NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION. Privacy and Cookie policy

FXUS63 KILX 282007 AFDILX

Area Forecast Discussion National Weather Service Lincoln IL 207 PM CST Tue Nov 28 2023

SYNOPSIS
Issued at 207 PM CST Tue Nov 28 2023

Cold air tonight will be replaced by more seasonable temperatures on Wednesday. Dry weather will persist across the region into Thursday morning, before a weather system moving in from the southwest brings widespread rainfall for Thursday afternoon into Friday morning.

DISCUSSION
Issued at 207 PM CST Tue Nov 28 2023

Key Messages:

* Unseasonably cold temperatures tonight moderate on Wednesday, then remain seasonable through the weekend.

* A weather system will bring widespread rain Thursday afternoon into Friday morning.

Latest surface analysis indicated a ridge axis stretched from the lower Mississippi River Valley north into the Great Lakes, and a trough to the west over the eastern Plains. The trough will shift east across the area later tonight, initially turning winds southerly, then southwesterly by morning. A dry column will allow for only scattered mid/high level clouds as the system passes. We expect lows to be reached this evening with a quick temp fall into the teens/low 20s (lowest in snow covered areas)
before low level warm advection causes readings to steady out then rise after midnight.

Temperatures moderate on Wednesday as the southwest low level flow continues and mid level flow backs to a more zonal orientation by afternoon. This should boost highs closer to seasonable levels, around 40F north to 50F south.

Thursday, a southern stream shortwave begins to lift northeast from the four corners area, resulting in broad warm/moist advection downstream across the Midwest. Latest guidance spreads likely PoPs northeast across much of southern and central IL during the afternoon. This rain appears to be light initially, then a marked increase in intensity and coverage is expected evening/overnight when a coupled upper level jet shifts overhead.
Thanks to an open Gulf, PWATs peak just shy of 1" across the southern CWA. Mid level lapse rates also steepen during the window of peak lift during the evening, so heavier convective showers are likely at times. Much of the rain will be diminishing Friday morning, with the blended guidance showing around a quarter inch QPF northwest of the IL River, to 1-1.25" south of I-72. Ensemble guidance is showing highest probabilities (50%) of greater than 1" south of I-70, so there is still uncertainty in amounts at this range. However, even if higher end totals are realized we aren't expecting any water issues as recent trends have been dry in these areas - latest drought monitor showing moderate drought south of Shelbyville to Paris line. While not acknowledged in the gridded forecast, we'll need to watch for a potential changeover to wet snow on the northern edge of the precip shield Friday morning, where a few guidance sources show thermal profiles marginally supportive of snow over the northern third of the state.

Behind this system, upper level flow remains active, and deterministic guidance shows a couple shortwaves rippling through the flow Saturday night through Monday. Blended guidance shows low chance (20-30%) PoPs during this period which seem reasonable at this range. Temperatures look seasonable during this stretch, favoring rain as the dominant P-type.

25

AVIATION
(For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1111 AM CST Tue Nov 28 2023

VFR skies this forecast cycle. A surface trough will cross the region tonight, causing winds to back south ahead of it this evening, then veer southwest around 12z. A brief period of marginal low level wind shear exists from around 06-09z, when southwest winds at 2k feet increase to 35-40 kt. Due to the brief window and falling short of criteria have kept this out of TAFs but will monitor for later forecasts.

25

ILX WATCHES/WARNINGS/ADVISORIES
None.

toggle option: (graph/table)

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Central Illinois, IL,