Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/09/21

Area Forecast Discussion
National Weather Service Topeka KS
452 PM CST Mon Nov 8 2021 ...AVIATION UPDATE... .DISCUSSION... Issued at 233 PM CST Mon Nov 8 2021 Generally zonal flow is present across a majority of the CONUS this afternoon, outside of a positively tilted upper trough over the East Coast. A vorticity maximum over the Upper Midwest has pushed a weak cold front southward, currently stretching from northeast to southwest across the forecast area. Warm 850 mb temperatures, along with deep mixing and sunny skies, have allowed temperatures to quickly climb ahead of the front. Temperatures have warmed into the low 70s to the south of this front, with mid 60s present to the north. The front will stall just southeast of the area tonight and into tomorrow. While temperatures will be a bit cooler, the overall air mass will not be too much different behind the front. So lows tonight will still be in the mid 40s to low 50s, and highs tomorrow will still climb into the 60s. By late Tuesday and into Wednesday, the zonal flow will amplify as a jet streak over the eastern Pacific moves into the western CONUS. This will deepen a trough over the Rockies that will move into the Plains on Wednesday. In response, developing lee troughing and strengthening southerly flow will pull moisture northward into the area. Isentropic ascent along and north of our old frontal boundary, now lifting north as a warm front, will allow for a few showers to develop as early as Wednesday morning. As an elongated area of low pressure lifts northeast, a cold front will push eastward Wednesday PM. Additional showers and storms will develop along the cold front as this occurs. There may be just enough instability (300-500 J/kg of MUCAPE) for a few thunderstorms as well. The meager instability will keep the risk for severe thunderstorms low, with the main impact being a widespread rainfall. Total precipitation looks to be in the 0.5-1.0 inch range for many, as well as a few higher amounts where any thunderstorms can persist. Behind Wednesday`s cold front, a cool air mass will settle in for the end of the week and weekend. The upper trough will continue to amplify over the Midwest into a deep upper low, resulting in persistent CAA over the Plains. Highs should be in the mid 50s Thursday, dropping into the 40s for Friday as the strongest push of cold air moves in. A steady northwest breeze will drop wind chills into the 20s and 30s. Temperatures stay chilly into the weekend, though a gradual warming trend back into the 50s will occur as the upper low slowly moves farther away to the east. Precipitation chances remain too low to mention throughout this period, as moisture will remain limited under the northwest flow aloft. There may be a couple low end precipitation chances Friday and Sunday as a pair of weak upper systems slide southeast. However will keep out any mention of precipitation for now, given that moisture will remain limited under the northwest flow aloft. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday) Issued at 452 PM CST Mon Nov 8 2021 The NAM continues to be overdone with its low level saturation based on current conditions. So will maintain a VFR forecast based the the RAP and GFS progs and northerly winds behind the front advecting lower dewpoints south. Steepening low level lapse rates may lead to some CU developing Tuesday afternoon, but forecast soundings from the RAP and GFS show bases remaining above 3KFT. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...Reese AVIATION...Wolters