824 FXUS63 KLBF 091845 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 145 PM CDT Tue Oct 9 2018 .SYNOPSIS... Issued at 314 AM CDT Tue Oct 9 2018 H5 analysis from earlier this evening had high pressure located off the coast of the Mid Atlantic states and a second high pressure noted around 1500 miles west of the nrn California coast. Between these two features, a broad trough of low pressure extended from southern Canada through the four corners, into northwestern Mexico. East of the trough, embedded shortwaves were noted and extended from New Mexico into eastern Colorado. Satellite imagery overnight indicated a nice area of thunderstorms extending from the Big Bend of Texas, north into the Texas Panhandle. Other showers were present from southwestern Kansas into southeastern Nebraska. Across western and north central Nebraska overnight, skies were cloudy with some patchy drizzle. Temperatures ranged from the middle 30s across the northwestern forecast area, to the middle 40s in the eastern forecast area. && .UPDATE... Issued at 1213 PM CDT Tue Oct 9 2018 A blend of the HRRR, RAP and HREF models suggests a more aggressive approach to the impending winter weather tonight. A check on cameras at Burwell and Broken Bow shows a rain snow mix underway and this changeover from rain to snow is several hours faster than any of these models predicted. The new forecast expands the winter weather advisory east significantly and places Cherry county in a winter storm warning where 6 inches of snow is forecast to fall tonight. && .SHORT TERM...(Today and tonight) Issued at 314 AM CDT Tue Oct 9 2018 Precipitation chances and snowfall potential tonight are the main forecast challenges this forecast period. For today: The shortwave, responsible for showers and thunderstorms over west Texas currently, will migrate north into western Kansas this morning. Showers will lift north into southern and southeastern portions of the forecast area this morning, spreading north and northwest into the afternoon hours. By late this afternoon, the main shortwave will lift into western Kansas with precipitation encompassing most of the forecast area. The shortwave trough will track through the forecast area tonight, with precipitation ending in the southern and central forecast area by 12z Wednesday. As for precipitation type, cross sections taken across the central and northwestern sandhills indicate a nice area of enhanced lift extending from Valentine to Imperial late this afternoon and this evening. Thermal profiles indicate temperatures cold enough for snow late this afternoon into the evening hours along and west of a line from Imperial, to Tryon to Ainsworth. Additionally, the forecast cross sections indicate some possible convective enhancement from far swrn into north central Nebraska this evening which would favor a quick burst of snow. Utilizing a blend of QPF from national guidance and the GFS soln, yielded a swath of 1 to 3 inches of snow from Imperial to Valentine tonight. The NAM12 soln seemed too high on its qpf forecast upon initialization and was disregarded for this fcst. Even utilizing the fcst qpf from the GFS soln would yield snowfall amounts in the 2 to 6 inch range. Given the warm ground conditions (measured soil temps in the upper 40s) in these areas, settled on the 1 to 3 inch range for snow accums. That being said, will leave the inherited winter weather advisory in effect for the western sandhills and portions of north central Nebraska, mainly for snow accums of 2 to 3 inches. Will word fcst locally up to 4 inches to allow for any moderate to briefly heavy snow band, which may develop. .LONG TERM...(Wednesday through Monday) Issued at 314 AM CDT Tue Oct 9 2018 Drier and quieter weather returns on Wednesday as high pressure starts to build into the region. The exception will be where a few lingering rain or snow showers are possible across the extreme northern counties. All rain chances will move out of the region by Wednesday afternoon with cloudy skies prevailing. There is a low chance of some patchy frost across much of the forecast area on Wednesday night as temperatures drop to near or below freezing. However, have refrained from adding it to the forecast at this issuance as clouds will help to limit frost development. Will need to reevaluate frost development at the next forecast issuance. High pressure will fully engross the region by Thursday keeping dry conditions around. The next chance of precipitation arrives on Thursday night. Current thinking is that precipitation will remain all rain south of a line from Ogallala to O'Neill. North of this line, a brief change over to snow is possible with minimal snow accumulations. Precipitation moves out of the region by Friday morning as high pressure builds back into the area. Dry weather will continue through Saturday before the next chance of rain/snow arrives Saturday night. Accumulations are uncertain at this time as confidence in the track and development of this system is low. Temperatures will gradually rise from the mid 30s and low 40s on Wednesday into the low 50s by Saturday. Colder temperatures return on Sunday after the cold front passage. Expect highs only in the upper 30s to low 40s. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 139 PM CDT Tue Oct 9 2018 Widespread MVFR and local IFR ceilings can be expected the next 24 hours across all of western and north central Nebraska. Widespread precipitation in the form of rain and snow will also continue. Northerly surface winds with gusts greater than 20 kt are also expected. && .LBF WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 9 AM CDT /8 AM MDT/ Wednesday for NEZ004-006-008-009-022>026-035>037-056>059-069-070. Winter Storm Warning until 9 AM CDT /8 AM MDT/ Wednesday for NEZ005-094. && $$ UPDATE...CDC SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Kulik AVIATION...Taylor