029
FXUS63 KDTX 040402
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1202 AM EDT SAT APR 4 2026
KEY MESSAGES
- WIDESPREAD SHOWERS AND SOME EMBEDDED THUNDERSTORMS DEVELOP LATE
TONIGHT AND CONTINUE THROUGH MOST OF SATURDAY.
- THUNDERSTORMS MAY BE STRONG ON SATURDAY, PRODUCING WIND GUSTS OF
45 TO 55 MPH, PARTICULARLY OVER THE EASTERN HALF OF THE CWA, WHERE A
MARGINAL SEVERE RISK ALSO EXISTS.
- BELOW-NORMAL TEMPERATURES RETURN SUNDAY AND PERSIST THROUGH EARLY
NEXT WEEK. LOW TEMPERATURES IN THE 20S ARE LIKELY BOTH MONDAY NIGHT
AND TUESDAY NIGHT.
AVIATION
CONVECTION IS STARTING TO SPREAD NORTH OF THE STATE LINE AS OF 04Z,
AND SHOULD CONTINUE TO FILL IN AND EXPAND IN COVERAGE WHILE THE
FORCING WORKS NORTHWARD EARLY IN THE FORECAST FOR A FEW HOURS.
SCATTERED SHOWERS ARE STILL POSSIBLE THROUGH THE EARLY MORNING,
THOUGH CONFIDENCE IS LOWER THAT THEY WILL REMAIN WIDESPREAD ENOUGH
ACROSS DETROIT TO REMAIN IMPACTFUL. MBS AND FNT WILL BE UNDER THE
ELEVATED FRONT THROUGH MID MI LONGER TODAY WHICH COULD KEEP THEM
EMBEDDED IN SHOWERS EARLY SATURDAY MORNING THROUGH THE AFTERNOON
COLD FRONTAL PASSAGE. IFR CIGS FOR SEVERAL HOURS IN THE MORNING
AFTERNOON SHOULD GET WASHED OUT WITH THE SECOND MAIN BAND OF SHOWERS
AND STORMS IN THE AFTERNOON. THESE STORMS COULD BE STRONG TO SEVERE.
EASTERLY WINDS TONIGHT WILL FLIP TO THE SOUTHWEST TOMORROW AHEAD OF
THE COLD FRONT AND EVENTUALLY WESTERLY LATER IN THE AFTERNOON BEHIND
THE COLD FRONT.
FOR DTW...TWO MAIN WINDOWS FOR CONVECTION TO WATCH. THE FIRST WILL
BE OVERNIGHT FROM 05-09Z AS A WARM FRONT LIFTS NORTH. THERE IS A
CHANCE FOR SMALL HAIL, BUT SEVERE WEATHER IS NOT EXPECTED. AFTER A
POTENTIAL LULL IN ACTIVITY IN THE LATE MORNING/EARLY AFTERNOON THE
COLD FRONTAL BAND OF STORMS WILL PASS EASTWARD FROM ABOUT 17-21Z.
THESE STORMS COULD REACH SEVERE LIMITS AS WE LIE ON THE EXTREME
WESTERN EDGE OF THE SLIGHT RISK AREA.
DTW THRESHOLD PROBABILITIES
* HIGH FOR CEILING AT OR BELOW 5000 FT TONIGHT AND SATURDAY.
* MODERATE FOR THUNDERSTORMS OVERNIGHT. MODERATE SATURDAY
AFTERNOON.
PREV DISCUSSION
ISSUED AT 250 PM EDT FRI APR 3 2026
DISCUSSION...
A STRONG, CLOSED 500MB LOW IS TRACKING THROUGH THE CENTRAL/NORTHERN
PLAINS THIS EVENING AND WILL MOVE THROUGH THE WESTERN GREAT LAKES
TOMORROW. AN EXCEPTIONAL 500 MB HEIGHT FALL CENTER IS SET TO TRACK
THROUGH SOUTHERN MINNESOTA SATURDAY MORNING AND THROUGH LAKE
SUPERIOR SATURDAY EVENING. A STRONG SOUTHWEST LOW-LEVEL JET (LLJ) OF
50 - 60 KNOTS WILL TRACK THROUGH THE WESTERN OHIO VALLEY AND
SOUTHEAST MICHIGAN SATURDAY MORNING. STELLAR MOISTURE ADVECTION WILL
TAKE PLACE TONIGHT, WITH PRECIPITABLE WATER (PW) VALUES RISING TO AT
OR ABOVE 1.3 INCHES- A RECORD-SETTING LEVEL FOR EARLY APRIL PER THE
SPC SOUNDING CLIMATOLOGY. FORTUNATELY, INSTABILITY WILL BE WEAK;
MUCAPE WILL STRUGGLE TO REACH 300 J/KG AND WILL BE MOSTLY CONFINED TO
NEAR THE SOUTHERN MICHIGAN BORDER TONIGHT. FURTHERMORE, WITH MID-
LEVEL LAPSE RATES BEING AVERAGE TO POOR, SEVERE HAIL LOOKS UNLIKELY.
THERE ARE NO CONCERNS FOR SEVERE WIND TONIGHT DUE TO A STEEP LOW-
LEVEL INVERSION AND BACKED SURFACE FLOW FROM THE SOUTHEAST.
WITH THE SURFACE LOW TRACKING OVER EASTERN IOWA AND INTO SOUTHERN
WISCONSIN TONIGHT, THE BEST FORCING LOOKS TO RESIDE OVER WESTERN
LOWER MICHIGAN, WHERE THE HEAVIEST RAINFALL TOTALS ARE EXPECTED. THE
PERSISTENT NEAR-SURFACE INVERSION WILL BE MAINTAINED BY A
COMBINATION OF EARLY-MORNING RAIN AND THICK CLOUD COVER AS THE
OCCLUSION RESIDES OVER SOUTHEAST MICHIGAN FOR MOST OF THE DAY. THERE
APPEARS TO BE A SHORT WINDOW DURING THE AFTERNOON- DEPENDING ON THE
TRACK AND INTENSITY OF THE LOW THROUGH NORTHERN LOWER
MICHIGAN- WHERE EASTERN AREAS COULD ENTER A MUDDLED WARM SECTOR
BEFORE THE COLD FRONT SWINGS THROUGH BY EARLY EVENING. STRONG WIND
FIELDS (50 KNOTS AT 850 MB) COULD STILL SUPPORT A MARGINAL WIND
THREAT DESPITE WEAK SURFACE-BASED INSTABILITY. WE MAY SEE CONVECTIVE
SHOWERS PRODUCE STRONGER WIND GUSTS OF 45 TO 55 MPH, WITH EVEN
GRADIENT WINDS POTENTIALLY APPROACHING 45 MPH LATE IN THE DAY. THE
EASTERN HALF OF THE CWA STANDS THE BEST CHANCE FOR STRONGER WINDS DUE
TO THE TIMING OF THE COLD FRONT DURING PEAK HEATING. IN FACT, SPC
EVEN UPGRADED AREAS ALONG A LINE FROM MONROE-DETROIT-PORT HURON TO
SLIGHT RISK OF SEVERE, INCLUDING 2 PERCENT FOR TORNADO. HOWEVER,
EXPECT THE MOST FAVORABLE OVERLAP OF BUOYANCY AND WIND SHEAR SHIFTING
EAST INTO LAKE ERIE BASIN AND SOUTHWESTERN ONTARIO BY THE TIME PEAK
HEATING OCCURS.
SUNDAY THROUGH TUESDAY: THE DEPARTURE OF THE LOW-PRESSURE SYSTEM
INTO EASTERN CANADA WILL USHER IN A PERIOD OF STRONG COLD-AIR
ADVECTION AS FLOW VEERS TO THE NORTHWEST. H850 TEMPERATURES ARE
PROGGED TO DROP SIGNIFICANTLY, FALLING INTO THE -6°C TO -10°C RANGE
BY SUNDAY MORNING. THIS WILL RESULT IN A SHARP CONTRAST FROM
SATURDAY'S WARMTH, WITH SURFACE HIGHS STRUGGLING TO EXIT THE MID-40S
UNDER PERSISTENT CYCLONIC FLOW AND STRATOCUMULUS COVER. MODEL
CONSENSUS, INCLUDING THE ECMWF AND CANADIAN, HIGHLIGHTS A REINFORCING
THERMAL TROUGH AS A SECONDARY SHORTWAVE CARVES INTO THE LONGWAVE
TROUGH OVER THE GREAT LAKES MONDAY INTO TUESDAY. GIVEN THE LOW
FREEZING LEVELS (GENERALLY BELOW 1,500 FT AGL) AND STEEP LAPSE RATES,
ANY CONVECTIVE- BASED SHOWERS ON MONDAY COULD PRODUCE A RAIN/SNOW
MIX OR EVEN GRAUPEL, DESPITE SURFACE TEMPERATURES IN THE 40S. BY LATE
TUESDAY, A STRONG 1030+ MB SURFACE HIGH IS EXPECTED TO BUILD INTO
THE REGION, FINALLY SCOURING OUT THE LINGERING CLOUD COVER. LOW
TEMPERATURES IN THE 20S APPEAR LIKELY FOR BOTH MONDAY NIGHT AND
TUESDAY NIGHT.
MARINE...
A SHORT-LIVED RIDGE OF HIGH PRESSURE PASSES OVER THE GREAT LAKES
THIS EVENING IN BETWEEN LOW PRESSURE SYSTEMS, ALLOWING GUSTY
WESTERLY WINDS TO SUBSIDE AND VEER AROUND TO EASTERLY BY SATURDAY
MORNING. THE NEXT LOW TRACKS FROM THE MID-MISSISSIPPI VALLEY TO
ACROSS THE STRAITS BY SATURDAY EVENING, BRINGING WIDESPREAD SHOWERS
AND THUNDERSTORMS TONIGHT INTO TOMORROW, SOME OF WHICH COULD BE
STRONG TO SEVERE IN THE SOUTH. A TIGHTENED PRESSURE GRADIENT
PRODUCES EASTERLY WIND GUSTS TO 30 KNOTS ACROSS NORTHERN LAKE HURON
LATE TONIGHT INTO SATURDAY AFTERNOON. THERE IS POTENTIAL FOR BRIEF
GUSTS TO 35 KNOT GALES, MAINLY BETWEEN 8AM AND 2PM, BUT CONFIDENCE
IS TOO LOW FOR A GALE WARNING AT THIS TIME. AS THE SYSTEM LIFTS
NORTH OF LAKE HURON LATE SATURDAY, WIND WILL VEER AROUND TO
SOUTHWEST AND BECOME GUSTY AS COLD ADVECTION ENSUES SATURDAY NIGHT.
GUSTS OF 25 TO 30 KT CAN BE EXPECTED THROUGH SUNDAY AND SMALL CRAFT
ADVISORIES WILL BE LIKELY. THE GRADIENT RELAXES MONDAY CAUSING WIND
MAGNITUDE TO WEAKEN. A SERIES OF CLIPPER SYSTEMS BRING COOLER AIR
AND CHANCES FOR SNOW SHOWERS MONDAY AND TUESDAY.
HYDROLOGY...
THE INFLUX OF HIGH MOISTURE CONTENT, CHARACTERIZED BY PW VALUES NEAR
1.30 INCHES, WILL SUPPORT HIGH PRECIPITATION EFFICIENCY ACROSS
SOUTHEAST MICHIGAN TONIGHT THROUGH SATURDAY EVENING. A WIDESPREAD
AREA OF RAIN, OCCASIONALLY ENHANCED BY EMBEDDED THUNDERSTORMS, IS
EXPECTED TO BRING BASIN-AVERAGE RAINFALL TOTALS OF APPROXIMATELY
0.75 INCHES TO MOST OF THE REGION. HOWEVER, GIVEN THE ROBUST LOW-
LEVEL JET AND STRONG MOISTURE CONVERGENCE, ANY STRONGER CONVECTIVE
ELEMENTS OR TRAINING OF CELLS COULD LEAD TO HIGHER LOCALIZED
AMOUNTS. IN THESE AREAS, RAINFALL TOTALS HAVE THE POTENTIAL TO REACH
OR EXCEED 1.5 INCHES.
FORTUNATELY, CURRENT 6-HOUR FLASH FLOOD GUIDANCE (FFG) FOR THE
SAGINAW VALLEY AND THE BROADER CWA REMAINS GENERALLY AT OR ABOVE 2.0
INCHES. THIS INDICATES THE SOIL AND DRAINAGE SYSTEMS SHOULD BE ABLE
TO ABSORB THE ANTICIPATED RAINFALL WITHOUT SIGNIFICANT FLASH
FLOODING. PRIMARY IMPACTS WILL LIKELY BE LIMITED TO NUISANCE PONDING
OR MINOR FLOODING IN URBAN OR LOW-LYING AREAS AND STEADY, NEAR-
BANKFULL RISES ON LOCAL RIVERS THROUGH THE REMAINDER OF THE WEEKEND,
WITH A LOW POTENTIAL TO REACH FLOOD STAGE.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 4 AM EARLY THIS MORNING TO 10 PM EDT
SUNDAY FOR LHZ421-441.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 10 PM EDT SUNDAY
FOR LHZ422.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 10 PM EDT SUNDAY
FOR LHZ442-443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....DRK
DISCUSSION...SF
MARINE.......TF
HYDROLOGY....SF
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AT WWW.WEATHER.GOV/DETROIT.
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