Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 202115
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
415 PM EST THU NOV 20 2014

.SYNOPSIS...
ISSUED AT 407 PM EST THU NOV 20 2014

LAKE EFFECT SNOW...AT TIMES HEAVY...WILL CONTINUE IN THE TRADITIONAL
SNOW BELT AREAS TODAY. HIGH PRESSURE BRINGS A GRADUAL END TO LAKE
SNOWS TONIGHT...AND ESPECIALLY ON FRIDAY. MILDER WEATHER ARRIVES FOR
THIS WEEKEND INTO THE START OF NEXT WEEK...ALONG WITH PERIODS OF
RAIN.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 407 PM EST THU NOV 20 2014

...LAKE EFFECT WINDING DOWN TONIGHT...

OVERVIEW: STACKED LOW PRESSURE SYSTEM OVER SOUTHWEST QUEBEC THIS
AFTERNOON...CONTINUES TO SLOWLY PULL AWAY TO THE EAST WITH DEEP
CYCLONIC FLOW EASING OFF A BIT. LOW LEVEL TROUGH AXIS STILL
STRETCHES BACK THROUGH EASTERN LAKE SUPERIOR WITH A DECENT LOW LEVEL
CONVERGENCE AXIS AND SEVERAL STRONG LAKE EFFECT BANDS POINTING INTO
EASTERN UPPER MICHIGAN. ACROSS LOWER MICHIGAN...LAKE EFFECT
CONVECTION HAS EASED OFF A BIT THIS AFTERNOON WITH RADAR ESTIMATED
SNOWFALL RATES NOW RUNNING HALF TO ONE INCH PER HOUR. LAKE BANDING
HAS ALSO BECOME MORE DIFFUSE-CELLULAR OVER THE LAST FEW HOURS
THROTTLING AFTERNOON SNOW ACCUMULATIONS. UPSTREAM...LARGE EXPANSE OF
HIGH PRESSURE/SUBSIDENCE/DRY AIR IS JUST ACROSS THE LAKE.

THIS EVENING...STILL A FEW MORE HOURS OF OPPORTUNITY FOR DECENT LAKE
EFFECT SNOWS. HIGH RESOLUTION GUIDANCE SUGGESTS AFOREMENTIONED LOW
LEVEL TROUGH ACROSS EASTERN UPPER MICHIGAN SAGS DOWN THROUGH NRN
LOWER MICHIGAN THIS EVENING...WHICH MAY DRAG SOME OF THE HEAVIER
LAKE BANDING INTO THE TIP OF THE MITT COUNTIES FOR A FEW HOURS THIS
EVENING. MEANWHILE...LOW LEVEL MEAN FLOW VEERING MORE NORTHWESTERLY
MAY FOCUS SOME HEAVIER LAKE SNOWS INTO THE TRADITIONAL SNOW BELTS OF
NW LOWER MICHIGAN THIS EVENING (LAKE BANDING HAS BEEN TRENDING THAT
WAY OVER THE LAST HOUR OR SO)...BEFORE THINGS TAPER OFF IN EARNEST
OVERNIGHT. BUT ALL TOLD...GIVEN THE DRY AIR/LOWERING INVERSIONS...I
THINK ANOTHER 2 TO 4 INCHES WHERE SNOW SHOWERS PERSIST SHOULD JUST
ABOUT DO IT...WITH SOME LOCALIZED HIGHER AMOUNTS.

HEADLINES...ALWAYS A TOUGH CALL NEAR THE END OF AN EVENT. ADDITIONAL
FORECAST SNOWFALL DOESN/T RISE TO WARNING CRITERIA...BUT YOU DON/T
FEEL COMPLETELY COMFORTABLE TRIMMING OUT HEADLINES YET AND YOU DON/T
WANT TO CONFUSE THE ISSUE BY STAIR-STEPPING OUT OF WARNINGS.
SO...WITH ADDITIONAL ACCUMULATING SNOWS/PERIODIC LOW VSBYS THIS
EVENING IN THE SNOW BELTS...WILL LEAVE MANY OF THE HEADLINES INTACT
FOR NOW AND LET EVENING SHIFT CUT/TRIM AS THINGS WIND DOWN LATER ON.
THAT SAID...I HAVE TRIMMED OUT A FEW OF THE ADVISORY COUNTIES WHERE
RELATIVELY MINOR ACCUMULATIONS WILL OCCUR TONIGHT.

&&

.LONG TERM...(FRIDAY THROUGH THURSDAY)
ISSUED AT 407 PM EST THU NOV 20 2014

FRIDAY WILL BEGIN A TRANSITION PERIOD ACROSS THE STATE...FROM
PERSISTENT COLD AND SNOW TOWARD MILDER TEMPERATURES AND CHANCES OF
RAIN. THE DOMINANT DEEP UPPER TROUGH WHICH HAS BEEN IN PLACE ACROSS
THE GREAT LAKES AND UPPER MIDWEST DURING THE PAST WEEK...WILL
FINALLY EXIT EAST OF THE GREAT LAKES FRIDAY NIGHT WHILE UPPER
RIDGING BUILDS OVER THE PLAINS. AT THE SFC...A WEAKENING AREA OF LOW
PRESSURE WHICH EXITED THE GREAT LAKES INTO QUEBEC ON THURSDAY...
WILL QUICKLY BE REPLACED BY A LARGE AREA OF HIGH PRESSURE BUILDING
INTO THE OHIO VALLEY AND GREAT LAKES. THIS OVERALL PATTERN WILL
EVENTUALLY BRING AN END TO THE RECENT BOUT OF LAKE INDUCED SNOWS AND
BELOW NORMAL TEMPS WHICH HAVE BEEN PRESENT ACROSS NRN MI.

HOWEVER DURING THIS TRANSITION PERIOD...LAKE EFFECTS WILL CONTINUE
ACRS THE WRN LAKES FRIDAY MORNING THE RESULT OF LINGERING MID LVL
NORTHWEST FLOW COMBINING WITH 850MB TEMPS ARND -20C. HOWEVER LAKE
INFLUENCES WILL DIMINISH QUICKLY ACROSS THE GREAT LAKES FRIDAY
AFTERNOON AS 850MB TEMPS WARM TO AROUND -4C AND 925/850MB WINDS
TREND SOUTHWEST...COMBINED WITH MODEL SOUNDINGS SHOWING MID LVL MSTR
DIMINISHING FROM AROUND 80/90PCT EARLY TO UNDER 40 PCT FRIDAY
AFTERNOON AND FRIDAY EVENING.

THE DRY CONDS ACRS THE GREAT LAKES FRIDAY EVENING WILL BE SHORT
LIVED...AS MODEL SOUNDINGS AND MSTR PROGS SHOW MID LVL MSTR
STREAMING BACK INTO THE GREAT LAKES BY 12Z SATURDAY...AS GULF MSTR
BEGINS TO LIFT NORTH ON THE BACK SIDE OF HIGH PRESSURE ANCHORED OVER
THE SOUTH ATLANTIC SEABOARD.

SATURDAY THRU MONDAY AFTERNOON...A COUPLE OF WEATHER SYSTEMS WILL
PASS THROUGH THE GREAT LAKES THIS WEEKEND...GENERATING MILD
TEMPERATURES AND RAIN ACROSS THE STATE. THE FIRST SYSTEM...A WEAK
FEATURE CURRENTLY MOVING OVER WRN CANADA...WILL GET THE WARMING
TREND STARTED AS IT SWEEPS OVER THE GREAT LAKES SATURDAY WARMING MID
LVL TEMPS TO AROUND +2C. A SECOND SYSTEM WILL BECOME WELL ORGANIZED
OVER THE PLAINS SUNDAY...BEFORE LIFTING INTO THE GREAT LAKES MONDAY.
THE SECOND SYSTEM WILL BRING THE WARMEST MID LVL TEMPS TO THE STATE
THIS WEEKEND...AS 850MB TEMPS WARM FROM +2C SATURDAY TO +6C SUNDAY
AND EARLY MONDAY. MODEL SOUNDINGS SHOW VARYING AMOUNTS OF MSTR CAN
BE EXPECTED ACROSS NORTHERN MICHIGAN THIS WEEKEND. MODEL SOUNDINGS
SHOW A NEARLY SATURATED LAYER FROM THE SFC THROUGH 500MB THROUGH 12Z
SATURDAY BEFORE MID AND UPPER LVLS DRY BY SATURDAY AFTERNOON.
HOWEVER MODEL SOUNDINGS AND MSTR PROGS SHOW LIMITED MSTR ACROSS THE
GREAT LAKES SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON...BEFORE
MSTR QUICKLY OVERSPREADS NRN MI SUNDAY EVENING AND MONDAY IN ADVANCE
OF A WELL DEVELOPED SYSTEM LIFTING INTO THE WRN LAKES. OVERALL WILL
CONTINUE THE CURRENT FORECAST TREND OF MILD TEMPS NEARING THE 40S
THIS WEEKEND ACROSS THE CWA WITH PCPN MAINLY IN THE FORM OF RAIN
(EXCEPT FOR A MIX POSSIBLE EARLY SATURDAY) THE BEST CHANCE OF
WIDESPREAD SIGNIFICANT RAIN WILL BE SUNDAY AFTERNOON AND MONDAY IN
ADVANCE OF THE SYSTEM LIFTING INTO THE WRN LAKES.

MONDAY NIGHT THROUGH THURSDAY...THE WRN GREAT LAKES SYSTEM WILL LIFT
NORTHEAST INTO QUEBEC MONDAY NIGHT AND TUESDAY...BEFORE ANOTHER
SYSTEM MOVES INTO THE OHIO VALLEY AND SRN MI THURSDAY. AT UPPER
LVLS...500MB RIDGING OVER THE GREAT LAKES DURING THE WEEKEND WILL BE
REPLACED BY YET ANOTHER DIGGING TROUGH MONDAY NIGHT THROUGH
WEDNESDAY. THIS PATTERN WILL RETURN COLD TEMPERATURES AND MORE SNOW
SHOWERS TO MUCH OF NORTHERN MICHIGAN THROUGH THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1259 PM EST THU NOV 20 2014

HEAVY LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO IMPACT NW LOWER
MICHIGAN THROUGH THE AFTERNOON...RESULTING IN LOW MVFR TO IFR
CONDITIONS AT TVC/MBL AT TIMES. PLN MAY CATCH A BREAK FOR A WHILE AS
HEAVIEST SNOW SHOWERS HAVE SHIFTED A BIT FURTHER SOUTH...BUT
ANOTHER BATCH OF HEAVIER SNOWS MAY SHIFT OUT OF EASTERN UPPER AND
DOWN INTO THE TIP OF THE MITT OVER THE NEXT FEW HOURS.

SNOW SHOWERS WILL WIND THEMSELVES DOWN TONIGHT AS HIGH PRESSURE
AND DRIER AIR BUILD ACROSS THE REGION. TVC/MBL/PLN WILL LIKELY
CONTINUE TO SEE SNOW SHOWERS...BUT FLIGHT CONDITIONS WILL LARGELY
REMAIN MVFR OR BETTER. APN GETS OUT OF THE SNOW SHOWERS TONIGHT
WITH VFR CONDITIONS ANTICIPATED THERE.

WINDS...GUSTY FROM THE W/WNW THROUGH THE AFTERNOON WITH A GRADUAL
VEERING TOWARD NW (310 DEGREES) BY EVENING. GUSTINESS ENDS THIS
EVENING.


&&

.MARINE...
ISSUED AT 407 PM EST THU NOV 20 2014

LOW PRESSURE SYSTEM WILL SLOWLY EXIT EAST OF THE REGION TONIGHT
WHILE HIGH PRESSURE BUILDS IN THROUGH FRIDAY. SOME GALE FORCE
GUSTS WILL BE FOUND ON PARTS OF LAKE HURON THIS EVENING MAINLY
THAT STRETCH FROM THE STRAITS TO THUNDER BAY. BUT WINDS WILL
DIMINISH LATER TONIGHT. ELSEWHERE...SMALL CRAFT ADVISORY
WINDS/WAVES WILL PERSIST THROUGH TONIGHT.

WINDS BACK SW ON FRIDAY WITH MORE GUSTINESS DEVELOPING THROUGH THE
DAY AND PERSISTING INTO SATURDAY. ANOTHER ROUND OF SMALL CRAFT
ADVISORY HEADLINES WILL BE NEEDED...AND GALES ARE CERTAINLY A
POSSIBILITY ON LAKE MICHIGAN LATER FRIDAY THROUGH FRIDAY NIGHT.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ018-
     020-026-027.

     LAKE EFFECT SNOW WARNING UNTIL MIDNIGHT EST TONIGHT FOR MIZ016-
     017-019-021-022-028.

     LAKE EFFECT SNOW WARNING UNTIL 5 AM EST FRIDAY FOR MIZ008.

LH...SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR LHZ345-346-349.

     GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LHZ347-348.

LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR LMZ323-341-342-
     344>346.

LS...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR LSZ321-
     322.

&&

$$

SYNOPSIS...ALM
SHORT TERM...ADAM
LONG TERM...SWR
AVIATION...ADAM
MARINE...ADAM


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