Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 290800
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
300 AM EST MON DEC 29 2014

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 258 AM EST MON DEC 29 2014

...MOSTLY LIGHT LAKE INDUCED SNOWS TO CONTINUE...

HIGH IMPACT WEATHER POTENTIAL: SIMPLY NOT MUCH. STILL LOOKING AT
SOME LIGHT SNOW ACCUMULATIONS...PARTICULARLY ACROSS THE EASTERN UPPER
SNOW BELTS.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: MUCH ADVERTISED RETURN TO A
COLDER WEATHER PATTERN WELL UPON US...COURTESY OF AN INCREASINGLY
AMPLIFIED NAMERICA PATTERN FEATURING PROMINENT FAR EAST PACIFIC
RIDGING AND SUBSEQUENT BROAD TROUGHING LAYING OUT ACROSS MUCH OF THE
CONUS. WHILE INITIAL SURGE OF COLD AIR HAS BEEN SOMEWHAT
MUTED...MUCH MORE IMPRESSIVE SURGE OF MODIFIED ARCTIC AIR ABOUT
READY TO MAKE ITS PRESENCE FELT HEADING THROUGH THE MID WEEK PERIOD.
SIMPLE MAGNITUDE OF COOLING AND STILL WIDE OPEN GREAT LAKES
RESULTING IN RATHER WIDESPREAD LIGHT SNOW SHOWER AND FLURRIES...THE
INTENSITY OF WHICH HAS BEEN GREATLY REGULATED BY LIMITED SYNOPTIC
SUPPORT AND AN OVERALL DRY AIRMASS. DESPITE FURTHER COOLING...
OVERALL FLAVOR OF THE FORECAST CHANGES LITTLE IN THE COMING
DAYS...WITH PERSISTENT MOSTLY LIGHT LAKE SNOWS TARGETING THE
TRADITIONAL SNOW BELTS.

PRIMARY FORECAST CHALLENGES/CONCERNS: LAKE EFFECT SNOW
COVERAGE...LOCATION...AND AMOUNTS TODAY AND TONIGHT.

DETAILS: A RATHER PURE LAKE EFFECT PATTERN WILL PERSIST THROUGH
TONIGHT. SYNOPTIC SUPPORT WILL REMAIN MINIMAL...CONFIRMED BY
UPSTREAM SATELLITE/SURFACE ANALYSIS SHOWING PLENTY OF DRY AIR SET TO
ROTATE SOUTHEAST ACROSS THE LAKES.

LAKE SUPERIOR: MATURATION OF LAKE AGGREGATE TROUGHING AND SIMPLE 150+
MILE FETCH LENGTH WILL DEFINITELY HELP THE SNOW PRODUCING CAUSE FOR
THE SNOW BELTS OF EASTERN UPPER MICHIGAN. DESPITE DURATION OF LAKE
MODIFICATION...CONVECTIVE BOUNDARY LAYER DEPTH REMAINS
LIMITED...GENERALLY AT OR BELOW 5 KFT. WHILE INVERSION LEVEL
TEMPERATURES ACTUALLY BECOME TOO COLD FOR DENDRITIC FLAKE GROWTH
...ENTIRE CLOUD DEPTH AND WEAK OMEGA PROFILE DO NOT...SUGGESTING
REASONABLY HIGH SNOW/LIQUID RATIOS TO CONTINUE. FLOW PATTERN REMAINS
LARGELY ROCK-STEADY OUT OF THE WNW...WITH SNOW SHOWERS REMAINING
MOST PERSISTENT ALONG AND NORTH OF THE M-28 CORRIDOR. ALL
TOLD...COULD SEE ANOTHER 2 TO 5 INCHES IN THE FAMED SNOW BELTS OF
NORTHERN CHIPPEWA COUNTY (INCLUDING SAULT STE MARIE) BY SUNRISE
TUESDAY...WITH PERHAPS SOME LOCALLY HIGHER AMOUNTS POSSIBLE SIMPLY
DUE TO PERSISTENCE OF ACTIVITY.

LAKE MICHIGAN: MUCH OF THE THERMODYNAMIC/KINEMATIC PROFILES OFF
NORTHERN LAKE MICHIGAN JUST DOWNRIGHT HOSTILE THROUGH THE
PERIOD...WITH NO SOURCE OF FOCUSED LOW LEVEL CONVERGENCE TO OFFSET
SHORT FETCH LENGTH...NO LARGE SCALE MOISTURE CONTRIBUTION...AND A
CONVECTIVE BOUNDARY LAYER EXPECTED TO REMAIN SUB 4KFT. CLOUD BEARING
LAYER WITHIN THE DGZ AND SIMPLE MAGNITUDE OF WATER/AIR TEMPERATURE
DIFFERENCE SHOULD KEEP SOME VERY LIGHT ACTIVITY TARGETING THE WNW-NW
FLOW FAVORED AREAS. REALLY STARTING TO THINK THIS WILL ESSENTIALLY
BE A NON-EVENT FOR NORTHWEST LOWER...WITH WIDESPREAD
FLURRIES/INTERMITTENT VERY LIGHT SNOW SHOWERS BRINGING LITTLE IN THE
WAY OF ANY DECENT ACCUMULATION. WILL FURTHER LOWER ALREADY MINOR
INHERITED SNOWFALL AMOUNTS...THINKING THOSE AREAS TARGETED BY THE
MOST PERSISTENT SNOW SHOWERS WILL SEE LITTLE MORE THAN A DUSTING BY
TUESDAY MORNING.

AS ALWAYS IN SUCH CASES...CLOUD COVERAGE REMAINS A FORMIDABLE
CHALLENGE...ESPECIALLY AWAY FROM THE LAKE BELTS (SEE YESTERDAY`S
SURPRISE CLEARING DURING THE MORNING). STILL THINKING MORE CLOUDS
THAN SUN...WITH LAKE INDUCED MOISTURE HAVING A HARD TIME MIXING OUT
UNDER SUBSIDENCE INVERSION. AS FOR TEMPERATURES...EXPECT HIGHS TODAY
MOSTLY IN THE LOWER AND MIDDLE 20S...WITH LOWS TONIGHT GENERALLY IN
THE TEENS.

&&

.SHORT TERM...(TUESDAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 258 AM EST MON DEC 29 2014

TUESDAY AND WEDNESDAY...STRONG SURFACE RIDGE AXIS OVER MICHIGAN AT
12Z TUESDAY WILL SLOWLY DROP SOUTH INTO THE OHIO VALLEY BY TUESDAY
NIGHT. AS THE SURFACE HIGH BUILDS FURTHER SOUTH INTO THE SE US...
BROAD UPPER LEVEL TROUGHING WILL DIG INTO THE GREAT LAKES REGION.
THIS PATTERN EVOLUTION WILL SERVE TO REINFORCE THE COLD AIRMASS
OVERHEAD...MAINTAINING 850 MB TEMPS A FEW DEGREES EITHER SIDE OF -20
C FOR TUESDAY AND WEDNESDAY. DESPITE ABUNDANT OVER-LAKE
INSTABILITY...LAKE SNOW ACCUMULATION POTENTIAL WILL BE LIMITED BY
RELATIVELY LOW INVERSION HEIGHTS OF 4-5 KFT AND VIRTUALLY NO
MOISTURE AVAILABLE ABOVE THE INVERSION FOR ENHANCEMENT. W/NW WINDS
TUESDAY WILL SHIFT TO THE WEST LATE TUESDAY NIGHT AND THEN TO THE
W/SW ON WEDNESDAY AHEAD OF A WAVE SWINGING THRU THE BASE OF THE
BROAD UPPER LEVEL TROUGH. THUS...THE TYPICAL SNOWBELT REGIONS OF ERN
UPR AND NW/N CENTRAL LWR MICHIGAN WILL CONTINUE TO BE TARGETED FOR
THE HIGHEST POPS AND GREATEST POTENTIAL OF ACCUMULATIONS. NEW SNOW
ACCUMULATIONS WILL CONTINUE TO BE LIGHT...EXPECTING AN INCH OR LESS
FOR EACH FORECAST PERIOD THRU WEDNESDAY. HIGH TEMPS BOTH TUESDAY AND
WEDNESDAY WILL ONLY WARM INTO THE TEENS...WITH LOW TEMPERATURES BOTH
NIGHTS IN THE SINGLE DIGITS ABOVE ZERO TO THE LOW TO MID TEENS.

&&

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 258 AM EST MON DEC 29 2014

BROAD UPPER LEVEL TROUGHING WILL REMAIN IN
PLACE ACROSS THE GREAT LAKES REGION LATE THIS WEEK AND THRU THE
WEEKEND. OVER-LAKE INSTABILITY WILL BE MORE THAN SUFFICIENT FOR
CONTINUED LAKE SNOW PRODUCTION...PERIODICALLY ENHANCED BY A SERIES
OF SHORT WAVES RIDING THRU THE BASE OF THE BROAD TROUGH. HIGH TEMPS
WILL BE MAINLY IN THE 20S THRU THIS TIME PERIOD...WITH OVERNIGHT
LOWS GENERALLY IN THE TEENS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1216 AM EST MON DEC 29 2014

NOT MUCH CHANGE WITH LAKE AUGMENTED LOW LEVEL MOISTURE REMAINING
STUCK UNDER STRONG INVERSION. MAINLY VFR/MVFR STRATO-CU EXPECTED
RIGHT THROUGH THIS TAF CYCLE...WITH NON-VIS RESTRICTING
FLURRIES/VERY LIGHT SNOW SHOWERS EXPECTED AT THE WESTERN TAF
LOCATIONS. LIGHT WEST TO NORTHWEST WINDS WILL PREVAIL.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR LHZ347-
 348.
LM...NONE.
LS...NONE. &&

$$

NEAR TERM...MSB
SHORT TERM...MLR
LONG TERM...MLR
AVIATION...MSB



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