507
FXUS63 KDTX 131926
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
326 PM EDT SAT SEP 13 2025
KEY MESSAGES
- DRIER THIS EVENING WITH DECREASING CLOUD COVER.
- PATCHY FOG POSSIBLE SUNDAY MORNING, ESPECIALLY NEAR THE SHORELINE
OF LAKE ERIE AND LAKE ST. CLAIR.
- MUCH ABOVE NORMAL HIGHS WITH CONTINUING DRY WEATHER NEXT WEEK.
DISCUSSION
SE MICHIGAN RESIDES AT THE INFLECTION POINT OF LOW PRESSURE NEAR
HUDSON BAY AND HIGH PRESSURE BUILDING OVER THE PLAINS. THE INFLUENCE
OF THE TROUGH WAS NOTED IN THE 12Z KDTX RAOB AS A 500MB HEIGHT OF
583 DAM WAS SAMPLED AT KDTX AND 580 DAM AT KAPX. SHOWERS THAT WERE
GENERATED BY THIS SYSTEM HAVE SINCE DEPARTED SOUTHEAST, ALTHOUGH
REMNANT CLOUD COVER REMAINS AS A POCKET OF MID-LEVEL MOISTURE AND
ISENTROPIC ASCENT GLANCE ACROSS THE AREA. CLOUD COVER SHOULD SLOWLY
ERODE THIS EVENING IN FAVOR OF CLEAR SKIES AND RADIATIVE COOLING
OVERNIGHT UNDER THE STABLE SUBSIDENCE INVERSION. DEWPOINTS THIS
AFTERNOON HAVE BEEN NOTABLY HIGHER THAN MOST OF THE HI-RES GUIDANCE,
SUGGESTING PATCHY FOG MAY BE MORE AGGRESSIVE THAN WHAT MODELS ARE
CURRENTLY PREDICTING. WHILE CURRENT GRIDS REFLECT FOG NEAR THE
SHORELINE, THIS MAY NEED TO BE EXPANDED INLAND DEPENDING ON
MOISTURE/CLOUD TRENDS THROUGH THE EVENING.
HEIGHTS BUILD SUNDAY THROUGH TUESDAY AS A SEASONABLY STRONG RIDGE
AXIS SLIDES INTO SE MICHIGAN AND SURFACE HIGH PRESSURE FILLS IN FROM
ONTARIO. 90-100% OF LREF MEMBERS PREDICT 500MB HEIGHTS ABOVE 588
DAM, WHICH IS IN THE 90TH PERCENTILE PER SPC CLIMATOLOGY. THE
BUILDING RIDGE TRANSITIONS TO A REX BLOCK AS AN UPPER LOW DEEPENS
OVER SE CONUS, WITH THE OVERHEAD RIDGE EFFECTIVELY STALLING MULTIPLE
UPSTREAM WAVES WEST OF THE MISSISSIPPI RIVER TO ENSURE DRY WEATHER
THROUGH MID-WEEK. THIS WILL ALSO SUPPORT SEASONABLY WARM CONDITIONS
WITH DAYTIME HIGHS COMFORTABLY CLIMBING INTO THE 80S UNDER PLENTY OF
SOLAR INSOLATION.
BY MID-WEEK, THE RIDGE BEGINS TO BREAK DOWN AS A CLUSTER OF
SHORTWAVES ORGANIZE INTO AN UPPER LOW OVER THE DAKOTAS AND CENTRAL
CANADA. PREDICTABILITY IN THE SYNOPTIC PATTERN LESSENS THROUGH THE
REST OF THE WEEK AS THESE WAVES INTERACT, WITH THE COMPLICATED
PHASING OF THESE FEATURES OFFERING MANY POSSIBLE SCENARIOS. IN
GENERAL, EXPECT A PERIOD OF HEIGHT FALLS AND INCREASED MOISTURE BY
LATE WEEK-NEXT WEEKEND. ENSEMBLE MEMBER STATISTICS SHOW A MARKED
INCREASE IN VARIANCE BY THE WEEKEND, FAVORING A COOL DOWN AND
CHANCES FOR RAIN.
MARINE
A RIDGE OF HIGH PRESSURE WILL BUILD IN THROUGH SUNDAY AND WILL HOLD
THROUGH THE THE MIDDLE OF THE WEEK, BRINGING AN EXTENDED PERIOD OF
DRY WEATHER ALONG WITH LIGHT WINDS. WINDS DIRECTION WILL TURN MORE
UNIFORM THROUGH THE DAY TOMORROW FROM THE NORTHEAST, BRINGING SOME
LOCALIZED ELEVATED GUSTS NEARING 20 KNOTS INTO THE SAGINAW BAY.
THESE LOCALIZED HIGHER WINDS WILL SUBSIDE THROUGH MONDAY MORNING.
PREV DISCUSSION
ISSUED AT 203 PM EDT SAT SEP 13 2025
AVIATION...
AREA OF HIGH PRESSURE BRIEFLY DISRUPTED BY A TROUGH PASSING OVER THE
REGION THIS MORNING. OVERCAST MID CLOUDS FILLED THE SKIES WITH ONLY
A FEW LIGHT SHOWERS. SKIES HAVE BEGUN CLEARING RESULTING IN MORE OF
A SCT-BKN MID CLOUD DECK. SOME CU HAS BEGUN TO POP UP ACROSS
NORTHERN MI BUT IS MAINLY ABOVE 6KFT SO SHOULDN'T RESULT IN ANY
CHANGE IN FLIGHT CATEGORY. LIGHT WINDS AND CLEAR SKIES THIS TIME OF
YEAR GIVES THE POTENTIAL FOR PATCHY FOG DEVELOPMENT EARLY SUNDAY
MORNING. GUIDANCE IS NOT VERY SUPPORTIVE FOR FOG THOUGH WITH ONLY
THE NAM SHOWING A GOOD CHANCE. ALL THE OTHER SOUNDINGS ARE QUITE DRY
AND SURFACE WINDS ARE NOT PERSISTENT ENOUGH OUT OF THE EAST OFF THE
LAKES TO INCREASE BOUNDARY LAYER MOISTURE. SO WILL LEAVE OUT OF THE
TAFS THIS FORECAST AND ASSESS TEMP/DEWPOINT TRENDS HEADING INTO
TONIGHT.
FOR DTW/D21 CONVECTION... THUNDERSTORMS ARE NOT ANTICIPATED THROUGH
THE WEEKEND.
THRESHOLD PROBABILITIES...
* NONE.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...MV
MARINE.......AM
AVIATION.....DRK
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