987
FXUS63 KMKX 211434
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
934 AM CDT MON APR 21 2025
KEY MESSAGES
- THUNDERSTORM CHANCES RETURN TUESDAY MORNING/AFTERNOON WITH A
POTENTIAL FOR AN ISOLATED STRONG TO SEVERE THUNDERSTORM OR TWO
CAPABLE OF PRODUCING HAIL. MAY BE AN ADDITIONAL WINDOW FOR
THUNDERSTORMS TUESDAY EVENING IN SOUTHWEST WI, BUT MORE
UNCERTAINTY WITH THIS ROUND.
- POSSIBLE FLASH FLOODING THREAT LATE TUESDAY NIGHT INTO
WEDNESDAY MORNING IF STORMS DEVELOP/ALIGN ALONG A WEST TO EAST
BOUNDARY NEAR THE WI/IL BORDER.
- TEMPS WILL WARM UP THROUGH THE END OF THE WEEK WITH WELL
ABOVE NORMAL HIGHS AND THERE WILL BE ADDITIONAL RAIN AND
THUNDERSTORM CHANCES FOR THE SECOND HALF OF THE WEEK.
UPDATE
ISSUED 934 AM CDT MON APR 21 2025
EXTENSIVE CLOUD COVER SHOULD LINGER ACROSS MUCH OF WISCONSIN
TODAY WITH SOME CLEARING FROM WEST TO EAST BY SUNSET AS A LOW
PRESSURE SYSTEM NEAR GREEN BAY LIFTS NORTHWARD TODAY. SOME
DRIZZLE IN EASTERN WI WILL QUICKLY CLEAR THIS MORNING AS DRIER
AIR MOVES IN. THE MAIN THING FOR TODAY WILL BE THE WINDY
CONDITIONS IN THE CAA REGION OF THE LOW AIDING MIXING UP TO
850MB ACROSS SOUTHERN WI. EXPECT WINDS TO WEAKEN FROM SOUTH TO
NORTH TODAY AS THE TIGHTER PRESSURE GRADIENT FOLLOWS THE LOW AND
A SURFACE RIDGE AXIS MOVES IN.
THE FOCUS WILL THEN GO ONTO CONVECTIVE TRENDS TUESDAY AND
WEDNESDAY. THE FIRST SHOT AT STORMS APPEARS TO BE ON TUESDAY
MORNING TOWARD DAYBREAK AS A SURFACE LOW MOVES THROUGH MN AND
PULLS A NW TO SE ORIENTED WARM FRONT ACROSS SW WI. SOME
CONVECTION IS EXPECTED TO DEVELOP SOMEWHERE ALONG THE FRONT IN
WESTERN WI OVERNIGHT/EARLY TUESDAY. FORCING IS ALL IN THE LOW
LEVELS DUE TO THE FRONT WITH POOR LAPSE RATES ALOFT. SO, CAN'T
RULE OUT SOME HAIL BUT NOT EXPECTING A WIDESPREAD ISSUE.
INITIAL LOOK AT THE REST OF TUESDAY AND WEDNESDAY SHOWS SOME
BETTER INSTABILITY DEVELOPING TUESDAY AFTERNOON IN SW WI BUT
IT'S A QUESTION OF IF THERE'S A TRIGGER THERE WITH THE
FRONT/BOUNDARY APPEARING TO BE IN NORTHERN IL. WHERE THAT
BOUNDARY SETS UP COULD ALSO LEAD TO A FLASH FLOOD THREAT IF IT
SITS WEST TO EAST ALONG THE IL BORDER.
HALBACH
SHORT TERM
ISSUED 339 AM CDT MON APR 21 2025
TODAY THROUGH TUESDAY NIGHT:
THE SURFACE LOW AND ACCOMPANYING MID-LEVEL SHORTWAVE TROUGH
CONTINUE TO LIFT ACROSS CENTRAL WI AND INTO NORTHERN PORTIONS
OF LAKE MICHIGAN THROUGH THE MORNING. THE BULK OF THE SHOWER
ACTIVITY HAS ALREADY PUSHED THROUGH OVERNIGHT AND A DRY SLOT IS
LIMITING ADDITIONAL WIDESPREAD COVERAGE FROM DEVELOPING.
HOWEVER, SPORADIC/SCATTERED LIGHT SHOWER CHANCES WILL LINGER
THROUGH DAYBREAK BEFORE DIMINISHING BY MID MORNING HOURS AS A
COLD FRONT PUSHES THROUGH THE AREA. LOOKING AT DRIER CONDITIONS
BEHIND THE COLD FRONT FOR THE REST OF DAY, BUT GIVEN THE LOW
DEEPENING TO SUB 1000MB, THE PRESSURE GRADIENT WILL REMAIN
TIGHT ACROSS SOUTHERN WI. THUS RESULTING IN STRONGER WESTERLY
GUSTS OF 20-30 MPH THROUGH THE AFTERNOON WITH THE STRONGEST
GUSTS POSSIBLY EVEN APPROACHING 35-40 MPH FOR EAST-CENTRAL
PORTIONS OF WI.
OTHERWISE, WINDS WILL DIMINISH THROUGH THE EVENING AS HIGH
PRESSURE AND UPPER-LEVEL RIDGE QUICKLY TRAVERSES JUST SOUTH OF
THE AREA. SHOULD SEE LIGHT WINDS AND COOL CONDITIONS OVERNIGHT
WITH LOWS DIPPING INTO THE MID TO UPPER 30S.
THEN A MID-LEVEL SHORTWAVE TROUGH FROM THE NORTHERN PLAINS IS
PROGGED TO FOLLOW RIGHT BEHIND THE RIDGE AND PUSH INTO THE
UPPER MIDWEST LATER TONIGHT/EARLY TUESDAY MORNING. THIS SYSTEM
WILL THE FOCUS FOR OUR NEXT ROUND OR TWO OF SHOWERS/STORMS. THE
ASSOCIATED SURFACE LOW PAIRED WITH THE UPPER-LEVEL WAVE IS
EXPECTED TO BREAK AWAY AND MEANDER UP THE ND/MN BORDER THROUGH
TUESDAY. AHEAD OF IT A WING OF LOW-LEVEL WAA WILL LIFT UP THE
UPPER MISSISSIPPI RIVER VALLEY TUESDAY MORNING. THE LOW-LEVEL
DYNAMICS PAIRED WITH A SWATH OF MUCAPE 500-750 J/KG, STEEP MID-
LEVEL LAPSE RATES (7.5-8.0C/KM), NOSE OF 850MB LLJ, AND
INCREASED DEEP LAYER SHEAR LOOKS TO SUPPORT ELEVATED CONVECTION.
WITH THE MORNING ROUND OF ELEVATED STORMS, COULD SEE A FEW
STRONGER AND EVEN AN ISOLATED SEVERE STORM OR TWO CAPABLE OF
PRODUCING LARGE HAIL DEVELOP ACROSS SOUTHERN WI DAYBREAK THROUGH
THE EARLY AFTERNOON.
THERE MAY BE ADDITIONAL ROUND OF SHOWERS AND CONVECTION TO
DEVELOP LATER IN THE AFTERNOON AND EARLY EVENING IF THE SURFACE
WARM FRONT AND NOSE OF THE HIGHER SURFACE MOISTURE LIFTS NORTH
OF THE WI/IL BORDER. THERE IS A BIT MORE UNCERTAINTY WITH THIS
ROUND AS THE ENVIRONMENT MAY NOT HAVE ENOUGH TIME TO RECOVER
AFTER THE MORNING ROUND OF STORMS ALONG WITH EASTERLY FLOW OFF
OF THE LAKE PREVENTING IT FROM LIFTING. HOWEVER THERE ARE HINTS
THAT IT MAY HAVE ENOUGH MOMENTUM TO LIFT NORTH INTO OUR CWA
ESPECIALLY FOR SOUTH-CENTRAL AND SOUTHWESTERN PORTIONS. IF THE
WARM FRONT IS ABLE TO MAKE IT NORTH OF THE CHEDDAR CURTAIN, THEN
COULD SEE MORE SURFACE BASED CONVECTION DEVELOP, WHICH MAY BE
CAPABLE OF PRODUCING HAIL AND GUSTY WINDS. AGAIN, UNCERTAINTY
REMAINS GREATER AS IT LOOKS TO BE NARROW WINDOW THAT FAVORS
CONVECTION DEVELOPMENT INTO THE EVENING HOURS.
WAGNER
LONG TERM
ISSUED 339 AM CDT MON APR 21 2025
WEDNESDAY THROUGH SUNDAY:
WEDNESDAY MORNING IS EXPECTED TO REMAIN DRY AT THIS TIME AS
ANOTHER SURFACE WARM FRONT SHARPENS JUST SOUTH OF THE BORDER
THROUGH THE DAYTIME HOURS. BY WEDNESDAY EVENING, THUNDERSTORM
ACTIVITY IS EXPECTED TO BLOSSOM AND EVENTUALLY MOVE INTO
SOUTHWESTERN WI WEDNESDAY NIGHT INTO THURSDAY FOLLOWING WARM
ADVECTION OF THE LLJ NORTHWARD. BY THURSDAY MORNING, MOST OF THE
SHOWER ACTIVITY WITH THE FRONT SHOULD BE NORTH OF OUR CWA, AND
WE STAND TO REMAIN DRY MOST OF THE DAY GIVEN MOST OF THE BETTER
FORCING FOR ASCENT WILL BE EITHER NORTH OR WEST OF US. THURSDAY
NIGHT, HOWEVER, A SLOW MOVING FRONTAL BOUNDARY IS EXPECTED TO
MOVE TOWARD WESTERN WI BRINGING CHANCES FOR OVERNIGHT SHOWERS
AND STORMS INTO FRIDAY MORNING. MODELS DEPICT THE BOUNDARY
LINGERING ENOUGH ON FRIDAY TO ALLOW SOME DESTABILIZATION AND
SOME MORE SHOWER AND STORM FORMATION FRIDAY AFTERNOON OVER
SOUTHEAST WISCONSIN BEFORE THE FRONT CLEARS THE STATE.
BEYOND, HIGH PRESSURE LOOKS TO TAKE HOLD FOLLOWING THE FRONTAL
PASSAGE WITH SEASONABLE TEMPERATURES IN THE UPPER 50S TO LOW 60S
REMAINING OVER THE REGION.
CMILLER
AVIATION
ISSUED 934 AM CDT MON APR 21 2025
MVFR CEILINGS ARE WIDESPREAD ACROSS SOUTHERN WISCONSIN AND WILL
GRADUALLY IMPROVE THROUGH THE AFTERNOON FROM SOUTH TO NORTH.
CONDITIONS WILL BE WINDY TODAY AS WELL BUT ALSO START WEAKENING
FROM SOUTH TO NORTH THROUGH THE AFTERNOON INTO TONIGHT AS A
RIDGE OF HIGH PRESSURE MOVES IN. QUESTIONS FOR TUESDAY WITH IF
AND WHEN SOME ISOLATED/SCATTERED THUNDERSTORMS COULD OCCUR, MORE
SO IN SOUTHWEST WISCONSIN. OTHERWISE VFR CONDITIONS EXPECTED
AFTER THE CIGS IMPROVE TODAY.
HALBACH
MARINE
ISSUED 339 AM CDT MON APR 21 2025
LOW PRESSURE WILL CONTINUE NORTH-NORTHEAST AND TRACK ACROSS
NORTHERN LAKE MICHIGAN THROUGH TODAY AND MOVING TO NORTH OF
LAKE HURON TONIGHT. BREEZY SOUTHEASTERLY WINDS WILL QUICKLY
BECOME SOUTHERLY, THEN SOUTHWESTERLY AFTER DAYBREAK, WITH
PATCHY GALE FORCE GUSTS OVER MOST OF THE OPEN WATERS THROUGH
TODAY. A GALE WARNING REMAINS IN EFFECT FROM 7AM TO 7PM CDT FOR
AREAS SOUTH OF THE CENTER OF THE LOW PRESSURE.
WINDS THEN BECOME WESTERLY LATE THIS AFTERNOON AND EVENING AND
WILL GRADUALLY EASE OVERNIGHT INTO TUESDAY MORNING. LIGHT
NORTHWESTERLY WILL BEGIN TO TURN THROUGH TUESDAY AFTERNOON AS
THE SURFACE HIGH PRESSURE PASSES PUSHES EAST OF THE LAKE. WINDS
THEN INCREASE AND BECOME SOUTHEASTERLY TUESDAY
AFTERNOON/EVENING AHEAD OF A WARM FRONT LIFTS AND STALLS ACROSS
THE SOUTHERN THIRD OF LAKE MICHIGAN TUESDAY EVENING. LIGHTER
WINDS ARE EXPECTED FOR THE MIDDLE OF THE WEEK AS HIGH PRESSURE
BUILDS IN FROM THE WEST.
CMILLER/WAGNER
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ643-LMZ644-LMZ645-LMZ646-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
LMZ876-LMZ878 UNTIL 7 PM MONDAY.
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