603 FXUS63 KDMX 101124 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 624 AM CDT Thu Apr 10 2025 ...Updated for the 12z Aviation Discussion... .KEY MESSAGES... - Scattered light showers and perhaps a few thunderstorms today, mainly in the afternoon and evening. Heavy rain and severe weather are not expected. - Warm and breezy this weekend, with highs in the upper 60s to lower 70s on Saturday and well into the 70s on Sunday. Shower and storm chances forecast across northern Iowa around Sunday morning. - Breezy on Monday, otherwise dry and quiet early next week with highs in the 50s and 60s Monday through Wednesday. && .DISCUSSION... Issued at 140 AM CDT Thu Apr 10 2025 A 500 mb trough is dropping southeastward over Minnesota early this morning and will broaden over the Great Lakes and Ohio River regions later today through tonight. An weak surface low associated with this trough will sink across eastern Iowa today, bringing clouds and scattered showers to most of our service area by the afternoon and evening. Even this morning a few sprinkles or light showers will linger around, but coverage will increase by the early afternoon as the surface low approaches and will likely linger into tonight before fading out. Forecast soundings show some meager elevated instability mainly over southeastern Iowa later today and a few thunderstorms will be possible, but severe weather and heavy rain are not anticipated. Have lowered forecast temperatures today just a bit in our eastern and northeastern counties to account for thicker cloud cover, but highs will still range in the mid 50s northeast to mid 60s southwest. On Friday the 500 mb ridge will begin to move away to the east, and a surface high pressure area will build across Iowa. The result will be light winds, gradually clearing skies, and generally pleasant spring weather with highs ranging in the upper 50s to lower 60s. Meanwhile, a deep-layer thermal ridge will build over the Rockies and High Plains and subsequently slide eastward over Iowa on Saturday, bringing gusty southerly breezes and notably warmer weather as temperatures climb into the upper 60s to lower 70s on Saturday afternoon. A compact 500 mb low will then move eastward over the far northern U.S. in the latter part of the weekend. A surface trough will develop around South Dakota/Nebraska as this system approaches, sliding near northwestern Iowa late Saturday and Sunday morning and bringing a return of rain chances to our northern counties during that time. However, the bulk of the forecast area will remain southeast of this zone with gusty southerly breezes and warm air advection continuing, pushing temperatures well into the 70s Sunday afternoon. For now have held off on cooling temperatures in the north/northwest or warming them further in the central and south, due to uncertainty regarding the precise location and impact of the surface trough. The 500 mb low moving across the far northern states will finally cross Minnesota and push the surface trough through Iowa sometime around Sunday evening, bringing an end to the weekend`s warm weather and ushering in a northwesterly steering flow regime for the remainder of next week. Within this regime we typically expect an alternating series of surface high and low pressure, some precipitation chances at times, and fluctuating but non-extreme temperatures and the extended forecast bears that out, with rain chances returning around the middle of next week and highs from Monday through Wednesday generally in the 50s and 60s across Iowa. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 624 AM CDT Thu Apr 10 2025 Isolated light showers are moving across the area early this morning but any visibility/ceiling reductions associated with them are marginal and brief. Meanwhile a bank of low stratus and fog is producing MVFR visibilities and IFR ceilings just east of our area, but affecting ALO at this time. A front moving through the area will sweep these out within the next hour or so. Later today, mainly this afternoon and evening, showers will become somewhat more widespread and have maintained PROB30 groups for MVFR conditions therein but amendments are likely based on short-term observational trends. Prevailing MVFR ceilings may also affect MCW/ALO for a period later today into tonight even outside of the showers. && .DMX WATCHES/WARNINGS/ADVISORIES...None. && $$ DISCUSSION...Lee AVIATION...Lee/Jimenez