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Area forecast discussion 
National Weather Service Lincoln Illinois
247 PM CST Wed Dec 17 2014

Short term...(tonight)
issued at 245 PM CST Wednesday Dec 17 2014

19z/1pm satellite imagery continues to show overcast conditions
across much of central illinois: however, the clouds are beginning
to erode northwest of the Illinois River. While hrrr guidance has
not been particularly useful in the short-term, satellite trends
suggest skies will partially clear across all but the far east/NE kilx
County Warning Area by early evening. After a period of mostly clear skies early
tonight, clouds will once again begin increasing in advance of the
next storm system, which is currently evident on water vapor imagery
over West Texas. Quite a bit of precip and even some thunder is
occurring ahead of this wave over Oklahoma/texas: however, it is
expected to weaken as it lifts northeastward into the region on
Thursday. It will also be coming into a dry airmass beneath a
prevailing surface ridge axis. Forecast soundings show gradual
moistening from the top-down later tonight, but the lowest levels
below 850mb will remain quite dry through 12z. As a result, have
maintained a dry forecast through the overnight hours. Due to the
initially clear skies and low dewpoints, have gone a couple of
degrees below mav guidance for lows tonight, with readings dropping
into the teens and lower 20s.


Long term...(thursday through wednesday)
issued at 245 PM CST Wednesday Dec 17 2014

Upper flow will be zonal for next few days, with weak waves moving
east through flow. Moisture channel data and upper air shows initial
wave to affect region over nm this morning. This system to
continue tracking to the northeast, pushing some overrunning pcpn
into MO and southern 1/2 of Illinois for late tonight into Thursday. Weak
vort lobe and isentropic lift to be enough to move the light snow
into southern 1/2 of County Warning Area in the morning, but wave moving fast enough
to only affect the morning. Mainly less than half inch.

Next wave to move into region for Friday night and Saturday morning
and the area of lift with this one is farther south, mainly over
southeast cwa. Again, some light snow possible.

Upper flow starts to change on late in weekend and by Monday, flow
is northwest. Digging upper trough over Great Lakes with upper low
closing off by Monday night. This will bring some initial pcpn into
the region ahead of cold front that moves through Tuesday.
Temperatures however, are only cold enough for possible mixture
until Post frontal on Tuesday night and Wednesday. Therefore no snow
accumulation. However by tues night to Wed, only minor vort lobes
rotating around the closed upper low in the cold air, so chance of
light snow accumulations only.


Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 1203 PM CST Wednesday Dec 17 2014

MVFR ceilings will prevail at the central Illinois terminals for
the next few hours before clearing gradually develops from west to
east across the area. 1730z visible satellite imagery shows
clearing beginning to work into the northwest kilx County Warning Area around
Galesburg, and based on timing tools, this should reach kpia by
around 21/22z. Will continue to monitor satellite to see if clouds
can erode faster, but for now will remain pessimistic. Clouds will
hold firm further east at kcmi until early evening when forecast
soundings finally Show Low-level drying. After a brief period of
mostly clear skies tonight, the next approaching system will
spread clouds back into the area on Thursday. Forecast soundings
suggest VFR ceilings developing across central Illinois between 11z
and 14z. May see enough moistening of the profile to produce light
snow at kspi after 15z, but dry conditions should prevail


Ilx watches/warnings/advisories...


Short term...Barnes
long term...goetsch

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