Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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181 FXUS63 KDVN 161910 CCA AFDDVN Area Forecast Discussion...CORRECTED National Weather Service Quad Cities IA IL 210 PM CDT Fri Aug 16 2024 .KEY MESSAGES... - Chances of showers and storms will accompany an upper-level low that will remain anchored over the western Great Lakes through late Saturday - A Marginal Risk for strong to severe storms remains over far northwest Illinois this afternoon and early evening - A dry pattern develops for next week, with seasonal temperatures && .SHORT TERM /THROUGH SATURDAY/... Issued at 205 PM CDT Fri Aug 16 2024 After abundant sunshine this morning, we are beginning to see some diurnal cumulus clouds percolating over our region, particularly across our northern areas as a PVA maxima dives southeastward towards our area on the southern side of a vertically stacked upper- level low currently over northern Wisconsin. The main concern with this approaching trough will be increasing chances of showers and thunderstorms this PM, especially for areas north of Interstate 80. Convective parameter space appears to be less favorable for strong to severe storms compared to yesterday, with MLCAPE values up to 1000 J/kg and 0-6 km shear 25 to 35 knots progged, so a more marginal environment for strong storms. SPC has maintained a Marginal Risk (level 1 of 5) for severe storms later on over far northwestern Illinois, mainly for a wind/hail threat. This activity should linger into the evening hours before dissipating due to increasing atmospheric stability. Calmer conditions are expected tonight once any lingering showers and storms diminish, but the aforementioned upper low will slowly slide southeastward toward Lake Michigan Saturday, leading to increasing clouds tonight and more chances of showers and storms on Saturday. With the closer proximity of the upper low, there is a low potential for funnel cloud development from some of the showers. RAP NST values are fairly meager, with values no greater than 1, which suggests a pretty low risk of funnels. However, I wouldn`t rule it out entirely of seeing some funnels under the stronger showers/storms. Otherwise, instability and shear appears to be more meager compared to today, so we are not outlooked for any strong/severe storms. Temperatures are looking pretty seasonal overall tonight and Saturday, with highs Saturday in the upper 70s to lower 80s and tonight`s lows in the lower to middle 60s. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Issued at 205 PM CDT Fri Aug 16 2024 Although there will be lingering chances of showers and a few thunderstorms Saturday evening, much of the long-term forecast period should rather quiet and seasonal. The upper-level low over the western Great Lakes will finally exit the region to the east Saturday night, which will lead to a quieter pattern for us. The WPC cluster analysis indicates a very consistent signal among the GEFS, EPS, and CMCE ensembles that a large upper- level omega blocking pattern will develop on Sunday over the central CONUS and linger through at least Thursday. Upper-level ridging will become established over the Front Range of the Rockies, placing our region under an area of subsidence. This will keep our pattern dry and quiet. Additionally, temperatures will remain seasonal, with daytime highs in the upper 70s to lower 80s, and overnight lows in the 50s to lower 60s. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1223 PM CDT Fri Aug 16 2024 VFR conditions were observed across the area as of TAF issuance. We are tracking an approaching trough of low pressure from the northwest, which will bring increasing chances of showers and perhaps a few storms, mainly for areas north of the Highway 30 corridor. At this time, it appears most likely for DBQ to see some showers, but confidence is a bit lower on thunderstorm coverage, so we have kept that out of the DBQ TAF for now. If storm coverage becomes greater than expected, a TEMPO group for the storms would likely be needed. Otherwise, some gusty westerly winds and increasing cloud cover are expected this afternoon. As the system approaches from the north, expect ceilings to lower tonight into Saturday morning, with MVFR/IFR cigs likely. Some patchy fog can`t be ruled out late tonight, but confidence remains low on coverage at this time. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Schultz LONG TERM...Schultz AVIATION...Schultz