169 FXUS63 KTOP 280938 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 338 AM CST Sat Dec 28 2019 .SHORT TERM...(Today and tonight) Issued at 334 AM CST Sat Dec 28 2019 As of 09Z Saturday morning a deep midlevel trough extended along the Central and Southern Rockies. Water vapor imagery reveals a plethora of midlevel moisture overspreading the region -- this will set the stage for record PW later today with values reaching 1.00-1.25". A band of rain showers extends from the TX Panhandle through western IA as height falls overspread the Plains with the approaching trough. At the surface, strong low level WAA was ongoing across southern KS as a warm front slowly pushes northward. At this hour, the front extends from west TX to near KHUT to just south of EMP and becoming more diffuse as you travel east from there. Areas south of the front have seen dew points surge into the 40s and 50s. The front will continue to lift northward through the day with the entire forecast area seeing dew points reach the low to middle 50s. Confidence is high for an expansion of the precipitation field through the day with 100% chance of rain area-wide today. The primary concerns today are with the threat for damaging winds and potentially brief tornadoes. Short and mid range guidances continues to suggest as the main trough ejects into the Plains an arc of shower and thunderstorm activity should develop on the Pacific front across southern KS and northern OK near midday. Tremendous deep layer shear, characterized by 120-140 kt 300 mb speed max, will progress rain and thunderstorm activity rapidly to the northeast at 50-60 MPH. With modest backing of low-level winds ahead of the Pacific front, a tremendous amount of low-level SRH will be in place. This adds the potential for damaging winds and tornadoes. The main caveat is just how much destabilization we see this afternoon. Short range guidance continues to suggest that any rain shower activity should remain isolated through the morning and early afternoon, which could result in sufficient surface heating to foster surface based effective inflow and a resultant damaging wind and tornado potential. The most favorable zone for damaging winds and possibly tornadoes looks to remain along and southeast of the KS Turnpike, where the highest low- level theta-e should reside. Otherwise, the anomalously high PW values should result in moderate to at times heavy rainfall through the afternoon and evening. Still thinking rain totals should range 0.75" to 1.50" with locally higher amounts near 2". .LONG TERM...(Sunday through Friday) Issued at 334 AM CST Sat Dec 28 2019 Transitioning into Sunday, mid range guidance has increased the potential for snow showers. As the midlevel trough rotates through the region, sufficient moisture and ascent should remain in place for snow showers, especially along and north of I-70 through the day Sunday. Furthermore, steep low-level lapse rates could briefly enhance snowfall rates. Overall, thinking any accumulation should remain light with a dusting to 1/2 inch possible. Beyond Sunday, quiet weather should return to the area through midweek before a midlevel low ejects across the Southern Plains Thursday into Friday. At this point, the best potential for precipitation looks to remain south of the forecast area. Temperatures look to steadily warm through the week with highs returning to the 40s and 50s. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1150 PM CST Fri Dec 27 2019 VFR conditions at FOE and TOP should be brief as lower levels continue to saturate ahead of a surface low and developing warm front. IFR conditions should be the rule by 10Z in low cloud with more persistent showers again looking to be a bit slower. Could see visibilities drop to LIFR ahead of and between the showers as well. Conditions should improve late in the forecast but timing and speed of these increases is uncertain. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Baerg LONG TERM...Baerg AVIATION...65