Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 181736
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1236 PM CDT Thu Sep 18 2014

.UPDATE...
ISSUED AT 955 AM CDT THU SEP 18 2014

Updated the forecast to removed mention of patchy fog early this
morning since it has dissipated by mid morning. A picture perfect
day ahead with mostlyl sunny skies central IL and partly sunny
skies south of I-70 as scattered cumulus clouds appear by midday.
Highs in the lower 70s and comfortable dewpoints in the low to mid
50s. Gentle ENE winds of 5 to 10 mph. Nice weather through Friday
is compliments of 1026 mb Canadian high pressure just north of the
Great Lakes which is settling se into the Great Lakes region
through Friday.

&&

.SHORT TERM...(Today)
ISSUED AT 244 AM CDT THU SEP 18 2014

Today, central and southeast Illinois will be strongly under the
influence of a large surface high, currently centered over northern
Ontario. Aloft, northwest flow persists, with any active short waves
in the near term expected to stay south of the forecast area.

The light winds and mostly clear skies (more clouds exist across
southern Illinois) have allowed patchy fog to develop early this
morning. The fog is locally dense in spots, but temperature/dew
point spreads in most areas suggest the fog will not get as
widespread as last night.

Once the early morning fog burns off, the rest of the day should be
quiet and a little warmer than yesterday. The dry easterly low level
flow should help minimize diurnal cloud development. While
significant warm advection is not expected to occur, more abundant
insolation today should boost high temperatures a few degrees from
yesterday, with highs mainly in the lower 70s.

&&

.LONG TERM...(Tonight through Wednesday)
ISSUED AT 244 AM CDT THU SEP 18 2014

Forecast area remains on periphery of high pressure over the Great
Lakes into Friday, keeping conditions dry. Focus into the weekend
remains with the shortwave current along the British Columbia coast.
Latest model guidance slows the wave down a tad as it moves into the
upper Midwest, although there is enough progress to warrant 40%
PoPs by Saturday afternoon across the northwest third of the CWA.
CAPEs forecast to be 1500-2500 J/kg by late afternoon, although
shear values are a bit more modest. Highest PoPs expected in the
evening before storms weaken after midnight. Have lingered some
PoPs across the southeast third into Sunday morning, before the
front reaches the Ohio River.

High pressure still expected to dominate the Midwest from Monday
through midweek, keeping us dry. Temperatures expected to be cooler
than normal again early next week, with a northwest flow to start
the week. By midweek, upper ridging will be building across the
middle of the nation, allowing for a warming trend.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1235 PM CDT THU SEP 18 2014

VFR conditions should mainly prevail next 24 hours across the
central IL airports aside from possible MVFR visibilities
restrictions with patchy shallow ground fog overnight mainly along
river valley like at PIA near IL river. Any patchy shallow fog
that develops during overnight will dissipate quickly between
13-14Z Fri. Few to scattered cumulus clouds around 4k ft to appear
this afternoon and dissipate at sunset, and redevelop by midday
Friday. 1026 mb Canadian high pressure just north of the MI will
settle se into New England by 18Z/1 pm Friday. East winds near 10
kts with gusts around 15 kts at times this afternoon to diminish
to 4-7 kts after sunset and veer SSE near 10 kts after 14Z/9 am
Friday.

&&

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

&&

$$

UPDATE...07
SHORT TERM...BAK
LONG TERM...GEELHART
AVIATION...07





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