Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 271015
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
515 AM EST THU NOV 27 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 510 PM EST WED NOV 26 2014

WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW AN AMPLIFIED
PATTERN ACROSS NAMERICA WITH A RIDGE ALONG/JUST OFF THE W COAST...A
TROF EXTENDING FROM NCNTRL CANADA TO THE GULF OF MEXICO AND A RIDGE
OVER THE WRN ATLANTIC. A SHORTWAVE TROF SWINGING SE THRU NRN
ONTARIO/NRN MN IS PRODUCING SOME -SN FROM NW WI ACROSS WRN UPPER MI
INTO NRN ONTARIO. AT THE SFC...SHARPENING TROF RUNS FROM NEAR KIWD
TO JUST S OF KCMX AND THEN NE ACROSS ERN LAKE SUPERIOR. MDT TO HVY
LAKE ENHANCED SNOW IS SPREADING INTO WRN UPPER MI IN ASSOCIATION
WITH THE TROF. OFF TO THE NW...STRONG SFC HIGH PRES ACROSS
MANITOBA/SASKATCHEWAN IS BUILDING S AND E INTO THE NRN PLAINS.

PERIOD OF LAKE ENHANCED SNOW IS EXPECTED TONIGHT UNDER HEIGHT
FALLS/DEEP LAYER QVECTOR CONVERGENCE WITH SHORTWAVE SWINGING ACROSS
THE UPPER LAKES. BEST...MOST PERSISTENT LOW-LEVEL CONVERGENCE IS
INDICATED OVER THE FAR W. SO...MOST SUSTAINED MDT TO AT TIMES HVY
SNOW WILL OCCUR OVER THE FAR W FROM THE PORCUPINE MTNS TO KIWD. WITH
DGZ FALLING INTO THE LOW-LEVELS WHERE UPWARD MOTION IS FOCUSED...
EXPECT SNOW TO WATER RATIOS TO INCREASE INTO THE 20-30 TO 1 RANGE
TONIGHT. A LITTLE CONCERNED THAT THE UPWARD MOTION IS ONLY DEPICTED
IN THE LOWEST LEVELS THIS EVENING...SUGGESTING LITTLE OVERALL
SYNOPTIC SUPPORT WITH PASSING SHORTWAVE. THIS MAY TEND TO LIMIT
COVERAGE OF HVY SNOW TO ONLY THE AREAS WHERE LOW-LEVEL CONVERGENCE
IS FOCUSED. AS IT STANDS NOW...SITUATION APPEARS TO BE A MARGINAL
WARNING EVENT WITH WARNING THRESHOLDS ONLY POTENTIALLY BEING MET IN
A FEW LOCALIZED AREAS (8 INCHES OR MORE IN 12HRS OR 12 OR MORE IN
24HRS). LARGE PORTIONS OF ONTONAGON/GOGEBIC COUNTIES WILL PROBABLY
FALL IN THE 4 TO 7 INCH SNOWFALL RANGE. OF NOTE...THERE IS A FAIRLY
CONSISTENT SIGNAL AMONG MOST OF THE HIGH RES MODEL GUIDANCE FOR THE
HEAVIEST SNOW TO AFFECT LOCATIONS JUST W OF KIWD. WILL BE
INTERESTING TO SEE IF THAT INDEED DOES HAPPEN. OVER THE KEWEENAW...
SNOWFALL HAS NOT BEEN ESPECIALLY NOTEWORTHY WITH SFC TROF PASSAGE
WHICH IS WHEN THE HEAVIEST SNOWFALL WOULD LIKELY OCCUR. WITH A
DECENT LOW-LEVEL CONVERGENCE SIGNAL LACKING TONIGHT...CONSIDERED
DROPPING ADVY...BUT WILL HOLD OFF FOR NOW WITH POTENTIAL FOR SNOW TO
STILL PICK UP FOR A TIME THIS EVENING DURING THE PERIOD OF SYNOPTIC
FORCING. TO THE E...LONGER FETCH/BETTER TERRAIN ENHANCEMENT WILL
LEAD TO ANOTHER AREA OF HEAVIER SNOW DEVELOPING OVER NCNTRL UPPER MI
SPREADING FROM BARAGA COUNTY/FAR NRN MARQUETTE COUNTY EARLY THIS
EVENING TO ALGER COUNTY LATE EVENING. LOOKS LIKE SOLID ADVY AMOUNTS
FROM THE HURON MTNS TO NEGAUNEE AND EAST INTO WRN ALGER COUNTY.
POTENTIAL IS THERE FOR LOCALIZED WARNING AMOUNTS GIVEN THE
INCREASING SNOW TO WATER RATIOS AND THE LIKLIHOOD OF A LAKE NIPIGON
INITIATED DOMINANT BAND LATER TONIGHT INTO THE MORNING HRS THAT
WOULD LIKELY IMPACT LOCATIONS SOMEWHERE FROM AROUND BIG
BAY/MARQUETTE TO AROUND THE SHOT POINT AREA. IF SUCH A BAND DOES
DEVELOP AND BECOME STATIONARY FOR SEVERAL HRS...WARNING AMOUNTS MAY
BE ACHIEVED. BLSN WILL ALSO BE AN ISSUE IN THE OPEN AREAS ALONG LAKE
SUPERIOR WHERE WINDS WILL GUST OVER 30 MPH. WHILE THERE MAY BE  A
BRIEF PERIOD OF HEAVIER SNOW OVER LUCE COUNTY WITH TROF PASSAGE...
SETUP AFTER TROF PASSAGE IS NOT FAVORABLE FOR ADVY SNOWFALL AMOUNTS
IN THAT AREA. ACROSS THE REST OF THE AREA...EXPECT SOME -SN FOR A
TIME TONIGHT. SOME OF THE LES OFF LAKE SUPERIOR WILL REACH NRN DELTA
AND SRN SCHOOLCRAFT COUNTIES TO PROVIDE AN INCH OR TWO OF SNOWFALL.

ON THANKSGIVING DAY...FCST SOUNDINGS SHOW INVERSIONS AT A LOW 4KFT
TO START THE DAY. LOW-LEVEL FLOW TRENDS ANTICYCLONIC DURING THE
DAY...ESPECIALLY SO OVER WRN LAKE SUPERIOR AS SFC HIGH PRES RIDGE
WILL EXTEND FROM THE MID MISSISSIPPI VALLEY N THRU WRN UPPER MI/WRN
LAKE SUPERIOR BY 00Z FRI. THESE 2 FACTORS COMBINED WITH RISING
HEIGHTS/LARGE SCALE SUBSIDENCE/QVECTOR DIVERGENCE WILL LIMIT LES
INTENSITY AND WILL RESULT IN LES DIMINISHING FROM W TO E THRU THE
DAY. IN FACT OVER THE FAR W...LES WILL END LATE IN THE AFTN AROUND
KIWD AS FLOW BACKS SW. THE ONE POSTIVE FACTOR FOR THE LES ON
THANKSGIVING DAY IS THAT THE DGZ WILL OCCUPY MOST OF THE CONVECTIVE
LAYER TO FLUFF UP SNOW ACCUMULATIONS. SO...DESPITE THE NEGATIVES
LEADING TO MOSTLY LIGHT LES ON THE WHOLE...MIGHT BE ABLE TO FLUFF UP
3-4 INCHES OF SNOW WHERE LES IS MOST PERSISTENT. THE GREATEST
ACCUMULATIONS WILL OCCUR E OF MARQUETTE WHERE LOW-LEVEL FLOW IS MORE
CYCLONIC THRU THE EARLY PART OF THE DAY AND WHERE LAKE NIPIGON
PRECONDITIONING WILL COME INTO PLAY. AWAY FROM THE MAIN LES...
SCT -SHSN/FLURRIES ARE POSSIBLE AT TIMES...EXCEPT OVER THE FAR
SCNTRL. TEMPS WILL BE UNSEASONABLY COLD ON THANKSGIVING DAY AS 850MB
THERMAL TROF (AROUND -20C) PASSES ACROSS THE AREA. EXPECT HIGHS
MOSTLY IN THE LOW/MID TEENS...TO AROUND 20F ALONG LAKE SUPERIOR AND
E. RECORD LOW MAX TEMP OF 18F HERE AT NWS MQT WILL FALL. IF TEMP
DOESN`T REACH 14F...IT WILL BE THE COLDEST MAX TEMP FOR SO EARLY IN
THE SEASON.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 509 AM EST THU NOV 27 2014

TROUGHING BRINGING THE WELL BLO NORMAL TEMPERATURES ACROSS THE AREA
TODAY EXITS OVER EASTERN CANADA AND NEW ENGLAND ON FRIDAY. UPPER
LEVEL FLOW BECOMES MORE PROGRESSIVE FROM THE PACIFIC NW ACROSS THE
NORTHERN PLAINS AND OVER THE GREAT LAKES REGION. SHORTWAVE TROUGH
CURRENTLY JUST OFFSHORE OF PACIFIC NW HEADS EAST AND WILL SUPPORT
AREA OF WARM ADVECTION/ISENTROPIC ASCENT ALONG TIGHT BAROCLINIC ZONE
SFC-H85. MODELS STILL DIFFER ON WHERE SHARPEST TEMPERATURE GRADIENT
SETS UP...BUT SEEMS THAT AT LEAST THE SOUTH HALF OF UPR MICHIGAN
SEES WIDESPREAD SNOW...WITH A BIT MORE QUESTION ON NORTHERN EXTENT.
IF BAND OF MORE CONCENTRATED SNOW SLIDES NORTHWARD THEN COULD SEE
AMOUNTS NEARING ADVY ALONG THE WI BORDER AND NEAR BAY OF GREEN BAY
FRIDAY AFTN INTO FRIDAY EVENING. PRIMARY AREA OF CONCERN STILL IS OVER
EASTERN CWA THOUGH...SCHOOLCRAFT AND LUCE COUNTIES...DUE TO LAKE
ENHANCEMENT OFF LK MICHIGAN AS THE LARGER SCALE MOISTURE AND FORCING
WITH THE SHORTWAVE COMBINES WITH MEAN BLRY SSW FLOW AND H85 TEMPS
LOWER THAN -10C...PLENTY LOW ENOUGH FOR LAKE ENHANCEMENT WITH LK
MICHIGAN WATER TEMPS AROUND UP TO 4C. IF THE FARTHER NORTH NAM IDEA
IS CORRECT WITH MORE DIRECT INFLUENCE FROM THE INCOMING SYSTEM...THEN
MODERATE TO HEAVY SNOW WOULD OCCUR. BLEND OF OTHER MODELS...INCLUDING
THE FAVORED ECMWF/GEM-NH...POINT TO SOLID ADVY AMOUNTS. WILL MENTION
IN THE HWO AND HIGHLIGHT IN EHWO GRAPHICS...BUT NOT ISSUE ANY WATCH
ATTM GIVEN THE UNCERTAINTY ON TRACK OF INCOMING SYSTEM.

MESSY FORECAST LATER FRIDAY NIGHT INTO SATURDAY. OR MAYBE IT WILL
JUST END UP BENIGN. STILL TRYING TO FIGURE THIS OUT...BUT ECMWF/GEM
AND TREND FROM GFS WOULD SUGGEST MORE DRIER IDEA. ECMWF AND GEM ARE
FARTHER NORTH WITH LARGER SCALE Q-VECTOR CONVERGENCE AND DEEP
MOISTURE TIED INTO THE NEXT SHORTWAVE/SFC LOW MOVING ACROSS IN WHAT
LOOKS MORE LIKE A ZONAL FLOW PATTERN. H85 TEMPS QUITE WARM OFF THE
ECMWF WITH +8C...YES PLUS 8...INTO SCNTRL UPR MICHIGAN BY 00Z
SUNDAY. GEM EVEN WARMER AND THE NAM/GFS IN THE BALLPARK AS WELL.
EVEN WITH THE WARMTH...SOUNDINGS FM THE NAM/GFS SUGGEST THE ONLY
KIND OF PRECIP OCCURRING...IF ANY...WOULD BE DRIZZLE AS ONLY MOISTURE
IS BLO H85 WITH DRY AIR ALOFT. EXCEPTION TO THIS WOULD BE OVER THE
NORTH AND EAST CWA SATURDAY MORNING AND THEN RETURNING TO THE
NORTHWEST CWA LATER SATURDAY NIGHT ONCE THE SFC LOW PASSES BY AND A
COLD FRONT RE-ENTERS THE PICTURE. HAVE TRENDED TOWARD THE DZ/FZDZ
IDEA FOR LATE FRIDAY NIGHT THROUGH SATURDAY. NOW IF THIS FORECAST OF
LOW LEVEL MOISTURE TRAPPED BENEATH THE WARM AIR ADVECTION ALOFT TURNS
OUT TO BE OVERDONE AS HAS OCCURRED IN THE PAST...THEN SATURDAY COULD
ACTUALLY END UP BEING AN NICE DAY WITH PARTLY SUNNY SKIES AND ABOVE
NORMAL TEMPS. MIXING TO H9 VALUES OFF THE GFS WOULD YIELD LOW 40S
OVER PARTS OF THE AREA. FOR NOW...KEPT WITH THE LOW CLOUD/DZ IDEA AND
HAVE HIGHS IN THE MID 30S.

ONCE THE COLD FRONT ARRIVES LATER SATURDAY NIGHT...PRETTY QUICK DROP
OFF IN TEMPS AT H85. ECMWF SLOWER THAN THE GFS AND PROBABLY IS MORE
ON TRACK GIVEN THE FARTHER NORTH TREND OF WARMER AIR TO START THE
WEEKEND. EVEN SO...ENOUGH COLD AIR BY SUNDAY AFTN TO START THE LAKE
EFFECT UP AGAIN FOR AREAS FAVORED BY NORTHWEST WINDS. SHORTWAVE MOVING
THROUGH SUNDAY INTO MONDAY COULD RESULT IN A PERIOD OR TWO OF LAKE
ENHANCEMENT. CORE OF COLDEST AIR ARRIVES ON MONDAY. H85 TEMPS A VERY
CHILLY -20C TO -24C...COLDEST ON THE GFS. AT LEAST LIGHT LES SHOULD
CONTINUE NEAR LK SUPERIOR AND EAST. CENTER OF HIGH PRESSURE RIDGE IS
MORE OVER THE PLAINS...SO PRESSURE GRADIENT WILL BE FAIRLY TIGHT
LEADING TO SOME LOWER WIND CHILLS ON MONDAY MORNING.

ONCE THE HIGH MOVES TOWARD THE LOWER GREAT LAKES ON TUESDAY...TEMPS
MODERATE IN WARM AIR ADVECTION ON THE BACK SIDE OF THE HIGH. COULD
BE SOME SNOW BREAK OUT OVER REGION DUE TO THE WARM AND MOIST ADVECTION.
BEST CHANCE OF THAT LOOKS TO BE NEXT TUESDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 126 AM EST THU NOV 27 2014

WITH INCREASING SUBSIDENCE/DRY ADVECTION IN ADVANCE OF HI PRES
MOVING E FM THE NRN PLAINS...EXPECT GRADUALLY IMPROVING CONDITIONS
AT THE TAF SITES FM IFR IN THE FIRST COUPLE HRS TO PREDOMINANT MVFR.
WITH THE MOST FAVORABLE UPSLOPE/CONFLUENT N WIND...IWD WL SEE A
LONGER PERSISTENCE OF SHSN/IFR VSBYS. AS THE HI AND ACCOMPANYING
DRIER AIR EDGE CLOSER ON THANKSGIVING...THE LLVL WINDS WL BACK
TOWARD THE W BY LATE THIS AFTN AND THEN TO THE WSW THIS EVNG...
RESULTING IN A RETURN TO VFR CONDITIONS IN THE AFTN AT IWD AND SAW.
BUT MORE UPSLOPE WIND AT CMX MAY HOLD CIGS IN THE MVFR RANGE AT THAT
LOCATION THRU THE TAF PERIOD.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 348 PM EST WED NOV 26 2014

A SFC TROUGH WILL SLIDE SOUTH OVER LAKE SUPERIOR TONIGHT.
BEHIND THE TROUGH...EXPECT NORTHERLY WINDS TO 30 KTS. WINDS WILL
THEN DIMINISH TO UNDER 20 KT W TO E THU/THU NIGHT AS HIGH PRES RIDGE
ARRIVES. WITH ANOTHER COLD FRONT PUSHING ACROSS THE UPPER LAKES SAT
NIGHT...EXPECT INCREASING S/SW WINDS TO 15-25KT FRI INTO SAT AHEAD
OF FRONT. BEHIND THE FRONT...NW WINDS MAY REACH 20-30KT LATE SAT
NIGHT AND SUN AND INCREASE TO GALES BY SUN NIGHT INTO MON.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
     MIZ006.

  LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001-
     003-004.

  LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     MIZ005.

  LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ THIS
     AFTERNOON FOR MIZ002-009.

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

$$

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




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