416
FXUS63 KDTX 031113
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
713 AM EDT THU SEP 3 2026
KEY MESSAGES
- WARM AND HUMID AGAIN TODAY WITH HEAT INDICES IN THE 90S, THE
WARMEST OF WHICH WILL BE FOUND CLOSER TO THE MI/OH BORDER AND INTO
THE METRO REGION.
- THERE IS A MARGINAL TO SLIGHT RISK FOR SEVERE WEATHER TODAY.
SEVERE WEATHER DEVELOPMENT WILL BE POSSIBLE AT ALL TIMES TODAY, BUT
MOST FAVORABLE TIMING WILL BE THIS AFTERNOON INTO LATE TONIGHT.
- SHOWER AND THUNDERSTORM CHANCES CONTINUE INTO TOMORROW.
AVIATION
HUMID CONDITIONS REMAIN THIS MORNING BEHIND THE FRONTAL BOUNDARY
DRAPED ACROSS LOWER MICHIGAN. THIS IS ALLOWING PATCHY DENSE FOG TO
DEVELOP. GREATEST COVERAGE IS NEAR MBS THIS MORNING AND HANGING JUST
NORTH OF FNT. A LULL IN SHOWERS AND THUNDERSTORMS WILL TRANSITION TO
RENEWED DEVELOPMENT OF SHOWERS THUNDERSTORMS UPSTREAM THAT ARE
EXPECTED MOVE INTO SOUTHEAST MICHIGAN BY THIS AFTERNOON. A PERIOD OF
PREDOMINATELY VFR CONDITIONS SHOULD PRECEDE THAT ARRIVAL. A
SECONDARY OPPORTUNITY FOR SHOWERS AND THUNDERSTORMS WILL POSSIBLE
TONIGHT AS PROBABILITY FOR LOWER MVFR CEILINGS ALSO INCREASES INTO
TOMORROW MORNING.
D21/DTW CONVECTION... MULTIPLE OPPORTUNITIES FOR SHOWERS AND
THUNDERSTORMS THROUGHOUT TODAY WITH FAVORED TIMING THIS AFTERNOON
INTO TONIGHT.
DTW THRESHOLD PROBABILITIES
* LOW FOR CEILING 5000 FT OR LESS EARLY THIS MORNING AND THIS
AFTERNOON. MODERATE AFTER 00Z TONIGHT.
* MODERATE FOR THUNDERSTORMS THIS AFTERNOON INTO LATE TONIGHT.
PREV DISCUSSION
ISSUED AT 345 AM EDT THU SEP 3 2026
DISCUSSION...
FOR THIS MORNING... SPC MESOANALYSIS CONTINUES TO SHOWCASE MUCAPE
VALUES AROUND 2000 J/KG ALONG WITH 35-40 KNOTS OF EFFECTIVE BULK
SHEAR WITH SUFFICIENT MID-LEVEL LAPSE RATES AROUND 5.5-6C/KM. THESE
CONDITIONS HAVE SUPPORTED REPEATED ROUNDS OF THUNDERSTORMS, SOME
STRONG TO SEVERE, PRIMARILY ALONG AND AND BETWEEN M59 TO I94.
INITIATION HAS TAKEN PLACE ALONG A QUASI-STATIONARY FRONTAL ZONE
WHICH HAS BEEN REINFORCED FROM PRIOR CONVECTIVE OUTFLOW. ADDITIONAL
SHOWERS AND STORMS REMAIN POSSIBLE THROUGH THIS MORNING AS THIS
BOUNDARY PROVIDES A MECHANISM FOR ASCENT WITHIN THIS SUBTROPICAL
AIRMASS. GIVEN THE DEGREE OF ELEVATED INSTABILITY AND BULK SHEAR,
ISOLATED STRONG TO SEVERE THUNDERSTORMS CANNOT BE RULED OUT THROUGH
THE MORNING.
WARM AND HUMID CONDITIONS ARE AGAIN EXPECTED THIS AFTERNOON
DEWPOINTS AGAIN HOLDING IN THE UPPER 60S TO LOW 70S. CURRENT
THINKING IS THAT TEMPERATURES WILL BE SLIGHTLY LOWER RELATIVE TO
YESTERDAY WHICH DECREASES PROBABILITIES TO REACH HEAT ADVISORY
THRESHOLDS. ADDITIONALLY, GIVEN WHERE THE FRONTAL BOUNDARY IS, SOME
POTENTIAL EXISTS FOR SHOWERS AND THUNDERSTORMS THROUGH THE LATE
MORNING AND INTO THE AFTERNOON WHICH IF MATERIALIZED, COULD TEMPER
TEMPERATURES LOCALLY. ALTHOUGH SEVERAL HI-RES SOLUTIONS CONTINUE TO
RETAIN AN EARLY DAY PERIOD OF CLEARING AND STRONGER INSOLATION.
REGARDLESS, TEMPERATURES WILL BE CAPABLE OF PUSHING BACK INTO THE
UPPER 80S TO LOW 90S THROUGH THE MI/OH BORDER INTO THE METRO REGION
WITH HEAT INDICES IN THE MID TO UPPER 90S.
FOR THIS AFTERNOON AND EVENING, SE MI WILL BE SUSCEPTIBLE TO RENEWED
THUNDERSTORM ACTIVITY. ONE POSSIBLE SCENARIO WILL STREAM FROM
ACTIVITY UPSTREAM ACROSS WISCONSIN OR THE WESTERN GREAT LAKES AS A
STRENGTHENING LLJ POOLS MOISTURE AND ENHANCES CONVERGENCE ALONG THE
STALLED FRONTAL ZONE. MEAN FLOW AND FORECASTED STORM MOTION WOULD
CARRY THIS ACTIVITY SE TOWARDS LOWER MICHIGAN THROUGH THE AFTERNOON
AND EVENING, PLACING ALL OF SE MI WITHIN THE CORRIDOR FOR POTENTIAL
STRONG TO SEVERE THUNDERSTORM DEVELOPMENT. SURFACE BASED INSTABILITY
WILL INCREASE WITH SOUTHWARD EXTEND. SBCAPE AROUND 1500-2000 J/KG IS
POSSIBLE NEAR THE MI/OH BORDER AND TAPERS TOWARDS 1000 J/KG NORTH OF
I-69. DEEP LAYER SHEAR AROUND 30-35 KNOTS REMAINS SOLID FOR
ORGANIZED CONVECTION WITH ALL STORM MODES POSSIBLE.
DAMAGING WIND GUSTS WILL REMAIN THE PRIMARY HAZARD WHEN TAKING INTO
ACCOUNT STRONG LOW-LEVEL LAPSE RATES, HIGH PW, AND STRONG BUOYANCY.
THIS WILL SUPPORT EFFICIENT PRECIPITATION LOADING FOR WET
MICROBURSTS AND/OR CONSOLIDATION OF OUTFLOWS WITH COLD POOL DYNAMICS
THAT CAN SUPPORT BOWING SEGMENTS. ISOLATE LARGE HAIL ALSO REMAINS
POSSIBLE GIVEN IMPROVING MID-LEVEL LAPSE RATES APPROACHING 6.5C/KM.
A LARGE PORTION OF SE MI HAS BEEN UPGRADED TO A SLIGHT RISK IN THE
LATEST SWODY 1, ALIGNED WHERE THE BETTER DAYTIME INSTABILITY IS
PROJECTED TO RESIDE.
ADDITIONAL ROUNDS OF SHOWERS AND STORMS THEN BECOMES INCREASINGLY
LIKELY LATE TONIGHT INTO FRIDAY MORNING AS AN ELEVATED WARM FRONT
STRENGTHENS FROM SE WI INTO LOWER MICHIGAN. THIS HAS BEEN A PRETTY
ROBUST SIGNAL IN THE LATEST 00Z RUNS. THE BOOST IN LOW TO MID-LEVEL
THETA A WITH CONVERGENCE ALONG THIS BOUNDARY WILL HELP SUPPORT AN
AREA OF SHOWERS AND STORMS OVERNIGHT. WHILE SURFACE BASE INSTABILITY
DIMINISHES DURING THIS TIME, ELEVATED INSTABILITY AND STRONG SHEAR
HOLDS WHICH WILL MAINTAIN POTENTIAL FOR ORGANIZED CONVECTION. STORM
THREAT WOULD TRANSITION TO HAIL GIVEN THE MORE ELEVATED NATURE OF
THIS ACTIVITY ALONG WITH LOCALIZED HEAVY RAINFALL AND FLOODING,
ESPECIALLY WITH ANY REPEATED CONVECTION ALONG THE BOUNDARY. SOME
UNCERTAINTY RESIDES HOW FAR EAST THIS ACTIVITY WILL EXTEND, BUT THE
TRENDS STILL TAKE ACTIVITY TO OR SOUTH OF M59 OVERNIGHT.
FRIDAY WILL AGAIN OFFER ADDITIONAL CHANCES FOR RAIN AND THUNDERSTORM
BEFORE RIDGE AMPLIFICATION ACROSS THE PLAINS AIDS IN REINFORCING
HIGH PRESSURE OVER THE GREAT LAKES, WHICH WILL WORK TO DECREASE RAIN
AND THUNDERSTORM CHANCES THIS WEEKEND.
MARINE...
WINDS AND WAVES REMAIN BELOW THRESHOLD CRITERIA ACROSS THE CENTRAL
GREAT LAKES, ASIDE FROM A FEW THUNDERSTORMS PASSING THROUGH A VERY
MUGGY AIR MASS THIS AFTERNOON AND EVENING. GRADIENT WINDS WILL SHIFT
FROM SOUTHWEST TO NORTHWEST ONCE A WEAK COLD FRONT DROPS
SOUTHEASTWARD THROUGH REGION. CONVECTIVE CHANCES DECREASE A BIT
OVERNIGHT WITHIN THE WAKE OF THE SLOWING FRONT, AND WINDS COULD
BRIEFLY TREND TOWARDS CALM. A LOW CONFIDENCE FORECAST PERSIST
THROUGH THE END OF THE WEEK AND EARLY THIS WEEKEND AS A RIDGE OVER
CENTRAL CONUS REMAINS QUASI-STATIONARY. THIS OFFERS SEVERAL
ADDITIONAL OPPORTUNITIES FOR PERIODS OF SHOWERS AND THUNDERSTORMS.
MWS AND SMW HEADLINES WILL CONTINUED TO BE USED TO ADDRESS SHORT-
TERM LOCAL WATERCRAFT CONCERNS. NO LONG-FUSED HEADLINE CONCERNS
THROUGH THE WEEKEND, ALTHOUGH AREAS OF DENSE FOG COULD BECOME AN
ISSUE AGAIN LATE TONIGHT INTO THURSDAY MORNING FOR PORTIONS OF THE
WATERWAYS.
HYDROLOGY...
THERE WILL BE MULTIPLE CHANCES FOR THUNDERSTORM DEVELOPMENT THROUGH
THE ENTIRETY OF THE DAY TODAY, WITH THE AFTERNOON AND EVENING HOURS
AFFORDING THE BEST TIME FRAME FOR SOME BETTER COVERAGE. GIVEN THAT
SE MI REMAINS IN A SUBTROPICAL AIR MASS, PRECIPITATION RATES WILL BE
VERY EFFICIENT WITH ANY THUNDERSTORMS. A QUICK 1-2" OF RAINFALL WILL
BE POSSIBLE WITH ANY STRONGER THUNDERSTORMS WHICH WOULD LEAD TO
LOCALIZED FLOODING CONCERNS. OVERNIGHT, THERE IS A SIGNAL FOR
SHOWERS OR THUNDERSTORM DEVELOPMENT TO THEN SET UP AROUND OR SOUTH
OF M59, WHICH WILL BE CAPABLE OF PRODUCING AN ADDITIONAL 1-2+" OF
RAINFALL PENDING WHERE THIS RAINFALL AXIS SETS UP.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....AA
DISCUSSION...AM
MARINE.......KGK
HYDROLOGY....AM
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page