409 FXUS63 KTOP 120450 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 1150 PM CDT Mon Mar 11 2019 ...Update to aviation forecast discussion... .SHORT TERM...(This evening through Tuesday) Issued at 339 PM CDT Mon Mar 11 2019 Tonight through Tuesday, An amplified upper low off the northwest Mexico coast line will move northeast into south central AZ by 00Z WED. Southwesterly mid level flow across the central Rockies will continue to deepen a lee surface trough across the central and southern high Plains. The resulting southerly low level winds across the southern and central plains will advect richer modified gulf moisture north-northwest across the southern plains. Later tonight as the richer moisture begins to advect northward at 850mb across OK into southern KS, isentropic lift will increase for light rain to develop from southwest to northeast across the CWA after Midnight. Several numerical model solutions forecast most of the rain along and north of I-70 may end for a while Tuesday afternoon. The NAM and ECMWF show a minor perturbation and vort max embedded in the southwesterly flow aloft lifting northeast across OK into southeast KS after 18Z TUE. This may provide enough ascent to keep rain across east central KS, south of I-70 through the afternoon. QPF through Tuesday should remain below 0.25" as most of the ascent will be due to isentropic lift. Ahead of the upper low in the southwest US, H5 heights may rise a bit downstream across the Plains on Tuesday. Overnight lows will occur during the evening hours with mid 30s along the NE border and lower 40s elsewhere, but temperatures should begin to warm through the early morning hours as the low-level WAA increases. .LONG TERM...(Tuesday night through Monday) Issued at 339 PM CDT Mon Mar 11 2019 Tuesday night through Wednesday, The upper level trough will lift rapidly northeast into northwest KS by 00Z THU and amplify, as an upstream H5 trough digs east-southeast and phases with the with the upper trough lifting northeast across southwest KS on WED. A strong H5 jet max of 110 KTS will lift northward ahead of the upper trough and provide strong ascent in the left exit region of the jet across eastern KS late Tuesday night into Wednesday morning. There will also be stronger DCVA ahead of the amplified trough which will enhance the ascent across central and eastern KS. Meanwhile, a deep surface/850mb low across southeast CO WED morning will allow for the advection of richer gulf moisture to surge northward across central and eastern KS, with surface dewpoints reaching the mid to upper 50s across the eastern half of the CWA by the morning hours of Wednesday. PWs will be around 1.5" by 12Z WED morning. The heaviest rainfall will occur late Tuesday night through the morning hours of Wednesday. The MUCAPE may increase to about 300-400 J/KG, which may cause some elevated thunderstorms Tuesday night into Wednesday morning. The total QPF ranges from around 1.6 inches across north central KS to around 1.20 inches across east central KS. I expanded the flood watch to include Geary and Dickinson Counties, this flood watch may need to be expanded farther east during the next couple of shifts. Several models show a 700mb dry slot lifting northeast across eastern KS after 18Z. The NAM model shows some potential clearing Wednesday afternoon and enough low-level moisture for 500-1000 J/KG of MLCAPE developing across south central and central KS, ahead of the Pacific front by 21Z. If surface based thunderstorms develop along the Pacific front across central KS, a few could become strong to severe given 0-6KM shear of 30 to 50 KTS. If the NAM verifies there could be a few low top supercells which may reach the western counties of the CWA during the late afternoon hours. However, the stronger vertical windshear may not allow surface based updrafts to develop due to the weaker instability. The instability axis does not extend east due to cloud cover and MLCAPES across the central and eastern counties of the CWA will be under 200 J/KG. Highs on Wednesday ahead of the Pacific front will reach the mid 60s across the southwest counties and may be a few degrees higher if there is more insolation. Highs across the remainder of the CWA will be in the lower 60s. Wednesday night into Thursday, the upper low will lift northeast into southeast NE. A surface low over west central KS late Wednesday afternoon will track northeast across north central KS into southeast NE and will deepen to 984mb along the NE KS border by 12Z THU. West to northwest winds will increase to 25-35 MPH during the early morning hours of Thursday across north central KS, then spread southeast across the remainder of the CWA. The surface low will fill as it lifts northeast, vertically stacked below the H5 low, thus we may not see 50 MPH to 60 MPH wind gusts west of the TOP CWA across western KS early Thursday morning. Scattered light wrap around rain showers will be possible Wednesday night into Thursday, but as the upper low lifts into southwest WI, the wrap around showers across eastern KS will dissipate after 00Z FRI. Low-level CAA across the CWA will only allow highs to reach the lower to mid 40s. It will feel colder with the strong northwest winds. Friday through Monday, northwesterly flow at mid levels will continue across the plains. This will keep highs in the 40s through Saturday with a slow warming trend into Sunday and Monday with highs in the 50s. Expect dry conditions. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1142 PM CDT Mon Mar 11 2019 VFR stratus gradually spreading east towards KTOP/KFOE with ceilings gradually lowering to MVFR by 12Z as the rain showers lift northward towards terminals. Rain may be heavy at times, but overall trends are holding off on IFR stratus until the tail end of the precip in the 16Z to 18Z time frame. Low end MVFR to high end IFR stratus persists through the forecast period with scattered rain showers through 06Z. LLWS was inserted for the first few hours of the forecast period based on VAD wind profiles showing 40 kts at 1000 feet from the southeast with light easterly winds. && .TOP WATCHES/WARNINGS/ADVISORIES... Flood Watch from Tuesday evening through Wednesday evening for KSZ008>011-020>023-034>036. && $$ SHORT TERM...Gargan LONG TERM...Gargan AVIATION...Prieto