Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

000 
FXUS63 KILX 280443
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1143 PM CDT Sun May 27 2018

.UPDATE...
Issued at 921 PM CDT Sun May 27 2018

Quieter weather has returned to central and southeast Illinois
this evening. Scattered showers and storms impacted parts of the
area during the afternoon and early evening hours, but have faded
with the loss of diurnal heating. Elevated instability lingers
across the area, but there is not much in the way of a trigger,
aside from outflow boundaries from earlier storms, to initiate
additional showers/storms for the rest of the night. Not
surprisingly, most model guidance is dry overnight. Can't rule out
an additional shower or storm, but confidence in when/where this
would occur is too low to include in forecast.

Going forecast for overnight is in good shape overall. Only minor
tweaks to hourly trends are needed at this time.

&&

.SHORT TERM...(This evening through Monday night)
ISSUED AT 310 PM CDT Sun May 27 2018

Isolated to scattered strong to locally severe thunderstorms have
developed along and southeast of I-55 at mid afternoon and
drifting slowly sse at 5-15 mph. The tropical heat and humidity
gave a very unstable airmass with LAPS CAPES of 2000-5000 j/kg,
highest values south of I-74 and north of I-70. Temps rose into
the low to mid 90s by mid afternoon. Heat indices peaked from mid
to upper 90s and few spots around 100F. But some cooling at some
sites from thunderstorms. Dewpoints also dropping especially ne
CWA where 55-65F dewpoints from I-74 ne, while very moist
dewpoints in the upper 60s/lower 70s from Lincoln sw. A strong 587
dm 500 mb subtropical ridge extended from west Texas into sw IA
was giving the heat wave to central and southeast IL today and
will continue Monday/Memorial Day.

Diurnally driven isolated to scattered convection will dissipate
by sunset over central and southeast CWA with nighttime period
tonight being dry. Some patchy fog possible overnight in southeast
IL. Lows tonight in the upper 60s to around 70F. Another hot day
on Monday with highs in the low to mid 90s and a few cities will
again reach near records. Please refer to climate section for
record highs today through Tuesday. Going with a dry forecast on
Monday with strong upper level ridge nearby and also getting
subsidence from subtropical storm Albert that moves into the FL
panhandle by Monday morning and into south-central AL by sunset
Monday. An isolated thunderstorm could develop south of highway 50
during mid to late Monday afternoon. Heat indices will again peak
in the mid to upper 90s with a few cites near 100F. Lows Monday
night around 70F. 

.LONG TERM...(Tuesday through Sunday) 
ISSUED AT 310 PM CDT Sun May 27 2018

On Tue will see northern fringe of Alberto's rain bands moving
into areas from I-72 south during Tue afternoon where 20-30% pops
of showers and thunderstorms. Highs Tue in the lower 90s central
IL and upper 80s in southeast IL where more cloud cover and higher
rain chances. Heat indices Tue afternoon are in the low to mid
90s. 

The remnants of Alberto to lift toward sw IN by sunrise Wed and
move northward over western Indiana during Wed, before curving ne
into central lower MI by sunrise Thu. 12Z forecast models have 
been trending further west with this tropical system and looks 
like central and eastern IL will see a better chance of beneficial 
rains. Chances of showers and thunderstorms will increase from 
north to south during Tue night and have likely to categorical 
pops in eastern IL overnight Tue night into Wed. Pops then 
decrease to chance in eastern IL on Wed evening. Expect 1-2 inches
of rain possible in eastern IL from Tue night through Wed 
evening. Much less amounts in western IL where quarter to half 
inch amounts possible. Wed to be the coolest day due to Alberto 
being nearby with highs in the lower 80s, coolest in eastern IL 
where around 80F, and near 85F in west central IL. 

Forecast models continue to linger chances of showers and isolated
thunderstorms Thu and Thu especially east of the IL river with a
lingering upper level trof over the area. Temps warm back up to
85-90F on Thu with return of partly to mostly sunny skies on Thu.
A sharp upper level ridge builds west of IL late this week with 
upper level trof east, though models differ with placement and 
intensity of this trof. GFS model is stronger with cutoff low 
closer to IL over Ohio river valley on Sat while favored Ecmwf 
and GEM models have upper level low further east over mid Atlantic
states. Have slight chance of showers/thunderstorms east of I-57 
on Friday, then dry. Highs Fri in the upper 80s to around 90F, 
then mid to upper 80s Sat and low to mid 80s on Sunday. 

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1140 PM CDT Sun May 27 2018

VFR aviation weather conditions expected across the central
Illinois terminals through most of the 06Z TAF valid time.
Isolated showers/storms possible again Monday afternoon/evening,
but confidence in explicit timing & coverage is too low to 
include in the terminals at this time. Overall, minimal cloud 
cover and light winds are expected through the period.

&&

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

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

City.......... Sun/May 27 Mon/May 28  Tue/May 29 

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

&&

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

$$

UPDATE...Bak

National Weather Service Glossary of Abbreviations