328
FXUS63 KDTX 191902
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
302 PM EDT SAT JUL 19 2025
KEY MESSAGES
- SCATTERED TO POTENTIALLY NUMEROUS SHOWERS AND THUNDERSTORMS
DEVELOPING THIS EVENING. ISOLATED SEVERE THUNDERSTORMS ARE
POSSIBLE IN THE 4 PM TO 10 PM WINDOW.
- THE MAIN HAZARD WITH ANY SEVERE THUNDERSTORM WILL BE DAMAGING WINDS
GUSTS OF 60+ MPH. SECONDARY HAZARDS WILL BE LARGE HAIL TO AN INCH
AND/OR ISOLATED TORNADOES.
- DRY CONDITIONS SUNDAY THROUGH TUESDAY.
- HEAT AND A LOW CHANCE OF THUNDERSTORMS RETURN MID WEEK, WITH HEAT
INDICES APPROACHING 100 DEGREES ON THURSDAY.
DISCUSSION
NO MAJOR CHANGES FOR THIS AFTERNOON AND EVENING FROM THE LATE
MORNING UPDATE, POSTED BELOW FOR COMPLETION WITH MINOR UPDATES, IN
ADDITION TO THE EXTENDED FORECAST:
REMNANTS OF AN MCV FEATURE WILL SWEEP ACROSS SOUTHERN MICHIGAN
THROUGH THE REMAINING AFTERNOON HOURS WITH ADDITIONAL ISOLATED
DEVELOPMENT JUST AHEAD AND NORTH OF THIS FEATURE, ALONG A WARM FRONT
AND WITHIN A LARGE RIBBON OF ENHANCED THETA-E. THE ENVIRONMENT FOR
LATE THIS AFTERNOON AND EVENING REMAINS CHARACTERIZED BY NEBULOUS
FORCING UNDER MODEST INSTABILITY AND DECENT KINEMATICS. ADDITIONAL
SOURCES FOR SHOWER AND THUNDERSTORM LATE TONIGHT WILL BE AHEAD OF AND
ALONG A COLD FRONT THAT WILL SWEEP FROM NORTHWEST TO SOUTHEAST
ACROSS SE MI BETWEEN 23Z-06Z TONIGHT, UNDER THE FAVORABLE RIGHT
ENTRANCE REGION OF THE UPPER-LEVEL JET. THIS WILL BRING HIGHER END
POP CHANCES (50-70%) TO SE MI TONIGHT.
KINEMATICALLY, THE SHEAR PROFILES ARE DECENT, NOTING THE STRONGER
WIND PROFILES IN THE MID-LEVELS WHICH ELEVATE SLIGHTLY LATE THIS
AFTERNOON AND EVENING. 1-6KM BULK SHEAR WILL RANGE BETWEEN 25 TO 35
KNOTS, THE HIGHEST FOUND OVER THE NORTHERN-THIRD OF THE CWA. THIS
WILL BE A POSITIVE FOR ORGANIZED CONVECTION AS INSTABILITY SLOWLY
BUILDS IN THROUGH THE AFTERNOON. THE MAJOR CAVEAT CONTINUES TO BE
THE DEGREE OF INSTABILITY THAT CAN PULL IN AHEAD OF ANY STORM
DEVELOPMENT. MOSTLY CLOUDY SKIES HAVE HELD ACROSS SE MI THROUGH THE
AFTERNOON, ENFORCED WITH CIRROSTRATUS FROM UPSTREAM ACTIVITY WHICH
HAS LIMITED THE DEGREE OF AFTERNOON HEATING. DEW POINTS REMAIN IN
THE MID TO UPPER 60S WITH LOCAL MAXIMUMS IN THE LOW 70S HOLDING
ACROSS THE WEST SIDE OF THE STATE. HI-RES OUTPUT HOLDS SBCAPE VALUES
BETWEEN 500-1000 J/KG ACROSS SE MI, WITH SPC MESOANALYSIS
FORECASTING A LITTLE MORE AGGRESSIVE VALUES JUST ABOVE 1000 J/KG. THE
BETTER THERMODYNAMICS WILL LIKELY RESIDE THROUGH WEST AND CENTRAL
MICHIGAN, INTO THE TRI-CITIES, ALIGNING WITH ARC OF BETTER MOISTURE.
OVERALL, THIS SETUP STILL WARRANTS THE CONTINUED MENTION FOR
ISOLATED SEVERE WEATHER DEVELOPMENT, BUT SEVERE TRENDS HAVE TRENDED
DOWNWARD. SHOWER AND STORMS WILL BE FAVORED BETWEEN THE 4PM-10PM
TIME FRAME. STORM MODE WILL LIKELY RANGE BETWEEN ISOLATED TO
MULTICELL CLUSTER WITH ISOLATED DAMAGING GUSTS FROM WET MICROBURSTS
THE PRIMARY HAZARD. LARGE HAIL AND AN ISOLATED TORNADO ARE SECONDARY
HAZARDS, BUT CANNOT BE RULED OUT UNDER ANY ORGANIZED UPDRAFTS. ANY
SORT OF ROTATING UPDRAFTS WOULD BE FAVORED MORE OVER CENTRAL
MICHIGAN INTO THE TRI-CITIES, ALIGNING WITH THE STRONGEST CAPE
DENSITY AND NOTING BETTER CURVATURE IN THE MID-LEVELS OF SR-
HODOGRAPHS WITH A VERY SLIGHT ELONGATION TO THE 0-1KM SEGMENT.
PASSAGE OF A WEAK LOW PRESSURE SYSTEM TRANSVERSING ACROSS NORTHERN
LOWER MICHIGAN INTO ONTARIO WILL DRAW A COLD FRONT ACROSS THE STATE
LATE TONIGHT THROUGH TOMORROW MORNING, BOOSTED FROM HIGH PRESSURE
FILLING WITHIN ITS WAKE. THE FRONT WILL SLOW ACROSS THE NORTHERN
OHIO VALLEY TOMORROW AFTERNOON WHICH BRINGS LOW END CHANCES FOR
SHOWERS TO BRUSH SOUTHERN MICHIGAN TOMORROW MORNING AND AFTERNOON,
BUT OTHERWISE HIGH PRESSURE BRINGS STABLE CONDITIONS AND DRY WEATHER
TO THE REGION THROUGH TUESDAY. HIGH PRESSURE WILL DEPART INTO THE
WEST ATLANTIC BY THE MIDWEEK PERIOD WHICH WILL STREAM IN HOTTER
TEMPERATURES FROM THE PLAINS INTO THE GREAT LAKES WHERE A 594 DAM
RIDGE WILL BECOME ESTABLISHED. 850MB TEMPERATURES AOA 20C BRING
INCREASINGLY LIKELY CHANCES TO SEE TEMPERATURE HIGHS RETURN INTO THE
90S WED-THU, AND POSSIBLY THROUGH FRIDAY PENDING TIMING OF A
POTENTIAL COLD FRONT AND STORM CHANCES. MEDIUM RANGE MODELS HAVE
TRENDED DRIER THROUGH THE MIDWEEK PERIOD WITH THE STRONGER RIDGE IN
PLACE, BUT LOW-END POP CHANCES HOLD, GIVEN THE CHANCE TO SEE
SHORTWAVE FEATURES ROUND THE RIDGE. PASSAGE OF THIS COLD FRONT LATE
THURSDAY INTO FRIDAY BRINGS THE BETTER CHANCES FOR SHOWER AND
THUNDERSTORMS.
MARINE
QUIETER CONDITIONS THIS AFTERNOON WILL GIVE WAY TO UNSETTLED
CONDITIONS LATER TODAY AS A LOW PRESSURE SYSTEM TRACKS EAST AND
CROSSES LAKE HURON LATER THIS EVENING. THIS SYSTEM ADVECTS A HUMID,
UNSTABLE AIR MASS WITH SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS DEVELOPING THIS AFTERNOON AND INTO THE OVERNIGHT
HOURS. AMBIENT WIND SPEEDS AND WAVE HEIGHTS WILL HOLD BELOW SMALL
CRAFT ADVISORY CRITERIA BUT ISOLATED TO SCATTERED SEVERE STORMS WILL
BE CAPABLE OF PRODUCING GUSTS IN EXCESS OF 40 KT, HAIL, AND
WATERSPOUTS. THE COLD FRONT CLEARS THE AREA SUNDAY MORNING WITH
DRIER CONDITIONS AND MODERATE NORTH WIND TO WRAP UP THE WEEKEND.
HIGH PRESSURE PASSING TO THE NORTH CAUSES LIGHT WIND TO VEER TO
EASTERLY ON MONDAY. THE NEXT CHANCE OF THUNDERSTORMS LOOKS TO HOLD
OFF UNTIL TUESDAY NIGHT INTO WEDNESDAY ALONG A WARM FRONT MOVING IN
FROM THE MIDWEST.
HYDROLOGY
NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
SOUTHEAST MICHIGAN LATE TODAY AND THIS EVENING. BASIN AVERAGED
RAINFALL TOTALS WILL RANGE BETWEEN A QUARTER-INCH TO A HALF- INCH,
HOWEVER, ANY STRONG THUNDERSTORM WILL BE CAPABLE OF QUICKLY
PRODUCING LOCALIZED RAINFALL TOTALS BETWEEN 1 TO 2 INCHES. GIVEN
FASTER STORM MOTIONS, OVERALL FLOODING CONCERNS REMAIN LOW, HOWEVER,
HIGHLY LOCALIZED FLOODING REMAINS POSSIBLE ACROSS URBAN AREAS AND
LOW-LYING FLOOD PRONE LOCATIONS.
PREV DISCUSSION
ISSUED AT 1241 PM EDT SAT JUL 19 2025
AVIATION...
HIGHLY VARIED CLOUD SCENE ACROSS THE SOUTHEAST MICHIGAN AIRSPACE
EARLY THIS AFTERNOON. MVFR CLOUDS HAVE EXPANDED IN COVERAGE FROM FNT
AND NORTHWARD. THIS MAIN BATCH WILL SLIP NORTHEAST ACROSS THE THUMB
THROUGH THE AFTERNOON. SMALL SCALE DIURNAL CUMULUS HAS QUICKLY
EMERGED WITH THE INCREASE IN NEAR SURFACE MOISTURE AS AN UPPER LEVEL
WAVE AND NEAR SURFACE COLD APPROACH THE REGION. THE SMALL SCALE
NATURE INDICATES A RATHER SHALLOW BOUNDARY LAYER AT THE TIME.
FARTHER UPSTREAM, WIDESPREAD BOUNDARY CLOUD EXPANSION AND HIGH
CLOUDS INDUCED FROM THE MORNING CONVECTION ACROSS THE MISSISSIPPI
VALLEY WILL WASH ACROSS. THE ONGOING CONVECTION NEAR CHICAGO AND
SOUTHERN LAKE MICHIGAN MARKS THE AXIS OF GREATEST LIKELIHOOD FOR
ADDITIONAL DEVELOPMENT THIS AFTERNOON AND EVENING AS THE FORCING
MECHANISMS CROSS LOWER MICHIGAN. OVERALL TIMING APPEARS DELAYED
SLIGHTLY COMPARED TO EARLIER FORECASTS, WITH ARRIVAL TIMES BEING
MORE IN THE 21-23Z WINDOW AND A DEPARTURE IN THE 00-02Z. THERE ARE
SIGNS IN THE MOST RECENT HIRES GUIDANCE THE BETTER CONVECTIVE
COVERAGE WILL BE FROM PTK NORTH - WHERE INSTABILITY WILL BE SLIGHTLY
MORE ABUNDANT.
A COLD FRONT WILL SETTLE THROUGH THE AREA OVERNIGHT, WHICH WILL
USHER IN NORTHERLY FLOW AND EVENTUALLY COOLING AND DRYING. THE
IMMEDIATE POST-FRONTAL ENVIRONMENT IS EXPECTED TO SUPPORT MVFR
CLOUDS UNTIL MID-MORNING SUNDAY - AFTER WHICH MORE AGGRESSIVE DRYING
THROUGH MIXING WILL CLEAR OUT THE BOUNDARY LAYER - LEAVING A MID-
CLOUD DECK OVERHEAD.
FOR DTW/D21 CONVECTION...CONVECTIVE REGENERATION ASSOCIATED WITH
ONGOING ACTIVITY NEAR CHICAGO WILL ARRIVE AFTER 21Z AND LIKELY
DEPART AROUND 01-02Z WINDOW. STORM ORGANIZATION IS EXPECTED TO BE
BEST ACROSS THE NORTHERN SECTIONS OF THE AIRSPACE.
THRESHOLD PROBABILITIES...
* MEDIUM FOR CEILINGS AT OR BELOW 5000-FT THIS AFTERNOON AND
EVENING. HIGH TONIGHT.
* MEDIUM FOR THUNDERSTORMS LATE THIS AFTERNOON AND EVENING. LOW
TONIGHT, AFTER MIDNIGHT.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...AM
MARINE.......TF/SS
HYDROLOGY....AM
AVIATION.....MANN
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