Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 242337

Area Forecast Discussion
National Weather Service Lincoln IL
637 PM CDT SUN APR 24 2016

.SHORT TERM...(Tonight)
ISSUED AT 259 PM CDT Sun Apr 24 2016

Strong 995 mb surface low pressure over central SD this afternoon
will track eastward along a warm front into sw MN by 12Z/7 am Monday.
A prefrontal trof ahead of the cold front will move into nw IL late
tonight and bring isolated showers/thunderstorms to the IL river
valley mainly nw of the IL river after 09Z/4 am. Mostly clear to
prevail most of tonight over southeast IL while skies become partly
to mostly cloudy over central IL with more clouds moving into the
IL river valley. Milder lows overnight in the upper 50s to near 60F
with coolest readings near the Wabash river. Breezy SSW winds 10-17
mph and gusts 20-25 mph this afternoon to veer more southerly and
range from 7-14 mph tonight after sunset with lightest winds over
southeast IL.

.LONG TERM...(Monday through Sunday)
ISSUED AT 259 PM CDT Sun Apr 24 2016

The first in a series of weather systems to impact the area this
week will arrive Monday. While the upper level wave driving the
first system looks impressive over the Plains on water vapor imagery
at the moment, it is expected to weaken significantly by the time it
arrives. The airmass ahead of the frontal boundary associated with
the system is expected be at least slightly capped, and this will
limit or prelude pre-frontal precipitation. Shower/storm chances
will increase Monday night/early Tuesday as it front sinks south
through the forecast area. However, rainfall amounts should be
rather trivial, with most areas seeing less than one quarter inch.

After a brief break, the next system will arrive by midweek, with
the best shower/storm chances from late Tuesday night into Wednesday
night. While not as pronounced as yesterday, the model consensus has
continued to shift a little further south with the track of this
system. As mentioned yesterday, these trends make sense and are
accepted given the blocky downstream pattern across Greenland and
eastern Canada. The main impacts of these shifts are a southward
adjustment of the associated severe weather risk (mainly over
southern Illinois), less thunderstorm coverage overall, and cooler
temperatures across most of the forecast area. As models continue to
shift, it is conceivable that lower thunder chances and cooler
temperatures will be needed than are contained in current forecast.

The final system of the week is progged to arrive by next weekend,
with the models trending a little faster overall over the past
couple of runs. However, the model consensus here is much less strong
than with the first two systems. At this point, it appears the
highest shower/storm chances will occur Saturday & Sunday, but this
is certainly subject to additional adjustment given the lingering

Temperatures for the week should average at or above normal across
most of the forecast area. However, given the more southerly track
of the mid-late week systems, future forecasts may see temperatures
trending a little cooler than normal some days.


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 637 PM CDT Sun Apr 24 2016

VFR conditions will prevail at all TAF sites next 24hrs. Satellite
trends indicate only cirrus being over the area throughout the
night. Then models indicate remnants of this evenings convection
out west will make it`s way toward the area and bring some lower
clouds to central IL. Broken cigs around 5-4kft to be expected at
PIA/BMI/SPI during the morning hours and then likely continue into
the afternoon. DEC and CMI will probably only see scattered clouds
at the same level, given the system should also be dissipating as
it moves east. Thinking only vcsh possible at PIA during the
morning hours. All other sites should remain dry. Winds will be
south-southeast tonight with speeds just over 10kts. Then winds
will be south-southwest tomorrow with gusts over 25kts.


.ILX Watches/Warnings/Advisories...


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