Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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084 FXUS63 KDVN 011726 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 1226 PM CDT Sat Jun 1 2024 .KEY MESSAGES... - Rainy first half of today before gradually diminishing into early evening. - Fog overnight and Sunday morning, which could be dense in some areas. - Active/Unsettled Sunday night through Tuesday night with several chances for showers and storms. Some potential for stronger storms Monday PM (conditional upon development) and Tuesday night ahead of a cold front. && .SHORT TERM /THROUGH SUNDAY/... Issued at 255 AM CDT Sat Jun 1 2024 A shortwave trough over Missouri with an attendant weak surface low reflection early this morning will translate generally eastward over the next 12-18 hours. 30-35+ kt low level jet and attendant moisture transport coupled with the upper forcing is resulting in widespread showers south of I-80 lifting northward. Overall, much of the area will see rain this morning. Isolated elevated convection can`t be totally ruled out, especially on the backside of the more widespread shower coverage where weak instability will reside attendant to better low level forcing. This afternoon as the mid/upper trough axis makes inroads the greater coverage of showers should migrate east of the Mississippi River. Most areas will see rain amounts of 0.5 inch or less, however with PWATs ramping up to 1.5 inches there is likely to be pockets of higher amounts to around an inch given slow cell motions and with any training of heavier showers. Given the cloud cover and rain, I have lowered highs in most areas today with highs generally from the mid/upper 60s east to the lower 70s. If enough sunshine can occur in the west as the rain tapers off this afternoon then some mid 70s would be possible. This evening, we may have a few lingering showers far east, while also can`t rule out a few showers or weak storms propagating into our northwest counties should they form along a weak boundary across north central to far northeast Iowa this afternoon. This potential will be dependent on just how warm it gets this afternoon to our west, more likely if highs get well into the mid to upper 70s. By late evening and overnight we should quiet down as a surface high pressure ridge builds in. The light winds and low level moisture aided by rain today will likely set the stage for fog potentially dense, especially near to west of the Mississippi River where the ridge axis is progged. Lows tonight are likely to drop into the 50s in most locations. The surface to mid level ridging will provide a short period of largely dry weather on Sunday. Highs will warm back to seasonable levels and generally in the upper 70s to lower 80s, and the humidity will be noticeable making for more of a summer-like feel. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Issued at 255 AM CDT Sat Jun 1 2024 A shortwave and cold front look to provide the focus for convection Sunday PM/evening across the Plains. This will advance into the region primarily overnight Sunday night into Monday morning, while likely weakening as it outpaces the better moisture transport and instability. Depending on the timing of the shortwave, we may need to keep an eye on Monday PM for any redevelopment and at least a low threat for a few strong storms. Soundings show a stronger deep layer shear potential likely augmented by the shortwave for some concerns over organized multicell storms with gusty winds should PM convection occur. Latest CSU machine learning probabilities for Monday do reach the equivalent of a Slight Risk for severe weather for wind across south/west portions of the service area. Largely south/southwest low level flow/ warm advection will foster above normal warmth, which coupled with increasing humidity will continue to make it feel summer- like heading into midweek. Toward mid to late next week the guidance continues to support a pattern change with an eventual deepening northern stream trough shifting into the eastern CONUS. An initial shortwave driving this pattern change will evolve eastward across the Northern Rockies and along the International border with ND/MN Tuesday into Wednesday. This will drive a cold front through the area Tuesday night into Wednesday bringing the potential for strong storms due the above normal warmth and moisture fostering greater instability. 00z ECMWF deterministic QPF has the look of a mature MCS developing to our northwest on Tuesday and diving E/SE into the instability across the region Tuesday night with wind potential given ramping deep layer shear, and this potential certainly bears watching over the next few days. Beyond, there`s quite the uncertainty in the deterministic and ensemble guidance on strength and position of the upper trough heading into late next week and next weekend. This owes to lower confidence on temperatures, as illustrated by NBM with Interquartile ranges as much as 10-15 degrees on highs over several days from Thursday through next weekend ranging from the lower 70s to the lower to mid 80s. Confidence in precipitation chances late week into next weekend is also low, modulated by the location of the upper trough. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1220 PM CDT Sat Jun 1 2024 A remarkable poor day of aviation weather is occurring today, on the first day of June! A persistent surface trof of low pressure, with upper level deformation zone rains continues to be positioned along the Mississippi River from this morning into the afternoon. This slow moving feature will continue to bring occasional rainfall through the afternoon, with low visibility of 1 to 4 miles, and cigs to 500 to 1000ft into mid afternoon. Some improvement is likely during the early evening, but with light winds and lots of low level moisture, especially in Iowa, we`re set to get LIFR/IFR fog tonight possibly with low cigs as well. The worst visibility and cig combination is expected between 08z and 12z Sunday, with improvement to VFR expected Sunday by mid morning. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...McClure LONG TERM...McClure AVIATION...Ervin