570
FXUS63 KDTX 291124
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
724 AM EDT SAT MAR 29 2025
KEY MESSAGES
* WELL ABOVE NORMAL TEMPERATURES HOLD THROUGH THE WEEKEND, OUTSIDE
OF THE THUMB AND SAGINAW VALLEY.
* RAIN SHOWERS INCREASE IN COVERAGE LATE TODAY THROUGH SUNDAY NIGHT.
THERE IS A SLIGHT RISK (2/5) OF SEVERE WEATHER AND POTENTIAL FOR
LOCALIZED HEAVY RAINFALL SUNDAY AFTERNOON AND EVENING.
* SEASONABLE TEMPERATURES RETURN MONDAY INTO TUESDAY BEFORE THE NEXT
ROUND OF WARMER WEATHER WITH SHOWERS AND STORMS ARRIVES WEDNESDAY
AND THURSDAY.
AVIATION
FRONTAL BOUNDARY BISECTS SOUTHEAST MICHIGAN THIS MORNING WITH COOL
NORTHERLY WINDS ON THE NORTH SIDE AND WARM SOUTHWEST WINDS ON THE
SOUTH SIDE. BULK OF WEST TO EAST TRAINING SHOWERS ARE HOLDING NORTH
OF MBS AND SHOULD STAY NORTH THROUGH THE MORNING, THOUGH A FEW STRAY
SHOWERS ARE POSSIBLE FOR PART OF THE MORNING BASED ON RADAR TRENDS.
ON THE NORTH SIDE OF THE FRONT HAS BEEN A SHALLOW MARINE LAYER AND
THE ASSOCIATED IFR CEILINGS AFFECTING MAINLY MBS MOST OF THE NIGHT,
THOUGH VISIBILITY HAVE IMPROVED TO START THIS TAF PERIOD. A FEW
HOURS OF LLWS REMAIN THIS MORNING BEFORE THE STRONG JET WINDS MOVE
EAST. THE BOUNDARY WILL LINGER AROUND THE FNT AREA WITH VFR SKIES
SOUTH OF THE FRONT. FNT WILL POSE THE MORE CHALLENGING FORECAST FOR
TODAY WITH HIGHLY VARIABLE SKIES/WINDS DEPENDING ON THE SUBTLE
MOVEMENTS IN THE FRONT. WIDESPREAD RAINFALL RETURNS THIS AFTERNOON
AND EVENING SUPPORTED BY EVEN GREATER MOISTURE LIFTING NORTHWARD.
EXPECTING MVFR TO IFR CONDITIONS ASSOCIATED WITH THIS ACTIVITY.
FOR DTW...METRO REMAINS IN THE WARM SECTOR AND UNDER THE PREDOMINATE
VFR SKIES. INCREASING SOUTHWEST WINDS WILL USHER IN GREATER LOW
LEVEL MOISTURE AND LIKELY BRING CEILINGS DOWN TO 5KFT OR BELOW BY
THIS EVENING. THUNDERSTORM CHANCES EXIST TODAY, BUT ARE TOO LOW TO
MENTION IN TAFS AT THIS TIME.
DTW THRESHOLD PROBABILITIES
* LOW IN CEILINGS AOB 5000 FEET THIS MORNING AND AFTERNOON. HIGH
THIS EVENING.
* LOW FOR THUNDERSTORMS TODAY.
PREV DISCUSSION
ISSUED AT 426 AM EDT SAT MAR 29 2025
DISCUSSION...
A STALLED FRONTAL BOUNDARY JUST SOUTH OF THE I-69 CORRIDOR BISECTS
THE AREA THIS MORNING, HELD BETWEEN COLD NORTHEAST WIND OFF LAKE
HURON AND SOUTHWEST GRADIENT WIND IN THE WARM SECTOR ACROSS THE
SOUTH. THE TEMPERATURE DIFFERENCE IS STARK WITH 30S/40S NORTH OF THE
FRONT AND MID 60S IN THE SOUTH. THE SUPPLY OF HUMID AIR INTO THE
MARINE LAYER WAS SUFFICIENT FOR A PERIOD OF DENSE FOG IN THE SAGINAW
VALLEY AND THUMB LATE LAST EVENING BEFORE STRONG OUTFLOW WIND FROM
STORMS OVER NORTHERN LOWER MI SWEPT THROUGH AND MIXED THE BOUNDARY
LAYER OUT. LATEST OBS HAVE SHOWN MAINLY 10 MI VSBY WITH LOW STRATUS
AND NO INDICATION OF IMMINENT REDEVELOPMENT OF DENSE FOG, SO HAVE
CANCELED THE ADVISORY. ADDITIONAL PATCHY FOG WILL BE POSSIBLE THIS
MORNING NEAR AND NORTH OF THE FRONTAL BOUNDARY AS IT LINGERS IN THE
SAME GENERAL AREA.
THE LLJ RESPONSIBLE FOR THE VERY MILD SOUTHWEST FLOW SOUTH OF THE
FRONT WILL CAUSE SOME GUSTINESS TO INCREASE TO AROUND 35 MPH WITHIN
THE WARM SECTOR THIS MORNING AS DAYTIME MIXING COMMENCES. THE JET
THEN VEERS AND DIMINISHES BY THIS AFTERNOON WHICH ALLOWS THE
BOUNDARY TO BEGIN TO SINK SOUTH AS A COLD FRONT, BRINGING AN
EXPANDING COVERAGE OF LOW CLOUD/FOG, COOL NORTHEAST WIND, AND
CHANCES FOR SHOWERS BY THIS EVENING. THE LOCAL TEMPERATURE GRADIENT
WILL REMAIN TIGHT AS HIGHS REACH THE LOWER 70S IN METRO DETROIT AND
SOUTH, WHILE THE NORTHERN THUMB LINGERS IN THE 40S. SO DEPENDING ON
YOUR LOCATION TODAY, CONDITIONS WILL RANGE FROM WHAT'S TYPICAL OF
EARLY MARCH TO MORE LIKE MID TO LATE MAY.
THE SURFACE FRONT'S SOUTHWARD PROGRESS CARRIES A HIGH AMOUNT OF
UNCERTAINTY AS MODELS HAVE A HARD TIME REPRESENTING AND HANDLING THE
DENSITY GRADIENT ALONG SUCH A SHALLOW FEATURE. BY TONIGHT, WARM
SECTOR SOUTHERLY FLOW GAINS A BOOST FROM LOW PRESSURE MOVING INTO
THE MIDWEST. THIS INBOUND SYSTEM WILL USHER IN A REINFORCEMENT OF
VERY MILD AND HUMID AIR WITH ORIGINS IN THE GULF - PWAT SURPASSING
1.00" AREA-WIDE AND APPROACHING 1.25" IN THE SOUTH WILL BE IN THE
90TH TO 98TH CLIMATOLOGICAL PERCENTILE. MOIST ISENTROPIC ASCENT WILL
LEAD TO EXPANDING COVERAGE OF SHOWERS THIS EVENING INTO THE
OVERNIGHT WITH THE ENVIRONMENT SUPPORTIVE OF SOME LOCALIZED POCKETS
OF HEAVIER DOWNPOURS.
MOST OF THE AREA WILL SPEND SUNDAY WITHIN THE WARM SECTOR, TEMPS
AGAIN REACHING THE 60S TO LOWER 70S, AS THE UPSTREAM LOW LIFTS INTO
THE WESTERN GREAT LAKES. COOL NORTHEAST WIND OVER LAKE HURON AND
SAGINAW BAY WILL BLOCK THE NORTHWARD FRONTAL PROGRESS, MAINTAINING A
TIGHT TEMPERATURE GRADIENT OVER THE NORTHERN SAGINAW VALLEY AND
THUMB. THE WARM ADVECTION WILL HOLD A CAP IN PLACE THROUGH THE
MORNING AND EARLY AFTERNOON WHICH FAVORS A PERIOD OF DRIER
CONDITIONS BUT CAN'T RULE OUT OCCASIONAL SHOWERS OR STORMS.
CONTINUING TO MONITOR LATE SUNDAY AFTERNOON AND EVENING FOR
POTENTIAL SEVERE THUNDERSTORMS AS OVERALL PARAMETER SPACE ADVERTISED
BY LATEST GUIDANCE (MLCAPE OF 500-1000 J/KG, EFFECTIVE WIND SHEAR OF
40 KT, AND SRH OF 100 TO 250 M2/S2) IS WELL WITHIN THE TYPICAL RANGE
OF PRIOR SEVERE EVENTS IN SE MI. THE CAP SHOWS SIGNS OF EROSION BY
LATE IN THE DAY AS LARGE SCALE ASCENT INCREASES WITH THE ARRIVAL OF
A NEGATIVELY TILTED UPPER TROUGH. LOW-LEVEL FORCING ARRIVES VIA A
STRONG 40 TO 50 KT LLJ WHILE AVAILABLE HI-RES RUNS LARGELY FAVOR
LINEAR STORM ORGANIZATION ALONG A PRE-FRONTAL TROUGH WITH EMBEDDED
ROTATING/SUPERCELLULAR STRUCTURES. THIS WILL POSE A THREAT FOR ALL
SEVERE HAZARDS INCLUDING DAMAGING WIND GUSTS, LARGE HAIL, AND
TORNADOES. SPC CONTINUES TO HIGHLIGHT THE AREA IN A SLIGHT RISK IN
THEIR LATEST DAY 2 OUTLOOK.
THE LOW TRACKS INTO LAKE HURON SUNDAY NIGHT WITH A STRONG COLD FRONT
SWEEPING ACROSS THE AREA OVERNIGHT. MOISTURE WILL QUICKLY STRIP OUT
BUT ENOUGH MAY LINGER FOR SOME A BRIEF CHANGE OVER TO SNOW SHOWERS
IN THE NORTH. OTHERWISE, HIGH PRESSURE BUILDS IN MONDAY INTO TUESDAY
WITH DAYTIME HIGHS MUCH COOLER BUT MORE SEASONABLE IN THE 40S (30S
IN THE THUMB). THE NEXT LOW PRESSURE SYSTEM IS PROGGED TO ARRIVE
INTO THE MIDWEST ON WEDNESDAY, SENDING A PLUME OF GULF MOISTURE
ACROSS THE GREAT LAKES. THIS SYSTEM WILL OFFER A HIGH LIKELIHOOD FOR
SHOWERS AND STORMS WITH POTENTIAL FOR HEAVY RAIN. WPC HAS
HIGHLIGHTED THE AREA IN A MARGINAL RISK FOR EXCESSIVE RAINFALL WHILE
SPC INCLUDED PART OF THE AREA IN A 15% SEVERE WEATHER PROBABILITY.
THESE DAY 5/6 PRODUCTS CARRY AN INHERENT AMOUNT OF UNCERTAINTY BUT
BRING ATTENTION TO OUR NEXT ACTIVE PERIOD TO MONITOR.
MARINE...
FIRST OF A SERIES OF SURFACE LOWS TRACKS ALONG THE STALLED FRONTAL
BOUNDARY, CURRENTLY RESIDING AROUND THE TIP OF THE THUMB, THIS
MORNING SHIFTING MAIN REGION OF SHOWERS BACK SOUTH FROM NORTHERN
TOWARDS CENTRAL/SOUTHERN LAKE HURON AS THE FRONTAL BOUNDARY IS
PUSHED BACK TOWARDS PORT HURON. THIS PASSAGE ALSO SHIFTS WINDS NORTH
OF THE FRONT TO MORE TRUE NORTHEASTERLY WHILE LARGELY MAINTAINING
STRENGTH- GUSTS GENERALLY 20-25KTS THOUGH NEAR POSSIBLE IN NORTH-
CENTRAL HURON GIVEN FAVORABLE FETCH OUT OF THE GEORGIAN BAY. ANOTHER
SURFACE LOW RIDES ALONG THE FRONT SUNDAY MORNING GENERATING
WIDESPREAD SHOWERS AS WELL AS INCREASING THUNDERSTORM CHANCES FOR
ALL WATERS SOUTH OF STURGEON POINT SUNDAY LATE AFTERNOON/EVENING-
THESE STORMS COULD BE STRONG TO SEVERE. FINAL SURFACE LOW LIFTING NE
OUT OF SOUTHERN WI FINALLY FORCES THE LINGERING WARM FRONT BACK TO
FAR NORTHERN LAKE HURON SETTING UP SOUTHERLY FOR THE MAJORITY OF THE
REGION LAKE SUNDAY-EARLY MONDAY. WITH THIS WARMER FLOW, WINDS LIKELY
REMAIN AT OR BELOW 25KTS. LOW VACATES THE AREA FIRST HALF OF MONDAY
SUPPORTING A TRANSITION TOWARDS SNOW AS PRECIP FINALLY TAPERS OFF IN
ADDITION TO REDEVELOPING COLDER NORTHWEST WINDS. WITH THE RAPID PACE
THIS LOW TRACKS INTO QUEBEC, THE LOCAL GRADIENT IS EXPECTED TO
WEAKEN FAST ENOUGH TO KEEP PEAK NW GUSTS SUB-GALES AT AROUND 25-
30KTS.
HYDROLOGY...
A STALLED FRONTAL BOUNDARY LINGERS ACROSS SE MI TODAY INTO TONIGHT
WITH CHANCES FOR SHOWERS EXPANDING SOUTHWARD WITH TIME. A LOW
PRESSURE SYSTEM WILL TRACK INTO THE AREA ON SUNDAY, USHERING IN
ADDITIONAL HUMIDITY WITH ORIGINS IN THE GULF. THIS ENVIRONMENT WILL
BE SUPPORTIVE OF HEAVIER SHOWERS AND STORMS TONIGHT AND PARTICULARLY
LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT AS THUNDERSTORMS INCREASE IN
COVERAGE AND INTENSITY. RAINFALL TOTALS ARE FORECAST TO RANGE
BETWEEN 0.75 AND 1.00" BUT LOCALLY HIGHER TOTALS WILL BE POSSIBLE IF
MULTIPLE STORMS TRACK OVER THE SAME LOCATIONS. THESE AMOUNTS WILL
RESULT IN MINOR PONDING AND RISES IN AREA CREEKS AND STREAMS, BUT
HIGHER IMPACT FLOODING IS NOT LIKELY AT THIS TIME.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 4 PM EDT SUNDAY FOR
LHZ421-441.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....AA
DISCUSSION...TF
MARINE.......KDK
HYDROLOGY....TF
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AT WWW.WEATHER.GOV/DETROIT.
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