829
FXUS63 KDTX 041746
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
146 PM EDT SAT APR 4 2026
KEY MESSAGES
- WIDESPREAD SHOWERS PERSIST FOR THE SAGINAW VALLEY AND THUMB THROUGH EARLY
AFTERNOON.
- INCREASED RAIN CHANCES THIS AFTERNOON WITH THUNDERSTORMS POSSIBLE
SOUTH OF M-59 AS A COLD FRONT TRACKS THROUGH.
- A FEW STRONG TO SEVERE THUNDERSTORMS POSSIBLE NEAR THE OHIO BORDER.
DAMAGING WINDS ARE THE PRIMARY THREAT, BUT A TORNADO CANNOT BE
COMPLETELY RULED OUT.
- BELOW NORMAL TEMPERATURES SUNDAY THROUGH EARLY NEXT WEEK.
AVIATION
WHILE A POCKET OF VFR SKIES HAVE DEVELOPED ACROSS THE SOUTHERN METRO
TERMINALS, THESE WILL QUICKLY FILL BACK INTO IFR TO MVFR AS A LINE
OF SHOWERS AND THUNDERSTORMS MARCHES THROUGH SOUTHEAST MICHIGAN THIS
AFTERNOON. ONGOING SHOWERS ALONG THE LINE CURRENTLY ACROSS MBS AND
FNT WILL EVENTUALLY MOVE EASTWARD AND PICK UP INTENSITY DURING THE
19Z TO 22Z PERIOD. GREATEST THUNDERSTORMS THREAT WILL BE ACROSS THE
SOUTH NEAR THE BETTER INSTABILITY, BUT WILL MAINTAIN A WINDOW FOR
THUNDERSTORMS ACROSS THE NORTH FOR ELEVATED THUNDER. THE OVERNIGHT
PERIOD CARRIES SOME UNCERTAINTY WITH CLOUD TRENDS, BUT WILL MAINTAIN
A LOWER IFR/MVFR CLOUD DECK INTO THE OVERNIGHT. WEST WINDS WILL BE
GUSTY TO 20-25 KNOTS BEHIND THE FRONT THIS EVENING.
FOR DTW...LINE OF SHOWERS AND POTENTIAL FOR STRONG THUNDERSTORMS TO
DEVELOP BETWEEN 19Z AND 22Z TODAY. SURFACE INSTABILITY WILL STRUGGLE
TO LIFT TOWARDS THE METRO TERMINALS, BUT ELEVATED THUNDERSTORMS WITH
GUSTY THUNDERSTORMS WINDS WILL BE POSSIBLE IN THIS TIME FRAME.
DTW THRESHOLD PROBABILITIES
* HIGH FOR CEILING AT OR BELOW 5000 FT THROUGH THIS AFTERNOON. LOW
TONIGHT.
* MODERATE FOR THUNDERSTORMS BETWEEN 19Z AND 22Z THIS AFTERNOON.
PREV DISCUSSION
ISSUED AT 1025 AM EDT SAT APR 4 2026
UPDATE...
RADAR RETURNS THIS MORNING SHOW A MUCH MORE VIGOROUS ISENTROPIC
RESPONSE THAN MODEL PROJECTIONS, AS WIDESPREAD STEADY RAIN IS
ONGOING NORTH OF THE I-94 CORRIDOR. THERE WAS A FLARE UP IN ELEVATED
CONVECTION EARLIER THIS MORNING AT THE LEAD EDGE OF THE LOW LEVEL
JET, WHICH LED TO A BRIEF ENHANCEMENT IN RAINFALL RATES AND
LOCALIZED AMOUNTS OF 2+ INCHES FOR THE NORTHERN SUBURBS. THE
CONVECTIVE COMPONENT HAS SINCE SUBSIDED WITH A DRYING TREND NOTED
UPSTREAM, ALLEVIATING ANY IMMEDIATE CONCERNS FOR FLASH FLOODING.
RISES ON AREA RIVERS AND PONDING ON ROADWAYS WILL BE THE MAIN
IMPACTS THROUGH THE MORNING. LULL IN PRECIPITATION STILL IN PLAY MID-
DAY, MAINLY FOR SOUTHERN PORTIONS OF THE FORECAST AREA WHERE SHOWER
COVERAGE HAS BEEN MORE LIMITED ALREADY. POPS HAVE BEEN INCREASED
FOR THE REST OF THE DAY FOR THE SAGINAW VALLEY AND THUMB.
NO MAJOR CHANGES TO THIS MORNING'S DISCUSSION ON SEVERE POTENTIAL
(SEE BELOW). CONFIDENCE IS STILL LOW IN THE ABILITY OF THE WARM
FRONT TO LIFT THIS FAR NORTH, AS IT IS CURRENTLY STALLED FROM
ROUGHLY SOUTH BEND TO DEFIANCE. BUMPED DAYTIME HIGHS DOWN A FEW
DEGREES GIVEN THE STALLED TREND. IF ANYTHING, THE HIGHER COVERAGE OF
SHOWERS THIS MORNING ADDS STABILITY TO THE BOUNDARY LAYER
(ESPECIALLY NORTH OF I-94), INCREASING CONFIDENCE THAT THE MAIN
SEVERE THREAT STAYS SOUTH OF I-94, WITH A NARROW TIME WINDOW
(2PM-6PM) AND GEOGRAPHIC FOOTPRINT. NO CHANGES TO THE PRIMARY THREAT
OF LOCALIZED GUST POTENTIAL TO 60 MPH, WITH A VERY LOW TORNADO THREAT
IF ANY MARINE LAYER INTERACTION ENSUES.
HYDROLOGY...
SEVERAL ROUNDS OF SCATTERED TO WIDESPREAD RAIN THIS MORNING WITH
EMBEDDED ISOLATED THUNDERSTORMS ARE EXPECTED THROUGH THE MORNING
HOURS. A LULL IN PRECIPITATION WILL BE LIKELY ACROSS SOUTHERN
MICHIGAN, BEFORE A COLD FRONT THEN BRINGS A LINE OF WIDESPREAD
SHOWERS AND EMBEDDED THUNDERSTORMS THIS AFTERNOON AND EVENING. THE
TRI-CITIES AND NORTHERN THUMB WILL EXPERIENCE LONGER RESIDENCE TIME
FOR PRECIPITATION TODAY GIVEN THE TRACK OF THE LOW PRESSURE SYSTEM.
THIS BRINGS INCREASING PROBABILITIES FOR LOCAL TOTALS TO ACHIEVE OR
EXCEED 1", WITH THE CURRENT FORECAST HIGHLIGHTING POSSIBLY TOTALS
BETWEEN 1 TO 1.5" ACROSS THE TRI-CITIES AND NORTHERN THUMB.
FOR LOCATIONS SOUTH, BASIN AVERAGES RANGE BETWEEN A HALF-INCH TO
THREE-QUARTER INCHES. HOWEVER, ANY THUNDERSTORM ACTIVITY WILL BE
CAPABLE OF PRODUCING LOCALIZED TOTAL NEARING OR EXCEEDING 1".
SEVERAL RIVER FLOOD WARNINGS ARE IN EFFECT ACROSS THE SAGINAW RIVER.
LOCALIZED FLOODING IN LOW-LYING OR FLOOD PRONE AREAS REMAIN POSSIBLE
WITH ANY THUNDERSTORM ACTIVITY.
PREV DISCUSSION...
ISSUED AT 348 AM EDT SAT APR 4 2026
DISCUSSION...
OCCLUDED LOW PRESSURE SYSTEM NOW OVER NORTHERN ILLINOIS AND SOUTHERN
WISCONSIN WILL CONTINUE TO PROGRESS ACROSS NORTHERN LOWER MICHIGAN
THIS AFTERNOON BEFORE DEPARTING INTO EASTERN ONTARIO AND QUEBEC BY
LATE TONIGHT. PROGRESSION OF THE LOW HAS RESULTED IN NUMEROUS RAIN
SHOWERS WITH SOME EMBEDDED THUNDERSTORMS ACROSS SE MI WITH SHALLOW
ISENTROPIC ASCENT ALONG AN ADVANCING WARM FRONT. ISOLATED
THUNDERSTORMS WITH HEAVY DOWNPOURS REMAIN POSSIBLE THROUGH THE
MORNING HOURS, CAPITALIZING ON MODEST MUCAPE, BUT ACTIVITY REMAINS
ELEVATED NOTING THE SHARP INVERSION IN THE LOW LEVELS WITH THE 00Z
RAOB. THE 40+ KNOTS LLJ ON THE SOUTHERN FLANK OF THE LOW WILL RESULT
IN EXTREMELY EFFICIENT MOISTURE TRANSPORT WITH PW VALUES AROUND 1.40
INCHES, WHICH IF VERIFIED WOULD FALL OUTSIDE RECORD VALUES FOR EARLY
APRIL PER LOCAL SOUNDING CLIMATOLOGY. MOISTURE CONVERGENCE WITH
ADDITIONAL FORCING AHEAD AND ALONG OF A COLD FRONT WILL BRING
WIDESPREAD RAIN AND EMBEDDED THUNDERSTORMS THROUGH THE AFTERNOON AND
EVENING. A LULL IN ACTIVITY WILL BE LIKELY ACROSS THE METRO REGION
AND DOWN INTO THE MI/OH BORDER LATER THIS MORNING, WITH PROLONGED
RAIN CHANCES SETTING UP THROUGH THE TRI-CITIES, WHERE THE LOW AND
OCCLUDED FRONT LIES. THIS WILL COINCIDE WITH THE HIGHER RAINFALL
TOTALS, AS DESCRIBED IN THE HYDROLOGY SECTION.
LATEST 12Z DATA HIGHLIGHTS A SMALL WINDOW FOR SOME ISOLATED STRONG
TO SEVERE STORMS FROM ROUGHLY 18Z (2PM) TO 22Z (6PM), FAVORED ALONG
OR SOUTH OF I-94, WHERE SURFACE BASED CAPE BRIEFLY WEDGES IN AHEAD OF
THE COLD FRONT. HREF MEAN CAPE VALUES RANGE FROM AROUND 800 J/KG
DOWN TO THE MI/OH BORDER AND UPWARDS TO 300 J/KG ACROSS THE METRO
REGION. HODOGRAPHS ARE RELATIVE STRAIGHT FROM 0-3KM OWING TO THE
UNIDIRECTIONAL WINDS. ANY TYPE OF DEVELOPMENT JUST AHEAD OR ALONG THE
COLD FRONT COULD HAVE SOME BETTER STRUCTURE WITH SOME BOWING THAT
WOULD BE CAPABLE OF PRODUCING DAMAGING WIND GUSTS WITH LOCALIZED GUST
POTENTIAL TO AROUND 60 MPH. ML-OUTPUT HIGHLIGHTS A SLIGHTLY ELEVATED
CHANCE FOR TORNADO PROBABILITIES WITHIN THE SAME AREA -- 0-3 KM
SHEAR VECTOR ORIENTATION IS POOR RELATIVE TO THE PROJECTED STORM
MOTION AND 0-1KM HODOGRAPHS ARE NOT CONDUCIVE TO TORNADOGENESIS.
HOWEVER, CANNOT RULE OUT SOME HIGHLY LOCALIZED STREAMWISE VORTICITY
DRIVEN BY BACKED SURFACE WINDS ALONG THE MARINE LAYER INTERFACE. ANY
OVERACHIEVEMENT OF INSTABILITY COULD EXPAND THE FOOTPRINT FOR STRONG
TO SEVERE POTENTIAL INTO THE NORTH METRO REGION THROUGH PORT HURON AS
HIGHLIGHTED IN THE LATEST SWODY1, BUT CONFIDENCE IN THIS EXPANDED
FOOTPRINT IS LOW.
THE STRONG COLD FRONT MOVES THROUGH BY THE LATE EVENING, ENDING ALL
RAIN CHANCES WHILE ADVECTING IN MUCH COOLER AIR. LOWS DROP INTO THE
30S SUNDAY MORNING, WHICH PAVES THE WAY FOR BELOW NORMAL
TEMPERATURES TO LAST THROUGH THE EARLY WEEK PERIOD. THE NEXT LIKELY
CHANCE FOR SOME WINTRY PRECIPITATION THEN ENTERS ON MONDAY AS A
SERIES OF SHORTWAVES ARRIVE ACROSS THE GREAT LAKES. MORNING
TEMPERATURES IN THE 30S BRING THE CHANCE FOR MELTING SNOW TO A
RAIN/SNOW MIX. TEMPERATURES WARM UP INTO THE 40S BY THE AFTERNOON
BRINGING INCREASING CHANCES FOR RAIN, BUT STEEP LAPSE RATES AND LOWER
FREEZING LEVELS COULD BRING SOME GRAUPEL WITH ANY CONVECTIVE BASED
SHOWERS. A STRONG HIGH PRESSURE BUILDS IN TUESDAY WHICH EFFECTIVELY
ENDS ANY PRECIPITATION CHANCES. CLEARING SKIES DOES BRING WHAT WILL
LIKELY BE THE COLDEST TEMPERATURES OF THE WEEK, WITH LOWS IN THE 20S
AND HIGHS HOLDING IN THE 30S TO LOW 40S TUESDAY.
MARINE...
EASTERLY WIND INCREASES THIS MORNING AHEAD OF A DEEPENING LOW
PRESSURE SYSTEM TRACKING IN FROM THE MID-MISSISSIPPI VALLEY. 20 TO
25 KT WINDS WITH GUSTS TO 30 KT ARE FORECAST TODAY, WITH THE HIGHEST
WIND MAGNITUDE ACROSS NORTHERN LAKE HURON WHERE FETCH IS MAXIMIZED.
BRIEF GUSTS TO 35 KT GALES WILL BE POSSIBLE AT TIMES IN THIS AREA
MAINLY BETWEEN 8AM AND 2PM, BUT CONFIDENCE IS TOO LOW FOR A GALE
WARNING. SHOWERS AND THUNDERSTORMS OVERSPREAD THE AREA TODAY, SOME
OF WHICH MAY BE STRONG TO SEVERE IN THE SOUTH. AS THE CENTER OF THE
LOW REACHES THE STRAITS THIS EVENING, WIND DIRECTION VEERS AROUND TO
SOUTHWEST AND REMAINS GUSTY TO AROUND 20 TO 25 KT. STRONG COLD
ADVECTION FOLLOWS THIS SYSTEM ON SUNDAY WITH GUSTS OF 25 TO 30 KT
LIKELY THROUGH THE DAY. A GALE WATCH WAS CONSIDERED FOR NORTHERN
LAKE HURON ON SUNDAY FOR 35 KT GALES, BUT CONFIDENCE REMAINS BELOW
CRITERIA AT THIS TIME. SMALL CRAFT ADVISORIES HAVE BEEN ISSUED FOR
THE LAKE HURON NEARSHORE WATERS AND ADDITIONAL ADVISORIES ARE
POSSIBLE FOR LAKE ST. CLAIR AND WESTERN LAKE ERIE FOR SUNDAY. THE
GRADIENT RELAXES MONDAY CAUSING WIND MAGNITUDE TO WEAKEN, THEN A
SERIES OF CLIPPER SYSTEMS BRING COOLER AIR AND CHANCES FOR SNOW
SHOWERS MONDAY AND TUESDAY.
HYDROLOGY...
SEVERAL ROUNDS OF SCATTERED TO WIDESPREAD RAIN WITH EMBEDDED
ISOLATED THUNDERSTORMS CONTINUES THROUGH THE MORNING HOURS. A LULL
IN PRECIPITATION WILL BE LIKELY ACROSS SOUTHERN MICHIGAN, BEFORE A
COLD FRONT THEN BRINGS A LINE OF WIDESPREAD SHOWERS AND EMBEDDED
THUNDERSTORMS THIS AFTERNOON AND EVENING. THE TRI-CITIES AND NORTHERN
THUMB WILL EXPERIENCE LONGER RESIDENCE TIME FOR PRECIPITATION TODAY
GIVEN THE TRACK OF THE LOW PRESSURE SYSTEM. THIS BRINGS INCREASING
PROBABILITIES FOR LOCAL TOTALS TO ACHIEVE OR EXCEED 1", WITH THE
CURRENT FORECAST HIGHLIGHTING POSSIBLY TOTALS BETWEEN 1 TO 1.5"
ACROSS THE TRI-CITIES AND NORTHERN THUMB.
FOR LOCATIONS SOUTH, BASIN AVERAGES RANGE BETWEEN A HALF-INCH TO
THREE-QUARTER INCHES. HOWEVER, ANY THUNDERSTORM ACTIVITY WILL BE
CAPABLE OF PRODUCING LOCALIZED TOTAL NEARING OR EXCEEDING 1".
SEVERAL RIVER FLOOD WARNINGS ARE IN EFFECT ACROSS THE SAGINAW RIVER.
LOCALIZED FLOODING IN LOW-LYING OR FLOOD PRONE AREAS REMAIN POSSIBLE
WITH ANY THUNDERSTORM ACTIVITY.
DTX WATCHES/WARNINGS/ADVISORIES
MI...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR MIZ047-048-053>055-
060>063-068>070-075-076.
LAKE HURON...GALE WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON FOR LHZ361-
362.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT SUNDAY FOR LHZ421-441>443.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT SUNDAY FOR LHZ422.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....AA
UPDATE.......MV
DISCUSSION...AM
MARINE.......TF
HYDROLOGY....AM
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AT WWW.WEATHER.GOV/DETROIT.
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