786
FXUS63 KDTX 041939
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
339 PM EDT SAT APR 4 2026
KEY MESSAGES
- A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR MONROE COUNTY.
DAMAGING WIND GUSTS TO 60 MPH AND A BRIEF SPIN UP TORNADO ARE
POSSIBLE.
- A FLOOD WATCH IS IN EFFECT FOR THE MAJORITY OF SOUTHEAST MICHIGAN
AS ADDITIONAL RAINFALL FALLS ON TOP OF ONGOING MINOR FLOODING AND
RISING RIVERS.
- BELOW NORMAL TEMPERATURES SUNDAY THROUGH EARLY NEXT WEEK.
DISCUSSION
A COUPLE OF NEAR-TERM ITEMS TO NOTE, INCLUDING THE ISSUANCE OF THE
SEVERE THUNDERSTORM WATCH AND THE FLOOD WATCH. FOR THE SEVERE
WATCH... STILL LOOKING AT A SMALL GEOGRAPHIC FOOTPRINT FOR SEVERE
WEATHER AS THE NORTHERN EDGE OF A LINE OF STORMS REACHES EXTREME
SOUTHEASTERN MICHIGAN. SURFACE INSTABILITY IS STILL NOT CONVINCING
COMPARED TO COUNTIES JUST A ROW SOUTH, BUT THE MAIN CONCERN IS HOW
THE INBOUND CELLS WILL INTERACT WITH THE BOUNDARY LAYER AND THE
STRENGTH OF THE COLD POOL THAT HAS DEVELOPED. STORM MODE AND SLIGHT
BOWING LOOK TO THE INCOMING CELL LENDS TO A DAMAGING WIND THREAT IF
THESE STORMS ARE STILL SURFACE BASED. HIGHLY CONVERGENT, BACKED FLOW
AT THE CUSP OF THE MARINE LAYER IS ALSO A CONCERN FOR A BRIEF SPIN
UP TORNADO, WHICH IS BEING MONITORED CLOSELY. THERE HAS BEEN BRIEF
ROTATION OBSERVED WITH THESE CELLS. THE SEVERE WEATHER THREAT IS
MAINLY CONFINED TO MONROE COUNTY WITH STORMS ELSEWHERE REMAINING
ELEVATED (CONFIRMED BY BACKED WIND PROFILES AND TEMPERATURES STILL IN
THE 50S). THE SEVERE THREAT ENDS AS THIS LINE MOVES INTO ONTARIO,
LIKELY BY 5PM. FLOOD WATCH ISSUANCE WILL BE DISCUSSED IN THE
HYDROLOGY SECTION.
POST-FRONTAL COLD ADVECTION DROPS H8 TEMPERATURES INTO THE NEGATIVE
SINGLE DIGITS TONIGHT, ALLOWING LOWS TO FALL INTO THE MID TO UPPER
30S SUNDAY MORNING. MULTIPLE SHORTWAVE PERTURBATIONS CARVE THROUGH
THE MEAN FLOW TO REINFORCE LONGWAVE TROUGHING ACROSS EASTERN CONUS
THROUGH MID-WEEK, LEADING TO A STRETCH OF BELOW NORMAL TEMPERATURES
ACROSS THE GREAT LAKES. ONE SUCH PERTURBATION GLANCES ACROSS THE
AREA MID-DAY SUNDAY, ENGAGING REMNANT BOUNDARY LAYER MOISTURE AND
INSTABILITY TO GENERATE SCATTERED SHOWERS, POSSIBLY MIXED WITH
MELTING SNOWFLAKES AS HIGHS ONLY REACH THE LOW TO MID 40S. BREEZY
WEST WINDS (GUSTS OF 30-35 MPH) ARE ALSO EXPECTED TONIGHT-SUNDAY AS
THE PARENT LOW PEELS AWAY, ONLY GRADUALLY DRAWING ITS GRADIENT WIND
FIELD WITH IT.
UNSETTLED WEATHER PERSISTS INTO THE EARLY WEEK PERIOD AS BROAD
TROUGHING HOLDS STEADY OVERHEAD. THIS SENDS A SERIES OF PROGRESSIVE
SHORTWAVES INTO THE GREAT LAKES BETWEEN LATE SUNDAY NIGHT AND
TUESDAY MORNING. THERE IS A GLANCING SHOT FOR A RAIN-SNOW MIX EARLY
MONDAY MORNING AS THE FIRST OF THESE WAVES ARRIVES, ALTHOUGH WITH
MINIMAL IMPACTS AS MORNING LOWS ONLY BRIEFLY TOUCH FREEZING. BETTER
OPPORTUNITY FOR SNOWFLAKES TO MIX IN EXISTS WITH A SECOND WAVE
MONDAY NIGHT, BUT THIS TIME WITH STRONG COLD ADVECTION SURGING IN
BEHIND IT. COULD EVEN SEE A DUSTING OF ACCUMULATION OVER THE THUMB
WHILE TEMPERATURES PLUMMET INTO THE LOW 20S ACROSS THE STATE BY
TUESDAY MORNING. BOTH OF THESE WAVES HAVE ONLY MODEST
FORCING/MOISTURE PROSPECTS, BUT STEEP MID LEVEL LAPSE RATES (NEARLY
7.0 C/KM) COULD BRIEFLY ENHANCE RATES AT TIMES OR RESULT IN ICE
PELLETS/GRAUPEL DEVELOPMENT.
HIGH PRESSURE THEN RETURNS FOR TUESDAY INTO THE MID-WEEK PERIOD
WHILE RETURN FLOW RE-ESTABLISHES THE GULF CONNECTION FOR THE LATTER
HALF OF THE WEEK.
MARINE
BROAD LOW PRESSURE PASSES NORTHEAST ACROSS THE CENTRAL GREAT LAKES
THIS EVENING. WIDESPREAD SHOWERS WILL CONTINUE WITH EMBEDDED
THUNDERSTORMS FOCUSED MAINLY ACROSS WESTERN LAKE ERIE, LAKE ST.
CLAIR, AND SOUTHERN LAKE HURON. ISOLATED STORMS MAY BE STRONG TO
SEVERE THROUGH THIS EVENING. SOUTHEAST WIND VEERS AROUND TO
SOUTHWEST TONIGHT, INCREASING TO 15 TO 20 KT WITH GUSTS TO 25 KT AS
COLD ADVECTION ENSUES. WIND DIRECTION CONTINUES VEERING TO WESTERLY
ON SUNDAY, WITH AN UPTICK IN MAGNITUDE EXPECTED. A GALE WATCH HAS
BEEN ISSUED FOR NORTHERN LAKE HURON WITH GUSTS TO 35 KT INCREASINGLY
LIKELY THERE. ELSEWHERE, GUSTS OF 20 TO 30 KT WILL BE MORE LIKELY
BEFORE WIND DIMINISHES AND VEERS TO NORTHWEST SUNDAY NIGHT. SMALL
CRAFT ADVISORIES ARE IN EFFECT FOR THE LAKE HURON NEARSHORE WATERS
THROUGH THIS PERIOD. A CLIPPER SYSTEM PASSES THROUGH ON MONDAY WITH
AN UPTICK IN NORTHWEST WINDS EXPECTED MONDAY NIGHT IN ITS WAKE.
COOLER NORTHWEST FLOW PERSISTS INTO TUESDAY.
HYDROLOGY
RAINFALL THIS MORNING LED TO WIDESPREAD RAIN TOTALS OF 1 TO 3
INCHES, WITH ADDITIONAL RAIN MOVING IN THIS AFTERNOON AND EARLY
EVENING. REPORTS OF AREAL FLOODING AND RISES ON AREA RIVERS WILL BE
EXACERBATED BY THIS ADDITIONAL RAINFALL, WHICH MAY EXCEED ONE INCH IN
SOME LOCATIONS ESPECIALLY IN ANY THUNDERSTORMS. A FLOOD WATCH HAS
BEEN ISSUED TO ACCOUNT FOR THE WORSENING OF ONGOING FLOODING ISSUES
WITH THIS NEXT ROUND OF RAIN. SEVERAL RIVER FLOOD WARNINGS ARE IN
EFFECT AT ISSUANCE. THE HEAVY RAINFALL THREAT ENDS THIS EVENING WITH
DRIER CONDITIONS FORECAST SUNDAY THROUGH MIDDLE OF NEXT WEEK.
PREV DISCUSSION
ISSUED AT 146 PM EDT SAT APR 4 2026
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.
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.
DISCUSSION...MV
MARINE.......TF
HYDROLOGY....MV
AVIATION.....AA
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