


Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
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192 FXUS63 KOAX 050428 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1128 PM CDT Fri Jul 4 2025 .KEY MESSAGES... - Spotty storms are expected to move into northeast Nebraska this evening from the west beginning around 5-7 PM. A few may become strong to severe, with damaging winds (up to 60 mph) and locally heavy rainfall through 10 PM, though additional storm chances linger overnight. - Storm chances return to southeast NE and southwest IA Saturday afternoon, with a 5-10% chance to bring quarter-sized hail and gusts to 60 mph. - Daily storm chances persist Sunday overnight through the work week. Severe weather potential remains on the lower end, though repeated rounds of rainfall could introduce flooding concerns. && .DISCUSSION... Issued at 323 PM CDT Fri Jul 4 2025 Today and Tomorrow: Water vapor imagery this afternoon depicts a peculiar mid/upper pattern across the CONUS, with a deamplifying trough over the western third of the CONUS over-top building ridging, a broad shortwave entering the Central and Northern Plains, and ridging over the eastern third of the CONUS. Drilling down to the surface locally, we find ourselves on the eastern periphery of increased cloud cover, deepening heights, and scattered showers and storms associated with a poleward-oriented surface trough draped over the Colorado/western Nebraska/Kansas area with convection. The increased surface pressure gradient has allowed those southerly winds to gust to 25-35 mph and take the edge off of the temperatures in the upper 80s to near 90 degrees, further aided by scattered to broken cloud cover. Expect temperatures to climb a few more degrees, with heat indices expected to top out around 95 degrees, making for a toasty but manageable evening outside. The main concern for the short-term forecast are shower and storm chances moving eastward ahead of the aforementioned surface troughing. While the 18z KOAX sounding depicts PWAT values of just under 1.5", a ribbon of rich moisture is expected to move eastward with those storm chance and break up the capping in place. Aided by the mid/upper shortwave, a corridor of convective development is expected to move into the forecast area by 5-7 PM, carrying with it CAPE values in the 1500-2500 J/kg range and a crumpled hodograph. Any severe chances associated with these storms will be completely dependent on storms collapsing, with gusts of up to 60 mph being possible (only a 5% chance) through 10 PM. Even those wind chances will be knee-capped to a certain extent by the increasingly moist airmass devoid of features like an "inverted v" boundary layer or strong low-level flow, with both of those increasing chances for localized areas of heavy rain. After 10 PM, rain and storm chances are expected to continue into the overnight hours, staying sub- severe and staying lower in coverage into the mid-morning hours. By 10 AM tomorrow morning, the area should be dry into the early afternoon when storm chances return on the backside of the departing frontal system. By 4 PM tomorrow afternoon convective development in northwestern Iowa more closely oriented with the main surface low is expected to begin expanding into far eastern Nebraska and southwest Iowa, bringing strong to severe storm chances back to the area through 9 PM. For this go around, the lower level sounding will feature increased DCAPE, steeper lapse rates in the mid-levels, and a similarly crumpled hodograph all pointing to increased damaging wind chances and hail up to 1" in diameter. Once those storms exit the area, we`ll enjoy a dry night with lows dipping into the 60s and northwesterly winds. Sunday and Beyond: Sunday will start the upcoming week with a dry forecast as the earlier system exits the area before the active pattern for the upcoming week settles in. A cutoff low is expected to dip southward from the main mid/upper flow and spin off the California Coast, amplifying a narrow ridge with northwesterly/diffluent flow dumping out into the mid-Mississippi Valley for much of the week. Ensembles are keen on allowing the warmer west and mid/upper ridge associated with it to keep temperatures warm (upper 80s to low 90s) despite us being only on the eastern periphery of it, and moving nearly daily rain and storm chances in the form of shortwaves and High Plains convection into the area. Details as to the timing and intensity of the convection will continue to be hard to predict until we get closer, and we could be heading into another poorly performing CAM week, similar to the last. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1128 PM CDT Fri Jul 4 2025 The southern portion of the line of storms has fizzled away leaving behind a broken line of showers that may move into KLNK around 06Z. Otherwise, storm chances wane until the next round arrives around 08-09Z where we may see storms redevelop along the original boundary right over KOMA as well as a second line move into northeast Nebraska. We`ll see these storms move through, exiting the area around 12Z with winds turning more southwesterly. Once storms exit, attention turns to low stratus expected to develop over northwest Iowa and expand southward into KOMA. Some models bring this west as well, into KLNK and KOFK, but highest confidence is in it impacting KOMA around 13-16Z Saturday morning. This should erode by 16Z with clearing skies for the afternoon. We have additional low chances for storms Saturday afternoon (15-30%), but chance is too low to include in the TAFs for now. More likely sites stay clear. Winds will shift to west then northwesterly by Saturday afternoon, staying out of the northwest through the remainder of the TAF period. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Petersen AVIATION...McCoy