FXUS63 KILX 261939

AFDILX



Area Forecast Discussion...Updated

National Weather Service Lincoln IL

239 PM CDT Thu Jun 26 2025



.KEY MESSAGES...



- The heat wave will persist into the upcoming weekend for central

  and southeast IL. The highest heat index readings of 100 to 107

  degrees will occur this afternoon and early evening, but will

  remain in the upper 90s to around 100 degrees each afternoon

  Friday through Sunday. The Heat Advisory goes through 7 pm today

  across central IL, and extended until 7 pm Friday from Danville 

  to Charleston/Mattoon and Effingham southeast. 



- Rain chances will be minimal through tonight (20-30% areal

  coverage). Chance of showers and thunderstorms will be higher on

  Friday and Monday with frontal boundary moving through. 



&&



.DISCUSSION...

Issued at 235 PM CDT Thu Jun 26 2025



Continued the heat advisory until 7 pm today for central IL and

extended the heat advisory until 7 pm Friday from Danville to

Charleston/Mattoon to Effingham southeast. Heat indices should

peak from 100-107F through 7 pm with temps in the low to mid 90s

and dewpoints in the low to mid 70s. Heat indices are expected to

peak 100-105F in southeast IL on Friday afternoon and peak in the

90s over the remained of central IL. The high heat and humidity to

linger this weekend as heat indices peaking in the mid to upper

90s on Sat afternoon (highs near 90F) and 97-103F on Sunday

afternoon (highs in the lower 90s). 



Radar mosaic shows isolated convection over central IL from the 

IL river southeast to I-72 and southeast of I-70, lifting slowly 

northeast. Unstable tropical airmass with ML CAPES 2-3k j/kg and 

SB CAPES 3500-4200 j/kg. PW values of 1.6-1.8 inches. The main

synoptic frontal boundary was near the MN/IA border and southern

WI with 1009 mb low pressure near the MN/IA/SD border. SPC Day1

continues marginal risk of severe storms for damaging winds

northern half of CWA into early evening along with locally heavy

rainfall, similar to yesterday. As low pressure tracks to

northeast of Door County WI by 12Z/7 am Fri it will pull a cold

front se toward nw IL. This to bring chance of showers and

thunderstorms to the IL river valley late tonight into fri

morning. The front moves into northern cWA Fri night and then

lifts back into northern IL during Saturday. This to keep a chance

of convection around into this weekend, though chances will be

rather low over our area. More unstable tropical airmass lingers

over southeast IL Sat where higher pops will be. 



Sunday we will see tropical air mass lift further northward over

IL so temps and dewpoints along with associated Heat Indices to be

a bit higher. Have 30-40% chance of convection Sunday afternoon

and evening. Cold front to then push back se over IL on Monday

likely bringing showers and chance of thunderstorms. We are

currently not in an outlook for severe storms by SPC on Monday

afternoon/evening but will need to be watched with front moving

into an unstable air mass. Highs Monday in the mid to upper 80s

with Lawrenceville around 90F where heat indices peak in upper 90s

in far southeast IL Mon afternoon. After a chance of convection in

southeast IL Monday evening, expect dry conditions returning

overnight Monday night through Wed night as weak high pressure

settles eastward into IL during mid next week. More seasonable

temps and humidity levels for early July return middle of next

week with highs in the mid to upper 80s and lows in the mid to

upper 60s. 



07



&&



.ILX WATCHES/WARNINGS/ADVISORIES...

Heat Advisory until 7 PM CDT this evening for ILZ027>031-036>038-

040>045-047>055-061.



Heat Advisory until 7 PM CDT Friday for ILZ046-056-057-062-063-066>068-071>073.



&&



$$

