textproduct: Omaha/Valley

KEY MESSAGES

- Strong to severe thunderstorm chances continue in eastern Nebraska and western Iowa this afternoon and early evening. Large hail will be the primary concern, though damaging wind gusts and brief tornado remain possible.

- Warm, dry and windy conditions will brining elevated fire weather concerns on Thursday, particularly in east-central Nebraska.

- Additional severe thunderstorm chances are expected on Friday. Cooler air arrives Friday night into the weekend. Saturday and Sunday morning lows will dip below freezing for some locations, with highs only peaking in the 50s on Saturday.

DISCUSSION

Issued at 1042 AM CDT Wed Apr 15 2026

Today and Tomorrow...

An upper-level wave ejecting northward into the central Plains is pushing an attendant surface low, currently positioned in southeast Nebraska, northeastward into central Iowa through the day. This feature will draw a warm sector northward in eastern Nebraska and southwest Iowa this afternoon with a weak convergent boundary draped generally along to just north of the I-80 corridor. Afternoon highs temperatures are expected to peak in the 70s. Instability will increase through the day, with a narrow ribbon of SBCAPE values exceeding 2500 J/kg wrapping into the mid-MO Valley. A few elevated supercells have already track across northeast Nebraska late this morning, producing severe hail. The main questions will be if the warm sector pushes eastward outside of the forecast area before surface base convection occurs. The latest CAM guidance varies with some members initiating storms near the Missouri River longitude, while others don't develop storms until the feature is further into western Iowa during the later afternoon hours. If surface based storms are able to initiate in the forecast area, an initial supercell storm mode is possible with large hail the primary hazard given mid-level lapse rates approaching 8-8.5 deg/km. An isolated tornado threat will also be possible with any surface based storm able to establish itself given sufficient low-level hodograph curvature and backing surface winds, especially near the aforementioned convergent boundary. Damaging wind gusts and locally heavy rainfall will also be on the table. Additional chances for elevated supercells, with hail the primary hazard, will continue north of the low through the afternoon.

A brief period of mid-level ridging will slide across the area on Thursday, bringing a short break from the severe weather potential along with the return of fire weather concerns. Afternoon highs temperatures are expected to peak in the 80s, approximately 15-20 degrees above climatological norms. Afternoon relative humidity values are expected to drop into the 15-35% range, with the lowest values expected towards east-central Nebraska. Gusty south- southwesterly winds of 20-30 mph tomorrow afternoon will help to elevate fire weather concerns, though confidence in winds reaching Red Flag Warning criteria is low. Most EPS/EPS-AIFS members keep winds capped around 30 mph. Additionally, RAP model soundings top out winds at the top of the mixed layer at 20-25 kts. Therefore, we are continuing the Fire Weather Watch for Thursday afternoon and evening.

Friday and Beyond...

Severe weather potential returns on Friday as an upper-level trough pushes into the central and northern Plains. An associated surface low is expected to push across Nebraska through the day, with an attendant cold front pushing eastward across the region. High temperatures will depend on where the cold front is before peak daytime heating, with values peaking in the 70s to low 80s ahead of the front and the 60s behind the front. Gusty northwesterly winds of 30-35 mph will move in behind the front.

Convective initiation is expected along the cold front with strong forcing for ascent and ample instability ahead of the boundary. Yet again, the main question will be how quickly the front crashes through the area. SPC currently has far southeast Nebraska clipped in an Enhanced Risk (level 3 out of 5) with a Slight Risk (level 2 out of 5) draped further west. An initial supercell storm mode capable of all severe weather hazards looks probable for any storms that develop in the warm sector. We will have to see how things trend in regards to cold front placement into the afternoon as the system approaches. Any lingering precipitation will work its way out into Saturday morning, with a chance (10-20%) for a brief rain/snow mix on the back side of the departing precipitation shield.

The post-frontal airmass will certainly be felt on Saturday, with morning lows temperatures dipping in the 30s, followed by afternoon highs topping out in the 50s. Lows again Sunday morning will drop near freezing for most locations, with the upper 20s expected across northeast Nebraska. Ensure any sensitive vegetation is protected and hoses are disconnected. Temperatures will gradually rebound later Sunday into early next week as mid-level ridging pivots into the central Plains. Highs on Sunday are expected in the 60s, rising to the 70s Monday and Tuesday.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1119 AM CDT Wed Apr 15 2026

A band of MVFR ceilings continues at KOMA and KLNK late this morning and are expected to scatter out and return to VFR conditions by 15/19-20Z. Otherwise, scattered showers are expected to expand across eastern Nebraska into the afternoon, with the highest confidence in impacts at KOFK and KOMA. There is a chance (15%) for a strong thunderstorm in eastern Nebraska this afternoon, bringing gusty winds and brief, isolated IFR conditions. However, confidence is too low in these storms impacting the TAF sites to include at this time. Model guidance continues to show storm development north and east of KOMA. Amendments will be made if needed.

Otherwise, skies will gradually break up and clear from west to east through the evening and overnight period. Winds will generally remain calm, unless influenced by passing storms, residing out of the north-northwest and eventually shifting to southerly late tonight.

OAX WATCHES/WARNINGS/ADVISORIES

NE...Fire Weather Watch from Thursday afternoon through Thursday evening for NEZ011-012-015>018-030>033-042-043. IA...None.