321  
FXUS63 KDTX 160931  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
531 AM EDT TUE SEP 16 2025  
   
KEY MESSAGES
 
 
- ABOVE NORMAL HIGH TEMPERATURES CONTINUE INTO THE WEEKEND.  
 
- DRY WEATHER THROUGH THE FIRST HALF OF THE WEEKEND.  
 

 
   
AVIATION
 
 
PATTERN REMAINS THE SAME AS PRIOR FEW NIGHTS WITH HIGH PRESSURE IN  
PLACE ACROSS THE GREAT LAKES. FOG THIS MORNING, LIKE YESTERDAY, HAS  
STAYED ONLY PATCHY OVER THE BULK OF THE REGION WITH DENSER FOG  
(LIFR) CONFINED JUST NORTH OF MBS. THIS FOG LIKELY CREEPS SOUTH  
IMPACTING MBS THROUGH THE START OF THE NEW FORECAST PERIOD.  
LINGERING AREAS OF FOG DISSIPATE BY MID-MORNING AS SCT VFR DIURNAL  
CU AGAIN DEVELOPS FOR THE AFTERNOON.  
 
FOR DTW/D21 CONVECTION... NO THUNDERSTORMS THROUGH THE EARLY WEEK  
PERIOD.  
 
THRESHOLD PROBABILITIES...  
 
* NONE.  
 

 
   
PREV DISCUSSION
 
 
ISSUED AT 334 AM EDT TUE SEP 16 2025  
 
DISCUSSION...  
 
590 DM UPPER LEVEL HIGH FIXATED OVERHEAD EARLY THIS MORNING  
MAINTAINS FULL CONTROL HEADING INTO THE MID-WEEK PERIOD. THIS  
STAGNANT PATTERN LENDS TO VIRTUALLY NO CHANGE IN SENSIBLE WEATHER  
CONDITIONS THROUGH THURSDAY. ELEVATED HEIGHT FIELD CONTRIBUTING TO  
THIS STRETCH OF HIGHER MAGNITUDE WARMTH WILL KEEP PROJECTED HIGH  
TEMPERATURES GENERALLY WITHIN THE LOW TO MID 80S. MODEST DAILY  
MODERATION OF THE UNDERLYING THERMAL PROFILE WILL LEND TO THE  
WARMEST CONDITIONS ARRIVING THURSDAY WITH SOME UPPER 80S PLAUSIBLE.  
SURFACE HIGH PRESSURE ANCHORED TO THE NORTH AND EAST FAVORS  
CONTINUED LIGHT LOW LEVEL EAST/NORTHEAST FLOW. THIS TRAJECTORY WILL  
CONTINUE TO DRAW MARINE BOUNDARY LAYER MOISTURE INLAND DURING THE  
OVERNIGHT HOURS, FAVORING SOME DEGREE OF FOG FORMATION. HIGHER  
PROBABILITY FOR BOTH GREATER COVERAGE AND DENSITY WILL TEND RESIDE  
WITHIN A CLOSER PROXIMITY TO LAKE HURON AND SAGINAW BAY.  
 
NORTHERN STREAM SHORTWAVE GLANCING ACROSS THE NORTHERN GREAT LAKES  
WILL EASE A BACKDOOR COLD FRONT SOUTHWARD INTO CENTRAL LOWER MI  
THURSDAY EVENING AND OVERNIGHT. THIS FRONTAL ZONE WILL LINGER INTO  
FRIDAY, ESTABLISHING A GREATER SOUTH TO NORTH THERMAL GRADIENT AS  
COOLER NORTHEAST TO EAST FLOW ENGAGES THE MARINE ENVIRONMENT TO KEEP  
THE THUMB NOTABLY COOLER. A BRIEF UPTICK IN FRONTAL CONVERGENCE WITH  
A NARROW PLUME OF HIGHER THETA-E PRESENT COULD OFFER AN ISOLATED  
OPPORTUNITY FOR SHOWER DEVELOPMENT AS THE BOUNDARY SAGS INTO THE  
REGION. OTHERWISE DRY CONDITIONS HOLD TO FINISH THE WEEK. THIS  
BOUNDARY WASHES OUT AS LOW-MID LEVEL RIDGING AGAIN GOVERNS CONDITIONS  
HEADING INTO THE FIRST HALF OF THE WEEKEND. TEMPERATURES STILL EDGED  
ON THE WARMER SIDE OF AVERAGE, BUT MUTED SLIGHTLY RELATIVE TO THE  
WARMTH NOTED THIS WEEK AS EASTERLY FLOW CARRIES GREATER INFLUENCE AND  
CLOUD COVER MAY PROVE MORE PROBLEMATIC AS HIGH LEVEL MOISTURE  
INCREASES DOWNSTREAM OF AN INBOUND MID LEVEL WAVE. INTRODUCTORY  
PRECIP CHANCES CREEP BACK INTO THE FORECAST BY THE END OF THE WEEKEND  
AND EARLY NEXT WEEK AS GREATER MID LEVEL PV INTRUDES.  
 
MARINE...  
 
A RIDGE OF HIGH PRESSURE CONTINUES TO BRING AN EXTENDED PERIOD OF  
DRY WEATHER AND LIGHTER WINDS TO THE GREAT LAKES THROUGH THE WEEK.  
WINDS CONTINUE TO FAVOR A LIGHT EASTERLY COMPONENT, WITH SOME  
GRADUAL BACKING TO THE SOUTH EXPECTED BY TOMORROW. A SECONDARY HIGH  
PRESSURE SYSTEM IS EXPECTED TO DROP FROM THE CENTRAL CANADIAN  
PROVINCES INTO ONTARIO AND QUEBEC LATE THIS WEEK, WHICH WILL  
STRENGTHEN THE PRESSURE GRADIENT OVER THE GREAT LAKES REGION. THIS  
WILL AGAIN REINFORCE NORTHEASTERLY FLOW AND WILL BRING SOME ELEVATED  
WIND SPEEDS FOR LAKE HURON WHERE SUSTAINED WINDS NEARING 20 KNOTS  
AND GUST POTENTIAL TO 25 KNOTS WILL BE POSSIBLE.  
 

 
   
DTX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LAKE HURON...NONE.  
LAKE ST CLAIR...NONE.  
MICHIGAN WATERS OF LAKE ERIE...NONE.  

 
 

 
 
AVIATION.....KDK  
DISCUSSION...MR  
MARINE.......MR  
 
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE  
AT WWW.WEATHER.GOV/DETROIT.  
 
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