Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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782 FXUS63 KDVN 041128 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 528 AM CST Mon Nov 4 2024 .KEY MESSAGES... - Another round of moderate to heavy rainfall is expected tonight with the highest amounts along and east of the Mississippi River (1-2"+). - There is a Marginal Risk for a few severe storms tonight to the south of I-80. - Drier and more seasonable weather is forecast by the middle to end of the week with highs in the 50s. && .SHORT TERM /THROUGH TONIGHT/... Issued at 330 AM CST Mon Nov 4 2024 Early AM: The well advertised active pattern will continue into Tuesday with two more rounds of rain expected through this period. The first of which is currently impacting approximately the southeast half of the outlook area from near the Quad Cities and points to the east and south. The deeper convection with this early morning round will remain south of the area across central/northern Missouri into central Illinois. With PWATs between 1.20-1.50" still anticipate efficient rainfall on the northern edge of this batch of rain that has exhibited some pockets of heavier rain associated with convective elements embedded within the larger stratiform shield. However, the quick NE movement should hold amounts to 0.25-0.50" or less even in the eastern counties. Central to western sections will see little to no additional rainfall through the morning hours. We then look to catch a break in the widespread rain for much of the day as the area is void of a surface front or upper wave to initiate additional showers and storms. It will be very mild for this time of year with highs in the mid 60s to near 70 degrees! The deep upper trough across the Southwest U.S. is forecast to edge into the southern Plains later today, which will coincide with peak daytime heating and lead to a severe thunderstorm outbreak across portions of Oklahoma, Missouri, and Arkansas. This cluster of deep convection will quickly grow upscale with a reinvigorated low to mid-level jet (50-60+ kts at 850mb) directing the associated heavy stratiform portion of the cluster northward into portions of eastern Iowa and northwest Illinois by tonight. As mentioned for the past several days, the atmosphere will become anomalously moist with PWATs and IVT values peaking near the NAEFS and ECMWF ensemble 99th percentile to climatological max. Additional Heavy Rain Tonight: The enhanced IVT will act as a fire hose of moisture, advecting the narrow corridor of heavy rain and embedded storms up into portions of the outlook area tonight, most likely between 6 PM to midnight. Model ensemble consensus (NBM and HREF) is for the heaviest rain (2"+) to fall east and southeast of the Quad Cities, which aligns with the highest forecast IVT values. Fortunately, this part of the forecast area missed out on the heaviest rain with the initial round Saturday night into Sunday AM, making the soil conditions more receptive to absorbing this final round of significant moisture; the main concerns in the hardest hit locations are ponding of water in low-lying and poor drainage areas, along with quick rises on area creeks, streams, and tributary rivers. Thunderstorm Potential: A warm and very humid air mass (dewpoints in the lower 60s) will advect into the region from the south, out ahead of the approaching line of convection set to move into the southern forecast area by early tonight. SPC has maintained a Marginal Risk for severe storms to the south of I-80 with the primary threat damaging wind gusts and a low potential for a brief tornado. It will be a typical out of season high-shear low-CAPE environmental setup. With the convection coming in at night, surface-based CAPE will be meager. However, the highly sheared environment may compensate for the weak instability, providing a mechanism for QLCS organization and potential for localized strong wind gusts and possibly a brief spin up tornado. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Issued at 330 AM CST Mon Nov 4 2024 The surface low will continue to lift northeastward during the day Tuesday, so some lingering showers and perhaps an isolated thunderstorm will be possible during the morning hours. As the low deepens to the north across Wisconsin, we can expect gusty SW winds to develop, reaching 30-35+ mph during the afternoon. An area of high pressure will take control over the region Wednesday through Friday. The next decent chance for rain comes in Friday night into Saturday (40-60%). High temperatures Wednesday through Saturday will be in the upper 50s to near 60, with lows in 30s/40s. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 515 AM CST Mon Nov 4 2024 A humid air mass will lead to periods of MVFR/IFR ceilings early this morning as the rain gradually diminishes; there could be a brief window of VFR/MVFR ceilings for the afternoon with little precip across the region. Then heading into tonight, another round of widespread rain with embedded thunderstorms will move into eastern Iowa and northwest Illinois. The rain may become heavy at times, especially at BRL and MLI, and be accompanied by gusty winds and reduced visibilities to 1-3 SM. Low ceilings are expected through the overnight with IFR likely at CID and DBQ. && .CLIMATE... Issued at 225 PM CDT Sat Nov 2 2024 Record Daily Precipitation Amounts: November 4: KBRL: 1.61/1935 KDBQ: 1.61/2022 KMLI: 1.51/2022 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Uttech LONG TERM...Schultz/Uttech AVIATION...Uttech CLIMATE...Schultz