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Area forecast discussion 
National Weather Service Lincoln Illinois
706 PM CDT Monday Aug 31 2015

Short term...(tonight)
issued at 249 PM CDT Monday Aug 31 2015

Weak remnants of a boundary draped over the south and a small surface
low over Indiana are dominating the weather this afternoon for
central Illinois. Yesterday the 70 degree dewpoints were confined
to right along the surface boundary. Today, they are a little more
widespread, even this late in the day as mixing out has been limited
in the almost stagnant airmass. Some observation in the southeast are
actually dropping into the upper 60s after some weak convective
storms this morning. However, quite likely going to see those
dewpoints rebound quickly due to a lot of quantitative precipitation forecast/moisture in the soil.
With light southerly winds and very little in the way of cloud cover
expected tonight, fog is once again the biggest concern. With some
mixing still to come, have left the forecast as patchy for the
entire County Warning Area tonight.

Long term...(tuesday through monday)
issued at 249 PM CDT Monday Aug 31 2015

Main weather story through the extended remains the very warm and
humid conditions that are expected to persist through the week and
into the weekend. High temperatures on Tuesday will reach the upper
80s to around 90 degrees...then readings will climb into the lower
90s for the remainder of the period. Dry weather will generally be
the rule...however isolated convection cannot be ruled
out...especially Tuesday afternoon as a weakness in the mean 500mb
ridge axis remains in the vicinity. Models continue to show some
convection across the eastern parts of the County Warning Area as this feature
gradually shifts into the Great Lakes by Wednesday.

The next significant chance for rain will not arrive until early
next week...when a strong short-wave flattens the upper ridge and
pushes a cold front into the region. Models are in disagreement
concerning the front...with the GFS now trending slower with the
cold front passing through central Illinois late Monday night into
Tuesday...while the European model (ecmwf)/Gem does not bring the cold through the
County Warning Area at all and keeps the ridge strong over the area. Given
persistent and highly amplified ridge positioned across the
Midwest...think a slower break down to the pattern is still best
solution. Have therefore trended slower. As a result...am
expecting dry conditions through Sunday night...with rain chances
arriving in the northwest Monday.

&&

Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 700 PM CDT Monday Aug 31 2015

Isolated showers and storms have remained clear of the terminal
sites, with the closest ones near pia and bmi. Will continue with
a dry forecast for the first couple hours of the 00z tafs since
convection is expected to dissipate quickly with the approach of
sunset, and the ongoing storms are moving very slowly.

MVFR/IFR fog redevelopment appears likely, but coverage of any
dense fog will be more localized. Will continue with the tempos
for IFR fog late tonight.

Winds will continue out of the south tonight, with speeds in the
5-7kt range. As weak high pressure slides farther east of Illinois
tomorrow, winds will become more southwest at 10kt or less.




&&

Ilx watches/warnings/advisories...
none.
&&

$$

Short term...hjs
long term...auten
aviation...shimon

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