300
FXUS63 KMKX 160614
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
114 AM CDT TUE JUN 16 2026
KEY MESSAGES
- SHOWERS (60-85 PERCENT CHANCE) AND SCATTERED THUNDERSTORMS
THIS AFTERNOON. SMALL HAIL EXPECTED WITH THE THUNDERSTORMS.
- WIDESPREAD SHOWERS (80-90 PERCENT CHANCE) AND SCATTERED
THUNDERSTORMS WEDNESDAY AND WEDNESDAY NIGHT. HEAVY RAIN AND A
CONDITIONAL THREAT FOR SEVERE THUNDERSTORMS IS FORECAST.
- WINDS AND WAVES MAY APPROACH SMALL CRAFT ADVISORY CRITERIA
WEDNESDAY AFTERNOON INTO THURSDAY.
- NEXT NOTEWORTHY CHANCE FOR THUNDERSTORMS IS SUNDAY.
SHORT TERM
ISSUED 100 AM CDT TUE JUN 16 2026
TODAY THROUGH WEDNESDAY NIGHT:
THROUGH THE PREDAWN HOURS TODAY, A COMPACT SHORTWAVE IS EXPECTED
TO TRACK SOUTHEAST FROM MN INTO NORTHWEST WI, INDUCING A NARROW
LLJ OVER EASTERN IA AND SOUTHERN WI. THE ASSOCIATED WAA MAY
DEVELOP SOME WIDELY SCATTERED RAINSHOWERS (OR EVEN WEAK
THUNDERSTORMS) IN THE REGION BETWEEN ROUGHLY 3 AM AND 9 AM THIS
MORNING. A LULL IN THE SHOWER ACTIVITY WOULD THEN BE LIKELY
LATE THIS MORNING AS THIS ACTIVITY PUSHES EAST OVER LAKE
MICHIGAN.
THE SHORTWAVE TROUGH CLOSES OFF INTO A COMPACT UPPER LOW OVER
CENTRAL PORTIONS OF WI THROUGHOUT THE DAY TODAY, SLOWLY TRACKING
EAST. THE RELATIVELY COOL AIR ALOFT, PREEXISTING MODEST MID-LEVEL
LAPSE RATES, AND SHARPENING LOW-LEVEL LAPSE RATES (THROUGH THE
COURSE OF DAYTIME HEATING) SHOULD ALLOW THIS FEATURE TO PRODUCE A
SECOND ROUND OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON
(NOON-7PM), THIS TIME WITH GREATER COVERAGE. THE RELATIVELY LOW
FREEZING LEVELS (BENEATH 8,000 FT AT TIMES) SHOULD ALLOW ANY
THUNDERSTORM CELLS TO PRODUCE SMALL HAIL. DRY WEATHER RETURNS
THIS EVENING.
AS ANOTHER 500MB TROUGH TRACKS SOUTHEASTWARD ACROSS THE DAKOTAS
TONIGHT, DIFFLUENT FLOW OVERSPREADS IOWA AND AN MCS EVOLVES. 00Z
MODEL GUIDANCE DEPICTS THIS MCS TRACKING EASTWARD INTO SOUTHERN
WI AND MUCH OF IL, ARRIVING BETWEEN 5-9 AM WEDNESDAY MORNING.
WITH HREF MEAN MUCAPE UNDER 1,000 JOULES IN OUR REGION AND
SUBSTANTIALLY HIGHER INTO IA/IL, IT WOULD APPEAR THAT THE
MAJORITY OF THE STRONGER / SEVERE STORMS WILL DIVE SOUTH OF OUR
REGION, LEAVING SUB-SEVERE STORMS (STILL PLENTY CAPABLE OF
LIGHTNING AND POSSIBLY BRIEF HEAVY RAINFALL) TO OVERSPREAD OUR
REGION WEDNESDAY MORNING.
DEEP SURFACE LOW PRESSURE BEHIND THE MCS WILL THEN ATTEMPT TO
DRAW THE EFFECTIVE WARM FRONT (AND INSTABILITY PLUME) NORTHWARD
INTO FAR SOUTHERN WI WEDNESDAY AFTERNOON. THE 00Z HREF'S BEST
GUESS IS THAT THE WARM FRONT WILL SETUP JUST SOUTH OF THE WI/IL
BORDER AND SHIELD US FROM SURFACE BASED CONVECTION (AND THUS
REDUCE SEVERE WX POTENTIAL), BUT AS STATED DURING THE PRIOR
FORECAST ITERATION, A SMALL SHIFT IN THE MCS OR LOW PRESSURE
SYSTEM TRACK COULD STILL BRING THE WARM FRONT AS FAR NORTH AS
SOUTHERN WI, YIELDING AN ALL-HAZARDS SEVERE THREAT SOUTH OF THE
I-94 CORRIDOR. STAY TUNED TO THIS FORECAST, AS DETAILS CAN AND
WILL CHANGE.
SHEPPARD
LONG TERM
ISSUED 100 AM CDT TUE JUN 16 2026
THURSDAY THROUGH MONDAY:
PREDOMINANTLY DRY WEATHER EXPECTED IN THE COOL SECTOR OF THE
DEPARTING LOW PRESSURE ON THURSDAY. SOME LINGERING 500MB VORTICITY
ON THE NORTH EDGE OF THE JET, SOME COOL AIR ALOFT, AND STEEPENING
LOW-LEVEL LAPSE RATES THROUGH THE COURSE OF DIURNAL HEATING (BELOW
THE SUBSIDENCE INVERSION) ALLOWS MODELS TO YIELD SOME LOW CHANCES
OF CELLULAR RAIN SHOWERS THURSDAY (~10-15% CHANCE). A SIMILAR
STORY FOR FRIDAY, NOT ENOUGH JET DYNAMICS TO SUPPORT MUCH ELSE.
ENSEMBLE PLOTS FOR HIGH TEMPS SUGGEST A DAYTIME HIGH AROUND 70 /
LOW 70S FOR THURSDAY, WITH ONLY A VERY SLIGHT OVERALL WARMING
TREND THIS WEEKEND INTO EARLY NEXT WEEK (ENSEMBLE MEAN HIGH
TEMPS CENTERED IN THE MID 70S, WITH GROWING DISPERSION).
FOR SATURDAY, THE LONGWAVE TROUGH AXIS CENTERED OVER OUR REGION
BEGINS TO EXIT EAST (HENCE THE SLIGHT WARMING TREND). WARM/MOIST
RETURN FLOW OVER THE GREAT PLAINS SETS UP A NW TO SE ORIENTED
BAROCLINIC ZONE FROM SOUTHERN MN INTO EASTERN IA / NORTHWEST IL
(AND PERHAPS SOUTHERN WI), WHICH LEAVES THE POTENTIAL FOR A
RIDGE-RIDING SHORTWAVE TO KICK-OFF AN MCS FRIDAY NIGHT AND TRACK
IT ALONG THAT GRADIENT TOWARDS OUR REGION SATURDAY MORNING. THE
MODELS (FOR NOW) SUGGEST THAT THE GRADIENT AND MCS (AS SEEN IN QPF
OUTPUT) WILL SETUP SOUTHWEST OF US, THOUGH WE HAVE SOME 20-30%
PRECIP CHANCES ACROSS OUR CWA JUST IN CASE.
OUR NEXT NOTEWORTHY CHANCE FOR THUNDERSTORMS ARRIVES SUNDAY, WITH
PLENTY OF UNCERTAINTY AS TO HOW THINGS WILL SHAKE OUT. MULTIPLE
ECMWF ENSEMBLE MEMBERS TRACK AN ORGANIZED LOW PRESSURE SYSTEM
NORTHEAST FROM THE CENTRAL PLAINS TOWARDS SOUTHERN WI (A SETUP
WHICH WOULD LEAVE ORGANIZED THUNDERSTORM CHANCES ON THE TABLE),
WHEREAS SEVERAL GEFS MEMBERS TRACK THE LOW THROUGH ILLINOIS,
LEAVING US WITH NO SOUTHERLY RETURN FLOW. A LARGE SUBSET OF
MEMBERS FROM EACH MODELING SYSTEM STALLS THE LOW OVER THE CENTRAL
PLAINS, LEAVING THE BAROCLINIC ZONE NORTHEAST OF IT AND ANY
CORRESPONDING SATELLITE LOW PRESSURE TO ATTEMPT A NORTHWARD PUSH
OF MOISTURE / QPF INTO OUR REGION. ALL THIS TO SAY THE
PREDICTABILITY IS VERY LOW, BUT THERE ARE CHANCES FOR SHOWERS
AND THUNDERSTORMS SUNDAY.
SHEPPARD
AVIATION
ISSUED 100 AM CDT TUE JUN 16 2026
VFR AND LIGHT SOUTHWEST WINDS EXPECTED FOR THE NEXT FEW HOURS.
AS A SHORTWAVE TROUGH SAGS SOUTHEASTWARD FROM MN INTO WI, A
NARROW WSW LLJ IS EXPECTED TO PRODUCE 35-40KT WINDS AT THE
2,000FT LEVEL EARLY THIS MORNING OVER PORTIONS OF SOUTHERN WI,
YIELDING A BRIEF WINDOW OF LLWS (INCLUDED IN THE KMSN, KUES, AND
KJVL TAFS). THIS SAME FEATURE MAY KICK-START SOME WIDELY
SCATTERED SHOWERS OR EVEN WEAK THUNDERSTORMS, WITH PROB30 GROUPS
INCLUDED IN THE TAFS EARLY THIS MORNING AS IT PASSES. VFR
CEILINGS EXPECTED WITH THIS ACTIVITY.
THE AFOREMENTIONED SHORTWAVE TROUGH CONTINUES IT'S PROGRESSION
INTO CENTRAL WI THIS AFTERNOON, WITH SCATTERED SHOWERS EXPECTED
AND A CHANCE FOR THUNDERSTORMS. THESE STORMS ARE GENERALLY
EXPECTED TO BE SUB-SEVERE, BUT COULD EASILY PRODUCE SMALL HAIL
(DUE TO THE COLD AIR ALOFT). GENERALLY VFR CEILING ALTITUDES
WITH THIS ACTIVITY, BUT CANNOT RULE OUT SOME BRIEF MVFR
CEILINGS. VISIBILITY MAY DROP TO MVFR (OR EVEN BRIEFLY IFR) WITH
THE HEAVIEST SHOWERS / STORMS.
SHEPPARD
MARINE
ISSUED 100 AM CDT TUE JUN 16 2026
SOUTHWESTERLY WINDS SHIFT SOUTHERLY EARLY THIS MORNING AS A LOW
PRESSURE SYSTEM DEEPENS OVER NORTHERN LAKE MICHIGAN (29.5
INCHES). WINDS BECOME RELATIVELY LIGHT AND VARIABLE UNDERNEATH
IT (NORTHERN HALF OF THE LAKE) LATER THIS AFTERNOON, WITH WINDS
VEERING WEST OVER THE SOUTHERN HALF. SHOWERS AND THUNDERSTORMS
WILL BE POSSIBLE ACROSS THE LAKE THROUGH THE DAYTIME HOURS
TODAY, A COUPLE OF STRONGER CELLS THIS AFTERNOON COULD PRODUCE
SMALL HAIL.
A WEAK SURFACE RIDGE CROSSES THE LAKE TONIGHT, WITH WINDS
SUBSIDING AND BACKING SOUTHWEST. A MUCH MORE ORGANIZED LOW
PRESSURE SYSTEM (29.2 INCHES) WILL THEN TRACK EASTWARD FROM
AROUND SOUTH DAKOTA, CROSSING LAKE MICHIGAN WEDNESDAY EVENING.
AHEAD OF IT'S ARRIVAL, WE EXPECT GUSTY SOUTHEAST WINDS WEDNESDAY
MORNING AND AFTERNOON (PARTICULARLY OVER THE SOUTHERN HALF OF
THE LAKE) WITH INCREASING CHANCES FOR THUNDERSTORMS, SOME OF
WHICH COULD BE STRONG (PARTICULARLY OVER FAR SOUTHERN PORTIONS
OF THE LAKE). BREEZY WEST TO NORTHWEST WINDS ARE EXPECTED
WEDNESDAY NIGHT INTO THURSDAY AS THE LOW EXITS EAST. THIS SAME
BREEZE THEN CONTINUES INTO FRIDAY (ALBEIT WEAKER) AS WEAK HIGH
PRESSURE BUILDS INTO THE REGION FROM THE WEST.
SHEPPARD
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
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