482
FXUS63 KAPX 101748
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1248 PM EST SUN DEC 10 2023
UPDATE
ISSUED AT 1230 PM EST SUN DEC 10 2023
NORTHWEST FLOW LAKE EFFECT SNOW HAS GOTTEN GOING IN THE WAKE OF
THE COLD FRONT THAT CAME THROUGH THE AREA EARLIER TODAY. THE
MOST PERSISTENT BANDS IMPACTING THE FORECAST AREA ARE PRIMARILY
IMPACTING ANTRIM AND KALKASKA COUNTIES (WITH A LAKE SUPERIOR
CONNECTION EVIDENT, AND ANOTHER IN EXTREME EASTERN LAKE SUPERIOR
CUTTING ACROSS CENTRAL CHIPPEWA COUNTY SOUTH OF THE SAULT. THE
SETUP IS STILL NOT IDEAL WITH INVERSION HEIGHTS NOT MUCH HIGHER
THAN 4K FEET AND INVERSION TOP TEMPERATURES NOT MUCH COOLER THAN
-10C TO -11C. STILL, LAKE-INVERSION TO DELTA TS ARE ABOUT 15C OR
A LITTLE GREATER. ALSO, A LITTLE SYNOPTIC FORCING
BOOST/MOISTURE ENHANCEMENT IS EXPECT OVER THE NEXT SEVERAL
HOURS AS AN IMPULSE WITHIN THE MEAN UPPER-LEVEL TROF OVERHEAD
SLIDES ACROSS THE AREA. THE ONGOING FORECAST STILL LOOKS
REASONABLE AND HAVE ONLY MADE MINOR TWEAKS TO THE NEAR TERM AT
THIS TIME.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
HIGH IMPACT WEATHER POTENTIAL: ACCUMULATING LAKE EFFECT SNOW TODAY-
TONIGHT.
PATTERN SYNOPSIS:
A SHORTWAVE TROUGH/VORTICITY MAX EVIDENT ON SATELLITE IMAGERY WILL
CONTINUE TO PIVOT OVER THE GREAT LAKES THIS MORNING AS A SECONDARY
COLD FRONT SWINGS ACROSS NORTHERN MICHIGAN. A SECOND WAVE LOOKS TO
PROGRESS OVER THE GREAT LAKES LATER THIS AFTERNOON AND EVENING AS
MUCH BROADER LONGWAVE TROUGHING ENCOMPASSES MOST OF THE CONUS EAST
OF THE ROCKY MOUNTAINS.
FORECAST DETAILS:
THE PRIMARY CONCERN TODAY AND TONIGHT WILL BE ACCUMULATING LAKE
EFFECT SNOW ACROSS PORTIONS OF NORTHWEST LOWER AND EASTERN UPPER
MICHIGAN. WHILE LIGHT RAIN/SNOW SHOWERS ARE ONGOING ACROSS PARTS OF
THE CWA, BETTER SHOWER CHANCES WILL ARRIVE LATER THIS MORNING AFTER
THE PREVIOUSLY MENTIONED FRONT WORKS ACROSS THE AREA. NORTHWEST LOW-
LEVEL FLOW BEHIND THE FRONT WILL BRING LAKE EFFECT CHANCES TO THE
TYPICAL SNOWBELT AREAS OF NORTHWEST LOWER AND EASTERN UPPER.
FORECAST SOUNDINGS DISPLAY SATURATED PROFILES THROUGH THE LOWEST 2KM
WITH DELTA-TS AROUND 15C TODAY. SOMEWHAT MEAGER LAPSE RATES LOOK TO
STEEPEN INTO THIS EVENING/TONIGHT WITH CONTINUED COOLING OF THE
PROFILE ABOVE THE SURFACE. A MORE CELLULAR MODE OF LAKE EFFECT
PRECIP IS ANTICIPATED DURING DAYLIGHT HOURS AS THE AFOREMENTIONED
WAVE WORKS OVER THE GREAT LAKES WITH MORE DOMINANT BANDING EXPECTED
TO SET UP HEADING INTO TONIGHT. THIS SHOULD LEAD TO MORE LOCALIZED
HIGHER SNOWFALL AMOUNTS ACROSS PARTS OF THE AREA OVERNIGHT INTO
MONDAY MORNING -- WITH THE MOST LIKELY AREA BEING ANTRIM AND
KALKASKA COUNTIES. MANY PARTS OF NORTHWEST LOWER AND EASTERN UPPER
ARE EXPECTED TO SEE TOTALS AROUND 1" OR LESS BY MONDAY MORNING WITH
HIGHER TOTALS AROUND 2-3" ACROSS AREAS WHERE MORE CONCENTRATED BANDS
SET UP. LOCALIZED TOTALS IN ANTRIM AND KALKASKA COUNTIES OF 4-8"
WILL BE POSSIBLE BY THE END OF THE PERIOD. OTHERWISE, MUCH COOLER
TEMPERATURES ARE IN STORE FOR TODAY. CURRENT TEMPERATURES IN THE MID
TO UPPER 30S WILL GRADUALLY DROP DURING THE DAY BEHIND THE
AFOREMENTIONED COLD FRONT. OVERNIGHT LOWS IN THE 20S ARE IN STORE
FOR THE AREA.
SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/
HIGH IMPACT WEATHER POTENTIAL: MODERATE...WATCHING POTENTIAL FOR
ACCUMULATING LAKE EFFECT SNOW AND GUSTY WINDS MONDAY NIGHT-TUESDAY
PATTERN SYNOPSIS/FORECAST:
LONGWAVE TROUGH AXIS TIGHTENING UP OVER THE CENTER OF THE
COUNTRY...AS RIDGING SLIPS INTO THE WESTERN US, ALONG WITH 1038MB
SURFACE HIGH CENTERED OVER THE ROCKIES. STRONG 120+KT UPPER LEVEL
JET SNAKES FROM THE PAC NW DOWN INTO THE BASE OF THE TROUGH IN THE
SOUTHERN PLAINS, AND THEN UP INTO THE GREAT LAKES...DRIVING A COUPLE
OF TIGHT VORT MAXES IN THE NORTHEAST PORTION OF THE TROUGH. INITIAL
VORT MAX THAT INTENSIFIED A SURFACE LOW OVER N. MI AND DRAGGED THOSE
STRONG WINDS THROUGH THE REGION SATURDAY AFTERNOON LOCATED OVER S.
ONTARIO AS OF 3Z; SECONDARY VORT MAX SPINNING INTO THE REGION IN ITS
WAKE ALONG WHAT LOOKS LIKE A TROWAL AXIS, ACCOMPANIED BY SOME LIGHT
PRECIP. COLD FRONT STRETCHES FROM THE INITIAL SURFACE LOW OVER
ONTARIO DOWN INTO SOUTHERN TX, WITH SOME SEVERE CONVECTION AHEAD OF
IT AMID BETTER MOISTURE AND WARMER TEMPS. SECONDARY COLD FRONT IS
BEHIND THIS, STRETCHING FROM HUDSON BAY DOWN INTO THE DAKOTAS.
SECONDARY TROUGH EXPECTED TO SLIP THROUGH TODAY, AIDED BY SOME
ADDITIONAL ENERGY IN THE BACK OF THE TROUGH OVER WI. THE OVERALL
TROUGH AXIS SHOULD BE DEPARTING THE REGION BY MONDAY...LIFTING
NORTHEASTWARD AND DEVELOPING A POTENT EAST COAST STORM OVER NEW
ENGLAND. MEANWHILE...WE SHOULD SEE SOME IMPROVEMENTS HERE IN
NORTHERN MICHIGAN...AS SHORTWAVE RIDGING BRIEFLY TOUCHES THE REGION
AHEAD OF ANOTHER POTENT NORTHERN STREAM SHORTWAVE TROUGH DIVING OUT
OF CENTRAL CANADA. THIS FEATURE WILL STRENGTHEN THE PRESSURE
GRADIENT OVER US MONDAY NIGHT INTO TUESDAY AS IT SLAMS A LARGELY
ZONAL COLD FRONT INTO THE REGION...LEADING TO ANOTHER ROUND OF
STRONG WINDS...AS WELL AS POTENTIAL FOR ADDITIONAL LAKE EFFECT,
ESPECIALLY ACROSS THE EUP. CURRENTLY EXPECTING THIS BOUNDARY TO HANG
UP OVER THE REGION FOR A TIME...AS RIDGING BEGINS TO BUILD TO OUR
WEST AGAIN IN RESPONSE TO TROUGHING OVER THE WESTERN US AND CANADA.
PRIMARY FORECAST CONCERNS: WINDS MONDAY NIGHT/TUESDAY...
ACCUMULATING LAKE EFFECT SNOW FOR THE EUP TUESDAY...
TO BE HONEST, SETUP FOR MONDAY NIGHT AND TUESDAY, AT LEAST AS FAR AS
WINDS ARE CONCERNED, IS NOT ALL THAT DISSIMILAR TO TODAY...WITH A
STRONG PV MAXIMA PUNCHING INTO THE REGION WITH A DRY SLOT BENEATH A
DECENT JET ALOFT (APPEARING SOMEWHAT WEAKER THAN TODAY'S GIVEN
PROXIMITY TO THE BASE OF ITS ATTENDANT TROUGH AND GREATER
AGEOSTROPHIC FLOW). TIGHTENING PRESSURE GRADIENT LEADING TO
STRENGTHENING SWLY BACKGROUND SURFACE FLOW THROUGH THE NIGHT...WITH
SUSTAINED WINDS OF 15-25KTS A REASONABLE IDEA, PARTICULARLY WHERE
MESOSCALE INFLUENCES SUCH AS CHANNELING COULD ENHANCE WINDS (SUCH AS
BETWEEN NW LOWER AND BEAVER ISLAND, AND/OR PERHAPS THE STRAITS, FOR
A WSW/SW WIND). FOR NOW...THINK THE 6Z-15Z TIMEFRAME WILL BE THE
WINDIEST PORTION OF THE PERIOD...WITH THE DRY SLOT/COLD FRONT MOVING
IN ALONG WITH THE STRONGEST FLOW ALOFT. 30-40KT GUSTS ARE FAIRLY
ACHIEVABLE, NOTING EVEN 925MB FLOW SHOULD RUN AROUND THAT MAGNITUDE.
CAN'T HELP BUT NOTICE THAT 40+KT POTENTIAL IS NOT OUT OF THE
QUESTION, EITHER...WITH SOME SIGNALS OF THIS SHOWING UP AT 850MB,
AND EVEN STRONGER WINDS AT 700MB (GREATER THAN 50KTS). TAPPING INTO
THAT 700MB JET ATTM DOESN'T SEEM AS VIABLE AN IDEA...BUT WILL HAVE
TO KEEP AN EYE OUT IN CASE SIGNALS STRENGTHEN WINDS BELOW THAT IN
THE COMING RUNS. GUSTINESS INTO THE 30-40KT RANGE HAS POTENTIAL TO
LAST LONGER INTO THE AFTERNOON ACROSS THE EUP TUESDAY...WHERE HIGHER
INVERSION HEIGHTS (PERHAPS AROUND 6KFT OR SO) WILL ALREADY BE
SUPPORTIVE OF DEEPER LAKE-INDUCED CONVECTION...FURTHER COMPLICATING
POTENTIAL IMPACTS ACROSS THE EUP.
DO HAVE TO WONDER IF THERE WILL BE A DECENT BURST OF SNOW ALONG THE
FRONT TUESDAY MORNING...NOTING SIGNALS FOR FGEN TO ENHANCE LIFT
ALONG THE FRONT...THOUGH MOISTURE MAY NOT BE QUITE DEEP ENOUGH, SAVE
FOR PERHAPS ACROSS THE EUP, WHERE MOISTURE DOES APPEAR A LITTLE
DEEPER. SIGNALS FOR SW FLOW LAKE ENHANCEMENT WITH THE FRONT ARE
WEAK, PARTICULARLY IF WE END UP A LITTLE DRIER IN THE BOUNDARY
LAYER. THE EUP WILL ALSO BE THE PRIMARY FOCUS FOR LES AS FLOW
BECOMES MORE W/WNW BEHIND THE FRONT IN THE COLDER AIR, AND CLOSER TO
THE VORT MAXIMA WITH THIS LITTLE SYSTEM. WILL HAVE TO SEE WHERE THE
BOUNDARY ENDS UP STALLING OUT TUESDAY...AS THIS COULD HAVE SOME
IMPACT ON WIND DIRECTION AND SUBSEQUENT POSITION OF LES BANDS. WNW
FLOW DOES HAVE BETTER FETCH FOR WHITEFISH POINT. THEREFORE, WOULD
NOT BE SURPRISED IF LOCALIZED AREAS GOT INTO ADVISORY-LEVEL SNOWFALL
TOTALS, AS THE FLOW IS A LITTLE BETTER FOR A SINGLE-BAND TYPE SETUP
FOR THEM. JUST HOW MUCH OF A NW CANT THE FLOW ENDS UP HAVING WILL
INFLUENCE HOW FAR SOUTH ACROSS THE EUP THE BANDING WILL GET...AND
WILL BE WATCHING THIS GOING FORWARD...PARTICULARLY IF THE BAND ENDS
UP NOT MOVING AS MUCH AND THE LES FIREHOSE STAYS IN THE SAME SPOT.
COMBINED WITH THE POTENTIAL FOR GUSTY WINDS...THINK WE WILL HAVE TO
KEEP AN EYE ON AT LEAST CHIPPEWA COUNTY TUESDAY.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
HIGH IMPACT WEATHER POTENTIAL: LOW FOR NOW...WATCHING BREEZY
CONDITIONS WEDNESDAY INTO THURSDAY...
PATTERN SYNOPSIS/FORECAST:
TROUGHING GETS CUT OFF OVER THE WESTERN US FOR MIDWEEK, AND BECOMES
A MAJOR FACTOR IN THE REMAINDER OF THE EXTENDED. FOR ONE, IT SHOULD
BEGIN TO BUILD RIDGING AND ATTENDANT SURFACE HIGH OVER THE OH
VALLEY, AS WARM ADVECTION SPREADS ACROSS CENTRAL CANADA. SOME
POTENTIAL FOR THE UPPER GREAT LAKES TO REMAIN UNDER THE INFLUENCE OF
HIGH PRESSURE AND MILDER WEATHER...THOUGH AS WE SHOULD BE ON THE
NORTHERN EDGE OF THIS...HAVE SOME CONCERNS WE MAY REMAIN A LITTLE
BREEZY INTO THE LATTER HALF OF THE WEEK, AS ANOTHER NORTHERN STREAM
SYSTEM BEGINS TO TREK ACROSS CENTRAL CANADA. WILL HAVE TO SEE HOW
FAR SOUTH THIS SYSTEM'S INFLUENCE ENDS UP, AS IT COULD LINGER A BCZ
OVER THE REGION, AND PLAY A ROLE IN INTERACTION WITH THAT UPSTREAM
CUT OFF LOW AS IT EJECTS INTO THE PLAINS. BOTTOM LINE...CURRENTLY
LOOKING AT A BREEZY BUT PERHAPS MILDER MID/LATE WEEK...WITH
INCREASING POTENTIAL (DESPITE LINGERING UNCERTAINTY) FOR MORE
UNSETTLED WEATHER LATE IN THE WEEK INTO NEXT WEEKEND.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
LOW CLOUDS, ENHANCED BY OVER-LAKE INSTABILITY, WILL PROVIDE
MAINLY MVFR CIGS ACROSS THE AREA THROUGH THE 18Z TAF VALID TIME.
MOST OF THE LAKE EFFECT SNOW IN THIS SETUP IS EXPECTED TO MISS
THE TERMINALS, WITH KCIU BEING THE MOST NOTABLE EXCEPTION. GUSTY
NORTHWEST WINDS WILL GRADUALLY TAPER OFF TONIGHT, WITH A SHIFT
TO WESTERLY LATE IN THE PERIOD.
MARINE
SMALL CRAFT WINDS AND WAVES WILL CONTINUE ACROSS NORTHERN GREAT
LAKES NEARSHORE WATERS TODAY BEFORE DIMINISHING THIS EVENING.
ADVISORY CONDITIONS ARE EXPECTED TO LINGER ACROSS SOME LAKE HURON
NEARSHORE ZONES INTO TONIGHT. LOOKING AHEAD, SMALL CRAFT WINDS AND
WAVES ARE EXPECTED AGAIN MONDAY NIGHT INTO TUESDAY -- ALONG WITH THE
POTENTIAL FOR GALES OVER SOME NEARSHORE WATERS DURING THAT
TIME FRAME.
APX WATCHES/WARNINGS/ADVISORIES
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ021-027.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LHZ345-
346.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LHZ347>349.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ323-
341-342-344>346.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LSZ321-
322.
UPDATE...PBB
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...PBB
MARINE...
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