394
FXUS63 KDTX 311722
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
122 PM EDT MON AUG 31 2026
KEY MESSAGES
- PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE THROUGH
MUCH OF THE WEEK. TUESDAY CARRIES A MARGINAL RISK FOR SEVERE WEATHER
WITH WEDNESDAY EVENING CARRYING A MARGINAL TO SLIGHT RISK.
- WARM AND HUMID CONDITIONS DEVELOP THROUGH MID-WEEK. DAILY PEAK
TEMPERATURES WILL DEPEND ON CLOUD COVER AND PRECIPITATION.
AVIATION
ORGANIZED RAIN CHANCES WILL PERSIST INTO THE AFTERNOON WITH ELEVATED
WARM FRONT AND DEEP THETAE ADVECTION OCCURING OVER THE CENTRAL GREAT
LAKES. SUBSIDENCE IN THE WAKE WARM FRONT WILL LEAD TO CONVECTIVE
INHIBITION IN THE LOWEST 5.0 KFT AGL THIS EVENING AND TONIGHT. LOW
CONFIDENCE THEN MOVING FORWARD WITH LOWER PREDICTABILITY AS
INSTABILITY WILL PROVIDE A POSSIBILITY FOR CONVECTION AT ANY POINT IN
THE TAF FORECAST CYCLE. THERE IS A FEW HIRESOLUTION RUNS THAT
SUGGEST SOME ELEVATED THUNDERSTORM CHANCES FOR THE THE NORTHERN
FORECAST AREA INCLUDING MBS. WILL MAINTAIN A DRY FORECAST FOR THE
DETROIT TERMINALS AND MONITOR THE LATEST GUIDANCE. VFR CONDITIONS ARE
ANTICIPATED FOR THE PERIOD TONIGHT AND EARLY TUESDAY.
D21/DTW CONVECTION...THE PRESENCE OF INSTABILITY ALOFT TONIGHT WILL
SUPPORT A LOW CHANCE (<30 PERCENT) OF CONVECTION ACROSS THE AIRSPACE
THROUGHOUT THE TAF PERIOD. LOW CONFIDENCE IN OCCURRENCE AND/OR
TIMING.
DTW THRESHOLD PROBABILITIES
* LOW IN THUNDERSTORMS THIS AFTERNOON, TONIGHT AND EARLY TUESDAY.
PREV DISCUSSION
ISSUED AT 946 AM EDT MON AUG 31 2026
UPDATE...
LIKE YESTERDAY MORNING, HAVE INCREASED POPS AS TROPICAL MOISTURE
(12Z DTX SOUNDING INDICATING 7 C DEW PT AT 700 MB) HAS SUPPORTED A
THICK CANOPY OF CLOUDS ONCE AGAIN WITH HEALTHY COVERAGE OF HIGH
BASED SHOWERS AS A SHORTWAVE TRACKS THROUGH LOWER MICHIGAN.
INSTABILITY CONTINUES TO BE MEAGER, PREVENTING FLOODING RAINFALL AND
LIMITING COVERAGE OF THUNDERSTORMS. MADE NO ADJUSTMENTS TO MAXES, AS
FORECAST IS LOWER THAN MAV/MET/ECS GUIDANCE AND CERTAINLY THE RIGHT
DIRECTION WITH EXTENSIVE CLOUD COVER TAKING MUCH OF THE DAY TO THIN
OUT.
PREV DISCUSSION...
ISSUED AT 400 AM EDT MON AUG 31 2026
DISCUSSION...
AN UNSETTLED/ACTIVE WEATHER PATTERN IS EXPECTED TO SET UP OVER
SOUTHEAST MICHIGAN THROUGH THIS WEEK AS WE RESIDE ON THE NORTH END
OF A FLATTENED MID/UPPER LEVEL RIDGE. THE CENTER OF THIS RIDGE WILL
BE SLOW MOVING ACROSS THE MID MISSISSIPPI RIVER VALLEY AND OVER THE
OH/TN RIVER VALLEYS OVER THE NEXT SEVERAL DAYS. QUASI-ZONAL MID-
LEVEL FLOW AND SOUTHWESTERLY LOW LEVEL FLOW WILL ALLOW FOR A
PERSISTENT WARM AND MOIST AIRMASS ACROSS THE REGION. THIS WILL HELP
SUPPORT NEAR DAILY SHOWER AND THUNDERSTORM CHANCES THROUGHOUT MOST OF
THE WEEK AS SHORTWAVES WAVES AND FRONTAL/BAROCLINIC ZONES CAPITALIZE
ON THE FAVORABLE WARM AND HUMID ENVIRONMENT.
FOR TODAY, A WARM FRONT WILL BE THE FOCUS FOR SCATTERED SHOWERS THIS
MORNING INTO THE AFTERNOON. THERE WILL BE A DECREASING PRECIPITATION
TREND WITH TIME TODAY AS THE FRONT IS DRAWN NORTHWARD BY THE
PROGRESSION OF THE MIDWEST LOW PRESSURE SYSTEM. LOW LEVEL JET
FORCING OVER THE FRONT WILL KICK OFF THE HIGHEST COVERAGE OF CHANCE
POPS THIS MORNING THROUGH 18Z THIS AFTERNOON. NOT EXPECTING A SEVERE
THUNDERSTORM THREAT AS INSTABILITY WILL BE LIMITED WITH POOR CAPE
DEPTH AND MUCAPE VALUES OF LESS THAN 500 J/KG. THE THREAT OF HEAVY
RAINFALL HAS DECREASED TO SOME DEGREE WITH THIS ADDITIONAL ROUND OF
PRECIPITATION ACROSS THE THUMB, ESPECIALLY WITH THE BREAK IN
PRECIPITATION LAST EVENING. QPF THROUGH 18Z THIS AFTERNOON OFFERS
0.25-0.50" OF RAINFALL WITH SOME MODEL SUPPORT FOR UP TO AN INCH
POSSIBLE ACROSS THE PORTIONS OF THE THUMB. WARMER AIRMASS PUSHING
INTO SOUTHEAST MICHIGAN TODAY WITH 850 MB TEMPERATURES TOWARDS 20C
WILL SUPPORT HIGHS TOWARDS THE MID 80S IF ENOUGH CLEARING CAN OCCUR
POST MORNING ACTIVITY.
BETTER INSTABILITY WILL BUILD ACROSS THE AREA ON TUESDAY WITH A WEAK
CAP PRESENT. HREF HIGHLIGHTS MEAN SURFACE CAPE VALUES INCREASING TO
2000+ J/KG DURING THE AFTERNOON. STEEPER MID-LEVEL LAPSE TO AROUND 7C
AND 0-6KM BULK SHEAR VALUES OF 30-45 KNOTS WILL BE MORE THAN
SUPPORTIVE OF MORE ORGANIZED CONVECTION IF ANY ACTIVITY IS ABLE TO
DEVELOP. HI- RES MODELS SHOWING A BIT OF VARIETY IN BOTH TIMING AND
OVERALL CONVECTIVE RESPONSE, SO TUESDAY STILL CARRIES A DEGREE OF
UNCERTAINTY WITH THE BETTER FORCING MECHANISM ILL-TIMED WITH THE
BETTER DIURNAL INSTABILITY. GIVEN THE FAVORABLE ENVIRONMENT, ANY
STORM THAT CAN DEVELOP SHOULD BE ABLE TO MATURE AND BE CAPABLE OF A
SEVERE WIND AND HAIL THREAT ALONG WITH HEAVY DOWNPOURS. SPC HAS
MAINTAINED A MARGINAL RISK FOR SEVERE WEATHER ACROSS ALL OF SOUTHEAST
MICHIGAN GIVEN THE FAVORABLE ENVIRONMENT.
WEDNESDAY LOOKS LIKE THE BEST CHANCE TO BE THE WARMEST DAY OF THE
WEEK IF THE HIGHER COVERAGE OF CLOUDS AND PRECIPITATION HOLD FURTHER
TO THE NORTH. THIS COULD PUSH TEMPERATURES IN THE AFTERNOON TO AROUND
90 DEGREES. AS WITH MOST OF THE DAYS THIS WEEK, ANY HIGHER COVERAGE
OF PRECIPITATION AND CLOUDS WILL TEMPER NBM FORECAST HIGHS. COLD
FRONT AND HEIGHT FALLS FORECAST TO ARRIVE LATE WEDNESDAY
AFTERNOON INTO THURSDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS
AND THUNDERSTORMS. FAVORABLE ENVIRONMENT FOR STRONG TO SEVERE
THUNDERSTORMS WILL AGAIN BE IN PLACE WITH MLCAPE VALUES TO 2000+
J/KG, STEEP MID-LEVEL LAPSE RATES, AND FAVORABLE SHEAR THAT WILL
POSE A WIND AND HAIL RISK.
MARINE...
SEVERAL DAYS OF UNSETTLED WEATHER AS A PRIMARY LOW PRESSURE SYSTEM
OVER CENTRAL CANADA AND SECONDARY LOW OVER THE NORTHERN PLAINS SEND
A SERIES OF FRONTS ACROSS THE REGION. PERIODIC SHOWERS AND
THUNDERSTORMS WILL ACCOMPANY THE FRONTS WHILE THE SLIGHTLY COOLER AIR
OVER THE WATERS BRINGS CHANCES OF WATERSPOUTS WITH THE STORMS OVER
THE LAKES. WINDS WILL LARGELY BE FROM THE SOUTHEAST TODAY WITH MAX
GUSTS UP TO 20 KNOTS. WINDS TURN BRIEFLY WESTERLY ON TUESDAY BEFORE
TURNING BACK TO THE SOUTHWEST ON TUESDAY NIGHT.
HYDROLOGY...
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS THIS MORNING TO THE EARLY
AFTERNOON MAINLY NORTH OF THE I-69 CORRIDOR, PARTICULARLY ACROSS THE
THUMB. AVERAGE RAINFALL TOTALS ARE IN THE 0.25" TO 0.50" RANGE WITH
LOCALIZED AREAS UP TO 1 INCH POSSIBLE THIS MORNING UNTIL EARLY
AFTERNOON. FLOODING THREAT HAS DECREASED COMPARED TO YESTERDAY, BUT
LOCALIZED MINOR FLOODING OF ROADS AND POOR-DRAINAGE AREAS WILL BE
POSSIBLE IF REPEATED ROUNDS OF HEAVIER DOWNPOURS OCCURS. ISOLATED TO
SCATTERED SEVERE THUNDERSTORMS WILL BE POSSIBLE ON TUESDAY AND WILL
COME WITH A HEAVY RAINFALL THREAT IF ANY ORGANIZED STORMS ARE ABLE
TO DEVELOP.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....CB
UPDATE.......SF
DISCUSSION...AA
MARINE.......DRK
HYDROLOGY....AA
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AT WWW.WEATHER.GOV/DETROIT.
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