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Area forecast discussion 
National Weather Service Lincoln Illinois
1052 am CDT Sat Aug 30 2014

issued at 1052 am CDT Sat Aug 30 2014

Much of central Illinois remains convection-free this morning,
except for the far southeast kilx County Warning Area south of I-70 where showers and
thunderstorms are ongoing. 15z/10am visible satellite imagery is
beginning to show an enhanced band of cu along the Illinois River
that will eventually become a broken line of thunderstorms this
afternoon. Hrrr shows storms developing along the I-55 corridor
after 20z, so have adjusted pops accordingly. Have focused likely
pops along/east of I-55 by mid-afternoon into the early evening
hours. Further west, will only carry low chances along/west of the
Illinois River this afternoon, then dry by evening.


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 Iowa/Illinois 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 Illinois
Sunday where more clouds will be over eastern/se Illinois. Best chances of
convection will be southeast of Ohio River across Kentucky 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 Illinois 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. Storm Prediction Center has much of central Illinois 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 convective available potential energy
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 Illinois. Thus will continue
chances of showers and thunderstorms Tue with best chances (40-50%)
in southeast Illinois closer to frontal boundary while slight chances NW
of Illinois 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 Illinois later Friday into Saturday
of next week increasing chances of showers and thunderstorms followed
by cooler weather next weekend.


Aviation...(for the 12z tafs through 12z Sunday morning)
issued at 658 am CDT Sat Aug 30 2014

Scattered showers continue this morning mainly east of kdec and
could produce isolated MVFR cig/vsby. As daytime heating
begins...expecting intensification of thunderstorm activity.
Location/timing of thunderstorms still uncertain at this time so
have limited mention to thunderstorms in the vicinity after 16z-18z. After 00z...drying
conditions expected to begin spreading eastward across Illinois.
Western taf sites kpia-kspi likely to see fog formation overnight
while eastern taf sites kdec-kcmi could see continued showers
overnight until around 12z and have left vcsh in forecast.


Ilx watches/warnings/advisories...


short term...Onton
long term...07

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