Area Forecast Discussion
Issued by NWS Central Illinois

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502
FXUS63 KILX 251546
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1046 AM CDT WED MAY 25 2016

.UPDATE...
Issued at 1045 AM CDT Wed May 25 2016

Forecast was updated early this morning to address convection
chances today and will make a few more tweeks to pops today as
coverage has been less this morning over central/eastern IL.
Despite surface dewpoints in the low to mid 60s, ILX 12Z sounding
still showing somewhat of a dry layer above the surface that
appears to be limiting convection over much of CWA. Isolated
showers weakened as the moved toward Peoria area, while Clay
county IL is on northern fringe of area of shower and
thunderstorms extending south across southern IL ginto western KY
and tracking eastward. Clouds have increased over southern and
western parts of CWA at late morning and expect clouds to increase
over remainder of CWA during the afternoon. Still expect chances
of showers and thunderstorms to develop over central IL during
this afternoon, especially mid/late afternoon as airmass gets more
unstable with CAPES rising to 1000-2000 j/kg by 21Z/4 pm with
2000-2400 CAPES from Rushville to Bloomington nw. Bulk Shear is
20-30 kts and highest in western CWA where SPC has marginal risk
of severe by later this afternoon west of I-57. Temps currently
have warmed to 72-78F, south winds 10-15 mph and gusts of 15 to
25 mph to help warm temps into the low to mid 80s this afternoon.

&&

.SHORT TERM...(Today)
ISSUED AT 326 AM CDT Wed May 25 2016

An elongated low pressure region through the northern and central
Plains will be the primary weather-making feature today as it moves
slowly northeastward in southwesterly flow. The upper level pattern
has become more zonal over the past day compared with the blocked
pattern of the past few days which should allow more progression of
convection into central IL. A series of convective complexes from OK
to SD will approach the Mississippi by early morning...although in a
weakening state. Outflows from these systems combined with an upper
level shortwave associated with these features may provide the lift
necessary for thunderstorms to spread into central IL by late
morning and afternoon. Forecast soundings indicate around 1500-2500
J/KG cape resulting from increased moistening and steep mid-level
lapse rates and storms...as well as 0-6 km bulk shear of 25-30 kts.
This could be enough to produce a few strong to severe storms and
SPC has most of central IL west of I-57 in a marginal risk of severe
storms containing strong wind gusts and large hail to 1 inch
diameter.

Warm temperatures will continue today with highs again in the low to
mid 80s. Dewpoints in the mid to upper 60s will make this feel a
touch more humid than yesterday. Southerly winds 10 to 15 mph will
result from a gradient between the low pressure over the Plains and
high pressure over the east coast.

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 326 AM CDT Wed May 25 2016

Not a lot of change from previous thinking on the evolution of the
upper level pattern and associated surface features the next several
days. Upper flow currently coming out of the southwest, rounding the
southern edge of a closed low off the California coast. This feature
will open up and gradually move into the central Plains by Friday
evening, before lifting into the upper Mississippi Valley. As the
main surface reflections remain well to our north and northwest,
precipitation patterns in our area will be driven by subtle waves in
the upper flow, as well as leftover boundaries from earlier
convection. As such, it will be difficult the next few days to pin
down specific periods that will see any extended dry spells.
However, as the holiday weekend progresses, there are indications
that at least the nighttime hours will be dry, and have trended
toward having only slight chance PoP`s at night beginning Saturday
night and continuing into early next week. No real sign on breaking
the extended warm spell, as highs remain in the lower to mid 80s
into early next week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 629 AM CDT Wed May 25 2016

Remnants of overnight convective systems over the central Plains
approaching the Mississippi/lower Missouri Valley regions this
morning and ouflows ahead of these are beginning to trigger
isolated thunderstorms. Still looks like this activity is at least
a few hours away from central IL terminals...although timing of
impacts at any terminals remains uncertain. Have included VCTS
starting at 16-18Z and continuing at 02-03Z to highlight period of
best thunderstorm chances. Primarily VFR cigs/vsbys expected the
next 24 hours however isolated MVFR possible in thunderstorms.
Winds S around 10 kts through the period...with gusts to around 20
kts during the afternoon to early evening.


&&

.ILX Watches/Warnings/Advisories...
NONE.
&&

$$

UPDATE...07
SHORT TERM...Onton
LONG TERM...Geelhart
AVIATION...Onton



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