130
FXUS63 KDTX 211202
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
702 AM EST FRI NOV 21 2025
KEY MESSAGES
- MAINLY DRY CONDITIONS RETURN THIS WEEKEND WITH A WARMING TREND BY
SUNDAY.
- INCREASED PRECIPITATION CHANCES ARRIVE DURING THE FIRST HALF OF
NEXT WEEK WITH COLDER TEMPERATURES RETURNING FOR THE LATTER HALF.
AVIATION
A COLD FRONT CROSSING LOWER MI LEAVES BEHIND BROKEN COVERAGE OF MVFR
STRATUS THROUGH THE MORNING. POCKETS OF IFR AND PATCHES OF DRIZZLE
AND FOG LINGER BRIEFLY ALONG AND AHEAD OF THE FRONT IN AIR HAVING
GREATER MOISTURE CONTENT, BUT WHICH MOVE EAST OF THE TERMINAL
CORRIDOR WITH THE FRONT. ADEQUATE BOUNDARY LAYER LAPSE RATE
INDICATED IN MODEL SOUNDINGS THEN ALLOWS A MID MORNING CLOUD
RESPONSE TO DAYTIME HEATING FOLLOWED BY OPTIMISTIC CLOUD TRENDS FOR
THIS AFTERNOON THAT ARE SUPPORTED BY UPSTREAM SATELLITE AND SURFACE
OBSERVATIONS. FURTHER DRYING OF THE AIR AND ADDITIONAL DAYTIME
HEATING LEAD TO A DECREASING CLOUD TREND INTO THIS EVENING. MIDWEST
HIGH PRESSURE THEN BUILDS INTO LOWER MI LATE TONIGHT WHILE LOW
PRESSURE SLIDES THROUGH THE OH/TN VALLEYS. THIS RESULTS IN THE
NORTHERN FRINGE OF HIGH CLOUDS MOVING INTO LOWER MI WITH A FEW
CLUSTERS OF STRATOCU PTK NORTHWARD AS CLOUD LAYER WIND TURNS NW INTO
SATURDAY MORNING.
DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING 5000 FT OR LESS THIS MORNING, MEDIUM THIS
AFTERNOON AND LOW TONIGHT.
PREV DISCUSSION
ISSUED AT 356 AM EST FRI NOV 21 2025
DISCUSSION...
YESTERDAY'S LOW STRATUS DECK HAS HELD FIRMLY IN PLACE THROUGH THE
OVERNIGHT HOURS, TRAPPED BELOW A SHARP INVERSION SITTING AT ~5.0 KFT
AGL. MANY LOCATIONS HAVE SEEN THIS STRATUS DECK BRIEFLY BUILD DOWN
TO THE SURFACE, ALTHOUGH FOG DEVELOPMENT HAS FAILED TO BECOME
WIDESPREAD WITHIN THE TURBULENT BOUNDARY LAYER (WINDS AROUND 7-10
KNOTS). POCKETS OF FOG THAT HAVE BEEN ABLE TO DEVELOP WILL BEGIN TO
MIX OUT WITH DAYTIME HEATING, ALSO AIDED BY THE PASSAGE OF A COLD
FRONT THIS MORNING. THE FRONT HAS STARTED MAKING ITS WAY ACROSS
LOWER MICHIGAN, DENOTED BY A SUBTLE SHIFT TO WESTERLY FLOW AND WEAK
RADAR RETURNS (DRIZZLE). NOT EXPECTING MUCH OF A TEMPERATURE SHIFT
WITH THIS FROPA, AS THE COLD AIR IS QUITE SHALLOW AND WILL EASILY BE
OVERCOME BY DAYTIME HEATING. A MORE NOTABLE SHIFT WILL BE THE INFLUX
OF A DRIER AIRMASS, WITH DEWPOINTS EXPECTED TO DROP FROM MID-40S AT
PRESS TIME INTO THE MID-30S BY THIS AFTERNOON. DRY AND STABLE
CONDITIONS ALOFT COUPLED WITH THE DRYING BOUNDARY LAYER WILL AFFORD
AT LEAST PARTIAL EROSION OF THE CLOUD LAYER BY THIS AFTERNOON.
DAYTIME HIGHS IN THE UPPER 40S TO LOW 50S EXPECTED.
SE MICHIGAN RESIDES BELOW A REGION OF CONFLUENCE ALOFT, AT THE
INFLECTION POINT OF THE NORTHERN AND SOUTHERN STREAM AIRMASSES. A
ROUGHLY 10 C TEMPERATURE DIFFERENCE EXISTS FROM THE MACKINAC STRAITS
TO THE OHIO BORDER, EXEMPLIFYING THE BAROCLINICITY THAT EXISTS
OVERHEAD. THIS MAKES FOR AN ACTIVE PATTERN AROUND THE GREAT LAKES,
ALTHOUGH SO FAR WE HAVE BEEN FLOATING BETWEEN THE TWO STORM TRACKS.
THIS LOOKS TO BE THE CASE THROUGH THE WEEKEND AS WELL, WITH THE
SOUTHERN STREAM SYSTEM GETTING SHOVED SOUTH/EAST OF THE STATE LINE
AND A NORTHERN STREAM SYSTEM LACKING THE MOISTURE DEPTH TO GENERATE
MEASURABLE PRECIPITATION DESPITE MORE DIRECT FORCING. WHILE LOW END
CHANCES EXIST FOR A SHOWER TO CLIP THE OUTER EDGES OF THE CWA,
LOOKING AT AN OVERALL DRY WEEKEND ESPECIALLY AS HIGH PRESSURE BUILDS
INTO THE REGION SUNDAY. COLDEST PORTIONS OF THE THERMAL TROUGH
REMAIN WELL OVER CANADA, LEAVING SE MICHIGAN RIGHT ON THE CUSP OF
THE TRANSIENT 0 C ISOTHERM (H8) THROUGH THE WEEKEND. HIGHS ON
SATURDAY WILL BE IN THE LOW-MID 40S, WITH A WARM UP INTO THE LOW-MID
50S FOR SUNDAY.
THE MAIN LONG-TERM ITEM OF NOTE IS A PAIR OF PACIFIC WAVES THAT WILL
IMPACT THE GREAT LAKES MIDDLE OF NEXT WEEK, SUPPORTING AN EXTENDED
STRETCH OF PRECIPITATION CHANCES FROM MID- TO LATE-WEEK. THERE IS
HIGH CONFIDENCE IN ABOVE AVERAGE TEMPERATURES EXTENDING THROUGH THE
EARLY HALF OF NEXT WEEK AS THE PATTERN AMPLIFIES AND LOW LEVEL THETA-
E ADVECTION RAMPS UP. ENSEMBLE MEAN HIGH TEMPERATURES ARE IN THE MID-
50S FOR MONDAY, AND LOW 50S FOR TUESDAY. MODEL VARIANCE FOR 500MB
HEIGHTS AND 850MB TEMPERATURES REALLY STARTS TO DIVERGE AFTER 00Z
WEDNESDAY, HIGHLIGHTING THE TIMING UNCERTAINTY OF THIS PATTERN. AT
SOME POINT MID-WEEK, A STRONG COLD FRONT IS FORECAST TO TRACK ACROSS
THE AREA BRINGING A SURGE OF COLDER CANADIAN AIR INTO THE GREAT
LAKES FOR THE HOLIDAY AND HOLIDAY WEEKEND. THIS WILL MARK A RETURN
TO WINTER-LIKE CONDITIONS.
MARINE...
COLD FRONTAL PASSAGE LATE LAST NIGHT/EARLY THIS MORNING SETS THE
STAGE FOR MODERATE NORTHWESTERLY FLOW TODAY. GRADIENT ISN'T
PARTICULARLY GIVEN THE REGION RESIDING ON THE FRINGE OF THE NORTHERN
ONTARIO LOW KEEPING GUSTS ACROSS NORTHERN LAKE HURON UNDER 30KTS.
WINDS ARE WEAKER FURTHER SOUTH YOU ARE WITH PEAK GUSTS ONLY TOPPING
OUT AROUND 15-20KTS FOR THE SOUTHERN LAKES. WINDS SHIFT MORE NORTH-
NORTHWEST TONIGHT ALLOWING HIGHER ACTION TO CLIP THE TIP OF THE
THUMB REQUIRING SMALL CRAFT ADVISORIES FOR THE PORT AUSTIN NEARSHORE
WATERS. HIGH PRESSURE THEN BRIEFLY WORKS IN BY LATE TONIGHT BRINGING
LIGHT WINDS TO START THE WEEKEND.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 4 AM EST SATURDAY
FOR LHZ441.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....BT
DISCUSSION...MV
MARINE.......KDK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page