Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 250447

Area Forecast Discussion
National Weather Service Lincoln IL
1147 PM CDT Thu May 24 2018

Issued at 900 PM CDT Thu May 24 2018

Quiet weather will persist across central and southeast Illinois
overnight as a ridge of high pressure slowly pulls away from the
area. Light winds will trend more southerly on the back side of
the ridge by late tonight, helping mild temperatures to persist.
Going forecast is in good shape, with only minor tweaks needed to
the hourly trends.


.SHORT TERM...(This evening through Friday)
ISSUED AT 250 PM CDT Thu May 24 2018

Quiet weather to hold across our area through the night as high
pressure continues to edge further off to our east. The ridge
axis extends west into central Illinois and this should bring
one more pleasant night to the area with mild temperatures and
comfortable humidity levels. Early morning lows are expected
to drop into the low to mid 60s with the warmer readings over
west central Illinois. Along and west of the Mississippi River,
surface dew points were in the mid to upper 60s and as the surface
ridge axis shifts well off to our east on Friday, we should see
the dew points on the rise across our area as well, especially
over the western half of the forecast area.

A weakening upper level shortwave is forecast to push across the
Great Lakes by the end of the day helping to drag a frontal
boundary closer to the Midwest. The combination of afternoon
temperatures around the 90 degree mark and dew points well into
the 60s over most of the area should bring about Mixed Layer Cape
values of near 2000 J/KG, especially over western IL. Widely
scattered thunderstorms are forecast to develop by mid to late
afternoon with the activity continuing into the evening before
gradually dissipating with the low of daytime heating. Several of
the high resolution convective allowing models suggest convection
to hold off until later tomorrow evening as a complex of storms
tracks south-southeast out of Wisconsin and northeast Iowa in a
weakening state bringing showers and storms to at least the
northern part of the forecast area. 0-6km bulk shear values not
very impressive in our area which may tend to limit coverage any
severe threat across our area, but if the storms do develop
during the mid and late afternoon hours, a few of the stronger
storms will be capable of producing strong gusty winds and
possibly some hail, although freezing levels will be quite high
later tomorrow. Afternoon temperatures tomorrow will be right
around 90 degrees.

.LONG TERM...(Friday night through Thursday)
ISSUED AT 250 PM CDT Thu May 24 2018

Models agree that the aforementioned southern Great Lakes
shortwave will track off to our east by Saturday morning.
Just what boundaries are left over from any of the convection
that may affect parts of our area late Friday will play a role
in any redevelopment during peak heating Saturday afternoon,
although any coverage looks limited at this time as the upper
level wind fields will be quite light across the area.

Upper level heights are then forecast to build over the central
U.S. into at least the first half of the new work week resulting
in hot and humid conditions across the forecast area. Further
south, an upper level wave will track across the Gulf Coast states
limiting any northward transport of deep moisture into our area,
thus, precip chances look rather limited at this point with no
more than 20-30 POPs in the afternoon and early evening hours, and
that would be starting back up again on Tuesday, with POPs slowly
increasing towards mid-week as the combination of a Northern
Plains shortwave and the closed upper low coming out of the Gulf
Coast try to merge over the central U.S. Until then, above normal
temperatures to continue along with limited rainfall across the


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1146 PM CDT Thu May 24 2018

High pressure will continue to push off to the east tonight, with
southerly winds increasing across central Illinois on Friday.
Moisture levels will be increasing along with the southerly winds,
leading to more cloud cover on Friday. While VFR conditions are
expected for most, if not all, of the 06Z TAF valid time,
isolated shower/storms are possible from about midday Friday into
Friday night. However, precipitation coverage is expected to be
too low to go above a VCSH mention in the TAFs at this time.




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