Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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137 FXUS63 KTOP 301731 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 1231 PM CDT Tue Apr 30 2024 .KEY MESSAGES... - A period of active weather is expected starting this afternoon and continuing through Thursday with several chances for thunderstorms, including the potential for severe weather. - Additional rounds of thunderstorms could lead to heavy rainfall and the potential for flooding. && .DISCUSSION... Issued at 329 AM CDT Tue Apr 30 2024 Early this morning a 700 mb trough was progressing eastward out of Colorado into western Kansas at 08Z. Scattered mid level showers have developed within the nose of the 700mb warm advection. In addition profilers and water vapor show small weak perturbations that will move across eastern Kansas early this morning. The scattered high based showers may have some lightning at times as they progress eastward. They should come to an end by mid morning in northeast Kansas. Focus then turns to this afternoon as a mid level trough begins to move across the northern and central Plains then into the upper midwest later this evening. A mass response ahead of the wave and associated cold front with dewpoints increasing into the lower 60s this afternoon. General consensus with short term convective allowing modes is for storms to develop across Nebraska and Iowa this afternoon, with storms developing along the cold front and dryline in central Kansas with additional development into northeast Kansas by late afternoon. Forecast soundings and hodographs support all modes of severe weather this afternoon and evening with large hail perhaps 2 inches or higher, 70 mph wind gusts and tornadoes. The line of storms will move southeast through northeast and east central Kansas this evening with the front and convection then stalling across southeast Kansas. Given this scenario will hold off on a Flood Watch for now with the heaviest precipitation expected to be near the Oklahoma border. Highs today will warm into the low to mid 80s. Later tonight looks quiet with the convection expected to remain south of the forecast area over southern Kansas. However this will be short lived as the front moves northward on Wednesday in response to another mid level wave moving eastward across the Rockies and low pressure deepening on the lee of the Rockies in southeast Colorado. The front is forecast to lift into southern Nebraska or far northern Kansas during the evening. Dew points in the 60s will spread northward behind the warm front across the area. Convection is expected to develop near the warm front from south central into northeast Kansas early and looks to be elevated with mainly a hail threat. Also good moisture flux into the region will also lead to efficient precipitation with rainfall rates of 1 to 2 inches per hour possible. By late afternoon storms may develop off the dryline taking on supercell characteristics. The environment will be favorable to all modes of severe weather once again with large hail around baseball size, damaging winds to 70 mph and with good turning in the lower atmosphere where effective SRH of 200-250 M2/S2 is forecast would support strong tornadoes. Locally heavy rainfall looks to set up Wednesday night into Thursday morning with training cells along and ahead of the frontal boundary with in a PW axis of 1.5 inches, a theta axis bisecting the cwa from southwest to northeast and strong moisture transport. This period will need to be monitored for a future flood watch as well. The mid level trough will move across the central Plains during the afternoon hours Thursday and into Thursday evening. Additional storms may develop along the frontal boundary over eastern Kansas in the afternoon and evening hours. A continued risk for severe weather and locally heavy rainfall is expected. Additional waves moving through the flow across the Plains will bring continued chances for precipitation this weekend into early next week. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1231 PM CDT Tue Apr 30 2024 Several aviation hazards over the TAF, first with winds this afternoon and later with thunderstorm concerns. Winds will remain gusty this afternoon out of the south, gusting upwards of 30 mph. A frontal boundary moving in from central Nebraska will develop convection around the terminals between 22-00z this evening, with better confidence in convection at KTOP and KFOE. Storms will likely develop near KMHK and quickly move east. Following the cold frontal passage, winds will shift to the northwest, becoming calmer into Wednesday morning. Some rain and thunderstorm chances will increase late Wednesday morning and into the afternoon as a warm front pushes north. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...53 AVIATION...Griesemer