRAFT
COUNTY AND HEAVIER SNOW AMOUNTS WERE SPREAD A LITTLE FARTHER W IN
ALGER COUNTY...THOUGH HEAVIEST SNOW BANDS SHOULD STILL END UP E OF
MUNISING.

ONLY OTHER ITEM OF NOTE TONIGHT WAS INCLUSION OF LOW WIND CHILLS IN
HEADLINE PRODUCTS OVER WRN UPPER MI...INCLUDING WIND CHILL ADVY FOR
IRON COUNTY WHICH WAS NOT UNDER HEADLINE INVOLVING SNOW.

ON WED...LES WILL TREND LIGHTER OVER THE W AS INVERSIONS FALL A BIT.
LES SHOULD REMAIN QUITE HEAVY OVER THE E...ESPECIALLY DURING THE
MORNING WHEN CONVERGENCE REMAINS STRONG.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 410 PM EST TUE DEC 10 2013

LOOK FOR A SERIES OF SYSTEMS TO SLIDE IN ON THE NW FLOW
ALOFT...KEEPING SNOW IN THE FCST FOR MUCH OF THE PERIOD. IT WILL BE
A PERIOD OF ALMOST CONTINUOUS SFC TROUGHS OVER CENTRAL AND EASTERN
UPPER MI. THE BUFKIT TIME HEIGHT/OVERVIEW DATA FROM THE GFS AT CMX
LOOKS IMPRESSIVE. ALTHOUGH SNOW AMOUNTS ARE RELATIVELY
MINIMAL...THERE IS NEARLY CONSTANT SNOW FCST THROUGH 06Z MONDAY.

THE PERSISTENT 500MB TROUGH OVER EASTERN CANADA AND THE EAST HALF OF
THE UNITED STATES WILL STILL BE IN PLACE WEDNESDAY NIGHT. EVEN OVER
THE W HALF OF THE NATION THE SIZABLE RIDGE EXTENDING UP THROUGH THE
CASCADES WILL BE UNDERMINED BY CLOSED LOW SPINNING ACROSS S CA
WEDNESDAY NIGHT THROUGH THURSDAY. EXPECT NW FLOW ALOFT THROUGH THE
END OF THE WORK WEEK. THE MODELS SPREAD FOR TEMPERATURES FRIDAY
AFTERNOON ARE ALL OVER THE PLACE...RANGING FROM AROUND 6 TO 23 NEAR
THE WI BORDER. WENT WITH A MIDDLE OF THE ROAD FCST FOR NOW WITH
HIGHS IN THE TEENS CWA WIDE...AND WILL FINE-TUNE IT AS THE TIME
NEARS.

BY 00Z SATURDAY THE MAIN LOW WILL HAVE MOVED FROM HUDSON BAY TO
CENTRAL QUEBEC...SLOWLY MARKING THE END TO ITS DOMINANCE. WHILE SOME
IMPROVEMENT IN THE FRIGGED TEMPERATURES OF LATE FRIDAY INTO
SATURDAY...WE WILL STILL END UP WELL BELOW THE NORMAL HIGH TEMPS FOR
THIS TIME OF YEAR...WHICH MAY TYPICALLY RISE INTO THE MID TO UPPER
20S.

THE NEXT QUICK MOVING WAVE IN THE 500MB NW FLOW OVER N SASKATCHEWAN
AND MANITOBA AT 06Z SATURDAY WILL PUSH ACROSS THE UPPER GREAT LAKES
LATE SATURDAY NIGHT THROUGH SUNDAY.

EXPECT BRIEF RIDGING ALOFT SUNDAY NIGHT INTO MONDAY TO BECOME
SUPPRESSED AHEAD OF THE NEXT TROUGH NEARING FROM THE NORTHWEST. THE
BEST CHANCE FOR SHORT LIVED CWA-WIDE HIGH PRESSURE AT THE SFC WILL
BE SUNDAY NIGHT. THIS WILL BE THE ONLY PERIOD WITH SLIGHT CHANCE
POPS OR LESS ACROSS THE AREA. THE TROUGH TO THE NORTHWEST WILL
LIKELY SWING ACROSS THE UPPER GREAT LAKES MONDAY...AND LINGER
THROUGH TUESDAY...AS LES PICKS UP AGAIN ACROSS THE KEWEENAW
PENINSULA. THE GFS AND ECMWF HAD VERY SIMILAR TIMING ON THE SFC
LOW...SET UP ACROSS CENTRAL LAKE SUPERIOR AND EASTERN ONTARIO AT 18Z
TUESDAY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1225 AM EST WED DEC 11 2013

KIWD...EXPECT MVFR CONDITIONS TO LAST THROUGH WED EVENING WITH LAKE
EFFECT SNOW SHOWERS CONTINUING. AS WINDS BECOME MORE SW BY WED
EVENING...LAKE CLOUDS WILL PUSH NORTH AND CONDITIONS WILL BE VFR.

KCMX...EXPECT IFR TO LIFR CONDITIONS THROUGH THE FORECAST PERIOD
WITH LAKE EFFECT SNOW BANDS PASSING THROUGH. WITH GUSTY WINDS...THE
BLOWING SNOW WILL BE THE MAIN FACTOR IN THE LOWER VISIBILITIES.

KSAW...VFR CONDITIONS WILL CONTINUE THRU THE FORECAST PERIOD.
DOWNSLOPE NATURE OF THE W WIND AND RELATIVE DRYNESS OF THE AIRMASS
SHOULD MAINTAIN THE VFR WX AT THIS SITE EVEN IF SOME FLURRIES MAKE
IT INTO THE AREA WED MORNING.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EST TUE DEC 10 2013

FREEZING SPRAY AND GALES TO 35-40KTS WILL BE THE MAIN
CONCERNS...COMING TO AN END WEDNESDAY NIGHT. HIGH PRESSURE OVER W
CANADA WILL DRIFT SE THROUGH THURSDAY NIGHT. EXPECT A TROUGH TO
LINGER OVER THE UPPER GREAT LAKES DURING THE SAME TIME PERIOD.
ANOTHER HIGH CENTERED OVER CENTRAL CANADA WILL THEN SLIDE ACROSS
ONTARIO ON FRIDAY...AND INTO QUEBEC ON SATURDAY. ALSO FRIDAY INTO
SATURDAY...A LOW WILL ORGANIZE ACROSS THE MID MISSISSIPPI VALLEY.
THE LOW WILL SHIFT INTO THE NE STATES SUNDAY...WITH A TROUGH
LINGERING OVER THE UPPER GREAT LAKES...AS HIGH PRESSURE SLIDES
ACROSS MANITOBA.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
     MIZ004-084.

  LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ085.

  LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ002-
     003-006.

  LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001.

  LAKE EFFECT SNOW ADVISORY UNTIL 11 AM CST WEDNESDAY FOR MIZ009.

  LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THURSDAY FOR MIZ007.

  WIND CHILL ADVISORY UNTIL 11 AM CST WEDNESDAY FOR MIZ010.

LAKE SUPERIOR...
  HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST THIS EVENING FOR
     LSZ266.

  HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY
     FOR LSZ162-240>245-248>251-263>265.

LAKE MICHIGAN...
  HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST EARLY THIS MORNING
     FOR LMZ221-248-250.

&&

$$

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