Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 210823
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
323 AM CDT Fri Apr 21 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 323 AM CDT Fri Apr 21 2017

08z/2am surface map shows 1008mb low over Lake Huron...with cold
front trailing southwestward through the Ohio River Valley into the
Southern Plains.  High pressure is building southward from Canada
behind the departing front, providing partly to mostly clear skies
across the KILX CWA early this morning.  Aloft...a short-wave trough
over Colorado will track into the Plains today, helping a surface
low develop along the trailing end of the boundary.  As this low
tracks eastward, it will spread clouds and a few showers northward
into portions of central Illinois later today into tonight.  Models
differ on exactly how far north into the drier airmass the precip
will be able to spread: however, consensus continues to suggest only
the southern half of the CWA will be impacted.  Will bring PoPs as
far north as a Paris to Taylorville line this afternoon...with dry
weather expected further north.  Due to increasing mid/high clouds
and a cool northerly breeze, high temperatures will be held in the
upper 50s to around 60 degrees today.  As the low gets closer,
showers will spread further north tonight: however, given the dry
low-level inflow from the N/NE do not think precip will make much
additional progress northward.  As a result, have confined rain
chances to locations along/south of a Rushville to Danville line
tonight.

&&

.LONG TERM...(Saturday through Thursday)
ISSUED AT 323 AM CDT Fri Apr 21 2017

Showers will continue across the southern half of the CWA through
Saturday before gradually coming to an end Saturday night.  Once the
wave passes by to the south, high pressure will bring a return to
mostly sunny and dry weather by Sunday and Monday.  As a result,
temperatures will recover from chilly highs in the middle to upper
50s on Saturday to the lower 70s by Monday.

Zonal flow will dominate the CONUS through the middle of next week
before significant troughing develops over the Rockies/Western
Plains and induces downstream ridging east of the Mississippi River.
A weak cold front will sink southward and become stationary across
south-central Illinois on Tuesday: however, deep-layer moisture will
be limited...so am only expecting a few scattered showers.  As the
western CONUS upper trough digs, the front will get pushed back
northward Wednesday night into Thursday.  Given increasing
southwesterly flow at all levels and much better moisture return from
the Gulf of Mexico, think rain chances will increase markedly.  GFS
MUCAPE suggests thunder will be possible as the boundary lifts
northward through the area as well.  After that, model consistency
remains average to slightly below average for the end of the
period...as the western trough slowly pivots eastward.  There are
still plenty of questions regarding its timing and its associated
surface features: however, it seems highly probable that the end of
next week will be very warm and unsettled.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1249 AM CDT Fri Apr 21 2017

VFR conditions will prevail through the entire 06z TAF period. A
band of low VFR clouds with bases around 3500ft is currently
sinking southward through north-central Illinois. Models are not
handling this cloud area well at all, but based on satellite
trends...it appears it will impact all of the central Illinois
terminals over the next couple of hours. Have timed it southward
through KSPI/KDEC by 10z. After that, mainly high/thin cloudiness
will be noted through the morning...before a mid-level cloud deck
around 15000ft spreads as far north as KSPI/KDEC this afternoon
into tonight. Winds will initially be N/NW at around 10kt
overnight, then will become N/NE Friday afternoon and evening.


&&

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

$$

SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Barnes


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