Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 302108
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
408 PM EST FRI JAN 30 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 406 PM EST FRI JAN 30 2015

WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
HUDSON BAY INTO THE NE CONUS RESULTING IN NW FLOW THROUGH THE NRN
GREAT LAKES. AN UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER SRN
MANITOBA. THE SHRTWV AND ASSOCIATED WAA PATTERN SUPPORTED SOME LIGHT
SNOW FROM FAR NRN MN INTO NW ONTARIO WITH VSBY INTO THE 1-3SM RANGE.
AT THE SFC...A RIDGE EXTENDED FROM THE MID MS VALLEY INTO THE WRN
GREAT LAKES. BACKING WINDS TO SW OVER WRN LAKE SUPERIOR AND W OVER
THE ERN LAKE HAVE PUSHED THE LES BANDS OFFSHORE EXCEPT FOR SOME
LINGERING FLURRIES NEAR GRAND MARAIS.

TONIGHT...EXPECT MID/HIGH CLOUDS TO THICKEN INTO THIS EVENING AS THE
AS THE SHRTWV APPROACHES. UPSTREAM TRENDS AND MODELS FCST 285K-290K
ISENTROPIC LIFT...SUGGESTS THAT THE AREA OF LIGHT SNOW WILL SPREAD
THROUGH UPPER MICHIGAN BTWN 03Z-09Z. WITH LITTLE MOISTURE AVAILABLE
AND DRY LOW LEVELS DELAYING THE ONSET OF THE PCPN...QPF OF 0.05 OR
LOWER WITH SLR VALUES NEAR 20/1 WOULD ONLY RESULT IN SNOW AMOUNTS OF
AN INCH OR LESS. HOWEVER...AS LOW LEVEL CONV INCREASES ALONG THE SFC
FRONT/TROUGH AND 850 MB TEMPS DROP TO AROUND -12C...THERE MAY BE A
BRIEF PERIOD OF LAKE ENHANCED SNOW INTO NW UPPER MI THAT MAY BRING
TOTALS INTO THE 1 TO 2 INCH RANGE.

SAT...THE AREA OF LOW LEVEL CONV WITH THE FRONT WILL SLIDE THROUGH
THE REST OF THE NRN CWA WITH THE POTENTIAL FOR A NARROW BAND OF
MODERATE SNOW. ALTHOUGH 850 MB TEMPS DROP TO NEAR -20C BY 00Z
SUN...A QUICK TRANSITION TO A MORE DIFFLUENT/ANTICYCLONIC LOW-LVL
NORTHERLY FLOW AND FALLING INVERSIONS AT OR BELOW 4KFT WILL LIMIT
LES INTENSITY THE REST OF THE DAY. SNOW ACCUMULATIONS OF ONLY AROUND
AN INCH ARE EXPECTED. AFTER MIDDAY HIGHS RANGING FROM THE TEENS NW
TO MID TO UPPER 20S SCNTRL...TEMPS WILL DURING THE AFTERNOON AS
BRISK N TO NW WINDS USHER ARCTIC AIR MASS INTO THE AREA. GUSTY WINDS
WILL ALSO CREATE BLSN IN OPEN AREAS NEAR LAKE SUPERIOR.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 453 AM EST FRI JAN 30 2015

A COLD PATTERN IS SETTING IN FOR THE LONG TERM PORTION OF THE FCST
FEATURING A W COAST RIDGE AND CNTL/ERN TROF. THE RESULTING NW FLOW
INTO THE GREAT LAKES WILL RESULT IN A STEADY FEED OF CANADIAN AIR.
WHILE IT WILL BE COLD WITH TEMPS BLO TO MUCH BLO NORMAL AT
TIMES...TEMPS WILL NOT BE UNUSUALLY COLD FOR THIS TIME OF YEAR. AS
FOR PCPN...THIS IS TYPICALLY A DRY PATTERN FOR THE UPPER LAKES WITH
LITTLE IN THE WAY OF SYNOPTIC PCPN EXPECTED. THE COLD WILL HOWEVER
LEAD TO PERSISTENT LES OFF LAKE SUPERIOR. MOST THE LES WILL BE ON
THE LIGHT SIDE...BUT THERE MAY BE THE OCCASIONAL BOOST WITH THE
PASSAGE OF SHORTWAVES PROVIDING SOME ENHANCEMENT.

BEGINNING SAT...STRONG SHORTWAVE DRIVING SE THROUGH ONTARIO WILL
PUSH A SFC COLD FRONT ACROSS THE AREA AS WINDS SHIFT NRLY BEHIND THE
FRONT SAT MORNING. THERE COULD BE THE TYPICAL QUICK BURST OF MDT TO
POSSIBLY HVY LAKE ENHANCED SNOW ACCOMPANYING COLD FRONT ONSHORE OVER
MAINLY THE ERN HALF OF THE FCST AREA. ALTHOUGH 850MB TEMPS FALL TO
-20 TO -25C BY 00Z SUN...SHARP TRANSITION TO A MORE
DIFFLUENT/ANTICYCLONIC LOW-LVL NORTHERLY FLOW AND A FALLING
INVERSION TO 4KFT OR LOWER WILL LIMIT LES INTENSITY AFTER THE BURST
OF HEAVIER SNOW ASSOCIATED WITH COLD FROPA. SNOW ACCUMULATIONS SAT
SHOULD BE IN THE 1-2 TO POSSIBLY 3 INCH RANGE. AFTER EARLY HIGHS
RANGING FROM THE TEENS NW TO MID TO UPPER 20S SCNTRL...TEMPS WILL
FALL THRU THE DAY AS BRISK N TO NW WINDS USHER ARCTIC AIR MASS INTO
THE AREA. GUSTY WINDS WILL ALSO CREATE BLSN IN OPEN AREAS NEAR LAKE
SUPERIOR.

SAT NIGHT THRU SUN NIGHT...UPPER MI WILL BE DOMINATED BY ARCTIC AIR
MASS WITH INITIAL NORTHERLY LOW-LEVEL FLOW BACKING WNW BY SUN NIGHT.
INVERSION HGTS PLUNGING BLO 2KFT ESPECIALLY LATE SAT NIGHT INTO
SUNDAY COMBINED WITH LOSS OF DGZ DUE TO THE COLD AIR MASS WILL KEEP
LAKE EFFECT SNOW ACCUMULATIONS ON THE LIGHT SIDE...GENERALLY 1-2
INCHES TO PERHAPS LOCALLY 3 INCHES PER 12HRS. THERE COULD BE A
POTENTIAL FOR A LAND BREEZE TO PUSH OUT OVER LAKE SUPERIOR FROM
AROUND MUNISING EASTWARD LATE SAT NIGHT/SUN MORNING AS PRES
GRADIENT/WINDS SLACKEN. IF THIS HAPPENS...A MESOLOW COULD SPIN UP
OVER SCNTRL LAKE SUPERIOR AND LEAD TO HEAVIER SNOW NEAR THE SHORE
BTWN MARQUETTE AND MUNISING...DEPENDING ON THE CIRCULATION
STRUCTURE. SAT NIGHT COULD BE PARTICULARLY CHILLY OVER THE FAR ERN
CWA IF CLOUDS/LES SHIFT W FROM WINDS BECOMING EASTERLY DUE TO
DRAINAGE OF COLD AIR INTO THAT AREA OFF ONTARIO.

MON...LES WILL BEGIN TO SHIFT OUT OVER LAKE SUPERIOR AS WINDS BACK
DUE TO HIGH PRES SHIFTING FROM THE MID MISSISSIPPI VALLEY TO THE
OHIO VALLEY. BY MON AFTN...LES MAY ONLY BE AFFECTING THE KEWEENAW.

TUE-THU...MEDIUM RANGE GUIDANCE IS TRENDING STRONGER WITH THE NEXT
SHORTWAVE DIVING SE OUT OF CANADA FOR THE MIDDLE OF THE WEEK. LOOKS
LIKE THERE MAY BE THE POTENTIAL FOR WIDESPREAD -SN ACROSS THE FCST
AREA TUE/TUE NIGHT ASSOC WITH THE SHORTWAVE ALONG WITH A PERIOD OF
MORE SIGNIFICANT LAKE ENHANCEMENT NEAR LAKE SUPERIOR. BEHIND THE
SHORTWAVE...MODELS INDICATE A VERY COLD SURGE OF ARCTIC AIR WITH
850MB TEMPS OF -25 TO -30C MOVING OVER THE AREA WED INTO EARLY THU.
WITH DGZ DRIVEN BELOW LAKE SURFACE AND INVERSIONS AT OR BLO 5KFT
SETTING UP BEHIND SHORTWAVE...LES ACCUMULATIONS SHOULD BE LIGHT WED
INTO THU. ALTHOUGH ACCUMULATION SHOULD BE LIGHT...THE VERY COLD AIR
AIRMASS WILL RESULT IN SMALL SNOWFLAKES THAT ARE VERY EFFECTIVE AT
REDUCING VISIBILITY. LOWEST TEMPS OF THE WEEK SHOULD OCCUR WED/THU.

MODELS SUGGEST TEMPS SHOULD MODERATE BY LATE NEXT WEEK (FRI-SAT) AS
AMPLIFIED WRN RDG/ERN TROF PATTERN BEGINS TO BREAK DOWN.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1249 PM EST FRI JAN 30 2015

WITH OFFSHORE WINDS...VFR CONDITIONS ARE EXPECTED AT IWD/SAW INTO
THIS EVENING. HOWEVER....LAKE EFFECT CLOUDS AND SNOW SHOWERS WILL
LINGER AT CMX THIS LATE AFTERNOON UNTIL WINDS BACK TO THE SW AND
INCREASE. A PERIOD OF IFR/MVFR VSBY WILL GIVE WAY TO VFR VSBY EVEN
AS THE MVFR CIGS PERSIST. A TROUGH OF LOW PRESSURE NEARING FROM THE W
THAT WILL BRING HIGH CLOUDS ACROSS THE REGION THIS AFTERNOON. THE
TROUGH OVER NW MN AT 00Z/SAT WILL AND CROSS CENTRAL LAKE SUPERIOR BY
12Z. LOOK FOR -SN TO MOVE IN DURING THE EVENING HOURS...AND PICK UP
IN INTENSITY ALONG AND BEHIND THE FRONT. LES AND GUSTY WINDS
PRODUCING BLSN AND LOWER VSBY IS EXPECTED AT CMX BY MID MORNING.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EST FRI JAN 30 2015

GALES CONTINUE TO DIMINISH...AND HEAVY FREEZING SPRAY WILL COME TO
AN END OVER THE E HALF OF LAKE SUPERIOR BY 15Z TODAY AS LIGHTER
WINDS TAKE HOLD AS HIGH PRESSURE BUILDS INTO THE AREA. THE MAIN HIGH
PRESSURE SYSTEM STRETCHING FROM JUST NW OF LAKE SUPERIOR THROUGH E
MN AND W WI WILL SINK TO THE OH VALLEY TODAY...WHILE EXTENDING A
RIDGE ACROSS LAKE SUPERIOR. LOOK FOR A TROUGH ACROSS THE DAKOTAS
THIS AFTERNOON TO SHIFT ACROSS LAKE SUPERIOR TONIGHT...AND EXIT INTO
SE ONTARIO SATURDAY AFTERNOON. LARGE HIGH PRESSURE ACROSS W AND
CENTRAL CANADA SATURDAY WILL SETTLE ACROSS THE N AND CENTRAL PLAINS
STATES SUNDAY INTO SUNDAY NIGHT. NW GALES OF 35 TO NEAR 40KTS WILL
BE POSSIBLE SATURDAY AFTERNOON...ALONG WITH THE RETURN OF HEAVY
FREEZING SPRAY. LOOK FOR A GALE WATCH TO BE HOISTED LATER THIS
MORNING. EXPECT A RIDGE EXTENDING FROM THIS HIGH ACROSS LAKE
SUPERIOR SUNDAY MORNING TO SLOWLY WEAKEN MONDAY AFTERNOON AS THE
AREA OF HIGH PRESSURE DRIFTS ACROSS THE OH VALLEY...AND THEN THE MID
ATLANTIC STATES ON TUESDAY. A TROUGH WILL THEN CROSS THE UPPER GREAT
LAKES ON TUESDAY. LOOKING FARTHER OUT...HEAVY FREEZING SPRAY WILL
LIKELY RETURN ON WEDNESDAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  HEAVY FREEZING SPRAY WARNING FROM NOON SATURDAY TO 5 AM EST
     SUNDAY FOR LSZ264-266-267.

  GALE WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR
     LSZ264-266-267.

LAKE MICHIGAN...
NONE.
&&

$$

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



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