Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 180714
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
214 AM EST THU DEC 18 2014

.UPDATE...
ISSUED AT 1115 PM EST WED DEC 17 2014

VERY LIGHT SNOWS WERE ONGOING ACROSS PRETTY MUCH ALL OF NRN
MICHIGAN...UNTIL A SOLID CHUNK OF DRY AIR/SUBSIDENCE BETWEEN
850MB AND 700MB SHUT THAT DOWN OVER ALL AREAS OUTSIDE OF THE NW
FLOW LAKE EFFECT REGIMES. LAKE EFFECT SNOW SHOWERS ARE STILL
ONGOING IN THOSE REGIMES...BUT THAT SAME DRY AIR WILL SEVERELY
LIMIT THEIR ABILITY TO REDUCE VSBYS...AND CERTAINLY ACCUMULATIONS.

CUT EXPECTED ACCUMULATIONS DOWN TO A TENTH OR TWO IN THE NW/N FLOW
REGIMES.

&&

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 212 AM EST THU DEC 18 2014

...SUNSHINE...

SYNOPTIC PATTERN AND OBSERVATIONS:

UPPER AND SFC LOWS ARE IN NEW ENGLAND EARLY THIS MORNING...WITH WEAK
FLOW/MID LEVEL RIDGING SLOWLY WORKING IN OVER NRN MICHIGAN. STRONG
COMPRESSIONAL WARMING/DRYING HAS ALREADY SCOURED OUT MUCH OF THE
MOISTURE THAT HAS BEEN LINGERING BACK ALONG RESIDUAL LOW TO MID
LEVEL TROUGHING. THIS SQUASHED THE SNOWS AROUND MIDNIGHT...AND ONLY
LEFT SOME WEAK/VERY LIGHT LAKE EFFECT IN NNW/NORTH FLOW REGIMES. WE
ARE EVEN SEEING THIS SNOW GET SEVERELY WEAKENED OVER THE LAST FEW
HOURS. THE STRONGEST PUSH OF THE DRIER AIR IS RIGHT INTO NRN
MICHIGAN...AND IS SEEN VIA LATEST SATELLITE...WITH CLEARING ALREADY
PUNCHING THROUGH EASTERN UPPER AND EVEN PARTS OF FAR NRN LOWER. THIS
IS IN CONTRAST TO WISCONSIN AND PARTS OF FAR WESTERN UPPER WHERE THE
STRATUS IS ACTUALLY EXPANDING WEST/NW OVERNIGHT. THE CLEARING SKIES
AND WEAKENING WINDS HAVE ALLOWED TEMPERATURES TO FALL INTO THE TEENS
ACROSS IN EASTERN UPPER.

SYNOPTIC PATTERN EVOLUTION AND ASSOCIATED WEATHER:

NOT MUCH TO TALK ABOUT. THE LOWER LEVEL TROUGHING/CONVERGENCE SLOWLY
DROPS SOUTH TODAY...WHILE MID LEVEL RIDGING AND STRONGER SFC HIGH
PRESSURE NEARS. LATEST SATELLITE AND DATA SUGGEST NOTHING TO STOP
THIS STRONGER PUSH OF DRYING AIR. THUS...SKIES WILL CLEAR THROUGH
THE DAY. THIS WILL TAKE LONGEST IN THE NORTHERLY FLOW REGIMES WHERE
CONTINUED OVERLAKE INSTABILITY HELP FEED OFF THE LAKES. THAT
SAID...WEAKENING WINDS THROUGH THE DAY WILL CONTINUALLY MINIMIZE ANY
MOISTURE FLUX OFF THE WATER. CLEAR SKIES FOR THE NIGHT...WITH EVEN
THE NORTHERLY FLOW REGIMES SEEING MOSTLY CLEAR CONDITIONS. THE LIGHT
WINDS AND CLEAR SKIES WILL ALLOW TEMPERATURES TO FALL INTO THE
SINGLE DIGITS TO TEENS ACROSS PRETTY MUCH ALL OF NRN MICHIGAN.

&&

.SHORT TERM...(THURSDAY THROUGH SATURDAY)
ISSUED AT 407 PM EST WED DEC 17 2014

...QUIET AND COOL...

HIGH IMPACT WEATHER POTENTIAL: NONE.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: PATTERN REMAINS FAIRLY
PROGRESSIVE...ALLOWING UPSTREAM DEEP LAYER RIDGING TO BUILD OVERHEAD
TO END THIS WEEK. RELATIVELY LOW AMP WAVE FOLLOWS FOR THE
WEEKEND...ALTHOUGH WITH A TOTAL DISCONNECT BETWEEN IT AND GULF
MOISTURE PLUME PLOWING THROUGH THE SOUTHEASTERN STATES. ALL IN
ALL...A FAIRLY BENIGN PATTERN (AT LEAST FOR NOW).

PRIMARY FORECAST CHALLENGES/CONCERNS: CLOUD TRENDS THROUGH THURSDAY
NIGHT. TEMPERATURE TRENDS THROUGH THE PERIOD.

DETAILS: AS MENTIONED...RATHER DEEP LAYER HIGH PRESSURE BUILDS
STEADILY OVERHEAD THURSDAY...EVENTUALLY CENTERING ITSELF ACROSS THE
AREA ON FRIDAY. MODEL SOUNDINGS/CROSS-SECTION MOISTURE ANALYSIS
CONTINUES TO SUPPORT LOW CLOUDS HANGING ON FOR MUCH OF NORTHERN
LOWER THURSDAY...WITH COOLING BOUNDARY LAYER AND STRONG SUBSIDENCE
INVERSION LOCKING IN STRATUS THROUGH MUCH OF THURSDAY NIGHT.
FORECAST ALREADY LARGELY TRENDED THIS DIRECTION BY PREVIOUS
FORECASTER...AND SIMPLY CAN FIND NO COMPELLING ARGUMENT AGAINST IT.
DEEP LAYER DRYING NORTH OF THE BIG BRIDGE SUPPORTS PLENTY MORE SUN
UP THAT WAY...WITH THIS CLEARING EVENTUALLY SPREADING SOUTH DURING
THE DAY FRIDAY. RIDGE DEPARTS FOR THE WEEKEND...REPLACED BY A
COMPLETELY MOISTURE AND DYNAMICALLY STARVED TROUGH AXIS. OTHER THAN
PERHAPS SOME INCREASING HIGH/MID CLOUDS...JUST NOT SEEING MUCH
OPPORTUNITY FOR ANY PRECIPITATION WITH THIS FEATURE.

TEMPERATURES: NEAR SEASONAL READINGS FOR THIS TIME OF THE
YEAR...WITH HIGHS GRADUALLY MODERATING FROM THE MID 20S/LOWER 30S
THURSDAY TO THE LOWER/MID 30S BY SUNDAY. OVERNIGHT LOWS MOSTLY IN
THE TEENS AND 20S.

&&

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 407 PM EST WED DEC 17 2014

SATURDAY NIGHT THROUGH SUNDAY: FAIRLY QUIET DURING THIS PERIOD AS
HIGH PRESSURE GRADUALLY PUSHES TOWARD THE EAST COAST.

SUNDAY NIGHT THROUGH WEDNESDAY: GOOD AGREEMENT THAT A WEAK WAVE OF
LOW PRESSURE WILL BEGIN TO DIVE SOUTHEASTWARD OUT OF
CANADA...BECOMING CENTERED OVER THE DAKOTAS SUNDAY NIGHT. AS THIS
FEATURE DOES SO...THERE IS A SLIGHT CHANCE WE SEE A SHOT OF LIGHT
WARM AIR ADVECTION SNOW LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING
OVER THE NORTHWESTERN THIRD OF THE CWA...BUT NOT MUCH EXPECTED IN
THE WAY OF IMPACTS AS SNOW AMOUNTS WOULD REMAIN MINOR.

MORE IMPRESSIVELY DURING THE DAY ON MONDAY...A 160-180 KT PACIFIC JET
BEGINS TO DIVE FROM THE PACIFIC NORTHWEST INTO THE CENTRAL
ROCKIES...AIDING IN DIGGING AN IMPRESSIVE TROUGH INTO THE SOUTHERN
CONUS BY TUESDAY MORNING. AS ENERGY ROUNDS THE BASE OF THE TROUGH
TUESDAY NIGHT...THE TROUGH BECOMES NEGATIVELY TILTED BY WEDNESDAY
MORNING AND CONTINUES TO STRENGTHEN AS REFLECTED BY THE DEEPENING
~970 MB SURFACE LOW MOVING FROM THE OHIO VALLEY INTO THE THUMB/FAR
SOUTHERN ONTARIO DURING THE DAY ON WEDNESDAY.

IN TERMS OF LOCAL IMPACTS...THERE IS FAIRLY DECENT AGREEMENT THAT
DESPITE TIMING DIFFERENCES IN TERMS OF THE PRECIP ARRIVAL THAT 850
MB TEMPERATURES WILL REMAIN BELOW 0C FOR MUCH OF THE EVENT.
HOWEVER...PRECIP COULD FALL AS RAIN FOR A PORTION OF THE EVENT AS
925 MB AND SFC TEMPS REMAIN ABOVE FREEZING BEFORE THE LOW PUSHES
NORTH WELL INTO CANADA ALLOWING FOR COLD AIR TO SURGE INTO THE AREA.
THIS PUSH OF COLD AIR MAY NOT OCCUR IN FULL FORCE UNTIL TOWARD THE
VERY TAIL END OF THE PERIOD & BEYOND. WITH THIS BEING SAID AND
FAIRLY GOOD MODEL CONSISTENCY OF A DEVELOPING SYSTEM OVER THE
EASTERN HALF OF THE CONUS...SMALL DEVIATIONS TO THE TRACK AND
OVERALL EVOLUTION OF THIS SYSTEM CAN AND WILL RESULT IN LARGE
CHANGES TO THE SENSIBLE WEATHER FELT ACROSS THE CWA. DEFINITELY
SOMETHING TO KEEP AN EYE ON AS WE HEAD INTO THE HOLIDAY TRAVEL
TIME FRAME.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1232 AM EST THU DEC 18 2014

...FINALLY GONNA GET TO VFR...

DEEP DRY AIR AND SUBSIDENCE HAS SQUASHED ALL SNOW OUTSIDE OF THE
LAKE EFFECT...WHICH IS ONLY GOING TO BE ABLE TO PRODUCE VERY LIGHT
SNOW SHOWERS WITH PREVAILING VFR VSBYS. SKIES ALL AREAS ARE MVFR
STILL THOUGH...BUT WILL LIFT TO VFR THIS BY DAYBREAK AT PLN...AND
THIS MORNING AT THE REMAINDER OF THE AIRPORTS. TOTAL CLEARING
EXPECTED HEADING THROUGH THE AFTERNOON AND EVENING HOURS FROM
NORTH TO SOUTH. NORTHERLY WINDS THROUGH THE TAF PERIOD AND
WEAKENING. SOME GUSTS TO 16KTS OR SO FOR ANOTHER FEW HOURS.


&&

.MARINE...
ISSUED AT 212 AM EST THU DEC 18 2014

BASED ON AREA OBSERVATIONS...ALL ADVISORY LEVEL GUSTS HAVE
ENDED...AND AS NORTHERLY WINDS WEAKEN THROUGH THE DAY WITH INCOMING
SFC HIGH PRESSURE...THERE WILL BE NO MARINE ISSUES. WINDS REMAIN
WELL BELOW ADVISORY LEVELS THROUGH THE WEEKEND...WITH ALSO NO
PRECIPITATION EXPECTED.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

UPDATE...SMD
NEAR TERM...SMD
SHORT TERM...MSB
LONG TERM...GILLEN
AVIATION...SMD
MARINE...SMD



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