Area Forecast Discussion
Issued by NWS Central Illinois

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KILX 251521
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1021 AM CDT THU AUG 25 2016

.UPDATE...
Issued at 1021 AM CDT Thu Aug 25 2016

15z/10am regional satellite/radar imagery shows a Mesoscale
Convective Vortex(MCV) over northeast Kansas. This feature is
tracking northeastward and will likely impact the weather across
central Illinois this afternoon. While some models such as the 12z
NAM fail to pick up on this system at all, others like the HRRR
suggest scattered convection will develop along its eastern and
southern flank during peak heating. Following the latter solution,
have opted to go with a dry forecast across the board this
morning, followed by high chance PoPs over the northern half of
the CWA this afternoon into the early evening. Areas along/south
of I-70 will likely remain dry through the entire day. Due to
persistent cloud cover and scattered showers/storms arriving this
afternoon, have lowered high temperatures into the upper 70s from
the Peoria area northward. Further south, highs will mainly be in
the lower to middle 80s, but will reach the upper 80s to around 90
south of I-70 where sunshine will be prevalent throughout the
day.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 318 AM CDT Thu Aug 25 2016

Showers and isolated storms will be ongoing this morning, mainly
north of I-72. However, this precip will begin diminishing through
the morning hours. With boundary still sitting in the area, will
have to keep some form of pops in the forecast for rest of the
morning and through the afternoon. So, will have likely pops early
int the northeast and then chance elsewhere. However, with precip
decreasing, pops will be more slight chance, or isolated, into the
afternoon. Given the diminishing precip, the flash flood watch
has been cancelled early. Temps should be around normal north of the
sfc boundary, but above normal for areas south of the boundary,
which would be most of central and southeast IL...along and south of
I-72.

.LONG TERM...(Friday through Wednesday)
ISSUED AT 318 AM CDT Thu Aug 25 2016

Latest model guidance does not push the cold front as far south as
previous runs, and already begins to lift it back north as a warm
front on Friday. Consequently, added some 20-30% PoP`s to the
southwest parts of the CWA during the day. Most of the models focus
on some sort of MCS development across Iowa/Missouri Friday night
and track it northeast, with the ECMWF most bullish with a more
eastward track into Illinois by morning. Have not gone that extreme
yet, but have bumped up PoP`s from the earlier forecasts and
included a period of 60% PoP`s northwest of the Illinois River by
Saturday morning.

Late weekend and early next week remains a bit challenging, with the
potential breakdown of the southeast U.S. upper high. GFS and ECMWF
have wildly different solutions with tropical weather potential and
how it would break down the ridge. The GFS is in the much weaker
camp for the tropical system and thus keeps quite a bit of
convection going north of the ridge, while the ECMWF solution is
more of a diurnal nature for our area. Will largely only carry
slight chances of rain/storms in the extended periods, with some
30`s here and there, mainly in the southern CWA.

No real significant push of cool air expected behind the current
system, so most of the CWA should still see highs in the mid-upper
80s on Friday. Good portion of the forecast range beyond that will
remain muggy, with highs in the mid 80s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 645 AM CDT Thu Aug 25 2016

Lower clouds and vis is only at PIA which is very close to the
frontal boundary. These conditions at PIA will quickly improve
this morning, by around 14z. All other TAF sites just have
scattered AC. Thinking is that clouds will remain scattered with
some CU developing at all sites later this morning and continuing
this afternoon. At all sites, will also have a TEMPO groups for
broken CU given the rain that occurred last night and that the
frontal boundary is supposed to drop into the area this afternoon,
which should also cause broken clouds. Once the front drops south
of TAF sites, clouds will scatter again in the evening with some
high cirrus. Winds will be southwesterly ahead of the front and
then become west this morning and afternoon, then northwest once
the front moves through.


&&

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

$$

UPDATE...Barnes
SHORT TERM...Auten
LONG TERM...Geelhart
AVIATION...Auten



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.