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Area forecast discussion 
National Weather Service Lincoln Illinois
1112 PM CDT Wednesday may 27 2015

issued at 830 PM CDT Wednesday may 27 2015

00z surface map indicating the weak cool front that edged
southeast across the area during the day has pushed to the
I-70 corridor early this evening. Showers have been trying
to develop along the boundary late this afternoon but
instability has been weak thanks to the cloud cover and
shower activity that pushed across parts of southeast Illinois
this morning. Will continue to carry slight chances for
that area for the next several hours before quiet weather
holds across the forecast area overnight and through the day
on Thursday. Will carry just slight chances over the far
southern areas for tomorrow afternoon but it appears that
most of the forecast area should be rain-free Thursday.
Updated forecast should be out by 845 PM.


Short term...(tonight)
issued at 247 PM CDT Wednesday may 27 2015

19z/2pm surface analysis shows weak cold front extending from
Danville to near Saint Louis. Band of enhanced cumulus continues to
accompany the front...however only a few isolated showers are noted
on radar near the Indiana border across Edgar County. Latest
mesoanalysis indicates only weak instability with sbcapes in the 500
to 1500j/kg range ahead of the front. In addition...0-6km bulk
shear remains very weak at less than 20kt. Due to these unfavorable
conditions...think only widely scattered showers and thunderstorms
will develop along the front this afternoon and evening. Boundary
will sag southward to near I-70 by have included a 20 pop
across the southeast kilx County Warning Area through mid-evening. After
that...expect dry conditions for the remainder of the night. A
slightly cooler/drier airmass will gradually trickle in from the
west...allowing overnight lows to drop into the upper 50s and lower

Long term...(thursday through wednesday)
issued at 247 PM CDT Wednesday may 27 2015

Upper air and moisture channel satellite data depicts upper wave
over Illinois moving east which will allow slightly drier air into region
through Thursday.

System now in the northern rockies then moves into the plains, to
drag a alow moving frontal toward area by Thursday night. Moisture
advection ahead of the front brings increased chance of storms
Thursday night and into Friday. Instability a bit limited but with
front to west, chance of marginal severe on Friday with approaching

Most significant rain Friday night into early Saturday as the front
prognosticated to cross into area. Models are pretty much similar on
expected frontal timing.

Front moves through by Saturday, but with weak upper trough forming
over middle MS valley, the moisture and showers are slow to clear and
so chance probability of precipitation over area into Sunday and southeast early Monday.

Rainfall will for most part by a prolonged period, with slow moving
front and so the central and southeast areas will have most
significant rainfall, but with only minor expected flooding

Early next week then to be slightly cooler and drier till midweek
with next system.


Aviation...(for the 06z tafs through 06z Thursday night)
issued at 1100 PM CDT Wednesday may 27 2015

VFR conditions will prevail through this forecast period. Weak high
pressure will drift across the area overnight bringing a mostly
clear sky and light winds. That should continue into the morning
hours of Thursday before winds turn into the southeast with
speeds of 10 to 15 kts by afternoon. Scattered to broken cirrus
and some middle level clouds are expected later tomorrow evening
as our next weather system affects areas to our west late Thursday
night into Friday morning with showers and thunderstorms.


Ilx watches/warnings/advisories...


short term...Barnes
long term...goetsch

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