Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 160938

Area Forecast Discussion
National Weather Service Lincoln IL
338 AM CST Thu Feb 16 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 338 AM CST Thu Feb 16 2017

A warm front will lift northeast through the area today as mid level
ridging builds in the plains. This will bring the return of
southwest winds and much warmer temperatures. Skies are currently
mostly clear, but satellite loop and HiRes models indicate that a
large area of cirrus will be streaming over the top of the ridge and
will advect over the CWA during the day and into tonight. Temps will
decrease this evening, but the continued southwest winds will keep
warm air advection in place over the area. Expecting afternoon highs
to range from around 50 in northeast to the lower 60s in the
southwest. Tonights lows should range from the mid 30s in the north
to the low 40s in the southwest.


.LONG TERM...(Friday through Wednesday)
ISSUED AT 338 AM CST Thu Feb 16 2017

The Feb 16th 00Z forecast models and their ensembles are in good
agreement with the overall weather pattern through early next week.
A strong/large upper ridge will dominate IL`s weather with
unseasonably mild temperatures Friday through the middle of next
week, with near record highs possible Saturday and Monday. Record
highs for Friday through Monday (Feb 17-20th) are included in the
climate section of this discussion.

The strong 512 dm 500 mb low over New England will lift up into the
Canadian maritimes through Fri night while strong upper level ridge
over the Rockies shifts east into the MS river valley by midday
Friday. SW winds and ample sunshine Friday along with 850 mb temps
of 10-12C supports milder highs in the low to mid 60s, with upper
60s sw of Springfield, like around Jacksonville. Lows Friday night
in the low to mid 40s with mildest readings sw CWA.

A 566 dm 500 mb low over nw Mexico, east of Baja, will eject ne into
the Ozarks of nw AR by 12Z/6 am Sat and into western KY/TN by
sunset Sat, then into the mid Atlantic states by 12Z/6 am Sunday.
Models have trended a bit further northward with light qpf into
southeast IL Sat especially Sat afternoon and have 20-30% chance of
light rain showers from Charleston/Mattoon south on Sat afternoon.
Think NAM model is too far north with qpf to the IL river on Sat
afternoon. Southern CWA will also see more cloud cover and keep
temps down a few degrees. Highs Sat still quite mild in the low to
mid 60s with Jacksonville area again expected to be the mildest.

Upper level ridge builds back into IL Sunday and shifts east over
the Ohio river valley Monday. This will return more sunshine on
Sunday along with warmer highs in mid 60s to near 70F on Sunday and
upper 60s and lower 70s Monday despite increasing cloud cover by
Mon. Most models now keep CWA dry on Monday with strong nearby
upper level ridge in place.

Next chance of rain showers expected to be along and north of I-72
by overnight Monday night and across the CWA on Tue, though pops are
only in the 20-40% range. Forecast models show a weakening front
moving into IL Tue while stronger cutoff lows north by James Bay
Canada and just south of Texas. A bit cooler but still quite mild
Tue with highs in the low to mid 60s, and some upper 60s south of I-
70. Models generally keep a flattened upper level ridge in place
over area during middle of next week along with continued mild temps.
But differences with qpf fields though consensus is best chances of
showers east of IL river Tue night and Wed and east of I-57 Wed
night before dry conditions across area next Thu. Highs Wed and Thu
still in the upper 50s and lower 60s.

CPC`s 8-14 day outlook for Feb 23-Mar 1 is 60% chance of above
normal temperatures and 40% chance of above normal precipitation.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1113 PM CST Wed Feb 15 2017

High pressure centered over the region late this evening will
drift off to our southeast by Thursday morning which will
allow our current light and variable winds to become southerly
by morning and increase to 12 to 17 kts by early afternoon.
Forecast soundings suggest some gusts up to 20 kts will be
possible in the afternoon, especially across our western TAF sites
(KPIA and KSPI). We are still watching a band of mid (6000-9000
feet) and high (~20000 feet) tracking southeast out of Wisconsin
which will continue into Thursday morning with scattered to broken
cirrus expected for the remainder of the day. The southerly winds
will diminish to around 10 kts by 00z.




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