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FXUS63 KILX 150716

Area Forecast Discussion
National Weather Service Lincoln IL
216 AM CDT Sun Sep 15 2019

Issued at 201 AM CDT Sun Sep 15 2019

Scattered showers and storms are possible mainly along and north 
of I-72 this morning, dry weather will prevail through the 
afternoon. A few additional isolated showers or storms are 
possible this evening. Dry weather then resumes into the middle of 
the upcoming week as high pressure builds across the region. 
Temperatures will average above normal over the next several days,
with afternoon highs in the upper 80s to around 90. 


.SHORT TERM...(Today and tonight)
ISSUED AT 201 AM CDT Sun Sep 15 2019

Early this morning, low level jet driven storms will continue to 
move east across northern Illinois, but will gradually build south
into central Illinois likely in a decaying or weakening state as 
the LLJ veers and weakens. Storms may be possible as far south as 
the I-72 corridor through mid morning, then coverage should 
diminish. At this time, it appears the threat for severe weather
is fairly low, but will have to monitor a few of the stronger 
storms that could produce large hail.

This afternoon, guidance suggests that the atmosphere will once
again become moderately unstable ahead of an approaching weak
surface trough. There is no notable support aloft, so the trough
will struggle to move into the area and forcing will be weak.
Still, some guidance suggests that a few isolated to widely
scattered storms will be possible late this afternoon or evening.
Very weak shear in place will result in pulse storms, so the
overall severe threat will be low, but could see some locally
strong winds or heavy rain. Most areas will remain dry this


.LONG TERM...(Monday through Saturday)
ISSUED AT 201 AM CDT Sun Sep 15 2019

A strong upper ridge will be in place across the central Great  
Plains to begin the week while an expansive surface high will be 
centered over the Midwest. These features will shift east slowly 
through midweek with the upper ridge becoming centered across the 
local area Tuesday and Wednesday. Dry weather will prevail under 
the influence of the high through the first half of the week, and 
temperatures will be quite warm each day, topping out in the upper
80s to around 90F. Humidity will also return through this time 
frame with dew points in the upper 60s to around 70F. 

Meanwhile, a couple waves moving in from the west coast will bear 
close watching as they approach the local area through the latter 
half of the week. Initial shortwave over northern CA late Monday 
will become more compact as it lifts to the northern Great Plains 
Wednesday. Models have come into much better agreement with the 
motion of this system lifting the system into Ontario on Thursday 
and causing the upper ridge to buckle slightly. An attendant 
surface cold front will push into the Upper Midwest Thursday with 
the tail end of the front pushing towards an unstable air mass in 
place across central Illinois. The local area does remain well 
displaced from the upper level support with weak upper flow and 
shear, while forcing is mainly limited to the low level 
convergence along the front. These limiting factors may help keep
storm coverage limited with diminishing chances overnight, as 
depicted by the ECMWF and GEM. 

A stronger trough is progged to move onshore over the west coast 
Wednesday night moving into the Great Plains late Friday into 
Saturday. This wave is progged to push the upper ridge off to the 
east coast, and could result in more unsettled weather for central 
Illinois next weekend.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1148 PM CDT Sat Sep 14 2019

Scattered thunderstorms are possible late tonight into Sunday
morning, with the highest chances at KPIA and KBMI from 10Z-16Z,
and lower chances for showers at KSPI, KDEC, and KCMI. Additional
thunderstorms are possible for KPIA and KBMI after 23Z, however
low probabilities only warrant VCTS mention at this point. Brief 
isolated MVFR cigs/vsbys and gusty winds are possible in 
thunderstorms, but otherwise, VFR conditions are expected with 
increasing high and mid level clouds through tonight. Winds S 
around 10 kts through tonight, then becoming SW 10-14 kts with 
gusts 15-20 kts after 16Z.




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