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Area forecast discussion
National Weather Service Lincoln Illinois
1147 PM CST Wed Nov 13 2019

issued at 250 PM CST Wed Nov 13 2019

Southerly winds today brought slightly warmer air into central
Illinois, with afternoon highs approaching 30. Another front will
be moving through the state late tonight, shifting the winds to
the northwest for Thursday. A brief chance for some very light
snow this evening will be the case over areas north of a Macomb
to Bloomington line. Otherwise, conditions will be dry for
Thursday into Friday with slowing warming temperatures through the


issued at 847 PM CST Wed Nov 13 2019

A band of frontogenetic forcing will push across the northern half
of Illinois this evening. However, snowfall will be limited due to
a dry sub-cloud layer, as well as most of the forcing for precip
residing above 750 mb. That will result in mainly a thick mid-
cloud layer, with a few flurries possible. No measurable snow is
expected in our County Warning Area from this disturbance. A cold front will
eventually progress across Illinois late tonight through Thursday
morning. That frontal passage will be dry, with a wind shift from SW to northwest
being the primary result. The air mass behind that front will
actually not be all that cold either, as we see high temps reach
slightly warmer than Wednesday.

Little to no changes were needed to the forecast database this
evening. Adjusted wind gusts down slightly, as most areas have
stopped reporting gusts over 10kt.


Short term...(this evening through thursday)
issued at 300 PM CST Wed Nov 13 2019

Satellite and radar shows the shortwave over eastern NE and
western Iowa moving eastward. This trend is expected to continue
overnight, with the system causing enough lift for some very light
snow over the northern areas of central Illinois. Slight chance probability of precipitation
have been added to the evening hours as a result. Surface data
continues to show frontal wind shift by late tonight over area,
coming through dry with clouds the only impact. High pressure to
be in control on Thursday.

Long term...(thursday night through wednesday)
issued at 300 PM CST Wed Nov 13 2019

Dry conditions and light pressure to be the rule on Thursday
night into Friday. Upper ridge builds into area to help modify
airmass some.

Next system is another front on Sunday, but the moisture is
limited and so it will come through dry, with the only pcpn in the
region over northern IL, north of forecast area.


Aviation...(for the 06z tafs through 06z Thursday night)
issued at 1146 PM CST Wed Nov 13 2019

A weak shortwave passing across northern Illinois late this
evening has caused an increase and thickening of the mid-clouds
across the area. Scattered flurries are likely occurring under the
30+ dbz radar returns, based on upstream reports. The best forcing
for precip will skirt our northern counties, north of Peoria.
While a few flurries could drop out of any mid-level clouds
overnight, no impact to aviation is expected from that
precipitation at any of our terminal sites.

Wind speeds have weakened below 10kt across the board, and should
remain that way over the next 24 hours. A cold frontal passage is forecast
for late tonight and Thursday morning, causing a wind shift from
SW to northwest between 10z (pia) and 17z (cmi).

MVFR clouds are forecast by the hrrr, rap and NAM guidance for
tomorrow morning into afternoon. Have included a period of ovc025
at all terminals at some point tomorrow. Clearing is likely by the
end of the afternoon at all taf sites.


Ilx watches/warnings/advisories...



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