Area Forecast Discussion
Issued by NWS Central Illinois

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884
FXUS63 KILX 221202
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
702 AM CDT Sun Sep 22 2019

.SYNOPSIS...
Issued at 355 AM CDT Sun Sep 22 2019

Bands of showers and some thunderstorms will continue to spread
across central IL during today, with a flash flood watch over the
IL river valley into this evening. A cold front will push through
the area during tonight, with showers and thunderstorms diminishing
later this evening and overnight as cooler and less humid air
arrives on Monday.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 355 AM CDT Sun Sep 22 2019

Continued the flash flood watch for the IL river valley through 1
am cdt tonight. Widespread showers and some embedded thunderstorms
to bring an additional 1.5-2 inches of rain today into mid evening
with locally around 3 inch amounts possible. Already a widespread
1-3 inch rain has fallen since Friday morning along and nw of the
IL river with locally 4-6 inch amounts.

Scattered rain showers continue to skirt northern/nw CWA early
this morning and they lift ne. Areas from I-55 southeast have seen
little if any rainfall during the night. More widespread showers
and some thunderstorms were moving ne into parts of Schuyler,
Fulton and Knox counties with widespread convection over central
and eastern IA into nw MO. This moisture is in part due to
remnants of Imelda and supported by very high precipitable water
values of 1.6 to 2 inches, highest over northern/nw CWA. Surface
map early this morning shows a cold front over nw parts of WI/IA
into central KS, to 1006 mb low pressure along the southern CO/KS
border.

Latest CAMs have low pressure ejecting ne along the front into nw
IL by late afternoon while pushing a widespread band of showers
and some thunderstorms eastward across the IL river valley during
this morning and into eastern/se IL during this afternoon and
early evening. Areas se of I-70 will likely stay dry much of today
and also have warmer highs in the mid to upper 80s. Widespread
clouds and showers to keep cooler highs in the mid to upper 70s nw
of I-55. Breezy sw winds will develop today with gusts of 20 to 30
mph expected. In addition to heavy rain threat over the IL river
valley today, SPC day1 outlook has marginal risk of severe
thunderstorms over much of CWA from I-70 nw and se of Galesburg
this afternoon and early evening with 5% risk of hail and damaging
winds.

A cold front is projected to track se toward the IL river by
03Z/10 pm this evening and into southeast IL by 09Z/4 am
overnight. Showers and thunderstorms move into southeast IL this
evening, and then diminish from nw to se behind the cold front
late this evening and overnight. The cold front will pass se of
CWA by dawn Monday with dry and less humid air ushering into the
area. Lows overnight to range from the mid 50s nw of the IL river,
to the mid 60s far se IL by Lawrenceville.

.LONG TERM...(Monday through Saturday)
ISSUED AT 355 AM CDT Sun Sep 22 2019

Weak high pressure settles into MO/IL by Monday afternoon and
brings return of more sunshine and less humid air with dewpoints
in the 50s. Highs Monday in the mid to upper 70s which is closer
to normal for late September. Lows Mon night mostly in the mid
50s. High pressure settles over the mid MS valley and into KY/TN
on Tue and brings another nice day to central/se IL. Skies become
partly sunny by Tue afternoon with highs in the upper 70s in
central IL and near 80F in southeast IL. Dewpoints in the upper
50s to around 60 on Tuesday so fairly comfortable humidity levels
yet.

Next wx system to move into the area overnight Tue night with
surface low passing north of Lake Superior and a frontal boundary
moving into nw IL late Tue night. Have chances of showers and
thunderstorms over central and especially western CWA. SPC day3
has marginal risk of severe storms overnight Tue night nw of I-55
while slight risk is over large part of IA and western WI. Cold
front to push se thru CWA on Wed and bring chances of showers and
thunderstorms, then diminish from nw to se during Wed night.
Cooler and less humid air returns again by Thu with weak high
pressure settling over the area by Thu morning.

Another wx system moves into the upper Midwest late Thu night and
Friday with best chances of convection to our nw while keeping
20-30% pops over central IL and drier in southeast IL late this
week. Temperatures and humidity levels expected to increase Friday
into the weekend with highs back into the 80s and dewpoints rising
into the upper 60s/lower 70s. CPC 8-14 day outlook for Sep 29-Oct
5 has greater than 80% chance of above normal temperatures over IL
so summerlike weather may hang around another week as a
subtropical ridge builds across the southern plains and southeast
states and into the mid MS river valley by early next week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 702 AM CDT Sun Sep 22 2019

The main area of showers and thunderstorms ahead of an approaching
cold front should reach the I-55 area by 17Z-19Z and the I-57
corridor by 21Z-23Z. This will be associated with MVFR cigs and
vsbys, especially westward toward I-55. Until then, only a few
light showers expected. Showers and thunderstorms will decrease
after 03-05Z, with lingering MVFR cigs. Winds SSW 10-15 kts
increasing to 14-18kts with gusts 22-25 kts by 18Z. Winds turning
W-NW and decreasing after 03-09Z.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through late tonight for ILZ027>031-036-037-
040-041-047>050.

&&

$$

SYNOPSIS...07
SHORT TERM...07
LONG TERM...07
AVIATION...37



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