textproduct: Central Illinois

KEY MESSAGES

- Areas of dense fog are ongoing this morning. Use caution if traveling as visibility may change rapidly and often.

- Unseasonably warm air (20-25 degrees above normal) on deck for this week, peaking Wednesday and Thursday with mid-to-upper 60s temperatures. Gusty southwest winds on Tuesday & Wednesday will accompany this warmup. There is a 50-80% chance for wind gusts exceeding 30 mph.

- A conditional threat for severe weather remains possible but not particularly likely in the Wednesday-Thursday timeframe.

DISCUSSION

Issued at 226 AM CST Mon Feb 16 2026

There are areas of dense fog across central and southeastern IL this morning. Expectations were that the fog would clear out in the northwestern counties as some high clouds moved in and winds began to increase some, but it is hanging on real tight this morning. There is a Dense Fog Advisory out for eastern and southeastern IL that will expire at 14z. The rest of the forecast area affected by the fog is being message with a Special Weather Statement. The fog should dissipate as the sun rises this morning. If traveling, be prepared for rapidly changing visibilities (ranging from no vis to clear field of view) from the patchy nature of the dense fog.

Above normal temperatures have settled in for the work week. Highs in the upper 50s to mid 60s, and lows in the mid 30s to mid 40s (into the mid 50s on Tuesday night as an exception) are forecast through Thursday. The warmest day being Wednesday with the NBM having a 60-80% chance of temperatures exceeding 65 degrees that afternoon.

Today through Wednesday, while being warm, will also be quite windy, with forecast wind gusts of 20-30 mph. Pressure gradient will be tightening ahead of a series of low pressure systems this week. The strongest wind gusts are expected from tomorrow afternoon into Wednesday afternoon with NBM probabilities of 50-80% chance for wind gusts exceeding 30 mph.

There is a series of low pressure systems forecast to travel across the US this week. The first arriving tomorrow night into Wednesday morning is the next chance (20-50%) for some rain, particularly north of I-70, as a low passes off to the north of IL. The GFS and Euro models are showing very minimal precipitation coverage with this round. Thunderstorms look unlikely as the cold front moves through. Rainfall amounts look to be pretty minimal (< 0.1 inch) as of this forecast cycle.

The second system looks hold a bit more impact and is expected Thursday into Friday. This system will bring rain and thunderstorm chances (40-60%) to central and southeastern IL. QPF of up to three tenths of an inch. Thursday afternoon eastern IL forecast soundings are showing a couple hundred J/kg of MUCAPE and 20-30 knots of bulk wind shear. This is stunted although by a cap of up to -100 J/kg of CIN. There is better environmental support for severe weather south of I-70 compared to north of I-70, so that would be the area to watch for any potential to develop. Machine learning is hinting at the possibility of severe weather with this system (especially in southeastern IL), but confidence is still low in any severe weather occuring as of now. We will continue to monitor trends as we approach Thursday.

A cool down to more seasonable temperatures behind the series of systems and frontal boundaries that will pass this week. Highs starting Friday are in the mid 30s to mid 40s and lows in the 20s. Sunday potentially be the coolest with highs near freezing and lows in the teens Sunday night.

Copple

AVIATION

(For the 06z TAFs through 06z Monday Night) Issued at 1049 PM CST Sun Feb 15 2026

Dense fog has developed over eastern and southeast Illinois late tonight with patchy fog reported as far west as the IL River. The lowest visibility should stay just outside of most TAF locations, but IFR to occasionally LIFR conditions would be most favorable at KCMI and KDEC. Further west, a tightening pressure gradient/increasing winds overnight should minimize widespread dense fog. Conditions will improve by mid to late morning as southwest winds become breezy. Winds subside and back to the south heading into Monday evening.

NMA

ILX WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until 9 AM CST this morning for ILZ044>046- 054>057-061>063-066>068-071>073.