546
FXUS63 KMKX 190220 AAA
AFDMKX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
920 PM CDT MON AUG 18 2025
KEY MESSAGES
- SCATTERED SHOWERS AND STORMS WITH MODERATE TO HEAVY RAINFALL
SOUTH OF I-94 WILL GRADUALLY END FROM WEST TO EAST OVERNIGHT.
COULD SEE SOME LOCALIZED FLOODING WITH ANY HEAVIER SHOWERS
PERSISTING OVER THE SAME AREA. RISES ON AREA RIVERS WILL ALSO
BE POSSIBLE WITH THE EVENING ACTIVITY.
- DRIER AND LESS HUMID BY MIDWEEK.
UPDATE
ISSUED 920 PM CDT MON AUG 18 2025
THE ONGOING MCV THAT IS CROSSING SOUTHERN WI AND NORTHERN IL
WILL CONTINUE TO DRIFT EASTWARD THROUGH THE NIGHT. THERE IS A
BACK EDGE TO THE PRECIP AND IT IS SHOULD EXIT SOUTHEAST WI
BY 8 AM IF THE CURRENT TIMING HOLDS, BUT WILL LIKELY EXIT OR
DIMINISH EARLIER.
WE ISSUED TWO FLASH FLOOD WARNINGS OVER THE SOUTHERN THIRD OF
ROCK AND BELOIT COUNTIES DURING THE EVENING, WHERE THE RAIN
RATES WERE ON THE ORDER OF 2 INCHES PER HOUR. WE ARE NO LONGER
SEEING THOSE RAIN RATES OUT OF THIS SYSTEM (ISOLATED STORMS WITH
HALF TO 1 INCH RATES NOW), SO THE FLASH FLOOD CONCERNS ARE
DIMINISHING.
LOW CLOUDS AND SOME LIGHT FOG WILL DOMINATE CENTRAL AND MOST OF
SOUTHERN WI OVERNIGHT INTO TUESDAY MORNING. PATCHY DENSE FOG IS
POSSIBLE, BUT NOT EXPECTING WIDESPREAD.
CRONCE
SHORT TERM
ISSUED 334 PM CDT MON AUG 18 2025
TONIGHT THROUGH TUESDAY NIGHT:
INITIAL LINE OF STORMS ALONG THE REMNANT OUTFLOW BOUNDARY FROM
THIS MORNING CONTINUE TO PUSH OUT OVER THE LAKE. THIS HAS
WORKED OVER THE ENVIRONMENT ACROSS SOUTHERN WI FOR THIS
AFTERNOON, ESPECIALLY FOR AREAS NORTH OF I-94. HOWEVER,
INSTABILITY GRADIENT IS SHOWING SIGNS OF STEADILY RECOVERING
WITH 1000-2000 J/KG OF SBCAPE STREWN ACROSS AREAS SOUTH OF I-94,
LIKELY DUE TO THE INCREASE LOW-LEVEL MOISTURE AND A BIT OF SUN
PEAKING THROUGH. THUS STARTING TO SEE SOME ADDITIONAL
REDEVELOPMENT OF SHOWERS ALONG THIS GRADIENT AS THE MID- LEVEL
SHORTWAVE TROUGH AND REMNANT SURFACE MCV TRACK ACROSS SOUTHEAST
MN AND NORTHEAST IA AND INTO SOUTHWESTERN WI.
OVERALL THE POTENTIAL FOR STRONG STORMS AND HEAVIER RAIN LOOKS
FURTHER SOUTH INTO IL, BUT THERE SEEMS TO BE ENOUGH FORCING WITH
THIS MCV FEATURE AND MOISTURE TO BRING ADDITIONAL ROUNDS OF
SHOWERS AND STORMS INTO THE EVENING ALONG AND JUST NORTH OF THE
WI/IL BORDER. OVERALL THE STRONGER/SEVERE THREAT IS LIMITED, BUT
CANNOT RULE OUT AN ISOLATED STRONGER STORM OR TWO THOUGH INTO
THE EVENING WITH THE MAIN CONCERN BEING LOCALIZED DAMAGING WIND
GUSTS. THE MAIN CONCERN WILL BE THE POTENTIAL FOR HEAVY TO
MODERATE RAINFALL ALONG THE WEST TO EAST ORIENTATED
AFOREMENTIONED INSTABILITY GRADIENT WHERE THIS ACTIVITY IS
SUGGESTED TO DEVELOP INTO THE EVENING. THUS THIS WILL LEND WAY
MORE TO A FLOODING CONCERN WITH ANY REPEATED ROUNDS OF STORMS
OVER THE SATURATED AREAS. SO WILL NEED TO MONITOR WHERE THIS
ACTIVITY SETS UP AS 1-2" PER HOUR RATE ARE NOT OUT OF THE
QUESTIONS. LOCALIZED URBAN FLOODING AND RISE ON AREA RIVERS WILL
BE POSSIBLE THROUGH THE EARLY EVENING.
THEN EXPECTING THE SHORTWAVE TROUGH AND MCV TO PUSH EASTWARD
LATER THIS EVENING BRINGING A DRIER AIRMASS TO SOUTHERN WI
OVERNIGHT. HOWEVER, LOW-LEVEL MOISTURE AND LIGHT WINDS MAY LEAD
TO SOME PATCHY FOG DEVELOPMENT OVERNIGHT. FOR TUESDAY WILL SEE
NORTHERLY WINDS AS HIGH PRESSURE GRADUALLY BUILDS INTO THE UPPER
MIDWEST. WHILE CANNOT RULE OUT A FEW STRAY SHOWERS ON THE
BACKSIDE OF THE DEPARTING SYSTEM, THINKING IT WILL BE DRY ENOUGH
AIRMASS TO KEEP ANY ACTIVITY PRETTY ISOLATED.
WAGNER
LONG TERM
ISSUED 334 PM CDT MON AUG 18 2025
WEDNESDAY THROUGH MONDAY:
LONG STORY SHORT, THE ENTIRE LONG TERM FORECAST IS LOOKING
MOSTLY QUIET AND PLEASANT. THE RIDGE AXIS HOLDS TO OUR WEST
(OVER THE DAKOTAS / MINNESOTA) MID WEEK, LEAVING NORTHWEST FLOW
IN THE JET OVERHEAD, FAVORING SUBSIDENCE AND HIGH PRESSURE OVER
THE UPPER GREAT LAKES REGION WEDNESDAY AND THURSDAY. A NORTH TO
NORTHEAST BREEZE (AT THE SURFACE) THROUGHOUT THE REGION FORMS
WEDNESDAY, AND BECOMES A TAD GUSTY ALONG THE LAKE MICHIGAN
SHORELINE. AS SUCH, ELEVATED WAVES AND HIGH SWIM RISK CONDITIONS
MAY DEVELOP WEDNESDAY, ESPECIALLY FURTHER SOUTH TOWARDS THE
ILLINOIS BORDER. THE BREEZE ALSO HOLDS DAYTIME HIGH TEMPS TO THE
MID 70S TO AROUND 80 DEGREES. WINDS DECELERATE AND VEER FURTHER
EAST INTO THURSDAY, ALLOWING TEMPS TO MODERATE BACK UP TO THE
UPPER 70S / LOW 80S. SHALLOW MOISTURE MAY FORM SOME SCATTERED TO
BROKEN STRATOCUMULUS CLOUDS AT LOW ALTITUDES WEDNESDAY /
THURSDAY, AND A SPRINKLE (TRACE) OF RAIN FROM THESE CANNOT BE
COMPLETELY RULED OUT, BUT THE ATMOSPHERE IS COMPLETELY STABLE
ABOVE THIS LAYER. HENCE, NO CHANCE FOR THUNDERSTORMS OR
MEASURABLE RAINFALL BASED ON THE LATEST GUIDANCE.
MOVING ON TO FRIDAY, BOTH THE POLAR AND SUBTROPICAL JET STREAKS
AT 300-250MB BEGIN TO TROUGH SOUTHWARD INTO THE MIDWEST,
BRINGING THE JET STREAM OVERHEAD FOR MUCH OF THE EXTENDED,
PERHAPS EVEN WELL SOUTH OF THE REGION INTO EARLY NEXT WEEK. WITH
THE TROUGH AXIS SETTING UP ALONG OR EAST OF US, THE FLOW ALOFT
REMAINING OUT OF THE NORTHWEST, AND THE JET STREAM REMAINING
MOSTLY LAMINAR, PRECIP CHANCES ARE RELATIVELY LOW EACH DAY. A
COLD FRONT CROSSES THE REGION ON FRIDAY, AND COULD POTENTIALLY
SUPPORT A BRIEF ROUND OF CONVECTION ALONG IT, BUT WITH THE
PROGRESSIVE NATURE OF THE FRONT COUPLED WITH STIFF
NORTHWESTERLIES ALOFT MOVING IN BEHIND IT, ANY STORMS WOULD MOVE
OUT QUICKLY (NO POTENTIAL FOR TRAINING CONVECTION OR HEAVY
RAIN). WE ONLY AFFORD IT VERY LOW (GENERALLY LESS THAN 15%)
CHANCES OF PRODUCING ANY MEASURABLE PRECIP AT ALL, GIVEN THE
COMPLETE LACK OF MOISTURE RETURN (NO GULF MOISTURE) IN ADVANCE
OF THE FRONT. OUR BEST GUESS IS THAT IT PASSES THROUGH AS A DRY
COLD FRONT.
QUIET WEATHER CONTINUES INTO THE WEEKEND. TEMPERATURES HOLD
AROUND 80 / LOW 80S INTO FRIDAY BEFORE THE COLD FRONT, THEN
GRADUALLY FALL UNDER THE INFLUENCE OF GENTLE NORTHWESTERLY COLD
AIR ADVECTION. BY SUNDAY, DAYTIME HIGH TEMPS COULD FALL TO 70
DEGREES FLAT.
SHEPPARD
AVIATION
ISSUED 920 PM CDT MON AUG 18 2025
IFR CEILINGS HAVE MADE IT INTO CENTRAL WI ON LIGHT NORTHEAST
WINDS, AND ARE EXPECTED TO SPREAD INTO ALL OF SOUTHERN WI DURING
THE EARLY OVERNIGHT HOURS AS WEAK LOW PRESSURE FINALLY EXITS WI.
THE ONGOING SHOWERS AND THUNDERSTORMS ACROSS FAR SOUTHERN WI
WILL SLOWLY EXIT FROM WEST TO EAST OVERNIGHT, POSSIBLY NOT
ENDING UNTIL CLOSER TO 12Z IN FAR SOUTHEAST WI. PATCHY FOG IS
POSSIBLE TONIGHT, ALTHOUGH THERE IS HIGHER PROBABILITY OF WIDESPREAD
LIFR CEILINGS BELOW 500 FT. THE IFR CEILINGS SHOULD IMPROVE TO
MVFR BY MIDDAY, THEN VFR BY MID AFTERNOON, AND OVERALL CLOUD
COVER MAY NOT START TO SCATTER OUT UNTIL LATER IN THE
AFTERNOON. AREAS TOWARD WESTERN WI HAVE THE BEST CHANCE OF
CLEARING EARLIER.
CRONCE
MARINE
ISSUED 920 PM CDT MON AUG 18 2025
WEAK LOW PRESSURE CROSSING SOUTHERN WISCONSIN THIS EVENING WILL
CROSS SOUTHERN LOWER MICHIGAN ON TUESDAY. HIGH PRESSURE SITTING
OVER ONTARIO WILL REMAIN IN PLACE THROUGH MUCH OF THE WEEK. A
PERIOD OF ELEVATED NORTHERLY WINDS IS EXPECTED TUESDAY, THEN
LIGHT AND VARIABLE WINDS WILL DEVELOP AS THE HIGH GLIDES OVER
LAKE MICHIGAN LATER IN THE WEEK.
CRONCE
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
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