138 FXUS63 KTOP 292141 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 341 PM CST Sat Dec 29 2018 .SHORT TERM...(This evening through Sunday) Issued at 325 PM CST Sat Dec 29 2018 This afternoon an upper low was located along the southeast AZ and Mexico border. A shearing out positive tilt upper trough extened northeast into the upper Midwest. Weak ascent ahead of positive tilt H5 trough across KS has resulted in mid level cloud cover across the eastern half of the state. The western edge of the mid clouds extended from Hiawatha, southwest to Herington early this afternoon. The clearing line will gradually shift east across the CWA through the afternoon hours as the weak positive tilt upper trough shift east across the central plains. Tonight through Sunday, the upper low across southeast AZ will dig southeast into northern Mexico, then lift northeast into southwest TX late Tonight. A lee surface trough will deepen across the southern high plains and will cause southerly low-level winds to develop across the CWA Tonight through Sunday evening, which will result in WAA and highs reaching the mid to upper 40s on Sunday. Cloud cover will begin to increase through the afternoon hours as residual moisture begins to advect northward. .LONG TERM...(Sunday night through Saturday) Issued at 325 PM CST Sat Dec 29 2018 Sunday night through Monday, the upper trough across southwest TX will lift northeast into AR and southern MO by Monday afternoon. Most numerical models continue show a light precipitation region to the northwest of the upper trough moving northeast across east central KS after midnight and through the morning hours of Monday. Modified moisture return along with weak isentropic lift will cause light rain to develop south of I-35, and temperatures may remain above freezing keeping the precipitation in the form of light rain southeast of I-35 through Monday morning. Temperatures may web bulb cool to freezing or a degree or two below freezing, allowing the light drizzle to change over to freezing drizzle northwest of I-35, northward through the I-70 corridor. Areas west of a Hiawatha to Council Grove will remain dry during the early morning hours of Monday. The light freezing drizzle may cause slick roads along the KS turnpike Monday morning but temperatures will warm above freezing during the mid morning changing the freezing drizzle over to drizzle during the late morning and early afternoon hours. A more amplified upper trough will dig southeast across the central Rockies into the northern high Plains early Monday morning. Strong low-level CAA across the northern and central high Plains will cause a surface cold front to move southeast across the northern counties during the mid and late morning hours and across the remainder of the CWA through the early to mid afternoon hours. The 12Z NAM forecast soundings show saturated soundings up to 850mb behind the front along with some weak isentropic lift. Therefore, directly behind the front there could be some patchy freezing drizzle across north central KS during the late morning hours and southeast across the remainder of the CWA during the afternoon hours of Monday. As the colder air deepens the patchy freezing drizzle will change over to snow flurries before ending during the evening hours. Monday evening (New Years Eve) through Tuesday (New Years), expect cold conditions, with temperatures dropping through the 20s into the teens by Midnight. Northwest winds of 15 to 20 MPH with higher gusts will cause wind chill indices to fall into the single digits to below zero along the NE border. During the early morning hours of Tuesday, low temperatures will fall into the single digits along the NE border with lower to mid teens across the remainder of east central KS. Minimum wind chill indices will drop to 10 to 12 degrees below zero along the NE border to around 5 below zero across east central KS. The winds should gradually decrease through the afternoon hours of Tuesday but remain in the 10 to 15 MPH range through most of the afternoon. Highs will only reach the upper teens along the NE border to the mid 20s across east central KS. Wind chill indices will range from the single digits to lower teens through the afternoon hours. Tuesday night through Wednesday night, the center of a 1036 mb surface ridge axis will move southeast across eastern KS late Tuesday night into Wednesday. The trough across the central Rockies and northern plains will continue to shear apart with the more amplified portion of the southern stream H5 trough digging southeast into west TX Wednesday afternoon, then moving east- northeast across north central TX and eastern OK. The residual moisture and ascent ahead of the southern stream H5 trough will remain south of the CWA, so expect dry but cold conditions. Overnight lows Tuesday night will drop into the single digits and lower teens. Highs on Wednesday may moderate a bit with lower to mid 30s expected. Thursday through Saturday, a broad upper level ridge across the western US will slowly shift east into the plains by Saturday. Expect a warming trend as zonal flow across the central Rockies will cause a lee surface trough to deepen. Southerly winds and WAA will cause highs to warm into the mid 40s Thursday afternoon and lower 50s Friday and Saturday afternoon. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) Issued at 1143 AM CST Sat Dec 29 2018 Expect VFR conditions through the next 24 hours. West-northwest winds under 10 KTS will gradually veer to the southwest this afternoon and diminish to under 5 KTS this evening. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Gargan LONG TERM...Gargan AVIATION...Gargan