Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 241729

Area Forecast Discussion
National Weather Service Lincoln IL
1229 PM CDT Fri Mar 24 2017

Issued at 948 AM CDT Fri Mar 24 2017

Main update right now was for the sky trends. Skies largely
clear, but an area of stratocumulus is advecting out of southern
Illinois, and will overspread the southeast CWA. Clouds are also
spreading eastward across Missouri and will move into central
Illinois beginning around midday. Temperatures already reaching
the lower to mid 60s in several areas, and should be on track for
the 70s before the clouds arrive and slow the temperature rise.


.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 18Z TAFS through 18Z Saturday afternoon)
Issued at 1230 PM CDT Fri Mar 24 2017

Concern in the shorter term is with an area of ceilings around
3000 feet streaming northeast out of southern Illinois. Current
trajectories keep the lower ceilings just south of KCMI/KDEC but
these areas will likely see some of the fringes. Ceilings may
briefly drop below 3000 feet there, but cloud heights have been
rising and the probability of this happening that far north is
low. Southerly winds will continue gusting to around 30-35 knots
as good mixing takes place, but will subside toward late afternoon
as the clouds increase over the region.

Longer range, focus remains in the showers and thunderstorms that
will be moving east out of Missouri and Iowa later this evening.
Morning model suite continues to slow the arrival a bit, with
locations around KBMI-KSPI westward seeing some storms arriving
toward 02-03Z and KCMI toward 06Z. Thunderstorms will remain
scattered but not prevailing, so will continue with the VCTS
mention along with prevailing showers. As the rain arrives,
ceilings and visibility will lower to MVFR levels in most areas
after 06Z and continue through the remainder of the forecast




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