085
FXUS63 KDTX 311921
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
321 PM EDT MON AUG 31 2026
KEY MESSAGES
- VERY WARM OR HOT AND HUMID CONDITIONS DEVELOP TUESDAY AND
WEDNESDAY, THOUGH CLOUD COVER AND STORM POTENTIAL INTRODUCE
UNCERTAINTY INTO PEAK DAILY TEMPERATURES AND HEAT INDICES.
- PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE THROUGH
MUCH OF THE WEEK. TUESDAY CARRIES A MARGINAL RISK FOR SEVERE
WEATHER, WITH WEDNESDAY CARRYING A MARGINAL TO SLIGHT RISK.
DISCUSSION
SOUTHEAST MICHIGAN WILL REMAIN ON THE OUTER FRINGE OF A STRONG UPPER
LEVEL RIDGE (~597 DAM AT 500M MB) CENTERED OVER KENTUCKY/TENNESSEE
TUESDAY-WEDNESDAY. THIS PRESENTS A CHALLENGING TEMPERATURE FORECAST
AS CLOUDS AND CONVECTION COULD IMPACT THE MAXES, AS THEY HAVE DONE
THE PAST COUPLE OF DAYS. HIGH-RES MODELS ARE CONTINUING TO STRUGGLE
WITH THE EXTENT OF SHOWERS AND THUNDERSTORMS, AND PREFERENCE WAS TO
INCLUDE A LOW CHANCE OF SHOWERS AND THUNDERSTORMS TONIGHT AND
TOMORROW. A SHORTWAVE IS TRACKING THROUGH THE MIDWEST THIS AFTERNOON
AND WILL ROUND THE WEAK RIDGE AXIS IN PLACE ACROSS WESTERN/CENTRAL
GREAT LAKES TONIGHT. THERE IS A GOOD 850-700 MB THETA-E RIDGE/DEEP
MOISTURE AXIS STRADDLING THE SOUTHERN MICHIGAN BORDER, AND WITH
ANOTHER SUBTLE MOISTURE SURGE LATE TONIGHT ALONG AND SOUTH OF I-94
CORRIDOR. AT THE VERY LEAST, WOULD EXPECT SOME CONVECTIVE DEBRIS
LINGERING THROUGH THE MORNING HOURS, WHICH RAISES CONCERN THE MAX
TEMPS MAKE NOT MAKE IT INTO THE LOWER 90S AND WILL END UP CLOSER TO
90 DEGREES. THUS, CONFIDENCE WAS NOT HIGH ENOUGH TO ISSUE A HEAT A
ADVISORY FOR THE POSSIBLE HEAT INDICES OF 95-100 DEGREES. SOME DRYING
AND WARMING IN THE MID LEVELS IS EXPECTED TOMORROW AFTERNOON, WHICH
SHOULD SERVE AS SOME SEMBLANCE OF A CAP, THOUGH IT IS STILL NOT
TOTALLY CLEAR IF IT WILL HOLD COMPLETELY. IF A REMNANT BOUNDARY OR
LAKE BREEZE IS ABLE TO GET SOMETHING GOING, ISOLATED SEVERE STORMS
ARE POSSIBLE WITH MLCAPE OF 2000+ J/KG ADVERTISED AND FAVORABLE 0-6
KM BULK SHEAR OF 40+ KNOTS. BOTH SEVERE WIND AND HAIL POSSIBLE WITH
THE HIGH DEGREE OF INSTABILITY AND UPDRAFT STRENGTH.
MEANWHILE, A SEASONABLY STRONG UPPER LEVEL LOW IS TRACKING THROUGH
CENTRAL CANADA AND WILL SLOWLY FILL AS IT TRACKS THROUGH NORTHWEST
ONTARIO LATE TOMORROW. UNCERTAINTY REMAINS ON HOW WELL IT WILL DRIVE
A SURFACE FRONTAL BOUNDARY MEANDERING OVER THE GREAT LAKES REGION
SOUTH. UPPER LEVEL DISTURBANCE(S) COMING OUT OF THE FOUR CORNERS
REGION LOOK TO ARRIVE INTO THE WESTERN/CENTRAL GREAT LAKES TUESDAY
NIGHT AND ESPECIALLY WEDNESDAY. EXACT TIMING WILL BE IMPORTANT FOR
SEVERE CHANCES, AND SPC DAY 3 OUTLOOK CONTINUES TO HIGHLIGHT A
SLIGHT RISK FOR SEVERE STORMS. BULK SHEAR WILL BE VERY HIGH, AND
THERE IS A LEGIT CHANCE FOR CONVECTION TO DEVELOP TUESDAY NIGHT INTO
WEDNESDAY MORNING, ONCE AGAIN IMPACTING MAXES AND SEVERE CHANCES.
THERE STILL IS NOT ENOUGH OF A SOUTHWARD PUSH TO THE FRONT FOR
THURSDAY, SO A RENEWED ROUND OF SHOWERS AND THUNDERSTORMS REMAINS
POSSIBLE AS THE RIDGE AXIS BUILDS BACK OVER THE MISSISSIPPI RIVER
VALLEY TO END THE WORKWEEK.
MARINE
LOW PRESSURE SYSTEM OVER SOUTHERN MANITOBA HAS AN OCCLUDED FRONT
REACHING DOWN INTO NORTHERN MINNESOTA WITH A WARM FRONT THEN
EXTENDING EAST THROUGH THE STRAITS AND NORTHERN LAKE HURON. A SERIES
OF MID LEVEL DISTURBANCES HAVE BEEN INITIATING ROUNDS OF SHOWERS AND
THUNDERSTORMS WHICH WILL CONTINUE TO OCCUR THROUGH WEDNESDAY UNTIL
THE COLD FRONT DROPS THROUGH. ANY BREAK IN THE RAIN WILL BE SHORT
LIVED AS THE FRONT LIFTS BACK NORTH ON THURSDAY PROVIDING ADDITIONAL
CHANCES OF STORMS. WINDS WILL BE FLUCTUATING ALOT THIS WEEK WITH THE
FREQUENCY OF FRONTAL PASSAGES. THE WEAK GRADIENT WILL KEEP SPEEDS
DOWN THROUGH THE WEEK THOUGH WITH MAX WIND GUSTS RARELY TOUCHING 20
KNOTS. THE SLIGHTLY COOLER AIR OVER THE WATERS BRINGS CHANCES OF
WATERSPOUTS WITH ANY OF THE STORMS OVER THE LAKES THIS WEEK.
PREV DISCUSSION
ISSUED AT 122 PM EDT MON AUG 31 2026
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.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...SF
MARINE.......DRK
AVIATION.....CB
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