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Area forecast discussion 
National Weather Service Lincoln Illinois
1109 PM CDT Tue Sep 23 2014

issued at 838 PM CDT Tuesday Sep 23 2014

High pressure continues to edge slowly away from our area this
evening as a weakening trof west of the Missouri River valley
tracks northeast along with its associated precip shield. Clouds
from the upper wave were edging slowly east into west central
Illinois this evening but the precip will remain well to our west
as some very dry air remains locked in place over the Midwest
thanks to the departing fair weather system. Other than the high
level clouds passing thru the area tonight, not much else
happening weatherwise, so other than the usual early evening
adjustments to the hourly temperatures, no other changes were
made. As a result, no zone forecast product update needed for this evening.


Short term...(tonight)
issued at 238 PM CDT Tuesday Sep 23 2014

Center of high pressure over Ohio early this afternoon. Skies
remaining mostly clear at the moment, although a fairly large shield
of mid and high clouds has edged into far western Illinois. This is
ahead of a storm system centered in south central South Dakota. Much
of the clouds and energy with this system will be tracking to our
northwest, so not much more than an increase in cirrus is expected
for US tonight. Temperatures should be a few degrees warmer tonight,
with more of an east/southeast flow on the back side of the high.
However, some mid 40s are still likely in eastern Illinois, where
the clouds will be less of a factor.


Long term...(wednesday through tuesday)
issued at 238 PM CDT Tuesday Sep 23 2014

The low pressure system churning across South Dakota/Nebraska on
Tuesday will move northeast into the western Great Lakes on
Wednesday. A trailing surface trough will advance across Iowa and north
Missouri, but dissipate as it reaches western Illinois. No rain is
expected in central Illinois from that system, with just residual mid and
high clouds on Wednesday. The additional cloud cover may keep high
temps similar to tuesday's readings in the mid 70s. However, the
warming trend will return for Thursday into Friday as high pressure
builds back across the region in the wake of the dissipating trough.

The upper levels will be dominated by a long wave ridge all through
the rest of this week and into this coming weekend, with various
waves trying to flatten the northern part of the ridge along the
Canadian border. Eventually a low pressure system originating near
the Gulf Coast will be drawn into the ridge toward southern
Illinois. There are large differences between the European model (ecmwf) and the GFS
on the timing of the arrival of that system in Illinois. The 12z
European model (ecmwf) brings the low into the area Monday night and Tuesday, while
the GFS holds off until next week Wednesday. We trended up with the
pops on Tuesday to an area of low chance in the east, just to show a
trend toward rain potential in the forecast for sometime the first
half of next week. We kept just slights elsewhere from Mon night
through tues night.


Aviation...(for the 06z tafs through 06z Wednesday night)
issued at 1104 PM CDT Tuesday Sep 23 2014

VFR conditions expected thru Wednesday night. Broken to overcast
cirrus deck will continue to track across our area during the
night with the lower clouds and precip staying well west of the
taf sites. Surface winds will remain light easterly tonight at
5 kts or less, and then from a southeast direction on Wednesday
with speeds of 10 kts or less.


Ilx watches/warnings/advisories...


short term...geelhart
long term...shimon

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