033 FXUS63 KDMX 091109 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 609 AM CDT Mon Jun 9 2025 ...Updated for the 12z Aviation Discussion... .KEY MESSAGES... - Areas of smoke to persist overnight - Breezy start to the week, shower chances (20-50 percent) north/northeast - First 90 degree temperatures of the year expected Wednesday - Next chance (60-70 percent) for more organized, widespread precipitation will be Wednesday afternoon, Wednesday night & into Thursday && .UPDATE... Issued at 210 AM CDT Mon Jun 9 2025 Initial cool front that passed through on Sunday is now well south of our area over central Missouri, and surface flow has come back around to west southwest across most of Iowa. However, clear skies and cooler air behind that front have allowed temperatures to fall into the low to mid 50s across the entire forecast area, resulting in an unseasonably cool night. Meanwhile, a second trough is approaching from the northwest and has already passed through Estherville and Mason City as of this writing. Brisk northwest flow is spreading in behind this second trough, along with a large cloud shield and some light rain. While the trough will surge completely through Iowa today, it will be losing its oomph and daytime mixing will limit the intrusion of the clouds and showers. Accordingly, have kept highest Sky and POPs in our northern and northeastern counties today. Initially only light showers and perhaps a few flashes of lightning are anticipated in the north early this morning, then these will push off to the east followed by a lull before additional showers and isolated thunderstorms develop with the diurnal maximum this afternoon. During both rounds, instability will be far too limited for any severe weather threat, and even thunder may be hard to come by. However, it will be a relatively cool and breezy day once again. Also of note is that any lingering near-surface smoke should clear out by sunrise this morning, but the HRRR continues to depict a stream of smoke aloft moving overhead today, so have incorporated that into the sky cover forecast as well. && .DISCUSSION... Issued at 232 PM CDT Sun Jun 8 2025 Weak "cool" frontal pushed any instability and thunderstorm chances south into MO earlier today. In its wake, forcing/moisture along the trailing H7 front has been enough to produce area of light rain showers this afternoon for areas along and south of Interstate 80. Amounts have been/will continue to be very light - perhaps as much as a few hundredths of an inch. Lift wanes and moisture departs this evening, and so too will the shower chances. Latest HRRR near-surface smoke output keeps smoke from Canadian wildfires thru the overnight for areas generally across generally the southern 2/3 of the state, with some dispersion towards morning. Otherwise the parent upper low near the Boundary Waters at the moment, will slowly dive southeast into WI by midday Monday, sliding another mid- level shortwave and associated "cool" front into northeast IA. Shower chances (20-50 percent) will be confined to mainly northeast counties as a result. Similar to today, limited lift/instability will result in any amounts being very light. Elsewhere conditions will be dry beneath partly cloudy skies along with northwest winds that will turn breezy with gusts of 20-30 mph common most places. The pesky upper low finally departs Monday night and Tuesday leaving dry northwest flow with temperatures rebounding as H85 warm-air thermal advection returning; and along with full insolation will boost temperatures back into the 80s and Tuesday and what will likely be the first 90s of the season for Wednesday. The next organized and more widespread rain chances return to Iowa beginning late Wednesday, continuing off and on through the end of the week. Latest model output stalls the warm frontal boundary somewhere across northern Iowa/southern Minnesota beginning late Wednesday, continuing into Thursday. PWATs increase to 1.5-2, which would put it at 90% of historical daily norms. All this to say that this will be favorable set-up for a swath of good rain near where the warm front ends up at. Instability will sufficient for severe potential as well, especially across northern Iowa on Wednesday afternoon/evening. Details will become more clear over the coming days. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 609 AM CDT Mon Jun 9 2025 Clouds are spreading in from the north this morning but most ceilings will be VFR today. The exception is a period of MVFR ceilings in northern IA this morning, which are included in the MCW TAF but not at FOD/ALO where the lower ceilings are possible but probability is too low (20%) for TAF inclusion. Similarly, isolated SHRA/TSRA possible at MCW and ALO this afternoon, but also only a 20% probability of occurrence (and even lower of impacts below VFR) at a given terminal, and thus not mentioned in TAFs. && .DMX WATCHES/WARNINGS/ADVISORIES...None. && $$ UPDATE...Lee DISCUSSION...Hahn AVIATION...Lee