615
FXUS63 KARX 071748
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1248 PM CDT SUN SEP 7 2025
KEY MESSAGES
- WARMER WEEK AHEAD! HIGHS RETURN TO THE 70S FOR MOST, PUSHING
TO AROUND 80 FOR THE END OF THE WEEK.
- THE RISK FOR RAIN SHOWERS FOR LATE MONDAY THROUGH WEDNESDAY
HAS SHIFTED NORTHWESTWARD, BUT SOUTHEAST MINNESOTA INTO
CENTRAL WI COULD STILL SEE PERIODIC SHOWERS.
DISCUSSION
ISSUED AT 1248 PM CDT SUN SEP 7 2025
TEMPERATURE TRENDS FOR THE UPCOMING WEEK
SURFACE HIGH PRESSURE IS TRANSITING THE REGION THIS AFTERNOON
AND DEPARTS THIS EVENING. LOW TO MID-LEVEL WARM AIR ADVECTION IS
ALREADY UNDERWAY AND CONTINUES FOR THE NEXT 24-36 HOURS.
HOWEVER, LOW TEMPERATURES TONIGHT OVER WESTERN AND CENTRAL
WISCONSIN COULD STILL FALL INTO THE MID TO UPPER 30S DEPENDING
ON THE DEGREE OF DECOUPLING THAT TAKES PLACE. HAVE PUSHED LOWS
DOWN TO THE NBM 5-10TH PERCENTILE IN THE SAND BOGS AND CENTRAL
WISCONSIN TO ACCOUNT FOR THIS POSSIBILITY. THESE TEMPERATURES
WOULD BE SUPPORTIVE OF PATCHY FROST IN FAVORED LOCALES.
HIGH TEMPERATURES ON MONDAY BOUNCE UPWARDS BY 10 DEGREES
COMPARED TO THIS AFTERNOON, HITTING THE LOW TO MID 70S, THEN
SLOWLY INCH UPWARDS INTO THE MID TO UPPER 70S BY MIDWEEK. THERE
ISN'T ANY SIGNIFICANT AIRMASS CHANGES ON THE DOCKET FOR THE
REMAINDER OF THE WEEK WITH HIGHS REMAINING IN THE UPPER 70S TO
LOW 80S.
PERIODIC LIGHT RAIN SHOWERS TO START THE WEEK
INCREASING 850-750-MB THETA-E ADVECTION LATE TONIGHT COULD BE
ENOUGH TO SPARK A FEW ELEVATED SHOWERS WEST OF THE MISSISSIPPI
RIVER AS HINTED AT BY A NUMBER OF 12Z CAMS. THESE SHOWERS WILL
BE BATTLING LOWER TROPOSPHERIC DRY AIR, SO HAVE ADDED SPRINKLE
WORDING TO THE GRIDS TO ACCOUNT FOR THIS POTENTIAL.
A SURFACE BAROCLINIC ZONE DEVELOPS ACROSS THE HIGH PLAINS TO
START THE WORK WEEK, BUT FAILS TO ADVANCE EASTWARD THROUGH THE
WEEK WITH UPPER LEVEL RIDGING AMPLIFYING OVERHEAD. RECENT TRENDS
FROM THE LREF ENSEMBLE SUITE ARE PULLING THE HIGHER PRECIPITATION
PROBABILITIES FOR MONDAY NIGHT INTO EARLY WEDNESDAY--WHICH WERE
OVER THE REGION YESTERDAY--BACK TO THE NORTHWEST AND CLOSER TO
THE HIGHER THETA-E CORRIDOR. WHILE THE FORECAST IS CERTAINLY NOT
DRY, YET, AREAS TO THE NORTH AND WEST OF A WATERLOO, IA TO
WISCONSIN RAPIDS, WI LINE HAVE A BETTER CHANCE (40-50%) OF
SEEING LIGHT SHOWERS COMPARED TO THOSE FURTHER SOUTH.
MOVING TOWARDS THE MIDDLE TO END OF THE WEEK, THE STRENGTHENING
UPPER RIDGE AND RESULTING SUBSIDENCE WILL LIMIT THE RISK FOR
SHOWERS AND THE NBM HAS COME IN PREDOMINANTLY DRY.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1145 AM CDT SUN SEP 7 2025
CIGS: A FEW FAIR WEATHER CU THIS AFTERNOON FOLLOWED BY SKC
CONDITIONS THIS EVENING THROUGH MOST OF THE OVERNIGHT. LOW/MID LEVEL
WARM AIR ADVECTION FAVORS THE DEVELOPMENT OF A MID LEVEL VFR DECK OF
CLOUDS ACROSS IA OVERNIGHT, SHIFTING NORTHEAST ACROSS THE TAF SITES
AFTER 12Z. A FEW HOURS OF 4-5KFT CIGS LIKELY MON MORNING.
CAVEAT FOR KLSE - WHILE FOG IMPACTS OVERNIGHT ARE NOT ANTICIPATED
(SEE SECTION BELOW), A LAYER OF STRATUS COULD DEVELOP ACROSS THE
MISSISSIPPI RIVER WITH DECOUPLED WINDS POTENTIALLY BRINGING THOSE
ACROSS THE AIRPORT. A LOW PROBABILITY AT THIS TIME (<20%), BUT
SOMETHING TO MONITOR.
WX/VSBY: INITIAL LIGHT WIND FIELD IN THE VERTICAL WILL SEE INCREASES
IN SPEED AND LOWERING OVERNIGHT AT KLSE PER RAP/HRRR SOUNDINGS.
THIS, ALONG WITH A RELATIVELY LARGER SPREAD IN T/TD, WILL WORK
AGAINST FOG IMPACTS AT KLSE.
MID LEVEL CLOUDS MON MORNING MIGHT PRODUCE A SPRINKLE OR TWO, BUT
LOW PROBABILITIES (<15%) PRECLUDE INCLUDING MENTION IN THE FORECAST.
WINDS: NORTHWEST BECOME LIGHT SOUTH/SOUTHEAST TONIGHT. WILL PICK UP
FROM THE SOUTH MONDAY WITH AFTERNOON GUSTS IN THE LOW 20 KTS.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...SKOW
AVIATION...RIECK
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