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Area forecast discussion 
National Weather Service Lincoln Illinois
901 PM CDT Monday may 25 2015

issued at 900 PM CDT Monday may 25 2015

A shortwave currently over eastern Texas/OK will be the main weather
feature for central Illinois late tonight and tomorrow. As the shortwave
ejects off to the northeast of its current position...lift and
moisture associated with the feature will develop rain showers and
thunderstorms after midnight. Current short term models tending to
hold off precipitation until later than previous models so have
trended precipitation later...however maintaining likely
precipitation by 7 am across central Illinois. Corridor of preferred
shear/instability overlap looks to skirt through southern Illinois
during the morning...limiting severe weather potential due to
limited surface heating. Have updated gridded forecasts for these
trends and evening temperature/wind trends.


Short term...(tonight)
issued at 259 PM CDT Monday may 25 2015

Lower clouds are lifting and breaking up across the east half of the
forecast area this afternoon...but extensive cirrus shield keeping
skies partly sunny at best there. The western County Warning Area has had some
diurnal cumulus as it is outside the cirrus shield...but this should
fade later this afternoon as some subsidence occurs across that
area. Skies will be partly cloudy for a time this evening...but then
cloud up again later as some of the convective blowoff arrives from
the severe activity currently across the Southern Plains. Latest
high-resolution models keep the forecast area dry this evening with
several suggesting perhaps taking until even 3-4 am before we see
any showers and storms move back in. However...I have ramped up the
pop's quickly after midnight across the west and after 3 am in the
east. With southerly winds staying up around 10 miles per hour or so...little
change needed to the overnight lows...which should be in the 66-68
degree range.

Long term...(tuesday through monday)
issued at 259 PM CDT Monday may 25 2015

Short wave near the Red River along the western Texas/OK border to
eject NE into Illinois on Tuesday likely bringing showers and thunderstorms
most of the day. Have increasing low level jet ahead of this feature
later tonight that will increase chances of showers and
thunderstorms from SW to NE. Showers and thunderstorms will become
more widely scattered SW areas later Tuesday afternoon and over rest of
central/eastern Illinois Tuesday evening. Storm Prediction Center shifted slight risk southeast of
Illinois on Tuesday and now mainly over Kentucky/TN/MS/al where better instability
will be present. Still have a marginal risk of severe storms Tuesday
afternoon from Shelbyville to Danville southeast for hail and gusty winds.
Highs in the upper 70s Tuesday with Lawrenceville near 80f with
dewpoints in the middle to upper 60s (highest in southeast il).

Rather warm and humid weather pattern looks to continue across Illinois
during the rest of the week with daily chance of showers and
thunderstorms. Between 1.5 and 2 inches of rain is expected over
area the rest of this week. Chance of showers and thunderstorms
look higher in southeast Illinois on Wednesday with just slight chance northwest of
the Illinois River by Galesburg as more short wave energy eject NE into
the middle MS and Ohio River valley. Storm Prediction Center has marginal risk of severe
storms Wednesday afternoon mainly south of I-72. Lows tonight mostly in
the middle 60s with some lower 60s northwest of the Illinois River. Highs Wednesday in
the lower 80s and dewpoints in the low to middle 60s.

Upper level ridge building a bit over the eastern states Wednesday night
and Thursday so convection chances look more widely scattered over
central and southeast Illinois. Areas from I-72 north look drier during
this time frame closer to weak high pressure drifting over the Great
Lakes. Highs Thursday in the low to middle 80s with more sunshine possible
and middle 80s on Friday.

Chances of showers and thunderstorms increase again Friday/Sat with a
frontal boundary pushing southeast across central Illinois Saturday and Sat
night. Temperatures to cool behind this front during the weekend
into early next week with highs in the low to middle 70s Sunday. A
cutoff upper level low ejecting from The Rockies into teh Central
Plains by early next week to continue chances of showers and a few


Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 659 PM CDT Monday may 25 2015

VFR conditions in areas of sct025-050 cloud cover with south
winds 10-18 kts this evening. Low cloud cover will dissipate after
sunset then high cloud associated with a shortwave over East Texas
and OK will begin moving into the region. Current timing of lift
and moisture with the approaching shortwave indicate predominant
MVFR conditions in rain showers/isolated thunderstorms and rain likely to begin 10-12z. Some
lifting of predominant ceilings likely in afternoon so have
included thunderstorms in the vicinity with ceilings above MVFR threshold. Shortwave axis
expected to cross late afternoon/early evening Tuesday bringing a
decrease in shower/thunderstorm activity toward the end of the
24-hour taf forecast period. Winds continuing S 10-18 kts until
18z...shifting toward SW in afternoon.


Ilx watches/warnings/advisories...


short term...geelhart
long term...07

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