Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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474 FXUS63 KTOP 121742 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 1242 PM CDT Sun May 12 2024 .KEY MESSAGES... - Isolated showers and thunderstorms this morning into afternoon, then rain becomes more widespread tonight into Monday morning. - Showers and storms continue on and off through Monday. Many places are forecast to receive over 1" of rainfall by Tuesday morning, with some places possibly up to 2". - Another system is expected to bring chances for showers and storms Wednesday through Friday morning. && .DISCUSSION... Issued at 356 AM CDT Sun May 12 2024 08Z water vapor imagery shows a mid-level shortwave trough digging over the Four Corners region early this morning. Another closed low is noted over northern Manitoba about to move into Ontario, while a low-amplitude wave can be seen off the coast of British Columbia. At the surface, weak low pressure has begun to develop in eastern CO in response to the aforementioned shortwave. Dew points across the forecast area are in the upper 40s to low 50s, with 60-degree readings still as far south as central OK. Rain showers have been slowly working their way through western KS early this morning with thunderstorms confined to the TX/OK panhandles so far, where the better instability resides. There may be enough isentropic lift this morning to bring some isolated, hit- or-miss shower activity into the area. However, the best large-scale lift and moisture transport with the approaching shortwave looks to arrive late this afternoon, mainly moving through this evening and overnight. This is when CAMs show rain becoming more widespread over the area. Based on the latest guidance, there should be some breaks with dry time during the day on Monday, but generally expect showers and a few storms to continue on and off. The rain looks to taper off toward Monday evening as the trough axis pushes east. Generally speaking through these two days, MUCAPE looks limited to under 1000 J/kg with 0-6 km bulk shear around 20-30 kt, so the chance of any embedded thunderstorms becoming severe looks low. Ensemble data shows most areas are likely (60-80%) to see at least 1" of QPF by Tuesday morning with lesser confidence for any particular point to see upwards of 1.5". That said, ensemble plumes across the area do show a decent number of solutions between 1.5 and 2", suggesting there could be some pockets of amounts such as these. This idea is supported by the HREF as well. We look to get a break from the rain on Tuesday before the next Pacific trough moves through the area Wednesday through Friday. There are still some differences among models regarding the timing and strength of this system, so it is unclear at this time whether we dry out before Friday, but PoPs remain in the forecast through Friday for now. Adjustments can be expected as we get closer to that time frame. Instability and shear look similar to the first system, so not anticipating severe weather at this time, but again it will be something to monitor. Clouds and rain will likely be the main influence on temperatures for much of the week. Highs are generally forecast in the upper 60s to low 80s this week, with temperatures expected to be on the lower end of that range on the days with more cloud cover and rain. Forecast lows are mainly steady in the 50s. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1239 PM CDT Sun May 12 2024 A few isolated showers may develop this afternoon around the terminals. Widespread showers will move across the terminals after 01Z and continue through the night. There may be a few elevated thunderstorms this evening. As the steadier rain moves in, wet-bulb cooling will lower the stratus bases below 2000 feet. The steady rain should move off to the east after 10Z. But showers and low MVFR or IFR ceilings will prevail into Monday morning. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Picha AVIATION...Gargan