768 FXUS63 KTOP 251742 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 1142 AM CST Mon Feb 25 2019 ...Update to aviation forecast discussion... .SHORT TERM...(Today and tonight) Issued at 304 AM CST Mon Feb 25 2019 The short-term forecast period will see increasing clouds and a drastic temperature gradient from south to north across the forecast area. Little else in the way of sensible weather though. An intense upper level trough and associated winter storm system is now situated over the central Great Lakes into the New England region of the country. Split flow pattern set up over the rest of the CONUS with only minor waves working through the Pacific Northwest and one more notable wave translating through the southern Rockies. This zonal flow over the Rockies will continue to support lee troughing and weak cyclogenesis meandering out of southeastern portions of Colorado into the Texas panhandle region. Any movement of the system will be impeded by stronger surface ridging to the east extending into the Mississippi Valley and Ohio Valley regions. This overall set up puts northeast KS right in the middle of the transition zone. As the lee low tries to develop but finds upper level support too ill defined to become much, a warm front will sharpen as colder air to the north begins to interact with warmer air to the south with slight WAA nosing into east central Kansas. Morning lows start out cold with some wind chill readings reaching as low as -10 to -15 degrees near the KS/NE border thanks to the recent snowfall over the region. Further south over east central areas, high cirrus is keeping temps up around 20 degrees. As the warm baroclinic zone does meander into the area and develop into this afternoon, low level stratus should develop especially over areas along and north of I-70. Fewer clouds and deeper mixing over east central areas will help temps reach near 50 in contrast with the high temperatures generally along the KS/NE border only reaching around 20. Exact position of the boundary appears to be the difference between having near normal temps to much below normal values. Still very wide spread and thus variability amongst guidance even at this hour, so have a strong temperature gradient from south to north across the area for today. There could even be a few flurries over northern areas during the overnight time frame tonight as temperatures within a shallow saturated layer of stratus support ice nucleation to become activated with slight ascent along the 285K isentropic surface. Have not gone with flurry mention at this time in the public weather grids however, since the supporting layer could be shallow and thus remain only stratus considering the overall weak ascent. Morning temperatures Tuesday look to reflect Monday's gradient with single digits over northern and north central areas while points south into east central KS see temperatures around 20 to middle 20s. .LONG TERM...(Tuesday through Sunday) Issued at 304 AM CST Mon Feb 25 2019 A nearly zonal flow is expected across Kansas from Tuesday through Friday. Weak waves are forecast to move across the central Plains through this period. The polar jet will remain across the northern states while the subtropical jet will move across the southern Plains. Tuesday a frontal boundary is forecast to move into east central Kansas allowing for a wide temperature gradient from northwest to southeast across the cwa. Temperatures are expected to vary from around 20 near the Nebraska border to the upper 40s southeast of I-35. Low level moisture will begin to return northward into east central and northeast Kansas as weak isentropic upglide ensues through the day. Moisture transport vectors increase Tuesday evening across east central Kansas and into Missouri. Low level frontogenetic forcing and continual theta advection in the 290K-295K layer and presence of a PV anomaly moving through the mid level flow should be sufficient for the formation of light precipitation beginning Tuesday afternoon and continuing through Tuesday night. Surface temperatures will dictate precipitation type between drizzle and freezing drizzle. Expecting only a light glazing of a few hundredths of an inch or less. Any untreated surfaces may be slick in spots. A stronger trough moving out of Canada and into the Great Lakes on Wednesday will push an arctic high southward into Kansas along with dry cold air advection. This will push the baroclinic boundary south into Northeast Oklahoma and Arkansas. This will limit any precipitation to mainly across east central Kansas Wednesday and Wednesday night. Another mid level wave is forecast to move through Wednesday night and thermal profiles would support some sleet and perhaps some light snow along with the freezing drizzle Wednesday night. Precipitation chances return for the end of the week and into the weekend. Models still showing some variance in timing and the amplification of the mid level wave as it moves across the Plains. The GFS is the more amplified solution with the CMC and ECMWF less and focused further northward across Nebraska. All scenarios may lead to precipitation across parts of the CWA Friday and Friday night. Thermal profiles would suggest that it will be cold enough for light snow for areas north of I-70 on Friday with a mix south transitioning to all snow Friday night before ending. Confidence is low this weekend for another clipper Saturday night which may bring some light snow with it, due to model divergence. One thing that has had a consistent signal is that temperatures will be much below normal for early March. Could see some wind chills in the teens below zero Saturday night. Highs Saturday and Sunday are expected to be in the teens and 20s for highs each day. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1142 AM CST Mon Feb 25 2019 MVFR stratus over north-central Kansas gradually builds eastward into tonight, reaching MHK around 06Z and TOP/FOE closer to 12Z. There is some uncertainty in how quickly the stratus fills in and there is a chance that it arrives sooner. A warm front is currently south of a line from MHK to TOP, with winds from the E/NE to its north and from the south to the south of this line. Winds become NE area-wide tonight. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Drake LONG TERM...53 AVIATION...Skow