Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 272338
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
638 PM EST SAT DEC 27 2014

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 359 PM EST SAT DEC 27 2014

...RETURN TO BELOW FREEZING TEMPERATURES...

HIGH IMPACT WEATHER POTENTIAL: TEMPERATURES FALLING BELOW
ZERO...FREEZING WET/SLUSHY ROADWAYS OVER EASTERN UPPER.

A WEAK AREA OF LOW PRESSURE OVER THE NORTHERN GREAT LAKES WILL
CONTINUE TO MOVE EAST...USHERING IN COLDER TEMPERATURES AND RETURN
TO SOME LAKE EFFECT SNOWS. MAIN AREA OF RAIN IS ALONG THE COLD FRONT
OVER NORTHERN LOWER MICHIGAN AND WILL CONTINUE ITS PUSH TO THE NORTH
AND EAST ALONG WITH THE LOW PRESSURE SYSTEM. THIS RAIN WILL MOVE OUT
OF THE AREA DURING THE LATE AFTERNOON/EARLY EVENING HOURS. WINDS
VEER WESTERLY AND BECOME GUSTY ALONG THE FRONT...WHERE GUSTS TO NEAR
30 MPH HAVE BEEN SEEN...AFTER THE FRONT PASSES WINDS WILL VEER TO
NORTHWESTERLY AND LIGHTEN UP A BIT...WITH GUSTS TO AROUND 15 TO 20
MPH. MAY SEE SOME LIGHT DRIZZLE IMMEDIATELY AFTER THE FRONT PASSES
AS MID-LEVELS DRY. 850MB TEMPERATURES DO NOT GET COLD ENOUGH FOR
LAKE EFFECT SNOWS TO DEVELOP UNTIL LATE TONIGHT OVER NORTHERN
CHIPPEWA COUNTY...WHITEFISH POINT AREA...AND THEN NORTHERN LOWER
UNTIL THE EARLY MORNING HOURS. THE GREATEST POTENTIAL IS OVER
NORTHERN CHIPPEWA COUNTY...WHERE AMPLE MOISTURE RESIDES AND DELTA-TS
REACH INTO THE UPPER TEENS. NORTHWEST LOWER WILL JUST SEE FLURRIES
TO LIGHT SNOW SHOWERS WITH BOTH MARGINAL DELTA-TS AND MOISTURE.
ACCUMULATIONS SHOULD BE LIGHT IN ANY LAKE EFFECT SNOW SHOWERS THAT
DO DEVELOP. TEMPERATURES WILL REACH DOWN TO THE TEENS IN EASTERN
UPPER AND 20S OVER NORTHERN LOWER BY SUNDAY MORNING.

&&

.SHORT TERM...(SUNDAY THROUGH TUESDAY)
ISSUED AT 359 PM EST SAT DEC 27 2014

HIGH IMPACT WEATHER POTENTIAL: MODERATE LAKE EFFECT SNOW SUNDAY
THROUGH MONDAY. VERY CHILLY TEMPERATURES

FORECAST CHALLENGES: SNOW AMOUNTS WITH THE LAKE EFFECT AS WE GO
THROUGH SOME DRY PERIODS DURING THE 48 HOUR PERIOD.

OVERVIEW(ANALYSIS AND FORECAST)...MAIN FEATURE IS THE 500 MB TROUGH
IN THE MIDDLE OF THE COUNTRY, WITH ASSOCIATED SFC LOW LIFTING NORTH
OF KANJ THIS AFTERNOON. COLD AIR WITH THIS FEATURE WILL BEGIN TO SPILL
INTO THE UPPER GREAT LAKES TONIGHT. THE 500 MB TROUGH ALSO ROTATES
OVER THE UPPER GREAT LAKES AND PUTS US INTO THE COLD AIR, WELL MORE
NORMAL AIR, THROUGH THE REST OF THE WEEK.

(12/28)SUNDAY...AS NOTED IN THE FORECAST CHALLENGES FOR THIS PERIOD,
THE MAIN CONCERN DURING THE NEXT 48 HOURS WILL BE THE DRY SLOTS THAT
PUSH THROUGH IN THE 850-700 MB LAYER TO INHIBIT THE LES. BETWEEN 12Z
AND 18Z, THE MOISTURE (RH>70%) IS GOOD ON THE GFS AND ECMWF WITH THE
COLD AIR MOVING INTO THE REGION AS THE 850 MB TEMPERATURES FALL TO -
14C IN E UPPER AND -12C IN N LOWER. WATER TEMPERATURES ARE AROUND 4
TO 5 C IN LAKES SUPERIOR AND MICHIGAN SO THERE WILL BE A GOOD BURST
ALONG COLD FRONT WITH THE LES HOWEVER, THE WINDS WILL BEGIN TO
SHIFT, ADDING TO THE BURST, IN E UPPER. WINDS DO A MORE GRADUAL SHIFT
IN N LOWER, WITH A BURST OF SNOW AROUND 0Z THE WIND SHIFT LINE MOVES
THROUGH N LOWER. SO WILL EXPECT THAT LIGHT AMOUNTS WILL BE THE RULE,
BUT MODERATE POCKETS AS THE SNOW BURSTS WILL BE HARDER TO NAIL DOWN
UNTIL THEY BECOME EVIDENT.

SUNDAY NIGHT...THE WINDS IN THE 1000-850 MB LAYER THEN PRETTY MUCH
HOLD NW WINDS THROUGH THE NIGHT. THE ONLY ISSUE IS THE FIRST OF THE
DRY AIR BEGINS TO MOVE INTO THE FORECAST AREA AS THE LIMITING THE
850-700 MB LAYER RH TO ABOUT 30-50% DEPENDING ON WHERE IN THE
FORECAST AREA YOU ARE. THE 850 MB TEMPERATURES FALL TO AROUND -16C
IN N LAKE MICHIGAN AND -19C IN E LAKE SUPERIOR. SO WILL EXPECT THAT
LIGHT AMOUNTS WILL CONTINUE INTO THE NW FLOW ZONES WITH THE LACK OF
SYNOPTIC MOISTURE. HOWEVER, UNTIL THE BANDS ARE ESTABLISHED AND WE
SEE HOW WELL THEY CONTINUE, THE AMOUNTS COULD VERY UP OR DOWN.

(12/29)MONDAY...STILL COLD ENOUGH FOR LES (850 MB TEMPERATURES<-20C
IN LAKE SUPERIOR), BUT WITH SUCH DRY AIR IN THE MIX ON THE GFS AND
NAM IT MAY BE PRETTY LIGHT. THE ECMWF IS A LITTLE MORE MOIST, BUT
THAT MAY BE AN ARTIFACT OF THE MODEL FROM THE EXTREME COLD ADDING
LAKE MOISTURE. SO WITH THE WINDS CONTINUING NW FLOW, WILL EXPECT
LIGHT ACCUMULATIONS THROUGH THE DAY.

MONDAY NIGHT...THE DRY AIR AND COLD TEMPERATURES AND CONTINUOUS
NORTHWEST WINDS REMAIN THROUGH 12Z, EXCEPT ON THE ECMWF WHERE
SYNOPTIC MOISTURE IS BEGINNING TO DESCEND INTO LAKE SUPERIOR AND IS
BEGINNING TO LINK UP WITH THE LAKE MOISTURE PLUME THAT IS PRODUCED
FROM THE -20 TO -21C AIR OVER LAKE SUPERIOR. WILL EXPECT THAT LIGHT
AMOUNTS WILL CONTINUE, BUT IF THE ECMWF IS RIGHT THEN MODERATE
AMOUNTS ARE POSSIBLE, MAINLY IN E UPPER.

(12/30)TUESDAY...ALL OF THE MODELS HAVE 850-700 MB SYNOPTIC MOISTURE
WITH -21C OR COLDER AIR. THE GFS AND NAM ARE SLOWER TO BRING IT OVER
N LOWER. THE ECMWF HAS THE MOISTURE OVER N LOWER AND E UPPER ALL DAY
LONG. SO LIGHT TO MODERATE ACCUMULATIONS ARE POSSIBLE AS THE WINDS
STAY WNW THROUGH THE DAY.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 359 PM EST SAT DEC 27 2014

TUESDAY NIGHT THROUGH WEDNESDAY: SURFACE HIGH PRESSURE CONTINUES TO
GRADUALLY SCOOT THROUGH THE WESTERN GREAT LAKES TUESDAY NIGHT INTO
WEDNESDAY. WHILE OVER THE LAKE INSTABILITY WILL REMAIN SUFFICIENT
(850 MB TEMPS OF -17C TO -21C) FOR CONTINUED LAKE EFFECT SNOW...A
LACK OF MOISTURE AND OVERALL SUBSIDENCE WILL LIKELY LIMIT ANY EYE-
POPPING SNOW ACCUMULATIONS DURING THIS PERIOD.

WEDNESDAY NIGHT THROUGH FRIDAY: DESPITE TIMING DIFFERENCES...SEVERAL
WEAK WAVES WILL PUSH THROUGH THE NORTHERN GREAT LAKES BRINGING A BIT
OF SYNOPTIC SUPPORT TO ANY LINGERING LAKE EFFECT SNOW DURING THIS
TIMEFRAME. NOTHING TOO MAJOR TO NOTE...BUT DEFINITELY CHANCES FOR
SNOW WILL CONTINUE.

SATURDAY: LOW CONFIDENCE IN TERMS OF THE OVERALL EVOLUTION OF A
SYSTEM THAT GETS EJECTED FROM THE SOUTHWESTERN CONUS DURING THE DAY
FRIDAY AND BEGINS TO MAKE ITS WAY ACROSS THE COUNTRY ON SATURDAY. AT
LEAST SOMETHING TO KEEP AN EYE ON AT THE VERY END OF THE PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 638 PM EST SAT DEC 27 2014

MAINLY MVFR...EXCEPT TRENDING VFR AT APN.

LOW PRESSURE IS NORTH OF LAKE HURON...MOVING RAPIDLY NE. COLD
FRONT SWEEPING ACROSS NE LOWER MI EARLY THIS EVENING. RAIN IS OR
WILL BE CHANGING TO SNOW...JUST BEFORE ENDING THIS EVENING. SOME
LIGHT LAKE EFFECT -SHSN WILL OCCUR VERY LATE TONIGHT INTO SUNDAY
NEAR PLN/TVC/MBL. THOUGH BRIEF AND VARIABLE IFR CONDITIONS ARE
POSSIBLE EARLY THIS EVENING...WE WILL SETTLE INTO MVFR CIGS AT
TVC/PLN/MBL...WITH VFR CONDITIONS AT APN.

W TO NW WINDS THRU THE FORECAST...A BIT BLUSTERY THIS EVENING.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 10 PM EST SUNDAY FOR LHZ345>348.

     SMALL CRAFT ADVISORY UNTIL 5 AM EST SUNDAY FOR LHZ349.

LM...SMALL CRAFT ADVISORY UNTIL 10 PM EST SUNDAY FOR LMZ342-344.

     SMALL CRAFT ADVISORY UNTIL 5 AM EST SUNDAY FOR LMZ323-345-346.

LS...SMALL CRAFT ADVISORY UNTIL 10 PM EST SUNDAY FOR LSZ321-322.

&&

$$

NEAR TERM...TJL
SHORT TERM...JSL
LONG TERM...GILLEN
AVIATION...JAZ


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