textproduct: La Crosse

KEY MESSAGES

- Near to slightly above normal highs in the low to mid 80s near 90 for Tuesday. Potential for below normal temperatures for latter half of the week into the weekend.

- Widespread precipitation chances Tuesday night through Thursday. Overall confidence for severe storms is low, dependent on diurnal timing of local frontal passage Wednesday.

DISCUSSION

Issued at 1255 PM CDT Sun Jul 5 2026

Today:

Aggravated cumulus can be seen burbling on satellite imagery early this afternoon as daytime heating permits parcels to reach their convective temperatures. A thick low level calm wind profile limits duration or extent of precipitation or storms, seen on RADAR imagery popping up for 1 or 2 scans before cooler rain-cooled air overcomes any attempts at additional rising updrafts.

Through Tuesday:

A relatively stagnant upper level pattern keeps a mostly persistent forecast through the Upper Mississippi River Valley for the start of the week with daytime highs in the low to mid 80s and low afternoon precipitation potential primarily along our western periphery. The responsible mid-upper level low seen on early afternoon satellite water vapor imagery loops progressing from Iowa into Missouri expected to sit over the southern Great Lakes causing east wind over the Great Lakes. Return flow amplifies from the Central through Northern Plains, eventually advecting east through the Upper Mississippi River Valley Tuesday night through Wednesday.

Midweek Precipitation Potential:

Accompanying precipitation potential increases heavy rain threat as the persistent upstream return flow allows PWATs to push 1.5" to 2" according to highest (70-100%) LREF probabilities. Diurnal timing of the passing wave will determine local storm and severe chances as LREF intermember and intramember variation exhibits lowest SB/MU CAPE up to 1000 J/kg with overnight passage and highest instability of 2500 J/kg+. While overall confidence for storms and severe weather remains low, Wednesday shows locally highest potential for unstable airmass over the forecast area which causes more uncertainty due to sky cover limiting diurnal heating influence as precipitation potential increases initially Tuesday night. Regardless, limited available shear limits storm strength, hinging on frontal passage primarily in the lowest levels due to the inherent wind shift.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 643 PM CDT Sun Jul 5 2026

Isolated showers and a few rumbles of thunder will be possible through the early evening before dry conditions are then expected through the rest of the TAF period. Light and predominantly southeast winds will remain through the forecast period. VFR conditions are expected, however the exception is the potential development of valley fog over many of the valleys in the area. With the surface being relatively moist still and the light winds, fog may form across the valleys tonight.

ARX WATCHES/WARNINGS/ADVISORIES

WI...None. MN...None. IA...None.