426
FXUS63 KDTX 161757
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1257 PM EST MON DEC 16 2024
KEY MESSAGES
- MILD TEMPERATURES WITH RAIN AND DRIZZLE THIS AFTERNOON.
- TEMPERATURES TREND DOWNWARD THROUGH THE WEEK WITH A CHANCE OF
SNOW EARLY WEDNESDAY AND AGAIN THURSDAY NIGHT INTO FRIDAY.
AVIATION
LOW PRESSURE IN NW ONTARIO IS PULLING MILD AND MOISTURE LADEN AIR
INTO THE GREAT LAKES TO PRODUCE ONGOING RAIN SHOWERS AND BORDERLINE
LIFR/IFR CEILING. LIFR FOG THAT WAS WIDESPREAD AT SUNRISE HAS
IMPROVED TO BORDERLINE IFR/MVFR ON AVERAGE AS SOUTH WIND GAINED
TRACTION DURING THE MORNING, HOWEVER IFR CEILING IS ROOTED ACROSS
LOWER MI UNTIL THE MIDWEST COLD FRONT MOVES IN THIS EVENING. RAIN
SHOWERS ARE ALREADY SHIFTING EAST OF THE TERMINAL CORRIDOR AND EXIT
SE MI BY MID AFTERNOON LEAVING LOW CLOUDS WITH PATCHY FOG AND
DRIZZLE INTO EARLY EVENING, EVENTUALLY ALSO SWEPT EASTWARD BY
PASSAGE OF THE COLD FRONT. THE WESTERLY WIND SHIFT QUICKLY REACHES
25 KNOT GUSTS BY MID EVENING WHICH HELPS LIFT CEILING INTO MVFR FOR
THE REST OF TONIGHT INTO TUESDAY MORNING.
FOR DTW... DRIZZLE AND FOG LINGER BEHIND THE PATTERN OF RAIN SHOWERS
EXITING SE MI THIS AFTERNOON. BORDERLINE IFR/LIFR ALSO HOLDS FIRM IN
COMBINATIONS OF CEILING AND VISIBILITY UNTIL THE COLD FRONT MOVES
THROUGH AROUND 02Z. WEST WIND PICKING UP TO 25 KNOT GUSTS AFTER THE
FRONT HELPS LIFT CEILING INTO MVFR FOR THE REMAINDER OF TONIGHT.
DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING AT OR BELOW 5000 FEET TONIGHT AND TUESDAY.
* LOW FOR CIGS/VSBY AT 200 FT AND/OR 1/2 SM THIS AFTERNOON.
PREV DISCUSSION
ISSUED AT 330 AM EST MON DEC 16 2024
DISCUSSION...
A VERY MILD, MOIST AND INCREASINGLY DEEP SOUTHERLY FLOW NOW
ENTRENCHED LOCALLY, WITHIN THE BACKDROP OF LARGE SCALE SUBSIDENCE
HELD WITHIN THE WAKE OF EXITING UPPER RIDGING. PRIME CONDITIONS FOR
NEAR SURFACE SATURATION TO MAINTAIN WIDESPREAD VERY LOW STRATUS AND
AREAS OF DENSE FOG THROUGH THE PRE-DAWN HOURS. LATEST OBSERVATIONAL
TRENDS OFFER A MYRIAD OF VISIBILITY RESTRICTIONS OVERALL, BUT ENOUGH
AREAS REMAIN RESTRICTED AT/BELOW HALF A MILE TO SUPPORT CARRYING THE
ADVISORY OUT THROUGH DAYBREAK AND GRAB THE MORNING COMMUTE.
EXPANSIVE LOW STRATUS TO REMAIN A FIXTURE THROUGHOUT THE DAYLIGHT
PERIOD GIVE THE MOISTURE PROFILE, BUT WITH ENOUGH MIXING AS DIURNAL
PROCESSES GAIN TRACTION TO EASE VISIBILITY RESTRICTIONS WITH TIME
THROUGH THE FIRST HALF OF THE DAY.
ONGOING WARM AIR ADVECTION PEAKS THIS AFTERNOON WITH H8 TEMPERATURES
CRESTING NEAR 7C. THIS PROCESS LENDS TO ANOTHER ROUND OF MEANINGFUL
MOIST ISENTROPIC ASCENT, PROVIDING A HIGH PROBABILITY FOR LIGHT
RAIN/DRIZZLE TO LIFT NORTHEAST ACROSS THE REGION - MAINLY BETWEEN
15Z AND 22Z. SUFFICIENT BOUNDARY LAYER WARMING WILL OFFER A MODEST
COUNTER TO THE LACK OF INSOLATION AND INCREASING SHOWER COVERAGE,
BRINGING HIGHS INTO THE MID 40S TO LOWER 50S RANGE. TRAILING COLD
FRONT ARRIVES EARLY TONIGHT. FRONTAL TIMING MAY LEAVE A BRIEF WINDOW
FOR RENEWED FOG DEVELOPMENT WITHIN THE FIRST FEW HOURS OF SUNSET,
BEFORE ENSURING COLD AIR ADVECTION AND ASSOCIATED MIXING EFFECTIVELY
DRY THE LOWEST LAYERS. NOTED UPTICK IN THE OVERALL WIND PROFILE
OVERNIGHT, ALLOWING FOR SOME GUSTINESS OF POST-FRONTAL WESTERLY FLOW
/25-30 MPH/ BUT GENERALLY CONTAINED GIVEN LACK OF GREATER MIXING
DEPTH OR A STRONGER PUSH OF COLDER AIR.
BENIGN WX CONDITIONS TUESDAY WITH LINGERING GUSTINESS /25-30 MPH/ TO
WEST FLOW AND TEMPERATURES STILL EDGED ABOVE AVERAGE WITH RESIDENT
THERMAL PROFILE OF PACIFIC ORIGIN. ELONGATED UPPER TROUGH THEN
ARRIVES LATE TUESDAY NIGHT INTO WEDNESDAY. BETTER HEIGHT FALLS STILL
PROJECTED TO HOLD SOUTH WITH THIS LEAD FEATURE, BUT THERE REMAINS A
WEAKER SIGNAL FOR ASCENT TIED TO AN INITIAL COLD FRONTAL PASSAGE AND
PERIOD OF DCVA. THIS WILL BRING AT LEAST A MODERATE PROBABILITY FOR
A LIGHT QPF EVENT TO EMERGE CENTERED ON WEDNESDAY MORNING. MODEL
SOLUTION SPACE STILL DISPLAYING GREATER VARIABILITY IN PLACEMENT AND
SCALE OF THE OVERALL RESPONSE, BUT GENERALLY CONTINUE TO TREND
TOWARD A PRECIPITATION TYPE OF SNOW/MELTING SNOW AS FREEZING LEVELS
DIP ADEQUATELY WITH TEMPERATURES PARKED IN THE 31-33 DEGREE RANGE.
ANALYSIS OF ENSEMBLE DATA POINTS TO A HIGHER PROBABILITY FOR AN
ACCUMULATION POTENTIAL OF LESS THAN AN INCH, BUT WITH A SMALLER
SUBSET PROVIDING A MORE FOCUSED FGEN RESPONSE LENDING TO SOME
LOCALLY HIGHER QPF. TEMPERATURES DRIFT INTO THE MIDDLE 30S BRIEFLY
LATE DAY, BEFORE A TRAILING PV FEATURE OF POLAR ORIGIN ARRIVES
WEDNESDAY EVENING. PLAUSIBLE THE MAGNITUDE OF THE FRONTAL
CONVERGENCE AND HEIGHT FALLS GENERATE A BRIEF PERIOD OF SNOW SHOWERS
AS TEMPERATURES DROP THROUGH THE FIRST HALF OF THE NIGHT, BUT A
PROGRESSIVE TRANSITION TOWARD DRIER NORTHWEST FLOW APPEARS TO LIMIT
THE RESPONSE AND CONFINE ANY LES CONTRIBUTION TO THE WEST/NORTHWEST.
ATTENTION TURNS TO BEHAVIOR OF THE NEXT NORTHERN STREAM PV ANOMALY
PROJECTED TO AMPLIFY UPON ARRIVAL FOR THE END OF THE WEEK. THIS
FEATURE STILL MORE THAN 48 HOURS OUT FROM APPROPRIATE SAMPLING, SO
HIGH LIKELIHOOD FOR FLUCTUATION ACROSS THE SOLUTION SPACE REGARDING
TRAJECTORY, MAGNITUDE AND PACE OF THE GOVERNING LARGE SCALE
FEATURES. IN GENERAL, FAVORABLE UNDERLYING ENVIRONMENT FOR A SWATH
OF ACCUMULATING SNOW TO EMERGE ALONG THE EAST/NORTH FLANK OF A
SOUTHEASTWARD PROJECTING WAVE ACROSS PORTIONS OF THE GREAT LAKES
WITHIN THE THURSDAY NIGHT/FRIDAY WINDOW. PASSAGE OF THIS SYSTEM WILL
DRAW NOTABLY COLDER CONDITIONS BACK INTO THE REGION FOR THE UPCOMING
WEEKEND.
MARINE...
MODERATE SOUTHERLY FLOW (20-30 KNOTS) TODAY AHEAD OF A STRONG COLD
FRONT, ATTACHED TO LOW PRESSURE TRACKING THROUGH ONTARIO AND NEAR
JAMES BAY. THIS COLD FRONT WILL BRING RAIN SHOWERS, AS IT SWINGS
THROUGH THE CENTRAL GREAT LAKES EARLY THIS EVENING. TIGHT PRESSURE
GRADIENT WITH 850 MB TEMPS LOWERING TO AROUND -8 C LOOKS SUPPORTIVE
OF WIND GUSTS IN THE 30 TO 35 KNOT RANGE OVER CENTRAL AND NORTHERN
LAKE HURON, LATE MONDAY NIGHT INTO EARLY TUESDAY MORNING. HOWEVER,
GUSTS TO GALES APPEAR TO BE BRIEF, AS THE PRESSURE GRADIENT QUICKLY
RELAXES DURING THE DAY ON TUESDAY. THUS, CONTINUES TO LOOK LIKE A
GALE WATCH OR WARNING WILL NOT BE NEEDED.
AN EVEN STRONGER COLD FRONT LOOKS TO BE MOVING THROUGH ON WEDNESDAY,
AND NORTHERLY WINDS LATE WEDNESDAY THROUGH THURSDAY MORNING WILL
LIKELY REACH INTO THE 20 TO 30 KNOT RANGE, BUT ULTIMATELY INFLUENCED
BY THE STRENGTH AND POSITION OF LOW PRESSURE TRACKING ALONG THE OHIO
RIVER. A RIDGE OF HIGH PRESSURE QUICKLY FOLLOWS, ALLOWING FOR A
PERIOD OF LIGHT WINDS TO END THE WORK WEEK.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 4 PM EST TUESDAY FOR
LHZ421-422.
SMALL CRAFT ADVISORY UNTIL 4 PM EST TUESDAY FOR LHZ441>443.
DENSE FOG ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LHZ441>443-
462>464.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....BT
DISCUSSION...MR
MARINE.......SF
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