Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 252157
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
457 PM EST TUE NOV 25 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 450 PM EST TUE NOV 25 2014

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN OVER
NAMERICA WITH RIDGING ALONG/JUST OFF THE W COAST...A TROF EXTENDING
FROM N OF HUDSON BAY TO TX AND A RIDGE JUST OFF THE EAST COAST.
SHORTWAVE THAT PROVIDED WIDESPREAD SYNOPTIC SNOW AS WELL AS LAKE
ENHANCED SNOW ACROSS THE FCST AREA LAST NIGHT HAS SHIFTED NE INTO
QUEBEC. UPSTREAM...NEXT SHORTWAVE IS DIVING SE INTO THE DAKOTAS. A
LESS DEFINED SHORTWAVE TROF IS FARTHER N OVER NRN PORTIONS OF
MANITOBA/SASKATCHEWAN. DRYING AIR MASS...LOWERING INVERSION AND LOW
LEVEL WINDS BECOMING MORE ANTICYCLONIC WITH SFC HIGH PRES THAT IS
NOW NOSING INTO WRN UPPER MI HAVE RESULTED IN A STEADY DIMINISHING
TREND/SHIFTING OF LINGERING LES THIS AFTN. IN FACT...OVER THE
W...THERE MAY NOT BE MUCH MORE THAN SCT FLURRIES REMAINING. LAKE
EFFECT CLOUD COVER IS ALSO DIMINISHING WITH CLR SKIES NOW BEING
NOTED AROUND KIWD. TO THE W...CLOUDS IN ADVANCE OF AFOREMENTIONED
SHORTWAVES ARE SLOWLY MOVING ACROSS NRN MN.

MAIN FCST CONCERNS IN THE SHORT TERM ARE LES TRENDS TONIGHT...MIN
TEMPS TONIGHT WITH A PROBABLE PERIOD OF CLR/PARTLY CLOUDY SKIES IN
MANY AREAS AND THEN NEXT ROUND OF HEAVIER LES THAT WILL BEGIN TO
ENTER THE PICTURE WED AFTN AS SHORTWAVE TROF SWINGS SE TOWARD THE
UPPER LAKES.

TONIGHT...ARRIVAL OF WEAK SFC HIGH PRES RIDGE COMBINED WITH
STRENGTHENING LAND BREEZES WILL CONTINUE TO SHIFT LINGERING LES
OFFSHORE. OVER THE E...SHIFTING LES SHOULD BE OFFSHORE NO LATER THAN
AROUND MIDNIGHT. OVER THE W...ALTHOUGH THERE IS PROBABLY NOT MUCH
MORE THAN FLURRIES CURRENTLY REMAINING...NOCTURNAL COOLING AND LAND
BREEZE DEVELOPMENT RESULTING IN INCREASING CONVERGENCE SHOULD FAVOR
SOME REDEVELOPMENT OF LES DURING THE NIGHT. AMONG THE HIGH RES
MODELS...THERE IS DISAGREEMENT IN WHETHER SE MOVING SFC TROF WILL
SINK FAR ENOUGH S TO KEEP LES OVER THE KEWEENAW. AT THIS POINT...
BELIEVE SW FLOW ENHANCED BY LAND BREEZE WILL PUSH LES OFFSHORE...BUT
THERE IS ENOUGH UNCERTAINTY TO MAINTAIN SOME SCT -SHSN WORDING OVER
THE NRN PORTION OF THE KEWEENAW OVERNIGHT. AS FOR TEMPS...BASED ON
SATELLITE IMAGERY...IT LOOKS LIKE THERE WILL BE A DECENT PERIOD OF
CLEAR TO PARTLY CLOUDY SKIES TONIGHT OVER MUCH OF THE AREA. WITH
LIGHT WINDS AND PRECIPITABLE WATER 40-55PCT OF NORMAL...FAVORED THE
LOW END OF GUIDANCE. TEMPS SHOULD PLUMMET RAPIDLY THIS EVENING WHERE
SKIES ARE CLEAR...AND EXPECT TRADITIONAL COLD SPOTS TO FALL TO
AROUND -5F. HOWEVER...GIVEN THE SLOW ADVANCE OF UPSTREAM CLOUDS...
CLOUDS MAY BE SLOWER TO ARRIVE THAN CURRENTLY FCST. COMBINED WITH
FRESH SNOW COVER...COULD EASILY SEE TEMPS FALL TO -10F OR LWR IN THE
USUAL COLD SPOTS.

SHORTWAVE CURRENTLY MOVING INTO THE DAKOTAS WILL CONTINUE TO DROP SE
TOWARD THE TENNESSEE VALLEY TONIGHT/WED AND WILL HAVE NO INFLUENCE
HERE AS IT PASSES WELL S OF UPPER MI. OF CONCERN IS THE FOLLOWING
SHORTWAVE TROF WHICH WILL SWING SE AND EXTEND FROM JAMES BAY TO MN
BY 00Z THU. AS HEIGHT FALLS/MODEST DEEP LAYER FORCING PER QVECTORS
OVERSPREAD THE RELATIVELY WARM WATERS OF LAKE SUPERIOR...SFC TROF
MOVING OVER THE LAKE WILL SHARPEN UP...RESULTING IN INCREASING
CONVERGENCE AND INTENSIFYING LAKE ENHANCED SNOW ALONG/NEAR TROF.
EXPECT THIS TROF TO REACH THE KEWEENAW DURING THE MORNING AND THE W
IN THE AFTN. TROF PROBABLY WON`T REACH NCNTRL UPPER MI UNTIL
EVENING. NE ORIENTATION OF THE WINDS ACROSS THE KEWEENAW AFTER
TROF PASSAGE WON`T BE ESPECIALLY FAVORABLE FOR PERSISTENT HEAVIER
LAKE ENHANCED SNOW AFTER THE MAIN MDT/HVY SNOW BAND ALONG TROF
SHIFTS S. FARTHER S...SHARPER LOW-LEVEL CONVERGENCE AND BETTER
UPSLOPING IS EXPECTED INTO ONTONAGON/GOGEBIC COUNTIES...AND THIS IS
INDICATED IN MODEL GUIDANCE IN LOW-LEVEL OMEGA FIELDS. WIND FLOW
SUGGESTS LAKE NIPIGON PRECONDITONING WILL ALSO COME INTO PLAY OVER
THE FAR W. WITH THESE FAVORABLE CONDITIONS CONTINUING INTO THE WED
NIGHT...WILL HOIST A LAKE EFFECT SNOW ADVISORY FOR ONTONAGON/GOGEBIC
STARTING AT 20Z WED. IN GENERAL...A QUICK COUPLE OF INCHES OF SNOW
WILL PROBABLY OCCUR AS THE TROF MOVES ONSHORE OVER THE W.
ELSEWHERE...SOME -SN SHOULD GRADUALLY OVERSPREAD THE REST OF WRN
UPPER MI IN THE AFTN. TO THE E...IT APEARS WINDS WILL BACK
SUFFICIENTLY TO BRING SOME LES OFF LAKE MICHIGAN INTO THE FAR ERN
FCST AREA IN THE AFTN. WINDS ARE LIGHT/CONVERGENCE WEAK...SO NOT
EXPECTING MUCH WITH THE LES OFF LAKE MI WED (LESS THAN 1 INCH).

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 457 PM EST TUE NOV 25 2014

MAIN FCST CONCERNS IN THE LONG TERM WL FOCUS ON LES POTENTIAL FOR
WED NIGHT INTO THANKSGIVING AND NEED FOR HEADLINES AT SENSITIVE
TRAVEL TIME. ANOTHER ROUND OF SN WL BE POSSIBLE ON FRI/FRI NIGHT
WITH DVLPG ISENTROPIC ASCENT UNDER AN UPPER AIR PATTERN THAT WL
SHIFT TO A PROGRESSIVE...ZONAL FLOW BY THE WEEKEND. WELL BLO NORMAL
TEMPS WITH SOME RECORD LO MAX TEMPS ON THANKSGIVING WL GIVE WAY TO
MUCH WARMER WX ON SAT. ALTHOUGH SOME COLDER AIR WL RETURN FOR SUN
INTO MON...A WARMER SW FLOW ON THE WRN FLANK OF HI PRES SHIFTING TO
THE E WILL DVLP ON TUE UNDER THIS PROGRESSIVE PATTERN.

WED NGT...STEADY N BACKING NNW WIND IN THE WAKE OF PASSING NRN
STREAM SHRTWV IS FCST TO ADVECT COLDER AIR INTO THE UPR LKS WITH H85
TEMPS FALLING AS LO AS -18C OVER THE KEWEENAW BY 12Z THU...A FVRBL
SETUP FOR LES. EXPECT A PERIOD OF SOME HEAVIER LK ENHANCED SN IN THE
FAVORED SN BELTS WHEN AREA OF DPVA/DEEP LYR QVECTOR CNVGC/UVV/DEEP
MSTR ASSOCIATED WITH THE PASSING DISTURBANCE COINCIDES WITH FVRBL
UPSLOPE...WEAKLY CYC N FLOW. AREAS OVER ONTONAGON/GOGEBIC IN THE
EVNG AND MARQUETTE/ALGER COUNTIES IN THE LATER EVNG/EARLY OVERNGT
APPEAR TO BE MOST FAVORED TO SEE HEAVIER SN. ENHANCEMENT FACTOR FOR
HEAVIER SN TOTALS INCLUDE FAIRLY DEEP DGZ UP TO 4K FT. ALTHOUGH THE
SHARPEST UVV IS FCST TO BE JUST BLO THE DGZ MUCH OF THE TIME...THERE
WL BE SOME UVV IN THIS ZONE THAT SHOULD ALLOW SN/WATER RATIOS UP TO
20-25:1. ONE NEGATIVE APPEARS TO BE THE ABSENCE OF SHARP CYC FLOW/
PERSISTENT LLVL CNVGC. ALTHOUGH THE LK ENHANCEMENT WL NOT BE A
PLAYER WELL INLAND FM LK SUP...DYNAMIC FORCING SHOULD ALLOW FOR SOME
LIGHT SN EVEN OVER THE SCENTRAL. BUT ABSENCE OF HIER ABSOLUTE MSTR..
.WITH PWAT NO MORE THAN ABOUT 0.3 INCH AND H7 SPECIFIC HUMIDITY
ABOUT 1G/KG...WL LIMIT SN TOTALS TO NO MORE THAN AN INCH OR SO AWAY
FM LK ENHANCEMENT/UPSLOPE WINDS. LATER AT NGT...EXPECT THE SN TO
DIMINISH NW-SE WITH THE ARRIVAL OF DNVA/DEEP LYR QVECTOR DVGC/
SUBSIDENCE/MID LVL DRYING IN THE WAKE OF THE PASSING SHRTWV THAT IS
FCST TO STRENGTHEN INVRN AS LO AS H875-9 AS SHOWN ON NAM FCST SDNGS.
ALTHOUGH IT IS NOT COMMON PRACTICE TO ISSUE AN ADVY FOR PRIMARLIY A
3RD PERIOD EVENT...SENSITIVE TRAVEL TIME JUST BEFORE THANKSGIVING
HOLIDAY AS WELL AS FAVORABLE UPSLOPE FLOW/FAIRLY EFFICIENT SN GROWTH
PARAMETERS WARRANTS EARLY ISSUANCE OF AN LES ADVY IN THE FAVORED
AREAS OVER THE W/NCENTRAL DESPITE THE RATHER FLUFFY NATURE OF THE SN
THAT IS EXPECTED TO FALL. THE LES ADVY WL INCLUDE GOGEBIC/
ONTONAGON/MARQUETTE AND ALGER COUNTIES. AS MUCH AS 7 TO 8 INCHES OF
SN WL FALL IN THESE AREAS THRU THE ADVY PERIOD. N WINDS GUSTING UP
TO 25-30 MPH WL CAUSE SOME BLSN NEAR LK SUP WED NIGHT INTO THU MRNG.

THANKSGIVING/THU NGT...THE LLVL FLOW IS PROGGED TO BACK STEADILY AND
TURN MORE ACYC ON THANKSGIVING WITH SFC HI PRES MOVING TOWARD SW WI
LATE IN THE DAY UNDER HGT RISES/DNVA IN ADVANCE OF APRCHG SHRTWV
RDG. THE RESULT WL BE SHIFTING/DIMINISHING LES BANDS...ESPECIALLY
OVER THE W HALF. THE SN SHOWERS SHOULD END COMPLETELY AT IWD LATE IN
THE AFTN. THE LES WL BE MORE PERSISTENT IN THE FAVORED SN BELTS E OF
MARQUETTE WITH H85 THERMAL TROF/TEMPS ARND -18C REACHING THAT AREA
LATE IN THE DAY...BUT INCRSG ACYC FLOW AND ABSENCE OF SGNFT LLVL
CNVGC/LOWERING INVRN BASE TO H875-9 SHOWN ON THE FCST SDNGS UNDER
THE NEGATIVE DYNAMICS WL LIMIT SN TOTALS. THANKSGIVING WL BE QUITE
CHILLY WITH H85 THERMAL TROF PASSING OVHD AND COULD FEATURE SOME
RECORD LO MAX TEMPS. EXPECT THE LOWEST TEMPS OVER THE W HALF WHERE
BACKING FLOW WL LIMIT LK SUP MODERATION. AS THE SFC RDG AXIS SHIFTS
TO THE E AND THE FLOW BACKS TO THE W-SW...LINGERING LES WL SHIFT OUT
INTO LK SUP ON THU NGT. TEMPS COULD FALL QUICKLY IN THE EVNG TOWARD
THE LO END OF GUIDANCE BEFORE MORE HI CLDS OVERSPREAD THE AREA W-E
ASSOCIATED WITH DVLPG ISENTROPIC ASCENT IN THE SW FLOW ON THE NW
FLANK OF PRES SHIFTING INTO THE OH RIVER VALLEY AND IN ADVANCE OF
SHRTWV STREAKING EWD TOWARD MN. SOME OF THE FASTER MODELS SHOW SN
ASSOCIATED WITH THIS WAA/SHRTWV REACHING THE FAR W BY 12Z FRI...SO
WL MAINTAIN SOME LO CHC POPS IN THIS AREA LATE THU NGT.

FRI/FRI NGT...AS THE UPR TROF IN ERN NAMERICA SHIFTS TO THE E...THE
FLOW OVER THE CONUS/SRN CANADA WL BECOME MORE ZONAL. DVLPG LLVL SW
FLOW/ISENTROPIC ASCENT OVER THE GREAT LKS ON THE NW FLANK OF SFC HI
PRES SHIFTING INTO THE SRN MID ATLANTIC STATES AND IN ADVANCE OF
SHRTWV TRACKING EWD THRU MN IS PROGGED BY MOST OF THE MEDIUM RANGE
GUIDANCE TO BRING ABOUT SOME INCRSG MID LVL MSTR/PCPN ON FRI TO THE
NE OF AN H85 WARM FNT STRETCHING FM THE NRN PLAINS INTO MN AND WI.
ALTHOUGH INITIAL SHOT OF SHARPER ISENTROPIC ASCENT BEST SHOWN ON THE
280-290K SFCS/H85-7 FGEN AXIS/DEEP LYR QVECTOR CNVGC IS FCST TO
IMPACT NRN WI ON FRI MRNG...THIS WAA/FORCING MAY SHIFT FARTHER N
INTO UPR MI DURING THE DAY. H7 SPECIFIC HUMIDITY IS FCST AS HI AS 3
G/KG...SO NOT OUT OF THE QUESTION THERE COULD BE SOME MODERATE SN
AMOUNTS APRCHG ADVY CRITERIA OVER THE SRN CWA. AS THE H925 WINDS
BECOME MORE S IN THE PRESENCE OF H85 TEMPS IN THE -8 TO -10C
RANGE...LES OFF LK MI WL IMPACT THE ERN CWA. WL MAINTAIN THE HIER
POPS/QPF IN THIS AREA. ON FRI NGT...MORE NOTABLE MODEL DIFFERENCES
ARE SHOWING UP WITH THE 12Z GFS SHOWING A MORE WNW VS W FLOW ALOFT
AND A STRONGER SHRTWV/SFC LO TRACKING FASTER E ACROSS  LK SUP ON FRI
NGT...WITH CYC NW FLOW OF COLDER AIR DVLPG OVER THE CWA LATE FRI
NGT. THIS SOLUTION IS VERY MUCH AN OUTLIER EVEN AMONG THE MOST
RECENT GFS ENSEMBLE GUIDANCE... SO TENDED TO FOLLOW THE MORE
CONSISTENT 12Z CNDN/00Z AND 12Z ECMWF MODELS. THIS GUIDANCE SHOWS A
SLOWER SFC LO AND MORE AGGRESSIVE PUSH TO THE NE OF H85 WARM
FNT...WITH H85 TEMPS RISING ABOVE 0C OVER THE SCENTRAL CWA BY 12Z
SAT ACCOMPANYING DRY SLOTTING/LOWERING POPS OVER THE SRN TIER. WITH
ECWMF SDNGS SHOWING LINGERING LLVL MSTR BLO THE WARMING/DRYING WARM
NOSE ARND H85...ADDED A MENTION OF SOME FREEZING DZ OVER THE SW CWA.

SAT/SAT NGT...SHRTWV EMBEDDED IN ZONAL FLOW OVER SRN CANADA WL
STREAM E...WITH ACCOMPANYING SFC LO STREAKING ENEWD THRU ONTARIO AND
THEN DRAGGING A COLD FNT ACRS THE CWA SAT NGT. AHEAD OF THIS FNT...
MORE CONSISTENT...FAVORED 12Z ECMWF/CNDN MODELS SHOW WARM SURGE INTO
THE UPR LKS WITH H85 TEMPS RISING AS HI AS 8-10C OVER THE SRN TIER
ON SAT UNDER SOME MID LVL DRYING. TENDED TO CUT POPS OVER THE SRN
TIER...WHERE THE ECMWF AND CNDN MODELS SHOW MORE AGGRESSIVE MID LVL
DRYING FARTHER FM THE LO TRACK. CONTINUED TO MENTION SOME RA OR
FREEZING DZ IN THESE AREAS AS WELL. FARTHER TO THE N CLOSER TO THE
LO TRACK AND SOMEWHAT HIER CHC POPS...INCLUDED MENTION OF FREEZING
RA AND RA IN ADDITION TO SN IN CASE THE AIRMASS IS A BIT COLDER. IF
SFC TEMPS END UP HIER THAN CURRENTLY FCST...LATER SHIFTS MAY BE ABLE
TO CUT BACK ON THE FREEZING DZ/RA AND GO WITH PLAIN RA. RIGHT NOW...
LOOKS LIKE ANY ICE ACCUMULATION WL BE MINOR.

EXTENDED...MUCH COLDER AIR...WITH H85 TEMPS FCST AS LO AS -18C BY
00Z MON...AND SOME LK EFFECT SN WL FOLLOW ON SUN UNDER NW FLOW BTWN
DEPARTING COLD FNT AND CNDN HI PRES BLDG E THRU THE NRN PLAINS. BUT
SINCE THE UPR FLOW WL REMAIN FAIRLY PROGRESSIVE...THE SFC HI PRES WL
SHIFT THRU THE GREAT LKS ON MON AND INTO NEW ENGLAND TUE AS UPR RDG
BLDS INTO THE UPR LKS ON TUE. THE RESULT SHOULD BE DIMINISHING LES
ON MON WITH DRY WX LINGERING INTO TUE. WARMER SW FLOW ON THE WRN
FLANK OF DEPARTING SFC HI PRES MAY DRAW ENUF MSTR TO THE N ON TUE TO
BRING A RETURN OF SOME SN OR A RA/SN MIX.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1248 PM EST TUE NOV 25 2014

DRIER AIR AND BACKING WINDS TO THE SW WITH APPROACHING WEAK SFC HIGH
PRES RIDGE WILL RESULT IN LAKE EFFECT -SHSN ENDING AND MVFR
CONDITIONS IMPROVING TO VFR AT KIWD DURING THE MID AFTN AND AT KSAW
LATE THIS AFTN. MAY YET SEE SOME BRIEF IFR CONDITIONS AT KSAW BASED
ON RADAR IMAGERY SHOWING HEAVIER SNOW SHOWERS IN NCNTRL UPPER MI.
VFR CONDITIONS WILL CONTINUE AT KIWD/KSAW TONIGHT. NEXT APPROACHING
DISTURBANCE MAY BRING SOME -SN/MVFR CONDITIONS TO KIWD LATE WED
MORNING. AT KCMX...WINDS WILL PROBABLY RETAIN ENOUGH OVERWATER
COMPONENT TO MAINTAIN MVFR CONDITIONS THRU THE NIGHT EVEN THOUGH
-SHSN SHOULD END. BEFORE THE -SHSN END...THERE MAY BE A PERIOD OF
SOMEWHAT HEAVIER SNOW SHOWERS AT KCMX THIS EVENING.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 450 PM EST TUE NOV 25 2014

PRES GRADIENT RAPIDLY WEAKENS TONIGHT WITH A WEAK SFC TROF DROPPING
SE OVER LAKE SUPERIOR. THIS WILL RESULT IN WINDS DIMINISHING TO UNDER
20KT ACROSS THE LAKE. STRONG HIGH PRES WILL THEN BUILD SE INTO THE
CANADIAN PRAIRIES WED AND INTO THE NRN PLAINS WED NIGHT. THIS WILL
PUSH THE TROF SE AND TIGHTEN THE PRES GRADIENT. AS A RESULT... WITH
THE TROF PASSAGE...EXPECT NORTHERLY WINDS TO RAMP UP TO 20-30KT FROM
NW TO SE WED/WED NIGHT. NOT OUT OF THE QUESTION THAT THERE COULD BE
SOME GALE FORCE GUSTS OVER THE CNTRL PORTION OF LAKE SUPERIOR. WINDS
WILL THEN DIMINISH TO UNDER 20KT W TO E THU/THU NIGHT AS HIGH PRES
RIDGE ARRIVES. WITH ANOTHER COLD FRONT PUSHING ACROSS THE UPPER LAKES
SAT...EXPECT INCREASING WINDS TO 15-25KT FRI/FRI NIGHT AHEAD OF
FRONT. BEHIND FRONT...NW WINDS MAY REACH 20-30KT LATE SAT/SUN.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW ADVISORY FROM 10 PM WEDNESDAY TO 1 PM EST
     THURSDAY FOR MIZ006.

  LAKE EFFECT SNOW ADVISORY FROM 7 PM WEDNESDAY TO 10 AM EST
     THURSDAY FOR MIZ005.

  LAKE EFFECT SNOW ADVISORY FROM 3 PM EST /2 PM CST/ WEDNESDAY TO
     10 AM EST /9 AM CST/ THURSDAY FOR MIZ002-009.

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

$$

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




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