053
FXUS63 KDTX 152242
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
542 PM EST SUN DEC 15 2024
KEY MESSAGES
- SCATTERED SHOWERS AND DRIZZLE GIVE WAY TO FOGGY CONDITIONS THIS
EVENING AND OVERNIGHT. POCKETS OF DENSE FOG WILL BE POSSIBLE FOR
PARTS OF THE AREA.
- WIDESPREAD LIGHT RAIN ON MONDAY WITH VERY MILD CONDITIONS.
- TEMPERATURES TREND DOWNWARD THROUGH THE WEEK WITH A CHANCE OF
SNOW ON WEDNESDAY AND AGAIN THURSDAY NIGHT.
AVIATION
ABUNDANT FLOW OF LOW LEVEL MOISTURE WILL CONTINUE AS WINDS VEER FROM
THE EAST AND SOUTHEAST TO SOUTH OVERNIGHT INTO MONDAY. EXPECT LIFR
(SOME VLIFR) CONDITIONS IN CIGS AND/OR VSBYS AS FOG REMAINS IN
PLACE. THERE MAY BE MINOR IMPROVEMENT WITHIN THE SOUTHERLY FLOW
MONDAY AS ADDITIONAL SHOWERS WORK BACK THROUGH THE AREA GENERALLY
BETWEEN 18Z-00Z. MOST NOTABLE LIFTING OF CIGS/VSBYS WILL HOLD OFF
UNTIL AFTER THE FRONT DRIVING THIS AREA OF SHOWERS SWEEPS THROUGH
THE AREA 21Z-00Z.
FOR DTW...FOG WILL PERSIST TONIGHT 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 AFTERNOON.
* HIGH IN PRECIPITATION BEING ALL RAIN THROUGH.
* MEDIUM FOR CIGS/VSBY TO FALL BELOW 200 FT AND/OR 1/2 SM TONIGHT.
PREV DISCUSSION
ISSUED AT 330 PM EST SUN DEC 15 2024
DISCUSSION...
REGIONAL ANALYSIS THIS AFTERNOON HIGHLIGHTS A CLOSED UPPER LOW
TRACKING EAST ACROSS SOUTHERN LOWER MI, BRINGING A POCKET OF LIGHT
SHOWERS AS SURFACE TEMPS SIT IN THE UPPER 30S AND LOWER 40S. THE
SURFACE LOW HAS ALREADY WASHED OUT UPSTREAM AS RAPID HEIGHT RISES
COMMENCE ON THE BACK SIDE OF THE UPPER LOW. THIS PATTERN WILL INDUCE
A LARGE SCALE MID TO UPPER LEVEL SUBSIDENCE RESPONSE OVER THE AREA
TONIGHT. THE RESULTANT STRENGTHENING LOW-LEVEL INVERSION WILL TRAP
ABUNDANT MOISTURE NEAR THE SURFACE, ALLOWING OVERCAST, MISTY/FOGGY,
AND OVERALL DREARY BUT MILD CONDITIONS TO PERSIST THROUGH THE NIGHT.
CONFIDENCE IS GROWING FOR DEVELOPMENT OF AREAS OF DENSE FOG,
SUPPORTED BY UPSTREAM OBSERVATIONS THROUGH TODAY AND HI-RES
GUIDANCE. MUCH OF THE MODEL SIGNAL FOR DENSE FOG IS FOCUSED ALONG
THE GLACIAL RIDGE WHERE SSE FLOW WILL MAINTAIN A GENTLE UPSLOPE
COMPONENT TO BRING HIGHEST CONFIDENCE IN LOW VISIBILITY. IF TRENDS
PLAY OUT THIS EVENING A DENSE FOG ADVISORY MAY BE NEEDED FOR PARTS
OF THE AREA. VISIBILITY HAS ALREADY DROPPED TO LESS THAN 1 MILE HERE
ON THE HILLTOP IN WHITE LAKE.
THE SHORTWAVE RIDGE ALOFT WILL GIVE WAY TO THE NEXT LONGWAVE TROUGH
ARRIVING FROM THE MIDWEST ON MONDAY. THIS WILL TAKE A SLIGHT
NEGATIVE TILT AS LEAD PV ENERGY EMERGES FROM THE SUBGEOSTROPHIC
PORTION OF THE UPPER JET. THE RESULT WILL BE ANOTHER SURGE OF MILD
AIR ON A STRENGTHENING SOUTHWESTERLY LLJ INCREASING 850MB TEMPS TO
BETWEEN 5 AND 8 C. THIS WILL BOOST SURFACE HIGH TEMPS TO THE UPPER
40S TO LOWER 50S. WITH THE SURGE OF MILD AIR COMES ADDITIONAL LOW TO
MID LEVEL MOISTURE ADVECTION AND FOCUSED ISENTROPIC ASCENT,
RESULTING IN WIDESPREAD LIGHT RAINFALL DURING THE DAY. A
COLD/OCCLUDED FRONT THEN TRACKS ACROSS THE AREA MONDAY EVENING WITH
ENERGETIC WESTERLY FLOW WORKING IN AMIDST THE ENSUING COLD
ADVECTION. THIS WILL CAUSE WINDS TO GUST UPWARDS OF 25 TO 35 MPH FOR
A BRIEF PERIOD LATE MONDAY EVENING. LIGHT DRIZZLE MAY LINGER
OVERNIGHT AS LOW-LEVEL MOISTURE IS SLOW TO STRIP OUT.
A BREEZY START TO TUESDAY WILL SEE WINDS EVENTUALLY TAPER OFF DURING
THE AFTERNOON AS A WEAKER PRESSURE PATTERN SETTLES INTO THE SOUTHERN
GREAT LAKES. DRY AIR ADVECTION AND MIXING INTO THE BOUNDARY LAYER
MAY ALLOW FOR SOME EROSION OF THE LOW STRATUS AND BRING A FEW PEEKS
OF SUN LATE IN THE DAY. TEMPERATURES WILL BE ON THE MILD SIDE WITH
HIGHS IN THE UPPER 30S TO LOWER 40S.
WEDNESDAY PRESENTS THE NEXT OPPORTUNITY FOR PRECIP AS THE ARRIVAL OF
AN ARCTIC FRONT COINCIDES WITH THE PASSAGE OF A SOUTHERN STREAM LOW
ALONG THE OHIO/TENNESSEE VALLEYS. SYSTEM RELATIVE STREAMLINES SHOW
THE SOUTHERN SYSTEM'S COLD CONVEYOR BEING DIRECTED UP THE ELEVATED
FRONTAL SLOPE OVER SE MI, RESULTING IN FORCING FOR ASCENT AND PRECIP
PRODUCTION OVERHEAD. THE EVENTUAL COVERAGE/PLACEMENT OF THIS
RELATIVELY NARROW BAND OF PRECIP WILL BE DICTATED BY POSITIONING AND
INTERACTION OF THE UPPER LEVEL FEATURES THAT WILL COME MORE INTO
FOCUS THE NEXT SEVERAL MODEL RUNS, ESPECIALLY AS THE PARENT PACIFIC
AND ARCTIC LOWS MOVE INTO THE UPPER AIR SAMPLING NETWORK. THERMAL
PROFILES DURING THIS PERIOD WOULD FAVOR MAINLY SNOW PTYPE WITH
SURFACE TEMPS IN THE LOWER TO MID 30S SUGGESTING A GOOD DEAL OF
MELTING AND MINIMAL ACCUMULATIONS. THE LATE WEEK OUTLOOK HIGHLIGHTS
FAIRLY HIGH CONFIDENCE IN A CLIPPER SYSTEM TRACKING INTO THE GREAT
LAKES THURSDAY NIGHT, FOLLOWED BY A RETURN TO COLD CONDITIONS
THROUGH NEXT WEEKEND.
MARINE...
SOUTHEAST WINDS OF 15 TO 25 KNOTS CONTINUE OVER LAKE HURON THIS
AFTERNOON, ALLOWING 4+ WAVES TO IMPACT THE NEARSHORE ZONES. WINDS
DIMINISH AND ATTEMPT TO BECOME MORE DUE SOUTHERLY TONIGHT. HOWEVER,
A RENEWED INCREASE AND WINDS TOMORROW, ALONG WITH WAVES BUILDING
BACK UP, HAVE ELECTED TO EXTEND SMALL CRAFT ADVISORIES FOR SOUTHERN
LAKE HURON THROUGH TUESDAY.
RESUMED MODERATE SOUTHERLY FLOW CAN BE EXPECTED WITH ADDITIONAL RAIN
BY MONDAY. COLD FRONT, ATTACHED TO LOW PRESSURE TRACKING THROUGH
ONTARIO AND NEAR JAMES BAY, WILL SWING THROUGH THE CENTRAL GREAT
LAKES EARLY MONDAY 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 UNTIL 4 PM EST TUESDAY FOR LHZ441>443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....DG
DISCUSSION...TF
MARINE.......SF
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