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afdilx

Area forecast discussion
National Weather Service Lincoln Illinois
110 PM CDT Wed may 24 2017

Update...
issued at 1059 am CDT Wed may 24 2017

Updated the forecast to remove the fog wording for the morning and
to adjust pops and weather for current trends. An area of fairly
consistent showers remains along and east of I-57 late this
morning. According to radar and satellite trends this should
continue into much of the afternoon as a low level boundary and
areas of low pressure move across western and central in.

Broad cyclonic flow around an upper level low in east central MO
will keep the potential for diurnal showers and isolated T-storms
in much of central Illinois through the afternoon. Aloft, there is a
similar setup to yesterday afternoon with relatively cold
temperatures aloft with the low. Thus, would not be surprised to
see a few more cold air funnels this afternoon and evening. Can't
rule out a landspout near any low level boundaries that form,
although we had a slightly better set up for that yesterday with
a slow moving front...that has since moved well to our east.

&&

Short term...(today and tonight)
issued at 328 am CDT Wed may 24 2017

Deep upper level trough dominates the center of the country this
morning, while a surface low to the east continues to move out of
the region with weak ridging in its wake. An increasing pressure
gradient today will result in some northerly winds...getting
slightly stronger throughout the day to 10-12 mph by this
afternoon. Deep moisture still available under the upper low today
will result in another showery day...with chances increasing into
the afternoon. Cool temperatures will prevail with the northerly
winds and ample cloud cover...and overnight lows will be limited
to the lower 50s/upper 40s as the clouds slowly recede later
Thursday morning. &&

Long term...(thursday through tuesday)
issued at 328 am CDT Wed may 24 2017
skies clearing early Thursday will result in a little warmer
temperatures for central Illinois...even with northwesterly winds. Dry
through Thursday night, although the models are still having some
issue with the weak ridge aloft. The wave/mesoscale convective system system that the
models have been persistent with for Friday night...the 00z GFS
has weakened with the NAM and European model (ecmwf) far more aggressive. More in
line is the system for the weekend...Saturday being another
stormy day as a surface low tracks through the Midwest, and a warm
frontal passage during the day on Saturday. The Holiday weekend
will be warmer...but periodically stormy. Monday has mild
temperatures in the 70s...but again, cyclonic flow aloft with
plenty of moisture in the soundings will likely end up with more
weak convective showers at the very least in the afternoon.

&&

Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 100 PM CDT Wed may 24 2017

Plenty of steady rain and MVFR...and at times IFR...ceilings will
linger in eastern Illinois through much of the afternoon as an upper
level circulation in the Ohio Valley lifts to north- northeast
into southeast Indiana. Partial clearing in the rest of central Illinois
late this morning has resulted in an extensive cumulus field with
VFR ceilings of 3500-4500 feet. Due to the proximity to the upper
level cold pool in the mid Mississippi River and surface temperatures
in the lower to middle 60s, scattered showers are anticipated into
early evening.

Later tonight some partial clearing, along with a wet ground and a
northwest wind of 5-10 kts we can expect stratus to develop at
most of the taf sites in central and eastern Illinois. IFR ceilings are
expected to develop after 09z and continue until 14-15z. The
surface wind should stay high enough to keep widespread low
visibility from forming, but will need to keep an eye on this
particularly in eastern Illinois.

&&

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

$$

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