Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 271147

Area Forecast Discussion
647 AM CDT Fri Mar 27 2015

.SHORT TERM...(Today)

An upper level shortwave trough axis will cross central IL early in
the morning with deep northerly flow continuing to advect cold air
into the region through the day today. Brisk northerly winds 10 to
15 mph will continue much of the day before beginning to taper off
late in the afternoon as surface high pressure approaches from the
west, weakening pressure gradients over the area. Combined with
highs in the upper 30s and lower 40s, it will be a fairly chilly day
for this time of year. Cloud cover will be prevalent early in the
morning as the trough axis crosses, then tapering off west to east
throughout the day as subsidence behind the trough sets in. Some
lake-enhanced cloud cover and flurries could affect Vermilion and
Edgar counties late this morning into early afternoon, but otherwise
not much indication that cloud cover associated with the shortwave
will produce any precipitation.


.LONG TERM...(Tonight through Thursday)

A cold night ahead for central and southeast IL as 1029 mb Canadian
high pressure over western Ontario into the eastern Dakotas settles
into the western Great Lakes by Saturday morning and ridges south
into IL overnight into Sat morning. Meanwhile another northern
stream short wave dives se across central/ne IA/MO overnight and
keeps it light snow chances sw of IL though may get some clouds in
west central and sw IL. Lows tonight in the upper teens ne areas
where less clouds and lower 20s sw areas. This would be above record
lows on Sat morning Mar 28 ranging from 5-15F.

Short wave trof passes across IL Sat morning and into KY/TN by
sunset Sat while 1028 mb Canadian high pressure settles into the
Ohio river valley. This to ensure another chilly day across IL with
highs in the lower 40s and even some upper 30s in east central IL.
Some passing clouds Sat morning give way to more sunshine Sat

00Z models continue dry conditions over central and southeast IL Sat
night as clouds increase overnight over northern areas. Lows Sat
night in the mid 20s eastern IL and upper 20s to near 30F central
and western IL, with temps nearly steady or slowing rising later Sat
night as southerly winds start to increase and clouds increase
especially over IL river valley. Strong surface low pressure around
990 mb passes north of Lake Superior on Sunday as it tracks eastward
over southern Canada and brings a cold front se across IL Sunday
evening. Have increase chances of rain showers during day Sunday
especially Sunday afternoon. Could be cold enough early Sunday
morning for mix of precipitation over IL river valley in nw counties
if precipitation starts prior to 9 am. Breezy ssw winds Sunday ahead
of cold front to start the warmup into the low to mid 50s. Rain
shower chances diminish from nw to se Sunday night and mainly occur
Sunday evening. Lows Sunday night in mid 30s central IL and upper
30s in southeast IL.

Upper level flow becomes more zonal by early next week and this to
bring milder Pacific air into IL during early and middle part of
next week. Weak surface high pressure settles into the mid MS river
valley Monday and returns dry weather with mostly sunny skies.
Milder highs Monday in the upper 50s and lower 60s. A surface low
tracking east across the Great Lakes Monday night to bring slight
chance of light rain showers north and ne of I-74 with most of rain
showers passing north of central IL. Milder highs in the mid to
upper 60s expected Tue and Wed with low to mid 60s on Thu. Next wx
system to bring chances of rain showers and isolated thunderstorms
Wed afternoon and Wed night. Have slight chances of showers
lingering over eastern/se IL Thu then another chance of showers
arriving next Friday.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)

Mainly VFR aviation weather conditions expected across the central
Illinois terminals through the 12z TAF valid time. Breezy north
winds will decrease and shift to more easterly as high pressure
drifts into the region. SCT-BKN cloud cover at 4-6 kft AGL across
central IL in the morning will gradually clear from the west
through the day. Local MVFR ceilings will take place through the
early afternoon in eastern sections of the state along with a
possibility of isolated -SHSN associated with lake effect from
Lake Michigan.




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