850
FXUS63 KDTX 242315
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
715 PM EDT THU APR 24 2025
KEY MESSAGES
- SHOWERS AND SCATTERED THUNDERSTORMS DEVELOPING TOMORROW. ISOLATED
THUNDERSTORMS MAY BE MARGINALLY SEVERE IN THE AFTERNOON.
- HIGH PRESSURE THIS WEEKEND BRINGS DRY CONDITIONS. COOL SATURDAY
BEFORE RETURNING TO NEAR NORMAL SUNDAY.
- TEMPERATURES BACK INTO THE 70S ON MONDAY BEFORE ANOTHER COLD FRONT
ARRIVES ON TUESDAY.
AVIATION
DIURNAL, HIGH BASED BOUNDARY LAYER CUMULUS WILL FADE WITH THE LOSS
OF DAYTIME HEATING. VFR CONDITIONS ARE ANTICIPATED TONIGHT WITH WIND
DIRECTIONS BECOMING EASTERLY BEHIND A BACKDOOR COLD FRONT. VFR
CONDITIONS THROUGHOUT MUCH OF FRIDAY. ABSOLUTE VORTICITY ADVECTION
AND HEIGHT FALLS AHEAD OF AMPLIFYING NORTHERN STREAM TROUGH WILL
BRING THE POTENTIAL FOR THUNDERSTORMS FRIDAY AFTERNOON. DID INCLUDE
A PREVAILING GROUP FOR -TSRA BETWEEN 21-00Z.
FOR DTW...MOST LIKELY TIMEFRAME FOR -TSRA BETWEEN 21-00Z FRIDAY.
DTW THRESHOLD PROBABILITIES
* LOW FOR CEILING AT OR BELOW 5000 FT FRIDAY.
* MODERATE FOR THUNDER LATE FRIDAY AFTERNOON/EVENING.
PREV DISCUSSION
ISSUED AT 258 PM EDT THU APR 24 2025
DISCUSSION...
ANOTHER WARM DAY TODAY WITH AN EXPANDED COVERAGE OF HIGH
TEMPERATURES REACHING 80+ DEGREES (MOST LOCATIONS ALONG/SOUTH OF I-
69). WITH WEAK FLOW IN PLACE AND DIFFERENTIAL HEATING, MARINE
INFLUENCES WILL BE A SIGNIFICANT COOLING INFLUENCE, WITH LAKE
BREEZES PUSHING FARTHER INLAND THROUGH EARLY EVENING.
POSITIVE TILTED PROGRESSIVE UPPER LEVEL TROUGH APPROACHING SOUTHERN
MANITOBA BORDER THIS AFTERNOON, SWINGING THROUGH THE CENTRAL GREAT
LAKES ON SATURDAY MORNING. OUT AHEAD OF THIS TROUGH, SOME UPPER
LEVEL ENERGY/WEAK HEIGHT FALLS EJECTS OUT OF THE MIDWEST ON FRIDAY,
SUPPORTING CYCLOGENSIS OVER SOUTHEAST MICHIGAN TOMORROW. INCREASING
LARGE SCALE ASCENT AND DESTABILIZATION WILL SUPPORT BLOSSOMING
COVERAGE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON. ML/1000-850
MB CAPES INCREASING AOA 1000 J/KG DRAWS SOME CONCERN FOR SEVERE
STORMS. THERE ARE SOME LOWER 60 DEW PTS NOTED OVER SOUTHERN INDIANA
THIS AFTERNOON WHICH WILL MAKE A RUN AT OR JUST NORTH OF THE SOUTHERN
MICHIGAN BORDER TOMORROW. HOWEVER, THE SURFACE LOW PRESSURE IS BROAD
AND THE LOW LEVEL WINDS ARE WEAK, COUPLED WITH MODEST MID LEVEL
LAPSE RATES (~6 C/KM FROM 700-500 MB). 0-6 KM BULK SHEAR ALSO
BORDERLINE SOUTH OF THE SURFACE LOW, RUNNING AROUND 30 KNOTS. ON THE
FLIP SIDE, THE SYSTEM IS RAMPING UP AS IT TRACKS THROUGH, WITH
PHASING OCCURING AS THE LOW PRESSURE SYSTEM TRACKS INTO THE EASTERN
GREAT LAKES FRIDAY NIGHT. WITH DOWNDRAFT CAPES AROUND 1000 J/KG
FRIDAY AFTERNOON, A MARGINAL/ISOLATED SEVERE THREAT SEEMS VALID WITH
PRECIP LOADED DOWNDRAFT. MARGINAL HAIL NOT OUT OF THE QUESTION AS
WELL IF ANY CELL ROTATES AND SUSTAINS THE UPDRAFT, AS MACHINE
LEARNING OUTLOOK INDICATING A 5% PROBABILITY FOR BOTH WIND AND HAIL.
GOOD SHOT OF COLD ADVECTION TO FOLLOW FOR FRIDAY NIGHT, AS 850 MB
TEMPS PROGGED TO REACH AROUND ZERO SATURDAY MORNING. WITH RATHER
TIGHT PRESSURE GRADIENT, LOCAL PROBABILISTIC GUIDANCE SUGGESTS
NORTHWEST WINDS GUSTING AROUND 30 MPH, SUPPORTED BY EURO ENSEMBLES.
SPRAWLING HIGH PRESSURE BUILDS INTO THE CENTRAL GREAT LAKES THROUGH
SUNDAY AND THEN SLIDES EAST, WITH AN ACTIVE WARM FRONT DEVELOPING
OVER THE WESTERN GREAT LAKES TO CLOSE OUT THE WEEKEND. ALL/BULK OF
ELEVATED SHOWERS EXPECTED TO STAY WEST OF THE CWA THROUGH SUNDAY
NIGHT, AS THE 700 MB JET CORE IS BACK ACROSS IOWA, PER 12Z EURO.
PRONOUNCED UPPER LEVEL RIDGE AXIS BUILDING OVER SOUTHEAST ON MONDAY
WITH 850 MB TEMPS REACHING 13 C, SUPPORTIVE OF HIGHS WELL INTO THE
70S TO NEAR 80 DEGREES ONCE AGAIN WITH SOUTHWEST FLOW RAMPING UP,
AHEAD OF A COLD FRONT ON TRACK TO MOVE THROUGH ON TUESDAY. STRONG
WIND FIELDS WITH THE AMPLIFIED NORTHERN STREAM UPPER LEVEL TROUGH
COULD PRESENT A SEVERE THREAT, BUT TIMING IS UNCERTAIN. MORNING
TIMING WOULD MITIGATE ANY SEVERE THREAT.
MARINE...
A WEAK COLD FRONT STALLS OVER THE REGION TODAY INTO TONIGHT WITH
WIND 15 KT OR BELOW FOR MOST OF THE AREA. THE EXCEPTION WILL BE
SAGINAW BAY WHERE NORTHEAST FLOW WILL QUICKLY RAMP UP TO 20 TO 25 KT
THIS AFTERNOON AND A SMALL CRAFT ADVISORY HAS BEEN ISSUED. LOW
PRESSURE LIFTS INTO THE REGION ON FRIDAY, BRINGING SCATTERED TO
NUMEROUS SHOWERS AND EMBEDDED THUNDERSTORMS ACROSS THE CENTRAL GREAT
LAKES. MODERATE EASTERLY FLOW ACROSS NORTHERN LAKE HURON BACKS TO
NORTHERLY AND SPREADS SOUTHWARD ACROSS THE LAKE AS THE LOW DEPARTS
LATE FRIDAY. N TO NNE WIND THEN PEAKS LATE FRIDAY NIGHT INTO MIDDAY
SATURDAY WITH GUSTS TO AROUND 30 KNOTS OVER CENTRAL LAKE HURON.
SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED AS WAVES BUILD ALONG
THE NEARSHORE AREAS IN THE SOUTHERN BASIN. NORTH FLOW PERSISTS
THROUGH SATURDAY BUT GRADUALLY WEAKENS AS STRONG HIGH PRESSURE
BUILDS IN FROM THE WEST. THIS HIGH PROMOTES LIGHTER WINDS AND WAVES
THROUGH SUNDAY.
HYDROLOGY...
INCREASING DAYTIME INSTABILITY AND SURFACE LOW PRESSURE ARRIVING
TOMORROW WILL SUPPORT SHOWERS AND SCATTERED THUNDERSTORMS DEVELOPING
DURING THE AFTERNOON, AS PW VALUES RISE AOA 1.25 INCHES. ALTHOUGH
BASIN AVERAGE RAINFALL IS GENERALLY EXPECTED TO BE A HALF AN INCH OR
LESS, ANY STRONG TO MARGINALLY SEVERE THUNDERSTORMS WILL PRODUCE
LOCALIZED RAINFALL OF 1.0-1.25 INCHES IN A SHORT PERIOD WHICH COULD
CAUSE MINOR URBAN AND SMALL STREAM FLOODING.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LHZ421-422.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....CB
DISCUSSION...SF
MARINE.......TF
HYDROLOGY....SF
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