Area Forecast Discussion
Issued by NWS Central Illinois

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359
FXUS63 KILX 270513
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1213 AM CDT Sun May 27 2018

.UPDATE...
Issued at 856 PM CDT Sat May 26 2018

Spotty convection that impacted parts of the area late this
afternoon/early this evening is quickly weakening with the gradual
loss of diurnal instability. Unlike last night, there is not much
in the way of forcing to keep convection going as the boundary
layer stabilizes.

Temperatures overnight should cool toward the current surface dew
points, which are mainly in the mid-upper 60s. The models are not
suggesting much in the way of fog overnight, despite low expected
temp/dew point spreads, light winds, and minimal cloud cover.

Going forecast is in good shape with only minor hourly tweaks
needed at this time.

&&

.SHORT TERM...(This evening through Monday)
ISSUED AT 325 PM CDT Sat May 26 2018

LAPS CAPES have increased to 2400-4000 J/kg west of I-55 at mid
afternoon, and even above 4000 j/kg over northern MO, southeast IA
into far west central IL over the MS river valley. Wind shear is
weak though, so like a late summer time pattern, plus lacking
boundaries or short waves for lift over CWA. SPC day1 states the
strong instability over west central IL with MLCAPE values over
3000 J/kg and steep low-level lapse rates. Shear will be
relatively weak, promoting multicell storm structures with
occasional gusty/damaging winds and hail until sunset. A
thunderstorm recently developed just nw of Schuyler county and
another one east of Edgar county, drifting slowly southeast. Will
continue isolated convection through dusk mainly south of I-74.
Otherwise patchy fog could develop during overnight into early
Sunday morning especially south of I-72 where winds will be light
to calm tonight.

A strong 586-587 dm 500 mb subtropical ridge will build into
IA/MO/IL on Sunday and Monday bringing hot and humid weather with
near record highs in the low to mid 90s. Afternoon heat indices to
peak in the mid to upper 90s, with a few spots near 100F.
Kirksville, MO currently has a heat index of 100F. See climate
section for record highs today through Tuesday (May 26-29). Most
areas will be dry under this strong upper level ridge from Sunday
through Monday night. Continued isolated showers and thunderstorms
during mid/late Sunday afternoon in southeast IL where a weakness
in the upper level ridge will be along with a very unstable
airmass during Sunday afternoon with CAPEs rising back to
2500-4000 j/kg south of I-72. Isolated convection possible in
southeast early Sunday evening, otherwise another fair and muggy
night. Lows tonight and Sunday night will be close to dewpoints in
the upper 60s to near 70F.

.LONG TERM...(Monday night through Saturday)
ISSUED AT 325 PM CDT Sat May 26 2018

Tropical Storm Alberto just nw of Cuba with 40 mph winds, will
strengthen to a strong tropical storm as it tracks NNW and move
near Mobile, AL during Monday night. NHC then tracks remnants of
Alberto to near the TN/AL/MS border by late Tue night, and to near
Cincinnati, Ohio by 8 am Thu, and moving ne into the upper Ohio
river valley and eastern Great Lakes region during Thu. This
track is getting closer to southeast IL and ECMWF and GFS move it
further nw to west central or central IN by 7 pm Wed. Think
southeast IL will see a chance of showers and thunderstorms by Tue
afternoon. Highs Tue in the upper 80s and lower 90s, coolest in
southeast IL where more clouds and chances of convection. Chances
of convection then increase from south to north overnight Tue
night and Wed, with 50-60% pops in east central and southeast IL.
Highs Wed in the low to mid 80s due to more cloud cover and higher
chances of rain. Have 20-30% chance of showers and isolated
thunderstorms lingering Thu mainly east of the IL river, with
highs in the mid to upper 80s.

Extended models continue to build subtropical upper level ridge
west of IL late next week keeping very warm/humid summerlike
weather over the area. Convection chances appear low over CWA
Fri/Sat due to nearby upper level ridge. MEX and ECE guidance is
giving highs of 85-90 from Thu-Sat but may be conservative and
trending toward climatology especially on Fri/Sat.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1214 AM CDT Sun May 27 2018

VFR condtions should prevail through most of the 06 TAF valid
time. However, patchy MVFR fog is possible early this morning.
Otherwise, minimal cloud cover and light winds are anticipated.

&&

.CLIMATE...
Issued at 1155 AM CDT Sat May 26 2018

Here are Record Highs Today thru Tuesday in Central IL...

City          Today/May 26  Sun/May 27  Mon/May 28  Tue/May 29

Bloomington...  95/1911     95/1911     97/2012     97/1934
Charleston....  97/1911     97/1911     97/1911     96/1934
Danville......  99/1911     98/1911     97/1911     95/1942
Decatur.......  94/1985     96/1911     94/1991     96/1934
Effingham.....  94/1921     94/1972     94/2012     98/1895
Havana........  93/1967     93/1978     92/2006     95/2006
Jacksonville..  94/1953     92/2012     92/2006     95/1934
Lincoln.......  94/1926     94/1985     94/2006     96/1934
Mattoon.......  92/1972     92/1987     93/1991     92/1987
Minonk........  98/1911     96/1911     96/2012     98/1934
Paris.........  94/1911     96/1911     96/1911     95/1914
Peoria........  95/1911     94/1911     94/2006     99/1934
Robinson......  97/1911     97/1911     97/1911     96/2012
Rushville.....  94/1926     92/1978     92/1941     98/1934
Springfield...  95/1911     94/1911     94/2006     95/1934
Tuscola.......  98/1911     96/1911     97/1911     94/1991
Urbana........  95/1911     95/2012     94/1991     96/1934

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Bak
SHORT TERM...07
LONG TERM...07
AVIATION...Bak
CLIMATE...07



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