Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kilx 160816 

Area forecast discussion
National Weather Service Lincoln Illinois
316 am CDT Mon Sep 16 2019

issued at 230 am CDT Mon Sep 16 2019

Hot and humid conditions are expected into the middle of the week,
but otherwise fair weather as high pressure builds across the
region. Temperatures will average well above normal over the next
several days, with afternoon highs in the upper 80s to around 90.

Short term...(today and tonight)
issued at 230 am CDT Mon Sep 16 2019

An expansive area of high pressure is in place across the Midwest
and Great Lakes. Some patchy fog is occurring early this morning
within the light flow and still humid conditions, but most of the
day should be sunny and warm. Temperatures will top out in the mid
to upper 80s this afternoon with a few 90s possible south of
I-70. Quiet weather continues tonight with overnight lows in the
mid 60s.


Long term...(tuesday through sunday)
issued at 230 am CDT Mon Sep 16 2019

A strong upper ridge will be centered along the Mississippi River
valley or Great Lakes region through the latter half of the week,
providing primarily dry weather along with hot and humid
conditions. The pattern begins to break down over the weekend
allowing more unsettled weather to return to central Illinois.

On Tuesday, a strong shortwave will be in place over the Great
Basin and is progged to lift to the Canadian prairies by
Thursday. Modest buckling of the upper ridge will occur over the
Midwest in response to this wave. At the surface, low pressure
will lift across Hudson Bay Wednesday night and Thursday while a
front trails back across portions of the upper Midwest becoming
more east/west oriented across Iowa and Nebraska. This will serve as the
focus for some showers and thunderstorms Wednesday night which
models continue to indicate could build towards central Illinois
Thursday. Outside of the possibility of a morning mesoscale convective system reaching the
local area early Thursday, forcing continues to appear quite weak
during this time frame and soundings show some weakness in the
mid level lapse rates that could keep the area capped from deep
convection Thursday afternoon and evening as well as Friday.
Continue to lean towards the drier European model (ecmwf) and Gem solutions during
this time frame and only pops are generally limited to the
Illinois River valley and areas west late in the week.

Better chances for more widespread precip appears possible over
the weekend as another stronger wave lifts across the Great
Plains while the upper ridge finally gets shunted farther east
across the Appalachians. Attendant cold front is progged to push
across the Midwest over the weekend resulting in showers and
thunderstorms for central Illinois. Temperatures should moderate
closer to if not slightly below seasonal norms behind the front
late in the weekend into early next week.


Aviation...(for the 06z tafs through 06z Monday night)
issued at 1125 PM CDT sun Sep 15 2019

Expect areas of fog developing overnight as a weak surface front
slowly slips southward through the area combined with high
pressure bringing light and variable winds. Very moist conditions
remain, especially north of I-72 where widespread rain fell
Sunday. Questions remain regarding visibilities and ceilings with
fog and/or stratus development, however have incorporated IFR
conditions from 10z-14z at kpia, kbmi, kcmi but only MVFR at kspi
and kdec where it appears likelihood and intensity of fog is
lower. Otherwise, expect VFR conditions with a band of cloud
cover around 5000 ft above ground level slowly moving southward overnight ahead
of the cold front. Scattered diurnal cumulus will re-develop late
Monday morning as fog dissipates. Winds light and variable then
becoming north-NE up to 7 kts after 15z.


Ilx watches/warnings/advisories...


National Weather Service Glossary of Abbreviations