Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 300446

Area Forecast Discussion
1146 PM CDT Sun Mar 29 2015


Periods of showers that impacted central and southeast Illinois
earlier today were well ahead of the surface cold front that is
currently crossing the area. The cold front is roughly along the
I-55 corridor at this time. The front itself is coming through
dry, but is associated with a band of clouds. Expect the front to
quickly exit to the east over the next few hours, with skies
rapidly clearing in its wake (where it has not already done so).
Then, building high pressure will help keep quiet conditions in
place for the balance of the night.

Going forecast had this quiet weather regime well handled. Only
need to update for the latest hourly trends and to remove
precipitation wording in the east from the text products.


.SHORT TERM...(Tonight)

Initial band of light rain had largely moved into Indiana by about
12:30 pm. Secondary batch of showers was trying to form at mid
afternoon, but low level air mass remains rather dry, and cloud
heights are mostly above 7,000 feet as well, so this has been
struggling to produce much more than sprinkles. Wind gusts 35-45 mph
formed over the western CWA this morning and have shifted to more
across the east this afternoon, but still some gusts near 25 mph
over the western CWA as well.

Frontal boundary was shown on 2 pm surface map from western
Wisconsin, across eastern Iowa, to west central Missouri. This is
progged by the short-term models to be near Galesburg by 6 pm and
along the I-70 corridor toward 10 pm. HRRR has been persistent in
developing a narrow band of showers along it, the initial hints of
which are seen on regional radar mosaics over southwest Wisconsin.
However, while some additional moisture will spread into the
forecast area the remainder of the afternoon (perhaps getting dew
points up to around 40), not terribly confident that this will have
any better luck reaching the ground this far to the south. Have
maintained some slight chance PoP`s early evening across about the
east half of the forecast area, but went dry everywhere by 10 pm.
Clearing line is not too far away in northwest Iowa, and most of the
CWA should be mostly clear by midnight.


.LONG TERM...(Monday through Sunday)

A rather quiet weather pattern to start the week off with as our
area will be influenced by northwest flow aloft. Surface high
pressure will drift south of our area during the day Monday bringing
warmer conditions to the forecast area while a shortwave trof shifts
southeast into the upper Midwest late in the day. This feature has
been expected to keep its more widespread cloud cover and rain to
our north and that trend is still holding with this mornings 12z
model runs. The boundary should push across the area Tuesday
afternoon and be close to the Ohio River Valley Tuesday evening as
surface high pressure shifts south from the upper Great Lakes into
our area at night. Upper level ridging is then forecast to build over
the region on Wednesday in response to a rather potent upper level
shortwave forecast to move across the northern Rockies Wednesday. The
southerly flow ahead of the upper wave is forecast to bring in some
mild air to the region Wednesday with afternoon highs in the upper 60s
east to the lower or middle 70s far southwest.

Have chosen the slower solutions (12z ECMWF and Canadian models)
with respect to the timing of the cold front and showers and storms
into our area late Wednesday night and especially during the day on
Thursday. Fairly decent instability and shear parameters ahead of
the upper wave to our west late Wednesday but based on the projected
timing of the front into our area, the storms should be less intense
as they track into our area early Thursday morning with the better
chances for showers and storms across the forecast area during the
day on Thursday. The front will get pushed southeast into the Ohio
River Valley Thursday night with models suggesting another shortwave
to induce a weak wave on the boundary with a renewed threat for
showers spreading back over the forecast area again Thursday night
into parts of Friday with the higher POPs shifting into southeast
Illinois during the day Friday before the system pushes away from
the area next weekend bringing in cooler weather for at least the
start of the Easter weekend.

After a nice recovery in temperatures starting tomorrow, which should
last through at least Thursday, the mercury will drop off to below normal
levels once again thru Saturday before we see temperatures start to moderate
again on Easter Sunday. Precip-wise, after our slight chance POPs in
the southeast Friday evening, will keep the remainder of the forecast
dry for now with longer range solutions suggesting some shower chances may
return late Sunday night or next Monday.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)

VFR aviation weather conditions expected across the central
Illinois terminals through the 06Z TAF valid time. A cold front
has cleared the area within the past few hours, with high pressure
expected to be dominant for the duration of the forecast. Cloud
cover is expected to be minimal overall, with winds becoming gusty
out of the the southwest for much of the daytime hours Monday.




SHORT TERM...Geelhart
AVIATION...Bak is the U.S. government's official web portal to all federal, state and local government web resources and services.