Area Forecast Discussion
Issued by NWS Central Illinois

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934
FXUS63 KILX 241756
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1256 PM CDT Sat Jun 24 2017

.UPDATE...
Issued at 1045 AM CDT Sat Jun 24 2017

Updated the forecast to increase cloud cover with a bit more
cumulus clouds developing along with a bit strong WNW winds.
Partly to mostly sunny skies the rest of today with the scattered
cumulus clouds dissipating toward sunset this evening. Highs in
the mid to upper 70s, with breezy WNW winds of 10-15 mph and gusts
to around 25 mph.

Late morning surface map shows 1029 mb Canadian high pressure
along the British Columbia and Alberta province line and ridging
se into KS. A chunk of this high pressure (1021 mb) will drift
across KS and into MO by sunset and ridge into central IL
providing fair and dry weather today. A 554 dm 500 mb low over
central MN will weaken to 557 dm as it tracks into NW/west central
WI by sunset and into central Lake MI early overnight. A deepening
upper level trof into the Midwest including central IL is helping
to develop the scattered cumulus clouds with bases of 3-5k ft with
a few broken ceilings possible especially ne of I-74. Temps
currently in the upper 60s and lower 70s should climb into the mid
to upper 70s by mid/late afternoon. Dewpoints in the upper 40s and
lower 50s over IL river valley and upper 50s and lower 60s in
southeast IL will mix out and slip a few more degrees during the
afternoon.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 321 AM CDT Sat Jun 24 2017
The forecast is pretty quiet for this round. Mild through the
weekend, and precip chances holding off for Central Illinois until
later in the week.

The cold front that has left far milder air behind here in the
Midwest has progressed to roughly the Appalachians this morning.
High pressure is trying to build into the region...with the ridge
oriented more NW/SE over the Plains. As a result...winds on this
side of the developing ridge are more northwesterly and will
continue that way through today...becoming more westerly later
tonight as the winds decouple. Not too far off the sfc, the winds
pick up a few knots...so including gusts near 20 kts for this
afternoon.

.LONG TERM...(Sunday through Friday)
ISSUED AT 321 AM CDT Sat Jun 24 2017
Cooler through the rest of the weekend...and dry. A quick wave
rippling into the region later on Monday. Previous runs and to an
extent the most recent ECMWF keeping precip to the north...but
the GFS has come in a little more aggressive and widespread with
slight chances in the forecast for Monday afternoon/night.
Forecast slowly warms a couple degrees each day, however, late
Tuesday, as the wave aloft passes through the Great Lakes, the
northwesterly flow aloft breaks down as the 850mb thermal ridge
shifts to the east...opening up the region to the deep warm air
over the desert SW. 850 mb temps warm from 8-10C on Tuesday
night...to 17-18C by Wednesday evening. Temperatures at the
surface climb a good 7 to 9F on Wednesday and stay warm through
the end of the week. Flow aloft starts to look more zonal again,
and temps and RH continue to increase through the end of the week
in a more southerly flow regime. Timing and depth of wave that
brings pops back into the forecast for the end of the week and
into next weekend is very low confidence at this point and the
forecast is dominated by rain.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1255 PM CDT Sat Jun 24 2017

VFR conditions are forecast to continue across the central IL
airports through 18Z/1 pm Sunday as today`s weather will be
repeated tomorrow. 1028 mb Canadian high pressure along the
British Columbia and Alberta province line and ridging se into KS
will have a chunk of high pressure break off and move from KS
into MO by Sunday evening. Meanwhile a 554 dm 500 mb low over
central MN will weaken to 558 dm as it tracks eastward to the
east side of Georgian Bay by 18Z/1 pm Sunday. Its isolated/scattered
convection should stay north of central IL next 24 hours. Few to
scattered cumulus clouds with bases of 4-6k ft over central IL
this afternoon and possible brief broken ceilings at CMI into mid
afternoon, will dissipate at sunset. Expect few-sct cumulus clouds
to appear again between 14-15Z/9-10 am Sunday. Breeze WNW winds
of 10-15 kts and gusts 17-24 kts will diminish to 4-8 kts after
sunset and veer WSW. Expect breezy WNW winds 10-15 kts and gusts
near 20 kts again after 14Z/9 am Sunday.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

UPDATE...07
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...07



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