Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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205 FXUS63 KTOP 051905 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 205 PM CDT Fri Jul 5 2024 .KEY MESSAGES... - Chance of thunderstorms tomorrow afternoon, some of which could be severe. - Frequent thunderstorms will pose a risk of flooding through Sunday. - Below average temperatures will continue through the middle of next week. && .DISCUSSION... Issued at 203 PM CDT Fri Jul 5 2024 Northwest flow continued to keep a cooler and drier airmass in place for this afternoon. High temperatures were forecast in the low to mid 80s, slightly below average for this time of the year. A low amplitude shortwave could be identified on satellite imagery, with enhanced convection and cold cloud tops in northwestern KS. This impulse will travel across the state, bringing a slight chance of rain this afternoon and evening. However, with dewpoint depressions near 40 degrees F, it is expected that rain will not be able to reach the surface. A stronger disturbance was seen on water vapor imagery upstream in southern Saskatchewan/eastern Montana. This wave will track to the SE overnight and tomorrow, and will foster development of a surface low pressure in western Kansas. Warm air advection will strengthen, and our high temperatures will approach 90. As the system gets closer, convection is likely to form in central KS/southern NE. Eastern KS will not have a very supportive environment for severe weather, with CAPE values struggling to reach 1000 J/Kg as a result of the drier airmass in place at the surface. That being said, well established thunderstorms will be capable of producing damaging wind gusts as they move SE across the state. Most models indicate that the higher severe wind threat will be south and west of a line from Concordia to Salina, where convergence along the boundary is stronger. Multiple more waves rounding the base of the trough will continue into Sunday, and frequent thunderstorms are likely during the day. As a result of the extensive cloud cover, highs will only be around 80 on Sunday. Moisture is going to increase, and the threat for flooding will increase somewhat on Sunday. Some areas south of I-70 have received over 400% of their average 14-day precipitation, suggesting that soils are very saturated already. This weekend, those areas south of I-70 have a moderate (40-60%) chance of exceeding 1 inch of rain, according to the NBM. The trough axis is forecast to pass on Monday, bringing an end to the rain chances. This will reinforce the cooler air, giving us another day with high temperatures right around 80. This trough is likely to keep Beryl and its associated moisture away from Kansas. As the upper air pattern becomes less active, temperatures should warm up and become closer to average, with upper 80s through the middle of next week. The next trough passage suggested by the models is Wednesday overnight, and that is when the chance of thunderstorms will return to the forecast. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1157 AM CDT Fri Jul 5 2024 VFR conditions will prevail through the period. This afternoon, gusty northwesterly winds to 20 kt will continue. Diurnal cumulus will form, and promptly dissipate by sunset. After sunset, a high pressure system will pass to the south, and light winds will turn from NW to S/SW. The light winds may lead to patchy fog, but confidence is low. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Montgomery AVIATION...Montgomery