226 FXUS63 KOAX 140435 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1135 PM CDT Sun Apr 13 2025 .KEY MESSAGES... - Very high to extreme fire danger today and Monday with 30 to potentially 50 mph gusts at times (especially Monday). A Red Flag Warning is in effect for northeast Nebraska today, with another in effect for most of the area Monday alongside a wind advisory. - Spotty rain chances tonight and again Monday afternoon (20% chance). Some showers/storms Monday afternoon could produce 55+ mph gusts. - Higher shower and storm chances (20-50%) Wednesday into Thursday. - Another chance for rain and a few storms (30-40%) this upcoming Sunday. && .DISCUSSION... Issued at 342 PM CDT Sun Apr 13 2025 Today and Tomorrow: Water vapor imagery this afternoon depicts a digging shortwave trough pushing across the Northern Plains while troughing off the Atlantic Coast continues to release its influence on the eastern CONUS and ridging arrives over the western third. A recent surface analysis shows a prefrontal trough/wind shift already passed through the forecast area into Iowa while a cold front continues its push across eastern Nebraska and far western Iowa, arching from the Wayne southwest to far northwest KS. Gusty winds and low relative humidity values have been settling in behind the prefrontal trough, and have been driving very high to extreme fire danger that maxes out over northeast Nebraska. Sunny skies have allowed temperatures to hold on before cooling too fast where lowering dewpoints have keep RH values low and around 35%. Winds should stay stead through the early evening and into the overnight hours, with temperatures falling and limiting the low RH values by 03z, which is when the current Red Flag Warning for northeast Nebraska ends. Lows overnight should bottom out in the low-to-mid 40s, with those winds keeping any spot from getting too cool locally. For Monday, we`ll see winds at multiple layers of the atmosphere peak during the afternoon, where gusts of 40 to 50 mph are possible while sustained winds reach 25-35 mph. A Wind Advisory is in effect for those winds, and will join relative humidity values falling into the 18-25% range thanks to very deep mixing to about 650 mb. The combination of those dry conditions and winds has a Red Flag Warning in effect for 1 to 9 PM. At the top of that mixed layer, about 50- 100 J/kg of MUCAPE will glance northeast Nebraska and western Iowa, and any showers that do form with that instability should be able to push down very strong winds, potentially of 60+ mph. As of right now, the chances of those showers or weak storms is about 20-30% during the afternoon hours. Tuesday and Beyond: Tuesday will see winds releasing their grip on the area thanks to high pressure that dips southward during the afternoon hours. Despite the cooler airmass, we`ll have highs climbing into the mid- to-upper 60s to make for a beautiful spring day. Wednesday will have additional warming as a warm front pushes northward through the forecast area. Soundings do show some moistening of the lowest 350 mb, but is inconclusive on how much lift there will be to make anything of it (with the ECMWF being the main supporter of rain). Our next bigger ticket item will come Thursday as the system that brought the Wednesday warm front has a shortwave push through the area. The main question with this system will be how much lift will be present in the 700-800 mb range, and whether it will jump start a storm out of the 1000 J/kg of CAPE. Strong shear and little-to-no access to the lower hodograph points towards hail and wind being the main concerns this far out, with a 15% severe outlook also highlighting this area for the afternoon hours. We`ll also see our warmest temps of the forecast period topping out in the mid-to-upper 80s. Friday onward will see a cutting off mid/upper low squat over the southwestern CONUS Friday before springing out to the northeast through the forecast area into the weekend. The exact timing of this ejection will be very important, as the tilt of the system will become increasingly negative and more daylight as the forcing moves across the forecast area will lead to increased severe potential. An ECMWF-favored solution would be timed best for severe weather, with ML severe guidance based on it showing severe chances maxing out at 30% in far southeast Nebraska. For now, we`ll keep and eye on it, there`s plenty of time for track and timing shifts to occur. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1135 PM CDT Sun Apr 13 2025 VFR conditions favored for much of the forecast, though could see a brief period of MVFR ceilings in northeast Nebraska Monday morning, including at OFK. Otherwise expect northwest winds to continue gusting 30-35 kts before coming down a bit Monday evening. Can`t completely rule out an isolated stronger gust in northeast Nebraska/west-central Iowa with some showers or an isolated storm, but they`ll be spotty with highest chances staying north of OFK. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...Wind Advisory from 11 AM to 9 PM CDT Monday for NEZ011-012- 015>018-030>034-042>045. Red Flag Warning from 1 PM to 9 PM CDT Monday for NEZ011-012- 015>018-030>034-042>045-050>053-065>068-078-088>093. IA...Wind Advisory from 11 AM to 9 PM CDT Monday for IAZ043. Red Flag Warning from 1 PM to 9 PM CDT Monday for IAZ043-055- 069-079-090. && $$ DISCUSSION...Petersen AVIATION...CA