Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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099 FXUS63 KDVN 170545 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 1245 AM CDT Tue Sep 17 2024 .KEY MESSAGES... - High confidence on above normal temperatures this week. - Confidence on timing of rain chances late week into the weekend is low, as an upper level ridge becomes reestablished across the region. && .SHORT TERM /THROUGH WEDNESDAY/... Issued at 204 PM CDT Mon Sep 16 2024 This morning`s sounding showed that there is significant dry advection from previous days in our atmosphere, with notable dry layers found near 700, 500, and 400 mb. Measured PWAT values are down to 1.1", a drop from 1.6" just a day ago. Despite this drying out aloft, the low level moisture has been slow to drop, and dew point values remain in the lower to mid 60s in much of the CWA, except for the far east, which is now falling into the upper 50s. As of 1 PM, temperatures are in the lower to mid 80s, and highs of 87 to 90 look on track. The next 24 hours will continue to see a gradual drop in moisture, with the boundary layer eventually seeing dew points in the 50s by tomorrow morning, which could mix down to the low 50s Tuesday afternoon! Temperatures will be a degree or two colder tonight than last with the dry advection, and lows in the upper 50s to near 60 are forecast. Highs Tuesday appear to reach the upper 80s to near 90 once again. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Issued at 204 PM CDT Mon Sep 16 2024 A lingering Rex block in the eastern CONUS is progged to finally weaken early on, which is great news for our rain prospects right?!? Unfortunately, likely not so at least early on in the period, as the models quickly reestablish and amplify upper ridging over the region Wednesday and Thursday ahead of a western CONUS trough, and possibly longer. Trends from WPC cluster analysis of the 500 hPa pattern support the influence of the upper ridge holding on longer. NBM has pushed back PoPs to Thursday night through the weekend, but based on the cluster analysis and trends of the 500 hPa ridge strength and placement I wouldn`t be at all surprised to see further delay/slowing of the PoPs. As a result, confidence remains low with the timing of rain chances, until possibly sometime next weekend when there`s a signal for the ridge shifting eastward allowing for more influence of shortwave troughing. While timing of our next rain chances remains low confidence, what remains high confidence is a continuation of the unseasonable late summer warmth through at least late week. The 12Z WPC guidance now shows this weekend rain potential more over our CWA, but time will tell. There are many 12Z GEFS members that keep our area dry through the weekend. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 1235 AM CDT Tue Sep 17 2024 High pressure centered over the Great Lakes is brining quiet weather to eastern Iowa TAF sites. VFR conditions are forecast to prevail through the period. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Ervin LONG TERM...Ervin/McClure AVIATION...Cousins