Area Forecast Discussion

KEY MESSAGES

- Warmer temperatures today through Thursday with highs well into the 70s for most. Temperatures will cool back down on Friday and into the weekend with highs generally in the upper 50s to 60s.

- Showers and storms likely (70-90% chance) for Thursday evening and overnight. A few strong to severe storms cannot be ruled out.

DISCUSSION

Issued at 1153 PM CDT Mon Apr 20 2026

Today - Wednesday: Drier and Much Warmer

Upper-level ridging will be the name of the game over the next couple of days allowing for fairly robust warm air advection to move into the region bringing much warmer temperatures. As a result, the NBM inter-quartile range for high temperatures ranges from the lower 70s to lower 80s from today through Thursday. A quick moving shortwave trough does push through the local area during the morning and into the early afternoon, however likely would not see much precipitation potential with this as the stronger forcing would remain southeast of the area as peak heating arrives. As a result, not seeing much precipitation chances in the most recent HREF with the bulk the higher probabilities well to our south in the IL/IN region. Otherwise, subsidence under this aforementioned ridge should keep precipitation potential at a minimum through Wednesday.

Thursday: Showers and Storms Likely

The pattern changes slightly into Thursday as a upper-level trough pivots into the Northern Plains and closes off with a rapidly developing surface low along with it. As this surface low deepens and pulls northward, a trailing cold front pushes east towards the local area during the evening and overnight hours on Thursday. Definitely would have the forcing along the front for precipitation, main question would really be any severe potential. Currently, the NAM/GFS generally agree on keeping the stronger upper-level jet streak further west of the local area, as a result shear aloft is generally fairly absent as noted with only 20-30 kts of 0-6km shear in the NAM/GFS that would be parallel to the front, suggesting a linear mode. As a result, with respectable probabilities (40-70%) for MUCAPE over 1000 J/kg in the EC ensemble west of the Mississippi River, would expect storms to form along the cold front, but individual updrafts would likely not maintain very well. Shear profiles generally seem to be favored in the low-levels which draws into another question how much those could be utilized with a decent EML present in the GFS/NAM resulting in some capping across the local area. If no cap is present, then would think a wind and weak spin-up risk would be a possibility. However, confidence in how any severe potential would manifest is fairly low at this point as marginal mid-level lapse rates (6.5-7.5 C/km) and relatively unimpressive MUCAPE values would suggest not an overly impressive hail threat assuming a capped atmosphere. Regardless, AI/ML guidance does paint some higher severe outlook probabilities for the local area west of the Mississippi River so certainly Thursday evening and overnight remains a period to monitor. That being said, still a lot of questions on how the convective environment will manifest though.

Friday & This Weekend: Cooling Trend

In the wake of the aforementioned cold front, a cooler airmass pushes into the local area for Friday and into the weekend with the inter-quartile range for high temperatures in the NBM ranging from middle 50s to middle 60s for the weekend. However, guidance generally agrees on keeping the aforementioned upper-level closed low in south-central Canada for the weekend, as this slow pulls northward it pushes another shortwave trough into the region for early next week which increases our precipitation chances, however vast uncertainty still remains on the timing and exact location of this trough as it pushes through the region.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1210 AM CDT Tue Apr 21 2026

VFR conditions expected for the next 24 hours at the terminals. LLWS will be possible at both KLSE and KRST through the overnight hours given the generally weak low level winds. Southerly surface winds will continue to decrease over the coming hours before shifting to the north behind a weak cold front that moves through the area after 12Z. Winds are expected to become light and variable after 00Z tomorrow evening.

HYDROLOGY

Issued at 1153 PM CDT Mon Apr 20 2026

Flooding persists along the Wisconsin and Yellow River with minor flooding ongoing at both Necedah, WI and Muscoda, WI. Current expectation is for the river stage at both locations to fall over the next few days as no precipitation is expected to fall in these basins through at least Wednesday. The river stage at Muscoda, WI will likely fall below flood stage late this morning or this afternoon with Necedah, WI likely not falling below flood stage until Wednesday afternoon.

ARX WATCHES / WARNINGS / ADVISORIES

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