255
FXUS63 KMKX 180215
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
915 PM CDT SUN MAY 17 2026
KEY MESSAGES
- DECAYING SQUALL LINE WITH GUSTY WINDS TO MOVE INTO SOUTH
CENTRAL WI DURING THE EARLY MORNING HOURS. MARGINAL
PROBABILITIES FOR SEVERE WIND GUSTS OVER SAID REGION.
- ANOTHER ROUND OF SHOWERS AND STORMS LATE MONDAY NIGHT INTO
TUESDAY WITH A POTENTIAL FOR STRONG TO SEVERE STORMS.
- COOL AND DRIER WEATHER THEN RETURNS FOR MIDWEEK.
UPDATE
ISSUED 915 PM CDT SUN MAY 17 2026
A MATURE QLCS OVER WRN IA SHOULD REACH THE DISSIPATING STAGE
ONCE REACHING THE MS RIVER. THIS SHOULD OCCUR AS THE LARGE CAPE
AND DCAPE VALUES AND ASSOCIATED GUST FRONTS OVERWHELM THE MDT
EFFECTIVE SHEAR THAT IS PRESENT. THE CAMS SHOW GOOD AGREEMENT
WITH THIS SCENARIO. NEVERTHELESS, GUSTY WINDS AND SCATTERED
STORMS WILL CONTINUE TO INITIATE ALONG AND BEHIND THE GUST FRONT
DURING THE EARLY MORNING HOURS. MUCAPE OF 1500-2000 J/KG WILL BE
PRESENT BUT WITH HIGH LFCS AT 650-700 MB. THE HIGH LFCS SHOULD
AID IN THE DISSIPATION OF THE LINE AND/OR TRANSITIONING TO
ELEVATED SCATTERED STORMS.
DURING THIS TIME, A WAVE OF LOW PRESSURE WILL TRACK ACROSS MN
TO WRN LAKE SUPERIOR AND BE THE CATALYST TO SHIFTING THE WARM
FRONT NWD INTO CENTRAL WI. THUS THE LOW STRATUS AND AREAS OF FOG
TOWARD CENTRAL WI WILL COME TO AN END DURING THE EARLY MORNING
HOURS. SOME SHOWERS AND STORMS WILL LIKELY LINGER THROUGH MON
AM, BUT CAPPING WILL SET IN AGAIN AND WILL AID IN SOME
SCATTERING OF CLOUDS AND TEMPS NEARING 80F FOR THE AFTERNOON.
ANOTHER WAVE OF LOW PRESSURE WILL DEVELOP FROM THE CENTRAL
GREAT PLAINS TO NRN WI FROM LATE MON AFTERNOON UNTIL 12Z TUE,
WHILE THE MAIN SHORTWAVE TROUGH TRACKS FROM THE CENTRAL ROCKIES
TO NW WI. THE ACTUAL TRAILING COLD FRONT WILL LIKELY NOT PASS
UNTIL TUE, BUT THERE IS SOME CONFIDENCE IN ANOTHER ROUND OF
SHOWERS AND STORMS FOR MAINLY AFTER MIDNIGHT (EARLY TUE AM) AS
ANOTHER MCS MOVES INTO SRN WI FROM THE WEST. THE MCS MAY ALREADY
HAVE REACHED THE DISSIPATING STAGE AT THIS TIME, BUT THERE IS
UNCERTAINTY WITH THE TIMING OF THE EVOLUTION. ONCE AGAIN,
DAMAGING WIND GUSTS WOULD BE THE MAIN CONCERN.
GEHRING
SHORT TERM
ISSUED 331 PM CDT SUN MAY 17 2026
TONIGHT THROUGH MONDAY NIGHT:
WELL THE DEPARTING MCV WAS ABLE TO BRING A PART OF THE WARM INTO
SOUTHWESTERN WI AND SPUR A SUPERCELL OR TWO. HOWEVER, MUCH OF THE
ACTIVITY ASSOCIATED WITH THE MCV IS TRACKING NORTHEAST INTO
CENTRAL WI. WHILE THE ONSHORE EASTERLY FLOW OFF OF LAKE MICHIGAN
IS KEEPING THE ENVIRONMENT COOL AND SABLE AT THE SURFACE, A FEW
ELEVATED STORMS ARE TAPPING INTO THE ELEVATED ENVIRONMENT AND
MAINTAINING THEIR STRENGTH. THERE ARE HINTS OF GRAVITY WAVES IN
THIS ENVIRONMENT THAT HAVE OCCASIONALLY HELPED THESE STORMS
PUNCH STRONG WINDS TO THE SURFACE. THUS WILL SEE A GUSTY WIND
THREAT ASSOCIATED WITH THIS ACTIVITY OVER THE NEXT HOUR OR TWO
AS THE SYSTEM DEPARTS.
FOR THE AFTERNOON/EVENING FOCUS SHIFTS TOWARD THE WARM FRONT
STREWN ACROSS SOUTHWESTERN WI THROUGH NORTHERN IL. ALONG AND
SOUTH OF IT WE ARE SEEING MUCH WARMER TEMPS AND DEWPOINTS IN THE
MID 60S ALONG WITH SBCAPE +1000 J/KG. MODELS CONTINUE TO SHOW
THIS BOUNDARY LIFTING NORTH THROUGH THE LATER AFTERNOON AND
EVENING. HOWEVER THE COOLER EASTERLY WINDS MAY SLOW ITS
NORTHWARD PROGRESSION FOR SOUTHEASTERN WI AND LIMIT THE BETTER
ENVIRONMENT CLOSER TO THE LAKE. WHILE INGREDIENTS LINE UP FOR
ADDITIONAL DEVELOPMENT THROUGH THE EVENING, THE DEEP LAYER SHEAR
REMAINS A LIMITING FACTOR AS IT HANGS ON THE LOWER END OF THE
THRESHOLD (LESS THAN 40 KT). BUT GIVEN THE TRENDS TODAY AND
STRENGTH OF THIS WARM FRONT, WOULD NOT BE SURPRISED TO SEE
THUNDERSTORMS DEVELOP ALONG IT AS LATEST SATELLITE SUPPORTS MORE
PERCOLATING CU FIELD. ANYTHING THAT DOES DEVELOP ALONG AND
SOUTH OF THE FRONT WILL BE MORE SURFACE BASED AND CAPABLE OF
PRODUCING LARGE HAIL, DAMAGING WINDS, AND EVEN COULD NOT RULE
OUT A SPIN UP OR TWO GIVEN THE 20-30 KT OF LOW-LEVEL SHEAR.
HOWEVER, STORMS ARE POSSIBLE NORTH OF THE FRONT AS WELL TAPING
INTO MUCAPE 500-1000 J/KG AND WOULD BE MORE ELEVATED IN NATURE
CAPABLE OF PRODUCING HAIL AND OCCASIONALLY PUNCHING DOWN A
STRONGER GUST OR TWO.
LATER THIS EVENING/TONIGHT WILL BE ANOTHER POTENTIAL FOR SEVERE.
THIS ROUND WILL BE ASSOCIATED WITH THE LINE OF STORMS ONGOING OUT
ALONG THE NE/SD BORDER THIS AFTERNOON. THIS FEATURE IS
DEVELOPING CLOSER TO THE LOW AND ALONG THE WARM FRONT WHERE THE
BETTER DYNAMICS ALIGN. MOST MIDDAY MODELS CONTINUE TO PROG THIS
LINE TO RIDE ALONG AND SOUTH OF THE WARM FRONT EASTWARD TONIGHT
TAPPING ALONG INTO THE SURFACE BASED INSTABILITY. THIS FEATURE
LOOKS TO SUSTAIN THROUGH IA/MN AS A 40-50 KT LLJ BUILDS IN LATER
THIS EVENING/TONIGHT. THE QUESTION IS WILL THIS LINE MAINTAIN
ITS STRENGTH AS IT MOVES INTO SOUTHERN WI. WHILE CAMS CONTINUE
TO PROJECT THIS LINE TO WEAKEN AND GUST OUT AFTER CROSSING EAST
OF THE MISSISSIPPI RIVER INTO SOUTHERN WI/NORTHERN IL AFTER
MOVING AWAY FROM THE BETTER UPPER-LEVEL SUPPORT, I DO HAVE A
GROWING CONCERN THAT THE ONGOING LINE OF STORMS, WHICH IS
SHOWING SIGNS OF BECOMING A BOWING SEGMENT MAY BE ABLE TO
MAINTAIN ITSELF MORE THAN THE MODELS SUGGEST AT THE MOMENT AS IT
LOOKS TO RIDE WEST TO EAST ALONG THE SURFACE WARM FRONT AND
INSTABILITY GRADIENT. WILL ALSO HAVE THE LLJ AIDING IT AS WELL.
AT THE VERY LEAST THINK IT WILL MAINTAIN STRENGTH INTO OUR
WESTERN HALF OF THE CWA TONIGHT, BUT MAY EVENTUALLY TAP INTO THE
MORE STABLE AIRMASS PUSHED IN FROM LAKE MICHIGAN FURTHER EAST.
NEVERTHELESS, IF THE LINE IS ABLE TO CONTINUE INTO SOUTHERN WI
IT WILL LIKELY BE A LINEAR MODE WITH POTENTIAL FOR A FEW
ISOLATED DISCRETE CELLS POPPING OUT AHEAD OF IT AFTER AROUND 03Z
TIMEFRAME AND PUSH THROUGH OVERNIGHT AND MAY LINGER INTO MONDAY
MORNING, ESPECIALLY IF THINGS SLOW DOWN FURTHER.
THIS ACTIVITY DOES LOOK PUSH THROUGH BY DAYBREAK. OTHERWISE, MONDAY
IS LOOKING FAIRLY DRY, WARM, AND HUMID FOR THE DAY MONDAY. THEN
LOOKING AT ANOTHER OPPORTUNITY FOR ROUND OF SHOWERS AND STORMS LATER
MONDAY EVENING/OVERNIGHT AHEAD AND ALONG OF A COLD FRONT. CONTINUE
TO MONITOR MONDAY FOR SEVERE POTENTIAL AS SPC HAS THE AREA OUTLOOKED
WITH A SLIGHT RISK (2 OUT OF 5). WHILE THE COLD FRONT HOLD JUST TO
THE WEST DURING THE DAY, EXPECT THE UPPER-LEVEL TROUGH TO LIFT
ACROSS THE UPPER MIDWEST LATER MONDAY WIT MID-LEVEL DCVA, LOW-LEVEL
WAA AND FRONTOGENESIS MOVING THROUGH THE AREA LATER MONDAY. THUS
PLENTY OF UPPER-LEVE SUPPORT FOR STRONG TO SEVERE DEVELOPMENT. THE
QUESTION REMAINS ON WHERE THESE INGREDIENTS LINE UP AS MOST MODELS
SUGGESTS CONVECTIVE INITIATION BACK TO THE WEST ACROSS MN/IA
AND HAVE A LINE MOVE INTO SOUTHERN WI. TIMING IS THE OTHER
CONCERN AS EARLY EVENING DEVELOPMENT TO THE WEST MOVES INTO
SOUTHERN WI OVERNIGHT NOT TO DISSIMILAR FROM TONIGHT'S
ACTIVITY. SO WHILE STILL SOME UNCERTAINTY REMAINS, STILL LOOKING
TO AGREE ON A LATE EVENING/ OVERNIGHT LINE OF STORMS ACROSS THE
AREA. MAIN CONCERN WILL BE DAMAGING WINDS, ESPECIALLY WITH ANY
BOWING SEGMENTS ALONG WITH AN EMBEDDED TORNADO OR TWO. ALSO WITH
SOME LINGERING INSTABILITY AHEAD OF THE LINE COULD NOT RULE OUT
A FEW ISOLATED DISCRETE CELLS AS WELL.
REGARDLESS, STAY WEATHER AWARE TONIGHT AND TOMORROW AS THERE REMAINS
MULTIPLE WINDOWS FOR STORMS WITH POTENTIAL FOR STRONG TO SEVERE
STORMS CAPABLE OF HAIL AND GUSTY WINDS AS WELL A FEW TORNADOES.
WAGNER
LONG TERM
ISSUED 331 PM CDT SUN MAY 17 2026
TUESDAY THROUGH SUNDAY:
HEADING INTO TUESDAY MORNING, RAIN AND THUNDERSTORMS ARE EXPECTED
TO CONTINUE ACROSS MUCH OF WISCONSIN. THE TROUGH IN THE ROCKIES
WILL CONTINUE TO PULL NORTHEAST INTO THE GREAT LAKES THROUGH
TUESDAY WITH A SHORTWAVE TROUGH ALSO MOVING THROUGH THE LARGER 500
MB FLOW. GUIDANCE HAS THE UPPER LEVEL JET STRENGTHENING A BIT
TUESDAY AFTERNOON INTO WEDNESDAY EVENING. MEANWHILE AT THE SURFACE
A COLD FRONT WILL BE MOVING ACROSS THE STATE AND A SURFACE LOW
WILL BE PULLING NORTHEAST FROM NORTHERN WISCONSIN TOWARD WESTERN
QUEBEC BY WEDNESDAY. UNCERTAINTY REMAINS ON THE EXACT TIMING THAT
THIS COLD FRONT WILL MOVE THROUGH SOUTHERN WISCONSIN. TIMING WILL
PLAY A BIG ROLE ON THE STRENGTH OF ANY STORMS AND ASSOCIATED
HAZARDS. CURRENT MODEL TRENDS HAVE THIS FRONT CLEARING TO THE
SOUTHEAST BY MIDDAY TUESDAY. THE TIMING MAY BE GREAT IN PREVENTING
NEW INITIATION, BUT WITH THAT JUST AS MANY MODELS ARE HINTING AT
A POTENTIAL MCS WHICH KINDA MAKES THE WHOLE THING A WASH STRONG TO
SEVERE STORM WISE. NO MATTER THE SCENARIO THERE IS A POTENTIAL
FOR STRONGER STORMS, BUT WHAT FLUCTUATES ARE THE HAZARDS AND
LIKELIHOOD THAT THEY ACTUALLY OCCUR. HOW THIS EVENT UNFOLDS AS A
WHOLE AND HOW EACH ROUND PLAYS OUT FROM THE TIME THE WARM FRONT
MOVES IN MONDAY TO WHEN THE COLD FRONT EXITS TUESDAY WILL MATTER.
THE MORE OVERWORKED THE ENVIRONMENT BECOMES WITH LITTLE TIME FOR
RECOVERY IN BETWEEN WILL GENERALLY MEAN WEAKER STORMS. GIVEN THE
UNCERTAINTIES HERE THIS WILL BE A CRITICAL PERIOD TO KEEP UP TO
DATE WITH THE FORECAST SO YOU DON'T GET CAUGHT OFF GUARD.
BEYOND THIS LOOKING TOWARD MID-WEEK, HIGH PRESSURE WITH COOLER AND
DRIER AIR IS EXPECTED TO MOVE THROUGH BRINGING DRY WEATHER
WEDNESDAY AND THURSDAY. DAYTIME HIGHS ARE EXPECTED TO BE AT THE
COOLEST WEDNESDAY IN THE LOW 50S TO LOW 60S (THE COOLER LOW 50S
ARE EXPECTED NEAR LAKE MICHIGAN). SLIGHTLY WARMER CONDITIONS ARE
EXPECTED INLAND THURSDAY, BUT EASTERLY FLOW OF THE LAKE WILL KEEP
TEMPS CAPPED IN LOW 50S TO MID 60S AREA WIDE (AGAIN COOLER AT THE
LAKESHORE).
FRIDAY INTO SATURDAY LOOKS LIKE THE NEXT POTENTIAL FOR RAIN AND
STORMS. CHANCES ARE STILL FAIRLY LOW HERE AROUND 10-20%. THIS IS
LARGELY DUE TO UNCERTAINTY IN THE STRENGTH AND LOCATION OF AN
UPPER LEVEL TROUGH THAT WILL MOVE FROM ALBERTA TO FAR NORTHER
PLAIN. MODELS ARE SPLIT ON HOW FAR EAST THIS TROUGH WILL GET
BEFORE IT SWINGS BACK NORTHEAST INTO ONTARIO/QUEBEC. GIVEN THAT I
WOULDN'T BE SHOCKED TO SEE TRENDS KEEP THE LOW POPS IN PLACE UNTIL
THERE IS ENOUGH CONFIDENCE THAT THIS SYSTEM TRACK. THE ONE BRIGHT
SIDE IS THOSE HOPPING FOR SOME MORE SUMMER LIKE TEMPERATURES MAY
GET JUST THAT AS WINDS BECOME SOUTHERLY AGAIN FOR THE WEEKEND.
PATTERSON
AVIATION
ISSUED 915 PM CDT SUN MAY 17 2026
STRATUS BELOW 1 KFT AND AREAS OF FOG ARE OCCURRING TOWARD
CENTRAL WI THIS EVENING, BUT VFR CONDITIONS WILL RETURN LATE
TNT ONCE THE WARM FRONT PASSES TO THE NORTH. SCATTERED
THUNDERSTORMS WITH GUSTY WINDS WILL THEN MOVE ACROSS MUCH OF SRN
WI DURING THE EARLY MORNING HOURS WITH SOME SHOWERS AND STORMS
CONTINUING THROUGH SUN AM. SCT-BKN040-060 CLOUDS ARE EXPECTED
DURING THIS TIME BUT AREAS OF MVFR CIGS MAY OCCUR. ANOTHER ROUND
OF THUNDERSTORMS AND GUSTY WINDS IS THEN FORECAST LATE MON NT
WITH MORE MVFR CIGS POSSIBLE.
GEHRING
MARINE
ISSUED 915 PM CDT SUN MAY 17 2026
A WARM FRONT WILL MOVE FROM SOUTHERN LAKE MICHIGAN TO NORTHERN
LAKE MICHIGAN THROUGHOUT THE NIGHT. EAST TO NORTHEAST WINDS WILL
BECOME BREEZY OUT OF THE SOUTH. AREAS OF DENSE FOG MAY OCCUR AT
TIMES UNTIL THE FRONT PASSES. BREEZY SOUTH WINDS WILL THEN
CONTINUE THROUGH MONDAY AND INTO TUESDAY FOLLOWED BY A WIND SHIFT
TO THE NORTHWEST LATE TUESDAY AFTERNOON AND EVENING WITH THE
PASSAGE OF A COLD FRONT. HIGH PRESSURE AND LIGHT AND VARIABLE
WINDS WILL THEN TAKE HOLD FROM LATE WEDNESDAY INTO THURSDAY.
A MARINE DENSE FOG ADVISORY IS IN EFFECT FROM SHEBOYGAN TO NORTH
POINT LIGHTHOUSE UNTIL 3 AM CDT MONDAY. THE FOG WILL DISSIPATE
ONCE THE WARM FRONT MOVES TO THE NORTH, AND SOUTH WINDS AND
MILDER TEMPERATURES ARRIVE.
GEHRING
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...DENSE FOG ADVISORY...LMZ643-LMZ644 UNTIL 3 AM MONDAY.
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