textproduct: Omaha/Valley

KEY MESSAGES

- Widespread rainfall of 2 to 4 inches expected through Thursday, with locally higher amounts. A Flood Watch has been issued for Tuesday evening through Thursday. - If we get any clearing on Wednesday, a few strong to severe thunderstorms will be possible during the afternoon and evening, mainly in southeast Nebraska. - Rain will end Thursday night, with cooler, dry conditions expected through the weekend.

DISCUSSION

Issued at 1051 PM CDT Mon Sep 28 2026

High clouds have spread across the area while lower clouds from earlier have cleared. Winds are out of the southeast. Looking at satellite we have a couple of main features that will aid in the heavy rain forecast for the next couple of days. We see an upper-level trough over the Great Basin and Sierra Nevadas, and Hurricane Polo along the southern coast of Baja California. Hurricane Polo will inject additional tropical moisture into the warm conveyor belt ahead of the upper-level trough leading to a significant amount of moisture advection into west Texas, New Mexico, Colorado, Kansas, and Nebraska over the next couple of days.

The first round of rain arrives tomorrow morning as the western trough pushes eastward, shifting the warm conveyor belt into eastern Nebraska. Expect a complex of showers with a few embedded storms to push through south-central into northeast Nebraska, perhaps all the way down to I-80. This will clear by mid-morning but with strong isentropic upglide across the region through the day, I'd expect to continue to see areas of light rain continuing into the afternoon. The next round of heavier rain will arrive tomorrow evening, this time more across southeast Nebraska into southwest Iowa. A swath of 1-2 inches of rain is expected with this round, looking more likely around Beatrice to just north of Nebraska City.

Additional shortwaves will continue to bring periods of heavier rainfall into Wednesday with heaviest rainfall expected overnight Tuesday night and again Wednesday night. We're watching Wednesday night for some potential for severe storms. Wednesday night we see the remnant surface low from Hurricane Polo lift north across central Kansas into southeast Nebraska. This will steepen lapse rates, increasing environmental instability. We'll also see fairly good low-level shear along the warm front lifting north. Right now the greatest severe potential is to our south with the surface warm front not quite making it into southeast Nebraska, but if it does push farther north, we could see potential for wind and tornadoes shift north into our area.

Wednesday evening may be the time we see heaviest rainfall northeast of the surface low. At this time we see strong moisture advection overtop of the surface frontal boundary. PWAT values around 2.1 to 2.2 inches is well in excess of our climatological max of 1.72 inches for October 1st, or even most of the month of September. Every deterministic model I bring up shows 2.1 to 2.2 inches across much of eastern Nebraska into western Iowa. This will create highly efficient rainfall with ensemble guidance highlighting potential for a broad area of 1-2 inches of rain over a 6-hr period. This on top of already saturated ground really increases the potential for river flooding Wednesday night going into Thursday with lingering river impacts potentially into Friday-Saturday on main-stem rivers such as the Platte and Missouri (south of the Platte).

Rainfall clears off to the southeast Thursday as the upper-level trough shears away with the cold front sinking south of our area. Skies may clear Thursday night into early Friday potentially leading to some significant widespread fog Friday morning. Going into the weekend, we're going to see a period of quiet weather with a decaying ridge building over the region. We'll be glanced by the southern edge of a Canadian High keeping temperatures on the cooler side Friday and Saturday. Saturday night a dry cold front looks to move through bringing a reinforcing surge of cooler air for early next week keeping highs in the low-to-mid 60s and lows in the upper 40s to low 50s.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1229 AM CDT Tue Sep 29 2026

Broken to scattered clouds at 25,000 feet are observed over most terminals this morning leading to VFR conditions. Will see a band of rain showers overspread terminals within the next few hours with ceilings largely staying VFR, and there could be a few storms embedded (15-20% chance) but confidence on any terminal seeing -TSRA remains too low for mentions. KOFK could see some gustiness of 20-25 kts after 12z too. By the late morning hours, will see a break in rain showers before a second round approaches terminals in the afternoon leading to MVFR ceilings and visibility reductions which last through the end of the TAF cycle. Southeast winds become southerly by the afternoon at 12 kts or less.

OAX WATCHES/WARNINGS/ADVISORIES

NE...Flood Watch from this evening through Thursday evening for NEZ015-018-030>034-042>045-050>053-065>068-078-088>093. IA...Flood Watch from this evening through Thursday evening for IAZ043-055-056-069-079-080-090-091.