320
FXUS63 KARX 141845
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
145 PM CDT FRI AUG 14 2026
KEY MESSAGES
- SCATTERED SHOWERS AND SOME STORMS (40 TO 60%) LATER THIS
AFTERNOON AND EVENING. THE HEAVY RAIN THREAT CONTINUES TO PUSH
FURTHER SOUTH AS THERE IS A 10 TO 25% CHANCE OF 1" OR MORE OF
RAIN.
- MORE SHOWERS AND STORMS ARE POSSIBLE (20 TO 40%) SATURDAY
AFTERNOON AND EVENING ALONG A COLD FRONT.
- AFTER DRY CONDITIONS FOR SUNDAY AND MONDAY, WIDESPREAD STORM
CHANCES RETURN TUESDAY (50 TO 80%).
DISCUSSION
ISSUED AT 144 PM CDT FRI AUG 14 2026
TODAY - SATURDAY: HEAVY RAIN TRENDING SOUTH
LOOKING AT CURRENT OBSERVATIONS AND SATELLITE ANALYSIS, THERE IS AN
MCV THAT IS SITUATED OVER WESTERN IOWA WITH A BOUNDARY POSITIONED
OVER NORTHERN IOWA. THIS BOUNDARY WILL GRADUALLY SHIFT NORTHWARD
THROUGH THE AFTERNOON AND EVENING. THE MCV WILL MOVE EASTWARD
PROVIDING CENTRAL AND EASTERN IOWA WITH A CHANCE FOR SEVERE STORMS.
AS FOR THE BOUNDARY ACROSS NORTHERN IOWA, THIS WILL PROVIDE THE AREA
WITH SCATTERED SHOWERS AND SOME RUMBLES OF THUNDER DURING THE LATER
AFTERNOON AND EVENING HOURS. THE MAJORITY OF THE INSTABILITY STAYS
IN IOWA, SO NORTHEAST IOWA HAS THE BEST CHANCE (20 TO 40%) FOR A
THUNDERSTORM DEVELOPING THIS AFTERNOON AND EVENING. THE TREND FOR
ANY HEAVY RAIN HAS CONTINUED TO SHIFT FURTHER SOUTH AS THE AXIS OF
HEAVY RAIN IS NOW MORE ALONG I-80. WHILE THE ERO MAY HAVE A SLIGHT
RISK FOR EXCESSIVE RAINFALL THIS EVENING AND EARLY OVERNIGHT, THE
CHANCES FOR THIS HAPPENING CONTINUE TO DWINDLE GIVEN THAT THE BETTER
FORCING WILL REMAIN OUT OF OUR FORECAST AREA. THE MCV WILL MOVE
EASTWARD ACROSS CENTRAL IOWA AND AS THE LLJ INCREASES THIS EVENING,
WILL PROVIDE WIDESPREAD HEAVY RAINFALL FOR EASTERN IOWA AND WESTERN
ILLINOIS. A FEW DAYS AGO THERE WAS HIGHER POTENTIAL FOR THIS BAND OF
HEAVY RAIN TO IMPACT NORTHEAST IOWA AND SOUTHWEST WISCONSIN, HOWEVER
SIMILAR TO EACH OF THE MCS'S THAT HAVE WENT SOUTH OF THE FORECAST
AREA, THIS TOO HAS TRENDED FURTHER SOUTH.
SOME LEFTOVER SHOWERS ARE POSSIBLE (10 TO 20%) FOR THE MORNING AND
EARLY AFTERNOON, BUT THE BETTER CHANCES FOR RAIN ON SATURDAY ARRIVE
WITH A COLD FRONT DURING THE LATE AFTERNOON/EARLY EVENING.
INSTABILITY INCREASES AS 1000 TO 1500 J/KG OF MUCAPE BUILD INTO THE
REGION SO SHOWERS AND ISOLATED STORMS WILL BE POSSIBLE DURING THIS
TIMEFRAME. THERE IS A LITTLE UNCERTAINTY ON THE EXACT COVERAGE OF
STORMS ALONG THIS FRONT, BUT FOR RIGHT NOW THE COVERAGE LOOKS TO BE
MORE ISOLATED (20 TO 40%) FOR SHOWERS AND STORMS. GIVEN THE
INSTABILITY AND WEAKER SHEAR, IF ANY STRONGER STORM DEVELOPS, THERE
MAY BE SOME STRONG OUTFLOW WINDS FROM THESE STORMS.
SUNDAY - MIDWEEK: DRY EARLY, MORE STORM CHANCES BY TUESDAY
ZONAL FLOW BECOMES THE DOMINANT FLOW PATTERN THROUGH MIDWEEK. A
SURFACE HIGH PASSES THROUGH THE UPPER MIDWEST ON SUNDAY AND MONDAY
GIVING WAY TO MOSTLY DRY CONDITIONS AND HIGH TEMPERATURES IN THE MID
70S TO LOW 80S. HEADING INTO TUESDAY, A SHORTWAVE TROUGH MOVES
THROUGH THE REGION. MOISTURE TRIES TO GET PULLED NORTHWARD AS PWATS
GET INTO THE 1.25 TO 1.50" RANGE. ENOUGH 0-6KM SHEAR (45 TO 60KTS)
WILL BE IN PLACE WHERE THE FORCING IS THE BEST THAT SEVERE STORMS
COULD BE POSSIBLE, HOWEVER THIS IS HIGHLY UNCERTAIN RIGHT NOW DUE TO
DIFFERENCES AMONGST MODELS IN WHERE THE BEST FORCING WILL BE, HOW
THE COLD FRONT FROM THE NIGHT BEFORE IMPACTS WHERE STORMS INITIATE
ON TUESDAY, AND HOW MUCH RECOVERY CAN TAKE PLACE. AI AND ML GUIDANCE
ALSO HIGHLIGHT THIS DAY WITH SOME LOW PROBABILITIES FOR SEVERE
WEATHER TO OCCUR. DETAILS REGARDING THE STORM POTENTIAL WILL BE
REFINED AS WE GET CLOSER, BUT THIS IS SOMETHING TO MONITOR. AFTER
THE TROUGH EXITS THE REGION ON THURSDAY, ENSEMBLE AND DETERMINISTIC
DATA SUPPORT A SWITCH BACK TO NORTHWEST FLOW, WHICH COULD LEAD TO
SLIGHTLY COOLER TEMPERATURES FOR THE LATTER HALF OF NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1230 PM CDT FRI AUG 14 2026
LURKING AREA OF WIDESPREAD MVFR/IFR STRATUS AND RAIN POTENTIAL
EXISTS ACROSS CENTRAL IA AS OF ISSUANCE TIME AND SHOULD SPREAD
BACK NORTHWARD AND AFFECT BOTH LSE/RST WITH RST MORE LIKELY
(60%) TO SEE IFR CONDITIONS TONIGHT. RAIN AND TS POTENTIAL HAS
DECREASED SINCE LAST ISSUANCE BUT HAVE STILL INCLUDED PROB30
MVFR SHOWER MENTIONS AT BOTH TAF SITES. ASIDE FROM THE LOWER
CLOUDS AND SHRA POTENTIAL, EXPECT SOUTHEAST WINDS TO BE
PREDOMINANT ALONG WITH WIDESPREAD MID LEVEL CLOUDINESS AROUND 15
KFT.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...CECAVA
AVIATION...FERGUSON
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page