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000
FXUS63 KAPX 121759
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1259 PM EST THU DEC 12 2013

.SYNOPSIS...
ISSUED AT 436 AM EST THU DEC 12 2013

LAKE EFFECT SNOW SHOWERS WILL CONTINUE THROUGH EARLY FRIDAY. THERE
MAY BE A SHORT BREAK IN THE ACTION FRIDAY AFTERNOON INTO FRIDAY
NIGHT...THEN A SYSTEM MOVING ACROSS THE OHIO VALLEY...WILL LIKELY
GENERATE LIGHT SNOW ACROSS THE REGION THIS WEEKEND. TEMPERATURES
OVER THE NEXT SEVERAL DAYS WILL REMAIN WELL BELOW AVERAGE FOR MID
DECEMBER.

&&

.UPDATE...
ISSUED AT 1230 PM EST THU DEC 12 2013

SNOW BANDS ARE IN A WEST PATTERN AND WILL SHIFT TO A NW PATTERN
THROUGH THE AFTERNOON. WITH THE SHIFTING OF THESE BANDS, SOME
BANDS HAVE BEEN PUSHED TOGETHER TO PROVIDE EXTRA LIFT AND THEREBY
PRODUCING SOME HIGHER SNOW RATES. HOWEVER, AS STATED EARLIER,
THESE BANDS ARE MOVING SLOWLY TO REORIENT TO THE NEW WIND PATTERN.
THIS WILL CAUSE THE SNOW AMOUNTS TO BE 3-5 INCHES WITH LOCALLY
HIGHER AMOUNTS AS THESE BANDS MOVE THROUGH THE REGION.

THE LAKE SUPERIOR HAVE MADE IT ONSHORE AND THERE WILL BE SEVERAL
BANDS THAT WILL MOVE THROUGH THE WHITEFISH POINT/PARADISE AREA
THROUGH THE AFTERNOON. WILL BE MAKING SOME TWEAKS TO THE GRIDS TO
BRING THEM MORE IN LINE WITH THE CURRENT THINKING.

UPDATE ISSUED AT 943 AM EST THU DEC 12 2013

LAKE EFFECT SNOW BANDS ARE THE MAIN CONCERN THIS MORNING, AS WELL
AS RIVER ICE JAM FLOODING.

FLOODING...WHILE ALL RIVERS HAVE SHOWN SOME INDICATION OF
POTENTIAL ICE JAM FLOODING, ONLY THE MANISTEE NEAR SHERMAN IS
SHOWING ANY EVIDENCE OF IT. THE RIVER CAME UP DRASTICALLY
YESTERDAY, AND THEN LEVELED OFF. HOWEVER, JUST DOWNSTREAM FROM THE
GAGE, CLOSER TO MESICK THE RIVER HAS BEEN OVER THE BRIDGE ON 11 RD
BETWEEN 14 RD AND 16 RD. SO WILL KEEP THAT RIVER FLOODING GOING
FOR A WHILE AS THIS WILL PROBABLY CONTINUE THROUGH THE DAY AT THE
LEAST.

AS MENTIONED ABOVE, ALL RIVERS IN THE FORECAST AREA, HAVE THE
POTENTIAL OVER THE NEXT SEVERAL DAYS, AS THE TEMPERATURES CONTINUE
TO BE WELL BELOW FREEZING, AND HAVEN`T FROZEN OVER YET.

LAKE EFFECT SNOW...

E UPPER...UPSTREAM, OVER CENTRAL LAKE SUPERIOR, THE SNOW BANDS ARE
SHOWING A WEST-NORTHWEST ORIENTATION, WHICH WOULD PUT THE BAND
INTO WESTERN CHIPPEWA COUNTY, NEAR WHITEFISH POINT OVER THE NEXT
2-3 HOURS. HAVE ADJUSTED THE START TIME OF THE HEAVY SNOW MOVING
BACK INTO THAT AREA.

NW LOWER...THE WEST TO WEST-SOUTHWEST BANDS IN NW LOWER ARE
BEGINNING TO SEE AN INCREASE IN INTENSITY AS THE SYNOPTIC MOISTURE
ASSOCIATED WITH THE SFC TROUGH MOVING THROUGH THE UPPER GREAT
LAKES MOVES INTO THE FORECAST AREA. AT THIS TIME, THINGS LOOK
GOOD, BUT WILL RE-EVALUATE AMOUNTS AND LOCATIONS AS THE BANDS
CHANGE THROUGH THE AFTERNOON.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 436 AM EST THU DEC 12 2013

SYNOPSIS...MIDNIGHT SURFACE/COMPOSITE ANALYSIS SHOWS 1039MB ARCTIC
HIGH CENTERED OVER MISSOURI/SOUTHERN ILLINOIS...SUB-ZERO
TEMPERATURES ENCOMPASS THE UPPER MIDWEST AND THE UPPER PENINSULA.
WESTERLY FLOW LAKE EFFECT SNOW SHOWERS CONTINUE ACROSS NORTHWEST
LOWER MICHIGAN...WHILE SNOW SHOWERS OFF LAKE SUPERIOR HAVE MOSTLY
ENDED ACROSS EASTERN UPPER AS LOW LEVEL CONVERGENCE AXIS HAS SHIFTED
FARTHER OUT INTO THE LAKE AND PULLED THE CLOUDS AND PRECIPITATION
WITH IT.  WATER VAPOR IMAGERY SHOWS A QUICK MOVING SHORT WAVE MOVING
SOUTHEAST ACROSS NORTHERN WISCONSIN ALONG THE CYCLONIC SHEAR AXIS OF
A 150KT JET CORE ACROSS SOUTHERN MANITOBA/MINNESOTA.  SMALL POCKET
OF SNOWFALL WITH THIS FEATURE ACROSS NORTHWEST WISCONSIN/NORTHEAST
MINNESOTA...WHILE SPREADING MID/HIGH CLOUDS ACROSS THE REST OF
WISCONSIN/UPPER MICHIGAN.  LOW LEVEL THERMAL TROUGH REMAINS OVER THE
GREAT LAKES...00Z APX SOUNDING 850MB TEMPERATURE -21C WITH LOW/MID
LEVEL WARM ADVECTION OCCURRING ACROSS THE UPPER MIDWEST ATOP
BOUNDARY LAYER COLD DOME.

WISCONSIN SHORT WAVE TROUGH EXPECTED TO PUSH QUICKLY ACROSS CENTRAL/
SOUTHERN LOWER MICHIGAN TODAY...WITH ANOTHER SHEARED OUT VORTICITY
MAXIMUM ASSOCIATED WITH THE JET AXIS FORECAST TO PASS EAST OF
MICHIGAN TONIGHT.  THIS IS EXPECTED TO RESULT IN PRESSURE FALLS
ALONG THE ONTARIO/QUEBEC BORDER...AND WILL ENHANCE SURFACE TROUGHING
OVER THE UPPER LAKES TONIGHT.  SO SHORT TERM FORECAST CONCERNS WILL
CONTINUE TO REVOLVE AROUND EVOLUTION OF LAKE CONVECTION...AND ANY
IMPACTS FROM SHORT WAVE PASSAGE THIS MORNING.

TODAY/TONIGHT...EASTERN UPPER: EXPECTING A RELATIVELY QUIET START TO
THE DAY NORTH OF THE BRIDGE...WITH MID/HIGH CLOUDS OVER EASTERN
UPPER MICHIGAN THIS MORNING.  LAKE ENHANCED SNOW SHOWERS OFF LAKE
MICHIGAN/FAR NORTHERN LAKE HURON COULD CLIP THE STRAITS REGION AND
OVER TO DRUMMOND ISLAND WITH LOW LEVEL FLOW AROUND 250 DEGREES.
LAKE SUPERIOR SNOW SHOWERS SHOULD REMAIN NORTH OF WHITEFISH BAY THIS
MORNING...THEN AS WINDS START TO VEER MORE TO THE WEST-NORTHWEST
THIS AFTERNOON AND LOW LEVEL CONVERGENCE AXIS SHIFTS SOUTH WILL
ALLOW A SNOW BAND (LIKELY MODERATE-HEAVY) TO DRIFT BACK INTO
NORTHWEST CHIPPEWA COUNTY...PERHAPS GETTING VERY CLOSE TO THE SOO BY
EARLY EVENING.  GUSTY WINDS EXPECTED FROM THE WEST/SOUTHWEST
TODAY...20-25MPH GUSTS WITH SOME HIGHER NEAR THE LAKES.

PROBLEM FOR TONIGHT WILL BE WITH STRENGTHENING SURFACE TROUGH THAT
IS FORECAST TO PUSH SOUTH FROM LAKE SUPERIOR AND ACROSS UPPER
MICHIGAN...WITH MAY EVENTUALLY ALLOW A COLD NORTHEAST WIND TO PUSH
INTO FAR EASTERN UPPER BY FRIDAY MORNING.  THIS EVOLUTION SUGGESTS
THAT ANY DOMINANT SNOW BAND THAT SETS UP SHOULD BE TRANSIENT AND
PUSH SOUTH WITH THE BEST CONVERGENCE WITH TIME.  THIS SHOULD KEEP
SNOW TOTALS FROM GETTING OUT OF HAND IN THE WHITEFISH BAY
VICINITY...BUT DO THINK THAT ANOTHER LAKE SNOW HEADLINE (ADVISORY)
WILL EVENTUALLY BE NEEDED...WITH HEAVIER SNOW LIKELY PUSHING INTO
MORE POPULATED AREAS.  CURRENT FORECAST WILL HAVE A STRIPE OF 4-8
INCHES TONIGHT ALONG AND NORTH OF THE M-28 CORRIDOR...TAPERING TO
1-3 INCHES SOUTH (ASSUMING THAT A BRIEF PERIOD OF HIGHER SNOWFALL
RATES WILL EVENTUALLY PUSH INTO MACKINAC/SOUTHEAST CHIPPEWA
COUNTY).  SINCE WE`LL BE DROPPING THE OLD WARNING WITH FORECAST
ISSUANCE...WILL ALLOW FOR A BIT OF A "HEADLINE BREAK" FOR CHIPPEWA
COUNTY BEFORE HOISTING ANOTHER ONE.

NORTHERN LOWER: MOISTURE ASSOCIATED WITH UPSTREAM SHORT WAVE AND
LOW/MID LEVEL WARM ADVECTION SPREADING ACROSS CENTRAL INTO EASTERN
WISCONSIN EARLY THIS MORNING WITH SOME WEAK RADAR RETURNS.  AS THIS
MOISTURE OVERSPREADS LAKE MICHIGAN AROUND DAYBREAK EXPECT AN UPTICK
IN SNOW SHOWER ACTIVITY OFF THE LAKE WITH AT LEAST SOME SEEDER-
FEEDER TYPE OF ENHANCEMENT TO SNOW BANDS IN ADDITION TO THE
POTENTIAL FOR SOME LIGHT WARM ADVECTION/ISENTROPIC ASCENT SNOW OR
FLURRIES DEVELOPING.  ALTHOUGH SYNOPTIC CONTRIBUTION NOT
SUBSTANTIAL...THINK WE COULD GENERATE A COUPLE INCHES OF ENHANCED
SNOWFALL THIS MORNING ACROSS FAR NORTHWEST LOWER MICHIGAN (CENTERED
IN THE AREA FROM GRAND TRAVERSE TO LITTLE TRAVERSE BAY).  LOW LEVEL
FLOW WILL SHIFT FROM WEST-SOUTHWEST TO MORE WESTERLY THIS AFTERNOON
WITH PASSAGE OF SUBTLE 850MB TROUGH AXIS...THIS SHOULD FOCUS
ACTIVITY MORE ACROSS AREAS NORTH OF THE M-72 CORRIDOR AS THE
AFTERNOON PROGRESSES.  GUSTY WEST-SOUTHWEST WINDS EXPECTED TODAY ON
THE ORDER TO 20-25MPH GUSTS...AROUND 30MPH NEAR LAKE MICHIGAN.

LAKE SNOW SHOWERS WILL BE ONGOING ESPECIALLY NORTH OF THE M-72
CORRIDOR EARLY THIS EVENING...WITH A SURFACE TROUGH FROM LAKE
SUPERIOR EXPECTED TO DROP INTO NORTHERN LOWER OVERNIGHT. LOW LEVEL
WINDS ARE FORECAST TO GRADUALLY VEER WHICH SHOULD SPREAD SNOWFALL
OUT A BIT AND EVENTUALLY INCREASE SNOW SHOWERS SOUTH OF THE M-72
CORRIDOR. WILL KEEP ACCUMULATIONS TONIGHT ON THE LIGHT SIDE FOR
THE MOST PART...BUT ARRIVAL OF SURFACE TROUGH/CONVERGENCE AXIS MAY
DRAG A BAND OF HIGHER INTENSITY SNOWFALL DOWN ACROSS NORTHERN
LOWER AFTER MIDNIGHT...SO HAVE SOME SNOW ACCUMULATIONS ALL THE WAY
ACROSS NORTHEAST LOWER TO ACCOUNT FOR THIS.

HYDROLOGY...ICE ACTIVITY INCREASING ON AREA RIVERS...GETTING SOME
SIGNS OF JAMS DEVELOPING IN SPOTS. UNUSUALLY HIGH BASE FLOW DUE TO
THE WET FALL ALSO HAVING AN IMPACT. FLOOD WARNING FOR MANISTEE
RIVER NEAR SHERMAN WITH A FORECAST RISE ABOVE FLOOD STAGE...STAGE
JUMPED 2 FEET BETWEEN NOON AND MIDNIGHT BUT HAS SINCE LEVELED OFF.
NO WAY OF KNOWING WHETHER RIVER WILL EVENTUALLY BUMP ABOVE FLOOD
STAGE (15 FEET)...MUCH WILL DEPEND ON UPSTREAM FLOW AND
CHARACTERISTICS OF THE ICE BLOCKAGE.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 436 AM EST THU DEC 12 2013

THE OVERALL PATTERN OF STRONG EASTERN PACIFIC RIDGING FORCING
DOWNSTREAM TROUGHING ACROSS CENTRAL CANADA INTO THE GREAT LAKES
LOOKS LIKE IT WILL CONTINUE FOR THE MOST PART THROUGH THE EXTENDED
FORECAST PERIOD. THIS SHOULD LOCK IN UNSEASONABLY COLD TEMPERATURES
AND CHANCES FOR SNOW OVER THE COMING DAYS. THERE COULD BE A COUPLE
OF SHORT BREAKS IN THE ACTION...MAINLY FRIDAY INTO FRIDAY NIGHT AND
SUNDAY NIGHT INTO MONDAY AS ARCTIC HIGH PRESSURE TRIES TO
TEMPORARILY NOSE DOWN FROM THE NORTH. IN BETWEEN...THE COMBINATION
OF A FEW FACTORS...UPPER WAVES AND MILDER AIR ATTEMPTING TO RIDE UP
AND OVER THE ARCTIC AIR MASS IN PLACE (AND A SYSTEM MOVING BY TO OUR
SOUTH OVER THE WEEKEND) WILL LEAD TO VARIOUS CHANCES FOR MAINLY
LIGHT SNOW. HOWEVER...DEPENDING UPON THE FLOW REGIME...THERE COULD
BE SOME SNEAKY LAKE ENHANCEMENT WHICH WILL BE LEFT TO THE SHORTER
TERM DUE TO UNCERTAINTY OVER THE FINER DETAILS. OVERALL...THE ACTIVE
PATTERN WILL CONTINUE...ALONG WITH THE COLD TEMPERATURES OVER THE
NEXT SEVERAL DAYS AT A MINIMUM. THERE COULD EVENTUALLY BE A STRONGER
SYNOPTIC STORM SYSTEM LATE NEXT WEEK OR NEXT WEEKEND AS WE SIT IN
THE CROSS HAIRS OF A STRONG BAROCLINIC ZONE (THE BATTLE GROUND
BETWEEN THE ARCTIC AIR IN PLACE AND MILDER AIR TO THE SOUTH). THE
MAIN FORECAST CONCERNS REVOLVE AROUND POPS AND SNOWFALL
ACCUMULATIONS OVER THE NEXT FEW DAYS.

FRIDAY...LEFTOVER NORTHWEST FLOW LAKE EFFECT TO START THE DAY IS
EXPECTED TO BE OVERWHELMED BY A FAIRLY STRONG DRAINAGE FLOW FROM THE
NORTH AS ARCTIC HIGH PRESSURE NOSES DOWN. ADDITIONAL ACCUMULATIONS
ARE EXPECTED TO BE AN INCH OR LESS ACROSS EASTERN UPPER AND
NORTHWEST LOWER. MEANWHILE...THE FLOW REALLY LIGHTENS UP AND DRIER
AIR ADVECTS IN FROM THE NORTH SO DESPITE CONTINUED IMPRESSIVE OVER
LAKE INSTABILITY...ACTIVITY SHOULD HAVE A HARD TIME ORGANIZING AS
THE DAY WEARS ON. COLD ONCE AGAIN WITH HIGHS RANGING FROM THE MIDDLE
AND UPPER SINGLE DIGITS ACROSS EASTERN UPPER TO AROUND 20 SOUTH.

FRIDAY NIGHT...LOW PRESSURE DEVELOPS ACROSS THE TENNESSEE VALLEY AND
ADVECTS SOME MOISTURE UP FROM THE SOUTH INTO NORTHERN LOWER
MICHIGAN. MEANWHILE...AN EAST SOUTHEAST FLOW OFF OF LAKE HURON
DEVELOPS AND INCREASES AS THE NIGHT GOES ON. THIS IS EXPECTED TO
LEAD TO INCREASING CHANCES FOR SNOW SHOWERS...WITH POSSIBLE LAKE
ENHANCEMENT AS THE ARCTIC AIR REMAINS IN PLACE. RIGHT NOW ONLY HAVE
AROUND AN INCH OF ACCUMULATION NEAR LAKE HURON BUT COULD SEE MORE
DEPENDING UPON HOW FAST THINGS SET UP (BETTER CHANCE IS ON
SATURDAY). LOWS RANGING FROM THE SINGLE DIGITS ABOVE AND BELOW ZERO
NORTH TO THE MIDDLE TEENS ALONG THE SOUTHERN LAKESHORES.

SATURDAY INTO SUNDAY...LOW PRESSURE TRACKS BY WELL TO OUR SOUTHEAST
SATURDAY INTO SATURDAY NIGHT (BUT LOOKS LIKE IT TRANSPORTS SOME
MOISTURE FAIRLY FAR TO THE NORTHWEST INTO OUR NECK OF THE WOODS)
THEN A NORTHERN STREAM SHORT WAVE DROPS INTO THE REGION ON SUNDAY.
THIS SETUP WILL LEAD TO DECENT CHANCES FOR MORE MAINLY LIGHT
SNOW...THOUGH AM BECOMING INCREASINGLY CONCERNED ABOUT LAKE
ENHANCEMENT OFF OF LAKE HURON SATURDAY INTO SATURDAY EVENING. MOST
SPOTS ARE EXPECTED TO SEE AN INCH OR TWO OF ACCUMULATION BUT FAVORED
AREAS DOWNWIND OF LAKE HURON COULD END UP GETTING A FEW INCHES (OR
MORE)...BUT THERE IS PLENTY OF TIME TO REFINE THIS. TEMPERATURES ARE
EXPECTED TO REMAIN COLD WITH HIGHS RANGING FROM THE TEENS TO LOWER
20S AND LOWS RANGING FROM THE SINGLE DIGITS TO THE MIDDLE TEENS
SATURDAY NIGHT.

SUNDAY NIGHT THROUGH WEDNESDAY...IT LOOKS LIKE HIGH PRESSURE WILL
TRY TO NOSE INTO THE REGION TO START NEXT WEEK...THOUGH THE LAKE
EFFECT MACHINE MAY STILL BE RUNNING (WITH A MORE NORTHERLY COMPONENT
TO THE LAKE EFFECT BANDS). A DECENT LOOKING ALBERTA CLIPPER SYSTEM
LOOKS LIKE IT MAY BRING WARM ADVECTION DRIVEN SNOW MONDAY NIGHT THEN
RECHARGE LAKE EFFECT FOR TUESDAY INTO WEDNESDAY AS WELL AS BRING
ANOTHER SHOT OF MODIFIED ARCTIC AIR. AS MENTIONED ABOVE THERE WILL
BE INCREASING CHANCES FOR A SYNOPTIC STORM SYSTEM TO AFFECT THE
REGION LATER IN THE WEEK OR NEXT WEEKEND AS NORTHERN MICHIGAN LOOKS
TO BE IN A FAVORABLE LOCATION FOR DEVELOPMENT (STAY TUNED). LOWS
SUNDAY NIGHT RANGING FROM THE SINGLE DIGITS ABOVE AND BELOW ZERO.
HIGHS MONDAY RANGING FROM THE UPPER TEENS TO LOWER 20S THEN PERHAPS
THE MILDER MIDDLE TO UPPER 20S TUESDAY AND WEDNESDAY (WHICH IS STILL
A BIT BELOW MID DECEMBER AVERAGES). LOWS MONDAY NIGHT THROUGH
WEDNESDAY NIGHT MAINLY IN THE NOT AS COLD TEENS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1230 PM EST THU DEC 12 2013

SNOW BANDS...THAT`S THE MAIN ISSUE AT THIS POINT. AT PLN, THE WEST
BANDS HAVE BEEN PRODUCING IFR TO MVFR CONDITIONS, WILL CONTINUE TO
AS THE BANDS SHIFT.

AT TVC/MBL, THE SNOW BANDS WERE CAUSING MVFR AND IFR CONDITIONS
AND HAVE TAKEN A REPRIEVE. HOWEVER, AS THE BANDS COME AROUND
TOWARD THE NW LATER TONIGHT, THE CIGS AND VSBYS WILL FALL TO IFR
CATEGORIES.

AT APN, CONDITIONS SHOULD REMAIN VFR TO MVFR THROUGH THE DAY AS
THE BANDS DON`T SEEM STRONG ENOUGH AT THIS POINT TO MAKE IT ACROSS
THE STATE.

&&

.MARINE...
ISSUED AT 436 AM EST THU DEC 12 2013

WINDS WILL REMAIN GUSTY ON THE GREAT LAKES WITH CONTINUED LOW LEVEL
MIXING AND STRONGER WINDS WITHIN THE CONVECTIVE BOUNDARY LAYER.
NEEDLESS TO SAY SMALL CRAFT ADVISORIES WILL REMAIN IN EFFECT AND
WILL LIKELY BE EXTENDED IN TIME.  WINDS EXPECTED TO VEER MORE
NORTHWEST WITH TIME...AND LIKELY NORTH/NORTHEAST OVER WHITEFISH
BAY/ST. MARY`S RIVER TONIGHT AS A SURFACE TROUGH DROPS SOUTH ACROSS
THE FORECAST AREA.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ016-
     017-019-021-022.
LH...SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR LMZ323-341-342-
     344>346.
LS...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR LSZ322.
     SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR LSZ321.

&&

$$

UPDATE...JL
SYNOPSIS...AJS
SHORT TERM...JPB
LONG TERM...AJS
AVIATION...JL
MARINE...JPB