Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 012339
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
639 PM EST SUN FEB 1 2015

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 349 PM EST SUN FEB 1 2015

...ACCUMULATING SNOW FAR SOUTH TONIGHT/BITTERLY COLD OVERNIGHT...

HIGH IMPACT WEATHER POTENTIAL: ACCUMULATING SNOW ALONG/SOUTH OF A
CADILLAC-OSCODA LINE TONIGHT WITH SOME BLOWING SNOW.  BITTERLY COLD
WIND CHILLS OVERNIGHT AS TEMPERATURE PLUMMET.

PATTERN SYNOPSIS/FORECAST: 17Z SURFACE ANALYSIS SHOWS LOW PRESSURE
JUST MOVING PAST STL AND TOWARD A LARGE AREA OF 3-4MB/3H PRESSURE
FALLS OVER INDIANA/OHIO.  SUB-ZERO COLD CONTINUES TO WRAP AROUND THE
"WARM BUBBLE" THAT IS LAKE SUPERIOR...WITH TEMPERATURES IN THE
SINGLE DIGITS ABOVE AND BELOW ZERO ACROSS EASTERN UPPER AT EARLY
AFTERNOON. WELL-DEFINED SHORT WAVE TROUGH/VORTICITY CENTER ROLLING
ALONG THE IOWA/MISSOURI BORDER...SPREADING SNOW WELL TO ITS NORTH
AND EAST.  NORTHERN EDGE OF SNOW SHIELD HAS HELD PRETTY FIRM ALONG
THE M-55 CORRIDOR...LOCAL RADAR RETURNS STARTING TO "HALF-CIRCLE"
THE RADAR INDICATIVE OF SUB-CLOUD SUBLIMATION GOING ON BETWEEN M-32
AND M-72.  HEAVIEST SNOW STILL OCCURRING ALONG/SOUTH OF THE I-96
CORRIDOR.  SOME SHALLOW SNOW SHOWERS COMING IN OFF LAKE HURON IN
NORTHEAST BOUNDARY LAYER FLOW FROM SLH SOUTHWARD.

SURFACE LOW WILL TRACK ACROSS INDIANA AND OHIO TONIGHT...WHILE SHORT
WAVE TROUGH/VORTICITY CENTER SHOULD ALSO TRACK EAST-NORTHEAST ALONG
THE SOUTHERN MICHIGAN BORDER AND INTO THE LOWER LAKES BY MONDAY.

PRIMARY FORECAST CONCERNS: NORTHWARD EXTENT OF SNOW SHIELD...
COMBINED WITH LIGHT LAKE EFFECT OFF LAKE HURON INTO NORTHEAST
LOWER...AND SNOW ACCUMULATIONS WITH BOTH.  LOW TEMPERATURES
OVERNIGHT (POTENTIALLY PRETTY COLD ESPECIALLY THE FARTHER NORTH ONE
GOES).

TONIGHT: FIRST ISSUE IS SYNOPTIC SNOWFALL...AND WITH VORTICITY
CENTER TRACKING TOWARD SOUTHERN LOWER MICHIGAN THERE APPEARS TO BE A
PERIOD OF DECENT FORCING FOR ASCENT (POTENTIAL VORTICITY ADVECTION/
QG SUPPORT) OVER ABOUT THE SOUTHEAST THIRD OF THE FORECAST AREA THIS
EVENING INTO THE EARLY OVERNIGHT HOURS.  SYSTEM WILL BE FIGHTING DRY
AIR ADVECTION FROM THE NORTHEAST IN THE LOW LAYERS...BUT HAVE SOME
CONCERNS FOR AREAS ADJACENT TO SAGINAW BAY (AND FURTHEST AWAY FROM
DRY AIR "GRADIENT").  NORTHEAST FLOW OFF LAKE HURON...WHILE
INSTABILITY IS SHALLOW...CERTAINLY WON`T HURT THE CAUSE.  SO
THINKING IS THAT AN INCREASE IN SNOWFALL INTENSITY WILL SPREAD INTO
AREAS ALONG-SOUTH OF ROUGHLY A CAD-OSC LINE EARLY THIS EVENING...
WITH A STRIPE OF 2-4 INCHES OF SNOW FALLING MOSTLY THIS EVENING IN
THIS CORRIDOR.  GUSTY WINDS WILL ALSO RESULT IN BLOWING/DRIFTING
SNOW AS WELL...SO LIKE THE IDEA OF PUTTING UP A WINTER WEATHER
ADVISORY FOR AT LEAST GLADWIN/ARENAC/IOSCO COUNTIES...ON THE FENCE
ABOUT ROSCOMMON/OGEMAW/MISSAUKEE COUNTIES AS HAVE NO GOOD IDEA AS TO
WHERE THE EXACT SNOWFALL GRADIENT WILL SET UP...BUT MAY THROW THEM
IN THERE FOR GOOD MEASURE.

REMAINDER OF THE AREA WILL BE CLOUDY BUT DRY TO START...WITH CLOUDS
DECREASING FROM THE NORTH AND NORTHWEST OVERNIGHT AS SYNOPTIC SYSTEM
DEPARTS.  THIS LEADS TO THE NEXT ISSUE OF LOW TEMPERATURES...AND
ALREADY OFF TO A COLD START WITH CLEARING SKIES OVERNIGHT AND WINDS
MOST LIKELY TO DE-COUPLE.  EXPECT 10 BELOW TO 20 BELOW ZERO READINGS
ACROSS EASTERN UPPER/STRAITS REGION...AND ZERO TO AROUND 10 BELOW
ACROSS INTERIOR NORTHERN LOWER (WITH SOME COLDER SPOTS LIKELY).
WIND CHILLS LIKELY AT OR BELOW 20 BELOW ZERO MONDAY MORNING...SO MAY
BE PUSHING WIND CHILL ADVISORY CRITERIA THOUGH WILL DEPEND ON
MEETING WIND SPEED CRITERIA (10 MPH...WHICH MAY BE A STRETCH ACROSS
MUCH OF EASTERN UPPER).  WILL BE COLD REGARDLESS...SO BE ADVISED.

&&

.SHORT TERM...(MONDAY THROUGH WEDNESDAY)
ISSUED AT 349 PM EST SUN FEB 1 2015

HIGH IMPACT WEATHER POTENTIAL: MINIMAL

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: WHILE NO DOUBT DOWNRIGHT
DULL FROM A SNOW FANS PERSPECTIVE...SIMPLE PERSISTENCE OF PATTERN AN
IMPRESSIVE ONE INDEED. SURE DON`T LOOK FOR IT TO CHANGE ANYTIME
SOON...WITH BACKGROUND LONG WAVE PATTERN OF WESTERN
RIDGING/NORTHEAST NAMERICA TROUGHING REMAINING FOR THE FORESEEABLE
FUTURE. THIS...OF COURSE...PLACES NORTHERN MICHIGAN IN THE CROSS
HAIRS OF DRY NORTHWEST FLOW AND AN ACTIVE CLIPPER WAVE TRAIN FOCUSED
JUST SOUTH OF OUR AREA. WHILE PERIODS OF LIGHT SNOW WILL OCCUR THE
NEXT SEVERAL DAYS...JUST NOT SEEING EVIDENCE OF ANY APPRECIABLE
ACCUMULATIONS.

PRIMARY FORECAST CHALLENGES/CONCERNS: TEMPERATURE/CLOUD TRENDS AND
ADDRESSING LIGHT SNOW POTENTIAL.

DETAILS: CURRENT SOUTHERN LAKES SNOW STORM EXPECTED TO PUSH INTO THE
ATLANTIC MONDAY...WITH ELONGATED HIGH PRESSURE QUICKLY FOLLOWING IN
ITS WAKE. OVERHEAD LOW LEVEL FLOW BACKS STEADILY IN THE
PROCESS...WITH NORTHERLY FLOW EARLY MONDAY BECOMING SOUTHWEST BY
MONDAY EVENING. TEMPERATURES MORE THAN COLD ENOUGH TO SUPPORT A LAKE
RESPONSE...ALTHOUGH COMPLETE LACK OF ANY SYNOPTIC MOISTURE
CONTRIBUTION AND PALTRY INVERSION HEIGHTS (SUB H8) SURE SAY
OTHERWISE. LAKE INDUCED SHALLOW TOPPED STRATOCU LOOKS TO RESIDE IN
THE DGZ...AT LEAST ARGUING FOR SOME VERY LIGHT SNOW SHOWERS/FLURRIES
AT TIMES. AND...THAT SAME STORY GOES RIGHT THROUGH MONDAY
NIGHT...ALTHOUGH APPROACH OF SUBTLE WAVE/ATTENDANT SURFACE TROUGH
DOES BRING SOME LATE NIGHT DOWN LOW MOISTURE CONTRIBUTION AND AN
EVER SO SLIGHT UPTICK IN INVERSION HEIGHTS. MAIN BENEFICIARY OF THE
ABOVE LOOKS TO BE THE SNOW BELTS NORTH OF THE SOO AS WINDS REMAIN
WEST/SOUTHWEST. SIMPLY REMAINING MARGINAL AT BEST ACROSS NORTHERN
LAKE MICHIGAN...ALTHOUGH WOULD EXPECT SNOW SHOWER COVERAGE TO
INCREASE SOME IN MACKINAC COUNTY DOWN THROUGH THE TIP OF THE MITT AS
LOW LEVEL FLOW BECOMES ENERGIZED.

GUIDANCE CONTINUES TO SIDE WITH WHAT IS NOW A SEVERAL WEEK TREND OF
SENDING NEXT SYSTEM OF INTEREST OFF TO OUR SOUTH...WITH ITS MAIN
IMPACTS TARGETING SOUTHERN LOWER MICHIGAN LATER TUESDAY INTO TUESDAY
NIGHT. SURFACE RESPONSE WEAK AT BEST...SUGGESTING LAKE AGGREGATE
INFLUENCES TO LOW LEVEL WINDS FIELDS OVER THE NORTHERN LAKES. SYSTEM
ITSELF MAY BE ABLE TO SQUEEZE OUT A LITTLE SNOW...WITH LAKE
PROCESSES BECOMING MORE OF A FACTOR HEADING THROUGH LATER TUESDAY
INTO WEDNESDAY. DESPITE INCREASING MOISTURE...SIMPLE LACK OF ANY
REAL SIGNIFICANT SYNOPTIC CONTRIBUTION EXPECTED TO KEEP LAKE
PROCESSES MUTED...KEEPING OVERALL SNOW INTENSITY ON THE LIGHT SIDE.
BEST CHANCE TO SEE ANY MEANINGFUL ACCUMULATIONS WILL BE ACROSS THE
LAKE SUPERIOR SNOW BELTS GIVEN DEEPER MOISTURE AND STILL PLENTIFUL
OPEN WATER. EVEN HERE...LOSS OF IN-CLOUD DGZ WHEN BETTER LAKE
PROCESSES ARRIVE SHOULD KEEP SNOW TOTALS WELL IN CHECK.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 349 PM EST SUN FEB 1 2015

WILL START OFF MIDWEEK WITH A SHOT OF COLD AIR ON THE HEELS OF A
DEPARTING CLIPPER. THIS OF COURSE MEANS CHANCES FOR SOME LAKE EFFECT
SNOWS IN NORTHWEST FLOW FAVORED AREAS...PRIMARILY EARLY IN THE DAY
AS WINDS WILL BACK TO THE SOUTHWEST AS HIGH PRESSURE BUILDS TO OUR
SOUTH THROUGHOUT THURSDAY. THERE COULD BE SOME SYSTEM SNOW OVER THE
WEEKEND...BUT GIVEN THE CURRENT FAVORED STORM TRACK GOING SOUTH OF
US WILL KEEP CHANCE POPS AND SEE HOW THINGS DEVELOP AS WE GET A BIT
CLOSER. TEMPERATURES WILL REMAIN AT OR BELOW NORMAL THROUGH THE
WEEKEND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 639 PM EST SUN FEB 1 2015

THE NRN EDGE OF WIDESPREAD SYNOPTIC SNOW WILL CONTINUE TO IMPACT
LOCATIONS ALONG AND SOUTH OF A LINE FROM APN TO TVC TONIGHT AS A
POTENT AREA OF LOW PRESSURE TRACKS EASTWARD THRU THE OHIO VALLEY.
CONDITIONS WILL REMAIN MVFR TO OCCASIONALLY IFR WITHIN THIS AREA.
LOCATIONS NORTH OF THIS LINE WILL REMAIN UNDER MVFR CIGS THIS
EVENING...WITH LOW CLOUDS DIMINISHING OVERNIGHT. ALL TAF SITES
SHOULD RETURN TO VFR CONDITIONS FOR MONDAY AS HIGH PRESSURE BUILDS
INTO THE REGION. NE WINDS OF 10 TO 20 KTS WITH SOME HIGHER GUSTS
WILL SHIFT TO THE NORTH OVERNIGHT AND THEN TO THE NW ON MONDAY.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 5 AM EST MONDAY FOR MIZ033>036-041-
     042.

LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

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


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