Area Forecast Discussion
Issued by NWS Des Moines, IA
Issued by NWS Des Moines, IA
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289 FXUS63 KDMX 221935 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 235 PM CDT Sun Sep 22 2024 .KEY MESSAGES... - Light showers ending over the south. - Next chance of precipitation Monday night and early Tuesday far northwest and far southeast. && .DISCUSSION... Issued at 230 PM CDT Sun Sep 22 2024 Surface cold front is well south of Iowa this afternoon and over central portions of Illinois and Missouri. Drier dew points continue to filter into Iowa with values into the low 40s across the north. Values are still in the upper 50s across the south and there is a pseudo boundary just south of Interstate 80 now which appears to be near the edge of the deeper layer dry air. Some light showers will persist over the south before the lingering moisture and meager instability move off to the south. High pressure ridge will move from the west tonight and into Monday though mid to upper level clouds over the south will persist. There is some opportunity for radiational cooling over the north with temperatures dropping into the lower 40s with a few upper 30s in the valleys possible. Another short wave will lift through the Midwest Monday and Monday night with theta-e advection commencing over southeast Iowa and will bring a chance for a few showers and isolated storms to that portion of the state. Another short wave dropping southeast from the Dakotas could also bring a few showers into northwest and west central Iowa also late Monday night into Tuesday morning. That system will continue to descend south and deepens into an upper low over Iowa and Missouri on Tuesday and will bring the thermal trough over the state. Highs on Tuesday will be largely dependent on the amount of residual cloud cover the this upper low. That low will settle slightly father south and stall for much of the rest of the week while high pressure ridge tries to lean overtop. Iowa will be stuck in the middle with overall pleasant conditions with highs in the 70s and lows in the 40s and 50s. Late in the week and into next weekend, a tropical system is projected to come on shore over the Gulf coast and become ingested by the larger upper low, eventually leading to a shift back to the north with a wave of Gulf moisture lifting into Iowa around next weekend. This is still a low confidence period but something to watch for the potential next chance for precipitation. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1242 PM CDT Sun Sep 22 2024 VFR conditions are expected through the forecast period. Cigs near 4 kft remain near KOTM with cloud bases rising from north to south. Breezy to gusty north wind over northern Iowa today. All areas will have decreasing wind overnight and into Monday morning as high pressure arrives. The wind will gradually become east/southeast late tonight and early Monday. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Donavon AVIATION...Donavon