421  
FXUS63 KDTX 111002  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
602 AM EDT MON AUG 11 2025  
   
KEY MESSAGES
 
 
- WARM AND MUGGY CONDITIONS CONTINUE TODAY THROUGH TUESDAY WITH  
HIGHS IN THE LOW 90S AND HEATING INDICES IN THE MID-90S.  
 
- POTENTIAL FOR SHOWERS AND NON-SEVERE THUNDERSTORMS FROM MID  
AFTERNOON INTO THE EVENING HOURS TODAY.  
 
- SHOWERS AND THUNDERSTORMS AGAIN POSSIBLE TUESDAY, WITH THE  
POTENTIAL FOR HEAVY RAINFALL.  
 
- HIGH PRESSURE BRINGS LESS HUMID CONDITIONS FOR THE LATTER HALF OF  
THE WEEK.  
 

 
   
AVIATION
 
 
PREDOMINATELY VFR CONDITIONS TODAY WITH THE POSSIBLE EXCEPTION OF  
LATER THIS AFTERNOON/EVENING WHEN A ROUND OF SHOWERS AND  
THUNDERSTORMS IS EXPECTED TO DEVELOP AND DRIFT EAST MAINLY BETWEEN  
20-00Z. SHOULD HAVE A QUIET PERIOD UNTIL LATER OVERNIGHT WHEN THE  
LOW LEVEL JET FLARES UP AHEAD OF THE COLD FRONT IN THE MOISTURE RICH  
AIR. COULD SEE A CLUSTER OF STORMS WORK NORTHEAST THROUGH THE REGION  
AROUND 09-12Z FOR A FEW HOURS. BOTH PERIODS OFFER BETTER CHANCES FOR  
MBS/FNT/PTK BUT A CHANCE FARTHER SOUTH TO DETROIT AS WELL. BEING  
TOWARD THE END OF THE TAF PERIOD FOR MOST, HELD OFF ON INTRODUCING  
PROB30 FOR THE MORNING ACTIVITY. WINDS WILL BE OUT OF THE SOUTH-  
SOUTHWEST AROUND 10 KNOTS WITH SOME GUSTS INTO THE TEENS TODAY.  
 
FOR DTW/D21 CONVECTION... THERE IS A GREATER CHANCE OF THUNDERSTORMS  
TOWARD THE NORTHERN REACH OF D21, LOWER TOWARD DTW MID AFTERNOON  
INTO THIS EVENING. SECOND ROUND OF ACTIVITY POSSIBLE AROUND 09-12Z  
TONIGHT INTO TUESDAY MORNING.  
 
THRESHOLD PROBABILITIES...  
 
* LOW FOR THUNDERSTORMS AFTER 18Z MONDAY AFTERNOON.  
 

 
   
PREV DISCUSSION
 
 
ISSUED AT 352 AM EDT MON AUG 11 2025  
 
DISCUSSION...  
 
ENTRENCHED HIGHER MAGNITUDE WARMTH WITH ACCOMPANYING ELEVATED  
HUMIDITY WILL CONTINUE TO MARK CONDITIONS TO START THE WORK WEEK.  
GOVERNING HIGH AMPLITUDE RIDGING MAINTAINS CONTROL THROUGH AT LEAST  
THE FIRST HALF OF THE DAYLIGHT PERIOD TODAY, WITH DEEPER LAYER  
STABILITY HELD UNDER A WARM MID LEVEL PROFILE LACKING IN MEANINGFUL  
THERMAL/MOISTURE ADVECTION. THIS AFFORDS A SIMILAR OUTCOME IN  
PROJECTED HEAT INDEX, WITH AFTERNOON READINGS AGAIN PEAKING IN THE  
MIDDLE 90S. THE EJECTION OF A SURFACE LOW INTO THE NORTHERN GREAT  
LAKES WILL COMBINE WITH SUBTLE HEIGHT FALLS TO DRAW A PLUME OF  
HIGHER MID LEVEL THETA-E ATTENDANT TO A SURFACE TROUGH INTO THE  
REGION DURING PEAK HEATING. THE IMPROVEMENT IN 925-700 MB MOISTURE  
QUALITY AND SUBSEQUENT DESTABILIZATION BENEATH ANY LINGERING MID  
LEVEL CAPPING APPEARS SUFFICIENT TO SUPPORT SOME DEGREE OF  
CONVECTIVE DEVELOPMENT ALONG THE ADVANCING CONVERGENCE AXIS ANYTIME  
BETWEEN MID AFTERNOON AND THE EVENING HOURS. CONVECTIVE DEPTH MUTED  
BY PALTRY MID LEVEL LAPSE RATES, WHILE MEAGER 0-6 KM BULK SHEAR WILL  
KEEP ANY ACTIVITY DISORGANIZED. SLOW STORM MOTION WITHIN A HIGH PWAT  
ENVIRONMENT OFFERS LOCALIZED HEAVY RAINFALL POTENTIAL.  
 
SOUTHWEST FLOW OF GREATER DEPTH WILL EXIST TONIGHT AND TUESDAY. THIS  
MAINTAINS POTENTIAL FOR INTERVALS OF GREATER MOISTURE ADVECTION TO  
OCCUR AT TIMES, WITH A PARTICULAR FOCUS WITH NOCTURNAL LOW LEVEL JET  
DEVELOPMENT OVERNIGHT AND ANY LESS DEFINED CONVECTIVELY ENHANCED  
VORTICITY REMNANTS TRAVERSING THE MEAN FLOW. A VIRTUALLY IMPOSSIBLE  
ENVIRONMENT TO OFFER ANY CONFIDENCE IN TERMS OF TIMING, LOCATION AND  
COVERAGE OF CONVECTIVE DEVELOPMENT THIS PERIOD GIVEN THE ILL-DEFINED  
FORCING FIELD. PLAUSIBLE THE EXISTING ENVIRONMENT SIMPLY BECOMES  
SUPPORTIVE OF A MORE CHAOTIC FREE CONVECTIVE RELEASE ONCE DAYTIME  
HEATING FINDS AN ATTAINABLE MID 80S CONVECTIVE TEMPERATURE. FORECAST  
WILL CONTINUE TO HIGHLIGHT A SCATTERED TO NUMEROUS SHOWER/STORM  
MENTION, TARGETING THE TUE AFTERNOON AND EVENING WINDOW. EFFICIENT  
RATE RATE LIKELY WITH ANY ACTIVITY GIVEN THE MOISTURE QUALITY, AGAIN  
RAISING CONCERN FOR SOME POCKETS OF HEAVY RAINFALL.  
 
A MORE DYNAMIC MID LEVEL WAVE LIFTING ACROSS THE NORTHERN GREAT  
LAKES WILL SHIFT A COLD FRONT ACROSS THE REGION EARLY WEDNESDAY  
MORNING. SECONDARY SHORTER WINDOW FOR CONVECTIVE DEVELOPMENT GIVEN  
THE INCREASE IN LARGE SCALE FORCING THIS PERIOD, BUT OFFSET BY A  
NOTEWORTHY REDUCTION IN AVAILABLE INSTABILITY AT THIS STAGE,  
PARTICULARLY IF EARLIER ACTIVITY EFFECTIVELY STABILIZED THE PROFILE.  
TEMPERATURES THEN TRENDING MORE SEASONABLE WITH NOTABLY LESS  
HUMIDITY FOR THE LATE WEEK PERIOD AS CANADIAN HIGH PRESSURE TAKES  
CONTROL.  
 
MARINE...  
 
SOUTHWESTERLY WINDS PERSIST TODAY AND TUESDAY WITH A CORRIDOR OF LOW-  
END CONCERN FOR ISOLATED TO SCATTERED CONVECTIVE ACTIVITY, MAINLY  
FOR NORTHERN AND CENTRAL LAKE HURON. FAVORABLE MARINE CONDITIONS  
PERSIST FOR THE REST OF THE CENTRAL GREAT LAKES DUE TO HIGH PRESSURE  
ANCHORED OVER THE SOUTHEAST. A NORTHERN GREAT LAKES COLD FRONT WILL  
TAKE UNTIL MIDWEEK TO CLEAR THROUGH THE REGION WHICH EVENTUALLY  
OFFERS CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS ALL THE LOCAL  
WATERWAYS. THE FRONT SHOULD EXIT TUESDAY NIGHT, FOLLOWED BY A ZONAL  
WIND SHIFT INTO WEDNESDAY BEHIND BOUNDARY WHICH TRANSLATES TO DRIER  
CONDITIONS.  
 
HYDROLOGY...  
 
MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS  
AFTERNOON THROUGH TUESDAY AHEAD OF A COLD FRONT THAT TRACKS THROUGH  
THE AREA TUESDAY NIGHT. MOISTURE RICH CONDITIONS ARE CHARACTERIZED  
BY PWAT VALUES UP TO 2 INCHES AND DEWPOINTS IN THE LOW 70S.  
SCATTERED THUNDERSTORM ACTIVITY WILL BE CAPABLE OF PRODUCING HEAVY  
RAINFALL WITH RATES OVER AN INCH PER HOUR THIS AFTERNOON AND  
EVENING. THIS WILL BE FOLLOWED BY MULTIPLE POTENTIAL WAVES OF  
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY MORNING, IN WHICH SLOW-  
MOVING AND/OR TRAINING THUNDERSTORMS WILL BE POSSIBLE. FLASH  
FLOODING WILL BE POSSIBLE IN URBAN AND LOW-LYING AREAS ALONG WITH  
RISES IN AREAS RIVERS.  
 

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

 
 

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