121
FXUS63 KDTX 162301
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
601 PM EST MON DEC 16 2024
KEY MESSAGES
- TEMPERATURES TREND DOWN THROUGH THE WEEK WITH HIGHS DOWN TO AROUND
FREEZING FOR THURSDAY AND FRIDAY.
- THERE IS A CHANCE OF LIGHT SNOW, POSSIBLY MIXING WITH RAIN, LATE
TUESDAY NIGHT INTO WEDNESDAY MORNING. MINIMAL ACCUMULATION EXPECTED
WITH AROUND A HALF INCH OR LESS FOR MOST LOCATIONS DUE TO WARMING
TEMPERATURES THROUGH THE MORNING.
- A BETTER ORGANIZED SYSTEM WILL THEN MOVE THROUGH THURSDAY EVENING
INTO FRIDAY BRINGING A BETTER CHANCE FOR ACCUMULATING SNOW.
AVIATION
A COLD FRONT WILL PROGRESS WEST TO EAST THROUGH THE AREA THIS
EVENING. THIS WILL BEGIN THE PROCESS OF SCOURING OUT THE LOWEST
STRATUS AND FOG/DRIZZLE INTO THE OVERNIGHT HOURS, BUT WITH MVFR AND
PERIODS OF IFR CIGS PERSISTING. MAIN CLEARING WILL HOLD OFF UNTIL
LATER IN THE FORECAST AS CIGS TREND FROM MVFR TO LOWER VFR IN THE
AFTERNOON/EVENING TUESDAY. SOUTHWEST WINDS WILL PICK UP WITH THE
FROPA WITH GUSTS TO 25 KNOTS POSSIBLE INTO THE OVERNIGHT.
FOR DTW...BORDERLINE IFR/LIFR WILL PERSIST IN COMBINATIONS OF CIG
AND VSBY UNTIL THE COLD FRONT MOVES THROUGH AROUND 02Z. SOUTHWEST TO
WEST WIND PICKING UP TO 25 KNOT GUSTS AFTER THE FRONT HELPS LIFT
CEILING INTO MVFR OVERNIGHT.
DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING AT OR BELOW 5000 FEET TONIGHT AND TUESDAY.
* LOW FOR CIGS/VSBY AT 200 FT AND/OR 1/2SM EARLY THIS EVENING.
PREV DISCUSSION
ISSUED AT 336 PM EST MON DEC 16 2024
DISCUSSION...
THE STEADIER RAIN SHOWERS ARE PUSHING OFF TO THE EAST BUT THE
MOISTURE REMAINS OVER SE MI WITH A SHALLOW BUT SATURATED LAYER BELOW
800 MB AS THE COLD FRONT WILL NOT SWEEP THROUGH TIL THIS EVENING.
THIS WILL KEEP SOME POCKETS OF LIGHT RAIN SHOWERS AND/OR DRIZZLE
GOING INTO THE EVENING HOURS. TEMPERATURES TONIGHT ARE EXPECTED TO
STAY ABOVE FREEZING SO THERE IS NOT ALOT OF CONCERN FOR WATER ON
ROADS TO FREEZE TONIGHT. HELPING TO KEEP TEMPERATURES UP WILL BE AN
ENHANCED WIND FIELD AS POST FRONTAL LOW LEVEL LAPSE RATES INCREASE
WITH SLIGHT COOL ADVECTION. THOUGH THE MIXING LAYER IS ONLY GOING TO
GET TO 2-3KFT, SHOULD TAP INTO A POCKET OF WINDS AROUND 30 KNOTS SO
WE COULD GET GUSTS IN THE 20-30 MPH RANGE TONIGHT.
QUIETER WEATHER ON TUESDAY AS HIGH PRESSURE AT THE SURFACE SLIDES
THROUGH THE OHIO VALLEY AND LOW AMPLITUDE SHORTWAVE RIDGE STARTS
WORKING INTO THE REGION OFFERING INCREASING HEIGHTS AND DRIER AIR
ALOFT. THE LOWERING SUBSIDENCE INVERSION WILL KEEP OVERCAST SKIES
THOUGH AS LOW LEVELS REMAIN FAIRLY SATURATED. COOLER ON TUESDAY AS
WELL AS THE THERMAL RIDGE GETS PUSHED OUT OF THE AREA WITH THE FRONT
THIS EVENING AND 850MB TEMPS SETTLE MORE AROUND 0C. HIGHS EXPECTED
TO BE JUST A FEW DEGREES ABOVE NORMAL AROUND 40F.
THERE ARE A COUPLE OPPORTUNITIES FOR PRECIPITATION THIS WEEK AS THE
ACTIVE JET CONTINUES TO WAVER OVER THE REGION. FIRST CHANCE WILL
COME LATE TUESDAY NIGHT INTO WEDNESDAY MORNING AS A COLD FRONT ON
THE LEADING EDGE OF A POSITIVELY TILTED TROUGH WORKS ACROSS THE
AREA. SYSTEM IS A BIT DISJOINTED AS THE BEST VORTICITY WILL BE
DIVING THROUGH OHIO BUT WILL SHEAR TO THE NE UP ACROSS SE MI. THERE
IS SOME WEAK FGEN NOTED THAT WILL WORK ACROSS A PORTION OF THE
FORECAST AREA MAINLY BETWEEN 09-15Z. TEMPERATURE WILL NOT BE
FAVORABLE FOR A PURE SNOW EVENT AS OVERNIGHT LOWS ARE AROUND 30 WITH
WARM AIR GETTING PULLED NORTH AHEAD OF THE INITIAL FRONT. COLDER AIR
WILL BE HELD BACK TO THE WEST TIED TO THE NEXT WAVE DIGGING INTO THE
MIDWEST ON THE HEALS OF THIS LEAD WAVE. SEEMS TO BE ENOUGH
SEPARATION BETWEEN THEM TO NOT ENHANCE ANY MESOSCALE FEATURES OR
INCREASE FORCING. MOISTURE IS NOT OVERLY ABUNDANT EITHER AS THE
SYSTEM TO THE SOUTH CUTS OFF MUCH OF IT. CURRENT MODEL SOUNDINGS
HAVE DECENT SATURATION FOR A FEW HOURS BUT MOSTLY IN THE 0 TO -10C
LAYER. THEY ALSO SUGGEST DIFFICULTY IN FULLY SATURATING THROUGH THE
DGZ EVEN FOR A FEW HOURS WITH HINTS OF DRY LAYERS ALOFT AND IN THE
LOWER LAYERS. HAVING SAID ALL THAT, WE ARE LOOKING FOR A SEVERAL
HOUR PERIOD OF WET SNOW BECOMING RAIN/SNOW MIX OR CHANGING TO ALL
RAIN IN THE EARLY MORNING, ESPECIALLY SOUTH OF I94. QPF IS LARGELY
UNDER A TENTH OF AN INCH AND WITH THE MIXED PRECIP LIKELY, SNOWFALL
ACCUMULATIONS AROUND A HALF INCH OR LESS ARE EXPECTED.
THE NEXT WAVE LOOKS TO BE STRONGER AND BETTER ORGANIZED FOR THE END
OF THE WEEK. THE WAVE WILL ENTER THE PACIFIC NW WEDNESDAY AND WILL
THEN TRACK EAST-SOUTHEAST THROUGH THE GREAT LAKES THURSDAY EVENING
THROUGH FRIDAY. COLDER AIRMASS WILL BE IN PLACE THANKS TO THE 2 MID
WEEK COLD FRONTS SO SNOW LOOKS TO BE THE FAVORED PTYPE FOR THIS
SYSTEM. A LEADING BAROCLINIC ZONE DRAPED ACROSS LOWER MI LOOKS TO
HELP THE PRECIP BEGIN THURSDAY EVENING BEFORE THE SURFACE LOW AND
COLD FRONT TRACK THROUGH EARLY FRIDAY MORNING. AT THIS TIME WITH THE
TRACK OF THE LOW PASSING JUST TO OUR SOUTH, OR POSSIBLY THROUGH FAR
SOUTHERN MI, WE'D BE ON THE NORTH SIDE AND IN THE FAVORABLE REGION
FOR ACCUMULATING SNOWFALL. WE THEN LOOK TO REMAIN WITHIN THE TROUGH
THROUGH THE WEEKEND WITH SEASONALLY COOL AIR AND NORTHWESTERLY
FLOW FAVORING SOME LAKE EFFECT SNOW ACROSS THE REGION.
MARINE...
A COLD FRONT OVER LAKE MICHIGAN WILL SWEEP EASTWARD ACROSS LAKE
HURON AND LAKE ERIE THIS EVENING WITH SSE WIND VEERING TO WSW
TONIGHT. DEEPER MIXING WITHIN THE COLD ADVECTION WILL BRING
INCREASING WIND SPEEDS OVERNIGHT TO AROUND 20 TO 25 KNOTS WITH GUSTS
TO AROUND 30 KNOTS THAT LAST THROUGH EARLY TUESDAY BEFORE TAPERING
OFF. A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE LAKE HURON
NEARSHORE WATERS THROUGH TUESDAY AFTERNOON. THE FRONT WILL ALSO ALLOW
ANY REMAINING FOG TO START TO MIX OUT THIS EVENING, AS WELL AS BRING
A REDUCTION IN THE COVERAGE OF SHOWERS. WEAK HIGH PRESSURE SETTLES
ACROSS THE SOUTHERN GREAT LAKES LATE TUESDAY INTO WEDNESDAY,
PROMOTING LIGHTER WINDS AND WAVE HEIGHTS. THE NEXT COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY, BRINGING AN AREA OF MELTING SNOW.
WINDS BEHIND THIS FRONT SHIFT TO NORTHWESTERLY BUT LOOK TO REMAIN
MODERATE, ON THE ORDER OF 20 KNOTS, AS THE COLD ADVECTION WILL BE
RELATIVELY WEAK AND SHORT-LIVED. A RIDGE OF HIGH PRESSURE ON
THURSDAY BRINGS LIGHTER WINDS BEFORE THE NEXT STRONGER CLIPPER LOW
TRACKS IN FROM THE MIDWEST THURSDAY NIGHT INTO FRIDAY.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST TUESDAY FOR LHZ421-422.
SMALL CRAFT ADVISORY UNTIL 4 PM EST TUESDAY FOR LHZ441>443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....DG
DISCUSSION...DRK
MARINE.......TF
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