Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 240839

Area Forecast Discussion
National Weather Service Lincoln IL
339 AM CDT Fri Mar 24 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 339 AM CDT Fri Mar 24 2017

A warm front will lift north through Illinois today, setting the
stage for continued significant warm air advection. A strong low
level jet from the southwest at 50 kts has helped keep air temps on
a slow rise all night. Filtered sunshine this morning will aid in
boosting temperatures quickly into the 60s, with high temps topping
out between 70 and 76 degrees. Thickening clouds in our southeast
counties will likely limit highs closer to 70, depending on how
quickly those clouds develop and/or arrive. Our W and NW counties
should see just thin cirrus for most of the day, allowing warmer
conditions to develop there.

Showers and storms will develop in Iowa and Missouri this afternoon,
reaching into our far W counties between 4 pm and 6 pm. So clouds
will be on the increase later in the day there, but high temps
should be realized before those clouds become a factor.

Rain and scattered storms will expand eastward across Illinois this
evening, as low pressure progresses from Oklahoma into Missouri. The
rain should be affecting all of our counties by sunrise on Saturday.
The blanket of clouds and precip should keep lows in the mid to
upper 50s.

While thunderstorms will be possible today and tonight, instability
parameters look marginal and no severe storms should develop.


.LONG TERM...(Saturday through Thursday)
ISSUED AT 339 AM CDT Fri Mar 24 2017

A 547 dm 500 mb low currently deepening over southeast CO early this
morning is forecast to track toward Tulsa, OK by 06Z/1 am Fri night
and into east central MO by sunset Sat, then into central IL Sunday
morning as it gradually weakens. Widespread showers and isolated to
scattered thunderstorms to occur Sat and Sat evening over CWA
ahead of this approaching storm system. SPC continues marginal
risk of severe storms from Jacksonville to Olney sw Sat afternoon
and early Sat evening. Highs Sat still fairly mild in the mid to
upper 60s, except lower 60s far northern CWA by Galesburg and
Henry. Still a good chance of showers overnight Sat night into
Sunday, though diminishing from the w and sw Sunday afternoon as
weakening storm system moves toward southern Lake MI by sunset
Sunday. Lows Sat night in the upper 40s and lower 50s with
Lawrenceville near 55F. A bit cooler highs Sunday around 60F
northern CWA to the mid 60s southeast of I-70.

Most of Sunday night will be dry expect for a 20-40% chance of
showers later Sunday night from Canton and Springfield sw as another
upper level trof off the West Coast moves into the Ozarks by dawn
Mon. The feature shifts east across the mid MS river valley by
sunset Monday, and over the Ohio river valley overnight Monday
night. This will likely spread more showers across the area Monday
and Mon evening, with isolated thunderstorms along and south of
I- 72. Lows Sunday night of 45-50F, then highs Monday ranging from
upper 50s to near 60F nw of the IL river, to around 70F in
southeast IL.

Dry weather will return to central and southeast IL from Tuesday
through Wednesday as surface high pressure ridge builds southward
across the western great lakes and toward central IL. Highs in the
upper 50s and lower 60s Tue/Wed with Lawrenceville near 65F.

Yet another cutoff upper level low/trof to form near the 4 corners
on Tue and eject into the Ozarks by sunset Thu. 00Z Mar 24 models
have trended slower with returning qpf into central IL overnight Wed
night into Thu and likely continues showers Thu night and even into
part of Friday of next week as low pressure eject ne into southern
lower MI and nw Ohio by sunset Fri. Highs Thu around 60F northern
CWA and mid to upper 60s in southeast IL. Temps cool a few degrees
on next Friday with highs of 58-65F, mildest in southeast IL.

CPC`s 8-14 day outlook for Mar 31 - Apr 6, continues to trend above
normal temperatures (50=55%) for central IL and above normal
precipitation (45-50%).


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1100 PM CDT Thu Mar 23 2017

LLWS continues to be the main concern thru about 13z Friday, and
then timing of MVFR cigs from south to north later tomorrow
morning and into the afternoon hours a secondary concern. Wind
profiler at ILX showing south winds of 55 to 65 kts at around
2000 feet AGL late this evening and expect the winds to turn
more into a south-southwest (190-220 degrees) direction during
the early morning hours with speeds holding around 50 kts. As
temperatures start to warm up tomorrow morning, some of the
stronger winds may mix to the surface during the mid and late
morning hours and continue thru the afternoon. The southeast winds
of tonight at 12 to 17 kts with gusts around 23 kts at times will
veer into the south during the early morning hours and then pick
up in speed during the day on Friday with sustained winds of 15 to
20 kts with gusts to around 28 kts at times thru the mid afternoon
hours before we start to see a diminishing trend as we head towards

Timing of the MVFR cigs from south to north later tomorrow morning
into the afternoon hours is a bit more of a challenge as the
lower clouds have not yet developed to our south. They are forecast
to develop after 08z south of the Ohio River and track north and
affect areas roughly along and east of I-55 by mid afternoon.
Confidence on that scenario working out not that high at this
time so will continue with the previous forecast in bringing in at
least low VFR cigs further west and northwest to SPI and PIA by
mid afternoon, while the TAF sites to the east will see the lower
cigs move in during the early afternoon hours. Rain chances and
MVFR to occasionally IFR cigs look to hold off until after 00z
Saturday as low pressure tracks slowly towards central IL.




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