460
FXUS63 KDTX 160830
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
330 AM EST MON DEC 16 2024
KEY MESSAGES
- DENSE FOG ADVISORY IN EFFECT THROUGH 10 AM. AREAS OF DENSE FOG
WILL PERSIST THROUGH THE MORNING COMMUTE, BEFORE GRADUALLY
LIFTING.
- WIDESPREAD LIGHT RAIN AND DRIZZLE TODAY WITH VERY MILD CONDITIONS.
- TEMPERATURES TREND DOWNWARD THROUGH THE WEEK WITH A CHANCE OF
SNOW EARLY WEDNESDAY AND AGAIN THURSDAY NIGHT INTO FRIDAY.
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.
PREV DISCUSSION
ISSUED AT 1142 PM EST SUN DEC 15 2024
AVIATION...
FOG WILL PERSIST OVERNIGHT INTO MONDAY MORNING WITH LIFR/VLIFR CIGS
AND VSBYS COMMON. AN INCREASING SOUTHERLY GRADIENT FLOW WILL BRING
SOME MINOR IMPROVEMENT TO CIGS/VSBYS, BUT MAIN CLEARING WILL COME AS
SHOWERS WORK BACK INTO THE AREA MIDDAY ALONG A FRONTAL BOUNDARY.
VSBYS WILL IMPROVE FIRST WITH CIGS FOLLOWING SUITE TO A LESSER
DEGREE WITHIN INCREASING SOUTHWEST FLOW BEHIND THIS FRONT.
FOR DTW...FOG WILL PERSIST OVERNIGHT INTO MONDAY MORNING WITH
LIFR/VLIFR CONDITIONS. SHOWERS RETURN MIDDAY MONDAY WITH SLOWLY
IMPROVING CIGS/VSBYS, ESPECIALLY AFTERNOON INTO EVENING.
DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILINGS AT OR BELOW 5000 FEET THROUGH MONDAY EVENING.
* HIGH IN PRECIPITATION BEING ALL RAIN.
* HIGH FOR CIGS/VSBY TO FALL BELOW 200 FT AND/OR 1/2 SM OVERNIGHT,
MEDIUM INTO MONDAY MORNING.
DTX WATCHES/WARNINGS/ADVISORIES
MI...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ047>049-
053>055-060>063-068>070-075-076-082-083.
LAKE HURON...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR LHZ441>443-
462>464.
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.
LAKE ST CLAIR...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR LEZ444.
DISCUSSION...MR
MARINE.......SF
AVIATION.....DG
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