617
FXUS63 KDTX 280337
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1137 PM EDT MON APR 27 2026
KEY MESSAGES
- SHOWERS AND EMBEDDED THUNDERSTORMS THIS EVENING INTO EARLY
TOMORROW MORNING.
- MUCH COLDER AIR ARRIVES BY THE END OF THE WORK WEEK AND HOLDS
THROUGH THE WEEKEND.
AVIATION
SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS WILL TRACK ACROSS SE MI
DURING THE FIRST HALF OF THE OVERNIGHT. THIS IS ALL ASSOCIATED WITH
THE NORTHERN PORTIONS OF THE CONVECTIVE COMPLEX NOW AFFECTING THE
NORTHERN OHIO VALLEY. A COLD FRONT WILL BE DRIVEN EAST ACROSS SE MI
EARLY TUES MORNING. WEAK SURFACE BASED INSTABILITY ALONG THIS FRONT
WILL PROVIDE ANOTHER CHANCE FOR CONVECTION, MAINLY FOCUSED BETWEEN
08Z AND 13Z. ONGOING LOW LEVEL MOISTURE ADVECTION WITHIN THE BROAD
REGION OF SHOWERS WILL SUPPORT INCREASED PROBABILITIES FOR MVFR
BASED CLOUDS LATE TONIGHT THROUGH TUES MORNING.
D21/DTW CONVECTION...CLUSTERS OF THUNDERSTORMS ARE FORECAST TO MOVE
INTO THE D21 AIRSPACE OVERNIGHT. WITH LESS INSTABILITY FORECAST,
THERE IS THE EXPECTATION THAT THE COVERAGE WILL DECREASE AS THE
SHOWERS MOVE ACROSS THE AREA. CURRENT INDICATIONS SUGGEST THE MORE
PROBABLE CONVECTIVE TIMING WILL BE BETWEEN 08Z AND 13Z EARLY TUES
MORNING.
DTW THRESHOLD PROBABILITIES
* MODERATE FOR THUNDERSTORMS TONIGHT.
* MODERATE FOR CEILINGS AOB 5000 FEET AFTER MIDNIGHT, HIGH TUESDAY.
PREV DISCUSSION
ISSUED AT 823 PM EDT MON APR 27 2026
UPDATE...
MESO SCALE DYNAMICS ASSOCIATED WITH A WAKE LOW WHICH DEVELOPED OVER
THE WESTERN GREAT LAKES THIS AFTERNOON SUPPORTED FAIRLY WIDESPREAD
STRONG/DAMAGING WINDS ACROSS SW LOWER MI EARLIER. IT APPEARS SOME
ENHANCED SUBSIDENCE ALONG THE BACK EDGE OF A RAPIDLY DIMINISHING
REGION OF SHOWERS SUSTAINED STRONG WINDS INTO PORTIONS OF SE MI THIS
EVENING, MAINLY ACROSS THE WESTERN SECTIONS OF THE DTX FORECAST
AREA. THE SHOWERS HAVE SINCE DIMINISHED AND THE PRESSURE RISE/FALL
COUPLET HAS SIGNIFICANTLY WEAKENED. THIS HAS LARGELY ENDED THE RISK
OF ADDITIONAL WIND GUSTS OVER 40 MPH THIS EVENING.
ATTENTION NOW TURNS TO THE LARGE CONVECTIVE COMPLEX ACROSS ILLINOIS.
RECENT HI RES GUIDANCE AND REGIONAL RADAR TRENDS SUGGEST THE NORTHERN
PORTIONS OF THIS MCS WILL EXPAND INTO SE MI LATER THIS EVENING UNDER
STRONG LOW TO MID LEVEL SSW FLOW. THE 00Z DTX SOUNDING CONFIRMED A
LACK OF INSTABILITY OVER SE MI. WHILE SOME ELEVATED INSTABILITY IS
LIKELY TO ADVECT IN FROM THE SOUTHWEST, A BROAD REGION OF SHOWERS
WITH SOME EMBEDDED THUNDERSTORMS LOOKS TO BE THE MORE LIKELY OUTCOME.
MODEL SOLUTIONS AT LEAST INDICATE SOME POTENTIAL FOR WEAK SURFACE
INSTABILITY TO FILTER INTO SE MI ALONG THE ACTUAL SURFACE COLD FRONT,
FORECAST TO TRACK ACROSS THE FORECAST AREA BETWEEN 09Z AND 12Z TUES
MORNING. THIS WILL SUSTAIN A CHANCE OF CONVECTION INTO TUES MORNING.
A FORECAST UPDATE WAS ISSUED TO ADJUST EVENING WINDS AND RAIN
CHANCES BASED ON CURRENT TRENDS, OTHERWISE NO MAJOR FORECAST
ADJUSTMENTS WERE NEEDED.
PREV DISCUSSION...
ISSUED AT 305 PM EDT MON APR 27 2026
DISCUSSION...
THE TRANSITION FROM A MILD, RIDGE-DOMINATED PATTERN TO A DEEP,
UNSEASONABLY COLD REGIME REMAINS THE PRIMARY METEOROLOGICAL FOCUS AS
A MASSIVE 500MB CLOSED LOW DESCENDS FROM CENTRAL CANADA TO STALL
OVER THE GREAT LAKES BY THE END OF THE WORK WEEK. IMMEDIATE
ATTENTION CENTERS ON A ROBUST MOISTURE SURGE TONIGHT, FUELED BY A
POTENT 45-60 KT LOW-LEVEL JET (LLJ) AHEAD OF A SURFACE LOW TRACKING
TOWARD LAKE SUPERIOR. THIS SURGE WILL PUSH PWAT VALUES ABOVE 1.25
INCHES AS AN 850-700MB THETA-E RIDGE TRAVERSES SOUTHEAST MICHIGAN
AROUND 06Z TUESDAY. DESPITE THIS MOISTURE, CONVECTIVE POTENTIAL
TONIGHT WILL BE HAMPERED BY THE DIURNAL MINIMUM AND A LACK OF
SURFACE-BASED INSTABILITY, LIKELY RESULTING IN A WANING TREND FOR
SHOWERS AND ELEVATED THUNDERSTORMS AS THEY MOVE EAST. THIS IS
SUPPORTED BY LATEST HRRR AND RRFS GUIDANCE, A TREND FURTHER
SUPPORTED BY CONVECTION IN THE OHIO VALLEY EFFECTIVELY CUTTING OFF
THE DEEPER GULF MOISTURE. RAINFALL TOTALS ARE FORECAST TO AVERAGE
BETWEEN 0.20 AND 0.50 INCHES, THOUGH STEEPENING MID-LEVEL LAPSE
RATES COULD SUPPORT LOCALIZED HIGHER AMOUNTS IN MORE PERSISTENT
ELEVATED CORES. THE SEASONABLY STRONG LOW (993 MB) TRACKING THROUGH
THE WESTERN GREAT LAKES AND STRONG LOW LEVEL JET LEADS TO SOME
CONCERN WINDS COULD REACH/EXCEED 45 MPH, AS CONVECTIVELY INDUCED
RISE/FALL PRESSURE COUPLET APPROACHES, BUT UPSTREAM TRAJECTORY
SUGGESTS THE CORE STRONGEST WINDS REMAIN WEST-NORTHWEST OF SOUTHEAST
MICHIGAN. WEAKENING OF THE LINE AND ARRIVAL CLOSER TO SUNSET
EXPECTED TO KEEP GUSTS IN CHECK, BUT WILL CONTINUE TO MONITOR.
FOLLOWING A BRIEF PERIOD OF DRIER AIR BEHIND A TUESDAY MORNING COLD
FRONT, ATTENTION SHIFTS TO A DEEPENING SURFACE LOW TRIGGERED BY A
SOUTHERN-STREAM SHORTWAVE LIFTING THROUGH THE OHIO VALLEY TUESDAY
NIGHT INTO WEDNESDAY. WHILE THE BULK OF THIS SYSTEM'S MOISTURE WILL
REMAIN TO OUR SOUTH, FAVORABLE FORCING AND A SHARPENING DEFORMATION
ZONE SHOULD SPREAD RAIN SHOWERS ACROSS THE SOUTHERN AND EASTERN CWA
THROUGH WEDNESDAY AFTERNOON. AS THIS WAVE EXITS, THE 12Z ECMWF AND
CMC SHOW HIGH CONFIDENCE IN THE LARGE-SCALE POLAR TROUGH FULLY
CAPTURING THE GREAT LAKES, USHERING IN A PROLONGED PERIOD OF COLD AIR
ADVECTION WITH 850MB TEMPERATURES PLUNGING INTO THE MID TO UPPER
SINGLE DIGITS BELOW ZERO CELSIUS BY FRIDAY. THIS SETUP WILL FOSTER
STEEP LAPSE RATES AND SIGNIFICANT LAKE-INDUCED INSTABILITY, RESULTING
IN SIGNIFICANT CLOUD COVER AND "SMALL CORE" ISOLATED SHOWERS OF
RAIN, GRAUPEL, AND WET SNOWFLAKES THROUGH SATURDAY. HIGH TEMPERATURES
WILL STRUGGLE TO REACH THE LOWER 50S (10 TO 15 DEGREES BELOW EARLY
MAY NORMALS). FROST/FREEZE POTENTIAL DURING THE NIGHT TIME/EARLY
MORNING HOURS FOR THE END OF THE WORK WEEK AND WEEKEND.
MARINE...
HIGH PRESSURE INFLUENCE BREAKS DOWN TODAY AS A CLUSTER OF
THUNDERSTORMS ROLLS THROUGH THE OHIO VALLEY. MOST OF THE CONVECTIVE
ACTIVITY ASSOCIATED WITH THE MESOSCALE SYSTEM WILL WANE PRIOR TO
REACHING THE SOUTHERN WATERWAYS, BUT A FEW RUMBLES OF THUNDER CANNOT
BE RULED OUT THIS EVENING. MEANWHILE, A LOW PRESSURE SYSTEM WILL
TRACK INTO THE NORTHERN GREAT LAKES LATER THIS EVENING, CENTERED
WITHIN A POTENT/EXPANSIVE LOW-LEVEL WIND FIELD. FORECAST SOUNDINGS
ACROSS LAKE HURON REMAIN STABLE TO THE LAKE SURFACE, BUT WITH FLOW
IN EXCESS OF 40 KNOTS WITHIN THE LOWEST FEW HUNDRED FEET, OPTED FOR
A GALE WARNING FOR THE NORTHERN TWO THIRDS OF LAKE HURON. THE PERIOD
OF GALES SHOULD BE BRIEF GIVEN THE TRANSLATION SPEED OF THE PARENT
WAVE, BUT LATEST MODEL TRENDS CONTINUE TO SUPPORT MINOR INCREASES IN
CONFIDENCE FOR OCCASIONAL GUSTS TO GALES. TO FURTHER CAPITALIZE ON
THE ENERGETIC WINDS, ADDITIONAL CONVECTION IS EXPECTED AHEAD OF THE
SYSTEM'S WARM FRONT WHICH SHOULD SURGE ALL THE WAY UP TO THE
STRAITS. ELEVATED STORMS EMERGE AHEAD OF THE SURFACE BOUNDARY, AND
SHOULD AUGMENT THE STABILITY PROFILES. SMALL CRAFT ADVISORIES REMAIN
IN EFFECT FOR ALL NEARSHORE WATERS UNTIL TUESDAY DUE TO ELEVATED
WINDS/WAVES. WIND GUSTS COULD BRIEFLY APPROACH GALE-FORCE FOR
SAGINAW BAY AND MAYBE THE THUMB. THE SYSTEM'S COLD FRONT THEN
CROSSES THROUGH THE CENTRAL GREAT LAKES DURING THE DAY ON TUESDAY,
LEADING TO CALMER WEATHER AND A SHIFT TO NORTHWEST FLOW AS HIGH
PRESSURE BUILDS IN MID-WEEK.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EDT TUESDAY FOR LHZ441>443.
GALE WARNING UNTIL 8 AM EDT TUESDAY FOR LHZ361>363.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT TUESDAY FOR LHZ421-422.
LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EDT TUESDAY FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT TUESDAY FOR LEZ444.
AVIATION.....SC
UPDATE.......SC
DISCUSSION...SF
MARINE.......KGK
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