746 FXUS63 KOAX 211743 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1243 PM CDT Wed Mar 21 2018 .SHORT TERM...(Today through Friday) Issued at 301 AM CDT Wed Mar 21 2018 Water vapor imagery as of 08z depicted a coupled of weak mid-level perturbations within the general area: one over our CWA and the other traversing the Dakotas. Both features will shift east today in deference to a longer-wavelength ridge which will amplify over the Rockies. In the low levels, a surface ridge axis from the ND- MN Red-River Valley to mid-MO Valley will build east while a lee trough deepens along the Front Range. This will result in light and variable winds gradually becoming south or southeast by afternoon. IR satellite data indicate patchy stratus over our eastern NE counties with more widespread cloudiness across southwest IA. Model guidance suggests a gradual clearing trend today from southwest to northeast across the area. Highs will range from the lower to mid 50s at locations that will experience more sun to upper 40s in west-central IA. Tonight, the development of a nocturnal low-level jet will focus a zone of warm advection and isentropic upglide over far eastern NE into western IA with isolated to widely scattered showers possible toward daybreak Thursday. On Thursday into Thursday night, the aforementioned mid-level ridge to our west will build into the Great Plains while a surface low deepens over eastern WY. While low-level winds will remain light and from the east or southeast, clouds should decrease through the day allowing temperatures to warm into the mid 50s to mid 60s. On Friday, a progressive short-wave trough will move into the central High Plains by afternoon and through the mid-MO Valley Friday night. In response, a surface low will consolidate over western KS prior to tracking into northwest MO by Saturday morning. Strengthening southerly winds ahead of the cyclone will draw and warmer and more moist air mass into the region with showers developing within the associated warm-advection regime on Friday. Highest precipitation chances will exist across our northern counties, decreasing with southward extent toward the KS border. Highs will be dictated by the cloud/precipitation distribution with generally cooler readings in the north and warmer afternoon temperatures in the south. .LONG TERM...(Friday night through Tuesday) Issued at 301 AM CDT Wed Mar 21 2018 By Friday evening, the co-location of steep mid-level lapse rates, a moistening low-level air mass, and deep-layer forcing for ascent immediately ahead of the synoptic cyclone will yield a weakly unstable environment with scattered non-severe storms possible across southeast NE and southwest IA. Precipitation chances should decrease from west to east across the area on Saturday with the passage of the weather system to the east. By Sunday into Sunday night, we will see an increase in precipitation chances within a zone of warm advection associated with a short-wave trough lifting through the northern High Plains. On Monday into Tuesday, 00z medium-range guidance indicates that an upper low will cutoff over the southwestern U.S. with an associated surface front slowly sagging south through the central Plains. This setup will favor continued precipitation chances with some light snow possible across the northern half of our area Monday night. High temperatures through the extended range should generally be in the 40s and 50s. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1238 PM CDT Wed Mar 21 2018 VFR conditions are likely through the TAF period with a very small chance for visibility restrictions to develop late tonight but have currently kept VFR TAFs due to the low potential for fog. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Mead LONG TERM...Mead AVIATION...Barjenbruch