Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 202107
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
407 PM EST THU NOV 20 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 406 PM EST THU NOV 20 2014

OVERALL CONDITIONS SHOULD IMPROVE OVER THE NEXT 12 TO 18 HOURS AS
LAKE EFFECT SNOW DIMINISHES FOR THE NORTHWEST WIND SNOW BELTS.

MODERATE TO HEAVY LAKE EFFECT SNOW BANDS HAVE BEEN RATHER PERSISTENT
FOR THE NW-WIND SNOW BELTS TODAY...ESPECIALLY AROUND IRONWOOD AND
GRAND MARAIS. HOWEVER...LOWERING INVERSION HEIGHTS ARE FINALLY
MAKING THEIR PRESENCE FELT ACROSS THE WEST AS ELEVATED RADAR RETURNS
ARE DIMINISHING. THIS TREND IS EXPECTED TO CONTINUE THROUGH THE
EVENING...LEAVING LIGHT TO SOMETIMES MODERATE SHOWERS THROUGH THE
NIGHT. ADDITIONALLY...DEEPER MOISTURE ASSOCIATED WITH A DEPARTING
MID-LEVEL TROUGH WILL CONTINUE TO DIMINISH THROUGH THE NIGHT. GIVEN
RECENT RADAR TRENDS AND HIGH-RES GUIDANCE...FEEL COMFORTABLE LETTING
ALL WESTERN LES ADVISORIES EXPIRE AT 00Z. HOWEVER...AS LOW-LEVEL
FLOW BEGINS TO BACK IN RESPONSE TO A SFC HIGH PASSING SW OF THE
REGION...EXPECT LAKE EFFECT BANDS TO FOCUS ACROSS THE KEWEENAW
OVERNIGHT. ANY ENHANCED CONVERGENT AREAS SHOULD BE RATHER TRANSIENT
WITH THE GRADUALLY BACKING WINDS...SO DO NOT THINK ANY STRONGER
BANDS WILL REMAIN IN ONE PLACE FOR TOO LONG. WITH THAT SAID...AN
ADDITIONAL 1 TO 3 INCHES WILL BE POSSIBLE DURING THE OVERNIGHT HOURS.

ACROSS THE EAST...CONVECTIVE CLOUDS DEPTHS OF 8-10 KFT ENCOMPASSING
THE DGZ COMBINED WITH LONGER FETCH WILL ALLOW FOR MODERATE TO
SOMETIMES HEAVY LAKE EFFECT BANDS TO PERSIST ACROSS THE WARNED AREA
OVER AND EAST OF MUNISING THROUGH THIS EVENING. THE BANDS ARE
BEGINNING TO SHIFT EASTWARD LATE THIS AFTERNOON AS LOW-LEVEL FLOW
BACKS SLIGHTLY. HOWEVER...A WEAK SFC TROUGH NOTED IN THE SFC WIND
FIELD OVER NE LAKE SUPERIOR AND ON SHORT-TERM MODEL GUIDANCE WILL
PUSH ACROSS THE EASTERN CWA LATE THIS EVENING INTO THE OVERNIGHT
HOURS. VEERING WINDS BEHIND THE TROUGH SHOULD PUSH THE LES BANDS
BACK WESTWARD TO AT LEAST MUNISING. WITH A LAND-BREEZE-ENHANCED
WESTERLY GRADIENT FLOW DEVELOPING OVER THE CENTRAL CWA AND AN
EASTERLY LAND BREEZE DEVELOPING OVER ONTARIO TONIGHT...AN AREA OF
STRONGER CONVERGENCE MAY FOCUS A MORE ROBUST LES BAND OVER EASTERN
ALGER COUNTY LATE TONIGHT. BY SUNRISE...INVERSION HEIGHTS BEGIN A
QUICK DESCENT TO UNDER 5KFT. WITH THE BACKING WINDS...THIS WILL PUSH
ALL OF THE LES OVER LAKE SUPERIOR BY LATE MORNING.

SOME CLEARING SKIES TONIGHT ALONG WITH DECREASING WINDS ASSOCIATED
WITH THE SFC RIDGE TO THE SW WILL ALLOW FOR GOOD RADIATIONAL COOLING
TONIGHT FOR WESTERN AND CENTRAL UPPER MI. WENT LOWER THAN MOST
GUIDANCE...BELOW ZERO...FOR MUCH OF THE INTERIOR. GIVEN TEMPS OF 0
TO -10F THIS MORNING UNDER THE SAME AIRMASS...AND THE START OF WAA
OUT WEST...DID NOT WANT TO GO TOO MUCH COLDER.

NOT MUCH TO BE SAID FOR FRIDAY AS WAA BEGINS ACROSS THE CWA. OTHER
THAN SOME MID TO HIGH CLOUD-COVER FILTERING OVER THE REGION IN THE
AFTERNOON...SKIES SHOULD BE MOSTLY SUNNY. SW WINDS WILL GRADUALLY
INCREASE THROUGH THE AFTERNOON...ESPECIALLY WEST...SO SOME BLOWING
SNOW WILL BE POSSIBLE.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 451 AM EST THU NOV 20 2014

MAIN FCST CONCERNS IN THE MEDIUM/EXTENDED RANGE WL BE THE POTENTIAL
FOR SOME MIXED PCPN EARLY IN THE WEEKEND WITH A STRENGTHENING SW
FLOW DRAWING MUCH WARMER AIR...ALBEIT JUST A BIT ABOVE NORMAL FOR
THIS TIME OF YEAR...BACK INTO THE UPR LKS. FOCUS FOR LATER IN THE
WEEKEND AND EARLY NEXT WEEK WL TURN TO A MORE SUBSTANTIAL PCPN EVENT
THAT WL ACCOMPANY A RAPIDLY DEEPENING LO PRES MOVING NNEWD INTO THE
UPR LKS ON MON AS A PAIR OF SHRTWVS PHASE AND DEEPEN THE UPR TROF
JUST TO THE W. RIGHT NOW IT APPEARS THE BULK OF THE PCPN ON SUN THRU
SUN NGT WL BE IN THE FORM OF RA. MUCH COLDER AIR AND LK ENHANCED/LES
CHANCES WL RETURN EARLY NEXT WEEK.

FRI...AS THE TROF OVER ERN AMERICA SHIFTS TO THE E...UPR RDG IN THE
PLAINS WILL SHIFT TOWARD THE GREAT LKS...LEADING TO 12HR H5 HGT
RISES UP TO 180M. LINGERING LES OVER THE TIP OF THE KEWEENAW AND
NEAR LK SUP E OF GRAND MARAIS WL DIMINISH AND SHIFT OUT INTO LK SUP
WITH WSHFT TO THE SW AS SFC HI PRES IN THE OH RIVER VALLEY SHIFTS E
INTO THE MID ATLANTIC STATES. STRENGTHENING ISENTROPIC ASCENT WL
LEAD TO QUITE A BIT OF HI CLDS. IN THE STRENGTHENING SW FLOW...H85
TEMPS ARE FCST TO RISE ABOUT 10C THRU THE DAY...REACHING NEAR OR
JUST ABOVE 0C OVER THE W BY 00Z SAT. FCST SDNGS SHOW VERY STABLE
LLVL LAPSE RATES...SO THE WARMING WL NOT BE AS PRONOUNCED AT THE
SFC...WITH HI TEMPS IN THE 20S AT MOST SPOTS. EXPECT THE LOWEST MAX
TEMPS OVER THE CENTRAL...WHERE THE HI MAY HOLD IN THE UPPER TEENS. A
STEADY SSW WIND WL MAKE THE AIR FEEL COLDER.

FRI NGT/SAT...WITH INCREASING ISENTROPIC ASCENT IN THE STRENGTHENING
WSW FLOW BTWN HI PRES MOVING OFF THE E COAST AND LO PRES MOVING
ACROSS SCNTRL CANADA...MODELS ARE GENERATING SOME VERY LIGHT PCPN
OVER AT LEAST PARTS OF THE FCST AREA...MAINLY LATE FRI NIGHT INTO
SAT AFTN OVER THE ERN FCST AREA WHERE LONGER DURATION OF ISENTROPIC
ASCENT FAVORS MORE SGNFT MOISTENING SHOWN ON FCST SOUNDINGS. BUT
PERSISTENCE OF DRIER AIR IN THE H85-7 LYR SHOWN ON THE 00Z GFS/NAM
FCST SDNGS EVEN OVER THE E WARRANTS JUST CHC POPS THERE...WITH
NOTHING MORE THAN SCHC POPS ELSEWHERE. ALTHOUGH FCST SDNGS SHOW AN
ELEVATED WARM LYR/H85 TEMPS ABOVE 0C...DRY NATURE OF THIS LYR WITH
WBLB TEMPS NO MORE THAN ABOUT 0C WOULD ALLOW SUFFICIENT EVAPORATIVE
COOLING FOR SN TO BE THE PTYPE IF PCPN IS ABLE TO REACH THE GROUND
FM THE HIER MOIST LYR. BUT THE INCRSGLY MOIST BUT SHALLOW NEAR SFC
LYR WL BE WARMER THAN -10C...WHICH WOULD SUPPORT DRIZZLE/FREEZING
DRIZZLE/SN GRAINS AS THE PTYPES. SO WL RETAIN THE WINTRY MIX SHOWN
IN CURRENT FCST. MODELS ALSO SHOW A TRAILING SHRTWV WITHIN THE ZONAL
FLOW MOVING INTO THE UPR LKS LATE ON SAT...BUT THE GFS IS THE ONLY
MODEL THAT SHOWS SGNFT MOISTENING AND GENERATES PCPN. GIVEN THE
DRYING NATURE OF THE MID LVLS FOLLOWING THE EXIT OF THE BETTER
ISENTROPIC ASCENT...WL FAVOR THE DRT BULK OF THE GUIDANCE. AS FOR
TEMPS...STRENGTHENING SSW FLOW/WARMING LLVL TEMPS/INCRSG CLDS WL
FAVOR A RELATIVELY MODEST DIURNAL TEMP FALL ON FRI NGT...WITH TEMPS
BOTTOMING OUT RELATIVELY EARLY AND THEN RISING THRU THE NGT. TEMPS
ON SAT SHOULD RISE ABOVE FREEZING EVERYWHERE.

SAT NGT...HGT RISES/DNVA/DEEP LYR QVECTOR DVGC IN THE WAKE OF THE
PASSING SHRTWV SHOULD BRING ABOUT A DRY PERIOD AT MOST PLACES. SOME
OF THE MODELS GENERATE SOME LIGHT QPF OVER MAINLY THE SE CWA. SINCE
FCST SDNGS CONTINUE TO SHOW A LINGERING...SHALLOW MOIST LYR NEAR THE
SFC BLO QUITE A BIT OF MID LVL DRY AIR...ANY PCPN WOULD BE IN THE
FORM OF FREEZING DRIZZLE/DRIZZLE/SN GRAINS. WITH LIGHTER WINDS UNDER
THE MID LVL DRYING...MIN TEMPS SHOULD FALL INTO THE 20S TO ARND 30
AT MOST PLACES AWAY FM THE GREAT LKS.

SUN THRU MON...NEGATIVELY TILTED SHRTWV LIFTING NNEWD FM THE
SOUTHERN PLAINS IS FCST TO MOVE INTO THE WESTERN GREAT LKS BY LATE
SUN AND PHASE WITH ANOTHER SHRTWV DROPPING SEWD THRU THE NRN
PLAINS...DVLPG A CUTOFF H5 LO NEAR UPR MI ON MON. THE SFC LO PRES
ASSOCIATED WITH THE SRN PLAINS SHRTWV IS FCST TO DEEPEN STEADILY
DURING THIS PHASING PROCESS...WITH RECENT GFS/ECMWF RUNS SHOWING THE
CENTRAL PRES OF THIS LO FALLING AS LO AS 971-974MB ON MON. GIVEN THE
PHASING BTWN THE SHRTWVS/DEEPENING SFC LO...SUSPECT THE FARTHER W
TRACK FOR THE SFC LO AS INDICATED BY THE 12Z ECMWF MOVING TO NEAR
BARAGA AT 18Z MON MAY BE THE BEST FCST. THE 00Z GFS/ECMWF ARE IN
GOOD AGREEMENT SHOWING A FCST TRACK ONLY SLIGHTLY TO E...PASSING
BTWN MARQUETTE-MUNISING AS IT MOVES N INTO CENTRAL LK SUP.
IMPRESSIVE DYANMIC FORCING/DEEP LYR QVECTOR CNVGC IS FCST TO ARRIVE
FM THE S DURING THE DAY... RESULTING IN DEEP SATURATION AS EARLY AS
18Z OVER THE S AT MENOMINEE AND OVER THE REST OF THE CWA THRU THE
AFTN. WHILE THERE MAY BE SOME FREEZING DRIZZLE IN THE MRNG WITH SOME
RETURN OF LLVL MSTR BEFORE THE DEEPER MSTR/DYNAMIC FORCING ARRIVES
S-N IN THE AFTN...FCST SDNGS INDICATE THE LLVLS WL WARM ABOVE
FREEZING BY THE TIME THE MORE WIDESPREAD PCPN ARRIVES IN THE FORM OF
RA. AS THE SFC LO TRACKS MORE SLOWLY TO THE NE...COLDER AIR WL
RETURN IN THE CYC NW FLOW LEFT IN THE WAKE OF THE LO BEGINNING LATE
SUN NGT THRU MON. HOW QUICKLY THIS COLD AIR RETURNS WL DETERMINE
WHEN WRAP AROUND PCPN WL CHG BACK TO SN. SINCE A FARTHER W TRACK
SEEMS TO BE THE BEST BET...TENDED TO PSUH BACK IN TIME THE CHANGE FM
RA TO SN. THE BEST CHC FOR SGNFT ACCUMULATING SN WL BE OVER THE WRN
CWA ON MON...WHICH WL HAVE A BETTER SHOT TO BE ON THE CYC SIDE OF
THE H7-5 LO TRACK/UNDER THE COMMA HEAD AND WHERE LLVL WINDS WL
UPSLOPE. DRY SLOTTING MAY IMPACT THE CWA FARTHER TO THE E AND HOLD
DOWN ADDITIONAL PCPN AMOUNTS ONCE THE AIR IS COLD ENUF FOR MAINLY SN
LATER MON/MON NGT.

TUE/WED...AS THE LO MARCHES TO THE NE AND H5 TROF AXIS SHIFTS TO THE
E ACRS THE UPR LKS...DEEP CYC NW FLOW/AXIS OF DEEPER MSTR WL LIKELY
BRING A PERIOD OF LK ENHANCED SN ON TUE WITH THE RETURN OF H85 TEMPS
AS LO AS -15C. SUSPECT WINTER WX HEADLINES WL BE NECESSARY AT SOME
POINT FOR AT LEAST THE WRN CWA DURING THE MON-TUE NGT TIME FRAME.
OPTED TO MENTION THIS POTENTIAL IN THE HWO AND ADD SOME ENHANCEMENT
IN THE EHWO GRIDS. WITH THE EXIT OF THE DEEPER MSTR/CYC FLOW ON WED
AHEAD OF ARCTIC HI PRES MOVING INTO SCENTRAL CANADA...THE PCPN ON
WED SHOULD RETURN TO A PURE LES MODE WITH THE -15C H85 TEMPS.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1243 PM EST THU NOV 20 2014

LAKE EFFECT SNOW WILL CONTINUE FOR ALL SITES...ESPECIALLY
IWD...THROUGH THE REMAINDER OF THE AFTERNOON. VISIBILITIES WILL BE
QUITE VARIABLE FOR CMX AND IWD THROUGH 00Z...WITH IFR VIS PREVALENT.
SOME STRONGER -SHSN BANDS HAVE FOCUSED AROUND IWD EARLY THIS
AFTERNOON...SO VIS MAY BRIEFLY FALL TO LANDING MINS OVER THE NEXT
FEW HOURS. BACKING WINDS THIS EVENING WILL THEN END THE LAKE EFFECT
FOR IWD AND SAW. CMX SHOULD SEE CONTINUING -SHSN THROUGH MUCH OF THE
NIGHT UNTIL THE WINDS BACK MORE TO THE SW FRIDAY MORNING.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 406 PM EST THU NOV 20 2014

NW WINDS OF 20 TO 30 KNOTS ACROSS THE EASTERN LAKE WILL GIVE WAY TO
WEST WINDS OF 15 TO 25 KNOTS ACROSS MUCH OF LAKE SUPERIOR TONIGHT AS
A SURFACE RIDGE PASSES SW OF THE AREA. THEN...AS LOW PRESSURE BUILDS
OVER SOUTH-CENTRAL CANADA ON FRIDAY...EXPECT INCREASING SW FLOW
THROUGHOUT THE DAY. SW WINDS OF 20-30 KNOTS WILL BE COMMON FRIDAY
NIGHT...WITH SOME GALES TO 35 KNOTS POSSIBLE ACROSS MAINLY THE
WESTERN LAKE. LAKE STABILITY MAY KEEP OVERALL WINDS BELOW GALES
EXCEPT FOR THE HIGH PLATFORMS. THESE WINDS WILL QUICKLY DIMINISH TO
UNDER 20 KNOTS BY SATURDAY EVENING. THEN...AS TWO LOW PRESSURE
SYSTEMS DEVELOPING OVER THE NORTHERN PLAINS AND GULF COAST MERGE
OVER THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY...EXPECT A ROUND
OF N TO NW GALES.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW WARNING UNTIL 10 AM EST FRIDAY FOR MIZ006-007-
     085.

  LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
     FOR MIZ001>003-009.

LAKE SUPERIOR...
  GALE WATCH FROM FRIDAY EVENING THROUGH SATURDAY MORNING FOR
     LSZ263-264.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KLUBER
LONG TERM...KC
AVIATION...KLUBER
MARINE...KLUBER





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