Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 200415

Area Forecast Discussion
National Weather Service Lincoln IL
1115 PM CDT SUN JUN 19 2016

Issued at 855 PM CDT Sun Jun 19 2016

Surface dew points have risen quite a bit over the past 24 hours
with most of our area now in the upper 60s to lower 70s. The
better moisture transport this afternoon and early this evening
was over parts of southeast through east central Illinois where
several showers have tracked northeast from the upper Ohio Valley
into our region. Those are expected to dissipate over the next
hour or so with the loss of daytime heating. Meanwhile, further
northwest, a cold front was across western Minnesota southwest
through central Nebraska with the better coverage of storms
over central Minnesota. This front the and the threat for
scattered thunderstorms will shift east and southeast overnight
and move into our area Monday afternoon and evening. This will
bring us one more hot day with afternoon temperatures soaring
into the lower 90s, which should fuel the afternoon and evening
thunderstorms over parts of central Illinois. The current forecast
has a good handle on the evening and overnight trends, as a result,
no ZFP update will be needed this evening.


.SHORT TERM...(Tonight)
ISSUED AT 254 PM CDT Sun Jun 19 2016

Isolated convective cells were along and just south of I-70 at mid
afternoon and drifting northeast. LAPS at 19Z/2 pm shows CAPES of 1-
2K J/KG south of I-72 and supporting this isolated convection.
Scattered to broken cumulus cloud field with bases of 5-8k ft
extended as far north as a Quincy to Lincoln to Hoopeston where
moist dewpoints were in the upper 60s to around 70F. Just few
cumulus clouds along and north of a Rushville to Bloomington line
where drier dewpoints in the upper 50s and lower 60s. 1028 mb
surface high pressure over the mid Atlantic states was still ridging
westward into IL and the mid MS river valley. Southwest winds 5-15
mph with few gusts around 20 mph over sunnier areas of northern CWA,
was giving very warm temperatures in the upper 80s to around 90F
(except mid 80s at Danville). Aloft a strong 600 dm 500 mb high was
near the AZ/NM border and ridging northeast across IL where 500 mb
heights were above 594 dm. Isolated convection will dissipate over
southeast IL around 00z/7 pm as cumulus clouds dissipate as well
along and south of I-70 after sunset. So fair skies expected much of
tonight with SSW winds 5-10 mph after sunset. Mild lows in the lower
70s overnight which similar MET/MAV reflect.

.LONG TERM...(Monday through Sunday)
ISSUED AT 254 PM CDT Sun Jun 19 2016

Cold frontal boundary currently from NW NE to NW MN will push
southeastward into central IL Monday afternoon reaching roughly
Galesburg-Bloomington mid afternoon and settling slowly southward to
Flora-Lawrenceville by Tuesday morning. Convergence along the front
should promote scattered thunderstorms along the front. With warm
and humid conditions preceding the front...should have 1500-2500
J/KG CAPE with sfc-6 km bulk shear values around 30 kts for the
afternoon-evening. The associated shortwave and upper level jet
remain to the north, however, so lift will be relatively weak. As a
result...SPC has a marginal risk for severe thunderstorms from
roughly Springfield to Bloomington southward. Warm temperatures in
the lower 90s with heat indices in the upper 90s to near 100 degrees
will precede the front.

The front will stall out just south of the central/SE IL forecast
area early Tuesday and begin to lift northward later Tuesday as a
warm front. By Tuesday evening...this should result in another
chance for thunderstorms across central IL...and SPC has put out a
slight risk from roughly Springfield and Peoria westward Tuesday to
cover the potential of this feature.

The pattern becomes supportive of potential MCS features passing
through the state from Tuesday night through Wednesday
night...although uncertainty remains high at this time with regard
to these features.  Essentially chance PoPs remain in the forecast
through Thursday to account for this.

Temperatures Tuesday cool to the low to mid 80s following the cold
front...then warm right back into mainly the upper 80s for the
remainder of the week and weekend.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1110 PM CDT Sun Jun 19 2016

VFR conditions are expected through this forecast period. Main
concern will be the threat for widely scattered TSRA along a
southward moving cold front in the 20z-00z time frame, starting
in PIA and BMI with SPI, DEC and CMI seeing the chance closer to
00z. Forecast soundings indicating sct-bkn cumulus to develop by
early afternoon with bases in the 4500 to 6000 foot range. If a
TAF site does experience a TSRA, bring MVFR cigs/vsbys will be
possible, but based on the latest data, coverage still appears
to limited to include much more than VCTS at this time. The TSRA
threat and cool front will shift south of the TAF sites in the
00z-03z time frame with surface winds ahead of the front from the
southwest to west at 10 to 15 kts with a few gusts up to 20 kts at
times, with a northwest winds of 8 to 14 kts behind the front late
tomorrow afternoon into tomorrow night.


.ILX Watches/Warnings/Advisories...


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