599
FXUS63 KMKX 210337
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1037 PM CDT SUN JUL 20 2025
KEY MESSAGES
- A BROKEN LINE OF STORMS WILL PROGRESS ACROSS NORTHERN AND
CENTRAL WISCONSIN TUESDAY NIGHT, WITH THE BEST CHANCES ACROSS
NORTHERN WISCONSIN.
- HEAT BUILDS BACK INTO THE REGION WEDNESDAY AND THURSDAY, WITH
HIGHS IN THE LOWER 90S. HEAT INDEX VALUES OF 100 TO 105
DEGREES ARE EXPECTED ON WEDNESDAY, WITH VALUES NEAR 100
DEGREES ON THURSDAY.
- A COLD FRONT WILL SLOWLY SAG SOUTHWARD INTO CENTRAL AND
SOUTHERN WISCONSIN WEDNESDAY NIGHT INTO FRIDAY, WITH SLIGHT
CHANCES (15-25 PERCENT) ON WEDNESDAY NIGHT TO THURSDAY MORNING
IN CENTRAL WISCONSIN, THEN HIGHER CHANCES FARTHER SOUTH INTO
THE REMAINDER OF SOUTHERN WISCONSIN (30-50 PERCENT) THURSDAY
AFTERNOON INTO THURSDAY NIGHT. ADDITIONAL THUNDERSTORMS MAY
LINGER THROUGH FRIDAY (30-40 PERCENT CHANCE).
UPDATE
ISSUED 1035 PM CDT SUN JUL 20 2025
NO CHANGES TO THE GOING FORECAST AT THIS TIME.
SHEPPARD
SHORT TERM
ISSUED 312 PM CDT SUN JUL 20 2025
TONIGHT THROUGH MONDAY NIGHT:
CLOUDS WILL SCATTER OUT INTO TONIGHT, WITH NORTHEASTERLY BREEZES
CONTINUING. EXPECT LOWS IN THE UPPER 50S TO LOWER 60S. WILDFIRE
SMOKE WILL MOVE IN ALOFT TONIGHT AS WELL, MIXING DOWN TO THE
SURFACE IN SOME AREAS AND REDUCING VISIBILITIES. WILDFIRE SMOKE
WILL SCRUB BACK OUT OF THE AREA ON MONDAY AS WINDS SHIFT
SOUTHEASTERLY.
SOUTHEASTERLY WINDS AND SUNSHINE WILL BRING A RETURN TO HIGHS IN
THE LOWER 80S ON MONDAY, BUT LAKESIDE COUNTIES WILL REMAIN IN
THE UPPER 70S WITH FLOW OFF LAKE MICHIGAN. A RETURN TO WAA AND
SOUTHEASTERLY FLOW DUE TO THE LOW DEVELOPING IN THE LEE OF THE
COLORADO ROCKIES WILL ALLOW FOR A DIFFUSE FRONTAL FEATURE TO
DEVELOP ACROSS THE NORTHERN PLAINS INTO MINNESOTA AND PERHAPS AS
FAR EAST AS NORTHERN WISCONSIN.
OVERNIGHT MONDAY, EXPECTING CONVECTION TO REMAIN TO THE WEST AND
NORTH (SOUTHERN WISCONSIN REMAINS DRY). A FEW OUTLIER CAMS ARE
SHOWING AN UNZIPPING FEATURE FROM NORTHERN WISCONSIN THROUGH
SOUTHWESTERN WISCONSIN, BUT THE FORCING IS LACKING. THE BEST
UPPER LEVEL DYNAMICS (200 MB JET) REMAINS NORTH OF THE CANADIAN
BORDER, WITH THE LLJ POINTED ONCE AGAIN INTO SOUTHERN IOWA.
ALTHOUGH AN ISOLATED SHOWER COULD DEVELOP, SYNOPTIC SCALE
FORCING DOES NOT SUPPORT MCS MAINTENANCE INTO SOUTHERN WISCONSIN
AT THIS TIME. EXPECTING LOWS IN THE MID-60S.
THERE IS A MODERATE SWIM RISK FOR BEACHES IN RACINE AND KENOSHA
COUNTIES INTO THIS EVENING. BREAKING WAVES AND CURRENTS ARE
EXPECTED. STAY AWAY FROM DANGEROUS AREAS LIKE PIERS, BREAKWALLS,
AND RIVER OUTLETS. A MODERATE SWIM RISK MAY ALSO DEVELOP FOR
LAKE MICHIGAN BEACHES IN SHEBOYGAN AND OZAUKEE COUNTIES EARLY
TUESDAY MORNING, CONTINUING THROUGH TUESDAY AFTERNOON.
MH
LONG TERM
ISSUED 312 PM CDT SUN JUL 20 2025
TUESDAY THROUGH SUNDAY:
DRY CONDITIONS LINGER INTO TUESDAY AS STRONG RIDGING BUILDS OVER
THE AREA FROM THE SOUTHEAST U.S., WITH BREEZY SOUTHERLY WINDS
BRINGING HOT AND HUMID CONDITIONS BACK TO SOUTHERN WISCONSIN.
EXPECT HEAT INDEX VALUES TO RISE INTO THE LOWER 90S AWAY FROM
LAKE MICHIGAN (A SLIGHT EASTERLY/ONSHORE COMPONENT WILL KEEP
THOSE AREAS IN THE 80S). PLENTY OF MOISTURE MAY RESULT IN A FEW
POP-UP THUNDERSTORMS, BUT FORCING IS WEAK SO ANYTHING THAT DOES
DEVELOP WILL REMAIN ISOLATED.
OVERNIGHT TUESDAY, MODELING DEPICTS MULTIPLE SHORTWAVES
POTENTIALLY TRAVERSING EASTWARD THROUGH NORTHERN WISCONSIN,
BRINGING A FEW SCATTERED THUNDERSTORMS TO CENTRAL WISCONSIN
(15-20 PERCENT CHANCE), BUT TRENDS ARE FARTHER NORTHWARD AND THE
MAJORITY OF SOUTHERN WISCONSIN SHOULD REMAIN DRY.
WEDNESDAY, RIDGING CONTINUES TO BUILD, WITH THE HIGHEST
TEMPERATURES OF THE WEEK EXPECTED UNDER A RIDGE OF HIGH
PRESSURE. SOUTHWESTERLY WINDS WILL ALLOW FOR HIGH TEMPERATURES
IN THE LOWER 90S TO REACH ALL THE WAY TO LAKE MICHIGAN. HEAT
INDEX VALUES IN THE 100 TO 105 DEGREE RANGE ARE EXPECTED, WITH A
FEW SPOTS RISING ABOVE 105 DEGREES. VERY LITTLE RELIEF EXPECTED
OVERNIGHT WEDNESDAY WITH RIDGING KEEPING MCS ACTIVITY TO THE
NORTH AND LOW TEMPERATURES IN THE MID 70S. THURSDAY, SOUTHWEST
WINDS REMAIN IN PLACE, WITH HIGHS IN THE 90S AND HEAT INDICES
NEAR 100 DEGREES ONCE AGAIN. RIDGING BEGINS TO BREAK DOWN
THURSDAY AFTERNOON AS A SURFACE LOW PUSHES EASTWARD FROM THE
CENTRAL PLAINS INTO NORTHERN WISCONSIN, BRINGING POTENTIAL FOR
WIDESPREAD THUNDERSTORMS (30 TO 50 PERCENT CHANCE) ALONG A COLD
FRONTAL FEATURE THURSDAY AFTERNOON INTO FRIDAY.
FRONT LOOKS TO STALL OUT AS SURFACE LOW BEGINS TO FILL INTO
FRIDAY, BRINGING CONTINUED CHANCES (15 TO 30 PERCENT CHANCE) FOR
RAINFALL INTO SATURDAY. WITH THE STALLED FRONT AND WEAKENING
FLOW TO THE NORTH OF THE FRONT, EXPECTING CONTINUED VERY WARM
AND HUMID CONDITIONS FRIDAY INTO SATURDAY (HIGHS IN THE 80S AND
HEAT INDICES IN THE 90S). UNCERTAINTY IN THE FORECAST INCREASES
INTO THE WEEKEND AS THE STRENGTH OF THE SOUTHEAST U.S. RIDGING
AND THEREFORE THE PLACEMENT OF MCSS WOBBLES SLIGHTLY NORTH AND
SOUTH FROM RUN TO RUN. MORE RAINFALL WOULD LEAD TO LOWER
TEMPERATURES, BUT STRONGER RIDGING WOULD LEAD TO LESS RAINFALL
AND HIGHER TEMPERATURES.
MH
AVIATION
ISSUED 1035 PM CDT SUN JUL 20 2025
VISIBILITY MAY DIMINISH SLIGHTLY TONIGHT INTO MONDAY MORNING AS
WILDFIRE SMOKE MIXES TOWARD THE SURFACE, THOUGH OUR BEST GUESS
IS FOR 6 SM OR GREATER (VFR) VISIBILITY TO PREVAIL. SMOKE WILL
MIX OUT AS WINDS SHIFT TO SOUTHEASTERLY MONDAY MORNING INTO
MONDAY AFTERNOON.
DRY WEATHER AND MOSTLY CLEAR SKIES EXPECTED THROUGH MONDAY,
ALLOWING VFR TO CONTINUE. A FEW PERIODS OF SCATTERED HIGH-
ALTITUDE CLOUDS (SIMILAR TO THIS PAST AFTERNOON), AND PERHAPS A
FEW DIURNAL CUMULUS JUST OVER 4,000 FT TOWARDS SOUTHWESTERN WI
(LOOKING LESS FAVORABLE FOR SAID CLOUDS FURTHER NORTH AND EAST
DUE TO DRY AIR).
SHEPPARD
MARINE
ISSUED 312 PM CDT SUN JUL 20 2025
EXPECT NORTHERLY WINDS TO CONTINUE TO DIMINISH AS HIGH PRESSURE
EXITS TOWARD THE HUDSON BAY TONIGHT, THEN WINDS SHIFT EASTERLY
INTO MONDAY.
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 AND INTO THE SOUTHERN WISCONSIN NEARSHORE WATERS. A LOW
PRESSURE TROUGH WILL DROP THROUGH THE AREA THURSDAY NIGHT INTO
FRIDAY, SHIFTING WINDS TO WESTERLY.
MH
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
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