Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 271956

Area Forecast Discussion
National Weather Service Lincoln IL
256 PM CDT FRI MAY 27 2016

.SHORT TERM...(Tonight)
ISSUED AT 256 PM CDT Fri May 27 2016

One weak short wave lifting NNE over northeast IL has scattered
showers and isolated thunderstorms north of CWA. The next short wave
upstream over southeast MO, northeast AR and southern tip of IL is
developing showers and scattered thunderstorms NNE into southern IL
from I-64 south at mid afternoon. 561 dm 500 mb low over far eastern
CO will track into northeast Nebraska by 12Z/7 am Saturday. The
short wave in southeast MO will lift NNE across central IL during
this evening and spread scattered showers and thunderstorms NNE
across the area this evening. Another short wave scheduled to arrive
over central/western IL by early Saturday morning and likely to
bring more showers and scattered thunderstorms. Widespread cloud
cover has limited instablity over central and southeast IL and 0-6
km bulk shear has been weakening during the day. So SPC only has
marginal risk of severe storms late this afternoon and evening over
parts of Knox, Stark and Schuyler counties, while slight risk
remains further west over central/eastern KS, central OK and
southeast Nebraska. Moist dewpoints in the mid to upper 60s over
central IL and around 70F in southeast IL to bring another mild
night with lows 65 to 70F. Breezy south winds 10-20 mph and gusts
20-30 mph to diminish to around 10 mph after sunset.


.LONG TERM...(Saturday through Friday)
ISSUED AT 256 PM CDT Fri May 27 2016

Unsettled weather remains the name of the game across central and
southeast Illinois over the next week. While it certainly will not
be raining all the time, picking periods with zero risk of
showers/storms is proving difficult. However, despite the
uncertainty with respect to precipitation, expect temperatures to
largely remain in the 80s for daily highs and in the 60s for
daily lows.

Initially our main focus remains on the upper-level low that is
currently centered over far eastern Colorado. Pieces of energy
streaming northeast to the east of this circulation will be the
primary driver of our PoPs into Sunday, along with diurnal effects.
The remnants of this upper low finally push north/east of the
forecast area by Sunday, potentially allowing for a mostly rain free
period from later Sunday into Monday.

Then, attention turns to some northern stream energy that will dive
into the plains around the middle of the week. The models are
handling this system quite differently, which makes forecasting the
associated rainfall threat difficult. The spread exists both inter
and intra model with considerable spread in the spaghetti plots. The
operational ECMWF and Canadian models are more progressive, keeping
the main rain threat Wednesday into Thursday. The operational GFS
develops a larger cut-off upper low, and is much slower moving the
system out of the area. This solution would keep a rain risk in
through the end of the forecast period, and may require a downward
adjustment to temperatures as well.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1255 PM CDT Fri May 27 2016

An area of isolated light rain showers was lifting NNE across
central and northeast IL early this afternoon with a weakening
short wave that is about exiting central IL. Another short wave
over northeast AR and southeast MO will lift NNE into central IL
this evening returning chances of showers and chances of
thunderstorms. Carried MVFR ceilings at times along with thunder
chances this evening and early overnight. Yet another short wave
moves into central/western IL Saturday morning returning chances
of showers and thunderstorms. Breezy south winds 14-19 kts and
gusts of 20-27 kts this afternoon will diminish to around 10 kts
this evening and then breezy SSW winds 10-15 kts and gusts to
around 20 kts by 15Z/10 am Saturday.


.ILX Watches/Warnings/Advisories...


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