FXUS63 KTOP 140900 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 300 AM CST Thu Nov 14 2024 .KEY MESSAGES... - Sunny skies and above normal temperatures are expected through Saturday. - Rain and a few thunderstorms are expected Sunday night into Monday. - There may be a chance for light snow showers Wednesday night into Thursday morning. Though confidence is low. && .DISCUSSION... Issued at 241 AM CST Thu Nov 14 2024 Early this morning an upper level trough was located across the mid and lower MS River Valley. A second upper level trough was located just off the west coast of the US. A surface ridge of high pressure was located across the central and southern high Plains. Today through Saturday: The H5 trough off the west coast will move onshore Tonight and then translate east into the Great Basin and southern CA. Expect a slight warming trend into Saturday as a downstream H5 ridge amplifies across the Plains and then shifts east across the east central US by Friday night. The upper trough across the western US will shear apart late Saturday with the northern stream H5 trough moving east into the northern high Plains and the southern stream section of the H5 trough digging south-southeast into northwest Mexico. Stronger southwest flow across the the central Rockies will cause a lee surface trough to deepen Friday into Saturday. Southerly winds will help temperatures to warm into the mid 60s on Friday, with highs reaching the mid to upper 60s on Saturday. Saturday night through Sunday: As the northern stream H5 trough shifts east across the northern Plains into the upper Midwest, low-level CAA across the northern Plains will cause a surface front to push southeast across most of the CWA Friday night into Sunday morning. There may be a few rain showers along or just north of the front late Saturday night into Sunday. Late Sunday afternoon the surface front will become stationary across the southern counties of the CWA. Sunday night through Tuesday night: The southern stream H5 trough will lift northeast out of northern Mexico into western TX by 12Z MON by an upstream kicker H5 trough moving onshore across northern CA. An 850mb low will develop across the TX PNHDL and the strong southerly 850mb winds of 40 to 50 KTS across the southern Plains will advect richer gulf moisture northward across the stationary front across the southern counties of the CWA. The resulting isentropic lift and stronger ascent ahead of a 90 KT H5 jet max will cause widespread rain and elevated thunderstorms to develop across the CWA during the night. The rain and thunderstorms will continue through the day on Monday as the H5 low tracks north-northeast across western OK into north central KS by 00Z TUE. The surface warm front will lift northward during the the day on Monday, up to the NE border, but due to the widespread rain and elevated thunderstorms the chances for surface based storms look low. The vertical windshear will be strong on Monday but low and mid level lapse rates will not be steep. Thus instability looks marginal for severe thunderstorms on Monday. Highs Sunday and Monday will be in the mid 50s to lower 60s. Monday night the H5 low will continue to track northeast into IA and fill a bit. A 700mb dry slot and surface front moving east of the area will provide a break from the precipitation on Tuesday. Highs on Tuesday will be in the 50s. The H5 trough across the western US will dig southeast into the southwestern US late Tuesday. Wednesday through Thursday: The H5 trough across the southwest US will amplify into a closed H5 low and will begin to lift northeast across southern NM into west TX early Wednesday. As the upper low approaches DCVA and isentropic lift will cause light rain to redevelop and move northward across the CWA. The upper low will then track northeast across east central KS by Thursday morning. Strong low-level CAA on the west side of the H5 low will cause the light rain to mix with or change to light snow late Wednesday night across the CWA. Too early to give any amounts but there could be a dusting of snow in some areas. There are differences in the extended range models. The GFS is more progressive and less amplified with the upper low. The GFS solution shows stronger low-level CAA Wednesday night, which would change the light rain over to snow. The ECMWF is slower lifting the upper low northeast across east central KS. The ECMWF is warmer Wednesday night with most of the area only seeing lows in the mid 30s to around 40 degree, which would keep more of a light rain precipitation type. However, the TROWAL looks more developed on the ECMWF model and there will be cold air advection through the day on Thursday, with temperatures slowly falling into the 30s, which will cause the rain to change over to snow across north central and northeast KS. If the ECMWF verifies the light snow and rain may continue into Thursday night. I'm sure the extended range models will change over the next several runs. The Canadian model is in more agreement with the GFS model. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1020 PM CST Wed Nov 13 2024 Stratus has exited to the east of the terminals and dry air continues to work east into the area which along with a partially mixed BL overnight minimize the chances for any fog to form. Winds will relax through the morning and into the afternoon before gradually becoming more southerly and remain below 10kts through the end of the period. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Gargan AVIATION...Drake