Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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038 FXUS63 KDVN 011746 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 1246 PM CDT Wed May 1 2024 .KEY MESSAGES... - Pattern remains active with periodic showers and storms through early next week. - Risk for heavy rain and a Marginal risk for severe weather Thursday into Thursday evening. && .SHORT TERM /THROUGH TONIGHT/... Issued at 318 AM CDT Wed May 1 2024 Cold front was nearing the Mississippi River at 2 AM, and will exit eastern areas prior to sunrise. Northwest winds post- frontal will remain gusty through midday/early afternoon, especially north of I-80 where gusts to 30 mph possible before winds diminish mid to late PM as high pressure builds in. Anticipate ample solar insolation today mixed with some mid/high cloudiness, especially early on and then again later today. The dry advection and sunshine should get highs back into the upper 60s to mid 70s, which is near to a little above average for the start of May. We may see some returns this afternoon on the radar as elevated warm advection commences, but dry low levels with the surface high should preclude any precipitation from reaching the ground. Otherwise, tonight 850 hPa moisture advection and transport will ramp up ahead of a mid level shortwave ejecting from the Central Plains. This will lead to a burgeoning of showers across the area, with a few to scattered storms overnight on the nose of 40-50 kt LLJ while 0-4km CAPE increases to upwards of around 500 j/kg and 850 hPa - 500 hPa theta-e lapse rates go negative. A little CAPE exists in the growth zone while mid level lapse rates steepen over 7-8 c/km, so can`t totally rule out small hail being possible with the strongest convection. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 318 AM CDT Wed May 1 2024 Thursday will feature rounds of showers and storms between the lifting warm front during the day and cold front Thursday evening/night. PWATs increase to near 1.5 inches will support heavy rain potential with any repetitive convection, and the 00z HREF layer probability matched mean QPF for 24 hrs ending 00z Friday supports this idea indicating swaths of 1-2+ inches. This could lead to localized flooding concerns particularly if it occurs in areas that have seen recent days of rainfall and where soil moisture is above average, particularly across portions of the south and eastern service area. Deep layer shear is more than sufficient to support organized convection, however the uncertainty lies with the extent of destabilization due to the clouds and precipitation. If some areas were to see a lull in precipitation and some breaks owing to heating, then we could see the potential for a few stronger storms with gusty winds and marginal hail. Would also have to keep an eye on the warm frontal position as where that resides a low-end tornado risk could develop should sufficient low level instability occur. Friday, NBM continues to linger precipitation chances 30-50% across the area however, much of the deterministic guidance is progressive with the front and would allow for more subsidence and drier conditions. As a result of collaboration with neighbors we`ve lowered PoPs Friday/Friday night toward a drier scenario. Beyond, the pattern is set to stay active through early next week, as initially a couple of shortwaves eject across the Midwest over the weekend ahead of another deep western trough that looks to eject out early next week. This will result in continued periodic bouts of showers and storms. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1233 PM CDT Wed May 1 2024 Broken mid to high clouds are moving westward across KCID and KDBQ to start the period as high pressure builds into the area. Northerly winds will continue to gusts up to 30 knots through the afternoon before diminishing this evening. Widespread rain showers and potentially embedded thunderstorms are forecast to develop after 00 UTC near in a stalled frontal boundary in northern Missouri and slowly spread north and eastward overnight. This will cause initial VFR conditions to lower to MVFR as rain spreads into the area after 06 UTC. Rain will slowly come to an end from west to east after 12 UTC on Thursday. Confidence is low on the exact timing of thunderstorms so placed a prob30 group in the TAFs for now. Gusty east winds are forecast to develop after 12 UTC and continue through the day. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...McClure LONG TERM...McClure AVIATION...Cousins