Area Forecast Discussion
Issued by NWS Des Moines, IA
Issued by NWS Des Moines, IA
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450 FXUS63 KDMX 160439 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 1139 PM CDT Sun Sep 15 2024 ...Updated for the 06z Aviation Discussion... .KEY MESSAGES... - A few showers and isolated thunderstorms mainly south and east into early this evening. - Mainly dry with above normal temperatures this week. - Pattern change expect late this week and into next weekend. && .DISCUSSION... Issued at 236 PM CDT Sun Sep 15 2024 Another day and little change in the overall going forecast outside of the typical delayed progress by the mid to late portion of the week. Widespread cumulus development has occurred this afternoon as temperatures in the low to mid 80s are near convective temperatures. Proximity soundings show some weak capping is holding just above the cumulus base level and is helping hold convective potential in check. A fragment of energy from Francine remnants is lifting into southeast Iowa this afternoon and evening, the overall kinematic forcing is low but there is some convective bubbling going on over that portion of the state. A few weak showers and thunderstorms will remain possible across that area into early this evening. As mentioned, little has changed going forward. The pseudo Rex block is undergoing a transition as a non-tropical low moves over the Carolinas tonight and this low will eventually absorb the remnants of Francine during the day Monday. This will lead to a further deepening upper low that will move very slowly over the eastern CONUS much of this week. Out west, another deepening upper low is diving south over Oregon and northern California this afternoon. That system will eventually eject northeast while another deep upper low dives south along with west coast. Eventually the other system will move east towards the end of the week. What does this all mean for Iowa. For the most part, weak high pressure ridging will remain intact across much of the area this week with above normal temperatures and generally dry conditions. Will note that the overall trends with this entire setup is a bit further west and delayed meaning less precipitation chances mid-week. The first system lifting northeast will bring some modest kinematic forcing into far western Iowa but as noted, the shift a bit west will diminish the areal coverage for precipitation chances into central Iowa. This shift includes that Gulf moisture stream north which is trending more into eastern Nebraska as opposed to western Iowa. Much of central and eastern Iowa likely will remain dry through the work week before the stronger system finally breaks the pattern stalemate over Iowa. This should bring cooler Fall like temperatures sometime next weekend and greater precipitation chances. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1138 PM CDT Sun Sep 15 2024 Confidence is medium-high that VFR conditions should continue through the period. Areas of high cloudiness should persist overnight, mainly north and east. FEW-SCT diurnal cumulus development is again anticipated Monday afternoon with dissipation into Monday evening. && .DMX WATCHES/WARNINGS/ADVISORIES...None. && $$ DISCUSSION...Donavon AVIATION...Small