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Area forecast discussion 
National Weather Service Lincoln Illinois
251 am CDT Thursday Jul 30 2015

Short term...(today)
issued at 251 am CDT Thursday Jul 30 2015

A spectacular Summer day is on tap for central and southeast
Illinois today. High pressure at the surface and neutral to weakly
cyclonic flow aloft will help ensure this fact. The airmass is much
drier than we have seen lately so cloud cover will be minimal, and
humidity will be low. While most locations are likely to top out in
the upper 80s for daytime highs, low dew point temperatures and a
westerly breeze will help keep conditions comfortable.


Long term...(tonight through wednesday)
issued at 251 am CDT Thursday Jul 30 2015

Evolution of the upper pattern into the West Ridge/east trough
configuration is the large upper low spins just south
of Hudson Bay. Not much change through early next week from recent
model the ridge builds across The Rockies and the low
wobbles over the same general area. Getting closer to middle week...the
GFS tries to build the ridge slowly eastward into the plains...while
the European model (ecmwf) breaks it down. Both patterns would result in below normal
temperatures returning by Tuesday...although the European model (ecmwf) would favor
much cooler conditions than the GFS. Right now...will go a little on
the warmer side...but highs in the 80 degree range midweek would
still be a few degrees below normal.

Periodic impulses rotating around the upper low and down the upper
side of the ridge will be the main challenge for the next few days.
The first arrives on Friday...and the second on Sunday. Have
introduced some isolated thunderstorms Friday afternoon and evening
with the first boundary. Latest Storm Prediction Center day2 outlook indicates a few of
the storms may be strong to locally convective available potential energy rise over 2500
j/kg and some 0-6km shear of 30-35 knots occurs along the front. Not
looking for anything widespread with the rain as forecast soundings
do not stay moist for any decent period of time. Second wave late
Saturday night and Sunday is a little more pronounced...and much of
the precipitation is favored just to our north...although the GFS
and European model (ecmwf) do bring a bit more of a southward surge. These trends
were largely present in the previous forecast...and only needed some
minor tweaks.

Convective activity next week is more uncertain due to the potential
breakdown of the western ridge. Both agree the next wave should be
coming through Monday night...but the European model (ecmwf) hangs it up as the ridge
breaks down and another impulse arrives in the southern stream. That
solution would favor more extended rainy periods from Tuesday
through Wednesday night...while the GFS exhibits more of an mesoscale convective system
pattern for the middle of the week. With the wide variety...will
keep rain chances more in the 30-40% range for now with no
significant confidence in either solution.


Aviation...(for the 06z tafs through 06z Thursday night)
issued at 1144 PM CDT Wednesday Jul 29 2015

Much drier air moving into the area from the northwest will bring
VFR conditions to all central Illinois terminals through the next 24
hours. Winds west-northwest 3-7 kts overnight...increasing to 10-12 kts with
gusts 15-20 kts after 17z. Winds becoming west around 5 kts after 00z


Ilx watches/warnings/advisories...


Short term...Bak
long term...geelhart

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