131
FXUS63 KDTX 301907
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
307 PM EDT SUN AUG 30 2026
KEY MESSAGES
- PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE THROUGH
MUCH OF THE WEEK, WITH THE HIGHEST COVERAGE FAVORED ACROSS NORTHERN
AREAS.
- VERY WARM AND HUMID CONDITIONS ARE EXPECTED MONDAY THROUGH
WEDNESDAY, THOUGH DAILY PEAK TEMPERATURES WILL DEPEND ON CLOUD COVER
AND PRECIPITATION.
DISCUSSION
A MOIST AIRMASS IS IN PLACE OVER LOWER MICHIGAN, AS BOTH 12Z DTX/APX
RAOBS CAME IN WITH A 5 C DEW PT AT 700 MB. WAVES OF ISENTROPIC
ASCENT HAVE BEEN SUPPORTIVE OF WIDESPREAD SHOWERS. FORTUNATELY,
INSTABILITY IS LIMITED, AND RAINFALL AMOUNTS HAVE BEEN MANAGEABLE,
GENERALLY IN THE RANGE OF A QUARTER OF AN INCH (SOUTH) TO ONE INCH
(NORTH).
AN UPPER LEVEL RIDGE/HEAT DOME OVER THE CENTRAL PLAINS WILL DRIFT
NORTHEAST, REACHING SOUTHERN ILLINOIS BY MONDAY EVENING. THE
EXTENSION OF THE RIDGE AXIS OVER THE NORTHERN MISSISSIPPI RIVER
VALLEY WILL SUBSEQUENTLY MOVE OVERHEAD INTO THE CENTRAL GREAT LAKES
ON MONDAY AS WELL. HIGH TEMPERATURES WILL BE DEPENDENT ON HOW WELL
THE WARM FRONT AND TONIGHT'S EXPECTED SHOWERS AND THUNDERSTORMS
CLEAR SOUTHEAST MICHIGAN MONDAY MORNING. THE NORTH HALF OF THE CWA
IS FAVORED LOCATION, AS LOCAL PROBABILISTIC GUIDANCE SUGGESTS POPS
AOA 70 PERCENT NORTH OF M-46.
WITH 850 MB TEMPS PROGGED TO RISE INTO THE 20-21 C RANGE MONDAY-
WEDNESDAY, MAX TEMP POTENTIAL IS CERTAINLY AOA 90. HOWEVER, MUCH
LIKE TODAY, ANY THICK CLOUD COVER AND SHOWER/THUNDER ACTIVITY DURING
THE DAY COULD SHORT-CIRCUIT MAX TEMPS. IN ADDITION, THE OUTGOING NBM
SURFACE DEW PTS APPEAR TO BE TOO HIGH (WIDESPREAD LOWER 70S), SO
ADVERTISED HEAT INDICES APPEAR TOO HIGH AS WELL.
THE UPPER-LEVEL RIDGE IS ALREADY FLATTENED ON TUESDAY OVER LOWER
MICHIGAN, WITH WESTERLY FLOW IN PLACE AS 500 MB LOW TRACKS THROUGH
NORTHERN ONTARIO. AT LEAST MODERATE INSTABILITY BUILDING UP IN A
WEAKLY CAPPED ENVIRONMENT SUGGESTS THAT THERE WILL BE SOME DIURNAL
ACTIVITY, ESPECIALLY WITH ANY ENHANCED LOW LEVEL CONVERGENCE/LAKE
BREEZE/MARINE INFLUENCE. SUFFICIENT BULK SHEAR TO SUPPORT A CHANCE
OF SEVERE STORMS, IF IN FACT STORMS DO GO UP.
A SLIGHT DRYING OUT OF THE DEEPER MOISTURE IN PLACE AS WE HEAD INTO
WEDNESDAY COULD SUPPORT THE WARMEST MAXES OF THE WEEK, PER THE NBM.
STILL, CONFIDENCE IS NOT HIGH, AS HEIGHT FALLS ARRIVE BY WEDNESDAY
EVENING/NIGHT AND A POTENTIALLY ACTIVE BAROCLINIC/FRONTAL ZONE
DEVELOPS OVER SOUTHERN LOWER MICHIGAN INTO THURSDAY.
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 SOUTH TODAY WITH MAX GUSTS
AROUND 20 KNOTS. WINDS TURN MORE SOUTHEASTERLY ON MONDAY WHILE
REMAINING MOSTLY BELOW 20 KNOTS BEFORE TURNING WESTERLY ON TUESDAY.
HYDROLOGY
RENEWED SHOWER DEVELOPMENT AND POSSIBLE THUNDERSTORMS ARE EXPECTED
TONIGHT INTO MONDAY MORNING, MAINLY NORTH OF THE I-69 CORRIDOR. WITH
TODAY'S HEAVIEST RAINFALL FALLING ALONG M-46 PRIMING THE GROUND,
EVEN A LOW CHANCE SCENARIO OF RAINFALL TOTALS EXCEED 1 INCH LATE
TONIGHT INTO MONDAY MORNING COULD CAUSE LOCALIZED MINOR FLOODING OF
ROADS, POOR-DRAINAGE AREAS AND RISES IN LOCAL RIVERS. THE CHANCE FOR
ADDITIONAL SHOWERS AND THUNDERSTORMS LINGERS MONDAY INTO TUESDAY.
ANY ISOLATED TO SCATTERED STORMS ON TUESDAY COULD BECOME INTENSE AND
PRODUCE TORRENTIAL RAINFALL, LEADING TO LOCALIZED FLOODING IN POOR
DRAINAGE AREAS AS WELL.
PREV DISCUSSION
ISSUED AT 130 PM EDT SUN AUG 30 2026
AVIATION...
WIDESPREAD RAINFALL NOW PULLING EAST OF THE SOUTHEAST MICHIGAN
TERMINAL CORRIDOR. A SMALLER, MORE PERSISTENT REGION OF SHOWERS
CONTAINING EMBEDDED THUNDERSTORMS WILL CONTINUE TO FOCUS MAINLY JUST
TO THE NORTH OR IN THE VICINITY OF MBS OVER THE NEXT SEVERAL HOURS.
THIS ACTIVITY TIED TO AN ORGANIZING WARM FRONTAL BOUNDARY, WHICH
WILL STILL OFFER AT LEAST MODEST POTENTIAL FOR SOME RENEWED
SHOWER/ISOLATED THUNDERSTORM POTENTIAL THROUGH THIS EVENING. HIGHER
PROBABILITY AT MBS/FNT, BUT WITH CONFIDENCE IN FURTHER REDEVELOPMENT
REMAINS STILL QUITE LOW GIVEN THE LIMITED INSTABILITY. OTHERWISE,
PREVAILING VFR INTO THE EVENING WITHIN LINGERING POCKETS OF THICKER
MID CLOUD AT TIMES. POTENTIAL FOR SHOWER PRODUCTION ALONG AND NORTH
OF THE WARM FRONT WILL EXIST TONIGHT INTO MONDAY, AGAIN PRIMARILY
FOCUSING NEAR MBS.
D21/DTW CONVECTION...A VERY LOW POTENTIAL EXISTS FOR AN ISOLATED
THUNDERSTORM THROUGH THIS EVENING.
DTW THRESHOLD PROBABILITIES...
* LOW IN THUNDERSTORMS THROUGH THIS EVENING.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...SF
MARINE.......DRK
HYDROLOGY....SF
AVIATION.....MR
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