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000
FXUS63 KAPX 091215
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
715 AM EST MON DEC 9 2013

.SYNOPSIS...
ISSUED AT 455 AM EST MON DEC 9 2013

WIDESPREAD SNOW WILL TAPER OFF THIS MORNING AS A WEAK LOW PRESSURE
SYSTEM MOVES OUT OF THE AREA. COLD AIR AND GUSTY WESTERLY WINDS
BEHIND THIS SYSTEM WILL GENERATE LAKE EFFECT SNOW FOR NORTHWEST
LOWER MICHIGAN. ANOTHER ALBERTA CLIPPER WILL ARRIVE TUESDAY WITH
MORE SNOW.  ANOTHER SHOT OF FRIGID AIR WILL ARRIVE BY MIDWEEK.

&&

.UPDATE...
ISSUED AT 659 AM EST MON DEC 9 2013

EXTENDED THE SNOW ADVISORY FOR CHIP/MACK COUNTIES AN EXTRA COUPLE
OF HOURS AS SYSTEM SNOW AND LAKE ENHANCED SNOWS CONTINUE ACROSS
THE AREA. ALREADY HAD 5 TO AS MUCH AS 8 INCHES...ON EARLY MORNING
REPORTS. MOISTURE REALLY STRIPPED OUT ACROSS THE FAR SE
CWA...CLOSER TO WARMER LOW LEVEL AIR NOT WHERE TOP OF THE MOIST
LAYER COULD BRIEFLY DIP TO -10C FOR THE SMALL CHANCE OF SEEING
SOME FREEZING DRIZZLE (REPORTS OF THIS UPSTREAM ACROSS GRR). THIS
LIKELY TOO FAR SOUTH TO AFFECT OUR CWA.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 455 AM EST MON DEC 9 2013

CURRENTLY...LOW PRESSURE AND ASSOCIATED SHORTWAVE WAS LIFTING
THROUGH NE LOWER MICHIGAN. DEEPER MOISTURE OUT AHEAD OF THIS LOW
WAS ALREADY PUSHING OUT OVER LAKE HURON...BUT DEFORMATION SNOWS
WERE STILL STRETCHED BACK ACROSS AREAS ALONG AND NORTH OF M-32 AND
EASTERN UPPER. SOUTH OF THERE...DEEPER MOISTURE AND FORCING HAS
BEEN STRIPPED OUT ALOFT WITH JUST SOME VERY LIGHT SNOW AND
FLURRIES BEING COMMON. ANOTHER SHARPER SHORTWAVE/TROUGH WAS ACROSS
THE DAKOTAS AND MN...WITH A CORE OF STRONGER LOW LEVEL WINDS
DEVELOPING ACROSS THE MID AND UPPER MISSISSIPPI VALLEY. THIS WAVE
IS LACKING IN ANY APPRECIABLE MOISTURE AND/OR SIGNIFICANT DEEP
LAYER FORCING...WHICH IS ALSO LIFTING/SHEARING NE.

TODAY AND TONIGHT...THE LOW PRESSURE WILL CONTINUE LIFTING NNE
THIS MORNING AND WILL ALSO BE STRENGTHENING WITH TIME....AS THE
UPSTREAM SHARPER SHORTWAVE/TROUGH TREKS INTO THE NRN GREAT LAKES.
AS DEFORMATION/DEEPER MOISTURE CONTINUES TO SHUNT ITSELF EASTWARD
WITH THE ENTIRE PATTERN...WE WILL BE DEVELOPING A TIGHTER PRESSURE
GRADIENT WITH A SLIGHT BACKING OF THE LOW LEVEL FLOW WITH THE
WAVE`S ARRIVAL. SO...SYSTEM SNOWFALL WILL GRADUALLY WANE...BUT
STRENGTHENING WINDS OUT OF THE WEST WILL INCREASE COLD ADVECTION
AND DEEPEN OVERLAKE INSTABILITY...MAXING OUT THIS EVENING WITH
INVERSION HEIGHTS OF NEAR 7KFT. A WSW FLOW WILL VEER AND SETTLE
DUE WEST AFTER THE WAVE`S PASSING THIS EVENING...BUT INVERSION
HEIGHTS/MOISTURE FALL BACK. LAKE EFFECT SNOWS WILL BE FAIRLY
DECENT THIS EVENING...BOUNDED BY WEAKER LAKE EFFECT FROM LATE
MORNING THROUGH ALL OF TONIGHT. EMMET...CHEBOYGAN AND CHARLEVOIX
COUNTIES ARE PEGGED WITH THE LAKE EFFECT AT ALL TIMES...AND CAN
EASILY SEE ADVISORY LEVEL SNOWS OF A GOOD 3-6 INCHES BY NIGHT`S
END. WESTERLY GUSTS OF 25-30MPH WILL BE ABLE TO SHOVE SNOWS WELL
INLAND AND FURTHER REDUCE VISIBILITY DUE TO AREAS OF BLOWING SNOW.
EASTERN UPPER...AFTER THE SYSTEM SNOWS END...WILL SEE LITTLE IN
THE WAY ADDITIONAL SNOWFALL...WITH THE EXCEPTION OF MAYBE DRUMMOND
ISLAND....AND WHITEFISH POINT.


.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 455 AM EST MON DEC 9 2013

REINFORCING SHOTS OF ARCTIC AIR WILL CONTINUE TO FLOW INTO THE
REGION FOR MUCH OF THIS WEEK LEADING TO ADDITIONAL BOUTS OF LAKE
EFFECT SNOW SHOWERS. SHIFTING WINDS AND VARYING AMOUNTS OF AVAILABLE
MOISTURE DUE TO WEAK ALBERTA CLIPPER SYSTEMS MOVING THROUGH THE
FLOW...WILL LEAD TO DAILY FORECAST CHALLENGES OVER THE LOCATION AND
INTENSITY OF THE LAKE EFFECT SNOW SHOWERS AND THE RESULTANT
ACCUMULATIONS. THINGS BECOME DICEY TO END THE WEEK INTO NEXT WEEK
WITH EXTENDED MODELS VARYING ON THE AMOUNT OF "WARMING" AND
MOISTURE...SO WILL KEEP THE FORECAST GENERAL WITH A CHANCE FOR SNOW
SHOWERS.

TUESDAY...AN ALBERTA CLIPPER WILL MOVE BY TO THE NORTH LEADING TO AN
UPTICK IN MOISTURE AS WELL AS WIDESPREAD MAINLY LIGHT SNOW. THE
EXCEPTION TO THE LIGHT SNOW WILL BE ACROSS SOUTHWEST AND EVENTUALLY
WESTERLY FLOW FAVORED AREAS WHERE LAKE ENHANCEMENT WILL LIKELY LEAD
TO STEADIER AND POSSIBLY HEAVIER SNOW. ACCUMULATIONS WILL RANGE FROM
LESS THAN AN INCH ACROSS SOUTHEAST ZONES TO UPWARDS OF A FEW INCHES
IN LAKE ENHANCEMENT AREAS ALONG THE NORTHWEST LAKE MICHIGAN
SHORELINE...ACROSS THE STRAITS AND POSSIBLY IN EASTERN MACKINAC
COUNTY. BRISK WINDS WILL LEAD TO AREAS OF BLOWING AND DRIFTING SNOW
AS WELL. HIGHS RANGING FROM THE MIDDLE TEENS TO LOWER 20S.

TUESDAY NIGHT INTO WEDNESDAY NIGHT...MOISTURE REMAINS RATHER ROBUST
WITH 850-700 MB RH BETWEEN 70 AND 80 PERCENT. MEANWHILE...THE
COLDEST AIR OF THE WEEK DROPS DOWN FROM THE NORTHWEST WITH 850 MB
TEMPS FALLING INTO THE -20 TO -23 C). THIS WILL POSSIBLY SET THE
STAGE FOR A MORE SIGNIFICANT AND WIDESPREAD LAKE EFFECT EVENT FOR
WEST OR WEST NORTHWEST FLOW FAVORED AREAS...WHERE SEVERAL INCHES OF
ACCUMULATION WILL BE POSSIBLE. LOWS IN THE SINGLE DIGITS TO AROUND
10 ABOVE WITH HIGHS IN THE MIDDLE TO UPPER TEENS.

THURSDAY...LAKE EFFECT SNOW SHOWERS CONTINUE WITH PLENTY OF
REMAINING OVER LAKE INSTABILITY. ACTIVITY MAY EVEN BE ENHANCED BY
ANOTHER CLIPPER SYSTEM MOVING ACROSS THE REGION. THE MEAN FLOW LOOKS
TO BE OUT OF THE WEST...BUT THIS OF COURSE IS SUBJECT TO CHANGE.
HIGHS IN THE MIDDLE TEENS TO AROUND 20.

FRIDAY THROUGH SUNDAY...THERE ARE LOTS OF QUESTION MARKS TO END THE
WORK WEEK RIGHT INTO NEXT WEEKEND AS EXTENDED MODELS HAVE DEVELOPED
A BAROCLINIC ZONE ACROSS NORTHERN MICHIGAN BETWEEN FRIGID AIR TO THE
NORTH AND MILDER AIR TO THE SOUTH. THIS SCENARIO WOULD SET THE STAGE
FOR A PROLONGED PERIOD OF SNOW SHOWERS OR LIGHT SNOW...WITH PERHAPS
SOME LAKE CONTRIBUTION FROM TIME TO TIME AS WELL (THOUGH ACTUAL MEAN
FLOW IS TOO HARD TO SURMISE AT THIS TIME). SO WILL BE FORCED TO GO
WITH GENERIC LOW CHANCE POPS FOR SNOW SHOWERS THROUGH THIS ENTIRE
TIME. TEMPERATURES ARE EXPECTED TO REMAIN COLD WITH HIGHS IN THE
UPPER TEENS TO LOWER 20S AND LOWS IN THE UPPER SINGLE DIGITS AND
TEENS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 659 AM EST MON DEC 9 2013

PRIMARILY MVFR ALL TAF SITES...WITH WORST OF CONDITIONS FOCUSED ON
PLN.

WEAK LOW PRESSURE IS LIFTING NNE OF THE REGION...WITH TRAILING
SYSTEM SNOWFALL CONTINUING TO TAPER OFF. TIGHTER PRESSURE
GRADIENT AND DEEPER COLD ADVECTION SETTING IN BEHIND THE DEPARTING
LOW. THIS WILL RESULT IN THE DEVELOPMENT OF LAKE EFFECT SNOWS
WHICH WILL MAINLY IMPACT PLN...AS LOW LEVEL WINDS BACK A TOUCH
SOUTH OF WEST. THESE WINDS WILL ALSO BECOME QUITE GUSTY REACHING
IN AND AROUND 30 MPH...RESULTING IN PERIODS OF LAKE EFFECT SNOW
AND BLOWING SNOW WITH IFR CONDITIONS. STRONGEST SNOW SHOWERS ARE
EXPECTED 22-02Z WITH THE PASSAGE OF A SFC TROUGH.
THEN...DRYING/SUBSIDENCE ALOFT WILL TAPER OFF THE SNOW. THIS
SNOWFALL WILL GET REVITALIZED TUESDAY WITH THE APPROACH OF AN
ALBERTA CLIPPER.

&&

.MARINE...
ISSUED AT 420 AM EST MON DEC 9 2013

LIGHT AND VARIABLE WINDS THIS MORNING DUE TO PASSING WEAK LOW
PRESSURE OVERHEAD...WILL SWITCH TO OUT OF THE WSW...AND INCREASE
TODAY...DUE TO A TIGHTER PRESSURE GRADIENT AND DEEPER OVERLAKE
INSTABILITY. GALE FORCE GUSTS WILL DEVELOP OVER MANY OF THE GREAT
LAKES NEARSHORE WATERS AND CONTINUE INTO A GOOD PORTION OF
TONIGHT. WINDS WILL STAY GUSTY THROUGH THURSDAY WITH ADVISORIES
LIKELY OUT FOR SEVERAL NEARSHORE WATERS AT ANY GIVEN TIME. HIGHER
PRESSURE AND MORE CALM CONDITIONS DEVELOPS FRIDAY.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MIZ008-015.
     WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 6 AM EST
     WEDNESDAY FOR MIZ016-017-019.
LH...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 4 AM EST
     TUESDAY FOR LHZ349.
     GALE WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST TUESDAY FOR
     LHZ345>348.
LM...GALE WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST TUESDAY FOR
     LMZ323-341-342-344>346.
LS...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 4 AM EST
     TUESDAY FOR LSZ322.
     GALE WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST TUESDAY FOR
     LSZ321.

&&

$$

UPDATE...SD
SYNOPSIS...AS
SHORT TERM...SD
LONG TERM...AS
AVIATION...SD
MARINE...SD