Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 261746
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1246 PM EST FRI DEC 26 2014

.UPDATE...
ISSUED AT 936 AM EST FRI DEC 26 2014

CURRENT SFC OBS AND SATELLITE DATA SHOWING VEIL OF LOW CLOUDS ACROSS
THE NORTHERN GREAT LAKES AND WISCONSIN...WHILE SOME PATCHY DRIZZLE
LINGERS ACROSS THE STRAITS AND ERN UPPER MICHIGAN. CURRENT CONDS ARE
THE RESULT OF A NEARLY STAGNANT PATTERN LINGERING OVER THE GREAT
LAKES...CONSISTING OF A LARGE AREA OF HIGH PRESSURE ANCHORED OVER
THE ERN THIRD OF THE COUNTRY WHILE A WEAK FRONTAL SYSTEM STRETCHES
ACROSS THE UPPER MIDWEST. ONLY SOME EASTWARD PROGRESSION OF THIS
PATTERN IS EXPECTED THROUGH TONIGHT.

THE CURRENT FORECAST ACROSS THE CWA IS IN LINE WITH ONLY MINOR
ADJUSTMENTS TO CLOUDS AND TEMPS NEEDED. ANY MAJOR PCPN ACROSS
NORTHERN MICHIGAN WILL HOLD OFF UNTIL EARLY SATURDAY MORNING WHEN
MODEL SOUNDINGS SHOW MID AND UPPER LVL MSTR INCREASING ACROSS THE
REGION.

&&

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 413 AM EST FRI DEC 26 2014

OVERVIEW: SPLIT UPPER TROUGH AXIS IS STRETCHED THROUGH THE WESTERN
CONUS WITH A PSEUDO-CLOSED MID LEVEL LOW/VORTICITY MAXIMA OVER THE
4-CORNERS REGION...AND ANOTHER SHORT WAVE MOVING THROUGH SRN
MANITOBA. LOW AMPLITUDE RIDGING IS IN PLACE ACROSS MUCH OF THE
EASTERN CONUS AND A FAIRLY TIGHT BAROCLINIC ZONE STRETCHES FROM
THE CENTRAL PLAINS INTO THE GREAT LAKES. WEAKISH MID LEVEL
DEFORMATION AXIS AND SPOTTY LIGHT PRECIP ALSO EXTENDS FROM THE
PLAINS INTO THE NRN GREAT LAKES. BUT MOISTURE ALONG THAT AXIS IS
NOT PARTICULARLY DEEP...AND OBS IN EASTERN UPPER MICHIGAN HAVE
REPORTED BRIEF LIGHT PRECIP THROUGH THE OVERNIGHT...BOUNCING FROM
FLURRIES TO DRIZZLE (POSSIBLY FREEZING DRIZZLE).

TODAY...MAINLY CLOUDY SKIES ANTICIPATED ALTHOUGH SOME WARMER/DRIER
AIR SKIRTING THROUGH THE LOWER GREAT LAKES MIGHT BRING SOME THINNER
CLOUD COVER TO SRN/ERN COUNTIES OF NRN LOWER MICHIGAN. TO THE
NORTH...NARROW DEFORMATION AXIS PRETTY MUCH REMAINS DRAPED ACROSS
UPPER MICHIGAN BACK INTO THE PLAINS THROUGH THE DAY AND MAY CONTINUE
TO PRODUCE SOME VERY LIGHT SNOW OR DRIZZLE (LIGHT FREEZING DRIZZLE
THIS MORNING).

TONIGHT...SHORT WAVE ENERGY IN THE SW CONUS BEGINS TO EJECT THROUGH
THE CENTRAL PLAINS...ON IT/S WAY TO PHASING BACK UP WITH THE NRN
STREAM IN SOUTH CENTRAL CANADA. STILL EXPECT TO SEE A NICE SFC LOW
SPIN-UP IN THE CENTRAL PLAINS...ALONG THE BAROCLINIC ZONE...AND
ADVANCE UP INTO SRN WISCONSIN BY SATURDAY MORNING. MAIN BATCH OF
FORCING/PRECIP ARRIVES SATURDAY. BUT EXPECT PRECIP TO BEGIN
EXPAND/INCREASING OVERNIGHT ALONG AFOREMENTIONED DEFORMATION AXIS
AND INVERTED SFC TROUGH THAT WILL BE NOSING UP THROUGH THE TIP OF
THE MITT/STRAITS REGION BY MORNING. THERMAL PROFILES SUGGEST
SNOW...ALTHOUGH A BIT MIXY FOR PARTS OF NRN LOWER MICHIGAN AS
ELEVATED WARM NOSE GETS SHOVED INTO NRN LOWER MICHIGAN TOWARD
SATURDAY MORNING.

&&

.SHORT TERM...(SATURDAY THROUGH SUNDAY NIGHT)
ISSUED AT 413 AM EST FRI DEC 26 2014

...ANOTHER MESSY PRECIP EVENT TO START THE WEEKEND...

HIGH IMPACT WEATHER POTENTIAL: NOTHING TOO SIGNIFICANT. STILL
WATCHING THE POTENTIAL FOR SOME ACCUMULATING SNOW SATURDAY ACROSS
THE FAR NORTH.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: PATTERN REMAINS ACTIVE AND
AMPLIFIED...WITH DEEP TROUGHING EXTENDING NORTH/SOUTH ACROSS THE
INTERMOUNTAIN WEST...WHILE NORTHEAST EXTENT OF BROAD SUBTROPICAL
RIDGING POKES NORTH THROUGH THE OHIO VALLEY INTO THE GREAT LAKES.
COUPLE WELL ORGANIZED SHORTWAVES OF INTEREST WITHIN BROADER WESTERN
TROUGH REGIME...THE MOST PROMINENT OF WHICH ARE FOUR-CORNERS WAVE
AND DUAL WAVE STRUCTURE DIVING SOUTHEAST THROUGH THE NORTHERN CANADA
PRAIRIES. FURTHER UPSTREAM...WHOLE PACIFIC PATTERN REALLY SHOWING
SIGNS OF AMPLIFICATION/SLOWING...DRIVEN BY DEEP NORTHWEST BASIN
TROUGHING AND SUBSEQUENT FAR EAST PACIFIC ELONGATED RIDGING. THIS
FORETELLS OF COLDER DAYS AHEAD FOR THE UPPER MIDWEST AND GREAT LAKES
AS EAST PACIFIC RIDGE BUILDING EVENTUALLY FORCES A MORE CLASSIC
NORTHWEST FLOW RESPONSE INTO THE REGION. GETTING TO THAT COLDER
PATTERN LOOKS TO INVOLVE ONE MORE SLUSHY PRECIPITATION EVENT AS AT
LEAST PART OF FOUR CORNERS WAVE PACKET OPENS UP AND RACES ACROSS THE
NORTHERN LAKES TO START THIS WEEKEND.

PRIMARY FORECAST CHALLENGES/CONCERNS: PRECIPITATION TRENDS...BOTH
TYPE AND AMOUNT...ON SATURDAY. SNOW ACCUMULATIONS FOR PARTS OF THE
AREA WILL ALSO NEED ADDRESSING.

DETAILS: AREA OF MIXED PRECIP EXPECTED TO BE RAPIDLY EXPANDING
ACROSS THE AREA SATURDAY MORNING IN RESPONSE TO FAST APPROACHING MID
LEVEL WAVE (PART OF THAT CURRENT FOUR CORNERS SHORTWAVE) AND
ATTENDANT DEVELOPING LOW PRESSURE ACROSS THE SOUTHWEST LAKES. NOT AN
OVERLY ROBUST SYSTEM BY NO MEANS GIVEN STEADILY SHEARING MID LEVEL
SUPPORT. MOISTURE FEED SOMEWHAT MORE RESPECTABLE WITH SOUTHEAST
CONUS CENTERED SURFACE HIGH ALLOWING AT LEAST SOME GULF OF MEXICO
MOISTURE CONTRIBUTION. PRE-SYSTEM PWAT VALUES RESPOND
ACCORDINGLY...PUSHING UP AND JUST OVER HALF AN INCH. DESPITE
SHEARING MID LEVEL SUPPORT...SYSTEM SHOULD HAVE SOME DECENT FGEN
RESPONSE WITH IT AS LOW/MID LEVEL THERMAL GRADIENT BEGINS TO RAMP UP
VIA LEAD CANADIAN WAVE PUSHING ACROSS ONTARIO. WITH THAT SAID...FGEN
RESPONSE SHOULD BE NOT OVERLY AGGRESSIVE...WITH MOST CENTERED SUB H7
LEVEL. STRONGEST RESPONSE LOOKS CENTERED AROUND H8 THERMAL
GRADIENT...WITH LAST TRENDS SUPPORTING "WARM" SIDE LIFT CENTERED ON
THE STRAITS. SURFACE BAROCLINIC AXIS SETS UP JUST TO THE SOUTH OF
THIS ZONE...SUPPORTING NOW NEARLY UNANIMOUS SUPPORT FOR SLOWLY
DEEPENING/EXTREMELY FAST MOVING SURFACE LOW TO RIDE UP ACROSS THE
TIP OF THE MITT DURING THE DAY SATURDAY...HAVING EXITED WELL TO OUR
EAST BY EARLY SATURDAY EVENING.  THERMAL REGIME AND SAID SURFACE
TRACK CONTINUES TO SUPPORT A CLASSIC NORTHERN LOWER RAIN/EASTERN
UPPER SNOW DELINEATION...WITH MIXED RAIN/SNOW FOCUSED ACROSS THE TIP
OF THE MITT AND UP INTO THE HIGHLANDS OF NORTHERN LOWER.

AS FOR SNOW AMOUNTS: NOT EXPECTING ANYTHING TOO SIGNIFICANT...WITH
CURRENT INDICATIONS BEST FGEN RESPONSE WILL OCCUR IN A VERY MARGINAL
THERMAL ENVIRONMENT THROUGH THE STRAITS AREA. COLDER PROFILES AS ONE
GOES FURTHER NORTH ACROSS EASTERN UPPER...SUPPORTING GRADUALLY
HIGHER SNOW/LIQUID RATIOS. ALL TOLD...COULD SEE A FEW INCHES ACROSS
EASTERN UPPER...WITH MINIMAL AMOUNTS AS ONE HEADS SOUTH OF THE BIG
BRIDGE.

AS MENTIONED...SYSTEM IS AN AWFULLY QUICK MOVER...WITH SYNOPTIC
SCALE SUPPORT QUICKLY WANING SATURDAY EVENING. FOCUS THEN TURNS TO
LAKE RESPONSE FOR THE REMAINDER OF THE WEEKEND AS BACKSIDE CAA DROPS
H8 TEMPERATURES AOB -10C OVERNIGHT...WITH A SECONDARY COLD FRONT
SLATED TO DROP THROUGH THE REGION OF SUNDAY...FURTHER DROPPING
TEMPERATURES. NO MATTER HOW YOU SLICE IT...JUST NOT LOOKING LIKE
ANYTHING SIGNIFICANT...WITH SYSTEM MOISTURE EXITING JUST AS
FAVORABLE OVER-WATER THERMAL ENVIRONMENT ARRIVES SATURDAY NIGHT.
EVEN MORE FAVORABLE THERMAL REGIME ARRIVES ALONG/BEHIND FRONT
SUNDAY...WITH ONLY A NARROW WINDOW OF ANY SYNOPTIC SCALE SUPPORT TO
ENHANCE AN ALREADY IN-PLACE LAKE RESPONSE. ALL TOLD...JUST LOOKING
FOR LIGHT SNOW SHOWERS...MOST NUMEROUS IN THE SNOW BELTS OF EASTERN
UPPER GIVEN SOMEWHAT DEEPER MOISTURE AND LONGER LAKE SUPERIOR FETCH.
ANY ACCUMULATIONS WILL BE MINIMAL.

&&

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 346 PM EST THU DEC 25 2014

COLD AIR WILL FILTER INTO THE REGION BEHIND A LOW PRESSURE SYSTEM
MOVING THROUGH ON SATURDAY. THE INFLUX OF COLD AIR WILL RESULT IN
LINGERING CHANCES FOR LAKE EFFECT SNOWS IN AREAS FAVORED WITH WEST
AND NORTHWEST FLOW. THIS WILL PERSIST THROUGH MOST OF THE WEEK WITH
ARRIVAL OF A CLIPPER SYSTEM ON THURSDAY BRINGING MORE WIDESPREAD
CHANCES FOR SNOW...THOUGH LACK OF AVAILABLE MOISTURE SHOULD KEEP
TOTALS MODEST. HIGH TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL IN
THE LOW TO MID 20S...WITH SOME AREAS IN THE TEENS MID WEEK. LOW
TEMPERATURES WILL BE IN THE TEENS...WITH SOME INTERIOR LOCATIONS
DIPPING INTO SINGLE DIGITS MID WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM EST FRI DEC 26 2014

CURRENT VFR VSBYS AND IFR/MVFR CIGS AT NRN MI TAF SITES IS EXPECTED
TO CONTINUE INTO THIS EVENING...THE RESULT OF A NEARLY STATIONARY
SYNOPTIC PATTERN ACROSS THE ERN ONE HALF OF THE COUNTRY. HOWEVER IFR
CIGS AND VSBYS CAN BE EXPECTED ACRS THE NRN LAKES OVERNIGHT. DRIZZLE
OR FREEZING DRIZZLE IS POSS THIS EVENING DUE TO THE LACK OF MID AND
UPPER LVL MSTR...WITH ANY RAIN/SNOW MIX AT DAWN BECOMING ALL RAIN BY
LATE MORNING IN ADVANCE OF APPROACHING PLAINS FRONTAL BOUNDARY.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

UPDATE...SWR
NEAR TERM...ADAM
SHORT TERM...MSB
LONG TERM...ALM
AVIATION...SWR


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