FXUS63 KDMX 090803 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 303 AM CDT Fri May 9 2025 .KEY MESSAGES... - Isolated high based showers and thunderstorms across far northern Iowa this evening. Gusty outflow winds possible. - Dry with a gradual warming trend this weekend with highs in the 80s. - A pattern change is likely mid/late next week, which will bring our next chance for showers and thunderstorms. && .UPDATE... Issued at 302 AM CDT Fri May 9 2025 Sunny/mostly sunny conditions expected through afternoon due to influence of the sfc high centered over the Great Lakes. Highs today will be coolest in the southeast, low 70s, with mid 80s in northwest Iowa. This somewhat unique situation is due to the orientation of the thermal ridge. By late in the afternoon and into the evening, a weak upper trough/PV anomaly will move across the northern Plains. This will induce a sfc trough dropping sewd across SD/MN, reaching the IA border around 7pm this evening /00z Sat/. The latest 00Z guidance indicates that enough sfc and 0-2km moisture convergence will likely trigger isolated to widely scattered showers/tstms in that vicinity. Although MLCAPE values will be weak /100-400 J/kg/ forecast soundings indicate a pronounced inverted-V type profile. As these decaying showers/storms move into Iowa, its possible we'll see a few stronger wind gusts around 40 mph as indicated by the various CAM solutions /HRRR, NAMNest, RRFS/. Most of this activity should be along and north of US Hwy 18. Little to no rainfall is expected, as cloud bases are likely to be > 8000 ft, resulting in a virga-ish look. This pcpn activity should diminish pretty quickly after sunset and loss of insolation, with dry and quiet conditions returning overnight. && .DISCUSSION... Issued at 231 PM CDT Thu May 8 2025 Departing upper low is over MO/IL as of midday and becomes absorbed by the upper low in the northeast U.S. into tonight leaving upper ridging continuing to move into the area into Friday. At the surface, a Great Lakes high pressure also continues to move into the region into Friday keeping conditions dry and increasingly warmer. Have continued previous trend of decreasing afternoon dew points and warming high temperatures this afternoon and again on Friday with warmest temperatures on Friday in the northwest closest to the thermal ridge where highs reach into the low to mid 80s. Elsewhere, 70s still prevail to end the week. A weak northern stream shortwave and associated boundary (previously discussed a couple days ago) diving through MN on Friday afternoon kicks off some precipitation chances to the north of the IA/MN state line but the forecast remains dry in Iowa with ample dry air in place ahead of the line/boundary and overall minimal moisture to work with in soundings. Activity is also expected to decay with time as it progresses through MN with little in the way of instability remaining by the time the boundary arrives Friday night with generally weak shear. Can't rule out some outflow gusty winds reaching into far northern Iowa with the decaying showers/storms but forecast soundings and hi-res guidance are not particularly enthused about this possibility with gusts reaching up to maybe 30 knots for a brief time. Little change in the dry/increasingly warmer conditions is expected into the weekend with upper ridging remaining in place as an upper low churns over the Gulf Coast area. This low finally dislodges northward on Monday but looks to stay east of the area with any precipitation chances. A deepening western trough to start the work week moves eastward across some portion of the central U.S. into mid week but guidance remains highly variable in the track and thus associated precipitation chances but current longer range forecast brings some shower and storm chances Wednesday into Thursday with details to be further refined in the coming days. Temperatures largely in the 80s prevail Saturday and beyond with some locations northwest approaching upper 80s to even 90 on Sunday. Increasing winds out of the south will join these warming temperatures with near daily breezy southerly winds Sunday into next week. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1027 PM CDT Thu May 8 2025 Outside of a few high level clouds passing overhead at times, skies are expected to be mainly clear with VFR conditions throughout the period. Winds will remain light and variable as well. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Fowle DISCUSSION...05 AVIATION...Bury