865
FXUS63 KDTX 300013
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
813 PM EDT SAT MAR 29 2025
KEY MESSAGES
* WELL ABOVE NORMAL TEMPERATURES CONTINUE SUNDAY EXCEPT NOT AS WARM
NEAR SAGINAW BAY AND LAKE HURON.
* RAIN SHOWERS INCREASE COVERAGE LATE TODAY THROUGH TONIGHT WITH A
BREAK ANTICIPATED SUNDAY MORNING THROUGH ABOUT MID AFTERNOON.
* THERE IS A SLIGHT RISK (2/5) OF SEVERE THUNDERSTORMS WITH
LOCALIZED HEAVY RAINFALL ALSO POSSIBLE 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.
UPDATE
A MINOR UPDATE WAS DONE TO NUDGE POPS UP INTO THE 80 TO 100 PERCENT
RANGE GIVEN UPSTREAM RADAR RETURNS. WHILE QPF THROUGH TONIGHT WILL BE
LOW (LESS THAN 0.15 INCH) THE COVERAGE WILL BE FAIRLY WIDESPREAD.
THERE WAS ALSO SOME SLIGHT ADJUSTEMENTS TO THE HOURLY TEMPERATURES IN
LIGHT OF THE QUASI STATIONARY FRONTAL BOUNDARY BISECTING THE FORECAST
AREA. THE TIGHT THERMAL GRADIENT IS RESULTING IN A NEAR 30 DEGREE
TEMPERATURE SPREAD ACROSS SE MI.
PREV DISCUSSION
ISSUED AT 645 PM EDT SAT MAR 29 2025
AVIATION...
A QUASI STATIONARY FRONT IS LOCATED BETWEEN KFNT AND KPTK. SOME
SUBTLE SOUTHWARD MOVEMENT OF THE FRONT IS POSSIBLE THIS EVENING
BEFORE INCREASED SOUTHERLY FLOW IN THE WARM SECTOR SLOWLY PUSHES THE
FRONT NORTH OVERNIGHT AND SUNDAY MORNING. SO IF THE FRONT DOES REACH
PTK THIS EVENING, IT WILL LIKELY LIFT BACK NORTH OVERNIGHT. IFR AND
LIFR CONDITIONS WILL PREVAIL ON THE COLD SIDE OF THE FRONT, AFFECTING
MBS AND FNT INTO SUN MORNING. AN INFLUX OF MOISTURE NOW SUPPORTING
INCREASING COVERAGE OF LIGHT RAIN ACROSS SE MI WILL ALSO REDUCE CLOUD
BASES WITHIN THE WARM SECTOR DURING THE NIGHT, AFFECTING THE METRO
DETROIT TERMINALS. PROBABILISTIC GUIDANCE AND LATEST MODEL SOUNDINGS
ARE SUPPORTIVE OF CEILINGS LOWERING INTO THE IFR RANGE TOWARD
DAYBREAK SUNDAY. THERE WILL SOME IMPROVEMENT IN CEILINGS DURING THE
DAY SUNDAY, ALTHOUGH A SUBSIDENCE INVERSION IS LIKELY TO HOLD A FAIR
AMOUNT OF MVFR BASED CLOUDS THROUGH MUCH IF NOT ALL OF THE AFTERNOON.
FOR DTW...THERE IS GENERAL SUPPORT THAT LOW LEVEL MOISTURE ADVECTION
WILL DROP CEILINGS INTO THE IFR RANGE AROUND 11Z, WITH SOME
IMPROVEMENT EXPECTED AFTER 15Z AS A RESULT OF DIURNAL MIXING IN THE
WARM SECTOR. ALTHOUGH THERE IS SOME UNCERTAINTY AS TO HOW FAR NORTH
SURFACE BASED INSTABILITY WILL REACH LATE SUNDAY, ELEVATED
INSTABILITY APPEARS ENOUGH TO INTRODUCE A CHANCE OF THUNDERSTORMS
SUNDAY EVENING.
DTW THRESHOLD PROBABILITIES...
* MEDIUM IN CEILINGS AOB 5000 FEET THROUGH THIS EVENING. HIGH
OVERNIGHT THROUGH SUNDAY.
* LOW FOR THUNDERSTORMS SUNDAY EVENING.
PREV DISCUSSION...
ISSUED AT 357 PM EDT SAT MAR 29 2025
DISCUSSION...
AN ACTIVE PERIOD OF WEATHER CONTINUES THIS WEEKEND FOR THE GREAT
LAKES, FOCUSED FIRST ALONG THE STRONG FRONT STALLED ACROSS SOUTHERN
LOWER MI, AND THEN ON A STRONG LOW PRESSURE SYSTEM PROJECTED TO MOVE
INTO THE AREA LATER SUNDAY. THE RESULT IS A MORE BENIGN PATTERN OF
SHOWERS WITH A RUMBLE OF THUNDER THIS AFTERNOON AND TONIGHT WHILE
SEVERE THUNDERSTORMS REMAIN POSSIBLE WITH THE SYSTEM LATER SUNDAY
AND SUNDAY NIGHT.
THE I-69 CORRIDOR REMAINS THE BATTLEGROUND FOR THE STRONG FRONT
STALLED ACROSS THE AREA THIS AFTERNOON. TEMPERATURES SETTLED DOWN A
FEW DEGREES AS RAIN SHOWERS INCREASED OVER THE WARM SECTOR, HOWEVER
THERE IS STILL A SHORT DISTANCE GRADIENT AND ABRUPT WIND SHIFT
ACROSS THE FRONT. THE BOUNDARY IS STRENGTHENED BY GUSTY WARM SECTOR
SW WIND KEEPING TEMPERATURES IN THE 60S WHILE EQUALLY GUSTY NE WIND
IS BOOSTED BY LAKE HURON AND SAGINAW BAY ON THE COLD SIDE. CONSENSUS
OF DETERMINISTIC MODELS AND HREF MEAN SURFACE TEMPERATURE AND WIND
PROJECTIONS SUGGEST ROOM FOR SOME SOUTHWARD DRIFT OF THE FRONT WITH
SUNSET AND DECOUPLED WARM SECTOR WIND GUSTS. A NORTHWARD TREND THEN
BEGINS AS FLOW ALOFT BACKS SW AND PRIMARY SURFACE LOW PRESSURE
REACHES A SIMILAR LATITUDE LATE TONIGHT INTO SUNDAY MORNING. THIS
PROCESS ALSO ABSORBS THE CURRENT MID MS VALLEY UPPER LEVEL WAVE WHICH
ITSELF IS ENHANCING REINFORCEMENT OF GULF MOISTURE INTO THE GREAT
LAKES AND PRIMARILY RESPONSIBLE FOR THE ONGOING AND FURTHER EXPANSION
OF SHOWERS INTO LOWER MI TONIGHT. MOISTURE TRANSPORT RESULTS IN A
PRONOUNCED 850-700 MB THETA-E RIDGE IN MODEL DEPICTIONS THAT BUILDS
OVER SE MI IN TIME FOR SOME LATE NOCTURNAL ENHANCEMENT OF COVERAGE
AND INTENSITY UNTIL IT QUICKLY SHIFTS EASTWARD HEADING INTO SUNRISE.
THE RAPID PROGRESSION KEEPS 6 HR RAINFALL TOTALS MANAGEABLE AT 0.5
INCH OR LESS BEFORE ENDING EARLY IN THE MORNING.
A SUBSTANTIAL BREAK IN SHOWERS OCCURS SUNDAY MORNING INTO EARLY
AFTERNOON AS WARM SECTOR RESURGENCE TAKES PLACE ACROSS ALL OF
SOUTHERN INTO CENTRAL LOWER MI. THE BREAK IS TECHNICALLY A DRY SLOT
BETWEEN THE DEPARTING MORNING BAND OF SHOWERS AND THE MAIN LOW
PRESSURE SYSTEM MOVING INTO THE MIDWEST BY AFTERNOON AND INTO
NORTHERN LOWER MI BY SUNDAY EVENING. THE POTENTIAL FOR SEVERE
THUNDERSTORMS REMAINS THE WEATHER FOCUS FOR THIS TIME PERIOD AND IS,
AS USUAL, TIED TO THE MAGNITUDE AND DURATION OF INSTABILITY REACHING
UP INTO LOWER MI BY LATE AFTERNOON. IN THIS REGARD, IT IS NOTED THAT
HREF MEAN SURFACE BASED CAPE MATCHES UP WELL WITH HOURLY
MESOANALYSIS THIS AFTERNOON INDICATING AN AXIS OF 1000-2000 J/KG
REACHING UP INTO KS/MO, HOWEVER PROJECTIONS FAIL TO BRING THESE
VALUES INTO LOWER MI SUNDAY AFTERNOON BEFORE FADING EVEN MORE SUNDAY
EVENING. THE SPC DAY 2 OUTLOOK REFLECTS THIS WITH A MINOR SOUTHWARD
SHIFT IN THE SLIGHT RISK AREA IN SE MI, A TREND THAT COULD CONTINUE
IN LATER UPDATES. THE LOCAL FORECAST ALSO NUDGES TIMING LATER INTO
THE DAY WITH THIS UPDATE WHILE MAINTAINING POTENTIAL FOR ALL
HAZARDS. HODOGRAPHS OFF HI-RES MODEL SOUNDINGS INDICATE A MOSTLY
UNIDIRECTIONAL WIND PROFILE THAT HITS 50 KNOTS AT 500 MB BY 21Z.
DAMAGING WIND BECOMES THE PRIMARY HAZARD ASSUMING UPSTREAM STORM
INITIATION AND SOME GROWTH TOWARD A LINEAR MODE BY EARLY EVENING.
THERE IS JUST ENOUGH CURVATURE IN THE LOW LEVELS FOR A DISCRETE CELL
TORNADO RISK, ESPECIALLY IF THE SURFACE FRONT GETS HUNG UP IN THE
TRI CITIES TO NORTHERN THUMB, ASSUMING SUFFICIENT INSTABILITY CAN
MAKE IT THAT FAR NORTH UNTIL PROVEN OTHERWISE. SUB 10 KFT FREEZING
LEVEL FAVORS A HAIL RISK WITH DISCRETE STORMS BUT LIMITED BY LOWER
END MID LEVEL LAPSE RATE.
THE SURFACE LOW EXITS INTO LAKE HURON AND ONTARIO SUNDAY NIGHT AFTER
MIDNIGHT AND THE TRAILING COLD FRONT SWEEPS REMAINING SHOWERS AND
STORMS OUT OF SE MI. INBOUND COLD AIR TAKES TEMPERATURES BACK DOWN
TO AROUND NORMAL FOR APRIL 1ST, HIGHS AROUND 50 AND LOWS IN THE
UPPER 20S, ON STEADY TO SLOWLY FALLING TEMPERATURES MONDAY AFTERNOON
THROUGH TUESDAY.
MARINE...
LINGERING STALLED WARM FRONTAL BOUNDARY CURRENTLY RESIDES JUST SOUTH
OF PORT HURON LATE THIS AFTERNOON RESULTING IN LIGHTER SOUTHWEST
WINDS (15KT OR LESS) OVER THE SOUTHERN GREAT LAKES AND MODERATE
NORTHEAST WINDS (20-30KT) WINDS OVER THE BULK OF LAKE HURON. THIS
FRONTAL BOUNDARY IS GRADUALLY FORCED BACK NORTHWARD STARTING EARLY
SUNDAY MORNING AND CONTINUING THROUGH THE MAJORITY OF THE DAY AS A
FINAL, STRONGER LOW PRESSURE CENTER LIFTS ACROSS THE WESTERN GREAT
LAKES. WINDS SHIFT TO SOUTHERLY FOR ALL BUT NORTHERN LAKE HURON AS A
RESULT THOUGH GUSTS REMAIN MODEST, AROUND OR BELOW 20KTS. NE GUSTS
OVER NORTHERN LAKE HURON LIKELY ARE A BIT STRONGER, AROUND 25-30KTS,
OWING TO THE COOLER AIRMASS. SCATTERED THUNDERSTORMS BECOME POSSIBLE
BY SUNDAY AFTERNOON THOUGH GREATEST WINDOW FOR STORMS ARRIVES SUNDAY
EVENING IN ADVANCE OF THE COLD FRONT TIED TO THE AFOREMENTIONED LOW.
NUMEROUS SHOWERS AND T-STORMS ARE LIKELY DURING THE EVENING WITH
SCATTERED STRONG TO SEVERE STORMS POSSIBLE- GREATEST THREATS ARE
WIND GUSTS OVER 34KTS AND LIGHTNING WITH SECONDARY, LOWER CHANCE,
THREATS BEING HAIL AND AN ISOLATED TORNADIC WATERSPOUT (MAINLY OVER
THE SOUTHERN GREAT LAKES). SURFACE LOW TRACKS DIRECTLY OVER LAKE
HURON EARLY SUNDAY NIGHT USHERING IN COLDER NORTHWEST FLOW FOR
MONDAY. LOW RAPIDLY PUSHES INTO EASTERN CANADA RESULTING IN A
WEAKENING GRADIENT OVER THE CENTRAL GREAT LAKES WHICH IS EXPECTED TO
KEEP GUSTS SUB-GALES AND NEAR THE 25-30KT RANGE. HIGH PRESSURE THEN
BUILDS OVER THE REGION FOR TUESDAY BRINGING DRIER CONDITIONS AND
LIGHTER WINDS.
HYDROLOGY...
A STALLED FRONTAL BOUNDARY LINGERS ACROSS SE MI TONIGHT PROVIDING A
FOCUS FOR EXPANDING COVERAGE OF RAIN SHOWERS ACROSS THE AREA. A LOW
PRESSURE SYSTEM WILL MOVE IN FROM THE MIDWEST SUNDAY AFTERNOON
USHERING IN ADDITIONAL HUMIDITY WITH ORIGINS IN THE GULF. THIS
ENVIRONMENT IS SUPPORTIVE OF HEAVIER SHOWERS AND INCREASED COVERAGE
OF THUNDERSTORMS. RAINFALL TOTALS ARE FORECAST TO REACH THE 0.5 TO
1.0 INCH RANGE BUT LOCALLY HIGHER TOTALS ARE POSSIBLE IF MULTIPLE
STORMS TRACK OVER THE SAME LOCATIONS. RAINFALL OF THIS MAGNITUDE
USUALLY RESULTS IN MINOR PONDING OF WATER IN PRONE AREAS ALONG WITH
RISES IN AREA CREEKS AND STREAMS. HIGHER IMPACT FLOODING IS NOT
LIKELY AT THIS TIME.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EDT SUNDAY FOR LHZ421-441.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
UPDATE.......SC
AVIATION.....SC
DISCUSSION...BT
MARINE.......KDK
HYDROLOGY....BT
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