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Area forecast discussion 
National Weather Service Lincoln Illinois
343 am CDT Thu Aug 21 2014

Short term...(today and tonight)
issued at 342 am CDT Thursday Aug 21 2014

Warm front has lifted north through most of the area and based on
surface observations, looks to be just north of I-74 at this point.
Believe the front will continue to lift north through the day,
resulting in the whole County Warning Area being in the warm sector for the end of
the week. However, the mid level ridge will be somewhat flat and any
disturbance or wave that moves along the top of the ridge could
result in precip dropping into the northern and northeastern part of
the County Warning Area. So chance pops will continue to be warranted over parts of
the County Warning Area today and tonight. Pops will be less during the daytime
hours but then increase over the northeastern half of the County Warning Area for
the overnight hours, tonight. Temperatures will be warm today, but
cloud cover could keep afternoon highs from getting too high, though
still expecting highs around 90 today. Lows tonight will be similar
to now, just about 1-2 degrees warmer.


Long term...(friday through wednesday)
issued at 342 am CDT Thursday Aug 21 2014

Summer heat continues through the remains of the weekend. Hot and
humid conditions lending to an isolated thunderstorm threat through
the weekend, particularly towards the NE as waves push over the
upper ridge building into the Midwest. Models shifting with each
issuance as to the actual increased threat with the erosion of the
ridging to the NE. Heat and humidity has been more consistent,
though even that has seen some shifts, starting to retract some of
the eastward creep of the 850 mb temps. Not pulling back too much
in the way of guidance just yet and temps Fri-sun still in the 90s,
heat indices over 100f. Issuance of a heat advisory covered
above...however, should the dwpts materialize, or see the temps
respond as expected behind this mornings warm front today... will
rethink the issuance of a heat advisory for the weekend as these
temps are not only well above normal, but more impactful after such
a mild Summer so far. Into the extended, day 6/just into day 8,
models have gone back to a divergence in solutions as the GFS is
more progressive with the next upper trof moving a cold front
through with storms and cooler temps in the wake...while the 00z
European model (ecmwf) is now cutting off the low over the NW, extending the ridges
hold over the region.


Aviation...(for the 06z tafs through 06z Thursday night)
issued at 1110 PM CDT Wednesday Aug 20 2014

Forecast concern remains coverage of early morning convection
along with the potential for fog. Little overall change from
previous thinking with coverage and timing of convection the
main challenge tonight with a small cluster of storms well
south of our taf sites and waiting for another band of storms
to fire along a stalled frontal boundary just to our north
late this evening. Not very confident with respect to the
early morning convection with several of the high res forecast
models suggesting storms to affect mainly the northeast half
of the area with the higher probabilities of storms for pia,
bmi and cmi. Will continue with that thinking for now with
the thunderstorms in the vicinity mainly for our north and east areas and hold off
mentioning any rain for spi and Dec. What storms we do see
fire overnight should be pushing out of the area at or just
after 15z Thursday with forecast soundings continuing to
indicate VFR conditions thereafter.

Will continue to indicate some MVFR vsbys in fog later tonight
for our taf sites, especially in areas that received significant
rainfall today like spi and Dec. What fog we do see develop
overnight should lift by 13z. Light southerly winds will continue
thru the early morning hours and then become south to southwest at
10 to 15 kts during the day on Thu, before diminishing to 5 kts or
less by evening.


Ilx watches/warnings/advisories...


Short term...auten
long term...hjs

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