FXUS63 KDVN 200520 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 1220 AM CDT Wed Aug 20 2025 .KEY MESSAGES... - A few isolated showers, and possibly a thunderstorm, is possible north of I-80 through tonight (10-15%). Patchy fog is possible late tonight into Wednesday morning. - Outside of a slight chance of storms late Friday into Saturday, drier conditions are expected through early next week. && .SHORT TERM /THROUGH THURSDAY/... Issued at 222 PM CDT Tue Aug 19 2025 Current satellite imagery shows cloud cover slightly breaking up across portions of the area, however weak northerly flow through the evening will lead to generally overcast skies continuing for the remainder of the day. A mid-level shortwave will track southward through the evening hours. Its associated forcing will be minimal across the area and although moisture parameters are still somewhat favorable with dewpoints near 70 and average model PWATs around 1.5 inches, this combined with relative stability due to the aforementioned cloud cover will inhibit any widespread thunderstorm development. High-res models continue to show a few isolated showers and possible thunderstorms this evening, mainly across our northern counties. In any case, severe weather is not expected. Some residual moisture will remain in place and thus fog remains possible around at the usual time before/after sunrise Wednesday morning. Highest chances would be again be across northern counties, particularly if any showers develop there later this evening. Anything should burn off fairly quickly and a pleasant day Wednesday looks to be in order with a building upper ridge to the west leading to drier conditions. Highs generally in the low-to-mid 80s are expected with gradually clearing skies in the afternoon. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Issued at 222 PM CDT Tue Aug 19 2025 An upper ridge building to the west will bring mostly dry conditions for the next few days. Surface high pressure over the Great Lakes will lead to weak easterly flow and hence relatively cooler and consistent temperatures into the weekend, with highs in the low-to- mid 80s along with partly-to-mostly clear skies. The next meaningful chance of precipitation will occur late Friday into Saturday. A 500 mb trough and its associated occluding surface low/cold front will track across the area during this time frame. Most large-scale models indicate a line of broken precipitation ahead of the front becoming more organized by Saturday morning as it makes its way into our area. Nonetheless, given the 3-day lead time, only chance PoPs have been retained in the latest forecast, but will likely increase as confidence grows. After the frontal passage, the upper level jet will dip well to the south by Sunday though early next week. A much stronger cold front may as well lead to further precipitation chances later Sunday, however confidence remains low. There is much higher confidence with regards to the significant cooling trend behind this front. Highs may struggle to reach 70s in some locations Sunday and Monday, with lows likely falling into the upper 40s. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1209 AM CDT Wed Aug 20 2025 Abundant low level moisture and calm winds will allow for fog to develop prior to sunrise, some of which could become locally dense. NBM probabilities of IFR conditions are now in the 30-50% range with highest values in southeast IA near BRL. Recent HRRR model is also trending more pessimistic in vsby restrictions. For these reasons, have included IFR/LIFR vsbys in the TAFs after 09z and will monitor trends this morning for any amendments. Conditions to rapidly improve to VFR after 14-15z, with a scattered Cu deck developing this afternoon and winds turning northeasterly under 10kts. Some hi-res models generate some showers along and east of the MS RVR this afternoon, but confidence too low to mention with this TAF cycle. && .CLIMATE... Issued at 256 AM CDT Tue Aug 19 2025 The latest Climate Prediction Center's 6-10 day and 8-14 day temperature outlooks has 60 percent or higher probabilities of below normal temperatures for the last week of August across the entire outlook area. Normal highs for this time of year are in the lower 80s and normal lows are in the upper 50s and lower 60s. This will be a very much welcomed change compared to recent days, even a taste of Fall perhaps! && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Previous Fcter LONG TERM...Previous Fcter AVIATION...Gross CLIMATE...Gross