348
FXUS63 KDTX 300818
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
418 AM EDT SUN MAR 30 2025
KEY MESSAGES
* MOSTLY DRY BY LATE THIS MORNING AND EARLY AFTERNOON BEFORE RAIN
SHOWERS AND THUNDERSTORMS INCREASE COVERAGE LATER TODAY.
* THERE IS A SLIGHT RISK (2/5) OF SEVERE THUNDERSTORMS MAINLY BETWEEN
6 PM AND 11 PM THIS AFTERNOON AND EVENING. DAMAGING WINDS, LARGE
HAIL, HEAVY RAINFALL, AND AN ISOLATED TORNADO ARE ALL POSSIBLE.
* HIGH TEMPERATURES MOSTLY IN THE 40S FOR MONDAY INTO TUESDAY BEFORE
THE NEXT ROUND OF WARMER WEATHER WITH SHOWERS AND THUNDERSTORMS
RETURNS WEDNESDAY.
DISCUSSION
STALLED FRONTAL BOUNDARY REMAINS DRAPED ACROSS SOUTHEAST MICHIGAN
AROUND THE M-59 CORRIDOR MAINTAINING THE SHARP NORTH TO SOUTH
TEMPERATURE GRADIENT. OBSERVATIONS SHOW NE WINDS AND MID 30S ACROSS
THE THUMB/SAGINAW VALLEY AND S-SE WINDS AND MID/UPPER 50S ACROSS
DETROIT AND SOUTHERN MICHIGAN BORDER. INCREASING SOUTHWEST WINDS FROM
A 35-40 KNOT JET AT 850 MB HAS BROUGHT ELEVATED MOISTURE WITH TIES
TO THE GULF INTO MICHIGAN WHICH IS SUPPORTING THE EARLY MORNING
SHOWERS. LIMITED INSTABILITY WITHIN THE THETA-E RIDGE SHOULD KEEP ANY
LIGHTING POTENTIAL AT BAY THROUGH THE MORNING.
THE STALLED FRONTAL BOUNDARY IS FORECAST TO LIFT NORTHWARD INTO THE
SAGINAW VALLEY THROUGHOUT THE MORNING IN RESPONSE TO THE UPSTREAM
LOW PRESSURE SYSTEM THAT LIFTS NORTHEAST ACROSS THE MIDWEST AND
DIRECTLY OVER NORTH/CENTRAL LOWER MICHIGAN THIS EVENING. A DRY SLOT
WILL ACCOMPANY THE NORTHWARD EXPANDING WARM SECTOR THIS MORNING
RESULTING IN LIMITED PRECIPITATION CHANCES AFTER 11 AM THIS MORNING
INTO THE EARLY/MID AFTERNOON. FORECAST REMAINS FOCUSED ON THE
POTENTIAL FOR SEVERE WEATHER LATER THIS AFTERNOON AND EVENING.
MODELS CONTINUE TO SHOW DECENT INSTABILITY CHARACTERIZED BY MLCAPES
OF 500-1000 J/KG BUILDING ACROSS THE CWA BY 4 PM AS DEWPOINTS
APPROACH OR ACHIEVE 60 DEGREES. IF BREAKS IN THE CLOUDS OCCUR,
SLIGHTLY GREATER INSTABILITY WILL BE ACHIEVABLE. DEEP LAYER SHEAR
WILL INCREASE IN THE SOUTHEAST QUADRANT OF THIS SYSTEM WITH 50 TO 70
KNOT OF LOW TO MID LEVEL FLOW RESULTING IN MEAN 0-6 KM BULK SHEAR
VALUES OF 30-40 KNOTS. SHEAR IS LARGELY UNIDIRECTIONAL/PARALLEL TO
THE ADVANCING COLD FRONT. THIS FAVORS A MORE QUASI-LINEAR STORM
MODE, WHICH IS LARGELY WHAT HI-RES MODELS DEPICT. THIS MAKES DAMAGING
WINDS THE MAIN HAZARD. STORM-RELATIVE HODOGRAPHS DO POINT TOWARDS
SOME LOW LEVEL CURVATURE. THUS, AN ISOLATED TORNADO RISK EXISTS IF
ANY EMBEDDED SUPERCELL STRUCTURES OR ANY DISCRETE CELLS CAN EXHIBIT A
MORE EASTWARD STORM MOTION. THIS WOULD BE ESPECIALLY TRUE TOWARDS
THE SURFACE WARM FRONT IF IT IS LINGERING AROUND THE SAGINAW
VALLEY/NORTHERN THUMB AND ENOUGH INSTABILITY CAN GET SHOVED THAT FAR
NORTH. THE 00Z RAOB FROM LAST NIGHT SHOWS PRECIPITABLE WATER TO
AROUND 1.25 INCHES, WHICH IS IN THE 90TH TO 98TH CLIMATOLOGICAL
PERCENTILE, SUPPORTING A LOCALLY HEAVY RAINFALL THREAT AS WELL.
LARGE HAIL APPEARS TO BE A SECONDARY RISK, BUT REMAINS POSSIBLE GIVEN
THE RELATIVELY LOW FREEZING LEVELS. MAIN TIMING OF SEVERE WEATHER
HAS TRENDED TOWARDS 6 PM TO 11 PM WITH A SLIGHT RISK STILL IN PLACE
FOR MOST OF SOUTHEAST MICHIGAN.
THE LOW PRESSURE SYSTEM WILL THEN TRACK INTO ONTARIO WITH THE STRONG
COLD FRONT SWEEPING THROUGH SOUTHEAST MICHIGAN TONIGHT WITH DRY AIR
QUICKLY DRIVING THROUGH MICHIGAN. THIS WILL HELP PRECIPITATION COME
TO AN END BEFORE THERE IS A MUCH CHANCE FOR ANY LINGERING SHOWERS
LATE TONIGHT/EARLY TOMORROW MORNING. SAGINAW VALLEY AND THUMB WOULD
STAND THE BEST CHANCE TO SEE A FEW SNOWFLAKES IF THEY DO OCCUR. DRY
CONDITIONS THEN EXPECTED FOR MONDAY AND TUESDAY. DAYTIME HIGHS
RETURN TO THE AVERAGE FOR THIS TIME OF YEAR. DAYTIME HIGHS MOSTLY IN
THE 40S MONDAY AND TUESDAY WITH PARTS OF THE THUMB HOLDING IN THE
30S. COLDEST NIGHT OF THE WEEK WILL BE MONDAY NIGHT INTO TUESDAY
MORNING WITH WIDESPREAD LOWS DOWN INTO THE MID 20S.
THE NEXT LOW PRESSURE SYSTEM IS SET TO IMPACT THE MIDWEST TUESDAY
NIGHT AND WEDNESDAY. EXPECT TEMPERATURES TO WARM BACK INTO THE 60S
WITH RESULTANT WARM AND MOIST ADVECTION INTO MICHIGAN. A PLUME OF
GULF MOISTURE WILL AGAIN SUPPORT A HIGH LIKELIHOOD OF RAIN AND
THUNDERSTORMS WITH THE POTENTIAL FOR HEAVY RAINFALL AND POSSIBLY SOME
SEVERE THUNDERSTORMS ON WEDNESDAY.
MARINE
LINGERING STALLED WARM FRONTAL BOUNDARY IS GRADUALLY FORCED BACK
NORTHWARD STARTING EARLY THIS MORNING AND CONTINUES THROUGH THE
MAJORITY OF THE DAY AS A FINAL, STRONGER LOW PRESSURE CENTER LIFTS
ACROSS THE WESTERN GREAT LAKES. WINDS SHIFT TO SOUTHERLY FOR ALL BUT
NORTHERN LAKE HURON AS A RESULT THOUGH GUSTS REMAIN MODEST, AROUND
OR BELOW 20KTS. NE GUSTS OVER NORTHERN LAKE HURON LIKELY ARE
STRONGER, AROUND 25-30KTS, THIS MORNING BEFORE WEAKENING BY
AFTERNOON AS THE LOW CENTER APPROACHES. SCATTERED THUNDERSTORMS ARE
POSSIBLE THIS AFTERNOON THOUGH GREATEST WINDOW FOR STORMS ARRIVES IN
THE EVENING IN ADVANCE OF THE ATTENDANT COLD FRONT. NUMEROUS SHOWERS
AND SCATTERED T-STORMS ARE LIKELY DURING THE EVENING WITH SOME OF
THESE STORMS BEING STRONG TO SEVERE- GREATEST THREATS ARE WIND GUSTS
OVER 34KTS AND LIGHTNING WITH SECONDARY, LOWER CHANCE, THREATS BEING
HAIL AND AN ISOLATED TORNADIC WATERSPOUT (MAINLY OVER THE SOUTHERN
GREAT LAKES). SURFACE LOW TRACKS DIRECTLY OVER LAKE HURON EARLY
SUNDAY NIGHT USHERING IN COLDER NORTHWEST FLOW FOR MONDAY. LOW
RAPIDLY PUSHES INTO EASTERN CANADA RESULTING IN A WEAKENING GRADIENT
OVER THE CENTRAL GREAT LAKES WHICH IS EXPECTED TO KEEP NW GUSTS
GENERALLY BELOW 30KTS. HIGH PRESSURE THEN BUILDS OVER THE REGION FOR
TUESDAY BRINGING DRIER CONDITIONS AND LIGHTER WINDS.
HYDROLOGY
A LOW PRESSURE SYSTEM WILL MOVE IN FROM THE MIDWEST THIS AFTERNOON
USHERING IN ADDITIONAL GULF MOISTURE. THIS ENVIRONMENT IS SUPPORTIVE
OF HEAVIER SHOWERS AND INCREASED COVERAGE OF THUNDERSTORMS.
ADDITIONAL RAINFALL TOTALS FOR TODAY AND TONIGHT WILL BE FROM A
QUARTER INCH TO A HALF INCH ON AVERAGE WITH THE MAJORITY FALLING
BETWEEN 2 PM TODAY AND MIDNIGHT TONIGHT. LOCALLY HIGHER TOTALS TO AN
INCH WILL BE POSSIBLE WITH MORE ORGANIZED THUNDERSTORMS. RAINFALL
WITH THE SYSTEM LATE THIS AFTERNOON AND EVENING SHOULD BE RATHER
PROGRESSIVE AND ONLY RESULTS IN MINOR PONDING OF WATER IN PRONE
AREAS ALONG WITH RISES IN AREA CREEKS AND STREAMS. HIGHER IMPACT
FLOODING IS NOT LIKELY AT THIS TIME.
PREV DISCUSSION
ISSUED AT 1144 PM EDT SAT MAR 29 2025
AVIATION...
THE FRONTAL BOUNDARY THAT HAS BEEN STALLED JUST NORTH OF PTK WILL
SLOWLY LIFT NORTH AS A WARM FRONT DURING THE MORNING AS SOUTH FLOW
WITHIN THE WARM SECTOR INCREASES WITH AN APPROACHING LOW PRESSURE
SYSTEM. IFR AND LIFR CONDITIONS WILL CONTINUE TO PREVAIL ON THE COLD
SIDE OF THE FRONT, AFFECTING MBS AND FNT INTO SUN MORNING. LIGHT
RAIN WILL PERSIST THROUGH DAYBREAK. THE DEEP LAYER MOISTURE PLUME
WILL THEN EXIT TO THE EAST, STRIPPING MID LEVEL MOISTURE AND JUST
LEAVING LINGERING LOW CLOUDS AND DRIZZLE. THERE IS AT LEAST SOME
SUPPORT FROM OBS ACROSS NW INDIANA THAT ONGOING MOISTURE ADVECTION
WITHIN THE WARM SECTOR WILL DRIVE MVFR AND SOME IFR CEILINGS INTO
METRO DETROIT DURING THE MORNING. THERE WILL BE SOME IMPROVEMENT IN
CEILINGS DURING THE DAY SUNDAY, ALTHOUGH A SUBSIDENCE INVERSION IS
LIKELY TO HOLD A FAIR AMOUNT OF MVFR BASED CLOUDS THROUGH MUCH IF
NOT ALL OF THE AFTERNOON.
FOR DTW...ALTHOUGH THERE IS SOME UNCERTAINTY AS TO HOW FAR NORTH
SURFACE BASED INSTABILITY WILL REACH LATE SUNDAY, ELEVATED
INSTABILITY APPEARS ENOUGH TO CARRY A CHANCE OF THUNDERSTORMS SUNDAY
EVENING, MOST LIKELY BETWEEN 00Z AND 03Z. AVAILABLE INSTABILITY IS
FORECAST TO WANE AS ANY THUNDERSTORMS ADVANCE ACROSS METRO DETROIT,
POSSIBLY LEADING TO A DECREASE IN COVERAGE. THE CURRENT HI RES
GUIDANCE SUGGESTS THE POTENTIAL FOR LINEAR CONVECTION TO CROSS THE
AIRSPACE, MOST PROBABLE ACROSS THE SOUTHERN PORTION OF THE AIRSPACE.
DTW THRESHOLD PROBABILITIES...
* HIGH IN CEILINGS AOB 5000 FEET SUNDAY.
* MODERATE IN THUNDERSTORMS SUNDAY EVENING.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR LHZ421-441.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...AA
MARINE.......KDK
HYDROLOGY....AA
AVIATION.....SC
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AT WWW.WEATHER.GOV/DETROIT.
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