Decatur, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

682
FXUS63 KILX 070545
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1145 PM CST Fri Mar 6 2026

.KEY MESSAGES...

- A few rounds of scattered thunderstorms are expected late this
  afternoon through Saturday morning, with the greatest coverage
  expected overnight (west of I-57) and east of I-57 later tonight
  into Saturday morning. Some of the storms could be strong to
  severe, especially from late this evening into early Saturday
  morning. There is a Slight Risk (level 2 of 5) of severe storms
  west of I-55, and a Marginal Risk (level 1 of 5) east of I-55.

- Unseasonably warm this afternoon, with highs reaching 75 to 80.
  Breezy southwest wind gusts of 25-35 mph are expected during the
  afternoon with a few higher gusts to 40 mph possible between the
  IL river and I-70 into early evening. More warm 70s likely
  Monday and Tuesday across central and southeast IL.

&&

.DISCUSSION...
Issued at 230 PM CST Fri Mar 6 2026

Strong SSW winds with gusts 25-35 mph (a few gusts to 40 mph)
along with some sunshine helping warm temperatures into the mid to
upper 70s se of the IL river. Peoria has reached 75 so far and
tied their record high of 75 set in 1956. Lincoln has reached 78
and 2 degrees shy of their record high of 80F. Springfield is 79F
and their record high is 83F. The last time it was this warm in
central IL was Oct 17th. More clouds and morning convection
keeping areas west of the IL river a bit cooler in the upper
60s/lower 70s. Rather muggy dewpoints in the upper 50s to mid 60s
accompanied this warmth. Radar mosaic shows lingering broken band
of convection nw of the IL river lifting northeast. A larger area
of convection was over northern MO moving ne toward west central
and nw IL. MUCAPES had increase to 1000-2000 j/kg se of the IL
river where more sunshine and heating of unstable air mass. Though
lifting mechanisms and boundary are more along and nw of the IL
river where MUCAPES are 500-1000 j/kg. Best effective bulk shear
values of 40-50kts are from Quincy to Bloomington nw though weak
inhibition/CAP remains over this area. There is a 35-45 kt sw 850
mb jet helping transport higher moisture into IL with PW values of
1.1-1.3 inches.

Expect higher chances of convection over the nw CWA rest of this
afternoon early this evening, while an isolated cell could still
pop up later this afternoon in eastern IL. The cold front over nw
Iowa into central KS and the latest CAMS have trended slower with
movement of cold front eastward toward far NW CWA by sunrise
Saturday and  through southeast IL by mid Saturday afternoon.
So have trended slower with convection chances to mainly overnight
and linger in southeast IL into Saturday afternoon. SPC day1
outlook has continued slight chance of severe storms west of I-51
overnight with marginal risk east with all severe wx parameters at
play with damaging winds the most likely. With slowly forecast of
cold front, SPC day2 marginal risk for large hail and damaging
winds was pushed back west a bit from Paris to Effingham line east
for Sat morning and early Sat afternoon. Mild lows overnight in
the upper 50s/lower 60s. Highs Saturday range from the upper 50s
and lower 60s over the IL river valley and upper 60s/lower 70s in
east central/se IL. Temps will fall about 10 degrees by supper
time Saturday behind the cold front as breezy SW winds turn west
to WNW behind cold front.

Colder lows Saturday night in the mid 30s, ranging from near 32F
at Galesburg to near 40F at Lawrenceville. This is still a bit
warmer than normal for early March lows. Weak high pressure around
1020 mb settles into the mid MS river valley Sunday with a fair
amount of sunshine and increase sw winds to breezy levels by
Sunday afternoon over central IL especially north of I-72. Highs
Sunday in the low to mid 60s, mildest over the IL river valley
west of I-55. Warmer 70s return to central and southeast IL on
Monday with ample sunshine and breezy sw winds. These warm temps
continue Tuesday and may be near record highs again on Monday and
Tuesday. We have a 20-30 chance of convection se of the IL river
Monday night, mainly after midnight.

Increasing chances of convection during Tue and Tue night as
strong cutoff 500 mb low moves into nw Mexico and near El Paso
Texas by Tue afternoon and storm system ejecting ne toward IL with
cold front approaching nw IL by sunset Tue. Cold front to push se
through IL Tue night and reach near the Ohio river by midday Wed.
This system will have more moisture to work with and a 1-2 inch
band of rain possible Tue-Wed with higher amounts possible south
of I-70 where river flooding currently going on on Embarras river
at Lawrenceville and Little Wabash river at Clay City. SPC Day5
outlook for Tue/Tue night has 15% risk of severe storms over SW
IL, as far northeast as Springfield. Feel this risk may expand
further ne over central IL Tue afternoon/evening with stronger
wind shear and dependent on amount of instability. Rain chances
diminish from nw to se later Wed and Wed evening as cooler air
arrives during Wed into Thu. Highs in the low to mid 50s over
central IL Wed and across southeast IL too on Thu.

A northern stream short wave/system passes by to our north on Thu
night and Friday with brunt of its pcpn north of central IL with
some warming ahead of it with highs in low to mid 60s next Friday.

07

&&

.AVIATION...  (For the 06z TAFs through 06z Saturday Night)
Issued at 1145 PM CST Fri Mar 6 2026

Another round of storms will be moving through the TAF sites
overnight. Based on HiRes models and current radar loops, this
looks very likely, so will opt for TEMPO group at all sites for
the first 4 hours of when storms should affect the sites. Then
will go with PROB30 groups as the main line should have moved
through the then isolated storms will be possible on the back side
into the morning hours. Cigs will drop into MVFR category behind
the boundary/front/precip during the morning hours but then
improve at SPI, DEC, CMI...while PIA and CMI remain higher MVFR in
hte afternoon. Southerly winds will be very windy through the
night becoming southwest later tonight/toward morning. Then expect
winds to become westerly late morning through afternoon and then
west to northwest afternoon into the evening hours. Very windy
until later this afternoon/evening.

Auten

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$