Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 231025
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
525 AM EST SUN NOV 23 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 523 AM EST SUN NOV 23 2014

MAIN FORECAST CONCERNS INCLUDE DENSE FOG THIS MORNING...TIMING THE
ONSET OF PCPN LATER TODAY AND THEN THE CHANGEOVER TO SNOW LATE
TONIGHT IN THE WEST.

WV IMAGERY AND RUC ANALYSIS SHOWS A VIGOROUS SRN STREAM SHORTWAVE
OFF THE TX GULF COAST WITH A STRONG SHORTWAVE AND ASSOC 150+ KNOT
250 MB JET MOVING OFF THE PAC NW INTO NRN NEVADA. ANOTHER SHORTWAVE
TROUGH WAS MOVING INTO WRN ND. AT THE SFC...SRLY FLOW PREVAILED FROM
THE GULF TOWARD THE UPPER MS VALLEY AND NRN GREAT LAKES REGION BTWN
HIGH PRES OVER THE MID ATLANTIC AND A 993 MB LOW OVER ND. WAA AND
LOW CLOUD COVER HAVE MAINTAINED TEMPS IN THE MID AND UPPER 30S
ACROSS UPPER MI EARLY THIS MORNING. THE WARM AIR MOVING OVER THE
MOSTLY SNOWPACKED GROUND HAS ALSO RESULTED IN DENSE FOG ACROSS MUCH
OF THE ERN TWO THIRDS OF UPPER MI THIS MORNING.

TODAY...EXPECT PCPN CHANCES TO GRADUALLY INCREASE THROUGH THE DAY AS
STRONG MOISTURE ADVECTION/TRANSPORT CONTINUES AND 850-700 MB FGEN
INCREASES. EXPECT THE BETTER CHANCE FOR RAIN OVER THE SOUTH CENTRAL
AND EAST IN PROXIMITY TO THE STRONGER DYNAMICS AND BEST MOISTURE. AS
THE MID-LVL DRY LAYER MOISTENS UP ANY DRIZZLE SHOULD CHANGE OVER TO
RAIN BY MID TO LATE AFTERNOON. EXPECT TEMPS WILL CLIMB ABOVE NORMAL
INTO THE LOW TO MID 40S. WARM AIR MOVING OVER THE COLD SNOW PACK HAS
RESULTED IN DENSE FOG THIS MORNING SO HAVE POSTED A DENSE FOG
ADVISORY THROUGH 16Z FOR ALL BUT THE FAR FOUR WESTERN COUNTIES OF
THE CWA.

TONIGHT...CONTINUED INCREASE IN DEEP LAYER Q-VECT
CONVERGENCE...DEVELOPMENT OF COUPLED UPPER JET STRUCTURE AND
ENHANCED 850-700 MB FGEN WILL LEAD TO WIDESPREAD RAINFALL ACROSS
MUCH OF THE CWA BY EVENING. MODEL AVERAGED QPF RANGES FROM .25 WEST
TO .75 SOUTHEAST. MODEL SNDGS AND CRITICAL 1000-850 MB THICKNESSES
SUGGEST RAIN WILL BEGIN TO SWITCH OVER TO SNOW FAR WEST AROUND 09Z
BUT WITH SNOW/WATER RATIOS RISING TO ONLY AROUND 6-7/1 BY 12Z MON
EXPECT SNOW ACCUMULATION TO BE LESS THAN AN INCH FOR THE FAR WEST BY
12Z MONDAY. THERE IS POTENTIAL FOR FOG TO BE AN ISSUE WITH RAIN OVER
THE SNOWPACK SO THIS WILL BE SOMETHING TO WATCH LATER TODAY. TEMPS WILL
RANGE FM THE LOWER 30S WEST TO UPPER 30S EAST.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 426 PM EST SAT NOV 22 2014

QUITE AN ACTIVE START TO THE PERIOD AS THE PHASING OF NORTHERN AND
SOUTHERN ENERGY WILL BE UNDERWAY ACROSS THE UPPER GREAT LAKES.
MODERATE RAINFALL SUNDAY NIGHT WILL GIVE WAY TO A TRANSITION TO SNOW
ON MONDAY AS THE SYSTEM MOVES NE OF THE REGION. THE INGREDIENTS ARE
STILL THERE FOR MODERATE TO POSSIBLY HEAVY SNOW ACROSS AT LEAST THE
WESTERN CWA MONDAY AFTERNOON AND NIGHT. AFTER A REPRIEVE LATE
TUESDAY...A CLIPPER SYSTEM LOOKS TO BRING LIGHT TO POSSIBLY MODERATE
SNOWFALL WEDNESDAY AFTERNOON INTO THANKSGIVING.

SUNDAY NIGHT THROUGH MONDAY NIGHT...FIRST A LOOK AT THE OVERALL
SYNOPTIC PATTERN. TWO POTENT MID-LEVEL SHORTWAVES...ONE TRACKING
EASTWARD OVER THE NORTHERN PLAINS AND THE OTHER MOVING NORTHEASTWARD
NEAR SOUTHERN IL AT 00Z MONDAY WILL BEGIN TO MERGE ACROSS THE UPPER
GREAT LAKES. THE NORTHERN STREAM IS A BIT SLOWER REACHING THE REGION
THAN THE SOUTHERN STREAM...RESULTING IN A BROADENING OF THE TROUGH
BY MONDAY MORNING. MEANWHILE...A DEVELOPING MODEST COUPLED JET
PATTERN WILL DEVELOP OVER THE UPPER GREAT LAKES. THE SOUTHERN WAVE
WILL BE OF MOST INTEREST INITIALLY AS IT INDUCES A RAPIDLY DEEPENING
LOW OVER ILLINOIS AT THE START OF THE PERIOD. WITH THE 12/18Z NAM
RUNS COMING INTO BETTER AGREEMENT WITH THE OTHER MODELS...CONFIDENCE
IS NOW HIGHER REGARDING THE OVERALL EVOLUTION OF THE SYSTEM. THE SFC
LOW IS PROGGED TO TRACK NEAR THE STRAITS OF MACKINAC AROUND 12Z
MONDAY. THE GEM/NAM/ECMWF HINT AT A SLIGHT DEVIATION TO THE LEFT/NW
MONDAY MORNING...WITH THE LOW CROSSING NEAR SAULT STE MARIE. THIS
LOOKS REASONABLE AS THE INFLUENCE OF THE NORTHERN TROUGH APPROACHES.
A LINGERING TROUGH WILL THEN REMAIN ACROSS UPPER MI ON MONDAY AS THE
MID-LEVEL TROUGH AXIS REACHES THE REGION AND THE SFC LOW MOVES TO
JUST SE OF JAMES BAY.

NOW A LOOK AT THE OVERALL PRECIP TYPE AND INTENSITY. MID/UPPER-LEVEL
DYNAMICS AND LOW-LEVEL THERMODYNAMICS SUPPORT MODERATE RAIN ACROSS
MAINLY CENTRAL AND EASTERN UPPER MI SUNDAY NIGHT. THE RIGHT ENTRANCE
OF A DEVELOPING...ALBEIT ANTICYCLONICALLY CURVED...UPPER JET WILL
MAXIMIZE UPPER DIVERGENCE OVER CENTRAL AND EASTERN UPPER MI WHILE
MID-LEVEL Q-VECTOR CONVERGENCE PEAKS OVER NORTHERN LOWER MI.
MEANWHILE...LOW-LEVEL MOISTURE TRANSPORT WILL BE RATHER IMPRESSIVE
ACROSS THE EASTERN CWA...THEN QUICKLY DIMINISH TOWARD THE WESTERN
CWA. A SUFFICIENTLY DEEP LOW-LEVEL WARM LAYER WILL KEEP PRECIP ALL
RAIN ACROSS THE CWA...THOUGH A TRANSITION TO SNOW WILL BE UNDERWAY
LATE SUNDAY NIGHT ACROSS THE WEST AS CAA BEGINS BEHIND THE LOW. ALL
THIS TOGETHER FAVORS MODERATE RAIN ACROSS THE EAST HALF SUNDAY
NIGHT...WITH AN INITIALLY SHARP CUTOFF TO THE WEST BEFORE THE
NORTHERN WAVE APPROACHES OVERNIGHT.

CAA TAKING HOLD ON MONDAY WILL QUICKLY TRANSITION THE RAIN TO SNOW
FROM WEST TO EAST THROUGHOUT THE DAY. THERE ARE SOME INDICATIONS
THAT A LOW-LEVEL WARM LAYER MAY TRY TO WRAP AROUND THE BACK SIDE OF
THE LOW LATE MORNING MORNING INTO THE AFTERNOON. SOME SLEET MAY MIX
IN WITH THE RAIN/SNOW...BUT THE TRANSITION FROM ALL RAIN SNOW SHOULD
NOT TAKE MORE THAN AN HOUR OR TWO. THINK THAT EVEN THE SHORELINE
LOCATIONS SHOULD TRANSITION QUICKLY GIVEN THEN COLDER THAN AVERAGE
LAKE TEMPS. TRANSITION TIMES LOOK TO BE AROUND 09Z FOR IWD...12Z FOR
A LINE FROM HOUGHTON TO IRON RIVER...AND 15Z FOR A LINE FROM
MARQUETTE TO IMT. BY 21Z...ALL BUT POSSIBLY LUCE COUNTY SHOULD
TRANSITION TO SNOW.

A FAIRLY IMPRESSIVE MID-LEVEL FGEN/DEFORMATION ZONE WILL SET UP OVER
THE WESTERN CWA BY MONDAY AFTERNOON. WITH SOME SNOWFLAKE FRACTURING
FROM THE HIGHER WINDS AND THE MAX LIFT INITIALLY OCCURRING AT TEMPS
JUST A BIT WARMER THAN THE DGZ...SNOW RATIOS MAY REMAIN LOW /10 TO
1/ THROUGH MONDAY MORNING. AS TEMPS CONTINUE TO FALL IN TO THE
AFTERNOON SNOW RATIOS WILL BE ON THE RISE ACROSS THE WEST. LOW-LEVEL
WINDS AVERAGING OUT THE NORTH COMBINED WITH LAKE-850MB DELTA TEMPS
SURPASSING 10C SUPPORT DECENT LAKE-ENHANCEMENT FOR THE NORTH WIND
SNOW BELTS THROUGHOUT MONDAY. THIS PATTERN WILL CONTINUE INTO MONDAY
EVENING AS THE CONSOLIDATED TROUGH SLOWS OVER THE AREA AND KEEPS A
SFC TROUGH EXTENDED ACROSS MUCH OF EASTERN UPPER MI. ON TOP OF THE
SNOW...THE CAA WITH A STRONG WNW TO ESE ISALLOBARIC COMPONENT FROM
THE RAPIDLY DEEPENING LOW WILL YIELD A QUICK INCREASE IN WIND FROM
THE N/NNW.

WHEN ALL IS SAID AND DONE...SNOWFALL MONDAY AND MONDAY NIGHT IS
EXPECTED TO BE 6 TO 10 INCHES BASICALLY NORTH OF M-28 AND WEST OF
MARQUETTE. ELSEWHERE ACROSS THE CWA...2-4 INCHES IS EXPECTED.
HOWEVER...HIGHER AMOUNTS OF UP TO 6 INCHES WILL BE POSSIBLE FOR THE
NNW WIND SNOW BELTS FROM SHOT POINT TO GRAND MARAIS. THREW AROUND
THE IDEA OF A WINTER STORM WATCH FOR THE NW HALF...BUT DECIDED
AGAINST IT GIVEN SOME DETAILS IN QPF AND PLACEMENT OF FORCING THAT
NEED TO BE IRONED OUT. HOWEVER...WINTER WX ADVISORY CRITERIA SHOULD
BE MET. HAVE OPTED TO ISSUE A SPECIAL WX STATEMENT AT THIS TIME TO
HIGHLIGHT THE POTENTIAL...BUT ALSO NOTE THE UNCERTAINTY IN AMOUNTS.
MAIN IMPACTS WILL BE RATHER SLUSHY ROADS IN THE AFTERNOON FOLLOWED
BY BLOWING AND DRIFTING OF THE SNOW OVERNIGHT AS SNOW RATIOS
INCREASE.

TUESDAY THROUGH WEDNESDAY NIGHT...WEAK MID-LEVEL RIDGING...LOW-LEVEL
WAA AND INVERSION HEIGHTS FALLING BELOW 3KFT WILL PUT A QUICK END TO
THE LES FROM WEST TO EAST THROUGHOUT THE DAY. A CLIPPER SHORTWAVE
WILL TRACK SE INTO THE UPPER MS VALLEY LATE TUESDAY. THE SHORTWAVE
LOOKS TO GET CAUGHT UP IN A LARGER-SCALE TROUGH OVER HUDSON
BAY...ULTIMATELY SLOWING ITS PROGRESSING AND SHIFTING IT TO A ENE
TRACK. WHERE THIS TAKES PLACE WILL BE CRUCIAL FOR DETERMINING SNOW
PROBABILITY/AMOUNTS FOR THE CWA. THE GFS IS THE FASTEST...BRINGING
WIDESPREAD ACCUMULATING SNOW TO THE AREA LATE TUESDAY NIGHT INTO
WEDNESDAY AFTERNOON. THE ECMWF TAKES AN INITIALLY MORE AGGRESSIVE
EVOLUTION...RESULTING THE THE TROUGH DIGGING FARTHER SOUTHEAST
BEFORE PIVOTING ACROSS SOUTHERN LAKE/LOWER MI. WITH THIS
SCENARIO...MOST OF THE SNOW HOLDS OFF UNTIL WEDNESDAY NIGHT. THE GEM
FOLLOWS A SOLUTION IN THE MIDDLE...BUT LEANS MORE IN LINE WITH THE
GFS. ATTM...CANNOT REALLY PIN DOWN AMOUNTS AND EXACT TIMING...THOUGH
THE PROSPECTS FOR SEVERAL INCHES OF ACCUMULATING SNOW SOMETIME LATE
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT ARE GROWING.

THANKSGIVING...DEPENDING ON WHAT MODEL SOLUTION PANS
OUT...WIDESPREAD SNOW MAY LINGER THROUGH THE MORNING OR END BEFORE
DAYBREAK. EITHER WAY...CAA BEHIND THE CLIPPER SHOULD YIELD LES FOR
THE N/NNW WIND BELTS DURING THE DAY. IT STILL LOOKS COLD...WITH
TEMPS MORE IN LINE WITH CHRISTMAS RATHER THAN THANKSGIVING.
HOWEVER...WITH THE SLOWER SOLUTION...THE ECMWF HAS A HARDER TIME
BRINGING THE COLDEST AIR INTO THE REGION.

FRIDAY AND SATURDAY...LONG RANGE MODELS HAVE BACKED OFF SOMEWHERE ON
A TRANSITION TO A MORE ZONAL AND MILD PATTERN BEGINNING FRIDAY AND
DELAY IT UNTIL LATE IN THE WEEKEND. THE OVERALL PATTERN LOOKS QUIET
BESIDE SOME LES FOR THE WNW WIND SNOW BELTS.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 112 AM EST SUN NOV 23 2014

MOISTURE CONTINUING TO FLOW INTO THE AREA SHOULD RESULT IN LOWERING
OF CIGS FALLING TO LIFR LATE TONIGHT AS THE MOIST LOW-LEVELS WILL BE
ONLY BE AIDED BY ADDITIONAL MOISTURE AND HELPED ALONG BY DEVELOPING
UPSLOPE FLOW AT KCMX AND KSAW. THESE SITES WILL PROBABLY SEE DRIZZLE
AND FOG AS WELL WITH VSBY LIKELY REACHING IFR LATE TONIGHT.
CONDITIONS WILL STAY LIFR/VLIFR THROUGH THE REST OF THE FORECAST
PERIOD AT ALL SITES.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 523 AM EST SUN NOV 23 2014

SOUTH WINDS WILL INCREASE ON SUNDAY...ESPECIALLY OVER EASTERN
SECTIONS...BUT SHOULD REMAIN 30 KTS OR LESS. WINDS WILL BE VARIABLE
SUNDAY NIGHT AS TROUGH CROSSES LAKE SUPERIOR. A DEEPENING LOW WILL
MOVE TO EAST OF LAKE SUPERIOR ON MONDAY. NORTHERLY WINDS WILL
INCREASE TO GALES 40-45 KTS BY MONDAY MORNING INTO MONDAY NIGHT.
EXPECT WINDS TO DIMINISH TO 25 KTS OR LESS TUESDAY INTO
WEDNESDAY...THEN INCREASE TO 30 KTS ON THURSDAY AS COLD AIR POURS
ACROSS LAKE SUPERIOR BETWEEN HIGH PRESSURE BUILDING OVER THE
NORTHERN PLAINS AND LOW PRESSURE CROSSING THE LOWER GREAT LAKES.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  DENSE FOG ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR
     MIZ004>007-010>014-085.

LAKE SUPERIOR...
  GALE WARNING FROM 3 PM MONDAY TO 4 AM EST TUESDAY FOR LSZ251-267.

  GALE WARNING FROM 10 AM MONDAY TO 4 AM EST TUESDAY FOR
     LSZ246>250-265-266.

  GALE WARNING FROM 6 AM MONDAY TO 2 AM EST TUESDAY FOR LSZ242>245-
     263-264.

  GALE WARNING FROM NOON EST /11 AM CST/ TO 9 PM EST /8 PM CST/
     MONDAY FOR LSZ162.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...VOSS
LONG TERM...KLUBER
AVIATION...07
MARINE...VOSS






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