textproduct: La Crosse

KEY MESSAGES

- Winter storm exiting east this morning. Bulk of additional snow likely done by daybreak (up to 1"). Strong/gusty winds persist this morning, strongest west of the Mississippi River (30 to 40 mph). Flurries, scattered snow showers possible thru the afternoon.

- Next impact snow maker Thu afternoon/night with a few inches of snow possible. Southeast MN/northeast IA harbor the higher chances/potential amounts.

- Very cold weekend with single digit highs Sat/Sun and teens below zero Sun morning. Wind chills as cold as -25 to -30 F Sun morning.

DISCUSSION

Issued at 300 AM CST Wed Dec 10 2025

> TODAY: winter storm exits east early but scattered snow showers, flurries likely to linger for some locations. Strong morning winds, decreasing for the afternoon.

Last burst of snow driving southeast across the region on the backside of departing winter storm. Timing moves this away from the local area near 12z with upwards of 1" additional for some.

The area isn't done with snow though as favorable low level lapse rates, cold air advection/weak instability suggest flurries and/or scattered snow showers will remain possible through the afternoon. Not expecting much/if any additional accumulations.

Winds stay strong/blustery this morning, but pressure gradient starts to relax as the storm's sfc low moves further east, and winds will start to slacken moving through the afternoon into evening.

> THU/FRI: next snow maker Thu afternoon/night with a few inches trending across southeast MN/northeast IA.

Next shortwave in this parade of perturbations drives southeast from western Canada, across the northern plains and then over IA Thu. An elongated, narrow band of Fgen with this feature, promising a somewhat narrow band of precipitation. LREF paints 30-40% chances for 3+" but at 10:1 snow ratios. With current forecast favoring ratios more 15:1, 30-40% chances would be more in line with the threat for 4.5+". Some disagreements in how the system tracks across the region between the ensemble members - but show some consensus with southeast MN/northeast IA harboring the higher snow chances/amounts locally. A winter weather advisory will likely be needed if the current scenario bears out.

Another ripple in the flow is progged to move across northern portions of the region on Friday. A weaker feature without much QPF attached to it. Snow chances mostly north of I-94 with minor accumulations possible (a few tenths).

> WEEKEND: very cold with single digit highs and teens below normal for Sun morning. Snow chances mainly northeast IA Sat.

Ripples in the upper level flow will continue to carve out a deeper long wave trough moving into the weekend, allowing for a much colder slug of air to work across the upper mississippi river valley. 850 mb temps progged to drop from -9 C at 12z Thu to -19 C by 12z Sat. 850 mb temp anomalies in the NAEFS and EPS around -1.5. EFIs for MaxT and MinT are as much as 0.9 to 0.95 with a non zero SoT. About 50% of the EPS and GFS suggest highs won't climb above freezing Sat for a chunk of the forecast area. Sun morning lows in the teens below zero (70 to 90% chances in the GrandEnsemble) - and with even just light winds, wind chills from 25 to 30 below could be realized. Potential cold weather adv in this period. Sunday daytime isn't much better with single digit highs still trending. Warmer - more seasonable air looking to return as we move into the new work week (more on that in the section below).

The next shortwave trough is set to drive southeast across the northern plains and then over IA during the day Sat. Some differences in the track of the system between and within the EPS and GEFS suites, with a few more of the EPS favoring a more northward track. Higher chances for snow via the EPS mean as a result, although speed of the system holds potential amounts in check. The GrandEnsemble paints roughly 20-40% chances for 1" or greater across northeast IA at this time.

> START OF NEXT WEEK: upper level pattern change, return to normal temps

The upper level ridge the long term guidance has continued to flaunt just to our west may finally push east off the west coast, with WPC clusters all in good agreement on moving the ridge axis over the region for the start of the new work week. Solid, increasing signal for this to occur - and confidence is increasing in the likelihood. After a very cold weekend, a return to at least more "normal" for mid December temps would result.

EPS and GEFS kick the ridge fairly quickly east, but hold zonal, progressive flow a loft. Fluctuations in temps between shortwave ridging/troughing...but no signficiant cold blast in this scenario.

There would be pcpn chances here and there, but timing differences between the ensemble members lowers predictability at this time.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1126 AM CST Wed Dec 10 2025

Band of snow sagging southeast through central Minnesota at 10.18Z TAF issuance creates immediate term aviation impact concerns with TEMPO IFR visibilities within the heaviest snowfall of the transient band.

A short reprieve in MVFR-IFR ceilings possible through Thursday morning before subsequent snowfall chances progress southeast, primarily affecting airports west of the Mississippi River locally in southeast Minnesota and northeast Iowa. Therefore, KRST TAF site will likely be impacted Thursday afternoon/evening.

ARX WATCHES/WARNINGS/ADVISORIES

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