801
FXUS63 KDTX 120730
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
330 AM EDT FRI SEP 12 2025
KEY MESSAGES
- AREAS OF FOG, SOME DENSE, THIS MORNING ESPECIALLY THE
THUMB/SAGINAW VALLEY.
- DRY AND WARM AGAIN TODAY WITH HIGHS AROUND 80.
- CHANCE OF SCATTERED SHOWERS AND AN ISOLATED EMBEDDED THUNDERSTORM
SATURDAY MORNING THROUGH LATE AFTERNOON.
- MUCH ABOVE NORMAL HIGHS WITH CONTINUING DRY WEATHER SUNDAY THROUGH
MIDWEEK.
DISCUSSION
LIGHT EASTERLY FLOW OFF LAKE HURON HAS SUPPORTED A ROBUST FOG
RESPONSE ACROSS MUCH OF THE THUMB/SAGINAW VALLEY LAST NIGHT WITH
DEVELOPMENT MUCH PATCHIER FOR THE REST OF SE MI. AREAS OF FOG BURN
OFF THIS MORNING AS THE REGION STILL HOLDS UNDER THE INFLUENCE OF
HIGH PRESSURE NOW CENTERING OVER SOUTHWESTERN ONTARIO. LARGELY A
PERSISTENCE FORECAST TODAY AS A RESULT WITH WINDS REMAINING VERY
LIGHT NOW OUT OF A GENERALLY SOUTHERLY DIRECTION (RANGING SW TO SE)
WITH SKIES TURNING PARTLY CLOUDY FROM DIURNAL CUMULUS. RIDGE AXIS
SHIFT TO OUR EAST AND THE SUBSEQUENT WIND SHIFT SETS UP VERY MODEST
WAA (850MB TEMPS NUDGE UP 1-2C) SUPPORTING SLIGHTLY WARMER HIGHS
COMPARED TO THURSDAY WITH MOST AREAS LIKELY REACHING AROUND 80 IF
NOT LOWER 80S. COOLER NIGHT (LOWS IN THE 50S) IN STORE AGAIN TONIGHT
AS SKIES CLEAR OVER VERY LIGHT TO NONEXISTENT WINDS LEADING TO
EFFICIENT RADIATIVE COOLING.
CENTRAL CONUS RIDGING AMPLIFIES TONIGHT/SATURDAY AS A WEAK SHORTWAVE
RIDES OVER TOP TOWARDS THE WESTERN GREAT LAKES. BULK OF MODEL
GUIDANCE CONTINUES TO ADVERTISE THIS WAVE DIVING SOUTHEAST ACROSS
SOUTHERN LAKE MICHIGAN INTO NORTHERN IN/FAR SOUTHWESTERN MI SATURDAY
MORNING. WITH NOCTURNAL LOW LEVEL JET FORCING OVER THE UPPER
MISSISSIPPI NOT KEEPING PACE TO THE ASSOCIATED CLUSTER OF
SHOWERS/STORMS, THIS CONVECTION BEGINS TO DECAY WHILE CROSSING THE
STATE. ADDITIONALLY THE MAJORITY OF RAIN HOLDS TO OUT SOUTHWEST
GIVEN THE SHORTWAVE TRACK. END RESULT LOCALLY IS A LOWER END CHANCE
(20-30%) SATURDAY MORNING THRU LATE AFTERNOON FOR SCATTERED SHOWERS
AND ISOLATED EMBEDDED THUNDER.
OTHERWISE EXTENDED PERIOD OF DRY, SEASONABLY HOT WEATHER CONTINUES
NEXT WEEK AS AN OMEGA BLOCK FORMS ACROSS THE CONUS WITH THE RIDGE
FOCUSED OVER THE MIDWEST/GREAT LAKES. HIGHS SUNDAY THROUGH
POTENTIALLY THURSDAY TOP OUT IN THE MID TO UPPER 80S, A SOLID 10+
DEGREES ABOVE MID-SEPTEMBER NORMALS. COOLER OVERNIGHT LOWS IN THE
50S ALSO LOOK TO PERSIST DURING THIS TIMEFRAME THANKS TO HIGH
PRESSURE PROMOTING CLEAR NIGHT SKIES AND LIGHT WINDS.
MARINE
PATCHY FOG THAT DEVELOPED NEAR THE SHORELINE EARLY THIS MORNING WILL
BEGIN TO MIX OUT AFTER SUNRISE. DRY CONDITIONS AND GRADUALLY VEERING
WIND PROFILES THEN CHARACTERIZE MOST OF THE DAYTIME HOURS AS HIGH
PRESSURE DRIFTS TOWARD NEW ENGLAND. HUDSON BAY LOW PRESSURE CARVES
INTO THE EASTERN GREAT LAKES THIS WEEKEND, SENDING AN UPPER LEVEL
DISTURBANCE INTO LAKE HURON SATURDAY FOLLOWED BY A COLD FRONT
SATURDAY NIGHT. BOTH FEATURES GENERATE LOW COVERAGE/LOW IMPACT
SHOWER POTENTIAL AS THEY STRUGGLE TO ACCESS MOISTURE. A SECOND HIGH
PRESSURE CENTER OVER ONTARIO EXPANDS BACK INTO THE GREAT LAKES
SUNDAY AND PERSISTS THROUGH EARLY NEXT WEEK MARKING THE RETURN OF
DRY WEATHER AND CONTINUING THE STRETCH OF FAVORABLE MARINE
CONDITIONS.
PREV DISCUSSION
ISSUED AT 1157 PM EDT THU SEP 11 2025
AVIATION...
SURFACE TD REMAINS ELEVATED TONIGHT AFTER A DAY OF NE WIND OFF LAKE
HURON. THIS COMBINES WITH CLEAR SKY AND LIGHT/CALM WIND FOR AN
EFFECTIVE RADIATIONAL COOLING AND FOG SETUP LATE TONIGHT AND EARLY
IN THE MORNING. LATE EVENING TEMPERATURE TRENDS FAVOR THE MBS AND
FNT AREAS FOR IFR/LIFR VISIBILITY WHERE T/TD SPREAD IS NARROWING
MORE QUICKLY COMPARED TO THE SLOWER PACE IN THE MORE URBANIZED DTW
METRO WHERE BORDERLINE MVFR/IFR IS MORE LIKELY. FULL MORNING SUN
THEN HELPS QUICKLY DISSIPATE VISIBILITY RESTRICTION LEADING TO
ANOTHER ROUND OF VFR CUMULUS IN THE AFTERNOON.
FOR DTW/D21 CONVECTION... NO THUNDERSTORMS TONIGHT THROUGH FRIDAY.
THRESHOLD PROBABILITIES...
* NONE.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...KDK
MARINE.......MV
AVIATION.....BT
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