017
FXUS63 KMKX 230821
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
321 AM CDT WED APR 23 2025
KEY MESSAGES
- SCATTERED SHOWER AND THUNDERSTORM CHANCES THIS MORNING FOR
SOUTHWEST AND SOUTH CENTRAL WI. OFF AND ON SCATTERED STORM
CHANCES PERSIST THROUGH THIS AFTERNOON/EVENING WITH A
POTENTIAL FOR A FEW ISOLATE STRONG TO SEVERE STORMS.
- WELL ABOVE NORMAL TEMPS FOR TODAY AND THURSDAY WITH HIGHS IN
THE UPPER 60S AND LOW 70S, BUT COOLER TEMPS BY LAKE MICHIGAN.
- ANOTHER ROUND OF SHOWERS AND A FEW THUNDERSTORM ALONG WITH
COOLER TEMPS FOR FRIDAY.
- DRIER THIS WEEKEND BUT ANOTHER WINDOW WITH A POTENTIAL FOR
STRONG TO SEVERE STORMS EARLY NEXT WEEK.
SHORT TERM
ISSUED 313 AM CDT WED APR 23 2025
TODAY THROUGH THURSDAY:
MAIN FOCUS FOR TODAY WILL BE THE WAFFLING STALLED FRONTAL
BOUNDARY CURRENTLY SITTING JUST SOUTH ACROSS IA/IL. HAVE BEEN
SEEING CONVECTION DEVELOP ALONG THE BOUNDARY OVERNIGHT WITH AN
OCCASIONAL TALLER STORM PRODUCING SEVERE HAIL BACK IN IA.
OVERALL THERE REMAINS LIMITED IF ANY UPPER-LEVEL SUPPORT FOR
THIS ACTIVITY WITH THE CORE OF THE UPPER-LEVEL JET STRUNG
FURTHER NORTH ACROSS THE DAKOTAS AND MN BORDER AND MID-LEVEL
VORTICITY MAX WITH THE SHORTWAVE TROUGH ALONG THE MN/CANADIAN
BORDER. THE ONGOING SCATTERED STORMS ARE MAINLY BEING DRIVEN BY
CONVERGENCE ALONG THE SURFACE BOUNDARY AND ADDITIONAL
DEVELOPMENT IS LIKELY BEING TRIGGERED BY MESOSCALE FORCING SUCH
AS OUTFLOWS FROM NEARBY DECAYING CONVECTION. SO WILL MONITOR
THESE TRENDS THROUGH THE EARLY MORNING HOURS AS THE BETTER
FORCING REMAINS SOUTH OF THE WI/IL BORDER.
EXPECTING THIS STALLED BOUNDARY TO GRADUALLY LIFT NORTHWARD
THROUGH DAYBREAK AS A SHALLOW LOW-LEVEL (700MB) AND SURFACE
TROUGH IS PROGGED TO LIFT NORTHWARD UP THE MISSISSIPPI RIVER
VALLEY ALONG WITH A MODEST 30KT 850MB JETLET, WHERE THE LATEST
CONVECTIVE DEVELOPMENT IS OCCURRING. AS THE SURFACE BOUNDARY
PUSHES NORTH OF THE CHEDDAR CURTAIN INTO SOUTHERN WI, EXPECTING
THE SCATTERED SHOWER AND FEW THUNDERSTORM CHANCES TO FOLLOW
SUITE THROUGH THE MORNING. AGAIN THIS ACTIVITY LACKS UPPER-LEVEL
DYNAMICS/SUPPORT, BUT THERE WILL BE ENOUGH LOW-LEVEL
CONVERGENCE PAIRED WITH DEWPOINTS CLIMBING INTO THE 50S FOR OFF-
ON SHOWER/STORM CHANCES THROUGH MUCH OF THE DAY. THUS TODAY IS
NOT GOING TO BE A COMPLETE WASH OUT AS THERE WILL BE PERIODIC
DRY PERIODS.
THE 00Z CAMS/HREF MEMBERS AGREE WITH THIS TREND OF STORMS
CHANCES GRADUALLY LIFTING NORTHWARD THROUGH THE MORNING. AGAIN
THE MAIN DRIVER FOR CONVECTION WILL BE THE SURFACE BOUNDARY
ITSELF ALONG WITH ANY NEARBY MESOSCALE FORCING MECHANISMS SUCH
AS REMNANT OUTFLOWS OR EVEN POTENTIALLY THE LAKE BREEZE THIS
AFTERNOON. WHILE NOT EXPECTING WIDESPREAD DEVELOPMENT OF
STRONGER STORMS, CANNOT NOT RULE OUT SEEING A FEW ISOLATED
STORMS GROW MORE UPSCALE AND EVEN BECOME SEVERE AS IT TAPS INTO
THE MODEST DEEP LAYER (0-6KM) SHEAR AROUND 30KT ALONG WITH
SBCAPE PROGGED TO TOP OFF BETWEEN 500-1000J/KG BY THE
AFTERNOON/EVENING. MAINLY WOULD BE HAIL THREAT IF ANY
STRONGER/SEVERE STORMS DEVELOP, BUT COULD SEE SOME GUSTY WINDS
MIX DOWN GIVEN SOME HINTS OF STEEPER LOW-LEVEL LAPSE RATES
APPROACHING 7C/KM. ADDITIONALLY IF ANY STORMS TRAIN OVER THE
SAME AREA FOR EXTENDED PERIOD OF TIME, THEN WE CANNOT RULE OUT A
LOCALIZED FLASH FLOODING POTENTIAL, BUT GIVEN THE
BOUNDARY/CONVECTION LOOKS TO BE FAIRLY PROGRESSIVE AS IT MOVES
ACROSS SOUTHERN WI MAY LIMIT THE CONCERN.
AS WE LOSE DAYTIME HEATING AND AS THE FRONTAL BOUNDARY IS
PROGGED TO LIFT NORTHWARD THIS EVENING, EXPECTING A DECREASE IN
SHOWER/STORM CHANCES OVERNIGHT INTO THURSDAY. THURSDAY DOES LOOK
TO BE A BIT DRIER THROUGH THE MORNING AND EARLY HALF OF THE
AFTERNOON WITH THE FRONT NORTH OF THE AREA. HOWEVER ADDITIONAL
SCATTERED SHOWER AND THUNDERSTORMS CHANCES WILL RETURN LATER ON
THURSDAY AS THE FRONTAL BOUNDARY LOOKS TO SHIFT BACK SOUTHWARD
AS HIGH PRESSURE BUILDS ACROSS THE UPPER MIDWEST AND AS A RIPPLE
OF MID-LEVEL IS PROGGED TO TREK ACROSS THE REGION. AS THE
BOUNDARY BEGINS TO SHIFT SOUTH, THERE CONTINUES TO BE HINTS OF A
BACKDOOR COLD FRONT TO WORKS ITS WAY DOWN ACROSS LAKE MICHIGAN
TO HELP SHIFT THE BOUNDARY SOUTHWARD AND BRING COOLER TEMPS FOR
THE LAKESHORE AREAS LATER THURSDAY AFTERNOON/EVENING.
IN BETWEEN THE SHOWER/THUNDERSTORM CHANCES, SOUTHERN WI IS
LOOKING A A WARMER STRETCH TODAY AND THURSDAY WITH HIGHS IN THE
UPPER 60S AND LOW 70S FOR INLAND PORTIONS. MEANWHILE AREAS LOOK
TO BE A BIT COOLER BY THE LAKE WEDNESDAY AND ESPECIALLY ON
THURSDAY WITH THE POTENTIAL OF THE BACKDOOR COLD FRONT FEATURE.
WAGNER
LONG TERM
ISSUED 313 AM CDT WED APR 23 2025
THURSDAY NIGHT THROUGH TUESDAY:
THE ACTIVE PATTERN WILL CONTINUE OVERNIGHT THURSDAY AS ANOTHER
ROUND OF SHOWERS AND STORMS WILL BE POSSIBLE AHEAD OF AN
INCOMING SYSTEM TRACKING UP FROM THE PLAINS. AN ELONGATED SFC
TROUGH IS EXPECTED TO CLOSE OFF INTO A SURFACE LOW ALONG THE
WISCONSIN AND ILLINOIS BORDER FRIDAY MORNING. THE GFS AND NAM
STRUGGLE TO PRODUCE MUCAPE OVER THE REGION, GIVEN SATURATED
CONDITIONS ALOFT, SO MOST OF THE ACTIVITY FRIDAY MORNING SHOULD
BE THUNDERLESS. THE LOW WILL PROGRESS EAST THROUGH THE DAY, WITH
RAIN COMING TO AN END FRIDAY AFTERNOON/EVENING. HIGH PRESSURE
WILL BUILD INTO THE UPPER GREAT LAKES SATURDAY AND SUNDAY WITH A
SLIGHT COOLING IN TEMPS TO THE LOW 60S SATURDAY AND THEN MID TO
UPPER 60S SUNDAY AS WARM ADVECTION STARTS OVER THE REGION AS A
LARGE UPPER RIDGE SHIFTS EAST FROM THE PLAINS.
MONDAY AND TUESDAY WILL THEN SEE ENHANCED WARMTH AND HUMIDITY
BUILDING INTO THE UPPER MISSISSIPPI VALLEY AS THE HIGH AMPLITUDE
RIDGE MOVES OVERHEAD. WITH SOUTHWESTERLY FLOW ALOFT AND PASSING
WEAK SHORTWAVES, CHANCES FOR THUNDERSTORMS ARE EXPECTED TO
BEGIN MONDAY AND LINGER THROUGH TUESDAY UNTIL A SHARP TROUGH
DIGS AND SWINGS THROUGH THE UPPER MIDWEST TUESDAY NIGHT. GIVEN
THE OVERLAP OF CAPE AND SHEAR OVER OUR REGION DURING THIS TIME,
SEVERE WEATHER DOES APPEAR POSSIBLE, BUT IT IS TOO EARLY TO
ASSIGN A DISCERNIBLE AREA/THREAT MAGNITUDE TO ANY STORMS WE SEE
AT THE END OF THE EXTENDED PERIOD.
CMILLER
AVIATION
ISSUED 313 AM CDT WED APR 23 2025
BEGINNING TO SEE SOME FOG DEVELOPMENT ACROSS SOUTHWESTERN WI
EARLY THIS MORNING AS MOISTURE INCREASES AHEAD OF THE INCOMING
WARM FRONT. MAY SEE ADDITIONAL DEVELOPMENT FOR AREAS ALONG AND
WEST OF I-90 CORRIDOR THROUGH DAYBREAK. THEN EXPECTING TEMPS TO
INCREASE TO LIMIT ADDITIONAL FOG DEVELOPMENT AFTER DAYBREAK.
OTHERWISE, MAIN CONCERN WILL BE THE THE OFF AND ON SHOWER AND
THUNDERSTORM ACTIVITY EXPECTED ACROSS SOUTHERN WI THROUGH THE
DAY AS THE WARM FRONT LIFTS NORTHWARD. WINDS ARE LOOKING TO
REMAIN FAIRLY LIGHT DURING THE PERIOD BUT GRADUALLY TURN MORE
SOUTH-SOUTHWEST BEHIND THE WARM FRONT. WITH ANY
SHOWER/THUNDERSTORM EXPECT A BRIEF PERIOD FOR LOWER CEILINGS
AND VISIBILITY ALONG WITH A POTENTIAL FOR SOME HAIL AND GUSTY
WINDS. WILL SEE THIS POTENTIAL CONTINUE INTO THE EVENING BEFORE
THE FRONT LIFTS FURTHER NORTH. GIVEN THE LIGHT FLOW AND THE
INCREASED LOW-LEVEL MOISTURE CANNOT RULE OUT FOG DEVELOPMENT
OVERNIGHT INTO THURSDAY MORNING AS WELL.
WAGNER
MARINE
ISSUED 313 AM CDT WED APR 23 2025
LOW PRESSURE CONTINUES TO SLOWLY WEAKEN AS IT LIFTS NORTH OF MN
INTO SOUTH CENTRAL CANADA. LIGHT AND VARIABLE WINDS PERSIST
OVER LAKE MICHIGAN AS A WEAK WARM FRONT IS EXPECTED TO LIFT
NORTH THROUGH THE MORNING AND CONTINUE NORTHWARD THROUGH THIS
EVENING INTO THURSDAY. EXPECTING PERIODIC SHOWER AND
THUNDERSTORM CHANCES ALONG THE FRONTAL BOUNDARY AS IT SLIDES
NORTH. WHILE WINDS REMAIN FAIRLY LIGHT EXPECTING MORE EASTERLY
WINDS NORTH OF THE WARM FRONT WITH MORE SOUTHERLY WINDS SOUTH OF
THE BOUNDARY. EXPECTING TO SEE THE FRONT TO WAFFLE BACK SOUTH
AND GRADUALLY WASH OUT INTO THURSDAY AS HIGH PRESSURE BUILDS
ACROSS THE UPPER GREAT LAKES. WINDS LOOK TO BE VARIABLE THROUGH
THE END OF THE WEEK BEFORE GRADUALLY INCREASING INTO FRIDAY AS
ANOTHER SURFACE LOW WORKS IT WAY ACROSS THE MIDWEST FROM THE
PLAINS.
WAGNER
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
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