Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 171008
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
508 AM EST WED DEC 17 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM EST WED DEC 17 2014

WV IMAGERY STILL SHOWS TWO UPPER LEVEL WAVES OVER THE GREAT LAKES
REGION...ONE OVER SOUTHEAST ONTARIO AND THE OTHER ELONGATED
SHORTWAVE STRETCHING FROM EASTERN NORTH DAKOTA THROUGH CENTRAL
WISCONSIN. MOIST AIR IS ROTATING/PIVOTING WESTWARD ON THE NORTH SIDE
OF THE ELONGATED SHORTWAVE...AS EASTERLY MID LEVEL FLOW IS IN
PLACE. AT THE SURFACE...A 1007MB LOW IS LOCATED OVER SOUTHEASTERN
ONTARIO AND THERE IS A TROUGH STRETCHING TO THE WEST-NORTHWEST
ACROSS NORTHERN UPPER MICHIGAN AND SOUTHERN LAKE SUPERIOR. THIS
SURFACE TO 700MB TROUGH HAS BEEN THE FOCUS FOR THE SNOW OVER THE
LAST 12 HOURS AS IT CONTINUES TO PIVOT OVER THE AREA. STILL SEEING
SOME STRONGER BANDS OF SNOW OVER PORTIONS OF WESTERN AND CENTRAL
UPPER MICHIGAN EARLY THIS MORNING...ESPECIALLY OVER THE NORTH
CENTRAL U.P. AND STRETCHING FORM SOUTHERN HOUGHTON THROUGH
NORTHEASTERN IRON COUNTY INTO DICKINSON/MENOMINEE COUNTIES.
THAT BAND IN IRON/DICKINSON/MENOMINEE COUNTIES HAS LIKELY BEEN
PRODUCING 0.5-1.0 INCH AN HOUR SNOWFALL RATES IN THE LAST HOUR. OVER
THE WEST...RAP ANALYZED 850MB TEMPS AND NORTH-NORTHWESTERLY LOW
LEVEL WINDS HAS LIKELY BEEN PROVIDING SOME LAKE/TERRAIN ENHANCEMENT
IN THOSE AREAS AND AIDING SLIGHTLY STRONGER SNOW THAN SHOWN WITH THE
SYNOPTIC SNOW ON RADAR. WHILE MOST LOCATIONS OVER THE WEST HAS SEEN
SNOW THROUGH THE NIGHT...IRONWOOD DID GET DRY SLOTTED LAST EVENING
AND INTO THE OVERNIGHT HOURS WHICH LIMITED THE VISIBILITY
RESTRICTIONS. LOOKING AT WEBCAMS TOWARDS WAKEFIELD...IT DOES APPEAR
THAT IT IS SNOWING OVER PARTS OF GOGEBIC COUNTY AT THIS TIME.

FOR TODAY...THE ELONGATED SHORTWAVE WILL BEGIN TO PICK UP SPEED
HEADING TO THE SOUTHEAST THIS MORNING AND THEN QUICKLY DROP THROUGH
THE LOWER GREAT LAKES THIS AFTERNOON AND EVENING. THAT QUICK
DEPARTURE WILL LEAD TO THE SURFACE-850MB TROUGH SHIFTING SOUTH OF
THE CWA THIS MORNING AND PULL THE LARGER SCALE SUPPORT OUT OF THE
AREA. THUS...EXPECT A DIMINISHMENT OF THE SYNOPTIC SNOW THROUGH THE
MORNING HOURS AND LARGELY BE DONE BY THE AFTERNOON. THE AREA WHERE
THE SNOW WILL HANG ON THE LONGEST WILL BE THE AREAS SUPPORTED BY THE
NORTHERLY LAKE/TERRAIN ENHANCED SNOW...BUT EVEN THAT WILL LIKELY BE
ON THE DIMINISHING TREND DURING THE AFTERNOON. THAT IS DUE TO THE
DRY AIR THAT IS CURRENTLY IN FAR NORTHER ONTARIO QUICKLY DROPPING
OVER NORTHERN LAKE SUPERIOR BY EARLY AFTERNOON AND THEN OVER THE
SOUTHERN LAKE AND NORTHWESTERN UPPER MICHIGAN BY 00Z THURSDAY. THAT
DRY AIR WILL COMBINE WITH THE WARMING LOW LEVEL TEMPERATURES (850MB
TEMPERATURES RISING FROM -14C AT 12Z THIS MORNING TO -9C AT 00Z
THURSDAY) TO LIMIT THE LAKE ENHANCEMENT POTENTIAL. THE 00Z RUNS
APPEAR TO BE EVEN FASTER THAN THE TREND THEY SHOWED 24 HOURS
AGO...SO WILL REALLY SHOW A QUICK DIMINISHMENT TO THE SNOW THIS
AFTERNOON THROUGH THE EVENING HOURS. EXPECT THE SNOW TO LINGER THE
LONGEST OVER THE NORTH CENTRAL AND FAR WEST (LATE EVENING OR EARLY
OVERNIGHT) WHERE THERE IS THE FAVORABLE UPSLOPE ASSISTANCE.

AS FOR SNOWFALL AMOUNTS...HAVE ANOTHER 0.5-2 INCHES OF ACCUMULATION
FOR THE SYNOPTIC SNOWFALL AWAY FROM ANY LAKE/TERRAIN ENHANCEMENT.
WHERE THE ENHANCEMENT OCCURS...COULD SEE AN ADDITIONAL 2-4 INCHES
THROUGH THE AFTERNOON...WITH SOME LOCALLY HIGHER AMOUNTS TO 5
INCHES OVER THE HURON MOUNTAINS. FOR THE HEADLINES...WILL KEEP THE
ADVISORIES GOING THAT ARE ALREADY IN PLACE. WILL TRIM THE END TIME
OF THE KEWEENAW ADVISORY A FEW HOURS EARLIER TO SHOW THE
DIMINISHING TREND WITH THE DRY AIR AND WARMING. THE WARNINGS MAY BE
A LITTLE ON THE MARGINAL SIDE FOR THE REST OF THE WAY...WITH THE
MAIN SNOW ALREADY HAVING OCCURRED. BUT...SINCE WEBCAMS SHOW ROADS
STILL SNOW COVERED AND ANOTHER FEW INCHES EXPECTED...WILL LEAVE
THEM IN PLACE TO COVER THE MORNING COMMUTE. THEN THE DAY SHIFT
SHOULD BE ABLE TO CANCEL THEM EARLY...AROUND THE EARLY AFTERNOON
TIME FRAME. FINALLY...WILL REISSUE THE SPS FOR IRON/DICKINSON AND
ADD MENOMINEE COUNTY TO HIGHLIGHT THE STRONGER SNOW BAND THAT
STRETCHES ACROSS THOSE COUNTIES AND THE IMPACT IT WILL HAVE ON THE
MORNING COMMUTE.

WITH THAT DRY AIR SURGING INTO THE AREA AND A SURFACE HIGH SITUATED
OVER MINNESOTA AND NORTHWEST ONTARIO TONIGHT...EXPECT A GENERALLY
QUIET NIGHT ACROSS MUCH OF THE AREA. THERE CONTINUES TO BE SOME
INDICATION OF A POCKET OF LOW LEVEL MOISTURE REMAINING TRAPPED
BELOW THE SUBSIDENCE INVERSION FROM THE SURFACE HIGH (AROUND 900MB).
THESE POTENTIAL LOW CLOUDS WILL HAVE A SIGNIFICANT IMPACT ON
TEMPERATURES OVER THE NORTH CENTRAL AND INTERIOR WEST. THINK THE
BEST OPPORTUNITY FOR THE LOW CLOUDS WILL BE OVER THE HIGHER TERRAIN
OF THE NORTH CENTRAL WITH THE FAVORABLE UPSLOPE TERRAIN ENHANCEMENT
AND ALSO ALONG THE HIGHER GOGEBIC RANGE. WITH THE NORTH-NORTHEAST
WINDS...IT WILL TRY TO STRETCH OVER THE INTERIOR LOCATIONS AND WILL
HOLD ONTO MOSTLY CLOUDY SKIES IN THOSE LOCATIONS. WITH THAT
EXPECTATION...WILL KEEP LOWS IN THE TEENS OR AROUND 20 AND CLOSER
TO RAW MODEL GUIDANCE. IF THINGS CLEAR OUT MORE THAN EXPECTED LATE
THIS AFTERNOON AND EVENING...LOWS IN MANY LOCATIONS WOULD NEED TO
BE DROPPED A GOOD 10 DEGREES (INTO THE SINGLE DIGITS ABOVE ZERO)
THAN THE GOING FORECAST.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 507 AM EST WED DEC 17 2014

THURSDAY INTO THURSDAY NIGHT...EXPECT DRY WEATHER WITH MID LEVEL AND SFC
RIDGING INTO THE NRN LAKES. EVEN WITH LIGHT NORTH WINDS...850 MB
TEMPS AROUND -6C WILL PROVIDE LITTLE INSTABILITY FOR ANY LES
POTENTIAL. LAKE MOISTURE/CLOUDS MAY LINGER OVER THE WEST HALF INTO
THE AFTERNOON AND THEN THIN OUT LATE WITH LIMITED
MIXING...INCREASINGLY ACYC FLOW AND CONTINUED 925 MB NE FLOW DRY
ADVECTION.  HIGH PRESSURE OVER THE REGION AND PWAT VALUES DOWN TO
0.15 INCH WILL SUPPORT GOOD RADIATIONAL COOLING AND MIN TEMPS DOWN
TO THE LOWER END OF GUIDANCE. LOOK FOR READING AROUND 3F TO 8F
INLAND AND TEENS CLOSER TO THE GREAT LAKES.

FRI AND SAT...AS THE SFC HIGH SLOWLY BUILDS INTO THE ERN
LAKES...SRLY WINDS WILL BRING A GRADUAL WARMUP WITH TEMPS CLIMBING
SLIGHTLY ABOVE NORMAL. MAX READINGS IN THE UPPER 20S FRI WILL CLIMB
TO AROUND 30 SAT. AFTER SOME SUN ON FRI...CLOUDS WILL SPREAD BACK
TOWARD UPPER MI FRI NIGHT AND SAT...PER NAM/GFS 925-700 MB RH PROGS.
EVEN WITH THE SLIGHT INCREASE IN MOISTURE ANY VERY WEAK SHORTWAVES
NORTH OF THE MORE ACTIVE SRN STREAM ARE NOT EXPECTED TO SUPPORT ANY PCPN.

SUN-TUE...THE GFS/GEFS AND ECMWF WERE SIMILAR IN SUGGESTING THAT A
MORE ACTIVE PATTERN WILL RETURN AS A MID LEVEL TROUGH DEEPENS ACROSS
THE CENTRAL CONUS. THE DETAILS ON THE POSITION OF THE SFC FEATURES
AND HOW ANY SHORTWAVES WILL INTERACT THAT WOULD SUPPORT PCPN INTO
UPPER MI IS UNCERTAIN. PCPN CHANCES WILL INCREASE FROM MON INTO TUE
AS MORE SUBSTANTIAL MOISTURE ADVECTION DEVELOPS WITH STRONGER SRLY
FLOW AHEAD OF SFC LOW OR TROUGH. ALTHOUGH THE GFS BRINGS IN ENOUGH
WARM AIR FOR THE POTENTIAL FOR RAIN BY TUE...SINCE THE ECMWF KEEPS
THE WARMER AIR TO THE SOUTH...ONLY SNOW WAS MENTIONED FOR NOW.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1235 AM EST WED DEC 17 2014

IWD...ALTHOUGH SOME MID LVL DRYING ASSOCIATED WITH AN APRCHG UPR
DISTURBANCE IN MN HAS LIMITED SN INTENSITY...EXPECT SOME LK ENHANCED
SN/IFR CONDITIONS TO DEVELOP EARLY THIS MRNG AS THE DEEPER MSTR
SHIFTS TO THE S AGAIN IN THE PRESENCE OF AN UPSLOPE N WIND. BUT AS
THE DYNAMIC FORCING ASSOCIATED WITH THIS DISTURBANCE PULLS AWAY IN
THE MRNG AND DRIER LLVL AIR ADVECTS INTO THE AREA BY LATE IN THE
DAY...CONDITIONS WL IMPROVE TO MVFR AND THEN TO VFR LATE IN THE FCST
PERIOD.

CMX...EXPECT PERIODS OF LK ENHANCED SN/IFR VSBYS TO PERSIST INTO THE
MRNG. AS THE RESPONSIBLE UPR DISTURBANCE/ACCOMANYING DYNAMIC FORCING
DEPART BY LATE MRNG...CONDITIONS SHOULD IMPROVE TO MVFR. FURTHER
IMPROVEMENT TO VFR IS LIKELY IN THE EVNG WITH THE ARRIVAL OF DRIER
AIR/NEGLIGIBLE UPSLOPE WIND COMPONENT.

SAW...EXPECT SOME HEAVIER LK ENHANCED SN TO DEVELOP EARLY THIS MRNG
WITH AN UPSLOPE N WIND AND BRING PREDOMINANT IFR VSBYS FOR A TIME
UNTIL THE AFTN...WHEN THE EXIT OF THE SHRTWV/ASSOCIATED DYNAMIC
FORCING CAUSES THE PCPN TO DIMINISH AND CONDITIONS TO TRANSITION TO
MVFR. THE ARRIVAL OF DRIER AIR WL BRING VFR CONDITIONS BY LATE IN
THE TAF PERIOD.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 341 AM EST WED DEC 17 2014

A SURFACE LOW OVER SOUTHEAST ONTARIO WILL MOVE EAST TODAY...PULLING
THE 30.0 INCH TROUGH THAT IS STRETCHING WEST ACROSS LAKE SUPERIOR
EAST-SOUTHEAST WITH IT. NORTHERLY WINDS AROUND 25KTS ALONG THIS
TROUGH WILL CONTINUE THIS MORNING AND THEN GRADUALLY DIMINISH THIS
AFTERNOON AND TONIGHT AS A 30.3 INCH HIGH IN NORTHWEST ONTARIO
THROUGH THE EASTERN DAKOTAS MOVES INTO THE AREA. THIS HIGH WILL
SLOWLY MOVE ACROSS THE UPPER GREAT LAKES REGION THROUGH
FRIDAY...LEADING TO WINDS LESS THAN 20KTS. AS THE HIGH DEPARTS
FRIDAY NIGHT...SOUTHERLY WINDS WILL DEVELOP (BUT STILL BE BELOW
20KTS) AHEAD OF A BROAD TROUGH THAT WILL REMAIN STATIONARY THROUGH
THE WEEKEND JUST TO THE EAST OF THE CANADIAN AND NORTHERN ROCKIES.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
     MIZ005>007-085.

  WINTER STORM WARNING UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR
     MIZ002>004-009-084.

  WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ001.

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

$$

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






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