Area Forecast Discussion
Issued by NWS Central Illinois
FXUS63 KILX 120140
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
840 PM CDT SUN OCT 11 2015
ISSUED AT 840 PM CDT SUN OCT 11 2015
A steady light southerly breeze around 10 mph will continue
overnight as pressure gradients tighten ahead of a low pressure
trough approaching via the northern Plains. This will keep
temperatures rather mild...with lows only reaching the 50s. Skies
will be mostly clear early on...with more high clouds spreading
over the area toward morning. Current forecast is on track with
these features...and no significant updates expected this evening.
ISSUED AT 245 PM CDT SUN OCT 11 2015
High pressure slides off to the southeast this afternoon as another
developing storm system moves across the southern tier of Canada.
As a result, breezy southwesterly winds have dominated the day.
Then overnight tonight...will be similarly quiet with warmer
southwesterly winds and clear skies. Tomorrow morning, the sfc trof
associated with the storm system to the west should move into the
region and bring with it a significant wind shift to more
.LONG TERM...(Monday through Sunday)
ISSUED AT 245 PM CDT SUN OCT 11 2015
The extended forecast continues to center around a couple of systems
that will progress across Illinois. The first on Monday and the
second Thursday night. The upper flow pattern will generally
maintain a northwest flow regime through next weekend, with the
exception being Monday and Monday night as a strong low moves
through the Great Lakes.
We will exit the abnormally warm side of the upper ridge on Monday,
as a cold front pushes across IL during the day. Southeast of I-72
will enjoy one more day of warmth due to the front arriving during
the afternoon and cold air delayed enough behind the front for highs
to reach the upper 70s to around 80.
Forecast soundings continue to show very limited moisture across our
forecast area as the front arrives on Monday, so we kept a dry
forecast. Gusty N-NW wind behind the front Monday afternoon remains
the primary focus, with speeds reaching 25-35 mph. Fire weather
concerns are also elevated, with winds and dry fuels across the
area. The Minimum RH values will remain above Red Flag criteria of
25%, so will just mention heightened fire weather awareness in the
HWO and FWF products for now.
A much weaker wave is indicated for Wednesday, and now the models
are pushing the main energy along far SW Illinois and the
Mississippi River instead of into central IL. That system should
remain a non-factor in our sensible weather.
Of more concern is the low pressure system and cold front progged to
arrive in western IL late Thursday afternoon and progress across our
forecast area Thursday night. Despite widely varying solutions on
the position of the primary central low, the 12z ECMWF, GFS and
Canadian all indicate enough moisture and dynamics across Illinois
for scattered showers to develop along the cold front Thursday
night. We kept the model blend slight chance PoPs, but those chances
may climb over the next few model runs if current trends continue.
Cool high pressure behind that front will bring our coldest air of
the next week. Lows will approach the 30s Friday night and Saturday
night for our northern areas from Galesburg to Lacon. Highs on
Saturday will be in the upper 50s to low 60s.
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 636 PM CDT SUN OCT 11 2015
VFR conditions expected for the next 24 hours...however periods of
gusty winds and low-level wind shear expected.
Overnight...strengthening low-level jet expected as a pressure
trough approaches...with the trough to cross central IL 10Z-15Z.
This should bring strong enough wind speeds at 1500 ft AGL that 30
kts or greater wind shear expected from around 03Z-12Z. Winds to
remain breezy through the afternoon...with increasingly gusty
conditions expected toward late afternoon...with gusts 25-30 kts
expected after 21Z.