Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kilx 230112 

Area forecast discussion
National Weather Service Lincoln Illinois
812 PM CDT Mon Jul 22 2019

issued at 812 PM CDT Mon Jul 22 2019

Diurnal cumulus has largely faded, and the earlier more extensive
cloud cover in the southeast County Warning Area has also exited. Much drier air
continues to spread southward, with an 8 PM dew Point of 49 at
Champaign and Rantoul and upper 50s as far south as I-70. Eastern
Illinois, in the driest air, still on track to fall into the mid
50s overnight, with upper 50s across the west.

Forecast is generally on target, though a zone update was issued
to remove the clouds in the southeast County Warning Area.


Short term...(this evening through tuesday)
issued at 229 PM CDT Mon Jul 22 2019

The last few remnants of showers are hanging on early this
afternoon across the far southeastern counties in the County Warning Area south
of I-70, associated with an MCV, though these should end over the
next couple hours. Meanwhile, expansive area of high pressure
over the Great Plains is resulting in northeast winds across the
Midwest. This has been gradually advecting lower dewpoints into
central Illinois, a trend which should continue tonight and into
the day tomorrow as dew points bottom out in the 50s. Temperatures
also remain much less hot compared to the recent stretch, topping
out below normal near 80 today and will do so again tomorrow. The
only real concern in the near term forecast is a very small
chance for an isolated pop-up shower or storm Tuesday late
afternoon/evening. A shortwave trough is progged to dig across the
Midwest, clipping the local area Tuesday evening. A few hundred
j/kg MLCAPE will be in place during the late afternoon. The best
forcing is focused east of the local County Warning Area and only catches the tail
end of the best diurnal instability. For now just covering this
possibility with some "silent 14" pops but will need to keep an
eye on the possibility for some isolated convection during this
time frame.

Long term...(tuesday night through monday)
issued at 229 PM CDT Mon Jul 22 2019

A very quiet stretch of weather is expected through the long term
forecast period, dominated by high pressure over the region
through the end of the week. High pressure over the Great Plains
today will shift to the Midwest on Wednesday then across the
Appalachians Thursday and Friday. Ridging will continue to extend
west-southwest across the lower Mississippi Valley into Texas late in the
week which will cut off moisture return until at least the
weekend. With this in mind, dry conditions will prevail through
the remainder of the week, with a gradual warming trend as surface
ridge axis moves across the local area midweek and southwest flow
begins to allow warmer air back into the region.

Hot and humid conditions may begin to overspread the region by the
weekend. Guidance indicate 850mb thermal ridge of around 19-20c
will flop back over portions of the Midwest this weekend. While
don't anticipate conditions quite as hot as the recent stretch of
heat, widespread 90s do appear possible again this weekend. In
addition, dew points will creep back up into the upper 60s,
possibly higher. Early next week, low pressure is progged to move
east across the Canadian prairies while a trailing cold front sags
south across the Midwest and may linger over the region bringing
a return of more active weather to the area.


Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 622 PM CDT Mon Jul 22 2019

The frontal boundary has pushed out of Illinois, allowing for high
pressure to begin building across central Illinois. This trend
will continue overnight into Tuesday, keeping VFR conditions at
all sites throughout the taf period. The only impact will be winds
through 04z, as northerly winds upwards of 10kts, with some
isolated gusts to 15kts, will be possible. Winds will increase
again Tuesday morning as diurnal heating begins, however skies are
expected to remain mostly sunny as the high spreads.


Ilx watches/warnings/advisories...


National Weather Service Glossary of Abbreviations