Area Forecast Discussion
Issued by NWS Central Illinois
FXUS63 KILX 261209
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
609 AM CST THU NOV 26 2015
ISSUED AT 333 AM CST THU NOV 26 2015
An elongated area of low pressure in the Plains will slowly approach
Illinois today, as south-southwest flow feeds moisture into the
area. The relatively close proximity of a strong 1038mb surface high
to the east will prompt surface winds to become quite gusty, with
speeds in the 20 to 35 mph range for much of the day. Due to the
moisture being mainly confined to the lower levels initially, we
expect mainly spotty showers through the day, with some light
drizzle possible this morning before mixing helps lift the LCL.
Clouds will blanket the area all day, limiting the diurnal swing.
Highs will only climb around 10 degrees above sunrise readings.
Warmer than normal temperatures will prevail, as highs reach the
lower 60s in most areas, with mid 60s possible toward Jacksonville.
.LONG TERM...(Tonight through Wednesday)
ISSUED AT 333 AM CST THU NOV 26 2015
An active weather pattern will be in store for central and southeast
Illinois through early next week. Weak isentropic lift and shallow
moisture today will increase tonight as cold front over central IA
into nw MO moves toward Galesburg and Macomb by midnight tonight and
across the IL river valley overnight. Chances of rain to increase
from nw to se during tonight along with heavier qpf amounts over IL
river valley of nw IL this evening and into central IL overnight and
eastern/se IL Friday as cold front moves through that part of the
state. Precipitable water values peak around 1.25 inches to support
moderate to heavier rainfall at times tonight and Friday. Lows
tonight to range from lower 40s nw of the IL river to the low to mid
50s over east central and southeast IL which stays on warm side of
the front through the night. Morning highs Friday range from low to
mid 40s over IL river valley to the upper 50s in southeast IL. Temps
will likely slowly slip behind the cold front during the day.
Cold front settles toward the Ohio river Friday night and into
central KY this weekend while surface low pressure and short wave
lifts ne into mid MS river valley. This to bring overrunning setup
of showers over central and especially southeast IL from Friday
night into this weekend. Will increase pops over southeast IL to
likely to categorical along with heavier qpf amounts. Northern cwa
will have lower pops and lighter qpf and could even be dry at times
especially north of Peoria. Rainfall amounts tonight through
Saturday night will range from 1-2 inches with highest amounts in
southeast IL. Flash flood guidance values are 1.5-2 inches per hour
and 2.3-3 inches per 6 hours, and 3-5 inches in 12-24 hours. We
should stay below these values so will not issue a flood watch but
some rivers and streams could approach flood stage this weekend like
Clay City on the Little Wabash river.
Still appears there could be a mix of precipitation northern CWA
friday night especially overnight but amounts of qpf are much
lighter and if very little if any accumulations. Cooler highs in the
low to mid 40s this weekend with lows in the 30s, with upper 30s to
near 40F in southeast IL.
Strong 500 mb low pressure of 542 dm over NV to slowly move across
the central Rockies into this weekend, and then eject ne into WI by
Tue morning. This will continue a good chance of showers ahead of it
over IL Monday and Monday night and then diminish to 20-30% chances
on Tue with highest pops ne of I-74 on Tue. Could be a mix of light
precipitation over northern/nw CWA Monday night into Tue morning.
Dry conditions finally appears to return Tuesday night and Wed over
central/se IL. Seasonably cool temperatures continue during 1st half
of next week with highs in the upper 30s to mid 40s and coolest from
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 602 AM CST THU NOV 26 2015
Cloud cover will continue over the next 24 hours, with VFR clouds
at the beginning of the TAF period. MVFR cloud heights are
expected to develop this afternoon as a cold front approaches from
the west. Spotty showers will be around today as well, but they
should stay light and/or isolated through sunset, so continued
with VCSH mention for now. The winds should be gusty out of the
south through the period, but significantly stronger winds just
off the deck will still produce LLWS today, as the guidance
forecasts 50 kt winds as low as 925 mb through the period.
Rains will become more widespread tonight, as the front arrives in
Illinois. Visibility will drop in the heavier rains as cloud
heights drop to IFR and possibly LIFR. Winds will begin to shift
around to the NW for PIA and BMI toward the end of the 12z TAF
period, after FROPA.