Area Forecast Discussion
Issued by NWS Central Illinois

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KILX 181950
AFDILX

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

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CDT THU SEP 18 2014

1026 mb Canadian high pressure just north of MI will settle southeast
into New England by midday Friday. Aloft, northwest flow persists,
with any active short waves in the near term expected to stay south
of the forecast area. A few cumulus clouds especially in our sw CWA
this afternoon will dissipate at sundown leaving clear skies
tonight and east winds will become light again near 5 mph after
sunset. Patchy shallow ground fog to develop again overnight
especially near rivers like the IL river and lift by mid Friday
morning. Fog should be more limited than the past 2 nights with
wind speeds a bit higher. Similar MAV/MET guidance lows in the
upper 40s to near 50F looks on track with some mid 40s in parts of
east central IL where dewpoints currently in low to mid 40s.

&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CDT THU SEP 18 2014

High pressure centered over the Great Lakes will continue to provide
dry conditions all the way back into Illinois through early Saturday
morning. Warmer conditions are expected for Friday as southerly
winds develop behind the departing high pressure. The thermal ridge
in the 850-700 mb layer will initially surge northward into Iowa
and SW Wisconsin, before sliding east into Illinois for Saturday.
That will result in highs reaching the upper 70s on Friday and
lower 80s on Saturday.

The 12z model suite continues to show a cold frontal passage on
Saturday afternoon into Sat night. We still expect a dry morning on
Saturday with storms erupting during the afternoon, mainly northwest
of I-55 through 6 pm. Instability parameters continue to look
favorable for thunderstorm development, especially during the
daylight hours NW of Lincoln. SPC has only a 5% risk for severe in
that area, and no widespread severe weather is anticipated. The main
threat would be for strong wind gusts with the deeper convection.

As the front progresses to the SE Sat evening, storm chances will
expand to I-70 through midnight, then SE of I-70 after midnight.
Depending on how much the front slows down Saturday night, we could
see a few showers/storms lingering mainly SE of I-70 Sunday morning.

Beyond that, high pressure will return to dominate the weather from
Monday through at least midweek and possibly the rest of the week.
Dry and cooler than normal conditions will be the rule during that
period. A warming trend could begin on Thursday, as highs climb
into the mid to upper 70s again.

&&

.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.

&&

$$

SHORT TERM...07
LONG TERM...SHIMON
AVIATION...07





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.