819 FXUS63 KTOP 120843 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 343 AM CDT Sun May 12 2019 .SHORT TERM...(Today and tonight) Issued at 343 AM CDT Sun May 12 2019 Overnight water vapor imagery depicts an upper trough centered over eastern portions of South Dakota and Nebraska making southeast progress. A shortwave ahead of the main trough was producing a wide band of showers and an occasional thunderstorm over the northeast quadrant of Kansas with up to around half an inch of reported in recent hours. Other more isolated convection was nearer the trough center. Weak surface wind fields and some patchy clear skies between these areas of precipitation were allowing for patchy fog to develop. Can't completely rule out a similar occurrence in mainly north central Kansas early this morning but mid cloud is making a fast return to this area per IR satellite trends. The current main area of showers should exit around sunrise but additional isolated to scattered development/advection is likely by midday as the main upper trough continues southeast and interacts with several hundred J/kg of ML CAPE forms with diurnal heating and additional shortwaves rotate around the trough. With a very similar airmass moving in but better mixing, expect highs to be a few to several degrees warmer than Saturday. The loss of daytime heating should bring and end to most precip by early evening as a weak surface high builds into northwestern Missouri. Clear skies behind the wave and light winds over re-wetted ground may allow for fog development as suggested by many guidance products, and have included patchy mention for most locations. .LONG TERM...(Monday through Saturday) Issued at 343 AM CDT Sun May 12 2019 By Monday, meridional mid-level flow will be in place over the central U.S. with a trough centered over the Great Lakes region and a ridge stretched across the western U.S. At the surface, high pressure will progress further east of the CWA, with southerly winds supporting WAA to boost afternoon high temperatures into the low/mid 70s. The mid-level ridge will amplify through mid week as a mid- level trough deepens over the Pacific Ocean. A few embedded disturbances may develop within the northwesterly flow aloft of the mid-level ridge Tuesday into Wednesday, resulting in the potential for some scattered precipitation chances. Surface low pressure will advance into western KS through mid-week, with steady southerly winds supporting continued WAA to push high temperatures into the low/mid 80s Tuesday into Wednesday. This southerly flow will also support steady moisture advection with dewpoints reaching into the 60s. With these conditions in place, decent destablilzation should occur through the day Tuesday with 2000-3000 J/kg of MUCAPE possible along with roughly 30kts of 0-6km bulk shear. However, the surface cold front doesn't look to sink southeastward into north central to far northeast KS until late Tuesday night/early Wednesday morning. Once the front advances into the area to provide some forcing for thunderstorm development, cannot rule out the potential for a few strong to marginally severe elevated thunderstorms. However, there are still significant model discrepancies with the potential development and coverage of thunderstorms, so will need to continue to monitor these conditions for Tuesday night. Additional isolated shower and thunderstorm development may continue into Wednesday as embedded disturbances continue to develop within the mid-level flow. However, dry conditions look most likely from Wednesday night through Friday night as the mid-level ridge traverses eastward across the central U.S. Southerly surface winds will prevail through the end of the week, so expect high temperatures to remain in the low/mid 80s. By Friday/Friday night, models show the mid-level trough axis extending toward the Four Corners region before pivoting northeastward toward the Central Plains on Saturday. This advancing trough will push an area of surface low pressure eastward into western KS, with the CWA looking to remain in the warm-sector through the day Saturday. As a result, the combination of continued warm, moist-air advection into the region ahead of an advancing surface cold front should allow for decent destabilization through the day to support thunderstorm development during the afternoon/evening hours. While this system is still a week away, it looks to be the next best chance for more widespread strong to, possibly, severe storms, so we will be continuing to closely monitor this system through the upcoming week. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) Issued at 1151 PM CDT Sat May 11 2019 A line of showers will move across the terminals early this morning. I cannot rule out a very isolated thunderstorm withing this line. I did not have confidence to place TS in the TAFs. Low stratus with ceilings around 3000 feet may develop ahead of and behind the surface front when it passes through between 11Z and 13Z SAT. Isolated showers may redevelop Sunday afternoon but should dissipate during the late afternoon and early evening hours. The strato CU should remain above VFR criteria. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...Hennecke AVIATION...Gargan