Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 162113
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
413 PM EST TUE DEC 16 2014

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 413 PM EST TUE DEC 16 2014

...RAIN CHANGES TO SNOW TONIGHT AS COLDER AIR FILTERS IN...

HIGH IMPACT WEATHER POTENTIAL: SOME ACCUMULATING WET SNOW
TONIGHT...MAINLY EASTERN UPPER/NORTHWEST LOWER MICHIGAN.  GUSTY
NORTHWEST WINDS FOR NORTHWEST/CENTRAL LOWER MICHIGAN TONIGHT.

PATTERN SYNOPSIS/FORECAST: 18Z SURFACE ANALYSIS SHOWS A 1004MB LOW
OVER FAR SOUTHEAST LOWER MICHIGAN...INVERTED TROUGH/COLD FRONT
EXTENDS FROM NORTHWEST QUEBEC INTO EASTERN UPPER MICHIGAN/NORTHERN
LAKE MICHIGAN WITH BELOW FREEZING TEMPERATURES ACROSS CENTRAL UPPER
MICHIGAN.  NEGATIVE TILT SHORT WAVE TROUGH EXTENDS SOUTHEAST FROM
LOWER MICHIGAN...A SECOND SMALL UPPER LOW WAS OVER NORTHERN
MINNESOTA.  RAIN SHOWERS WERE WRAPPING AROUND LOW/MID LEVEL
CIRCULATION CENTER OVER MICHIGAN...WITH SNOW ON THE BACK EDGE ACROSS
CENTRAL UPPER/NORTHEAST WISCONSIN.  SEPARATE AREA OF SNOW AHEAD OF
MINNESOTA UPPER LOW OVER FAR WESTERN UPPER/NORTHWEST WISCONSIN.
MORE DRIZZLY ACROSS NORTHERN LOWER WITH STRONGER FORCING ACROSS THE
NORTHERN HALF OF THE FORECAST AREA AND QG SUBSIDENCE ACROSS MUCH OF
CENTRAL/SOUTHERN LOWER.

SURFACE LOW WILL PULL AWAY INTO SOUTHERN ONTARIO THIS EVENING...
ALLOWING WINDS TO PICK UP FROM THE NORTHWEST AND BRING COLDER
TEMPERATURES BACK INTO NORTHERN MICHIGAN.  MINNESOTA UPPER LOW WILL
ELONGATE TO THE SOUTHEAST TONIGHT...RESULTING IN A STRETCHED OUT
POTENTIAL VORTICITY ANOMALY FROM THE DAKOTAS EAST-SOUTHEAST INTO
SOUTHERN LOWER MICHIGAN.

PRIMARY FORECAST CONCERNS: ONGOING PRECIPITATION TRANSITIONING FROM
LIQUID TO FROZEN...AND POTENTIAL SNOWFALL AMOUNTS TONIGHT.

TONIGHT: EXPECTING THE MOST SIGNIFICANT PRECIPITATION TONIGHT TO
OCCUR ACROSS THE NORTHERN HALF OF THE FORECAST AREA...THOUGH EXPECT
ALL AREAS TO EVENTUALLY GET IN ON SOME MEASURABLE PRECIPITATION.
PRECIPITATION WILL STILL BE RAIN AT FORECAST ISSUANCE...WITH
EXPECTATION OF A CHANGEOVER TO SNOW ACROSS EASTERN UPPER AND
SOUTHWEST PORTION OF THE FORECAST AREA DURING EARLY-MID
EVENING...THEN ACROSS THE REMAINDER OF NORTHWEST LOWER DURING MID-
LATE EVENING...AND NORTHEAST LOWER OVERNIGHT.  BEST SNOW
ACCUMULATION EXPECTED ACROSS EASTERN UPPER MICHIGAN GIVEN
COMBINATION OF HIGHEST QPF AND LONGEST DURATION OF SNOWFALL.  EXPECT
FAIRLY LOW/WETTER SNOW RATIOS TONIGHT...WITH MUCH OF THE UPWARD
FORCING CONFINED TO LOWER LEVELS/WARMER TEMPERATURES (MORE
SUPPORTIVE OF ACCRETION/RIMING AND NOT DENDRITIC GROWTH).  HAVE
PAINTED A SWATH OF 1-2+ INCHES ACROSS EASTERN UPPER/TIP OF THE MITT
TONIGHT...AROUND AN INCH ACROSS HIGHER TERRAIN OF NORTHWEST
LOWER...AND LITTLE ACCUMULATION OVER NORTHEAST LOWER.  EXPECT WINDS
TO BECOME GUSTY THIS EVENING ACROSS THE SOUTHWEST HALF OF THE
FORECAST AREA WITH COMBINATION OF STRONGER GRADIENT AND COLD
ADVECTION/DOWNWARD MOMENTUM MIXING.  WIND GUSTS OF 20-30MPH
EXPECTED STARTING THIS EVENING.

&&

.SHORT TERM...(WEDNESDAY THROUGH FRIDAY)
ISSUED AT 413 PM EST TUE DEC 16 2014

...MORE TYPICAL DECEMBER WEATHER...

HIGH IMPACT WEATHER POTENTIAL: SOME ACCUMULATING SNOW...ESPECIALLY
FOR EASTERN UPPER AND THE MORE TRADITIONAL SNOW BELTS OF NORTHERN
LOWER MICHIGAN WEDNESDAY.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: ACTIVE SPLIT FLOW PATTERN TO
START THE EXTENDED...WITH STRONG NORTHERN STREAM ENERGY SET TO CROSS
THE STATE WEDNESDAY. THIS WILL USHER IN CONDITIONS MUCH MORE
FAMILIAR TO NORTHERN MICHIGAN RESIDENTS FOR MID-DECEMBER...WITH
TEMPERATURES RETURNING TO NEAR NORMAL LEVELS AND PERIODS OF MOSTLY
LIGHT SNOW. WEATHER TURNS DECIDEDLY QUIETER TO END THE WEEK AS HIGH
PRESSURE BUILDS ACROSS THE UPPER MIDWEST.

PRIMARY FORECAST CHALLENGES/CONCERNS: MAIN FOCUS TIED TO SNOW
ACCUMULATIONS WEDNESDAY. TEMPERATURE/CLOUD TRENDS AND ENDING OF
LIGHT LAKE ENHANCED SNOWS ALSO NEED ADDRESSING.

DETAILS: DECAYING DEFORMATION/SURFACE CONVERGENCE DRIVEN SNOWS
EXPECTED TO BE FAIRLY WIDESPREAD ACROSS THE AREA WEDNESDAY AS
NORTHERN STREAM ENERGY SHEARS OUT THROUGH THE REGION. LAKE
CONTRIBUTIONS CONTINUE TO LOOK MINIMAL...WITH VERY MARGINAL
THERMODYNAMIC SIGNATURES VIA LESS THAN STELLAR DELTA T/S AND SUB 5KT
INVERSION LEVELS. CBL BARELY REACHES FAVORABLE DGZ (IF AT ALL) WITH
INTERSECTION OF DEEPEST MOISTURE/DGZ WAY UP IN THE MID LEVELS.
SNOW/LIQUID RATIOS RATHER LOW AS A RESULT...AND GIVEN OTHER LIMITED
FACTORS DISCUSSED ABOVE...STILL THINK ANY ADDITIONAL SNOW
ACCUMULATIONS WILL LARGELY REMAIN UNDER 2 INCHES...WITH FAR LESS
AMOUNTS AS ONE GOES TOWARD SAGINAW BAY. SUPPORT CONTINUES TO WANE
HEADING THROUGH WEDNESDAY NIGHT...WITH WARMING OFF THE DECK PROFILES
FURTHER LIMITING ANY LAKE CONTRIBUTIONS. WILL TREND ALREADY LOW SNOW
AMOUNTS DOWN THROUGH THE OVERNIGHT...TENDING TO BELIEVE ANYTHING
THAT FALLS WILL BE MOSTLY FLURRIES. EVEN THE POSSIBILITY OF A TOUCH
OF FREEZING DRIZZLE AS WE HEAD THROUGH THE OVERNIGHT AS MID LEVEL
MOISTURE CONTINUES TO THIN OUT. WILL NOT GO THIS DIRECTION JUST
YET...BUT SOMETHING TO MONITOR FOR SURE.

ANY LINGERING FLURRIES END QUICKLY THURSDAY MORNING...WITH CROSS
SECTION MOISTURE ANALYSIS EVEN SHOWING A STEADY EROSION OF CLOUDS
FROM NORTH TO SOUTH AS DRY AIR ADVECTION STRENGTHENS. CLEARING
CONTINUES THURSDAY NIGHT...LEADING TO A MOSTLY SUNNY FRIDAY.

TEMPERATURES: BACK TO REALITY...WITH HIGHS WEDNESDAY THROUGH FRIDAY
MOSTLY IN THE UPPER 20S AND LOWER 30S.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 413 PM EST TUE DEC 16 2014

FRIDAY NIGHT THROUGH SUNDAY: SURFACE HIGH PRESSURE DOMINATES THIS
TIMEFRAME LEADING TO GENERALLY QUIET CONDITIONS WITH TEMPERATURES
NEAR OR EVEN A FEW DEGREES ABOVE NORMAL. THE ONLY EXCEPTION MAY BE A
WEAK WAVE THAT QUICKLY PUSHES THROUGH THE OHIO VALLEY SATURDAY
NIGHT. IF THE EXTREME NORTHERN END OF THE PRECIP WERE TO SNEAK INTO
FAR SOUTHEASTERN COUNTIES...THIS COULD RESULT IN FLURRIES AT BEST...
BUT WILL KEEP IT DRY AREA-WIDE AS CHANCES FOR THIS REMAIN LOW.

SUNDAY NIGHT THROUGH TUESDAY: BY SUNDAY NIGHT...HIGH PRESSURE BEGINS
TO SLOWLY SLIDE TOWARD THE NORTHEAST. THIS EASTWARD PROGRESSION WILL
BE AIDED BY THE APPROACH OF A DEVELOPING LOW PRESSURE SYSTEM
ORIGINATING OUT OF ALBERTA THAT QUICKLY DIVES INTO GREAT PLAINS BY
MONDAY. THIS ENERGY WILL STRENGTHEN AND SHIFT ITS FOCUS INTO THE
GREAT LAKES LATE MONDAY INTO TUESDAY.

WHILE CONFIDENCE IS INCREASING REGARDING THE POTENTIAL FOR THE
RETURN OF ACTIVE WEATHER TOWARD THE END OF THIS PERIOD (BEGINNING TO
MIDDLE OF NEXT WEEK)...THE TRACK AND OVERALL STRENGTH OF THE
SYSTEM(S) HAS YET TO BE NAILED DOWN. BY THE CURRENT LOOK OF
IT...WITH THE LOW PRESSURE CENTER MOVING NORTHWEST OF THE CWA...NO
DOUBT PRECIP TYPE COULD PRESENT A CHALLENGE WITH A MIXED BAG
POSSIBLE ACROSS THE FORECAST AREA DEPENDING ON LOCATION AND
TIMING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1256 PM EST TUE DEC 16 2014

MOSTLY IFR/MVFR CONDITIONS WILL PREVAIL THROUGH TONIGHT...AS
COLDER AIR ARRIVES AND RAIN CHANGES OVER TO SNOW.

&&

.MARINE...
ISSUED AT 413 PM EST TUE DEC 16 2014

SMALL CRAFT ADVISORIES UP FOR NORTHWEST LOWER NEARSHORE ZONES
THROUGH TOMORROW...AS WINDS PICK UP BEHIND DEPARTING SURFACE LOW.
WIND GUSTS TO 30 KNOTS EXPECTED ALONG WITH AN INCREASE IN WAVE
HEIGHTS.  WINDS WILL SUBSIDE A LITTLE WEDNESDAY NIGHT.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST WEDNESDAY FOR
      LMZ342-344>346.

LS...NONE.
&&

$$

NEAR TERM...JPB
SHORT TERM...MSB
LONG TERM...GILLEN
MARINE...JPB


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