Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Lincoln Illinois
1257 PM CDT sun Apr 26 2015

Update...
issued at 1041 am CDT sun Apr 26 2015
high pressure building back into the region with a surface ridge axis
just to the west. North/northeasterly winds continue through the
day, getting a little gusty later this afternoon with a little bit
of mixing. Models hinting at a little bit of moisture between
5000-8000 feet or so. Cumulus rule not particularly strong under the
ridge and mixing may inhibit a lot of cumulus...but still possible to
see a few later this afternoon. Otherwise quiet, and no
significant updates anticipated at this time.

&&

Short term...(today)
issued at 330 am CDT sun Apr 26 2015

Low clouds continue to gradually work their way south through
central and east central Illinois early this morning as drier air
advects from the northeast. Mostly cloudy conditions will linger
in southeast Illinois from daybreak until mid-morning. Plenty of low
level mixing in the lower atmosphere late this morning through the
afternoon will result in northeast winds gusting close to 20 miles per hour
especially east of the I-55 corridor. Despite plenty of sunshine
by afternoon...highs today will mainly be around 60 degrees due
to the deep low level northeast flow.

Long term...(tonight through saturday)
issued at 330 am CDT sun Apr 26 2015

Fairly quiet weather on tap across the forecast area much of the
week. Persistent northeast flow to keep dry conditions in place...
with high temperatures rising a couple degrees each day until we
finally get near or just above normal by the end of the work week.

Upper low currently in the process of closing off over western
Arizona...and this will be tracking across the southern U.S. Over
the next few days. All of the models keep the associated moisture
south of the Ohio Valley. A shortwave will also be tracking along
the Canadian border...and as previous model runs indicated, a small
closed low will pinch off in the southern part of the wave. The
European model (ecmwf) and Canadian models have this small low dropping across
Minnesota and Iowa Tuesday night...while the tail end of the NAM
brings this into northern Illinois and the GFS progresses the wave
well east before the low can form. Net result of all of this is for
dry conditions middle week.

As we get later in the week...upper ridging will build northeast
across the plains into Manitoba...while general broad troughing
continues across the eastern U.S. This ridge flattens by Friday as
the northern stream becomes more active along the Canadian border.
Both the GFS and European model (ecmwf) bring a surface boundary through the area
Friday night and Saturday...with some light precipitation. The
solutions begin to diverge by evening...as the GFS brings a stronger
upper wave and surface front through Saturday night with showers and
thunderstorms...although the European model (ecmwf) does hint at potential mesoscale convective system
activity as well. With the more divergent solutions...have kept the
late weekend forecast dry for now.

&&

Aviation...(for the 18z tafs through 18z Monday afternoon)
issued at 1254 PM CDT sun Apr 26 2015
VFR and breezy north-northeast winds through the afternoon, becoming more
light and variable in the overnight. Little expected in the way of
ceilings and diurnal mixing today already plummeting the dewpoints
considerably. Will watch closely for the xover values this
afternoon, as radiational cooling will drop temperatures tonight
efficiently. So far, not looking like a good fog set up, but will
continue to watch the boundary layer relative humidity.

&&

Ilx watches/warnings/advisories...
none.
&&

$$

Update...hjs
short term...Miller
long term...geelhart
aviation...hjs

National Weather Service Glossary of Abbreviations