FXUS63 KOAX 041718 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1218 PM CDT Tue Aug 4 2026 .KEY MESSAGES... - Cold front moving in overnight brings scattered showers with a few rumbles of thunder to northeast Nebraska Tuesday morning (40-70% chance). - Rain chances shift to southeast Nebraska and southwest Iowa Tuesday evening into Wednesday (60-90% chance). - Milder temperatures through Thursday, warming back up going into the weekend. Dry, seasonably warm weather expected over the weekend. && .DISCUSSION... Issued at 1118 PM CDT Mon Aug 3 2026 A few showers are starting to move into northeast Nebraska along the cold front as it pushes into Knox County. As this front moves through we'll see winds shift to northerly and scattered showers spread across the area. While model soundings show decent shear (35-50kt) behind the front, instability will be limited making it difficult for us to see much more than a few lightning strikes with our strongest storms overnight. Looking back at the larger picture we have a cold front moving through, stemming from a longwave trough located over central Canada. This cold front has brought a cooler Canadian air mass south into the Northern Plains. The cold front looks to stall across our area tomorrow. Showers and storms trigger along this boundary as weak shortwaves move across our area. Showers will likely remain fairly scattered through the morning into the afternoon due to weak forcing. PWAT values north of our 90th percentile may allow for some locally heavy rainfall from these showers and storms, but they should move well enough to not be much of a threat for flash flooding. A more substantial shortwave moves through tomorrow night into Wednesday bringing greater coverage of showers and storms. Again, we'll lack enough instability for much of a severe weather threat overnight, but ample moisture as well as potential for training storms along the frontal boundary could lead to greater potential for flash flooding into Wednesday morning. We'll get a better idea of the exact corridor for heavier rainfall once the front stalls this afternoon, but it should land fairly close to our forecast right now for areas along and just south of the I-80 corridor. Highest rainfall amounts through Wednesday look to be mostly over our southwest Iowa counties which could see around 1-2 inches of rain. Areas along the heavier rain axis in Nebraska will more likely see anywhere from 0.5-1.25 inches. Locally higher amounts will be possible, especially if we see any training storms. Showers and storms will taper off through the afternoon, ending by around 7pm Wednesday evening. With cloud cover and rain through much of the day, highs on Wednesday look to only reach into the 70s. Even areas in northeast Nebraska that likely won't see much rain at all will see highs stay in the mid-to- upper 70s due to the Canadian air mass in place. Thursday we see one more vort max round the base of the upper- level trough across our area before it slides off to the east. This could bring a few light showers Thursday evening, but our air mass should be too dry for much to reach the ground at that point. Temperatures will stay fairly mild with mostly clear skies, only reaching into the low 80s Thursday afternoon. Going into the weekend, the ridge over the Desert Southwest expands eastward, filling in behind the departing trough. This will allow temperatures to warm back up with highs in the upper 80s on Friday and low-to-mid 90s on Saturday. Not expecting any rain through the weekend, but will start watching for rain chances returning possibly as early as Sunday night into early Monday, but more likely Monday night into Tuesday. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...Issued at 1220 PM CDT Tue Aug 4 2026 Line of showers and storms in the northern half of the area are expected to push southeast and out of the area by 6pm tonight. These showers and storms will be impacting LNK and KOMA from about 00Z to 02Z this evening. More convection is expected to develop by 9pm tonight, and expand and slide east through the overnight hours. These storms should remain sub-severe, but will produce some wind gusts of 40 mph or so and leave MVFR cigs at KOMA and perhaps KOFK and KLNK, too. Wildfire smoke drifting in from the north is mostly elevated at 5-8,000 feet, but there will be some at the sfc, too... especially on the northern and western edges of the area as the TAF period continues. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...McCoy AVIATION...Nicolaisen