454
FXUS63 KAPX 252343
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
743 PM EDT TUE AUG 25 2026
KEY MESSAGES
- THUNDERSTORMS LIKELY THROUGH THE DAY ON WEDNESDAY, A FEW
STRONG STORMS AND LOCALLY HEAVY RAINFALL THE MAIN CONCERNS.
DISCUSSION
ISSUED AT 110 PM EDT TUE AUG 25 2026
PATTERN SYNOPSIS AND FORECAST:
UPPER TROUGH AND INDUCED LOW PRESSURE SYSTEM WILL TRAVERSE THE UPPER
MIDWEST TONIGHT, MOVING EASTWARD WITH TIME ON WEDNESDAY INTO N MI.
PRESSURE GRADIENT INCREASES SOME WITH THE RELATIVELY "WEAK" LOW
PRESSURE SYSTEM, AND THUS BREEZY CONDITIONS ARE ANTICIPATED THROUGH
THE DAY. MAIN STORY WILL BE THE CONVECTIVE EVOLUTION AND WHAT THAT
MIGHT LOOK LIKE.
WARM ADVECTION COUPLED WITH UPPER FORCING/DIVERGENCE WITHIN AN
ENVIRONMENT CHARACTERIZED BY SUFFICIENT MOISTURE AND INSTABILITY
WILL RESULT IN SCATTERED TO NUMEROUS THUNDERSTORMS ON WEDNESDAY,
BEGINNING WEST OF 75 IN THE MORNING UP INTO THE E UP, THEN MIGRATING
AND REDEVELOPING EASTWARD DURING THE AFTERNOON HOURS. ANY STRONGER
STORM WILL BE CAPABLE OF LOCALLY GUSTY WINDS AND HAIL. ANY SEVERE
THREAT LOOKS RATHER ISOLATED AND LOCALIZED IN NATURE, GIVEN THE HIGH
MOISTURE CONTENT AND MODEST SHEAR (25 KTS OF BULK 0-6KM, LITTLE MORE
0-8KM, ALTHOUGH THAT CAN BE ENOUGH TO GENERATE TRANSIENTLY STRONG
STORMS). GIVEN TROUGH ORIENTATION/FORCING AND INSTABILITY AXIS,
NORTHEAST LOWER INTO EASTERN UPPER WILL "LIKELY" SEE THE BEST
OPPORTUNITY FOR LOCALLY HEAVY RAINFALL WITH TRAINING STORMS. THAT
BEING SAID, THE ATMOSPHERE WILL BE PRIMED WITH ~1.4"-1.5" PWATS,
SIGNIFICANT MOISTENING IN THE LOW TO MID LEVELS, AND SEEMINGLY MORE
THAN ENOUGH INSTABILITY FOR ANY STORM TO PRODUCE LOCALLY HEAVY RAIN.
GIVEN THE LOW LCLS, WEAK LOW LEVEL SHEAR, AND SUBTLE BACKING OF THE
LOW LEVEL WIND FIELD IN AREAS, AN ISOLATED TORNADO CANNOT BE
ENTIRELY RULED OUT BUT IT WILL NOT BE THE PRIMARY CONCERN. LIMITING
FACTORS WILL BE IF INSTABILITY ENDS UP BEING MUCH LESS THAN PROGGED
AND/OR IF CONVECTION WELL TO OUR NORTHWEST GENERATES A SIGNIFICANT
COLD POOL AND RUINS THE CONVECTIVE POTENTIAL FOR MOST OF NORTHERN
LOWER MI AS THE BOUNDARY IS FORCED EASTWARD QUICKER. NEVERTHELESS,
THE SIGNAL IS THERE WITHIN THE SUITE OF HI-RES GUIDANCE FOR HEAVY
RAIN IN SPOTS. LOCALIZED FLOODING NOT OUT OF THE QUESTION IF THE
INGREDIENTS COME TOGETHER JUST RIGHT. ACTIVITY DIMINISHES THROUGH
THE NIGHT WITH THE LOSS OF DAYTIME HEATING AND THE MAIN FORCING
MOVING EASTWARD.
TROUGHING CONTINUES TO DIG DOWN ACROSS ONTARIO LATE WEEK, IMPINGING
LOWER HEIGHTS ACROSS THE GREAT LAKES REGION. CONSEQUENTLY, COOLER
TEMPERATURES ARE ANTICIPATED THURSDAY INTO FRIDAY, ALTHOUGH CLOSE TO
SEASONABLE FOR THIS TIME OF YEAR. CANNOT RULE OUT SOME LIGHT SHOWERS
AS WELL DURING THIS TIME FRAME AND MILDLY BREEZY WINDS.
HEADING INTO THIS WEEKEND AND EARLY NEXT WEEK, RIDGING BUILDS ACROSS
THE SOUTH TO SOUTHEAST, TROUGHING MOVES WEST TO EAST ACROSS THE N
PLAINS AND VICINITY, AND A MORE OVERALL ZONAL STRUCTURE TAKES HOLD
FOR N MI. CONSEQUENTLY, LOW PRESSURE SYSTEM TO THE WEST WILL ADVECT
MOISTURE EASTWARD INTO THE MIDWEST, WITH ROUNDS OF RAINFALL
POSSIBLE. MOST LIKELY TIMING FOR RAIN AND STORMS WILL BE SUNDAY INTO
MONDAY AS MOISTURE ADVECTION COINCIDES WITH UPPER SUPPORT. PLENTY OF
UNCERTAINTY IN REGARDS TO THE DETAILS THOUGH. HIGH TEMPERATURES SEEM
TO HOLD STEADY IN THE UPPER 70S TO LOW 80S OUTSIDE OF THE TYPICAL
DAY TO DAY VARIABILITY GIVEN STORMS AND CLOUD COVER.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 739 PM EDT TUE AUG 25 2026
WILL START THE FORECAST CYCLE OUT VFR THIS EVENING...WITH SOME
MID/HIGH CLOUDS SPREADING IN LATER. SOME SHALLOW FOG POTENTIAL
AT KCIU/KAPN...AND ALSO SOME LOW LEVEL WIND SHEAR AFTER 0700Z
ACROSS THE NORTHERN LOWER TERMINAL. SHOWER/THUNDERSTORM COVERAGE
EXPECTED TO INCREASE FROM WEST TO EAST AFTER 0800Z...EVENTUALLY
BRINGING MVFR CONDITIONS AFTER 1200Z WITH OCCASIONAL IFR
CEILINGS/VISIBILITIES IN HEAVIER SHOWERS. MVFR CONDITIONS LIKELY
TO PREVAIL THROUGH WEDNESDAY AFTERNOON.
APX WATCHES/WARNINGS/ADVISORIES
MI...BEACH HAZARDS STATEMENT FROM 2 AM EDT WEDNESDAY THROUGH
WEDNESDAY EVENING FOR MIZ025-031.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO 10 PM EDT WEDNESDAY FOR
LHZ345.
SMALL CRAFT ADVISORY FROM 11 AM TO 10 PM EDT WEDNESDAY FOR
LHZ348-349.
SMALL CRAFT ADVISORY FROM 2 AM TO 10 PM EDT WEDNESDAY FOR
LMZ323-341-342-344>346.
DISCUSSION...JLD
AVIATION...JPB
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