Area Forecast Discussion
Issued by NWS Central Illinois

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024
FXUS63 KILX 250826
AFDILX

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

.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 06Z TAFS through 06Z Wednesday night)
Issued at 1152 PM CDT Tue May 24 2016

VFR conditions will prevail at all TAF sites remainder of the
night. Then question is will any pcpn reach into the area and if
so, what time. COnvection out in the plains not being handled well
by convective short-term models...which is normal. Models differ
on how to handle the possible incoming pcpn. Newest HRRR model
brings some pcpn toward the sites beginning around 15z. These
seems somewhat plausible so will add a VCTS for all sites
beginning around 15z at SPI and then advecting it eastward,
starting last at CMI around 18z. Since remainder of the afternoon
and into the evening is uncertain, will keep the VCTS going just
until early evening and then have drier weather for remainder of
the TAF period. Will keep VFR conditions throughout. Winds will
light out of the south tonight and then be southerly tomorrow
with some gusts to around 20kts.


&&

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

$$

SHORT TERM...Onton
LONG TERM...Geelhart
AVIATION...Auten



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