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Area forecast discussion 
National Weather Service Lincoln Illinois
1158 PM CDT Sat Sep 20 2014

issued at 909 PM CDT Sat Sep 20 2014

Line of thunderstorms from around Beardstown through Bloomington
sinking slowly southward ahead of cold front approaching central
Illinois from the northwest. Current forecasts look good with respect to
thunderstorm coverage from this line and ending time and no
updates planned for pops at this time. Cold frontal passage by
morning will lower high temperatures 10 degrees or more for Sunday
but overnight steady light southwest winds will veer to northwest
with mixing keeping temperatures from dropping dramatically. Only
updates at this time will be for recent temperature/humidity/wind


Short term...(tonight)
issued at 300 PM CDT Sat Sep 20 2014

Showers and thunderstorms continue to develop along and NW of a
Chicago to Peoria to Quincy line ahead of a cold front over central
Iowa. Storm Prediction Center has slight risk of severe storms NW of I-70 from mid
afternoon into mid evening with 15% risk of damaging wind gusts and
large hail along with 2% risk of tornadoes. Breezy SW winds have
brought in moist dewpoints in the mid 60s to near 70f while
temperatures have warmed into the lower 80s. Atmosphere has become
unstable with convective available potential energy of 1500-2500 j/kg and could get as high as
2500-3000 j/kg from Springfield WSW late this afternoon and early
evening. Bulk shear of 35-40 kts from Lincoln northward to combine
with unstable airmass to support slight risk of severe storms. Cold
front to push se across central Illinois tonight and move into southeast
Illinois early Sunday morning. Will continue higher chances of showers and
thunderstorms tonight and gradually lower pops over central Illinois from
the NW later this evening and overnight as cold front passes by.
Lows tonight to range from the upper 50s NW over Illinois River valley, to
the mid 60s in southeast Illinois.


Long term...(sunday through saturday)
issued at 300 PM CDT Sat Sep 20 2014

Quiet weather pattern expected thru most of the extended period as
the deep upper trof that brings the cool weather to start the work
week shifts off to the northeast as upper level ridging builds over
the center of the nation. Upper trof the moves into the western U.S.
Later tonight and Sunday slowly shifts east across the Central Plains
with its associated precip shield. However, as it moves east of the
Missouri River valley Wednesday, longer range models continue to
amplify the ridge over the central portion of the country. The large
surface high pressure area that brought the cool weather early in
the period will have quite a bit of dry air associated with it so
most models show a decrease in precip coverage to our west as the
weakening trof approaches our area late in the week. As a result, will
continue to keep precip out of the extended forecast with a gradual
warming trend during the second half of the week where temperatures
will actually be above normal starting on Thursday.


Aviation...(for the 06z tafs through 06z Sunday night)
issued at 1158 PM CDT Sat Sep 20 2014

Line of scattered thunderstorms and rain from around ktaz-kdnv to shift southward across
central/southeast Illinois overnight producing isolated MVFR cigs/vsby
until 12z...however all activity is past central Illinois taf sites and
no thunderstorm activity to re-develop overnight. Some light fog
possible, however steady SW-west winds continuing overnight likely to
prevent significant visibility reductions so have kept mention of
fog in VFR category. Cold front to approach kpia from the
northwest by 09z and sweep across central Illinois by 12-15z. Expect a
wind shift from west/SW to northwest as well as development of scattered
cloud cover around 3-5 kft above ground level. Northwest winds 13-17 kts with gusts
20-25 kts developing late Sunday morning. Increasing cloud cover
likely producing areas MVFR ceilings from kpia-kdec-kprg
northward after 16z but only slight chances rain showers with little
visibility reduction.


Ilx watches/warnings/advisories...


short term...07
long term...Smith

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