Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 151045

Area Forecast Discussion
National Weather Service Lincoln IL
545 AM CDT Sat Jul 15 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 316 AM CDT Sat Jul 15 2017

A weak high pressure ridge remains in control of the weather
across Central Illinois this morning. And with slightly drier air
in place, the warm temperatures in the low 80s with plenty of
sunshine and light winds will result in a mild, pleasant day for
Central Illinois. Overnight tonight, the ridge axis shifts to the
east and the winds become increasingly south/southwesterly,
starting a prolonged period of warm air advection into the region
that will bring a warming trend into the work week.

.LONG TERM...(Sunday through Friday)
ISSUED AT 316 AM CDT Sat Jul 15 2017

Sunday will try to start that warming trend, and highs will try to
get into the mid to upper 80s before a weak frontal boundary
moves through the state in the afternoon. The boundary will bring
a threat for some convection in the afternoon hours and into the
evening. The slightly cooler air and associated cloud cover may
keep Monday`s high temps in the low to mid 80s, but will not hang
around long enough to counter the warmer air working into the
midlevels as the warm air trapped under the ridge in the southwest
advects eastward. In the shorter term, the best chances for
precipitation are Sunday afternoon/evening. Then the forecast
dries out a bit as the pattern shifts to a more zonal flow to the
north and a bit of a flat upper ridge over the FA. The ECMWF and
the GFS are a bit conflicted in letting that ridge slide back to
the west somewhat as a more northwesterly flow sets up. A series
of quick waves topping the ridge for the latter half of the week
have resulted in a lot of small pops. How amplified the wave
pattern will very likely control how much precip Central Illinois
will have. Either way, the mid levels maintain a warming trend
throughout...and have continued to bump the temps in the latter
half of the week a degree or two above most guidance...which will
result in heat indices back into the low 100s.


.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 543 AM CDT Sat Jul 15 2017

Not much of a change in the forecast. HRRR still having some
issues with low level moisture in the immediate term. So the
present conditions in the models are already off for the patch of
clouds btwn BMI and CMI. Since the cloud cover is relatively
small...handled with a very short lived tempo. Wind light and
variable and will be eventually be more southerly after midnight




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