932
FXUS63 KARX 161821
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
121 PM CDT SUN AUG 16 2026
KEY MESSAGES
- DRIER WITH NEAR NORMAL TEMPERATURES FOR TODAY AND MONDAY.
- SHOWER AND STORM POTENTIAL RETURNS MONDAY NIGHT AND AGAIN
TUESDAY AFTERNOON INTO WEDNESDAY MORNING, THOUGH THE HIGHER
CHANCES FOR RAIN HAVE BEEN TRENDING SOUTH.
- PERIODIC CHANCES FOR RAIN CONTINUES THROUGH THE REST OF THE WORK
WEEK ALONG WITH MILD AFTERNOON HIGHS.
DISCUSSION
ISSUED AT 119 PM CDT SUN AUG 16 2026
REST OF TODAY AND MONDAY: DRY WITH MILD TEMPERATURES
WESTERLY FLOW ALOFT IS FORECAST TO PREVAIL TODAY THROUGH MONDAY
ACROSS THE UPPER MIDWEST. IN THE WAKE OF THE FRONTAL PASSAGE THIS
MORNING, DRIER AIR HAS MOVED IN OVER THE REGION, ESPECIALLY AT THE
SURFACE. EVEN WITH COOLING TEMPERATURES AT H850 TODAY, THE AFTERNOON
HIGHS SHOULD BE ABLE TO REACH THE UPPER 70S TO LOW 80S WITH THE
SURFACE WIND OUT OF THE NORTHWEST. GIVEN THE SOMEWHAT DRIER AIR AT
THE SURFACE, TEMPERATURES TONIGHT SHOULD BE ABLE TO DROP INTO THE
LOWER 60S TO 50S. LIGHT WIND AND A SHALLOW MOIST LAYER AT THE
SURFACE MAY LEAD TO FOG ACROSS PORTIONS OF THE CWA ON MONDAY
MORNING, ESPECIALLY FOR AREAS IN WISCONSIN. VERY SIMILAR CONDITIONS
ARE EXPECTED ON MONDAY WITH HIGHS IN THE UPPER 70S TO LOW 80S WITH
LIGHT WINDS.
MONDAY NIGHT THROUGH WEDNESDAY MORNING: SHOWER AND THUNDERSTORM
POTENTIAL
MID LEVEL MOISTURE MOVES BACK OVER THE UPPER MISSISSIPPI RIVER
VALLEY LATE MONDAY AFTERNOON THROUGH TUESDAY. AS THIS OCCURS, A
SHORTWAVE EMBEDDED IN THE WESTERLY FLOW ALOFT WILL MOVE OVER THE
REGION. THE COMBINATION OF THESE FEATURES SHOULD LEAD TO SCATTERED
SHOWER AND THUNDERSTORM DEVELOPMENT. SEVERE THUNDERSTORMS ARE NOT
ANTICIPATED WITH THIS ACTIVITY SINCE FORECAST SOUNDINGS ONLY DEPICT
A FEW HUNDRED JOULES OF CAPE THROUGHOUT THE ATMOSPHERIC PROFILES.
ANY SHOWER OR THUNDERSTORM ACTIVITY THAT DOES DEVELOP AND MOVE
EAST/SOUTHEAST OVER THE AREA SHOULD DISSIPATE ON TUESDAY MORNING
ACROSS WESTERN INTO CENTRAL WISCONSIN.
AFTER A BRIEF BREAK IN THE RAIN CHANCES MID DAY ON TUESDAY, ANOTHER
ROUND WILL BE POSSIBLE ON TUESDAY AFTERNOON INTO WEDNESDAY MORNING
AS THE BASE OF THE H300 TROUGH DIGS SOUTH OVER THE MIDWEST.
UNFORTUNATELY FOR THOSE ACROSS NORTHERN WISCONSIN AND THE NORTHERN
PORTIONS OF THE FORECAST AREA, THE BETTER CHANCES (40-70 PERCENT)
FOR RAIN CONTINUE TO TREND TOWARDS THE SOUTHERN HALF OF THE AREA AND
MORESO INTO IOWA. THE LATEST 16/13Z NBM CONTINUES TO SHOW THIS TREND
IN THE PROBABILITY FOR 1 INCH OF RAIN OR MORE, WHICH NOW SHOWS THE
HIGHEST CHANCE IS ONLY UPWARDS OF 30 PERCENT ACROSS NORTHEASTERN
IOWA. THAT PERCENTAGE IS DOWN FROM 45-50 PERCENT THAT THE NBM HAD
YESTERDAY AT THIS TIME. EVEN THOUGH THE HEAVIER RAIN POTENTIAL
CONTINUES TO SHIFT SOUTH, THE POTENTIAL FOR A STORM OR TWO BECOME
SEVERE REMAINS ACROSS MAINLY NORTHEASTERN IOWA INTO SOUTHWESTERN
WISCONSIN ON TUESDAY AFTERNOON INTO THE EARLY EVENING. CONFIDENCE IS
QUITE LOW IN THAT POTENTIAL AT THIS TIME, ESPECIALLY GIVEN
INCONSISTENCIES IN THE MODEL GUIDANCE AS TO WHERE THE BETTER LIFT
PROVIDED BY THE SHORTWAVE WILL ACTUALLY MOVE OVER. SHOWERS AND
STORMS MAY LINGER INTO EARLY WEDNESDAY MORNING ACROSS THE FAR SOUTH.
THURSDAY TO NEXT WEEKEND: PERIODIC RAIN CHANCES WITH MILD CONDITIONS
NORTHWEST FLOW ALOFT IS FORECAST BEYOND WEDNESDAY AS TROUGHING
REMAINS OVER THE EASTERN CONUS WITH A RIDGE OVER THE INTERMOUNTAIN
WEST. THIS PATTERN WILL LIKELY ALLOW SHORTWAVES TO MOVE OVER THE
AREA DURING THIS TIME FRAME LEADING TO PERIODS OF SHOWERS AND
STORMS, BUT TIMING DIFFERENCES LEADS TO LOW CONFIDENCE IN WHERE AND
WHEN ANY RAIN OCCURS AT THIS TIME. TEMPERATURES SHOULD REMAIN AROUND
TO SLIGHTLY BELOW AVERAGE GOING INTO NEXT WEEKEND.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1231 PM CDT SUN AUG 16 2026
PRIMARY FOCUS OVER THE NEXT 24 HOURS IS POTENTIAL FOR IFR/LIFR
FOG/STRATUS OVERNIGHT TONIGHT AS RELATIVELY DAMP POST-FRONTAL
CONDITIONS ARE PRESENT AT ISSUANCE, AS EVIDENCED BY THE
WIDESPREAD STRATOCUMULUS AT OR AROUND 3500 FT, AND WINDS
OVERNIGHT WILL DECREASE CONSIDERABLY. LATEST GUIDANCE SUGGESTS
LIGHT WIND LAYER WILL BE DEEP ENOUGH TO FAVOR FOG RATHER THAN
STRATUS WITH THIS MORE PROBABLE TO DEVELOP ACROSS WISCONSIN,
INCLUDING AT LSE. HAVE ONLY INCLUDED A FEW HOURS IN THE TAF AS
LIGHT WIND LAYER IS SHALLOWER THAN OPTIMAL FOR A CLASSIC RIVER
VALLEY FOG EVENT. CONFIDENCE THAT THIS WOULD SPREAD AS FAR WEST
AS RST WAS TOO LOW (20%) FOR INCLUSION WITH THIS CYCLE.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...MUSCHA
AVIATION...FERGUSON
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