Area Forecast Discussion
Issued by NWS Central Illinois

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000
FXUS63 KILX 302302
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
602 PM CDT Sun Apr 30 2017

.SHORT TERM...(This evening through Monday)
ISSUED AT 307 PM CDT Sun Apr 30 2017

Continued the flash flood watch east of the IL river through 7 am
CDT Monday, and Peoria and Marshall counties were also added. An
area of light to moderate showers spread northward across central IL
today while the thunderstorms were mainly east over IN and western
KY. SPC day1 late morning update shifted the slight risk of severe
storms east of the Wabash river, while still having a marginal risk
of severe storms over central and eastern IL. A band of convection
was developing along the cold front in central MO and ahead of 996
mb surface low pressure in central KS. This line of developing
convection should spread eastward across CWA during this evening
with the cold front. Between a half and 1 inch of rain is possible
during this afternoon and evening, before showers and thunderstorms
chances diminish overnight behind cold front. Lows tonight to range
from mid to upper 40s over western CWA and lower 50s in eastern IL.

A strong 538 dm 500 mb low over south central KS will eject
northeast to near Door County WI by 7 pm Monday. This will keep low
clouds around along with chances of light rain showers especially
north of I-70. Cooler highs in the lower 50s northern CWA and upper
50s in southeast IL. Windy on Monday with sw winds gusting 30-35
mph.

.LONG TERM...(Monday night through Sunday)
ISSUED AT 307 PM CDT Sun Apr 30 2017

12Z models take strong cutoff upper level low ne into eastern Canada
on Tue while weak surface high pressure ridge moves into the MO
valley. After isolated light rain showers over ne CWA Monday
evening, dry wx expected with decreasing clouds and winds overnight
Monday into Tue. Cool lows Monday night of 39-45F with highs Tue
near 60F from I-74 north and upper 60s in southeast IL.

Models still deepen an upper level trof over the central and
southern Plains Wed and into the mid/lower MS river valley on Thu.
Models have trended a bit slower bringing qpf into southern areas
later Tue night and more likely on Wed and Wed night. Still some
question on how far north shower chances get and stayed close to
consensus model solutions with northern CWA drier and higher pops in
southern CWA. Thunderstorms chances still appear to be south of CWA
on Wed afternoon/evening. Highs Wed in the upper 50s to around 60F
with more cloud cover. Highs Thu in the upper 50s/lower 60s with
coolest readings in east central and southeast IL where lingering
chances of light rain showers.

Models differ with handling deepening upper level trof and cutoff
low in the southeast states Thu night and Friday and consensus kept
slight pops in southeast IL along with more clouds and cooler temps
there with lower 60s Fri while mid 60s from I-55 west. Next weekend
looks drier over CWA as weak surface high pressure ridge settles
into area. Highly amplified upper level flow over the country with
cutoff lows and deep trofs over the northeast U.S. and western
states while upper level ridge in between over the Great Plains.
Slowly moderating temps next weekend with highs in the upper 60s Sat
and upper 60s/lower 70s next Sunday which is closer to normal for
early May.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 600 PM CDT Sun Apr 30 2017

The latest surface analysis indicates a warm front has pushed
north of a Rushville to Lincoln to Champaign line as of 5 pm
and will edge further north this evening. Meanwhile, a cold
front was located over east central Missouri and that will
push across the TAF sites this evening accompanied by showers
and thunderstorms along with MVFR and IFR cigs. The most
concentrated area of low cigs will be north of the front
which will include BMI and PIA, while further south, we will see
a temporary break from the low cigs, outside any shower or
thunderstorm areas, with the MVFR improving to low VFR this
evening. That won`t last that long as soundings suggest a return
to MVFR cigs at SPI, DEC and CMI in the 12z to 15z time frame
Monday. Surface winds north of the warm front will be northeast
to east at 10 to 15 kts, but will be mainly southeasterly at
12 to 17 kts south of the front, with a few gusts to around
23 kts. As a cold front moves through, winds will become
south to southwest and pick to between 15 to 25 kts just
after midnight, with southwest winds of 20 to 25 kts on
Monday with gusts around 30 kts at times through the
afternoon along with the possibility for a few showers.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Monday morning for ILZ029>031-037-038-
041>050-052>057-061>063-066>068-071>073.

Flash Flood Watch through Monday evening for ILZ051.

&&

$$

SHORT TERM...07
LONG TERM...07
AVIATION...Smith



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