Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
861 FXUS63 KDVN 261737 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 1237 PM CDT Fri Apr 26 2024 .KEY MESSAGES... - Active pattern through the weekend with rounds of showers/storms with areas of heavy rainfall (1-3+ inches). - Severe storm risk exists through the weekend, but there remains uncertainty as prior rounds of convection may impact magnitude/timing/location of any severe weather threat. && .SHORT TERM /THROUGH TONIGHT/... Issued at 308 AM CDT Fri Apr 26 2024 Active convection was occurring across Nebraska early this morning ahead of a lifting wave from Colorado. This wave will eject northeastward into the Upper Midwest over the next 24+ hours taking on a negative tilt, while at the surface a warm front will eventually lift northward through the region later tonight. Until doing so, we`ll see rounds of showers develop/lift northward across the region today into tonight in the low level warm advection, with one main round evolving from south to north 12z-20z then a decrease before more scattered activity tonight between the warm front and nocturnal LLJ which could result in a few stronger storms tonight. Proxy forecast soundings show increasing surface inhibition (CIN) with fairly tall, skinny CAPE profiles and so marginal severe hail would appear to be the primary threat. However, remnant surface based convection that is anticipated to develop to our west this afternoon could move and/or further develop into portions of the cwa mainly west/south later this evening/tonight with aid of glancing ascent from the lifting shortwave. This activity tonight may also be accompanied by a marginally severe gusty wind threat, as negative 0-4km theta-e lapse rates develop post-warm front. Highs today will show a wide range, from the lower to mid 50s north, to the mid 60s far south as the warm approaches with winds staying brisk/gusty 20-35 mph. Lows tonight will be steady to rising with the passage of the warm front. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 308 AM CDT Fri Apr 26 2024 Saturday, a brief lull in convection is anticipated as weak amplification of mid level ridging occurs in the wake of the departing shortwave and ahead of the downstream upper low over the Four Corners region. This bout of weak subsidence may allow for at least partial sunshine. This combined with southerly winds in the warm sector will push highs well into the 70s and lower 80s. Dew points climbing into the 60s will make for a more humid feel. The combination will yield MUCAPE in excess of 1500+ j/kg, while deep layer shear will be in excess of 35-40 kts. This would support the potential for organized severe convection, but the challenge is with the trigger which is initially lacking and barring no boundaries for PM development we may be waiting until evening for more robust and better storm coverage to occur with the increasing nocturnal LLJ. This would bring a mostly large hail and damaging wind threat. Sunday, the upper low will lift out and take a similar path to the previous shortwave from Colorado into the Upper Midwest by Monday morning. We`ll see widespread showers and storms occur Sunday into Sunday night with the warm, moist advection and increasing synoptic scale lift then followed by the cold frontal passage Sunday night into Monday AM. The widespread precipitation and cloud cover brings about uncertainty as to the severe weather potential and magnitude/location, etc. Overall, we have 2 surges of PWATs of around 1.5 inches the first today into this evening and the second Saturday night through Sunday. Those would be the periods favored for locally heavy rainfall concerns. Between both events many areas will see widespread 1 inch or more (Friday through Sunday) with areas/swaths of 2-4+ inches where rounds of convection occur that will bring a risk of isolated flash flooding. In the wake of the cold front, the start of next week looks to turn quieter and drier. However, there`s signs that an active pattern will return mid to late next week with the flow becoming semi-zonal shuttling impulses across the Midwest from the Pacific along a meandering mid level baroclinic zone. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1227 PM CDT Fri Apr 26 2024 Active weather today into tonight will lead to poor aviation conditions with periods of showers and storms, accompanied by MVFR/IFR ceilings and visibilities. The best chances for occasional embedded thunder are at MLI and BRL, with lower instability anticipated further to the north. Another round of scattered showers and isolated storms is forecast to develop this evening into early tonight and shift SW to NE through the region. Additionally, gusty SE to SSW winds will continue through tonight. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...McClure LONG TERM...McClure AVIATION...Uttech