782
FXUS63 KMKX 222001
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
301 PM CDT TUE JUN 22 2021
SHORT TERM
(ISSUED 300 PM CDT TUE JUN 22 2021)
TONIGHT THROUGH WEDNESDAY NIGHT:
A SURFACE RIDGE EXTENDING NORTHWARD INTO OUR AREA WILL BEGIN TO
BREAK DOWN AS HIGH PRESSURE CENTERED OVER THE MIDDLE MISSISSIPPI
VALLEY REGION SHIFTS EASTWARD THIS EVENING. AS THIS HIGH PRESSURE
SHIFTS EAST, WINDS WILL COME AROUND TO SOUTHERLY AND WAA WILL
INCREASE AS A WARM FRONT DRAPED FROM WEST TO EAST OVER IOWA
APPROACHES THE WI/IL BORDER. CONVECTION IS EXPECTED TO FORM ALONG
THIS FRONT LATE IN THE AFTERNOON OVER IOWA. WHILE THE SURFACE FRONT
MAY WASH OUT SOME TIME DURING THE EVENING HOURS, CONVECTION IS
EXPECTED TO RIDE THE 925 TO 850MB WAA AND ENHANCED CONVERGENCE AT
THE TIP OF THE LLJ OVERNIGHT INTO OUR AREA, BRINGING SOME CHANCES
FOR RAIN DURING THE EARLY MORNING HOURS FOR ALL OF SOUTHERN
WISCONSIN, WITH BETTER CHANCES TOWARD THE WI/IL BORDER. THE WAA
LOOKS LIKE IT WILL GROW SOMEWHAT WEAK AS IT NOSES INTO SOUTHERN WI
AND MODEL MUCAPE IS ALMOST NON-EXISTENT OVER SOUTHERN WISCONSIN, SO
CHANCES FOR SEVERE THUNDERSTORMS ARE NIL AND EVEN CHANCES FOR THE
OCCASIONAL RUMBLE OF THUNDER LOOK LOW.
SHOWERS WILL CONTINUE THROUGH THE MORNING HOURS ON WEDNESDAY AS A
SECONDARY 850MB SPEED MAX NOSES INTO SOUTHERN WISCONSIN JUST AFTER
DAWN. MODELS DEPICT SHOWER ACTIVITY CEASING DURING THE EARLY
AFTERNOON AS THE NOSE OF THE SPEED MAX SHIFTS EASTWARD OVER LOWER
MICHIGAN. SUBSIDENCE FROM A BUILDING RIDGE ALOFT SHOULD THEN ALLOW
CLOUDS TO CLEAR BRIEFLY LATE IN THE AFTERNOON THROUGH THE EARLY
EVENING BEFORE CLOUDS INCREASE AHEAD OF AN APPROACHING FRONTAL
BOUNDARY.
OVERALL, TEMPERATURES SHOULD BEGIN TO MODERATE DURING THE SHORT-TERM
PERIOD OWING TO THE INCOMING WAA. LOWS WILL BE IN THE MID-50S
TONIGHT AND THE MID-60S TOMORROW NIGHT. DAYTIME HIGHS ON WEDNESDAY
WILL BE IN THE UPPER 70S, BUT LIKELY HELD BACK FROM BEING WARMER BY
THE SHOWER ACTIVITY AND LINGERING CLOUD COVER.
CMILLER
LONG TERM
(ISSUED 300 PM CDT TUE JUN 22 2021)
THURSDAY THROUGH TUESDAY:
THE AM LONG-TERM DISCUSSION MENTIONED MODEL DISAGREEMENT AND THAT
PROBLEM LARGELY STILL PERSISTS IN THE EXTENDED PERIOD AFTER SOME NEW
MORNING MODEL RUNS. A RAINY, ACTIVE PERIOD THURSDAY THROUGH
SATURDAY, LOOKS TO REMAIN ON TRACK, HOWEVER.
SYNOPTICALLY, LOW PRESSURE OVER THE HUDSON BAY REGION IN CANADA WILL
DRAG A COLD FRONT OVER THE NORTHERN PLAINS ON WEDNESDAY. THURSDAY
MORNING, THIS FRONT LOOKS TO STALL OR AT LEAST SLOW DOWN AS IT
ENCOUNTERS THE INFLUENCE OF BROAD HIGH PRESSURE OVER THE EASTERN
SEABOARD. AS A RESULT, THE FRONT WILL BE PARKED OVER PARTS OF NW
WI AND CENTRAL MN. AS THIS FRONT SLOWLY SLIDES SE THURSDAY THROUGH
FRIDAY, MULTIPLE ROUNDS OF STORMS WILL FORM ALONG THIS FRONT AND
THEN COME OFF OF IT, DRIVEN BY THE UPPER LEVEL FLOW. THE UPSIDE
FOR THIS EVENT IS THAT WIDESPREAD RAIN APPEARS LIKELY AND AT LEAST
AN INCH SEEMS ASSURED FOR MUCH OF THE AREA THROUGH SATURDAY
AFTERNOON WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE. THE DOWNSIDE
IS THAT THE EVOLUTION OF THE SEVERE THREAT IN ASSOCIATION WITH
THIS COLD FRONT IS UP IN THE AIR THIS EARLY IN THE WEEK, AND WILL
BE CONTINGENT UPON HOW MUCH SUN WE RECEIVE ON THURSDAY AND FRIDAY
AND TIMING OF ANY OF THE MYRIAD OF CONVECTIVE COMPLEXES MODELS
DEPICT. TRENDS WILL BE MONITORED.
BEYOND, MODELS CONTINUE TO SHOW AN MORE ACTIVE PATTERN GOING
FORWARD INTO NEXT WEEK.
CMILLER
AVIATION
(ISSUED 300 PM CDT TUE JUN 22 2021)
CU AND AREAS OF MID-LEVEL STRATOCU WILL LINGER UNTIL THE LATE
AFTERNOON AND EARLY EVENING WHEN WE LOSE OUR DAYTIME HEATING.
WE'LL CLEAR OUR FOR A FEW HOURS AND WINDS WILL SLACKEN SOME, THEN
CLOUDS WILL INCREASE AGAIN AS AN AREA OF WARM AIR ADVECTION
APPROACHES FROM THE SOUTHWEST. WINDS WILL TURN SOUTHERLY DURING
THIS TIME AS WELL AND BECOME MODESTLY GUSTY AGAIN. SOME SCATTERED
SHOWER ACTIVITY IS ANTICIPATED WITH THIS WAA, AND WILL MAINLY
OCCUR DURING THE EARLY MORNING HOURS AND THROUGH THE POST-DAWN
HOURS FOR MUCH OF SOUTHERN WISCONSIN. MOST AREAS SHOULD EXPERIENCE
VFR CONDITIONS FOR THE REST OF THIS AFTERNOON AND INTO TOMORROW,
BUT A FEW INLAND LOCATIONS COULD SEE SOME MVFR CEILINGS EARLY
WEDNESDAY MORNING, OWING TO SOME OF THE BETTER MOISTURE BROUGHT IN
ON THE WAA. VISIBILITY DROPS WILL ALSO BE POSSIBLE WITH ANY
SHOWER.
CMILLER
MARINE
(ISSUED 300 PM CDT TUE JUN 22 2021)
HIGH PRESSURE OF 30.1 INCHES WILL SLIDE EASTWARD THROUGH THE
OVERNIGHT HOURS AND SETTLE INTO MIDDLE APPALACHIA BY WEDNESDAY
MORNING. AS THIS HAPPENS, WESTERLY WINDS WILL BECOME SOUTHERLY
TONIGHT. THEY'LL REMAIN MODESTLY GUSTY, HOWEVER AS THERE WILL BE A
LOW-LEVEL WIND SPEED MAX ABOVE A SHALLOW INVERSION. GOING INTO THE
DAYTIME HOURS TOMORROW, LOW PRESSURE OF 29.3 INCHES WILL APPROACH
THE HUDSON BAY REGION IN CANADA. THIS WILL STEEPEN THE PRESSURE
GRADIENT BETWEEN THE LOW PRESSURE NORTH AND THE HIGH PRESSURE TO
THE SOUTHEAST. AS A RESULT WINDS WILL STRENGTHEN THROUGH THE DAY
ON WEDNESDAY AND INTO THE OVERNIGHT HOURS ON THURSDAY. WINDS TO
GALE FORCE LOOK POSSIBLE FOR THE NORTHERN END OF THE LAKE FOR A
BRIEF PERIOD EARLY THURSDAY MORNING.
SHOWERS AND A RUMBLE OF THUNDER OR TWO WILL BE POSSIBLE OVER
NORTHERN END OF THE LAKE LATE THIS AFTERNOON, AND THEN OVER THE
SOUTHERN HALF OF THE LAKE TONIGHT INTO WEDNESDAY MORNING. BETTER
CHANCES FOR WIDESPREAD, STRONGER STORMS LOOK POSSIBLE ON THURSDAY.
LOCALLY, WINDS MAY BLOW TO SMALL CRAFT ADVISORY CRITERIA WEDNESDAY
AFTERNOON AND INTO THURSDAY MORNING OWING TO THE AFOREMENTIONED
SHARP PRESSURE GRADIENT.
CMILLER
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
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