987
FXUS63 KMKX 210828
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
328 AM CDT MON JUL 21 2025
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS ARE POSSIBLE FOR A PERIOD OF TIME
TUESDAY AND TUESDAY NIGHT, BUT THE TIMING IS UNCERTAIN.
- HEAT BUILDS INTO THE REGION WEDNESDAY AND THURSDAY, WITH
HIGHS IN THE LOWER 90S. HEAT INDEX VALUES OF 100 TO 107
DEGREES ARE EXPECTED ON WEDNESDAY, WITH VALUES NEAR 100
DEGREES ON THURSDAY.
- A COLD FRONT WILL SLOWLY SAG SOUTHWARD INTO CENTRAL AND
SOUTHERN WISCONSIN THURSDAY INTO FRIDAY, WITH SLIGHT CHANCES
(15-25 PERCENT) THURSDAY MORNING IN CENTRAL WISCONSIN, THEN
HIGHER CHANCES FARTHER SOUTH INTO THE REMAINDER OF SOUTHERN
WISCONSIN (50-60 PERCENT) THURSDAY AFTERNOON INTO THURSDAY
NIGHT. ADDITIONAL THUNDERSTORMS MAY LINGER THROUGH FRIDAY (20-40
PERCENT CHANCE).
SHORT TERM
ISSUED 328 AM CDT MON JUL 21 2025
TODAY THROUGH TUESDAY:
SEVERAL OBSERVATION SITES ARE INDICATING A SUBTLE REDUCTION IN
VISIBILITY WITH SMOKE AS THE OBSCURATION. THAT SHOULD DISSIPATE
AND SHIFT BACK INTO NORTHWEST WI LATE THIS MORNING, PER THE HRRR
MODEL.
SOME MID LEVEL (700MB) MOISTURE IS PRODUCING SCATTERED CLOUDS
OVER SOUTH CENTRAL WI EARLY THIS MORNING, AND THESE SHOULD
REMAIN CONFINED THERE AND SOUTHWEST OF WI TODAY. ELSEWHERE, JUST
A FEW HIGHER CLOUDS ARE EXPECTED, SO MOSTLY SUNNY SKIES IT IS. DRY
EASTERLY FLOW WILL KEEP TEMPERATURES AND DEWPOINTS IN THE
COMFORTABLE RANGE FOR SOUTHEAST WI, AND INLAND TEMPS WILL BE A
LITTLE WARMER THAN YESTERDAY WITH HIGHS IN THE LOWER 80S, WHICH
IS RIGHT AROUND NORMAL.
THE MAIN CONCERN FOR TUESDAY AND TUESDAY NIGHT IS THE CHANCE FOR
SHOWERS AND STORMS FOR SOME PERIOD OF TIME WITHIN THAT WINDOW.
THE NBM DID NOT GIVE SOUTHERN WI ANY PRECIP CHANCES, BUT I ADDED
SLIGHT CHANCE (15-24%) OF STORMS FOR MOST OF SOUTHERN WI.
SEVERAL MODELS ARE HINTING AT THE POTENTIAL FOR A THUNDERSTORM
COMPLEX TO DIMINISH AS IT APPROACHES SOUTHERN WI LATE TONIGHT,
THEN ALLOW FOR STORMS TO DEVELOP ALONG ITS OUTFLOW BOUNDARY
DURING THE DAY TUESDAY. THE ALTERNATIVE IDEA IS THAT
THUNDERSTORMS WOULD DEVELOP LATE TONIGHT OR TUESDAY MORNING OVER
NORTHERN MN AND SLIDE INTO SOUTHERN WI LATER TUESDAY AFTERNOON
OR NIGHT. HEAT AND HUMIDITY WILL BEGIN TO MOVE INTO THE AREA ON
STEADY SOUTH-SOUTHEAST WINDS TUESDAY.
CRONCE
LONG TERM
ISSUED 328 AM CDT MON JUL 21 2025
WEDNESDAY THROUGH SUNDAY:
AS HIGH PRESSURE CONTINUES TO DRIFT EASTWARD INTO THE ATLANTIC
OCEAN ON WEDNESDAY, A TROUGH OF SURFACE LOW PRESSURE EVOLVES TO
OUR NORTHWEST, SPANNING FROM NEBRASKA TO SOUTHERN MN AND NORTHERN
WI. THE RESULTING SOUTHWESTERLY BREEZE AT THE SURFACE WILL WORK
AGAINST THE LAKE BREEZE EFFECT, LIKELY SPREADING THE HEAT ALL THE
WAY EAST TO THE SHORELINE (OR CLOSE TO IT). WITH OUR CWA DEEP INTO
THE RIDGE OF THE JET BY LATE MORNING, THERE IS ONLY LITTLE HOPE
(10% CHANCE OR LESS) FOR ANY SHOWER OR STORM TO RELIEVE THE
HEAT, LEAVING US WITH MOSTLY TO COMPLETELY SUNNY SKIES, DAYTIME
HIGH TEMPS IN THE LOW 90S, AND DEWPOINTS IN THE MID 70S. THIS
SHOULD PUT HEAT INDICES INTO THE 100 TO 107 DEGREE RANGE. AS
SUCH, HEAT HEADLINES WILL LIKELY BE NEEDED ON WEDNESDAY, AND
POSSIBLY THURSDAY AS WELL.
THE AFOREMENTIONED SURFACE PRESSURE TROUGH GRADUALLY SAGS
SOUTHWARD THROUGHOUT THURSDAY, RESULTING IN GRADUALLY INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS (~50% CHANCES, CURRENTLY PEAKING
IN THE EVENING). EVAPORATIONAL COOLING AND CLOUD COVER FROM SAID
STORMS LEAVES THURSDAY'S TEMPERATURES UNCERTAIN. IF CLOUDS AND
STORMS REMAIN TO OUR NORTH THROUGH PEAK HEATING, CONTINUED
SOUTHWESTERLY WINDS AND DEWPOINTS LINGERING IN THE MID 70S COULD
ONCE AGAIN RESULT IN AREA-WIDE 100 TO 105 DEGREE HEAT INDICES. ON
THE OTHER HAND, IF STORMS ARRIVE EARLIER, TEMPERATURES COULD HOLD
BACK.
SHOWER AND THUNDERSTORM CHANCES THROTTLE BACK TO 40% INTO FRIDAY,
WITH THE LINGERING SURFACE PRESSURE TROUGH / CLOSER PROXIMITY TO
THE JET ALOFT LEADING TO CONTINUED CHANCES. BEST GUESS IS FOR
TEMPS TO HOLD IN THE MID TO UPPER 80S INTO THIS UPCOMING WEEKEND.
SHEPPARD
AVIATION
ISSUED 328 AM CDT MON JUL 21 2025
SEVERAL OBSERVATION SITES ARE INDICATING A SUBTLE REDUCTION IN
VISIBILITY (5-8SM) WITH SMOKE AS THE OBSCURATION. THAT SHOULD
DISSIPATE AND SHIFT BACK INTO NORTHWEST WI LATE THIS MORNING,
PER THE HRRR MODEL. SCATTERED MID LEVEL CLOUDS WITH BASES
AROUND 6000 FT OVER SOUTH CENTRAL WI MAY BE PRESENT AT TIMES
TODAY. EASTERLY WIND WILL PREVAIL DURING THE DAYTIME HOURS AND
DIMINISH TONIGHT. THE TYPICAL VALLEY FOG IS POSSIBLE LATE
TONIGHT.
CRONCE
MARINE
ISSUED 328 AM CDT MON JUL 21 2025
WINDS WILL CONTINUE TO SHIFT EASTERLY TODAY AS HIGH PRESSURE
EXITS TOWARD THE HUDSON BAY. WINDS WILL INCREASE TO AROUND 20
KNOTS AND BECOME SOUTHEAST ON TUESDAY AS LOW PRESSURE APPROACHES
MINNESOTA FROM THE CENTRAL PLAINS. THERE ARE CHANCES FOR STORMS
STARTING TUESDAY NIGHT AND CONTINUING THROUGH FRIDAY ALONG A
FRONTAL BOUNDARY. INITIALLY, TUESDAY NIGHT INTO THURSDAY
MORNING, EXPECT THE FRONT TO REMAIN STATIONARY ACROSS THE
NORTHERN HALF OF THE LAKE. THURSDAY AFTERNOON THROUGH FRIDAY,
EXPECT THE FRONT TO PUSH SOUTHWARD, BRINGING STORMS
SOUTHEASTWARD THROUGH THE REMAINDER OF THE OPEN WATERS. A LOW
PRESSURE TROUGH WILL DROP THROUGH THE AREA THURSDAY NIGHT INTO
FRIDAY, SHIFTING WINDS TO WESTERLY.
CRONCE
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
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