Area Forecast Discussion
Issued by NWS Central Illinois

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246
FXUS63 KILX 251742
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1242 PM CDT SAT JUN 25 2016

.UPDATE...
Issued at 1015 AM CDT Sat Jun 25 2016

15z/10am surface analysis shows warm front extending from
Minnesota S/SE along the Mississippi River into southern Illinois.
A cluster of thunderstorms that had developed along the front
earlier this morning has all but completely dissipated over
northeast Missouri as it tracks further away from the weakening
nocturnal low-level jet. HRRR has not been doing a particularly
good job with this convection, consistently showing it spilling
into the SW KILX CWA between 15z/16z. Based on satellite/radar
trends, the Rapid Refresh seems to have a better handle on the
situation...showing the initial cluster dissipating then
additional scattered convection developing along the front between
18z and 21z. Have updated the forecast to better reflect PoP
trends for the remainder of the morning into the afternoon. Will
keep much of the area dry through midday, then will confine all
rain chances along/west of a Lacon...to Lincoln...to Shelbyville
line this afternoon. Will be a hot and humid day, with afternoon
highs reaching the lower to middle 90s and heat index values
approaching 100 degrees.

&&

.SHORT TERM...(Today)
ISSUED AT 248 AM CDT Sat Jun 25 2016

Surface high pressure will continue to move east today into New
England while Low pressure moves from the Dakotas into Manitoba
initiating a moist southerly flow into central IL. The stalled
frontal boundary from the Dakotas to southern IL will push into
western IL as a weak warm front bringing at least a slight chance
of showers and thunderstorms to areas west of a Bloomington to
Effingham line by afternoon. Despite mixed layer CAPE to around
2500 J/KG in this area, surface-6KM bulk shear around 15 kts or
less indicates little chance for severe storms. An increase in
temperatures and dewpoints can also be expected in this pattern with
temperatures rising to the low 90s and dewpoints in the low 70s to
make it somewhat hot and humid compared to yesterday. Heat index
expected to range from 95 to 100 by mid afternoon, compared with
yesterday`s upper 80s.

.LONG TERM...(Tonight through Friday)
ISSUED AT 248 AM CDT Sat Jun 25 2016

Upper low currently along the Montana/Alberta border will be
tracking east-northeast this weekend, dragging an associated cold
front across the Midwest later tonight through Sunday. A few stray
storms may linger in the evening from the diurnal development later
today, but main action should be as the front gets closer. While
mixed layer CAPE`s are progged to reach into the 1500-2000 J/kg
range Sunday afternoon, 0-6km shear is fairly meager and mainly
focused near the front. Some stronger storms may cause some brief
higher wind gusts, but widespread severe weather is not anticipated.
Temperatures most areas on Sunday will likely be closer to 90, with
lower 90s south of I-70, although any widespread cloudiness from the
storms may end up keeping temperatures a couple degrees lower.

A couple days of quiet weather are on tap Monday and Tuesday, as a
strengthening upper trough swings through the Great Lakes. This will
bring some cooler conditions for Tuesday through Wednesday, with
highs in the upper 70s to around 80 and quite low (for late June)
dew points of 50-55.

Latest models continue to shift any potential MCS tracks more to the
southwest of us during the latter part of the week. Have trended any
mentionable PoP`s Wednesday night and Thursday to mainly the
southwest corner of the CWA, but elsewhere, am reluctant to remove
them completely with the upper trough swinging through.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1242 PM CDT Sat Jun 25 2016

Despite approaching warm front, 1725z visible satellite imagery is
showing very little Cu development. High-res models have
generally been too aggressive with scattered convection late this
morning, so have opted to remove VCTS at the western terminals
this afternoon. Cold front currently over the eastern Dakotas into
the Plains will approach from the northwest tonight and arrive in
central Illinois on Sunday. Some models are suggesting widely
scattered convection well ahead of the boundary tonight, but think
this is probably overdone. As a result, have gone with a dry
forecast overnight, then introduced VCTS at the TAF sites between
13z and 16z as better forcing associated with the front arrives.
Winds will be light and southerly this afternoon and tonight, then
will veer to the southwest by Sunday morning.

&&

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

$$

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



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