Sunrise 5:54 AM   Sunset 7:56 PM Moonrise 3:37 AM   Moonset 2:50 PM

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FXUS63 KILX 031100 AFDILX

Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 600 AM CDT Fri May 3 2024

KEY MESSAGES

- Scattered showers and isolated thunderstorms diminish from the west during this morning, with isolated showers lingering near the Wabash river this afternoon. Cooler highs in the mid 70s today.

- Level 1 (marginal) risk of severe thunderstorms from mid Saturday afternoon into mid Sat evening over all but far eastern IL for gusty winds and hail.

- An active weather pattern re-establishes itself Monday through Thursday, with signals showing risk of strong to severe storms Tuesday and Wednesday especially during afternoon and evening hours.



DISCUSSION
Issued at 400 AM CDT Fri May 3 2024

Predawn surface map shows a cold front near I-55 with scattered showers along and east of the front and more numerous near the Indiana border. IR Satellite loop shows clouds over much of CWA while clearing skies just nw of Galesburg, Macomb and Quincy.
Temperatures ranged from mid to upper 50s west of the IL river, to the mid 60s from I-70 southeast.

Cold front to push east of IL/IN border by mid morning with scattered showers and isolated thunderstorms diminishing as cold front passes by. Though isolated showers still possible over the Wabash river valley this afternoon. Clouds to decrease over nw half of CWA during today, with mostly sunny skies by mid to late afternoon from I-55. Meanwhile skies stay cloudier over southeast part of CWA today. Winds turning NE behind the front at 5-15 mph so much lighter than past few days. Cooler highs today in the mid 70s, except upper 70s possible from highway 50 south in southeast IL.

Weak high pressure ~1018 mb over western IA drifts over WI and lower MI by sunset and ridging into central IL much of tonight and bringing fair weather. Some fog development noted east over parts of upper Wabash river valley of Indiana and gets close to Vermilion county/Danville area by sunrise Sat. Will keep fog out of forecast overnight and early Sat morning but will need to watch areas near the Indiana border. Lows overnight range from the lower 50s west of I-55 (upper 40s by Galesburg), to the lower 60s in southeast IL.

A short wave trof over the northern Rockies by Idaho and western MT to track eastward into the eastern plains by midday Saturday and push a cold front east through central IL late Sat afternoon and evening. Air mass gets unstable Sat afternoon with CAPES rising to 1000-1800 j/kg by mid to late Saturday afternoon while wind shear values are 15-25 kts. Isolated to scattered thunderstorms to develop during mid/late Sat afternoon and continue into Sat evening. SPC introduced a marginal risk of severe storms over all but far eastern/se IL from Watseka to Charleston to Mt Vernon west for gusty winds and hail from mid Sat afternoon through mid Sat evening. Highs Saturday around 80F to lower 80s with dewpoints back up in the low to mid 60s.

Convection chances diminish overnight Saturday night and Sunday morning and mainly 20-30% chance in southeast IL by Sunday morning.
A short wave moving ne into the Ozarks late Sunday to increase chances of showers and isolated thunderstorms in mainly southeast IL during Sunday afternoon with isolated showers possible late Sunday afternoon about as far north as I-72. Instability is weaker on Sunday so not in a threat of severe storms on Sun afternoon and evening. Highs Sunday in the lower 70s over central IL and 74-78 in southeast IL. The weak short wave trof lifts into southern/sw IL by dawn Monday and into the central Ohio river valley late Monday afternoon, and likely brings showers and chance of thunderstorms into southeast IL Monday while lower chances over northern CWA SPC day4 outlook for Mon/Mon night keeps severe risk area well west of IL over the central plains centered over central KS. Highs Mon in the mid to upper 70s.

Forecast models continue to show a large/strong mid/upper level trof evolving over the Rockies early next week, and ejecting strong low pressure from CO into ND Tue night and into the upper MS river valley Wed night. There will be periods of showers and thunderstorms over IL from this large storm system Tue through Thu with strong to severe storms possible Tue afternoon into Wed evening. SPC Day5 outlook has 15% risk of severe storms over IL Tue afternoon/evening. SPC Day5 outlook has 15% risk of severe storms se of IL on Wed/Wed night, but would not be surprise to see this expanded ne into parts of central and southeast IL Wed afternoon/evening as instability is decent on Tue and Wed with strong wind shear in place. Warm highs Tue/Wed in the lower 80s, except upper 70s nw of the IL river on Wed. Best chances of convection along with possible strong to severe storms shift se of CWA on Thu though still have low pops on Thu especially se half of CWA Cooler and less humid air arrives on Friday and next Saturday with seasonable highs in the upper 60s/lower 70s.

07

AVIATION
(For the 12z TAFs through 12z Saturday Morning)
Issued at 600 AM CDT Fri May 3 2024

A cold front was pushing through central IL early this morning, causing initially light/calm winds to go northwest/north later this morning and then northeast this afternoon near/under 10 kt. A narrow band of MVFR ceilings follows to front. These should scatter out by midday, with VFR high clouds to follow through 12z.

25

ILX WATCHES/WARNINGS/ADVISORIES
None.

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