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Area forecast discussion 
National Weather Service Lincoln Illinois
930 am CDT Tuesday Jun 30 2015

issued at 922 am CDT Tuesday Jun 30 2015

Made some updates to the forecast this morning...mainly to lower
probability of precipitation. Short-wave trough that brought a few showers and
thunderstorms to the area last night is currently pushing into
Indiana. Subsidence on the back side of the wave will lead to dry
conditions for the remainder of the morning into the early
afternoon before an approaching surface trough potentially
triggers a few additional storms this afternoon. Most models
remain fairly dry...with both the hrrr and NAM suggesting the best
areal coverage will likely be across east-central Illinois during
the late afternoon. Have therefore gone with a dry forecast for
the remainder of the morning...with low chance probability of precipitation along/south of
a Rushville to Danville line during the afternoon. Under mostly
sunny skies...temperatures will be a few degrees warmer than
yesterday...with afternoon highs reaching the lower to middle 80s.


Short term...(today)
issued at 333 am CDT Tuesday Jun 30 2015

Low pressure area over lake mich will slowly drift east across the
Great Lakes region today. An associated weak surface trough will rotate
across the area as well. Surface pattern will prevent an increase of low
level moisture from outside the any moisture available for
the surface trough will be from what is already in place or from
evapotranspiration from the fast growing corn/bean fields. Even
though forcing along the front could be weak as well...still think
thunderstorms will develop along the boundary late this morning and
continue through this afternoon. So will maintain chance probability of precipitation across
the area in the forecast. Winds will west west to northwest through
the day partly sunny skies. Afternoon highs should be a degree or
two warmer than yesterday.

Long term...(tonight through monday)
issued at 333 am CDT Tuesday Jun 30 2015

Actually the good news continues in this round of model solutions
for a couple of dry periods this week...particularly in the northern
half of the state. In the shorter term, tonight will see the
dwindling of any activity left over from potential convection this
afternoon, but after midnight the higher probability of precipitation shift to the southwest
as another wave dives almost straight south from the upper Midwest
and down along the middle miss River Valley. Models slow the wave and
continue its impact into tomorrow and tomorrow evening, particularly
in the southern tier of the state. Precipitation almost skirting the
building surface ridge just to the north and keep the probability of precipitation close.
However, Thu-Sat...the models are starting to clear a bit with the
probability of precipitation and put central and northern Illinois in a dry spot with that surface
ridge building. GFS and European model (ecmwf) are both trending drier...even
pushing the Friday shortwave much further to the south...with the European model (ecmwf)
not quite as dry. Have continued to dry out the gridded forecast as
the superblend is still working out its previous guess and dealing with
the wetter European model (ecmwf). Unfortunately at this time, another wave is
showing up for the latter half of the weekend and probability of precipitation returning Sat
night/sun. With a major pattern shift, would not be surprised to
see this shift as well. But for now...starting the drier trend for
the end of the week.


Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 630 am CDT Tuesday Jun 30 2015

VFR conditions will prevail at all sites for most of the period.
Will have some light fog at all sites for couple hours this
morning. Then skies should be scattered with just some cumulus around.
One isolated T-storm will effect Dec for an hour so will have
tempo group for it with thunderstorms in the vicinity for couple of hours otherwise. Hires
models forecast scattered convection over the area for this
afternoon so have thunderstorms in the vicinity with scattered cumulus at all sites starting at
18z...and lasting until around 00z. Scattered clouds will continue
into the evening but then have added chance of fog with clear
skies and lighter winds overnight. Winds will be westerly this
morning and then become northwest this afternoon...and then
northerly this evening.


Ilx watches/warnings/advisories...


short term...auten
long term...hjs

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