Area Forecast Discussion
Issued by NWS Central Illinois

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165
FXUS63 KILX 190841
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
341 AM CDT Thu Apr 19 2018

.SHORT TERM...(Today and tonight)
ISSUED AT 330 AM CDT Thu Apr 19 2018

Issued another freeze warning for our 8 southeast IL counties
along and south of I-70 overnight from 1-8 am cdt Friday. Clear
skies and light to calm winds to give good radiational cooling
with lows of 28-32F. This is the 3rd freeze waring for southeast
IL this week.

09Z/3 am surface map shows 1002 mb low pressure over central VA
while a weak surface trof hangs back into northeast IL. Meanwhile
a 1031 mb Canadian high pressure extended from southeast Saskatchewan
into the central Dakotas and ridging southward across the central
plains. Radar mosaic shows main area of light snow was over
northeast IL, ne of Pontiac and over northern half of IN, north of
Indy and tracking se. Had scattered flurries over central IL,
north of I-70, early this morning. Aloft a 545 dm 500 mb low was
along the northern OH/IN border and this upper level trof extended
into central IL. Broken to overcast stratocumulus clouds covered
IL early this morning. Chilly temps were in the 32-36F range over
central IL, and 35-39F in southeast IL. Brisk nw winds of 10-17
mph and gusts 18-25 mph was giving wind chills in the low to mid
20s.

Upper level low forecast to lift into the St Lawrence valley and
northern New England during this afternoon, while Canadian high
pressure strengthens to 1034 mb as it drifts into northern/nw IA.
Scattered flurries to push se of CWA shortly after sunrise while
low clouds decrease from nw to se during this morning, giving way
to ample sunshine this afternoon. Highs of 50-55F this afternoon
with NNW winds 8-15 mph and gusts to around 20 mph to make it feel
cooler. High pressure ridge to be over the upper MS river valley
and ridging into IL by dawn Friday. This to bring clear skies,
light winds and a widespread freeze with lows of 26-32F. Being the
growing season has started along and south of I-70, had to issue
another freeze warning overnight for 8 southeast IL counties.

&&

.LONG TERM...(Friday through Wednesday)
ISSUED AT 330 AM CDT Thu Apr 19 2018

Canadian high pressure settles east into the Great Lakes region by
Friday afternoon, while upper level ridge shifts east into the MS
river valley by sunset Friday. Ample sunshine Friday and east to ENE
winds less than 10 mph, with a bit milder highs in the upper 50s and
lower 60s. Clouds to increase over central IL overnight Friday
night while southeast IL stays with fair skies longer during
Friday night. Not as cold Fri night with lows in the mid to upper
30s Friday night, coolest in eastern IL.

A 550 dm 500 mb low off the central CA coast will track into the 4
corners are by midday Friday, and into western OK and nw TX
panhandle region on Saturday. Meanwhile weak upper level ridge
lingers over IL while high pressure also stays over the southern
Great Lakes region, keeping central and southeast IL dry with
partly to mostly cloudy skies. Highs in the upper 50s and lower
60s again on Saturday.

Cutoff upper level low moves to near Memphis by sunset Sunday and
keeps most of its showers south of IL, though some models have
light qpf as far north as I-64. Partly to mostly cloudy skies
Sunday, with more clouds over sw portions of CWA. Upper level low
moves into northern AL/southern TN river valley Monday and pivots
light moisture nw into KY and southeast parts of MO/IL/IN,
possible getting isolated light showers near Lawrenceville Mon
afternoon. Highs Sunday in the low to mid 60s, and mid to upper
60s on Monday, which is close to normal for late April.

Upper level low moves into the eastern TN river valley Tue while a
northern stream upper level trof/short wave tracks into the upper
Midwest. Our CWA should be in between these two system on Tue and
generally dry conditions monday night and Tue. Highs Tue again in
the mid to upper 60s. The surface and upper level low moves into
northern WI and western Lake Superior Tue night and still appears
to push a band of rain showers se across IL during Tue night and
shifting east of IL during Wed with a bit cooler temps Wed/Thu
with highs in the lower 60s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1152 PM CDT Wed Apr 18 2018

MVFR CIGs will prevail across the central Illinois terminals into
Thursday morning on the back side of an area of low pressure.
Scattered flurries are possible across KPIA, KBMI, and KCMI for
the next few hours, but the remaining local terminals should stay
dry. Gusty northwest winds will prevail into the overnight hours,
but will gradually subside by late tonight. The CIGs should
scatter out from north to south Thursday morning, resulting in VFR
conditions for the balance of the TAF valid time.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from 1 AM to 8 AM CDT Friday for ILZ062-063-
066>068-071>073.

&&

$$

SHORT TERM...07
LONG TERM...07
AVIATION...Bak



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