023
FXUS63 KDTX 170401
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1101 PM EST THU JAN 16 2025
KEY MESSAGES
- WIDESPREAD ACCUMULATING SNOWFALL RETURNS LATE FRIDAY NIGHT THROUGH
SATURDAY MORNING. SNOW ACCUMULATIONS OF 1 TO 2 WITH LOCALIZED 3
INCHES POSSIBLE, ESPECIALLY ACROSS THE HIGHER ELEVATIONS INTO THE
THUMB. LESS THAN AN INCH TOWARDS THE SAGINAW VALLEY. FORECAST
REMAINS SENSITIVE TO LOWER LEVEL TEMPERATURES.
- ARCTIC AIR IS EXPECTED ACROSS SOUTHEAST MICHIGAN SUNDAY THROUGH
WEDNESDAY WITH THE COLDEST AIRMASS OF THE WINTER SEASON THUS FAR.
- OVERNIGHT LOWS WILL DROP BELOW ZERO DEGREES WITH WIND CHILLS
FALLING TO -15 F TO -20 F OR LOWER MONDAY AND TUESDAY MORNING WITH
HIGH TEMPERATURES IN THE SINGLE DIGITS.
AVIATION
AREA OF LOW STRATUS WILL PERSIST INTO THE EARLY MORNING HOURS.
POTENTIAL FOR A TRANSITION FROM VFR TO MVFR DURING THIS TIME, AS
INCREASING SUBSIDENCE AND DRYING OCCURS ABOVE THE INVERSION. THIS
PROCESS WILL EVENTUALLY LEAD TO A CLEARING OF EXISTING STRATUS LATE
TONIGHT AND EARLY FRIDAY, AS LOW LEVEL FLOW BACKS WITH TIME FROM
WEST TO SOUTHWEST AND WARM AIR WORKS BACK INTO THE REGION. THIS
PATTERN POINTS TOWARD A PERIOD OF LITTLE TO NO LOWER STRATUS FOR THE
FRIDAY PERIOD, WITH SIMPLY AN INCREASE IN MID CLOUD AHEAD OF THE
NEXT SYSTEM. SOUTHERLY WINDS TURN GUSTY FRIDAY AFTERNOON DESPITE THE
INCREASE IN OVERALL STABILITY, SUPPORTING SOME GUSTINESS IN EXCESS
OF 25 KNOTS. THESE CONDITIONS HOLD INTO THE EVENING HOURS FRIDAY,
BEFORE PRECIPITATION POTENTIAL INCREASES AGAIN FRIDAY NIGHT.
DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILINGS AOB 5000 FEET TONIGHT. LOW FRIDAY.
* MEDIUM FOR A PRECIPITATION TYPE OF RAIN AND MELTING SNOW AT
ONSET AFTER 06Z FRIDAY NIGHT.
PREV DISCUSSION
ISSUED AT 354 PM EST THU JAN 16 2025
DISCUSSION...
TRAILING WAVE THIS AFTERNOON WITH THE STEEPENED LOW LEVEL LAPSE
RATES HAS KEPT ISOLATED TO SCATTERED SNOW SHOWERS STREAMING IN FROM
LAKE MICHIGAN THROUGH MUCH OF THE AFTERNOON. AS GREATER HEIGHT RISES
ENCROACH INTO THE AREA, LAKE EFFECT SNOW SHOWERS SHOULD LARGELY COME
TO AN END THIS EVENING. CANNOT COMPLETELY RULE OUT A FEW LOCALIZED
FLURRIES INTO TONIGHT, BUT WILL CONTINUE TO LEAVE MENTION OUT GIVEN
THE SPARSE NATURE WITH NO EXPECTED IMPACTS. A FEW BREAKS IN THE
CLOUDS WILL ALSO BE POSSIBLE TONIGHT WITH GREATER MID-LEVEL DRY AIR
INTRUSION ATTEMPTING TO ERODE SOME OF THE LOWER LAKE CLOUDS.
THE MID-UPPER LEVEL RIDGE AXIS MOVES EAST BY TOMORROW AFTERNOON AND
LEADS TO DEEPER SOUTHWEST FLOW. THE INCREASING SOUTH TO SOUTHWEST
GRADIENT AHEAD OF A NORTHERN STREAM TROUGH AND LOW PRESSURE SYSTEM
PASSING OVER NORTHERN LAKE SUPERIOR RESULTS IN A PERIOD OF WARM AIR
ADVECTION. A STRONG SOUTHWESTERLY LOW LEVEL JET WILL PUSH 850 MB
TEMPERATURES SLIGHTLY ABOVE 0C INTO SOUTHEAST MICHIGAN BY TOMORROW
MORNING. THIS WILL BE AROUND 10 TO 12 DEGREES C WARMER THAN TODAY
AND WILL HELP PUSH DAYTIME HIGHS FOR TOMORROW BACK TOWARDS THE
TYPICAL AVERAGE HIGH IN THE LOWER 30S. AREAS ACROSS THE SOUTHERN
HALF OF THE CWA SHOULD BE ABLE TO CLIMB SLIGHTLY ABOVE THE FREEZING
MARK. MIXING DEPTHS ARE NOT FORECAST TO CLIMB TOO HIGH INTO THE
STRONGEST LOW LEVEL WINDS FRIDAY AFTERNOON AND EVENING, BUT IT WILL
STILL BE POSSIBLE FOR GUSTS MOSTLY IN THE 30 TO 40 MPH RANGE WITH
PEAK WINDS OCCURRING FOR A FEW HOURS SURROUNDING SUNSET. THE THUMB
IS THE FAVORED AREA FOR THE HIGHER END OF THIS GUST RANGE.
AN ARCTIC FRONT WILL THEN SLIDE THROUGH MICHIGAN LATE FRIDAY NIGHT
AND SATURDAY MORNING WHILE PHASING OF THE NORTHERN LAKE SUPERIOR
TROUGH AND A SOUTHERN STREAM PV ANOMALY OCCURS OVERHEAD. SOUTHEAST
MICHIGAN WILL BE UNDER AN AREA OF SUFFICIENT SYNOPTIC LIFT BETWEEN
THE RIGHT ENTRANCE REGION OF THE NORTHERN STREAM UPPER JET AND THE
LEFT EXIT REGION OF THE SOUTHERN STREAM UPPER JET. THE FRONT WITH
GREATER LARGER SCALE SUPPORT BRINGS HIGH CONFIDENCE IN WIDESPREAD
PRECIPITATION WITH THE PEAK OF THE EVENT FOCUSED MAINLY BETWEEN 1 AM
FRIDAY TO 9 AM SATURDAY. MANY OF THE MODELS ARE IN GOOD AGREEMENT ON
QPF AMOUNTS OF 0.1" TO 0.2" A SELECT FEW AT THE 0.3" MARK. THE
CHALLENGE WITH THIS FORECAST WILL BE THE LOWER LEVEL TEMPERATURES
AND THE RESULTANT P-TYPE DURING THE OVERNIGHT PERIOD AS COLDEST AIR
LOWER LEVEL TEMPERATURES LAG THE FRONT A LITTLE. SURFACE
TEMPERATURES CURRENTLY FORECAST TO BE RIGHT AROUND FREEZING,
ESPECIALLY TOWARDS THE DETROIT METRO REGION AND SOUTHERN MICHIGAN
BORDER WHERE SURFACE TEMPERATURES MAY BE A 1-2 DEGREES ABOVE
FREEZING. THE DEPTH OF THE SURFACE WARM LAYER DOES NOT APPEAR TO BE
VERY DEEP EVEN ON THE WARMER SOUNDINGS. THIS WOULD FAVOR A
PREDOMINATELY MELTING/WET SNOW IN THESE AREA. COLDER AIR ALONG THE
GLACIAL RIDGE INTO THE THUMB IS WHERE GREATEST CONFIDENCE RESIDES
WITH THE PREDOMINATE SNOW P-TYPE. SNOWFALL TOTALS OF 1 TO 2 INCHES
WITH A LOCALIZED 3 INCHES POSSIBLE. THE UPPER END OF SNOWFALL WILL
REMAIN FOCUSED ALONG THE HIGHER ELEVATIONS OF THE GLACIAL RIDGE INTO
THE EASTERN PORTIONS OF THE THUMB. DETROIT METRO AND SOUTHERN
MICHIGAN BORDER WITH A LEAN TOWARDS THE MORE PREDOMINATE SNOW TYPE
WILL FALL MOSTLY BETWEEN THE 0.5" TO 1.5" OF SNOWFALL. THE TRI-
CITIES WILL BE JUST NORTH OF THE BEST FORCING/QPF AND ARE MORE
LIKELY TO SEE THE LOWER END OF SNOWFALL WHERE ONLY A FEW TENTHS TO A
HALF INCH OF SNOWFALL ARE POSSIBLE. FORECAST SNOWFALL AND P-TYPE
REMAINS SENSITIVE TO THE LOWER LEVEL TEMPERATURE TRENDS.
PERHAPS THE BIGGER STORY OF THIS FORECAST WILL BE THE ARRIVAL OF AN
ARCTIC AIRMASS THIS WEEKEND INTO NEXT WEEK. THE FIRST CONCERN WILL
BE FOR ANY LEFTOVER WET ROADS FROM THE SATURDAY MORNING SNOW TO
QUICKLY FREEZE UP BY SATURDAY EVENING AS TEMPERATURES FALL FROM
AROUND FREEZING TO AROUND 20 DEGREES. THEN THE COLDEST AIR OF THE
SEASON COMES BARRELING INTO THE REGION EARLY SUNDAY MORNING INTO THE
MIDDLE OF THE WEEK AS 850 MB TEMPERATURES PLUMMET TO AROUND -25C.
SINGLE DIGIT LOWS WILL START SUNDAY MORNING WITH HIGHS ONLY CLIMBING
INTO THE TEENS SUNDAY AFTERNOON. MONDAY AND TUESDAY WILL BE THE
COLDEST DAYS OF THIS STRETCH WITH HIGH CONFIDENCE FOR DAYTIME HIGHS
TOPPING OUT IN THE SINGLE DIGITS, MORNING LOWS IN THE NEGATIVE
SINGLE DIGITS, AND WIND CHILLS WELL BELOW ZERO IN THE -15F TO -20F.
THESE TEMPERATURES WOULD EASILY ACHIEVE THE COLD ADVISORY HEADLINE
CRITERIA WITH WIND CHILLS OF -25F NOT OUT OF THE QUESTION. COLD AIR
WOULD ALSO BRING PERSISTENT LAKE EFFECT CLOUDS AND SNOW SHOWERS. THE
DEGREE OF COLD AIR DOESN'T BODE WELL FOR GREAT SNOWFALL
MICROPHYSICS, SO ANY SNOW ACCUMULATION OCCURRING WITHIN THIS REGIME
WOULD LIKELY BE LIMITED ACROSS MUCH OF THE CWA. TEMPERATURES BEGIN
TO REBOUND MID TO LATE WEEK, BUT REMAIN BELOW AVERAGE.
MARINE...
AN UPTICK IN NORTHWEST WINDS OCCURS THIS EVENING AS THE CLIPPER
SYSTEM DEPARTS TO THE EAST, WITH WIND SPEEDS AVERAGING 20 KNOTS
ACROSS CENTRAL LAKE HURON. A WEAK RIDGE MOVING INTO THE CENTRAL
GREAT LAKES THEN ALLOWS WINDS TO BRIEFLY WEAKEN OVERNIGHT INTO EARLY
FRIDAY. ATTENTION REMAINS FOCUSED ON FRIDAY AFTERNOON AND EVENING AS
A STRONG LOW TRACKS JUST NORTH OF LAKE SUPERIOR, POSITIONING ITS LOW-
LEVEL JET OVER LAKE HURON. THIS WILL CAUSE SOUTHERLY WINDS TO
QUICKLY RAMP UP DURING THE EARLY AFTERNOON, REACHING GALE FORCE
ACROSS MUCH OF THE LAKE AND CONTINUING INTO FRIDAY NIGHT.
PROBABILITY HAS TRENDED HIGHER FOR 40+ KT GUSTS AT TIMES, MAINLY MID-
LATE FRIDAY EVENING. THE GALE WATCH HAS BEEN UPGRADED TO A GALE
WARNING. SNOW, OR A RAIN/SNOW MIX, WILL SPREAD OVER THE REGION
FRIDAY NIGHT INTO EARLY SATURDAY AS THE COLD FRONT PASSES THROUGH.
MODERATE NORTHWEST WINDS FOLLOW THIS SYSTEM'S DEPARTURE BUT ARE
EXPECTED TO REMAIN BELOW GALE FORCE AT THIS TIME. NORTHWEST WIND
CONTINUES THROUGH THE WEEKEND AS FRIGID ARCTIC AIR SETTLES INTO THE
REGION. THIS WILL BRING LIKELY LAKE EFFECT SNOW SHOWERS AND
POTENTIAL FOR FREEZING SPRAY EARLY NEXT WEEK.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...GALE WARNING FROM NOON FRIDAY TO 4 AM EST SATURDAY FOR LHZ362-363-
421-441-462>464.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....MR
DISCUSSION...AA
MARINE.......TF
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