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000
FXUS63 KAPX 070402
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1102 PM EST FRI DEC 6 2013

.SYNOPSIS...
ISSUED AT 401 PM EST FRI DEC 6 2013

COLDER AIR WILL CONTINUE TO SPILL ACROSS THE GREAT LAKES THROUGH
SATURDAY...BRINGING MAINLY LIGHT LAKE EFFECT SNOW SHOWERS. MORE
WIDESPREAD LIGHT SNOW IS EXPECTED SUNDAY NIGHT INTO THE FIRST HALF
OF MONDAY...AS WEAK LOW PRESSURE SNEAKS THROUGH THE REGION. THAT
SYSTEM WILL USHER IN EVEN COLDER AIR FOR MUCH OF NEXT WEEK...ALONG
WITH BETTER CHANCES FOR ACCUMULATING LAKE EFFECT SNOWS.

&&

.UPDATE...
ISSUED AT 1100 PM EST FRI DEC 6 2013

HEAVIER LAKE EFFECT SNOW BANDS HAVE REORGANIZED INTO ANTRIM AND
OTSEGO COUNTIES LATE THIS EVENING...WITH ADDITIONAL WEAKER BANDS
EXTENDING NORTH AND SOUTH ON EITHER SIDE OF THE MAIN BAND.
DOMINANT HEAVY BAND OF SNOW SHOWERS CONTINUES TO TARGET FAR NRN
CHIPPEWA COUNTY NORTH OF M-28...SPECIFICALLY AROUND PARADISE AND
POINTS NORTH. WILL CERTAINLY KEEP THE LAKE SNOW ADVISORY IN TACT
FOR THIS AREA THRU THE NIGHT. FOR NW LWR MICHIGAN...HAVE SEEN A
MINOR UPTICK IN SNOWFALL INTENSITIES...BUT STILL WELL BELOW
ADVISORY CRITERIA. WILL LIKELY SEE SOME ADDITIONAL...ALBEIT
MINOR...INCREASE IN INTENSITY OVERNIGHT AS INVERSION HEIGHTS CLIMB
TO AROUND 7 KFT. STILL EXPECT A NIGHTTIME TOTAL OF 1 TO 2 INCHES
OF NEW SNOW FOR THIS AREA...WITH A FEW LOCALLY HIGHER AMOUNTS
POSSIBLE AS IS TYPICAL WITH LAKE EFFECT SNOW.


UPDATE ISSUED AT 700 PM EST FRI DEC 6 2013

W/NW FLOW LAKE EFFECT SNOW SHOWERS CONTINUE THIS EVENING. DOMINANT
HEAVY SNOW BAND CONTINUES TO STREAM INTO FAR NRN CHIPPEWA COUNTY
OFF OF LAKE SUPERIOR...WHERE SNOWFALL RATES ARE LIKELY ON THE
ORDER OF 1 TO 2 INCHES PER HOUR. SOUTH OF THE STRAITS...HEAVIEST
BAND IS FALL ACROSS SRN EMMET AND SRN CHEBOYGAN COUNTIES. AREAL
COVERAGE IS SLOWLY TRANSITIONING TO MORE WELL- DEFINED BANDING AS
IS TYPICAL AFTER SUNSET. EXPECT BANDS ACROSS ANTRIM...CHARLEVOIX
AND OTSEGO WILL BECOME MORE ORGANIZED THRU THE EVENING HOURS AS IS
TYPICAL OF A 280-290 DEGREE LOW LEVEL FLOW. ALSO...INVERSION
HEIGHTS WILL GRADUALLY LIFT TO AROUND 7 KFT ACROSS NRN LWR
MICHIGAN THROUGHOUT THE NIGHT...RESULTING IN DEEPER CONVECTION
AND THUS BETTER SNOWFALL RATES AS THE NIGHT PROGRESSES. STILL...
AIRMASS IS QUITE DRY ABOVE THE INVERSION...AND THIS WILL LIMIT
SNOWFALL TO 1 TO 3 INCHES ACROSS NW AND FAR NRN LWR MICHIGAN.

WILL CERTAINLY MAINTAIN THE LAKE EFFECT SNOW ADVISORY FOR CHIPPEWA
COUNTY...SPECIFICALLY FAR NRN CHIPPEWA NORTH OF M-28 WITH THE
HEAVIEST SNOW FALLING AROUND AND NORTH OF PARADISE. SNOWFALL
AMOUNTS FOR THE NIGHT WILL RANGE FROM LESS THAN INCH SOUTH OF M-28
TO AS MUCH AS 6-9 INCHES AROUND WHITEFISH POINT.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 401 PM EST FRI DEC 6 2013

A BIT OF A CHALLENGING LAKE EFFECT FORECAST FOR A TINY PORTION OF
THE AREA OVERNIGHT...WHILE MUCH OF THE REMAINDER OF THE AREA JUST
SITS IN RATHER STATUS QUO CONDITIONS TYPICAL OF EARLY DECEMBER -
THAT IS...COLD WITH FLURRIES/LIGHT SNOW SHOWERS. THE AREA OF CONCERN
OVERNIGHT AND INTO SATURDAY IS FAR NORTHERN CHIPPEWA COUNTY...MAINLY
UP TOWARD WHITEFISH POINT AND PARADISE...WHERE THE POTENTIAL EXISTS
FOR WHAT COULD BE SOME VERY HEAVY LOCALIZED AMOUNTS. THE BASIC SETUP
AT THE MOMENT CONSISTS OF LOW PRESSURE NEAR NORTHERN JAMES
BAY...WHILE A FAIRLY STRONG AREA OF ARCTIC HIGH PRESSURE IS NOSING
ITS WAY DOWN THE PLAINS STATES...WITH SOME DOWNRIGHT IMPRESSIVELY
CHILLY READINGS STILL WELL BELOW ZERO ACROSS PARTS OF ND/MT EVEN AT
MIDDAY! THE BASIC FLOW REGIME IN BETWEEN THESE TWO FEATURES
CONTINUES TO BE WEST/NORTHWESTERLY...WITH A NICE THERMAL TROUGH
RESPONSE NOTED IN THIS FLOW OVER EASTERN LAKE SUPERIOR...CLEARLY
EVIDENT THIS AFTERNOON BY BACKED FLOW OVER THE EASTERN U.P. AND
HEALTHY RADAR RETURNS JUST SCRAPING FAR NORTHERN CHIPPEWA COUNTY.
MEANWHILE...WIDESPREAD LIGHTER/FLUFFY SNOW SHOWERS AND FLURRIES
CONTINUE TO POUR OFF LAKE MICHIGAN...BUT AREN`T ADDING UP A WHOLE
LOT GIVEN TRANSIENT DIFFUSE BANDING (LOCALIZED AMOUNTS OF 1-2"
ESTIMATED VIA RADAR).

HEADING INTO TONIGHT...EXPECT THINGS WILL REMAIN FAIRLY CONSTANT
OVER NORTHERN LOWER...WITH LOTS OF MAINLY LIGHT SNOW SHOWERS...
PROBABLY DEVOLVING FROM BANDING INTO JUST A LARGER AREA OF LIGHTER
SNOWS AS THE BACKGROUND FLOW WEAKENS. THAT SAID...CAN`T COMPLETELY
RULE OUT SOME LOCALIZED HEAVIER AMOUNTS TARGETING PARTS OF
OTSEGO/ANTRIM COUNTIES WHERE THE W/NW FLOW WILL GET A BIT OF A BOOST
OFF GREEN BAY...ALL WHILE INVERSION HEIGHTS ARE PROGGED TO GRADUALLY
CLIMB UP ABOVE 800MB (FAR ABOVE THE CURRENT 875MB WE HAVE HAD
TODAY). THE THERMAL REGIME REMAINS ABOUT AS PERFECT AS IT CAN
BE...WITH THE MAJORITY OF THE CLOUD SQUARELY IN THE DGZ...SO RATIOS
WILL TEND TO RUN IN THE 30-50 TO 1 RANGE...JUST LIKE WE HAVE SEEN
THE PAST 24 HOURS. OVERALL...AMOUNTS IN THE TRACE-1" RANGE WILL
PROBABLY DO IT...THOUGH WILL CONTINUE TO PAINT SOME BETTER SNOWS
INTO THE TERRAIN...WITH PERHAPS 2-4" FALLING THROUGH SATURDAY IF ANY
WEAKER BANDS GET GOING.

THE BETTER FOCUS IS UP ACROSS NORTHERN CHIPPEWA COUNTY...WHERE ALL
TRENDS SEEMINGLY POINT TO THE CURRENT STRONG BAND BASICALLY HANGING
TIGHT NEAR PARADISE. THAT IDEA HAS MERIT AS A COLD FRONT DROPS
THROUGH ONTARIO...HELPING REINFORCE BROAD LOW LEVEL CYCLONIC FLOW
ACROSS EASTERN LAKE SUPERIOR...AND LIKELY MAINTAINING THE BEST
CONVERGENCE RIGHT NEAR THE LAKESHORE. THAT IS A BIT TROUBLING AS
FORECAST SOUNDINGS ARE OFF THE CHART FROM A LAKE SNOW PERSPECTIVE...
AS INVERSION HEIGHTS CLIMB UPWARD OF 700MB IN A VERY COLD AIR MASS...
WITH TREMENDOUS OMEGA BISECTING A QUITE DEEP DGZ. GIVEN THE RATIOS
ALREADY SEEN TODAY...HAVE TO BELIEVE SOME BIG TOTALS (MORE THAN A
FOOT?) ARE POSSIBLE...PROVIDED THE BAND DOESN`T MOVE - AND THAT OF
COURSE IS THE BIG UNKNOWN. BUT WILL ISSUE AN ADVISORY EVEN THOUGH
THE AMOUNT OF COUNTY COVERAGE OF HEAVY SNOWFALL SHOULD BE
INCREDIBLY LOW (GENERALLY ONLY ABOUT 5%).

TEMPS AREAWIDE TO REMAIN CHILLY...WITH LOWS TONIGHT MAINLY UPPER
SINGLE DIGITS TO TEENS...AND HIGHS SATURDAY TEENS TO LOWER 20S.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 401 PM EST FRI DEC 6 2013

SYNOPSIS...FULL LATITUDE LONG WAVE TROUGH ENCOMPASSES MUCH OF NORTH
AMERICA...WITH A STRENGTHENING BLOCKING RIDGE (-EPO) OVER THE GULF
OF ALASKA.  SEVERAL SHORT WAVE TROUGHS MOVING THROUGH THE MEAN LONG
WAVE POSITION...ONE COMING OUT OF THE CENTRAL ROCKIES INTO THE
CENTRAL/SOUTHERN PLAINS...A SECOND DIGGING SOUTH ALONG THE
WASHINGTON/OREGON COAST...AND A THIRD OVER THE HIGH ARCTIC WEST OF
THE DATELINE DROPPING INTO THE NORTHWEST TERRITORIES AS CROSS POLAR
FLOW DEVELOPS INTO NORTHWEST CANADA.  COLD AIR MASS CONTINUES TO
SPREAD INTO THE EASTERN CONUS...AS SUB-ZERO COLD ENCOMPASSES THE
NORTHER/CENTRAL ROCKIES EAST ACROSS ADJACENT PLAINS AND INTO THE
UPPER MIDWEST.

LONG WAVE TROUGH WILL BE REINFORCED BY LATTER SHORT WAVES MENTIONED
ABOVE...PACIFIC WAVE DIGS INTO THE GREAT BASIN AND CENTRAL ROCKIES
THIS WEEKEND WHILE ARCTIC WAVE HEADS TOWARD THE CANADIAN PRAIRIES.
EVENTUALLY THE ROCKIES ENERGY SHEARS NORTHEAST AND ACROSS THE GREAT
LAKES MONDAY WHILE ARCTIC WAVE AND SUB-500DM THICKNESSES INVADED THE
NORTHERN PLAINS/UPPER MIDWEST.  THAT NEXT REINFORCING PUSH OF COLD
AIR EXPECTED TO SWING THROUGH MICHIGAN LATER MONDAY INTO TUESDAY...
WHICH KEEPS NORTHERN MICHIGAN IN THE DEEP FREEZE THROUGH MIDWEEK.

ARCTIC HIGH PRESSURE EXTENDING FROM THE YUKON ALL THE WAY DOWN INTO
TEXAS THIS AFTERNOON WILL BUILD EAST THIS WEEKEND...AND ACROSS THE
GREAT LAKES SUNDAY.  ROCKIES SHORT WAVE LIFTING OUT TOWARD THE UPPER
LAKES WILL SPIN UP A WEAK SURFACE LOW THAT IS FORECAST TO CROSS
MICHIGAN MONDAY...LIKELY FOLLOWED BY AN "ARCTIC CLIPPER" ON
TUESDAY.  EACH OF THESE SYSTEMS WILL REINFORCE THE MAGNITUDE OF THE
COLD AIR MASS ACROSS MICHIGAN (COULD SINGLE DIGIT HIGHS BE IN THE
OFFING BY WEDNESDAY?).  WESTERLY BOUNDARY LAYER FLOW FORECAST TO
PERSIST THROUGH MIDWEEK...THEN MAY BEGIN TO MODERATE TEMPERATURES BY
THE END OF THE WEEK (AT LEAST TEMPORARILY) AS COLD HIGH PRESSURE
MOVES INTO THE MID ATLANTIC AND SOUTHERLY WINDS/WARM ADVECTION
DEVELOPS FRIDAY (THOUGH ANOTHER ARCTIC FRONT MAY BE LURKING FOR NEXT
WEEKEND).

SATURDAY NIGHT THROUGH MONDAY...MAIN FORECAST ISSUES IN THE NEAR
TERM WILL BE DEVELOPMENT OF SYNOPTIC SNOWFALL DRIVEN BY WARM
ADVECTION/ISENTROPIC ASCENT AND SHEARING SHORT WAVE TROUGH LIFTING
NORTHEAST FROM THE CENTRAL PLAINS.  HIGH PRESSURE WILL BE BUILDING
EAST ACROSS MICHIGAN SATURDAY NIGHT...WESTERLY BOUNDARY LAYER FLOW
SATURDAY EVENING WILL FOCUS CONTINUED SNOW SHOWER ACTIVITY NORTH OF
M-72 IN NORTHERN LOWER AND THE NORTHWEST CORNER OF CHIPPEWA COUNTY
IN THE UPPER PENINSULA.  QUESTION ACROSS CHIPPEWA COUNTY IS WHERE
STRONGEST BAND WILL BE LOCATED BY THIS TIME...CURRENT EXPECTATION IS
THAT IT MAY GET PUSHED FARTHER OUT INTO THE LAKE BY SATURDAY EVENING
BUT WILL BE VERY CLOSE BY SO NOT OUT OF THE QUESTION THAT DECENT
SNOWFALL MAY STILL CLIP THE WHITEFISH POINT VICINITY BUT NO WAY OF
KNOWING THAT 36+ HOURS OUT (THE OLD "SNOW FLASH FLOOD" ARGUMENT).
SNOW SHOWERS ACROSS NORTHERN LOWER WILL PROBABLY PERSIST BUT SHOULD
START TO TAPER OFF TO FLURRIES HEADING INTO SUNDAY MORNING.
MEANWHILE...LOW/MID LEVEL WARM ADVECTION PATTERN SETTING UP BY
SUNDAY ACROSS THE NATION`S MIDSECTION AND INTO THE UPPER LAKES
SUNDAY.  MID LEVEL MOISTURE WILL ARRIVE DURING THE DAY...LOW LAYERS
WILL TAKE SOME TIME TO MOISTEN SO MORE WIDESPREAD SNOWFALL WILL HOLD
OFF UNTIL LATER IN THE DAY...POSSIBLY BY EVENING THOUGH NAM/GFS
SHOWING POSSIBILITY OF ENOUGH SATURATION FOR SNOW LATE IN THE EVEN
THOUGH THIS NOT REFLECTED IN QPF (IT IS REFLECTED IN ECWMF/GGEM
QPF...MODEL SIGNALS VERSUS MODEL SOLUTIONS).  REGARDLESS OF
TIMING...WIDESPREAD SNOWFALL LOOKING TO BE A PRETTY GOOD BET SUNDAY
NIGHT AS WARM ADVECTION IS AUGMENTED BY WEAKENING SHORT WAVE ENERGY
ARRIVING FROM THE SOUTHWEST...AND FORECAST WILL REFLECT THIS. SHORT
WAVE TROUGH CROSSES MICHIGAN EARLY MONDAY ALONG WITH ITS ATTENDANT
SURFACE LOW. MONDAY COULD BE A SYNOPTIC-TO-LAKE EFFECT TRANSITION
DAY AS BOUNDARY LAYER FLOW VEERS MORE WESTERLY WITH SURFACE LOW
PASSAGE DURING THE FIRST PART OF THE DAY. WILL TREND THE FORECAST
DRIER FOR THE AFTERNOON ACROSS MUCH OF NORTHEAST LOWER...WITH OPEN
ENDED POPS FOR NORTHWEST LOWER (TRANSITION AREA) AND EASTERN UPPER
AS SYNOPTIC SNOW MAY LINGER INTO THE AFTERNOON.

AS FOR THE FIRST STAB AT POTENTIAL SNOWFALL AMOUNTS...LOOKS LIKE
SNOW RATIOS SHOULD STILL BE PRETTY HIGH GIVEN THE COLD PROFILE
ESPECIALLY SUNDAY NIGHT. SO ALTHOUGH TOTAL LIQUID QPF WILL NOT BE
TREMENDOUS...SYSTEM COULD BE AN EFFICIENT SNOW PRODUCER. WILL ALSO
NEED TO CONSIDER LAKE ENHANCEMENT IN SOUTHEAST FLOW OFF LAKE HURON
AND TO A LESSER EXTENT OFF LAKE MICHIGAN IN THE EASTERN U.P..
CURRENT THINKING IS TO START WITH 2-5 INCHES ACROSS MUCH OF THE
AREA...WITH 5+ INCHES POSSIBLE OVER EASTERN PORTIONS OF CHIPPEWA/
MACKINAC COUNTIES WITH LAKE HURON ENHANCEMENT POSSIBLE.

EXTENDED FORECAST (TUESDAY THROUGH FRIDAY)...SPECIFICS FOR THE
EXTENDED PERIOD WILL MAINLY DEAL WITH VARYING SNOW CHANCES...WHICH
WILL BE NUMEROUS BETWEEN TUESDAY`S CLIPPER AND VARIOUS LAKE EFFECT/
LAKE ENHANCEMENT.  DEPENDING ON HOW TUESDAY`S CLIPPER EVOLVES COULD
BE A SET UP FOR SOUTHWEST FLOW SNOWFALL ENHANCEMENT INTO PARTS OF
EASTERN UPPER/NORTHWEST LOWER.  850MB TEMPERATURES LOOK TO FALL
BELOW -20C TUESDAY NIGHT/WEDNESDAY WITH CONSISTENT WEST-NORTHWEST
FLOW PUSHING ACCUMULATING SNOW BANDS OFF LAKES SUPERIOR/ MICHIGAN.
TEMPERATURES WELL BELOW AVERAGE THROUGH THURSDAY...TEENS/LOWER 20S
FOR TUESDAY...MOSTLY TEENS WEDNESDAY (AND MAY BE BARELY TEENS IN
SPOTS)...THEN STARTING TO MODERATE FOR THURSDAY/FRIDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1100 PM EST FRI DEC 6 2013

WESTERLY FLOW LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO FALL
ACROSS NW AND FAR NRN LWR MICHIGAN THRU SATURDAY EVENING. LOW VFR
CONDITIONS WILL PREVAIL ACROSS ALL NRN LWR MICHIGAN TAF SITES...
ALTHOUGH CONDITIONS WILL TEMPORARILY DROP TO MVFR WITHIN SOME
HEAVIER SNOW SHOWER ACTIVITY. WEST WINDS AROUND 10 KTS TONIGHT
WILL GUST TO 15 TO 20 KTS ON SATURDAY.

&&

.MARINE...
ISSUED AT 401 PM EST FRI DEC 6 2013

SEASONABLY STRONG FLOW IS EXPECTED ACROSS THE WATERS THROUGH
SATURDAY...WITH SMALL CRAFT ADVISORIES IN EFFECT. A BRIEF RETURN TO
LIGHTER WINDS IS FORESEEN FOR A TIME ON SUNDAY...BEFORE LOW PRESSURE
PASSES THROUGH THE REGION SUNDAY NIGHT. THAT FEATURE WILL USHER IN
ANOTHER SURGE OF STRONGER WINDS AND COLD AIR TO BEGIN THE WORK WEEK.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST SATURDAY FOR MIZ008.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR LMZ323-341-342-
     344>346.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR LSZ321.

&&

$$

UPDATE...MR
SYNOPSIS...TJL
SHORT TERM...LAWRENCE
LONG TERM...JPB
AVIATION...MR
MARINE...LAWRENCE