Area Forecast Discussion
Issued by NWS Central Illinois

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000
FXUS63 KILX 290543
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1143 PM CST Wed Jan 28 2015

.UPDATE...
ISSUED AT 705 PM CST WED JAN 28 2015

00z/6pm surface analysis shows 1005mb low over western Iowa with
warm frontal boundary extending southward into Missouri.
Temperatures to the west of the warm front are currently in the
60s across Kansas/western Missouri, while readings further east
across central Illinois remain in the 30s and 40s. As the low
tracks into north-central Illinois, the warm front will push
eastward across the area this evening. While both the 00z KILX and
KDVN upper air soundings remain quite dry, latest radar mosaic
shows a narrow band of weak echoes developing ahead of the front.
High-res model output remains dry until the boundary pushes
further east into Indiana after midnight. Will however carry a
chance for sprinkles across the western half of the KILX CWA this
evening, then further east into east-central Illinois after
midnight as the boundary progresses across the area. Temperatures
will remain nearly steady or even rise a few degrees overnight as
gusty southeasterly winds gradually veer to the southwest. Once
the low pushes into Michigan, strong/gusty northwesterly winds
will develop by Thursday morning. In addition, low clouds
currently across the Dakotas will spill southward into the area.
May even see a few light rain/snow showers on the back side of the
departing system Thursday morning, particularly along/north of the
I-74 corridor.

&&

.SHORT TERM...(Tonight)
ISSUED AT 329 PM CST WED JAN 28 2015

A low pressure system currently centered over western Iowa will
track eastward across northern Illinois from around midnight to 6
a.m. tonight. As it does so, a warm frontal boundary followed by a
cold front will push across central Illinois in quick succession.
The warm front will cause temperatures to remain steady or even rise
slightly through much of the night, with primarily upper 30s and
lower 40s expected, followed by little increase in temperatures
after sunrise as the cold front pushes east across the area. This
system will be relatively moisture starved, so precipitation amounts
are expected to be very light. A potent surface pressure gradient
will be present with this system, keeping breezy winds going through
the night in the neighborhood of 15 to 20 mph with some higher
gusts. Winds will gradually turn from SSE this afternoon to SSW
overnight, shifting abruptly to northwest after the cold frontal
passage.

&&

.LONG TERM...(Thursday through Wednesday)
ISSUED AT 329 PM CST WED JAN 28 2015

Main concern today is the system over the weekend.
Morning upper air shows weak wave to move through tonight. Then
continued general northwest flow aloft as a cutoff low in the
southwest begins to drift to the east. A piece of shortwave energy
comes out from the southwest on Saturday and develops overrunning
pcpn Saturday night, as another wave in the northwest flow tracks to
the southeast into the area for Sunday. The result is a prolonged
period of light lift over the area Saturday night into Sunday
evening, which will produce light pcpn. Temperatures will be cold
enough for all over cwa but the far southeast to result in all snow
most of the period. At this time, lift seems to be light and just
the prolonged period from the 2 systems causing the pcpn. Will still
have to watch it as periods near to see if lift increases and thus
the resultant amounts. Kept amounts similar in the grids as previous
run at this time.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1143 PM CST WED JAN 28 2015

Low pressure currently centered over eastern Iowa will track across
north-central Illinois tonight, then into Michigan by Thursday
morning. A tight pressure gradient ahead of the low will continue
to provide gusty southeasterly winds that will gradually veer to
the southwest after midnight, before veering sharply to the northwest
after FROPA between 12z and 15z Thu. Forecast soundings remain
quite dry, although models are hinting at perhaps a few light
showers near the low track, so have included VCSH at the I-74
terminals Thursday morning. VFR conditions will prevail until the
front passes and winds become northwesterly, at which time MVFR
ceilings currently over the Dakotas and western Iowa will spill
southeastward into the area. Based primarily on HRRR timing, have
introduced MVFR ceilings at KPIA by 10z, then further east to KCMI
by 13z. Once the low clouds arrive, they will stick around through
Thursday afternoon. Winds will be quite strong as well, with
northwesterly gusts in the 25 to 30kt range.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...Onton
LONG TERM...Goetsch
AVIATION...Barnes






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