![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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
48
49
50
249 FXUS63 KILX 150143 AFDILX Area Forecast Discussion...Updated National Weather Service Lincoln IL 843 PM CDT Wed Aug 14 2024 .KEY MESSAGES... - Two periods of thunderstorms are expected Thursday, one early in the morning and the other in the mid to late evening. Of these, the latter storms have the highest chances for severe weather, with damaging winds the greatest concern. - Locally heavy rain will accompany the showers and storms, though probabilities of a widespread 1+" of rain are fairly low. - After Friday, an extended period of quiet weather is expected through the first half of next week. && .UPDATE... Issued at 841 PM CDT Wed Aug 14 2024 This evening, low pressure is located over SD/NE with a broad corridor of warm air advection inching east across portions of the mid Mississippi Valley. A few showers and storms are noted near the Mississippi River, but 00Z KILX sounding showed dry conditions up to around 600mb with very weak and capped instability. As such, this convection forming in the WAA to our west should struggle as it moves into central Illinois late this evening. Meanwhile, a more organized line of storms currently over KS/NE will spread east overnight on a veering LLJ. This will advect weak instability into portions of the lower Illinois River Valley late tonight into Thursday morning supporting a decaying line of showers and storms into the local area. Deubelbeiss && .SHORT TERM... (Through Late Thursday Night) Issued at 302 PM CDT Wed Aug 14 2024 Latest radar mosaics show scattered thunderstorms across central Missouri into southeast Iowa, in the wake of the earlier MCS which continues to sink southeast and weaken. Latest HRRR has latched onto this activity and sneaks it into west central Illinois by 5-6 pm, before weakening. However, orientation of the instability axis would suggest a southeast motion as well. Will keep some 20% PoP`s going through late afternoon from about Peoria-Springfield westward. Main focus remains with a couple periods of thunderstorm activity late tonight into Thursday night. Morning high-res models continue to suggest linear convective initiation across Nebraska and Kansas very late in the afternoon, with upscale growth into an MCS during the evening. While the main line still looks to arrive in our forecast area after 3 am, a few showers may develop ahead of it on the fringe of the upper jet spreading toward the Mississippi River. By midday, what`s left of the line should be close to the I-70 corridor. Severe potential during this period appears low. Main period of concern for severe weather still appears to be in the evening. A low level jet will help with renewed storm development to our west early in the evening. Some variety noted on the CAM`s with the extent of this development, though most are pointing toward a period from about 9 pm Thursday to around 2 am Friday with the highest potential. Damaging winds appear to be the main focus, though some hail can`t be ruled out if the storms remain more discrete as they enter the area. In terms of the heavy rain potential, there remains some fluctuation with the heavier QPF axis, though precipitable water values peak toward sunrise Thursday. HREF probabilities of 6-hour rainfall amounts over 1 inch of rain peak around 30% west of Springfield with the early morning activity, and near Peoria (40-50% chance) with the evening storms. Temperature-wise, assuming clouds break up enough by afternoon, highs should be a few degrees warmer than today, mainly in the mid 80s. However, with a substantial increase in dew points (mid 70s), heat index values in the low-mid 90s are expected west of Peoria and Springfield. Geelhart .LONG TERM... (Friday through Next Wednesday) Issued at 302 PM CDT Wed Aug 14 2024 The longer range pattern will be dominated by an amplifying upper ridge along the east slopes of the Rockies, which will persist into the middle of next week. An upper low will slide across the Great Lakes through the weekend, as a longer wave upper trough develops. These two features will keep a northwest flow across Illinois, with temperatures running a few degrees below normal and no significant surges of low level moisture to add to the humidity. Some wraparound showers can`t be ruled out on Friday and Saturday in the cyclonic flow around the low, though better chances appear closer to the Great Lakes and thus our forecast will be kept dry for now. After that, surface high pressure will dominate the Midwest with continued dry conditions. Geelhart && .AVIATION... (For the 00z TAFs through 00z Thursday Evening) Issued at 623 PM CDT Wed Aug 14 2024 Thunderstorms are expected to develop and expand in coverage over MO/IA late this evening and eventually move across central Illinois late tonight into Thursday morning, likely in a weakening phase. MVFR or IFR ceilings may accompany the precip and linger for a few hours Thursday morning. SE winds tonight into Thursday morning will turn southerly Thursday afternoon and will gust to around 20kt as conditions return to VFR. Deubelbeiss && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$