175
FXUS63 KDTX 200516
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
116 AM EDT SAT JUN 20 2026
KEY MESSAGES
- SCATTERED SHOWERS ARE POSSIBLE SATURDAY MORNING. ADDITIONAL
CHANCES SATURDAY AFTERNOON IN ADDITION TO ISOLATED THUNDERSTORM
CHANCES.
- BROADER COVERAGE OF SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY
EVENING AND OVERNIGHT, ESPECIALLY SOUTH OF I-94.
- COOLER THAN NORMAL TEMPERATURES ARE EXPECTED THROUGH AT LEAST THE
MIDDLE OF NEXT WEEK.
AVIATION
WEAK AREA OF LOW PRESSURE TRAVERSING THE REGION THIS MORNING WILL
MAINTAIN SOME POCKETS OF LIGHT SHOWER ACTIVITY WITHIN A THICKER
CANOPY OF VFR CLOUD FEATURING BASES PRIMARILY WITHIN THE 6 TO 10K FT
LEVEL. A BRIEF REDUCTION OF CEILING NEAR MVFR WILL BE PLAUSIBLE AS
ASCENT TIED TO THIS FEATURE PEAKS LATER THIS MORNING MAINLY AT MBS.
A WEAKLY UNSTABLE ENVIRONMENT WILL EMERGE IN THE WAKE AUGMENTED BY
DAYTIME HEATING. THIS WILL MAINTAIN POTENTIAL FOR ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP DURING PEAK HEATING,
WITH HIGHER PROBABILITY FROM PTK NORTHWARD BASED ON LATEST MODEL
TRENDS. BRIEF GUSTINESS UP TO 20 KNOTS TO PREVAILING WESTERLY WIND
FOR THE LATE DAY PERIOD.
D21/DTW CONVECTION... VERY LOW CHANCE OF A THUNDERSTORM LATE TONIGHT
AND AGAIN SATURDAY AFTERNOON.
DTW THRESHOLD PROBABILITIES
* LOW FOR CEILING AT OR BELOW 5 KFT LATE TONIGHT AND SATURDAY.
* VERY LOW FOR THUNDERSTORM OCCURRENCE LATE TONIGHT AND SATURDAY.
PREV DISCUSSION
ISSUED AT 247 PM EDT FRI JUN 19 2026
DISCUSSION...
HEALTHY DIURNAL CUMULUS RESPONSE TODAY AS WEAK MID-LEVEL COLD
ADVECTION HAS SUPPORTED STEEPENING LOWER LEVEL LAPSE RATES. WEAK
RESULTANT INSTABILITY (<500 J/KG) IS FOCUSED OVER THE THUMB WHERE
COOLEST AIR ALOFT RESIDES OFFERING AN ISOLATED TO WIDELY SCATTERED
SHOWER CHANCE THROUGH THE EVENING. LACK OF INSTABILITY PRECLUDES
THUNDERSTORM CHANCES HOWEVER A RUMBLE OR TWO OF THUNDER IS POSSIBLE
GIVEN FREEZING LEVELS AROUND 7KFT.
SHORTWAVE RIDGING OVERNIGHT IS SHUNTED EAST BY THE ARRIVAL OF A
COMPACT WAVE ARRIVING OUT OF THE UPPER MIDWEST LATE TONIGHT-EARLY
SATURDAY MORNING. ACCOMPANYING NOCTURNAL CONVECTION IS EXPECTED TO
AT LEAST PARTIALLY DECAY AS IT ARRIVES OVER SE MI OWING TO BOTH
UNFAVORABLE DIURNAL TIMING AS WELL AS THE LINGERING DRIER RESIDENT
AIRMASS (PW NEAR 0.6"/TD NEAR 50F). THIS AM ACTIVITY DOES AUGMENT
THE COLUMN MOISTURE PROFILE AS TOP-DOWN SATURATION OCCURS BY LATE
MORNING SUPPORTING AFTERNOON CONVECTIVE POTENTIAL AS A PEAK OF
~500J/KG OF MLCAPE DEVELOPS. GREATEST CHANCES FOR CONVECTIVE SHOWERS
AND PERHAPS A THUNDERSTORM CONTINUE TO LOOK FAVORED OVER THE SAGINAW
VALLEY/THUMB WHERE THE FAINT SURFACE 'WARM FRONT' STALLS PROVIDING A
WEAK CONVERGENCE AXIS IN ADDITION TO CLOSER PROXIMITY TO THE PARENT
PV ANOMALY.
ANOTHER BRIEF PERIOD OF LOW AMPLITUDE MID-LEVEL RIDGING FOLLOWS
SATURDAY NIGHT INTO SUNDAY MORNING BEFORE A PLAINS SHORTWAVE EJECTS
INTO THE OHIO VALLEY LATE SUNDAY. MID-RANGE MODEL TRENDS HAVE HELD
WITH A MORE SOUTHERLY TRACK IN THE WAVE RESULTING IN THE ATTENDANT
WARM FRONT HOLDING NEAR OR JUST SOUTH OF THE STATE LINE. GIVEN
NORTHERLY FLOW OVER LOWER MI FROM NORTHERN ONTARIO HIGH PRESSURE,
EXPECT A SHARPER CUTOFF TO THE PRECIP SHIELD THAN THE CURRENT BROAD
BRUSHED LIKELY POPS FROM THE NBM. AREAS SOUTH OF M-59 STAND THE BEST
CHANCES TO SEE SHOWERS SUNDAY NIGHT-MONDAY MORNING WITH HEAVIEST
RAINFALL TOTALS (AROUND 1") CONFINED TO NEAR THE OHIO BORDER.
THERMAL TROUGHING CONTINUES TO HOLD OVER THE GREAT LAKES THROUGH
MIDWEEK MAINTAINING SEASONALLY COOL CONDITIONS WITH HIGHS IN THE
LOWER 70S AND LOWS IN THE LOWER 50S. NEXT CHANCES FOR SHOWERS AND
THUNDERSTORMS COME WEDNESDAY WITH THE ARRIVAL OF A WEAK UPPER
MIDWEST SHORTWAVE.
MARINE...
A RIDGE OF HIGH PRESSURE WILL BUILD IN TONIGHT THROUGH TOMORROW
MORNING WHICH WILL DIMINISH WIND SPEEDS AND GUST INTENSITY
OVERNIGHT. A DIFFUSE AREA OF HIGH PRESSURE WILL THEN HOLD OVER THE
GREAT LAKES THROUGH THE WEEKEND WHICH WILL SUPPORT LIGHTER WINDS.
PERIODIC RAIN SHOWERS WILL BE POSSIBLE AS MULTIPLE UPPER-LEVEL
DISTURBANCES MOVE OVER THE REGION. A LOW PRESSURE SYSTEM WILL THEN
ARRIVE OVER THE OHIO VALLEY AND SOUTHERN GREAT LAKES SUNDAY NIGHT TO
MONDAY MORNING, THIS WILL BRING THE NEXT LIKELY CHANCES FOR RAIN AND
SOME EMBEDDED THUNDERSTORMS AND SOME STRONGER WIND GUSTS, MAINLY
ACROSS LAKE ERIE AND LAKE ST. CLAIR.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....MR
DISCUSSION...KDK
MARINE.......AM
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page