Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 210154
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
854 PM CDT FRI MAY 20 2016

.UPDATE...
Issued at 848 PM CDT Fri May 20 2016

An upper-level low, currently centered over Illinois, will
continue to lift northeast overnight. An associated surface low
is already east of the state and is currently tracking up the Ohio
River Valley. The bulk of the limited rainfall associated with
this system is east of the forecast area, although there are still
some spotty sprinkles/light showers over mainly east-central
Illinois.

The rainfall risk will continue to wane overnight as the system
pulls away, but expect clouds to linger over much of the forecast
area through the night. Overnight lows should be near normal for
much of the area, mainly in the 50s.

Tweaked forecast for latest, mainly PoP & cloud, trends. These
changes did not change forecast significantly.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT Fri May 20 2016

Weak upper low tracking across the Midwest bringing some light
precip...mainly sprinkles throughout the day...along with plenty of
mid level cloud cover.  For the overnight...the mid level clouds
likely to hang around...and have adjusted tonight`s lows to
reflect that. In addition, sprinkles will likely continue...with
some low chances for measurable precip in the east nw of a weak
developing surface low. Not many changes for the overnight...just
low chances for precip, and winds becoming increasingly northerly
in the wake of the low.

.LONG TERM...(Saturday through Friday)
ISSUED AT 242 PM CDT Fri May 20 2016

The upper low and any lingering rain chance in our southeast counties
will finally push away from our area later Saturday morning, which
should allow a decrease in cloud cover during the day as upper level
heights slowly build over the region. This should bring quiet weather
to our area through Monday along with a warming trend as afternoon
temperatures rise into the 70s Saturday and close to 80 by Sunday
with lower 80s possible by Monday as southerly winds build into
the Midwest.

Another deep upper low will push into the western U.S. this weekend
allowing the central U.S. ridge to dominate our weather for a few
days into early next week. As the deep 500 mb low shifts northeast
and gradually weakens, it will start to flatten the central U.S.
ridge early next week allowing a frontal boundary to edge closer to
our areas later Tuesday into Wednesday. Most models suggest several
weak shortwaves ejecting from the main western trof and interacting
with the slow moving frontal boundary to our west. It still appears
that our chances for showers and thunderstorms will start to
increase Monday night and unfortunately with this pattern setup next
week, be with us on a daily basis through at least Friday. Trying to
time these low amplitude waves and their associated shower and
thunderstorm chances will be difficult at best, so our POPs really
don`t go much higher than 40 percent in any one time period as the
main focus for showers will be tied into the boundary location.
Most of the deterministic models suggest the front will remain to
our west through most of the week with the latest ECMWF indicating
shortwave energy pushing to our north later on Wednesday/Thursday
which may be enough to bring the front close to our area. The
position and strength of the surface low may be a reflection of
some convective feedback that far out in time, and as a result,
may be shifting the front too far east into the strong surface
ridge.

At any rate, the pattern for much of next week is more active for
our area with moderate instability and decent shear late Tuesday and
especially Wednesday and beyond. With the southwest flow aloft thru
next Friday at least, it will start to feel more like summer around
here with afternoon temperatures in the low to mid 80s and dew
points forecast to be well into the 60s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 655 PM CDT Fri May 20 2016

VFR conditions expected to prevail across central Illinois
terminals through the 00Z TAF valid time. While there will be
considerable cloud cover, especially tonight as an upper-level
disturbance crosses the area, it should remain well into the VFR
ceiling category. A few sprinkles are also possible over the next
few hours, especially at KCMI. Northeast to north winds AOB 10 kts
will prevail through the period as well.


&&

.ILX Watches/Warnings/Advisories...
NONE.
&&

$$

UPDATE...BAK
SHORT TERM...HJS
LONG TERM...Smith
AVIATION...BAK



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