Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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928 FXUS63 KDVN 151721 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 1221 PM CDT Sat Jun 15 2024 .KEY MESSAGES... - A quiet start to the weekend expected with mostly dry conditions through this afternoon. - Scattered showers and storms are possible tonight into Sunday morning, favored across the northwest portion of the forecast area. - Hot weather is expected Sunday through Tuesday with peak heat indices between 95 to near 100 degrees. Forecast temperatures drop by a few degrees for the middle to end of the week. && .SHORT TERM /THROUGH SUNDAY/... Issued at 315 AM CDT Sat Jun 15 2024 Today and Tonight GOES WV imagery showed a shortwave trough over eastern Colorado and a large MCS across portions of eastern Nebraska into north- central Kansas. As of early this morning, SPC Mesoanalysis had the MUCAPE gradient draped across eastern NE into northwest MO with no instability locally where dewpoints are in the 50s to upper 40s. CAMs are generally in good agreement on the Central Plains convective line to weaken as it approaches central to eastern Iowa. There are low chances for showers and isolated storms through the day mainly across the west and northwest counties, but forecast soundings are showing a dry sub-cloud layer. For this reason, much of the area is expected to stay dry through the afternoon/evening. Temperatures will range from the low 80s north to mid/upper 80s central and south, with comfortable humidity expected. As the mid-level shortwave glances the area late tonight, a period of scattered showers and storms is possible, especially across the northern portion of the forecast area. NBM rain chances range from near 20% along I-80 to 40-60% north of Highway 30. The HREF has MUCAPE increasing to near 1000-1500 J/kg with 30+ kts of deep layer shear, which could support a few strong storms with gusty winds the primary threat. Latest SPC outlook has a Marginal Risk for severe storms along and west of a Manchester, IA to Cedar Rapids to Memphis, MO line. Sunday Scattered showers and storms may linger north of I-80 during the morning hours before shifting east and dissipating. Otherwise, hot and humid conditions are expected with highs in the low to mid 90s and peak heat indices between 95 to near 100 degrees, highest south of I-80. Subsidence behind the departing shortwave should result in mainly dry conditions across the outlook area for the afternoon. A surface low tracking near Lake Superior will lead to breezy SW winds locally with gusts around 30 mph, providing some relief from the hot conditions. The resultant boundary layer mixing should hold dewpoints in the 60s and prevent much of the area from reaching Heat Advisory criteria, aside from on an isolated/brief basis. EC and GFS ensemble mean 850mb temps near 21 C are in the 95-97th percentile and have a return interval of 1 or more days per year, suggesting this is not an extremely unusual event. Fairly confident in highs topping out in the low to mid 90s for most areas; much lower confidence on locations reaching the upper 90s as shown by the NBM 50th - 75th percentiles. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Issued at 315 AM CDT Sat Jun 15 2024 Monday - Tuesday: Hot weather continues early in the week with forecast highs in the low to mid 90s (isolated upper 90s possible on Monday). Dewpoints will be the main player in whether locations hit Heat Advisory criteria (100 F). The NBM has been consistent with afternoon dewpoints in the mid/upper 60s, yielding peak heat indices on Monday between 95 to the lower 100s, and a little lower on Tuesday. An increasing surface pressure gradient between low pressure over the central and northern Plains and high pressure along the East Coast will lead to breezy southerly winds both Monday and Tuesday afternoon with gusts of 30+ mph, hopefully providing a little relief from the heat! Wednesday - Friday: The core of the upper-level heat dome is forecast to set up over the Eastern U.S. through the middle to end of the week, placing eastern Iowa and northwest Illinois on the western fringe. This may allow a surface boundary to drop in from the NW leading to occasional chances for showers and thunderstorms. With the increased chance for occasional rain and slightly cooler 850mb temps, forecast highs are several degrees cooler for the mid/late week period, yet remain in the mid 80s to lower 90s. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1221 PM CDT Sat Jun 15 2024 Largely VFR conditions are expected through the TAF period. Our main focus for this set continues to be on a round of showers and storms expected late tonight. The latest high-resolution models show quite a bit of spread in the areal coverage of storms, so confidence is lower on the timing for any storms that impact local terminals. However, CID and DBQ remain the most likely terminals to see any storms, so continued the PROB30 groups for them, with brief MVFR/IFR conditions possible under the heaviest storms. As we get closer to the event, TEMPOs will likely be needed. Additionally, a 40 to 50 kt southwesterly low- level jet is expected tonight, so we have introduced LLWS to the TAFs to account for it. Gusty southerly winds are expected at times, especially during the daylight hours Sunday. && .CLIMATE... Issued at 315 AM CDT Sat Jun 15 2024 Record High Temperatures: June 16: KMLI: 98/1918 June 17: KBRL: 98/1944 KMLI: 98/1897 Record Warm Minimum Temperatures: June 17: KDBQ: 74/1921 KMLI: 78/2018 June 18: KDBQ: 74/1921 KMLI: 77/2018 June 19: KDBQ: 76/1931 KMLI: 78/1953 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Uttech LONG TERM...Uttech AVIATION...Schultz CLIMATE...Uttech/Schultz