Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 262340
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
640 PM EST WED NOV 26 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...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 342 PM EST WED NOV 26 2014

THU NIGHT...THE LINGERING LES WILL DIMINISH AS THE SFC RIDGE AXIS
SLIDES THROUGH THE WRN LAKES AND LOW LEVEL WINDS BACK TO THE SW.
WITH LIGHT WINDS AND A PERIOD OF CLEARING OVER THE INTERIOR WEST
DURING THE EVENING...TEMPS WILL DROP QUICKLY TO MINS BELOW GUIDANCE
BEFORE RECOVERING OVERNIGHT AS CLOUDS MOVE IN. MODELS WERE
CONSISTENT IN BRINGING POTENTIAL FOR SOME LIGHT SNOW INTO THE WEST
LATE WITH THE DEVELOPING WAA PATTERN.

FRI...SNOW IS EXPECTED TO SPREAD ACROSS THE REGION WITH FAVORABLE
MOISTURE ADVECTION AND ISENTROPIC LIFT THROUGH THE 850-700 MB
FRONTAL ZONE. 3 G/KG MOISTURE AVAILABLE IN THE 285K-295K LAYER
DURING THE PERIOD OF STRONGEST LIFT IS CONSISTENT WITH POTENTIAL FOR
2 TO 4 INCHES OF SNOW WITH MODELS CONSENSUS QPF OF 0.10 TO 0.20
INCHES AND SLR VALUES FROM AROUND 15/1-20/1. THERE IS STILL SOME
UNCERTAINTY WHERE THE BAND OF HEAVIER SNOW WILL DEVELOP AS THE 12Z
NAM BRINGS GREATER AMOUNTS OF PCPN INTO SRN UPPER MI COMPARED TO THE
GFS AND ECMWF. THERE WILL ALSO BE THE POTENTIAL FOR A BAND OF LAKE
ENHANCED SNOW OFF OF LAKE MI THAT COULD SPREAD EASTWARD FROM NEAR
THE GARDEN PENINSULA INTO LUCE COUNTY. SINCE THE STRONGEST LOW
LEVEL CONV IS EXPECTED TO MOVE STEADILY TO THE EAST...SNOW AMOUNTS
IN ANY ONE LOCATION SHOULD BE LIMITED. HOWEVER...CONFIDENCE IS LOWER
FOR THE POSITION/STRENGTH OF THIS FEATURE THAT COULD ADD SEVERAL
INCHES TO THE SNOW TOTALS.

FRI NIGHT INTO SAT...SFC LOW PRES IS FCST TO SPREAD FROM THE NRN
PLAINS TO THE UPPER MS VALLEY WITH CONTINUED WAA BRINGING
SUBSTANTIAL 850 MB WARMING. NAM/GFS 285-295K ISENTROPIC PROGS
SUGGEST THAT THE STRONGEST LIFT AND DEEPEST MOISTURE WILL REMAIN
ACROSS LAKE SUPERIOR AND FAR NRN UPPER MI. WITH A PROMINENT 850-700
MB DRY LAYER DEVELOPING TO THE SOUTH...FREEZING DRIZZLE WILL BE
POSSIBLE ALONG WITH SOME LIGHT SNOW OR FLURRIES AS ICE NUCLEI BECOME
MORE SCARCE. ANY PCPN AMOUNTS ARE EXPECTED TO BE LIGHT WITH
ONLY A FEW HUNDREDTHS OF AN INCH AT MOST. THERE MAY ALSO BE ENOUGH
900-700 MB WARMING INTO THE AREA OF DEEPER MOISTURE FOR SOME
FZRA.

SAT NIGHT AND SUN...LOW PRES LIFTING NE TOWARD JAMES BAY SAT NIGHT
WILL DRAG A COLD FRONT THROUGH THE NRN LAKES WITH MUCH COLDER AIR
MOVING IN ON NW WINDS. WITH 850 MB TEMPS FALLING TO NEAR -18C...LES
WILL BE LIKELY FOR NW WIND SNOW BELTS. A LIMITING FACTOR FOR HEAVIER
SNOW WILL BE SUBSTANTIAL 850-700 MB DRYING WITH BACKING AND
INCREASING ACYC LOW LEVEL WINDS FROM LATE SUN INTO SUN NIGHT.

MON-WED...THE GFS/GEFS AND ECMWF WERE IN REASONABLE AGREEMENT WITH
THE PATTERN INTO NEXT WEEK WITH HIGH PRES BUILDING INTO THE REGION
MON INTO MON NIGHT BRINGING DIMINISHING LES. ANOTHER MID LEVEL AND
SFC TROUGH MOVING THROUGH TUE INTO TUE NIGHT COULD BRING SOME LIGHT
SNOW TO THE AREA. THE MODELS HAVE TRENDED TOWARD KEEPING COLDER
ACROSS REGION THAT WOULD KEEP ANY PCPN AS SNOW WITH MAX TEMPS
RECOVERING INTO THE MID 20S TO AROUND 30 BY TUE AND WED.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 639 PM EST WED NOV 26 2014

PERIODS OF HEAVIER LK EFFECT SN AND AT LEAST OCNL LIFR CONDITIONS
ASSOCIATED WITH THE PASSAGE OF A LO PRES TROF AND WSHFT TO A FVRBL
UPSLOPE N DIRECTION WL IMPACT MAINLY IWD AND SAW INTO THE EARLY MRNG
HRS ON THANKSGIVING BEFORE THE ARRIVAL OF LARGE SCALE SUBSIDENCE/
DRYING BEHIND THE TROF RESULTS IN A STEADY IMPROVEMENT LATER TNGT/
THU MRNG. SINCE THE N WIND IS NOT A FAVORABLE WIND FOR CMX...MVFR/
ONLY OCNL IFR VSBYS WL BE THE RULE AT THAT TERMINAL. GUSTY N WINDS
RIGHT BEHIND THE TROF PASSAGE WL ALSO DIMINISH LATER TNGT/EARLY THU
MRNG UNDER WEAKENING PRES GRADIENT ASSOCIATED WITH SLOWLY APRCHG HI
PRES RDG. AS THE HI AND ACCOMPANYING DRIER AIR EDGE CLOSER ON
THANKSGIVING...THE LLVL WINDS WL BACK TOWARD THE NW AND THEN THE
W... RESULTING IN A RETURN TO VFR CONDITIONS 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 FROM 10 PM THIS EVENING TO 1 PM EST
     THURSDAY FOR MIZ006.

  LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THURSDAY FOR MIZ004.

  LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST THURSDAY FOR MIZ005.

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

  LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THURSDAY FOR MIZ001-003.

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

$$

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




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