928  
FXUS63 KDTX 200752  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
352 AM EDT WED AUG 20 2025  
   
KEY MESSAGES  
 
- SEASONABLE TEMPERATURES AND DRY WEATHER EXPECTED TODAY THROUGH  
FRIDAY.  
 
- RAIN CHANCES RETURN THIS WEEKEND AS LOW PRESSURE DRAGS A COLD FRONT  
THROUGH THE AREA.  
 
 
   
DISCUSSION  
 
OVERCAST SKIES BLANKET MUCH OF LOWER MICHIGAN THIS MORNING AS LOW  
LEVEL MOISTURE CONTINUES TO WRAP INTO THE WESTERN QUADRANTS OF THE  
DEPARTING SURFACE LOW. GRADIENT FLOW BETWEEN 5-10 KNOTS HAS KEPT  
MOISTURE ELEVATED TO SUPPORT LOW STRATUS RATHER THAN FOG. THE  
THICKER LAYER OF SYNOPTIC MOISTURE WILL GRADUALLY FADE THROUGH THE  
MORNING, ONLY TO BE REPLENISHED BY LAKE HURON MOISTURE ADVECTION  
WHICH KEEPS A HEALTHY COVERAGE OF CLOUD COVER THROUGH MOST OF THE  
DAYLIGHT HOURS. TEMPERATURES THUS LIKELY TO STAY IN THE MID 70S,  
WITH A FEW SPOTS IN THE UPPER 70S IN THE SAGINAW VALLEY/URBAN  
FOOTPRINT.  
 
CLOUD COVER WANES OVERNIGHT WHILE PW DROPS BELOW 1" TO HIGHLIGHT THE  
VERY DRY AIRMASS ADVECTING INTO THE REGION. TEMPERATURES MODERATE  
SLIGHTLY THROUGH THE REST OF THE WORK WEEK AS THE SUBSIDENCE  
INVERSION GRADUALLY BREAKS DOWN. HIGH TEMPERATURES TREND TOWARD  
NORMAL, WITH HIGHS IN THE UPPER 70S ON THURSDAY AND LOW 80S BY  
FRIDAY. DRY CONDITIONS AND PLENTY OF SUNSHINE RESULT IN A PLEASANT  
COUPLE DAYS OF LATE AUGUST WEATHER ACROSS SE MICHIGAN.  
 
NEXT CHANCE FOR RAIN ARRIVES THIS WEEKEND, WITH THE PARENT WEATHER  
SYSTEM ORGANIZING WEST OF THE MISSISSIPPI RIVER OVER THE NEXT COUPLE  
OF DAYS. STRONG RIDGING OVER WESTERN CONUS HAS LED TO AN ANOMALOUS  
THERMAL RIDGE CHARACTERIZED BY 850MB TEMPERATURES OF 25-30 C AS FAR  
NORTH AS ALBERTA/SASKATCHEWAN (AOA MAXIMUM CLIMATOLOGY PER NAEFS). A  
STRONG UPPER LOW WILL TRACK EASTWARD THROUGH THE CANADIAN PROVINCES  
AND EVENTUALLY ENGAGE THIS WARM/UNSTABLE AIRMASS TO INDUCE  
CYCLOGENESIS IN THE LEE OF THE CANADIAN ROCKIES THURSDAY NIGHT. THE  
LOW WILL THEN TRACK TOWARDS JAMES BAY THIS WEEKEND AND DRAG A COLD  
FRONT ACROSS THE GREAT LAKES IN ITS WAKE. TIMING OF THE FRONT LOOKS  
TO COINCIDE WITH PEAK HEATING, BUT LACKLUSTER MOISTURE CONVERGENCE  
AHEAD OF THE FRONT REALLY CUTS INTO INSTABILITY PROSPECTS AND QPF.  
THUNDERSTORM CHANCES WILL BE GREATEST OVER THE THUMB REGION WHERE  
THE LAKE INFLUENCE PROVIDES A SLIGHT ADVANTAGE IN BOUNDARY LAYER  
MOISTURE.  
 
PASSAGE OF THE COLD FRONT WILL MARK THE TRANSITION TO A MUCH COOLER  
AIRMASS AS THE JAMES BAY LOW STALLS THROUGH EARLY NEXT WEEK. COOL  
NORTHWEST FLOW ACROSS THE SEASONABLY WARM WATERS OF LAKE  
SUPERIOR/LAKE MICHIGAN WILL GENERATE PERIODS OF CLOUD COVER/SHOWER  
POTENTIAL WHILE TEMPERATURES HOLD IN THE LOW TO MID 70S.  
 
 
   
MARINE  
 
PREVAILING NORTHEAST WIND AFFECTS THE AREA TODAY AS LOW PRESSURE  
TRACKS INTO THE EASTERN GREAT LAKES. THE PEAK IN WIND WILL BE THIS  
AFTERNOON ACROSS THE SOUTHERN LAKE HURON BASIN AND SAGINAW BAY WHERE  
WINDS WILL REACH 15 TO 20 KNOTS WITH GUSTS UP TO 25 KNOTS. A SMALL  
CRAFT ADVISORY REMAINS IN EFFECT FOR ALL NEARSHORE WATERS FROM  
SAGINAW BAY TO PORT HURON AS WAVES BUILD INTO THE 3 TO 5 FOOT RANGE.  
WIND MAGNITUDE AND WAVE HEIGHTS WILL GRADUALLY DECREASE THROUGH  
TONIGHT. LIGHTER NORTHEAST WIND PERSISTS ACROSS THE REGION INTO  
THURSDAY AS HIGH PRESSURE BUILDS IN ACROSS THE NORTHERN GREAT LAKES.  
WIND THEN SHIFTS TO SOUTHWEST ON FRIDAY AHEAD OF THE NEXT COLD FRONT  
SET TO ARRIVE ON SATURDAY. A PERIOD OF GUSTY CONDITIONS LOOKS  
INCREASINGLY LIKELY BY THIS WEEKEND AS ROBUST COLD AIR ADVECTION  
BEGINS TO WORK INTO THE REGION.  
 
 
   
PREV DISCUSSION  
 
ISSUED AT 1134 PM EDT TUE AUG 19 2025  
 
AVIATION...  
 
ONGOING SHALLOW COOL AIR ADVECTION AND AMPLE LOW LEVEL MOISTURE HAS  
LED TO A WIDESPREAD LOW STRATUS. OBSERVATIONAL TRENDS AND RECENT  
MODEL GUIDANCE SUGGEST A PREVAILING LOW END MVFR AND IFR CEILINGS  
THROUGH DAYBREAK. THE NORTHERN GRADIENT FLOW WILL SUSTAIN WINDS  
AROUND 10 KNOTS AND WILL BE A LIMITING FACTOR FOR MUCH IF ANY FOG.  
SOME BRIEF MINOR VISIBILITY RESTRICTION MAY HOWEVER BE POSSIBLE  
WITHIN ANY AREAS OF EARLY MORNING DRIZZLE. LOW LEVEL DRY AIR  
ADVECTION AND DIURNAL HEATING/MIXING WILL RESULT IN A STEADY  
IMPROVING TREND IN CEILING HEIGHTS DURING THE DAY WEDNESDAY. SOME  
VEERING OF THE LOW LEVEL WINDS FIELDS TOWARD THE NORTH-NORTHEAST WED  
AFTERNOON AND EVENING MAY SUSTAIN A STRATO FIELD ACROSS PORTIONS OF  
SE MI INTO WED NIGHT GIVEN THE ADDED MOISTURE FLUX OFF THE LAKES.  
 
FOR DTW/D21 CONVECTION...NO THUNDERSTORMS ARE FORECAST THROUGH THE  
TAF PERIOD.  
 
THRESHOLD PROBABILITIES...  
 
* HIGH FOR CEILINGS AOB 5000 FEET TONIGHT AND WEDNESDAY.  
 
 
   
DTX WATCHES/WARNINGS/ADVISORIES  
 
MI...BEACH HAZARDS STATEMENT FROM 8 AM EDT THIS MORNING THROUGH THIS  
EVENING FOR MIZ049-055-063.  
 
LAKE HURON...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 10 PM EDT THIS  
EVENING FOR LHZ421-422-441>443.  
 
LAKE ST CLAIR...NONE.  
MICHIGAN WATERS OF LAKE ERIE...NONE.  
 
 
 
 
DISCUSSION...MV  
MARINE.......TF  
AVIATION.....SC  
 
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE  
AT WWW.WEATHER.GOV/DETROIT.  
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