762  
FXUS63 KDTX 110712  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
312 AM EDT THU SEP 11 2025  
   
KEY MESSAGES  
 
- DRY TODAY AND FRIDAY WITH ABOVE NORMAL HIGH TEMPERATURES, BUT  
AREAS OF FOG APPEAR LIKELY TONIGHT.  
 
- CHANCE OF SHOWERS AND SLIGHT CHANCE OF THUNDERSTORMS SATURDAY.  
 
- WARM AND DRY SUNDAY THROUGH WEDNESDAY.  
 
 
   
DISCUSSION  
 
THE UPPER-LEVEL RIDGE AXIS OVER THE WESTERN GREAT LAKES WILL EXTEND  
INTO THE CENTRAL GREAT LAKES THIS EVENING, WITH 500 MB HEIGHTS  
REACHING 584 DAM AND HOLDING THROUGH FRIDAY. THIS SHOULD ENSURE DRY  
CONDITIONS WITH A MODEST WARMING IN THE LOW LEVELS EACH DAY AS 850  
MB TEMPERATURES ARE EXPECTED TO REACH AROUND 12 C THURSDAY, AND THEN  
REACH AND SLIGHTLY EXCEED 13 C ON FRIDAY. THUS, TEMPERATURES IN  
THE LOW TO MID-80S SEEM REASONABLE ON FRIDAY (ASSUMING MORNING FOG  
BURNS OFF IN A TIMELY FASHION).  
 
A STRONG PV ANOMALY/UPPER LEVEL LOW IS ON TRACK TO MOVE THROUGH  
HUDSON BAY ON FRIDAY AND INTO QUEBEC ON SATURDAY. SOUTHEASTERN  
MICHIGAN WILL BE ON THE WESTERN FRINGE OF THE LARGE TROUGH THAT WILL  
SINK SOUTH THROUGH NEW ENGLAND AND EASTERN GREAT LAKES ON SATURDAY.  
A TIGHT BAROCLINIC ZONE IS SETTING UP WITH COMPRESSIONAL WARMING ON  
THE LEE SIDE OF THE ROCKIES EJECTING NORTHEAST FROM THE CENTRAL  
PLAINS. THERE IS A CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS ON  
SATURDAY AS A SHORTWAVE MOVES OUT OF THE NORTHERN ROCKIES AND TRACKS  
THROUGH THE REGION. HOWEVER, THE EXACT TRACK, POSITION, AND AMOUNT  
OF INSTABILITY AND STEEPNESS OF MID LEVEL LAPSE RATES REMAIN IN  
QUESTION. THE NAM IS ONE MOST AGGRESSIVE SOLUTIONS, WITH NOT A WHOLE  
LOT OF SUPPORT FROM OTHER SOLUTIONS. NBM POPS IS STILL INDICATING  
ONLY A CHANCE OF PRECIPITATION.  
 
THE SUMMER-LIKE UPPER LEVEL RIDGE AXIS IS STILL ON TRACK TO MOVE  
OVERHEAD FOR SUNDAY AND MONDAY. 500 MB HEIGHTS ARE PROJECTED TO REACH  
590 DAM (SUPPORTED BY EURO ENSEMBLES), AND CENTER OF THE RIDGE MAY  
HOLD IN PLACE THROUGH MID WEEK, LEADING TO DRY AND WARM CONDITIONS  
SUNDAY-WEDNESDAY.  
 
 
   
MARINE  
 
HIGH PRESSURE DRIFTS FROM ONTARIO TO NEW ENGLAND TODAY AND TOMORROW,  
ENSURING DRY AND CALM MARINE CONDITIONS TO END THE WORK WEEK. LIGHT  
NE WINDS GRADUALLY VEER TO THE SW BY FRIDAY AS THE HIGH DEPARTS. SW  
FLOW ADVECTS ELEVATED PORTIONS OF A WARM FRONT INTO THE AREA FRIDAY  
AFTERNOON, INTRODUCING LOW END SHOWER CHANCES FRIDAY NIGHT INTO  
SATURDAY ALTHOUGH BETTER RAIN CHANCES STAY OVER LAKE MICHIGAN. HIGH  
PRESSURE THEN BUILDS BACK INTO ONTARIO EARLY NEXT WEEK, COMPLEMENTED  
BY RIDGING ALOFT, TO CONTINUE THE STRETCH OF FAVORABLE MARINE  
WEATHER.  
 
 
   
PREV DISCUSSION  
 
ISSUED AT 1157 PM EDT WED SEP 10 2025  
 
AVIATION...  
 
MIXED COVERAGE OF HIGH CLOUDS DRIFT THROUGH THE UPPER AIR PATTERN  
ABOVE DIFFUSE SURFACE PRESSURE ACROSS THE GREAT LAKES. VFR IS  
MAINTAINED IN AN OTHERWISE DRY BOUNDARY LAYER OVER THE REGION. LIGHT  
AND VARIABLE TO CALM WIND BECOMES NE AT 10 KNOTS OR LESS AS LARGER  
SCALE HIGH PRESSURE BUILDS FROM NORTHERN ONTARIO INTO QUEBEC DURING  
THE DAY INTO THURSDAY EVENING.  
 
FOR DTW/D21 CONVECTION... NO THUNDERSTORMS DURING THE LATE WEEK  
PERIOD.  
 
THRESHOLD PROBABILITIES...  
 
* NONE.  
 
 
   
DTX WATCHES/WARNINGS/ADVISORIES  
 
MI...NONE.  
LAKE HURON...NONE.  
LAKE ST CLAIR...NONE.  
MICHIGAN WATERS OF LAKE ERIE...NONE.  
 
 
 
 
DISCUSSION...SF  
MARINE.......MV  
AVIATION.....BT  
 
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