Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 171733
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1233 PM EST WED DEC 17 2014

.UPDATE...
ISSUED AT 1145 AM EST WED DEC 17 2014

LIGHT SNOW CONTINUES TO FALL ACROSS MOST OF NORTHERN MICHIGAN AT
MIDDAY...IN THE WAKE OF A 1007MB SURFACE LOW OVER SOUTHEAST
ONTARIO WITH A THERMALLY INDUCED TROUGH EXTENDING BACK ACROSS
UPPER MICHIGAN. EXPECT THIS TO CONTINUE INTO THE AFTERNOON WITH
DECENT BUT SHALLOW UPWARD FORCING. SOME ENHANCEMENT IN NORTHWEST
FLOW OFF LAKE MICHIGAN...THOUGH OVERALL ACCUMULATIONS DURING THE
AFTERNOON HOURS WILL BE ON THE LIGHT SIDE. TEMPERATURES NOT LIKELY
TO MOVE VERY FAR THIS AFTERNOON.

&&

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 400 AM EST WED DEC 17 2014

FORECAST CHALLENGES: SNOW AMOUNTS/SNOW ENDING

OVERVIEW...CUTOFF LOW IN THE UPPER GREAT LAKES IS CONTINUING ITS
PATH INTO S LOWER AS THE SFC LOW MOVES NE INTO QUEBEC. THIS HAS
ALLOWED THE COLDER AIR TO MOVE INTO THE FORECAST AREA, CHANGING THE
RAIN INTO SNOW E UPPER, NC LOWER, AND NW LOWER. NE LOWER IS STILL
REPORTING RAIN OR FOG.

TODAY...MODEL EVOLUTION OF THE 500 MB LOW IS TO TRANSFER THE CORE OF
THE LOW FROM WISCONSIN TO ONTARIO, AS THE TROUGH AXIS ROTATES INTO S
LOWER AT THE SAME TIME, THE 700-500 MB LAYER FALLS TO 20% JUST SOUTH
OF M-55. THIS INITIALLY, GAVE A GLIMMER OF HOPE TO SEEING SOME
SUNSHINE, BUT THE 850 MB RH>90% AND WITH THE COLDER AIR (850 MB T
AROUND -10C) FOLLOWING THE 500 MB LOW, THE CLOUD DEPTH ON THE MODEL
SOUNDINGS CONTINUE TO SHOW ENOUGH MOISTURE UP TO -10C SO THAT ICE
PRODUCTION CONTINUES, AND THE THREAT OF DRIZZLE SHOULD REMAIN LOW.
SO THE MAIN CONCERN IS THAT WITH THE COLDEST AIR MOVING ACROSS N
LOWER AND WITH SOME FORCING THERE SNOW WILL CONTINUE OVER THE
FORECAST AREA, MAINLY NORTH OF M-72, AND ESPECIALLY NORTH OF M-32.
BASED ON THE CURRENT RADAR, THE ROTATION OF THE 500 MB LOW AND THE
SNOW ASSOCIATED WITH IT WILL CONTINUE NORTH OF M-32 AND IN E UPPER.
IT DOESN`T LOOK LIKE THE COLDEST TEMPERATURES AT 850 MB DON`T END UP
OVER N LAKE MICHIGAN, SO WON`T EXPECT ANY LAKE ENHANCEMENT AT THIS
TIME. THIS LEADS TO LIGHT ACCUMULATIONS FOR THE DAY.

TONIGHT...AS THE 500 MB LOW MOVES EAST AND THE MAIN CORE OF THE LOW
AND THE TROUGH AXIS ARE OUT OF THE FORECAST AREA, THE FORCING LEFT
OVER (LAKE AGGREGATE SFC TROUGH)IS THE ONLY FORCING AS THE
INSTABILITY (DELTA TS ARE ABOUT 10C TO 11C) IS STILL WEAK SO WILL
EXPECT THAT THE SNOW WILL BECOME SPOTTY AS THE LOW CONTINUES EAST.
INHERITED A GOOD DEAL OF FLURRIES FOR THE LATE EVENING AND EARLY
MORNING, THINK THAT WITH THE WEAK FORCING AND THE 700-500 MB LAYER
RH DROPPING, THAT FLURRIES ARE A GOOD BET THROUGH A PORTION OF THE
NIGHT.

&&

.SHORT TERM...(THURSDAY THROUGH FRIDAY)
ISSUED AT 400 AM EST WED DEC 17 2014

...BACK TO NORMAL...

PATTERN DESCRIPTION AND EVOLUTION:

UPPER LEVEL LOW PRESSURE WILL BE OVER NEW ENGLAND THURSDAY...WITH
WEAK FLOW ALOFT COMMON INTO FRIDAY AS RIDGING BOTH ALOFT AND AT
THE SFC SETTLES IN OVER THE GREAT LAKES. THERE WILL BE SOME WEAK
TROUGHING THAT NEARS NORTHERN MICHIGAN LATER FRIDAY...BUT IT`S
INSIGNIFICANT.

FORECAST CHALLENGES: TIMING AND EVOLUTION OF CLEARING SKIES...AND
SUBSEQUENT TEMPERATURE ISSUES.

ASSOCIATED WEATHER:

THURSDAY THROUGH FRIDAY: THE UPPER LEVEL LOW PRESSURE WILL HAVE SOME
MID LEVEL AND SFC TROUGHING EXTENDING BACK ACROSS THE GREAT LAKES
EARLY THURSDAY. THERE IS ALSO SOME POTENTIAL MID LEVEL MOISTURE THAT
COULD BE STILL TRYING TO VACATE NRN LOWER EARLY THURSDAY...BUT WE
WILL BE SEEING DEEP LAYER DRYING ONGOING THROUGH THE DAY...THIS WILL
ESPECIALLY BE TRUE ACROSS EASTERN UPPER WITH NNE FLOW DOWNSLOPING
OUT OF ONTARIO. THERE ARE SIGNS THAT THIS DRYING WILL NOT BE AS
AGGRESSIVE ACROSS NRN LOWER IN FAIRLY WEAKISH BL FLOW...WITH THE LOW
LEVELS STILL SEEING TRAPPED SHALLOW MOISTURE (GO FIGURE). THIS COULD
LINGER INTO MUCH/ALL OF THURSDAY NIGHT (AND EVEN FRIDAY MORNING)
WITH EFFICIENT BL COOLING (ANOTHER GO FIGURE). CROSS YOUR FINGERS
HERE...BUT WE SHOULD SEE ANY STRATUS THAT IS AROUND FRIDAY
MORNING...TO ERODE THROUGH THE DAY...SO THAT WE CAN GET THAT SUN TO
SHINE. HOPEFULLY A WEAK UPPER LEVEL WARM FRONT (FROM THE WEAK
TROUGHING MENTIONED ABOVE) WILL NOT BRING ANY SIGNIFICANT CLOUD
COVER...OF WHICH...IT`S NOT ATTM. STILL EXPECTING GOOD SUN.

OUTSIDE OF SOME POSSIBLE FLURRIES ALONG THE NRN LOWER NORTHERLY FLOW
REGIMES...PRECIPITATION IS OUT OF THE QUESTION THURSDAY AND FRIDAY.

HIGH TEMPERATURES WILL BE IN THE MID AND UPPER 20S THURSDAY...WITH
ONLY A DEGREE OR TWO RISE FRIDAY. LOWS MAY NEED TO COME UP
SIGNIFICANTLY IN NRN LOWER THURSDAY NIGHT IF THE STRATUS IS
AROUND...AND I AM LEANING THAT WAY...SO 10-15F MOST OF EASTERN
UPPER...WITH UPPER TEENS AND LOWER 20S IN NRN LOWER.

&&

.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 THURSDAY AFTERNOON)
ISSUED AT 1232 PM EST WED DEC 17 2014

PERIODS OF MOSTLY LIGHT SNOW WILL CONTINUE THIS AFTERNOON...THOUGH
COULD BE BURSTS OF HEAVIER SNOW/IFR VISIBILITIES AT TVC THROUGH
22Z WITH ENHANCEMENT OF SNOWFALL OFF LAKE MICHIGAN. SNOW EXPECTED
TO WIND DOWN IN COVERAGE AND INTENSITY BY LATE AFTERNOON/EARLY
EVENING.

&&

.MARINE...
ISSUED AT 400 AM EST WED DEC 17 2014

WIND WILL INCREASE THIS MORNING ON ALL THE LAKES AS THE SFC LOW
MOVES TO THE EASY AND THE GRADIENT ON THE BACK SIDE OF THE LOW
TIGHTENS UP. WILL EXPECT SMALL CRAFT GUSTS ON THE N TO NW WINDS
THROUGH THE EVENING, THEN THE GRADIENT BEGINS TO RELAX OVERNIGHT
AND WILL EXPECT THAT THE WINDS WILL DIMINISH ENOUGH FOR THE GUSTS
TO DROP TO BELOW 15 KNOTS. AS THE SFC HIGH BUILDS INTO THE REGION
THURSDAY AND THURSDAY NIGHT, WILL EXPECT THE WINDS WILL DROP BELOW
10 KNOTS.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 AM EST THURSDAY FOR LMZ323-342-
     344>346.

LS...NONE.
&&

$$

UPDATE...JPB
NEAR TERM...JSL
SHORT TERM...SMD
LONG TERM...GILLEN
MARINE...JSL


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