625
FXUS63 KMKX 211121
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
621 AM CDT TUE JUL 21 2026
KEY MESSAGES
- DRIER & LESS HUMID THROUGH THE END OF THE WORK WEEK. MUGGY
CONDITIONS RETURN LATE WEEKEND.
- SHOWERS & STORMS RETURN TO THE FORECAST SATURDAY INTO SUNDAY.
UPDATE
ISSUED 620 AM CDT TUE JUL 21 2026
FOR A LARGE MAJORITY OF SOUTHERN WISCONSIN THERE WILL BE DRY
WEATHER NOW THROUGH AT LEAST THURSDAY. THE SMALL CHANCE (10-20%)
FOR RAIN TODAY WILL BE ACROSS THE LAKESHORE COUNTIES. JUST
ENOUGH DIURNAL HEATING TO GET SOME INSTABILITY AND A SECONDARY
COLD FRONT COULD BE JUST ENOUGH TO GET SOME SHALLOW SHOWERS. FOR
ANYTHING THAT DOES DEVELOP, IT SHOULD BE LIGHT AND SHORT LIVED.
WINDS WILL SHIFT FROM NORTHWEST TO DUE NORTH BEHIND THIS
SECONDARY FRONT AND COOLER TEMPS ARE AHEAD. THEN HIGH PRESSURE
SHOULD SETTLE IN FOR MID WEEK. NO MAJOR CHANGES TO THE FORECAST.
PATTERSON
SHORT TERM
ISSUED 100 AM CDT TUE JUL 21 2026
TODAY THROUGH WEDNESDAY:
A COLD FRONT WILL CONTINUE SOUTHWARD ACROSS THE REGION PREDAWN
THIS MORNING, WITH GUSTY NW WINDS ARRIVING BEHIND IT POST-DAWN.
20-30 MPH GUSTS ARE EXPECTED AT TIMES THROUGH THE DAYTIME HOURS.
HIGHS IN THE LOW 80S EXPECTED. THE LATEST CAMS SUGGEST THAT A
SPRINKLE OF RAIN CANNOT BE COMPLETELY RULED OUT FROM SOME OPEN-
CELLULAR SHOWERS BENEATH THE STRONG SUBSIDENCE INVERSION, WE CAN
LIMIT THE ODDS OF ANY MEASURABLE PRECIP TO 15% OR LESS.
EVEN COOLER AND MORE PLEASANT CONDITIONS FORECAST FOR WEDNESDAY,
HIGHS IN THE 70S AND DEWPOINTS AROUND 50 (NOTICEABLY DRIER
AIR). HIGH PRESSURE PASSES DIRECTLY OVERHEAD, WITH MOSTLY SUNNY
SKIES AND DRY WEATHER.
SHEPPARD
LONG TERM
ISSUED 100 AM CDT TUE JUL 21 2026
WEDNESDAY NIGHT THROUGH SUNDAY:
SYNOPSIS: HIGH PRESSURE WILL LINGER OVER THE WESTERN GREAT LAKES
THROUGH THURSDAY, MAINTAINING A COOLER AND DRY WEATHER PATTERN. THE
HIGH WILL SHIFT EAST FRIDAY INTO SATURDAY, ALLOWING FOR SOUTHERLY
WINDS AND STEADILY CLIMBING SURFACE TEMPERATURES THROUGH THE
WEEKEND. INCREASING HUMIDITY WILL EVENTUALLY ACCOMPANY THE RISING
TEMPERATURES, THOUGH ITS ARRIVAL WILL LAG BEHIND THAT OF THE WARMER
AIR TEMPERATURES. MORE HUMID CONDITIONS WILL THUS HOLD OFF UNTIL
SATURDAY NIGHT INTO SUNDAY. WITH WARMER TEMPERATURES & HUMIDITY
ATTEMPTING TO WORK BACK INTO THE AREA, SHOWER AND THUNDERSTORM
CHANCES RETURN TO THE FORECAST SATURDAY NIGHT INTO SUNDAY.
SATURDAY THROUGH SUNDAY: THE NEXT PERIOD OF POTENTIAL WEATHER
IMPACTS ARRIVES FOLLOWING A QUIET END TO THE WORK WEEK. IMPACTS
COULD COME FROM A COMBINATION OF INCREASING HUMIDITY & HEAT INDICES
ON SUNDAY, IN ADDITION TO CHANCES FOR SHOWERS AND THUNDERSTORMS
SATURDAY NIGHT INTO SUNDAY. FINER DETAILS---NAMELY IF HEAT INDICES
WILL APPROACH HEADLINE THRESHOLDS AND/OR IF ANY STORMS COULD BE
STRONG/SEVERE---WILL BE REFINED AS TRENDS CLARIFY THROUGH THE END OF
THIS WEEK, THOUGH INITIAL INDICATIONS ARE THAT CLOUDS & LIMITED AIR
MASS RESIDENCE TIME WILL KEEP TEMPS & HEAT INDICES BELOW HEADLINE
LEVELS. ANY STRONGER STORM POTENTIAL WILL DEPEND ON TIMING, THE
DETAILS OF WHICH REMAIN MURKY THIS FAR OUT. WILL PROVIDE MORE
UPDATES AS THIS PORTION OF THE PERIOD DRAWS CLOSER.
QUIGLEY
AVIATION
ISSUED 620 AM CDT TUE JUL 21 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. LAKESHORE
TERMINALS HAVE A SMALL CHANCE (10-20%) FOR A ISOLATED SHOWER
THROUGH THE AFTERNOON. KEPT THIS OUT OF THE TAFS DUE TO THE LOW
CHANCES. OTHERWISE DIURNAL CUMULUS IS EXPECTED TO DEVELOP AROUND
4-6 KFT. BREEZY NORTHWEST TO NORTH WINDS ARE EXPECTED THROUGH
THE EVENING WITH GUSTS AROUND 25 KTS (30MPH). WINDS WILL WEAKEN
TONIGHT BECOMING LIGHT AND VARIABLE WEDNESDAY NIGHT.
PATTERSON
MARINE
ISSUED 100 AM CDT TUE JUL 21 2026
LOW PRESSURE AROUND 29.3 INCHES WILL TRACK EASTWARD ACROSS JAMES
BAY THROUGH TODAY, WITH HIGH PRESSURE OF 30.1 INCHES RESTING
OVER CENTRAL SASKATCHEWAN AND MANITOBA. WINDS WILL VEER FROM
SOUTHWEST TO NORTHWEST THROUGH THIS MORNING AND REMAIN BREEZY AS
A COLD FRONT CROSSES LAKE MICHIGAN. GUSTY NORTH WINDS THEN
ARRIVE LATE THIS AFTERNOON INTO TONIGHT, WITH A FEW GUSTS TO
GALE FORCE POSSIBLE. WINDS ARE EXPECTED TO GRADUALLY WEAKEN BY
THURSDAY, AS HIGH PRESSURE AROUND 30.2 INCHES BUILDS INTO THE
GREAT LAKES REGION.
SHEPPARD
MKX WATCHES/WARNINGS/ADVISORIES
WI...BEACH HAZARDS STATEMENT...WIZ052-WIZ060-WIZ066-WIZ071-
WIZ072...5 PM TUESDAY TO 1 PM WEDNESDAY.
LM...SMALL CRAFT ADVISORY...LMZ643-LMZ644 UNTIL 7 AM WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ645-LMZ646 UNTIL 4 PM WEDNESDAY.
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