522 FXUS63 KTOP 071744 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 1244 PM CDT Sun Apr 7 2019 ...Update to aviation forecast discussion... .SHORT TERM...(Today and tonight) Issued at 334 AM CDT Sun Apr 7 2019 Early this morning the mid-level trough axis was pivoting northeastward across the outlook area. While the main line of showers and storms exited to the east early this morning, another batch of scattered showers and storms on the backside of the trough axis was tracking into north central KS. There is still uncertainty with regards to whether or not this scattered precipitation will be able to sustain itself across the CWA, but it's worth noting that 06z and 07z runs of the HRRR/RAP show it holding together and tracking eastward along the I-70 corridor through sunrise before dissipating. As a result, have kept some slight to low-end chance PoPs in the forecast through that time. Where precipitation has cleared out, areas of fog have developed due to last evening's rainfall and the calm winds in place. Reduced visibilities of 1/4 mile to 1 mile have been common, so will need to continue to monitor these reduced visibilities to see if areas of dense fog become widespread enough to warrant the need for a Dense Fog Advisory. While models show the surface cold front still tracking eastward across the CWA this morning, model soundings do not show much in the way of residual moisture behind the exiting mid-level trough. As a result, have trended a little faster with diminishing PoPs and have a dry forecast by mid morning. While surface winds should veer to the west and northwest late morning through this afternoon, there doesn't look to be much in the way of colder air behind this front. As a result, expect deep enough mixing to occur to once again boost high temperatures into the middle 70s across much of the CWA as skies become mostly sunny through this afternoon. Surface high pressure will quickly track south of the area tonight into Monday, causing winds to back to the southwest once again. However, these winds will be very light, so combined with mostly clear skies anticipate decent radiational cooling to support cooler temperatures with lows into the mid/upper 40s. .LONG TERM...(Monday through Saturday) Issued at 334 AM CDT Sun Apr 7 2019 A weak front associated with a modest wave moving across the northern Plains passes through in the afternoon but should have little impact on highs reaching the middle to upper 70s with only some afternoon cirrus to hinder insolation. Model differences begin to increase Tuesday with differences in handling shortwaves rotating around an eastern Canadian low impacting how fast the modest surface ridge exits to the east and local low-level winds. With cirrus likely to increase downstream of the approaching upper trough, this could have notable impacts on temps. An average approach produces highs in the mid 70s to lower 80s. Solutions with the faster exit to the low-level ridge bring the entire area well into the warm sector of the developing cyclone Wednesday while northern and western locations struggle to see deep mixing in the slower solutions. Plenty of mid-level warm-air advection Tuesday into Wednesday keeps surface-based convection unlikely with the associated front's/fronts' passage Wednesday into Thursday so the main impact with the warm sector location Wednesday will be on wind speeds (possibly near Advisory levels) and thus fire weather with Very High RFD category possible in a better-mixed scenario. The system is now back to a more progressive state and brings strong cold-air advection Wednesday night into early Friday with much greater potential for deformation precipitation to impact at least northern locations as well as more Wind Advisory potential as the roughly 985 mb low exits to the east-northeast Wednesday night into Thursday. The CAA results in snow potential (likely light) in northeastern areas as the precip exits Thursday night. Temperatures both Thursday night and Friday night could pose a hazard to early vegetation with lower 30s quite possible. There is fairly good model agreement in the next upper wave emerging from the southwestern states next weekend. The window for temperatures to recover significantly bring some concern for mixed precipitation again. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 1236 PM CDT Sun Apr 7 2019 At TAF issuance time, a batch of MVFR CIGS continued to impact the TOP terminals. Further scattering and lifting to VFR conditions is expected by 20Z. A weak front is moving through northeast KS, which will cause winds to veer to a northwesterly direction early this afternoon. Gusts of 20-25 kts are possible. Some conditions tonight look favorable for radiational fog development, however, confidence is not currently high enough to include in TAFS. Will monitor for possible inclusion in the next TAF period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Hennecke LONG TERM...65 AVIATION...Teefey