672
FXUS63 KDTX 312231
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
631 PM EDT MON MAR 31 2025
KEY MESSAGES
* COOLER TEMPERATURES AND DRY WEATHER THROUGH TOMORROW WITH WARMER
WEATHER RETURNING WEDNESDAY INTO LATE WEEK.
* SEVERE WEATHER POTENTIAL EXISTS WEDNESDAY. THERE IS AN ENHANCED
RISK (3/5) OF SEVERE THUNDERSTORMS GENERALLY SOUTHWEST OF A FENTON
TO LIVONIA LINE, WITH A SLIGHT RISK (2/5) FOR REMAINDER OF
SOUTHEAST MICHIGAN WITH A RISK OF DAMAGING WINDS ALONG WITH A
TORNADO THREAT.
* HEAVY RAIN IS ALSO EXPECTED ON WEDNESDAY WITH TOTAL RAINFALL
AMOUNTS OF 1 TO 2 INCHES OR GREATER FROM EARLY WEDNESDAY MORNING
TO EARLY THURSDAY MORNING. A SLIGHT RISK OF EXCESSIVE RAINFALL IS
IN PLACE ACROSS WAYNE, LENAWEE, AND MONROE COUNTIES AND A MARGINAL
RISK UP TO THE I-69 CORRIDOR.
AVIATION
EXTENSIVE MVFR BASED CLOUDS HAVE REMAINED PREVALENT ACROSS SE MI
THIS AFTERNOON AS THE MOISTURE IS TRAPPED UNDER A DEEP INVERSION.
STRONG HIGH PRESSURE WILL EXPAND ACROSS THE GREAT LAKES REGION
DURING THE NIGHT. THIS WILL DRIVE MUCH DRIER AIR INTO SE MI WITHIN A
VEERING FLOW TOWARD THE NORTH. THERE HAS BEEN SOME INDICATION IN
SATELLITE DATA OF A THINNING OF THE CLOUD DECK WITH A BACK EDGE TO
THE CLEARING NOW PUSHING INTO FAR WESTERN LOWER MI. HOWEVER, GIVEN
OBSERVATIONAL TRENDS AND LATEST MODEL SOUNDINGS, THE LOW CLOUDS HAVE
BEEN EXTENDED LATER INTO THE EVENING ACROSS THE TERMINALS, WITH
CLEAR SKIES STILL EXPECTED DURING THE OVERNIGHT INTO TUESDAY
MORNING.
DTW THRESHOLD PROBABILITIES
* MODERATE IN CEILINGS AOB 5000 FEET THIS EVENING.
PREV DISCUSSION
ISSUED AT 319 PM EDT MON MAR 31 2025
DISCUSSION...
AN AREA OF HIGH PRESSURE AND DRY CONDITIONS WITH PW VALUES AROUND .15
INCHES BRING DRY WEATHER THROUGH TOMORROW AND EXTENDED PERIODS OF
SUNSHINE BY TOMORROW AS THE LAKE INFLUENCE CEASES. SOME LINGERING
CLOUD COVER WILL BE POSSIBLE NEAR THE THUMB WITH THE NORTHERLY FLOW.
TEMPERATURE HIGHS HOLD IN THE 40S TODAY AND TOMORROW IN THE WAKE OF
THE COLD FRONT.
BROADENING UPPER-LEVEL TROUGH ACROSS THE CONTINENTAL WEST WITH
EMBEDDED SHORTWAVE MAX WILL INITIATE LEE CYCLOGENESIS ACROSS THE
CENTRAL ROCKIES THROUGH THE EARLY WEEK PERIOD, WITH THE LOW PRESSURE
SYSTEM THEN TAKING ON A TRACK FROM NEBRASKA INTO WISCONSIN AS THE
TROUGH STARTS TO TAKE ON A NEGATIVE TILT. INITIAL IMPACTS ACROSS SE
MI WILL START WITH AN ARC OF LOW-LEVEL ISENTROPIC ASCENT THAT WILL
PIVOT ACROSS THE CWA LATE TUESDAY NIGHT INTO WEDNESDAY MORNING, WITH
FORECASTED SOUNDINGS HOLDING BELOW FREEZING AT ALL LEVELS, BRINGING
A CHANCE FOR SNOW. WITH THE TRANSIENT NATURE OF ELEVATED FRONTAL
SLOPES, PROJECTED SNOWFALL POTENTIAL IS DIFFICULT TO CONCRETELY
DEFINE 36-48 HOURS OUT, BUT TRACE AMOUNTS, UP TO AN INCH AND A HALF,
WILL BE POSSIBLE FROM M59 NORTH. THESE HIGHER-END TOTALS WILL BE
MORE PROBABLE ACROSS THE TRI-CITIES. FORCING BECOMES ENHANCED FROM
THE INTRUSION OF A STRONG LLJ THAT PIVOTS IN FROM SOUTH TO NORTH
THROUGH THE MID TO LATE MORNING HOURS WEDNESDAY, USHERING IN ABOVE
FREEZING TEMPERATURES IN THE LOW LEVELS, SHORTLY FOLLOWED BY ABOVE
FREEZING TEMPERATURES AT THE SURFACE. THE TIME-LAG BETWEEN H925-H50
AND THE SURFACE AFFORDS A BRIEF WINDOW FOR FREEZING DRIZZLE OR
FREEZING RAIN CHANCES BEFORE A RAPID RISE IN TEMPERATURES BY THE
AFTERNOON ENSURES RAIN AS THE P-TYPE FOR THE REMAINDER OF THE DAY.
THE IMPACTS THEN PIVOT FROM WINTER WEATHER TO CONVECTIVE AS A
PROLIFIC LLJ WILL USHER IN AN EXCEPTIONAL AMOUNT OF MOISTURE NOTED
BY H850 MOISTURE TRANSPORT MAGNITUDES NEAR 300 GM/KG, WHICH IS
CLIMATOLOGICALLY SIGNIFICANT. H850 DEW POINTS NEAR 12C WHILE PW
VALUES CHALLENGE 1.40" PW BY THE LATER AFTERNOON AND EVENING, WHICH
FALL UNDER THE 99.5TH TO OUTSIDE OF ALL CLIMATOLOGICAL BOUNDS FOR
THIS TIME OF YEAR. THIS RESULTS IN THE EXPANSION OF RAIN CHANCES
ACROSS THE ENTIRE CWA AND INTRODUCES THE CHANCE FOR ELEVATED
THUNDERSTORMS GIVEN THE BOOST IN MUCAPE AND STEEP MID-LEVEL LAPSE
RATES. SEVERE THUNDERSTORM CHANCES THEN COME INTO PLAY BY THE LATE
AFTERNOON TO WEDNESDAY NIGHT, HOWEVER, THERE REMAINS CONSIDERABLE
UNCERTAINTY REGARDING THE SURFACE-BASED CONNECTION NEEDED TO SPEAK
WITH STRONG CONFIDENCE REGARDING SEVERE COVERAGE FOR THE AFTERNOON
AND EARLY EVENING HOURS.
KINEMATICALLY, THE LLJ WILL PRODUCE LONG, PURELY STREAMWISE SR-
HODOGRAPHS THROUGH 3KM WHICH IS A CLASSIC SIGNATURE FOR SEVERE
WEATHER AND TORNADIC SUPERCELLS. HOWEVER, THE CRITICAL LIMITING
FACTOR WILL BE HOW FAR NORTH SBCAPE CAN EXTEND INTO MICHIGAN AND THE
EXTENT OF INSTABILITY. IF INSTABILITY REMAINS MAINLY ELEVATED, LOWER
PORTIONS OF THE HODOGRAPH WILL NOT BE REALIZED. ADDITIONALLY THE
AFOREMENTIONED MOISTURE WILL MAKE FOR A MUDDLED ENVIRONMENT WITH
COPIOUS CLOUD COVER AND POSSIBLY SOME DISORGANIZED SHOWERS OR EARLY
DAY CONVECTION WHICH CAN BE DECONSTRUCTIVE FOR UPSCALE GROWTH. LAST,
THIS WOULD LIKELY BE A HIGH SHEAR LOW CAPE ENVIRONMENT IF SBCAPE IS
REALIZED -- INTERNAL PROBABILISTIC DATA ONLY HAS A 50% CHANCE FOR
500 J/KG ACROSS ADRIAN, DECREASING TO A 20% CHANCE FOR 500 J/KG
ACROSS PONTIAC.
ALL BEING SAID CWASP VALUES EXCEED 60 ACROSS THE SOUTHERN THIRD OF
THE CWA, AND MACHINE LEARNING GUIDANCE IS NOTABLY AGGRESSIVE FOR A
DAY 3 OUTLOOK (PARTICULARLY FOR TORNADO AND WIND CHANCES),
SUGGESTING SURFACE BASED PARCELS CAN BE REALIZED AND INSTABILITY
MIGHT BE UNDERDONE. IF REALIZED, THE ENVIRONMENT IS PRIMED FOR
ORGANIZED CONVECTION. THE MOST LIKELY SEVERE THREAT MAY JUST BE WITH
A FRONTAL PASSAGE LATE IN THE EVENING AND NIGHT, WHICH CAN CLIP A
PORTION OF THE GREAT LAKES AND EXTENDS WELL SOUTH OF THE OHIO
VALLEY, ALIGNING WITH ML SEVERE PROBS. HI-RES GUIDANCE WILL OFFER
ADDITIONAL SUPPORT OVER THE COMING 48 HOURS. LAST, THE ENVIRONMENT
IS FAVORABLE FOR HEAVY DOWNPOURS WITH CONVECTION. LOCALIZED FLOODING
IS POSSIBLE. PLEASE SEE THE HYDROLOGY SECTION FOR ADDITIONAL
DETAILS.
HIGH PRESSURE WILL BUILD IN BEHIND THE LOW THURSDAY INTO FRIDAY,
BRINGING A WINDOW FOR DRY WEATHER. A SECOND LOW PRESSURE SYSTEM WILL
THEN SUBMERSE OF CLIP SE MI WITH ADDITIONAL RAIN AND THUNDERSTORM
CHANCES, BRINGING RENEWED CHANCES FOR HEAVY RAIN AND POSSIBLY
LOCALIZED FLOODING, PENDING THE LOCATION OF THE DEFORMATION AXIS.
MARINE...
A LOW PRESSURE SYSTEM IS RAPIDLY MOVING AWAY FROM THE EASTERN LAKES
THIS AFTERNOON WITH COLD NORTHWESTERLY FLOW ACROSS THE REGION IN ITS
WAKE. THOUGH WINDS HAVE BEEN PEAKING AROUND 25 KNOTS, THE WAVES HAVE
BUILT UP ALONG THE SHORELINE OF THE THUMB LEADING TO SMALL CRAFT
ADVISORIES IN THOSE NEARSHORE ZONES WHICH WILL LAST INTO TUESDAY
AFTERNOON. AREA OF HIGH PRESSURE WILL CENTER OVER THE STATE TUESDAY
AFTERNOON WHICH WILL ALLOW WINDS AND WAVES TO BRIEFLY SUBSIDE.
ANOTHER STRONG LOW PRESSURE SYSTEM DEVELOPS ACROSS THE MIDWEST ON
WEDNESDAY AND LEADS TO INCREASING EAST-SOUTHEASTERLY FLOW THAT WILL
HAVE POTENTIAL TO REACH GALES DURING THE DAY. THERE WILL ALSO BE
POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS ACROSS THE LAKES LATE
IN THE DAY ON WEDNESDAY.
HYDROLOGY...
WEDNESDAY CARRIES POTENTIAL FOR HEAVY RAINFALL AS A STRONG LOW
PRESSURE SYSTEM MOVES THROUGH THE MIDWEST. PWATS INCREASES TO 1.40
INCHES BY WEDNESDAY MORNING AND HOLD THERE THROUGHOUT THE DAY. THERE
WILL BE POTENTIAL FOR WIDESPREAD 1 TO 2 INCHES OF QPF OVER A 24 HOUR
PERIOD, WITH A LOW-END CHANCE FOR LOCALIZED HIGHER AMOUNTS IN EXCESS
OF 2 INCHES. THERE WILL BE TWO PEAKS IN HEAVY RAINFALL WITH THE
FIRST COMING WEDNESDAY MORNING AND THEN ANOTHER PEAK WEDNESDAY
EVENING. THERE WILL BE INCREASED FLOODING CONCERNS, ESPECIALLY IF THE
AXIS OF HEAVIER RAINFALL SETS UP OVER THE URBAN AREAS OF DETROIT.
RISES IN AREA RIVERS WILL ALSO BE LIKELY.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EDT TUESDAY FOR LHZ421-441>443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....SC
DISCUSSION...AM
MARINE.......AM
HYDROLOGY....AM
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