922 FXUS63 KOAX 312012 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 312 PM CDT Thu Oct 31 2024 .KEY MESSAGES... - Crisp and cool this evening with light winds. - Saturday through Monday night will feature several rounds of showers and storms, including some potential for strong storms on Sunday and Monday. && .DISCUSSION... Issued at 312 PM CDT Thu Oct 31 2024 ...Tonight and Friday... A surface ridge of high pressure will continue to build through the mid MO Valley this afternoon and evening with west-northwest winds becoming light and variable before switching to south or southeast overnight. Temperatures will drop into 40s at most locations by sunset or shortly thereafter, leading to crisp conditions for those out and about. Overnight lows are expected to dip into the low/mid 30s. A midlevel disturbance is forecast to track across SD on Friday in tandem with a weak surface low. In response, south winds will strengthen across our area with sustained speeds of 10-20 mph with gusts of 20-30 mph. However, relative humidity will remain above critical thresholds, effectively limiting any wildfire threat. Temperatures will be warmer than today with readings in the upper 50s to low 60s. ...Saturday into Tuesday... A high-amplitude trough is forecast to evolve over the Interior West this weekend with that feature shifting east into the Great Plains on Monday. The 12z global models suggest that multiple, weaker disturbances will traverse the central Plains ahead of the main trough, the first of which will be on Saturday afternoon. Forcing for ascent preceding that lead system coupled with considerable moisture advection will support the development of showers and thunderstorms (PoPs increasing to 70-90%), which will spread from south to north over the course of the day. No severe weather is current expected. Additional, weak disturbances are projected to move through the region Saturday night into Sunday night with likely to definite PoPs (70-90%) during that time frame. The models hint at a surface warm front lifting north through the area on Sunday with dewpoints increasing into the 60s to the south of that boundary. That moisture increase combined with steep midlevel lapse rates could yield pockets of moderate instability amidst a modestly sheared environment along/south of the warm front with a few strong to severe storms appearing possible Sunday afternoon into evening. By Monday, the primary midlevel trough shifts east into the Great Plains (as mentioned above) with a surface cold front moving from west-to-east across the area. The setup currently appears somewhat analogous to yesterday's (Wednesday) event with some severe-weather potential developing along/ahead of the front. Showers could continue into Tuesday morning as the cold core of the midlevel trough moves through the region. Similar to yesterday's storm system, highest rainfall amounts are expected across the southern half of the area with latest NBM guidance suggesting at least a 70% chance of 1"+ along and south of I-80 in the Saturday-Monday timeframe. In regard to temperatures, forecast highs in the upper 50s to lower 60s on Saturday are expected to warm into the 60s to low 70s on Sunday as the warm front lifts north through the area. Readings on Monday will range from 60s ahead of the front to 50s behind it. Daytime temperatures are expected to remain in the 50s on Tuesday and Wednesday. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1148 AM CDT Thu Oct 31 2024 VFR conditions will prevail through the forecast period. West- northwest winds will continue to diminish this afternoon before switching to southeast this evening. Winds will strengthen to 12-14 kt by 15-16z Friday with gusts of 20-25 kt possible. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Mead AVIATION...Mead