Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 300903
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
403 AM CDT Sat Aug 30 2014

.SHORT TERM...(Today and tonight)
ISSUED AT 401 AM CDT SAT AUG 30 2014

Lift associated with an upper level shortwave trough over eastern
Iowa moving east-northeastward this morning is providing a focus for
a line of convection moving into western Illinois while a weaker
line of showers roughly along I-57 continues in eastern Illinois.
Cold front associated with the trough to our west is expected to
move to around to IA/IL border and stall out as the upper level
shortwave lifts northeastward bringing a continued focus for
precipitation for much of the next 24 hours. Rich moisture of close
to 2 inches will continue to stream into southeast Illinois to bring
the best chances for precipitation in that region. Tonight, as the
main trough shifts eastward, drier air continues to push eastward
allowing drier conditions to spread eastward into Illinois. As a
result, have pops trending downward overnight. Temperatures will be
down slightly today and tonight.

&&

.LONG TERM...(Sunday through Friday)
ISSUED AT 401 AM CDT SAT AUG 30 2014

Lingered a chance of showers and thunderstorms over southeast IL
Sunday where more clouds will be over eastern/se IL. Best chances of
convection will be southeast of Ohio river across KY where short
wave energy will be. Highs in the low to mid 80s Sunday (warmest
over western areas) and humid with dewpoints mostly in the lower
70s. Dry conditions across area Sunday evening then have chance of
showers and thunderstorms returning to areas nw of I-55 overnight
Sunday night. This due to approaching strong upper level trof over
Pacific Northwest that brings a cold front se through IL Monday
night. Quite warm and humid again on Monday with highs in the 80s
and dewpoints in the lower to middle 70s. Chances of showers and
thunderstorms increase from nw to se during the day Monday with
highest chances Monday afternoon/evening, gradually shifting chances
se overnight Monday night. SPC has much of central IL in a slight
chance of severe storms Monday afternoon/evening for damaging winds
and large hail. Surface to 6km bulk shear around 40 kts and CAPES
2-3K J/Kg supports this risk of severe storms from I-70 nw.

Upper level flow to become zonal by middle of next week and frontal
boundary likely not to get too far south of IL. Thus will continue
chances of showers and thunderstorms Tue with best chances (40-50%)
in southeast IL closer to frontal boundary while slight chances nw
of IL river. Just slight chances by Wed-Thu night and quite warm and
humid with highs in the mid to upper 80s and even approaching
lower 90s over southern areas Thu and Friday. This is due to
upper level ridge of 593 dm 500 mb high building over KY/TN. Next
frontal boundary to press se toward IL later Friday into Saturday
of next week increasing chances of showers and thunderstorms followed
by cooler weather next weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1155 PM CDT FRI AUG 29 2014

Spotty showers and possibly a thunderstorm are expected across
central Illinois overnight, and some may impact a TAF site.
However, confidence in coverage/timing is too low to go above a
VCSH mention. By midday Saturday, a cold front will be pushing
into the area producing more numerous convection, with the bulk of
the precipitation apt to be thunderstorms. The highest coverage
should impact east central Illinois, including KDEC/KCMI. Still
plan to limit mention to VCTS at this time. By Saturday evening,
the front should be far enough east to end the threat at
KPIA/KBMI/KSPI, but KDEC/KCMI may still see a storm or two.
While predominantly VFR conditions are expected through the
period, MVFR or lower is briefly possible with thunderstorms.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SHORT TERM...ONTON
LONG TERM...07
AVIATION...BAK






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