066 FXUS63 KLBF 101940 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 240 PM CDT Mon Apr 10 2023 .SYNOPSIS... Issued at 219 PM CDT Mon Apr 10 2023 Key Messages: - Gusty southwest winds combining with afternoon humidity values as low as 10 percent will result in critical fire weather conditions on Tuesday. A Red Flag Warning is now in effect for all of western and north central Nebraska. See Fire Weather Discussion for more information. - Elevated to near-critical fire weather conditions exist on Wednesday across southwestern Nebraska. - Record high temperatures may be broken or tied on Tuesday and Wednesday as temperatures climb into the 80s with some locations nearing 90 degrees. - A late week storm system will bring cooler temperature and precipitation chances to western and north central Nebraska. Recent GOES-16 WV imagery and RAP 500-mb analysis showed an upper- level trough was noted off the coast of the Baja Peninsula. Further northeast of this feature, a broad upper-level ridge was located across the Desert Southwest extending across the much of the western CONUS into the Central and Southern Plains. An upper- level shortwave trough was evident across southeastern Kansas into northeastern Oklahoma. At the surface, low pressure was situated across eastern Kansas. Clear skies and tranquil conditions have encompassed western and north central Nebraska. At 2PM CT, temperatures ranged from 69 degrees at Gordon to 72 degrees at North Platte. && .SHORT TERM...(This evening through Tuesday night) Issued at 219 PM CDT Mon Apr 10 2023 A leeside surface trough will develop near the Front Range tonight. This will lead to south-southwest winds increasing overnight with gusts up to 25 mph in response to a tightening pressure gradient between the aforementioned leeside surface trough and broad surface high pressure situated across the Tennessee Valley. Quiet conditions will continue overnight with low temperatures being in the above normal range in the low to mid 40s under clear skies. As the surface high pressure strengthens and pushes further west, the pressure gradient tightens even further across the area leading to continued gusty southwesterly winds on Tuesday. Gusts of 25 to 35 mph will be common across western and north central Nebraska though a localized gust up to 45 mph cannot be ruled out. This is highlighted by the HREF ensemble which is emphasized by a 50 to 60% Probability of Exceedance of a 45 mph Wind Gust across portions of the northern Sandhills into portions of north central Nebraska. These gusty winds under clear skies will result in efficient mixing with southwesterly flow leading to summer-like temperatures knocking on our front door on Tuesday. Record threatening temperatures are expected across the area with temperatures climbing into the mid to upper 80s with some locations across northern Sandhills seeing 90 degrees. The signal for an anomalously warm event is supported by both the NAEFS and ECMWF ensemble guidance suggesting that the mean temperature at H85-5 will meet or exceed the 99th climatological percentile. Overnight lows on Tuesday may even threaten the maximum low temperature records for areas east of Highway 83. Lows in the 50s to near 60 degrees will be common for areas east of Highway 83 with lows in the 40s for areas west under clear skies. .LONG TERM...(Wednesday through Monday) Issued at 219 PM CDT Mon Apr 10 2023 An upper-level trough will push onshore of the PNW on Wednesday with broad upper-level ridging persisting across much of the central and southern CONUS. This will lead to another dry and warm day for western and north central Nebraska on Wednesday. Highs will climb into the 80s with readings of 90 expected for some locations across southwestern Nebraska. Similarly to Tuesday, the NAEFS and ECMWF ensemble continue to paint this anomalously warm event suggesting that the mean temperature at H85-5 will meet or exceed the 90th climatological percentile. In terms of fire weather concerns for Wednesday, minimum relative humidity values fall into critical thresholds across the western Sandhills into southwestern Nebraska leading to elevated to near- critical fire weather conditions. However, west southwest winds will remain light with peak gusts at 20 mph or less keeping the threat of critical fire weather conditions fairly low. Stronger southwest winds will be felt across areas east of Highway 83 with gusts up to 30 mph. However, minimum relative humidity values will be above 20 percent limiting fire weather concerns for those locations. The aforementioned upper-level trough will cross the intermountain west Wednesday night into Thursday. This will force a cold front to drop southeast across the region on Thursday stalling out across the northwestern half of the forecast area. Model solutions vary on just how far the front will push across the area leading to a challenging temperature forecast for Thursday. A decent temperature gradient will set up across the forecast area with a near 25 degree spread from far northwest to southeast Nebraska. Areas behind the front across the western and northern Sandhills, will likely see temperatures fall into the 60s to low 70s. In contrast, areas ahead of the front across southwestern and north central Nebraska, will see temperatures in the upper 70s to low 80s. Southerly winds will back towards the northeast with cold air advection (CAA) increasing behind the FROPA. In addition to CAA overspreading the area, precipitation chances increase Thursday night behind the advancing cold front and upper-level trough. Temperatures support rain being the predominate precipitation type for a majority of the area. However, overnight lows fall around or below freezing Thursday and Friday night for the Pine Ridge area into the western Sandhills which would support a transition to rain/snow mix and/or a brief snow shower. This is supported by WPC highlighting portions of the western Sandhills of seeing a 10 to 30 percent Probability of Melted Snow >0.25" for both Day 5 and 6. Confidence remains low in seeing impacts associated with any snow that does reach the ground given daytime highs on Friday and Saturday will climb into the 40s and 50s. Precipitation chances linger through Saturday evening before a return to dry conditions for Sunday. While this system will bring a good opportunity for rainfall, coverage will favor being scattered. WPC's QPF amounts range from 0.25" to 0.75" with the potential of 1" for some locations east of Highway 183. Confidence at this range in the forecast remains rather low in regards to rainfall amounts, especially given the spread amongst model solutions, however, expect the spread to narrow with subsequent forecasts. Regardless, Thursday night through Saturday evening has the best potential for wetting moisture to be seen across portions of western and north central Nebraska. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1243 PM CDT Mon Apr 10 2023 Expect VFR conditions across western and north central Nebraska over the next 24 hours. Winds will be from the south or southwest at 5 to 10 KTS today and tonight. They will then increase to 10 to 20 KTS Tuesday morning, with some gusts up to 30 KTS late Tuesday morning into Tuesday afternoon. && .FIRE WEATHER... Issued at 219 PM CDT Mon Apr 10 2023 For Tuesday, gusty southwest winds up to 35 mph combining with temperatures warming into the 80s to near 90 degrees will promote afternoon humidity values falling as low as 10 percent. This will result in critical fire weather conditions across western and north central Nebraska. A Red Flag Warning is now in effect for all fire zones from noon to 9PM CDT. For Wednesday, temperatures warm into the 80s across western and north central Nebraska. These warm temperatures will promote minimum humidity values to fall into the teens. With these warm temperatures and low minimum humidity values combined with southwesterly winds gusting up to 25 mph, elevated to near-critical fire weather concerns exist for Wednesday. For Thursday, elevated fire weather concerns exist with near-critical concerns for areas south of I-80. A cold front will cross the area during the day on Thursday bringing gusty southerly winds. There is still variations in just how far south the front will track which leads to some uncertainty in the extent of the elevated to near-critical fire weather conditions. For Thursday night and beyond, cooler weather should allow minimum relative humidity values to increase above critical levels which should lessen overall fire weather concerns. Additionally, precipitation chances increase Thursday night through Saturday evening bringing the potential for wetting moisture to portions of western and north central Nebraska. && .CLIMATE... Issued at 219 PM CDT Mon Apr 10 2023 Record highs may be tied to broken on Tuesday and Wednesday as an anomalously strong upper ridge begins to break down as an upper trough moves into the western U.S. Here is the record highs and (forecast highs) Tuesday and Wednesday for the four climate sites: Tuesday Wednesday North Platte 87 (85) 87 (85) Valentine 87 (91) 88 (83) Broken Bow 90 (82) 85 (83) Imperial 86 (86) 88 (86) && .LBF WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from noon CDT /11 AM MDT/ to 9 PM CDT /8 PM MDT/ Tuesday for NEZ204-206-208>210-219. && $$ SYNOPSIS...Viken SHORT TERM...Viken LONG TERM...Viken AVIATION...Buttler FIRE WEATHER...Viken CLIMATE...Viken/Roberg