444
FXUS63 KMKX 260957
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
457 AM CDT SAT SEP 26 2026
KEY MESSAGES
- PATCHY FOG CONTINUES THROUGH DAWN BEFORE DISSIPATING. SOME
POCKETS MAY BECOME DENSE.
- TEMPERATURES WITHIN A COUPLE DEGREES OF NORMAL OVER THE NEXT
SEVERAL DAYS.
- CHANCES FOR RAIN AND A FEW STORMS RETURN TUESDAY INTO TUESDAY
NIGHT.
UPDATE
ISSUED 455 AM CDT SAT SEP 26 2026
PATCHY FOG HAS FORMED OVER PARTS OF SOUTHERN WISCONSIN THIS
MORNING. SOME POCKETS HAVE BECOME LOCALLY DENSE. THIS FOG SHOULD
CONTINUE THROUGH DAWN BEFORE DAYTIME MIXING CAUSES IT TO
DISSIPATE.
OTHERWISE EXPECT A MIX OF SUNSHINE AND HIGH CLOUDS TODAY AS SOME
WAA MOVES OVERHEAD. TEMPS WILL BE PLEASANT IN THE MID TO UPPER
60S WITH LIGHT WINDS.
CMILLER
SHORT TERM
ISSUED 1000 PM CDT FRI SEP 25 2026
SATURDAY THROUGH MONDAY:
WITH SOME GAPS FORMING IN THE CLOUD COVER, AND RADIATIONAL
COOLING ALREADY SENDING A FEW METAR SITES TO SATURATION, SOME
PATCHY GROUND FOG IS POSSIBLE OVERNIGHT INTO EARLY SATURDAY
MORNING. NOTHING PARTICULARLY WIDESPREAD IS EXPECTED GIVEN THE
OCCASIONAL UPPER-ALTITUDE CLOUD COVER AND VERY DRY BOUNDARY
LAYER, MAINLY JUST THE MOST SUSCEPTIBLE LOW-LYING MARSHY AREAS
AND RIVER VALLEYS EXPECTED TO SEE THIS FOG.
HIGH PRESSURE REMAINS DOMINANT OVER SOUTHERN ONTARIO CANADA AND
THE GREAT LAKES THROUGH THE REST OF THE WEEKEND AND INTO EARLY
NEXT WEEK, SLOWLY WEAKENING WITH TIME. NEAR NORMAL TEMPERATURES
AND PREDOMINANTLY DRY WEATHER IS EXPECTED THROUGH THE PERIOD,
WITH HIGHS IN THE MID TO UPPER 60S THIS WEEKEND AND ROUGHLY 70
DEGREES ON MONDAY. LOWS WILL BE AROUND 50 DEGREES, LOCALLY
COOLER IN SOME AREAS (MID 40S). A LIGHT NORTHEAST OR SOUTHEAST
BREEZE ACROSS THE REGION AT TIMES (GENERALLY 10 MPH OR LESS),
OTHERWISE PRACTICALLY CALM.
OUR BEST SHOT AT A STRAY RAIN SHOWER THIS WEEKEND WOULD BE
SATURDAY NIGHT INTO SUNDAY MORNING (10-15% CHANCE), MAINLY WEST
OF A JANESVILLE TO GREEN LAKE LINE AS AN ADDITIONAL ROUND OF
MID-LEVEL WAA AND CYCLONIC FLOW ALOFT ATTEMPTS TO PUSH EAST
INTO SOUTHERN WI. LOW-LEVEL DRY AIR SHOULD EVAPORATE MOST OF
IT.
SHEPPARD
LONG TERM
ISSUED 1000 PM CDT FRI SEP 25 2026
MONDAY NIGHT THROUGH FRIDAY:
THE AFOREMENTIONED HIGH PRESSURE SHIFTS INTO THE OHIO VALLEY
INTO TUESDAY. MEANWHILE, A POSITIVELY-TILTED UPPER TROUGH DIGS
EAST FROM NEVADA INTO UTAH, ALLOWING DIFFLUENT UPPER-LEVEL FLOW
TO OVERSPREAD THE GREAT PLAINS AND FORM BROAD LOW PRESSURE AT
THE SURFACE. SOUTHERLY WAA WILL DEVELOP BETWEEN THE TWO PRESSURE
SYSTEMS TUESDAY, DRIVING RAIN CHANCES THAT BUILD WEST TO EAST
INTO SOUTHERN WI THROUGH THE DAY. WIDESPREAD 50-65% RAIN CHANCES
ARE THEN FORECAST INTO TUESDAY NIGHT (DUE TO POTENTIAL FOR A
LLJ TO FORM OVERHEAD AND REINFORCE THE RAIN SHOWERS). INSTABILITY
IS LOOKING VERY LIMITED FOR NOW, BUT A FEW RUMBLES OF THUNDER
CAN'T BE RULED OUT TUESDAY NIGHT. SOME OF THIS RAIN COULD THEN
LINGER INTO WEDNESDAY MORNING.
FROM MIDDAY WEDNESDAY ONWARDS, PREDICTABILITY REMAINS VERY LOW
AT THIS TIME; ENSEMBLES MEMBERS CONTINUE TO DISAGREE ON WHETHER
THE AFOREMENTIONED UPPER TROUGH WILL REMAIN AN OPEN WAVE (AND
TRACK FASTER) OR CLOSE OFF INTO A PSEUDO "UPPER LOW" (AND TRACK
SLOWER). EVEN AMONGST ENSEMBLE MEMBERS THAT AGREE ON THE PHASE
OF THE TROUGH, THERE IS CONSIDERABLE VARIABILITY ON THE TRACK OF
ANY ATTENDANT SURFACE LOW PRESSURE. 500MB CLUSTER ANALYSIS
REVEAL EVEN GREATER ENSEMBLE DISPERSION REGARDING THE LONGWAVE
TROUGH/RIDGE PATTERN OF THE POLAR JET ALONG THE US / CANADA
BORDER. IN OTHER WORDS, THE CENTRAL CONUS AS A WHOLE IS IN FOR
ACTIVE WEATHER (RAIN AND THUNDER) MID TO LATE NEXT WEEK, BUT
WHETHER OR NOT THAT SPECIFICALLY INCLUDES SOUTHERN WI (OR SETS
UP FURTHER SOUTH) IS TO BE DETERMINED. ON THE BRIGHT SIDE, THUNDER
POTENTIAL CAN GENERALLY BE LIMITED TO "SLIGHT CHANCE" IN THE
FORECAST FOR NOW, GIVEN THAT GEFS INSTABILITY PLUMES ARE
PREDOMINANTLY CENTERED WELL SOUTH OF OUR REGION.
SHEPPARD
AVIATION
ISSUED 456 AM CDT SAT SEP 26 2026
PATCHY DENSE FOG CONTINUES UNTIL AFTER DAWN WITH VIS DOWN TO
1/4SM IN ISOLATED SPOTS. AFTER THE FOG DISSIPATES, EXPECT VFR
CONDITIONS THROUGH TODAY AND LIGHT EAST TO SOUTHEASTERLY WINDS.
CMILLER
MARINE
ISSUED 1000 PM CDT FRI SEP 25 2026
OPEN WATERS / SYNOPSIS:
HIGH PRESSURE AROUND 30.3 INCHES WILL LINGER OVER SOUTHERN
ONTARIO CANADA AND THE GREAT LAKES THROUGH THE WEEKEND AND INTO
MONDAY, GRADUALLY WEAKENING TO 30.1 INCHES. QUIET WEATHER
EXPECTED THROUGH SAID PERIOD, WITH LIGHT NORTHEAST TO SOUTHEAST
WINDS (LIGHT AND VARIABLE AT TIMES).
HIGH PRESSURE WILL PROGRESS INTO THE OHIO VALLEY EARLY TUESDAY,
ALLOWING WINDS TO TURN SOUTH AND INCREASE AS LOW PRESSURE
APPROACHES FROM THE WEST.
NEARSHORE ZONES:
BREEZY SOUTH WINDS AND BUILDING WAVES ARE FORECAST TUESDAY NIGHT
THROUGH WEDNESDAY. CONDITIONS COULD POTENTIALLY BECOME HAZARDOUS
TO SMALL CRAFT.
SHEPPARD
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
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