546  
FXUS63 KDTX 310338  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
1138 PM EDT SUN MAR 30 2025  
   
KEY MESSAGES  
 
* HIGH TEMPERATURES MOSTLY IN THE 40S FOR MONDAY INTO TUESDAY BEFORE  
THE NEXT ROUND OF WARMER WEATHER WITH SHOWERS AND THUNDERSTORMS  
RETURNS WEDNESDAY.  
 
 
   
AVIATION  
 
LOW LEVEL MOISTURE WRAPPING AROUND THE DEPARTING LOW PRESSURE SYSTEM  
WILL TRAVERSE SE MI DURING THE OVERNIGHT AND INTO EARLY MONDAY  
AFTERNOON. AFTER SOME HIGH DEGREE OF VARIABILITY IN CEILING HEIGHTS  
THIS EVENING, THE MOISTURE ADVECTION COMBINED WITH COLD AIR  
ADVECTION WILL SUPPORT PREVAILING MVFR BASED CEILINGS OVERNIGHT  
THROUGH MONDAY MORNING. THERE WILL BE A VEERING OF THE WINDS TO THE  
WEST-NORTHWEST DURING THE MORNING AS MUCH COLDER AIR ADVECTS INTO  
THE AREA. SOME GUSTS AROUND 20 KNOTS ARE POSSIBLE OVERNIGHT INTO  
MONDAY MORNING AS THE COLD AIR ADVECTION DEEPENS THE LOW LEVEL MIXED  
LAYER. DRY AIR ADVECTION DURING THE COURSE OF THE AFTERNOON WILL  
SUPPORT A CLEARING TREND TOWARD MONDAY EVENING.  
   
DTW THRESHOLD PROBABILITIES  
 
* HIGH IN CEILINGS AOB 5000 FEET TONIGHT AND MONDAY.  
 
 
   
PREV DISCUSSION  
 
ISSUED AT 311 PM EDT SUN MAR 30 2025  
 
DISCUSSION...  
 
SEVERE WEATHER THREAT WINDOW REMAINS 6 TO 10 PM THIS EVENING.  
CONVECTIVE INITIATION AND ORGANIZATION UNDERWAY AS EXPECTED ACROSS  
EASTERN IL, WITHIN AN AXIS OF WEAK TO MODERATE INSTABILITY DERIVED  
WITHIN A GREATER CORRIDOR OF PRE-COLD FRONTAL CLEARING. TO THE  
EXTENT THIS CLEARING ARRIVES LOCALLY REMAINS SOMEWHAT UNCERTAIN  
GIVEN POCKETS OF CLOUD DEBRIS STILL EMBEDDED WITHIN THIS WARM  
SECTOR, BUT A NOTEWORTHY PERIOD OF LOW LEVEL MOISTURE ADVECTION  
/LOWER 60S DEWPOINTS/ AS TEMPERATURES CONTINUE TO MODERATE WILL  
CONTRIBUTE TO STEADY BOUNDARY LAYER DESTABILIZATION BY EARLY THIS  
EVENING. MLCAPE VALUES RANGING FROM 700 TO 1300 J/KG STILL PROJECTED  
BY HI RES MODEL GUIDANCE, WITH UPWARDS OF 200 J/KG ACROSS THE LOWEST  
3 KM. INBOUND ACTIVITY LIKELY TO MAINTAIN A LINEAR MODE WITH  
CLUSTERS OF HIGHER MAGNITUDE UPDRAFTS AS THE SHEAR VECTOR BECOMES  
INCREASINGLY PARALLEL TO THE GOVERNING FORCED ASCENT ALONG THE  
ADVANCING BOUNDARY. DAMAGING WIND GUST POTENTIAL HIGHLIGHTED AS THE  
GREATEST THREAT WITHIN THE EXPANSIVE SPC ENHANCED RISK UNDER THIS  
ENVIRONMENT. A TORNADO RISK DOES EXIST NOTING MAINTENANCE OF A  
SLIGHTLY VEERED PROFILE WITH HEIGHT AND ACCOMPANYING INCREASE IN  
ADEQUATE SRH. POTENTIAL EXISTS FOR THE WARM FRONT TO STALL OVER THE  
SAGINAW VALLEY AND NORTHERN THUMB, SO ANY INTERSECTION OF INCOMING  
ACTIVITY WITH THIS FEATURE COULD OFFER A HEIGHTENED RISK FOR  
UPDRAFTS TO QUICKLY ATTAIN GREATER STRUCTURE AND ROTATE.  
 
COLD FRONTAL PASSAGE BRINGS A SWIFT END TO THE CONVECTIVE THREAT BY  
02Z, WITH LINGERING POTENTIAL FOR LIGHT SHOWER PRODUCTION THROUGH  
THE LATTER HALF OF THE NIGHT AS THE TRAILING MID LEVEL TROUGH PIVOTS  
THROUGH. THIS OCCURS WITHIN A GUSTY POST-FRONTAL WEST TO NORTHWEST  
WIND, AS ENSUING COLD AIR ADVECTION INCREASES IN MAGNITUDE. PEAK  
GUSTS REACHING 30 TO 35 MPH. AIRMASS CHANGE COMPLETES HEADING INTO  
MONDAY AS LOW LEVEL THERMAL TROUGHING TAKES RESIDENCE WITHIN A  
BROADER REGION OF MID LEVEL TROUGHING. THE TIMING AND MAGNITUDE OF  
THE ADVECTIVE PROCESS WILL EFFECTIVELY MINIMIZE THE DIURNAL RECOVERY  
IN TEMPERATURE MONDAY, PLACING A CEILING FOR HIGHS AT LOW TO MID  
40S. STRETCH OF DRY AND STABLE CONDITIONS EXIST TUESDAY AS HIGH  
PRESSURE BUILDS ACROSS THE NORTHERN GREAT LAKES. FULL INSOLATION  
POTENTIAL GIVEN THE PROFILE, BUT WITH LOW LEVEL FLOW HOLDING OUT OF  
A COLD NORTHEASTERLY DIRECTION. THIS ENSURES SEASONABLY COOL  
CONDITIONS PREVAIL AGAIN TUESDAY.  
 
YET ANOTHER DYNAMIC MID LEVEL WAVE OF CENTRAL PACIFIC ORIGIN  
PROJECTED TO STRENGTHEN WHILE EJECTING NORTHEAST OUT OF THE PLAINS  
WEDNESDAY. EXPANSIVE CORRIDOR OF WARM AIR ADVECTION ALONG THE  
DOWNSTREAM FLANK WILL INITIATE DEEPER MOISTURE ADVECTION WITH THE  
NORTHWARD ADVANCING WARM FRONTAL SLOPE. INBOUND ARRIVAL SET LOCALLY  
FOR EARLY WEDNESDAY, BRINGING A GOOD CHANCE OF RAIN WITH THE  
POSSIBILITY FOR ELEVATED THUNDER GIVEN QUALITY OF THE THETA-E  
ADVECTION. STEADY LATE DAY/EVENING BOUNDARY LAYER DESTABILIZATION AS  
THE WARM SECTOR MAKES GREATER INROADS WILL LEAD TO A THERMODYNAMIC  
ENVIRONMENT NOT UNLIKE TODAY, AS TEMPS PEAK IN THE 60S AND DEWPOINTS  
APPROACH THIS MARK. GIVEN THE UNDERLYING WIND FIELD CURRENTLY  
PROJECTED, THIS AGAIN BRINGS POTENTIAL FOR A HIGHER MAGNITUDE  
CONVECTIVE EPISODE TO EMERGE ALONG AN ATTENDANT COLD FRONT/TROUGH.  
DEPENDING ON PACE AND POSITIONING OF THE FRONTAL ZONE RELATIVE TO  
THE UPPER LEVEL DYNAMICS, POSSIBILITY FOR AXIS OF HEAVY RAINFALL  
ALSO EXISTS. PREVAILING MID LEVEL SOUTHWEST FLOW LEFT BEHIND IN THE  
WAKE OF THE SYSTEM MAINTAINS MILDER CONDITIONS THROUGH THE END OF  
THE WEEK.  
 
MARINE...  
 
WARM FRONTAL BOUNDARY CURRENTLY OVER THE NORTHERN THUMB CONTINUES TO  
GRADUALLY LIFT NORTH IN RESPONSE TO LOW PRESSURE REACHING THE WESTERN  
GREAT LAKES. THE WARMER, MOIST AIRMASS BEHIND THIS FRONT IS  
SUPPORTIVE OF AREAS OF FOG DEVELOPMENT WITH WEBCAMS NEAR PORT HURON  
SHOWING PATCHY FOG POST FRONTAL PASSAGE. THIS LOW WILL DRIVE A COLD  
FRONT ACROSS THE REGION THIS EVENING AS THE LOW CENTER TRACKS  
DIRECTLY OVER LAKE HURON. A LINE OF THUNDERSTORMS LIKELY DEVELOPS IN  
ADVANCE OF THIS FRONT, TRACKING THROUGH THE CENTRAL AND SOUTHERN  
GREAT LAKES BETWEEN ROUGHLY 6PM AND MIDNIGHT. STORMS MAY BE SEVERE,  
PARTICULARLY OVER WATERS SOUTH OF PORT AUSTIN, WHERE THE MAIN HAZARD  
IS STRONG GUSTS IN EXCESS OF 34KTS AND FREQUENT LIGHTNING.  
SECONDARY, LESSER CHANCE, HAZARDS ARE HAIL AND AN ISOLATED TORNADIC  
WATERSPOUT. COLDER NORTHWEST FLOW THEN REDEVELOPS BY MONDAY  
FOLLOWING THE PASSAGE OF THE LOW/COLD FRONT TONIGHT. GIVEN THE LOW  
RAPIDLY PUSHES INTO EASTERN CANADA, A WEAKENING GRADIENT OVER THE  
CENTRAL GREAT LAKES IS EXPECTED TO KEEP NW GUSTS BELOW 30KTS. THIS  
DOES LEAD TO LARGER WAVES AROUND THE THUMB NEARSHORE WATERS WITH  
SMALL CRAFT ADVISORIES UP THROUGH TUESDAY MORNING. HIGH PRESSURE  
BUILDS OVER THE REGION FOR TUESDAY BRINGING DRIER CONDITIONS AND  
LIGHTER WINDS.  
 
HYDROLOGY...  
 
AN AREA OF SHOWERS AND THUNDERSTORMS WILL EXPAND ACROSS THE AREA  
THIS EVENING. POTENTIAL EXISTS FOR LOCALLY HEAVY RAINFALL WITHIN THE  
STRONGEST AND MOST PERSISTENT STORMS. RAINFALL TOTALS FROM ONE  
QUARTER TO ONE HALF INCH POSSIBLE. MINOR PONDING OF WATER OF PRONE  
AREAS ALONG WITH RISES ON AREA CREEKS AND STREAM ARE POSSIBLE.  
RAINFALL TAPERS OFF QUICKLY AS A COLD FRONT MOVES ACROSS THE AREA  
OVERNIGHT.  
 
 
   
DTX WATCHES/WARNINGS/ADVISORIES  
 
MI...NONE.  
LAKE HURON...SMALL CRAFT ADVISORY FROM 8 AM MONDAY TO 4 PM EDT TUESDAY FOR  
LHZ421-441.  
 
SMALL CRAFT ADVISORY FROM 2 PM MONDAY TO 4 PM EDT TUESDAY FOR  
LHZ442-443.  
 
LAKE ST CLAIR...NONE.  
MICHIGAN WATERS OF LAKE ERIE...NONE.  
 
 
 
 
AVIATION.....SC  
DISCUSSION...MR  
MARINE.......KDK  
HYDROLOGY....MR  
 
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