textproduct: Omaha/Valley

KEY MESSAGES

- Widespread showers and storms expected late tonight into Friday morning (60-90% chance). A few storms may be strong to severe with hail the main threat (5% chance).

- Showers and storms expected again for Friday afternoon/evening (60-80% chance). Some storms may be strong to severe (15-30% chance), mainly east southeast of a line from near Red Cloud to Fremont to Onawa.

- Lingering precipitation late Friday night may lead to a dusting of snow (40-60% chance) in far northeast Nebraska.

DISCUSSION

Issued at 134 PM CST Thu Mar 5 2026

Today and tonight:

Fog from this morning has lifted to stratus as it tries to clear out this afternoon. Temperatures are forecast to warm into the upper 50s to low 60s this afternoon.

A complex forecast is in store through the next 36 hours with elevated storms expected to develop this evening into the overnight hours and a second round of storms expected on Friday ahead of an advancing cold front. Both rounds of storms have potential for severe weather.

This evening we see a mid-level trough deepening on the lee-side of the Rockies over eastern Colorado into western Kansas. This leads to an increase in southerly flow off the surface bringing warm air north of the surface warm front. This will lead to a strong surface inversion with low stratus expanding northward through the evening hours. As warm air advances aloft we see steepening lapse rates above around 8000ft generating initially a modest amount of elevated instability as the first upper-level shortwave triggers a few storms starting around 7-9pm. As this line of storms moves east, we'll continue to see steepening lapse rates and increasing instability across our southern counties, with a few storms potentially becoming strong to severe across southeast Nebraska and southwest Iowa toward midnight.

After midnight we'll see more widespread destabilization above the boundary layer as the mid-level trough and deepening surface low shift eastward. This leads to the amplification of southerly flow into eastern Nebraska and western Iowa with the advancement of the upper-level warm front northward toward the Platte River. We see a second wave of storm development along this west-east boundary between 2-4am, in a much more unstable elevated environment (1500-2000 J/kg MUCAPE). While lapse rates will be steep, wind shear through the unstable layer is relatively modest as winds are mostly unidirectional with even some backing in the wind profile. This leads to more of a large hail and heavy rain threat with these storms. Damaging winds may be hard to get as they would have to be strong enough to penetrate the strong surface inversion in place, but can't be completely ruled out. These stronger storms will track northeast, staying north of the advancing surface warm front. We'll see rapidly diminishing elevated instability after daybreak leading to storms trending weaker and mostly clearing the area by 9am.

Friday:

Once these storms clear, attention turns to the next round of storms Friday afternoon. With the surface warm front now oriented across northeast Nebraska into north-central Iowa we see the southern 2/3rds of our area situated in the warm sector of the approaching surface low. Models still aren't in great agreement on the speed at which the surface low will move in, leading to differences in how long and how much of our area remains in the warm sector as storms are forecast to develop Friday afternoon/evening. While the CAMs are a little faster with the speed of this system, the GFS brings it in more slowly leading to a greater portion of our area in the warm sector through the afternoon as storms initiate. In either case, we expect initially discrete storms to develop around 2-4pm over southeast Nebraska into southwest Iowa with a line of storms blowing up along the cold front just west of the discrete cells. These discrete storms will need to be monitored closely as though wind profiles don't show much directional shear, there will be enough speed shear for a few rotating supercells ahead of the cold front.

Looking back at our two scenarios, a faster-moving surface low will mean a faster-moving cold front which will only shorten our window for seeing these potential supercells. This will limit the potential for severe weather mainly to far southeast Nebraska and southwest Iowa, near the Missouri state line. A slower-moving surface low and cold front will keep the warm sector over more of our area through the afternoon, with storms developing over a greater portion of our area ahead of the cold front. This could bring the tornado and large hail threat farther north, but still more likely confined to areas southeast of I-80. Storms that develop along the cold front could still produce large hail and damaging winds, but the larger hail and tornado threat will be confined to the discrete storms ahead of the front.

The cold front should clear east of our area by 6-7pm. CAMs show a second line of storms moving in as the upper-level trough axis moves through around, but by then the environmental instability and shear will be much weaker leading to more garden-variety storms, possibly even just rainfall with no lightning between 7pm-12am.

Colder air will be moving into northeast Nebraska behind the cold front with temperatures dropping below freezing after sunset Friday evening. Meanwhile, wrap-around precip on the northwest side of the surface low will be tracking northeast out of central Nebraska, bringing a chance for some light snow over northeast Nebraska. Moisture will be limited which will lead to only modest accumulations generally less than an inch between 8pm-12am. Any lingering precip should clear off to the northeast by 12am.

Saturday and beyond:

Cooler temperatures Saturday morning as post-frontal north winds drop temperatures into the mid 20s to low 30s across eastern Nebraska and western Iowa. We see a mid-level ridge push through as the upper-level trough shears away, leading to a return to milder westerly flow Saturday afternoon. This will allow temperatures to warm back into the low 50s with clearing skies. Sunday, an advancing upper-level wave over Minnesota will ramp back up southwesterly flow across our region warming temperatures back into the 60s to low 70s Sunday afternoon. Warm temperatures continue through Monday and Tuesday with highs in the upper 60s to mid 70s. Our next chance for precipitation looks to be Tuesday/early Wednesday as we see a cut-off low get picked back up into the general flow pattern and pass just to our south. We mostly get clipped by the northern edge of this system with best chances for precipitation generally across southeast Nebraska and southwest Iowa. Beyond that we may see a day or two with highs back down in the 50s before temperatures ramp back up toward upper 60s-70s late in the week.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1130 AM CST Thu Mar 5 2026

TAFs are a bit lengthy due to a complex scenario expected overnight tonight into Friday morning. Clearing skies this morning with increasing high clouds expected through this afternoon. Winds remain out of the southeast. As we go into this evening we'll see low clouds spread northward, initially MVFR lowering to IFR. Above the low-cloud layer, we'll see thunderstorm development starting around 03-04Z with bases around 8,000-10,000 ft. These storms will likely not be enough to mix out the low clouds, leaving at least BKN IFR cigs and potentially 1-2SM vis while thunderstorms impact the terminals overnight.

The first round of scattered showers and storms will be moving along a line from west to east from 04-07Z. A second round develops along a boundary oriented west to east closer to 08-10Z, mainly impacting KOFK and KOMA through around 14Z. All this continues to be above IFR/LIFR cigs locked in place across the region. While thunderstorms clear by around 14Z, low cigs remain, with cigs starting to gradually improve around 16-17Z.

OAX WATCHES/WARNINGS/ADVISORIES

NE...None. IA...None.