Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 212330
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
630 PM CDT WED SEP 21 2016

.SHORT TERM...(This evening through Thursday)
ISSUED AT 250 PM CDT Wed Sep 21 2016

Second round of convection across the northern CWA this afternoon
pulsed up toward severe levels earlier, but has been diminishing as
of late with the outflow heading further south. The boundary has had
a bit of punch though, with estimated 60 mph winds north of
Galesburg and a 44 mph gust at the Peoria airport as it passed those
locations. Trailing edge of the outflow extends northwestward all
the way into north central Iowa, where some new development is
taking place, and the main threat of strong/severe storms this
evening will be west of the Mississippi River. Will maintain a dry
forecast for tonight across our area. Coolest conditions tonight
again expected east of I-57 where lows will be in the lower 60s, but
near 65 degrees further west.

Upper ridge will continue to hold firm on Thursday and keep the
convection closer to a warm frontal boundary from southern Minnesota
into Wisconsin. With no real change in air mass, highs once again
should be close to 90 degrees tomorrow.

.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 250 PM CDT Wed Sep 21 2016

Upper air this morning shows plume of low level moisture from TX
to OK into IA. Aloft, upper ridge axis from central TX into southern
IA. Band of moderately fast upper winds across top of ridge over
Dakotas and MN seen in moisture channel and weak difluence
farther south over WI to northern IL has aided to support the
morning MCS convection that pushed surface boundary through north
and into central IL by afternoon. Main focus for storm development
still should be over IA to MN overnight with only some light
lingering pcpn in northern this evening. Mainly dry in CWA.

Ridge builds some in models Thursday into Saturday with warm
conditions. Models in good agreement on the ridge and the dry,
warming conditions. Then with the timing of the main front and upper
trof for the weekend, they start to diverge. EUR still a bit slower
than GFS on the movement of frontal system and EUR slower on the
upper low development. Result is to keep chance pops and cooler
temps on Monday into Tuesday night. As get closer, further
refinement of pops will be possible. In any event, it will be a
change early next week from the warm conditions this week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 630 PM CDT Wed Sep 21 2016

VFR conditions expected the next 24 hours as high pressure ridge
axis continues to extend westward into central IL, while a frontal
boundary associated with periods of thunderstorm development
remains off to the northwest from the central Plains to the upper
Midwest. A weakening outflow boundary from thunderstorms over
northern IL earlier today will be a focus for slightly gusty and
shifting winds this evening and looks to affect KDEC and KCMI.
north of the boundary winds NE 10g15 kts while south of the
boundary generally SE 5-10 kts. The boundary looks to continue
weakening and slowing through around 03Z. Overnight...winds
generally becoming SE 4-8 kts, then winds turning southerly and
increasing to 7-10 kts after 14Z.

&&

.ILX Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...Geelhart
LONG TERM...Goetsch
AVIATION...Onton



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