Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 202013

Area Forecast Discussion
National Weather Service Lincoln IL
313 PM CDT Fri Jul 20 2018

.SHORT TERM...(This evening through Saturday)
ISSUED AT 310 PM CDT Fri Jul 20 2018

Mid afternoon surface map shows 1002 mb low pressure over
southeast WI, ne of Madison with its cold front moving toward I-70
in southeast IL. Most of the convection has been east of IL in
more unstable air mass ahead of cold front. A few showers were
along and ne of I-74. The slight risk of severe storms in
southeast IL next 1-2 hours, but this chances appears to be
lessening per latest radar trends and CAM models as cold front to
move thru se IL late this afternoon. A 573 dm 500 mb low over
southeast WI was producing broken to overcast cumulus clouds field
as far south as a Springfield to Paris line and more scattered
cumulus clouds south of this area. Upper level low and surface low
to track se to sw lower MI by midday Sat and to near the MI/OH/IN
border by sunset Sat. This will keep a chance of showers and
isolated thunderstorms around into Saturday especially in central
and eastern CWA. Lows tonight in the mid to upper 60s with highs
Saturday in the upper 70s and lower 80s, coolest from I-74 ne.


.LONG TERM...(Saturday night through Friday)
ISSUED AT 310 PM CDT Fri Jul 20 2018

Not much changes to the forecast from Saturday night through next
work week. Upper level low to track from the southern Great Lakes
to near the OH/KY border by Sunday afternoon and into eastern TN
on Monday as it slowly weakens. This feature will continue
diurnally enhanced showers and isolated thunderstorms Sunday
especially Sunday afternoon along with more cumulus clouds. Highs
Sunday again in the upper 70s/lower 80s, coolest over east central
IL. Could be some isolated showers in far southeast IL Monday
afternoon while most of CWA should be dry. Temps start moderating
a few degrees with more sunshine possible early next work week.
Highs Monday in the low to mid 80s and mid to upper 80s Tue which
is close to normal for late July. Weak upper level low to be over
the northern gulf coast Tue/Wed while another cutoff upper level
low passes north of Lake Superior by Wed night. Best chances of
showers and a few thunderstorms to be se and north of CWA during
mid week with seasonable temperatures. Seasonable humidity levels
persist next several days with dewpoints generally in the 60s.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1259 PM CDT Fri Jul 20 2018

A 572 dm 500 mb low near Madison in southern WI and associated
1002 mb surface low just ne of Madison, WI will slowly drift
southeast into sw lower MI by 18Z/1 pm Saturday. Its cold front
has pushed se of central IL airports by midday and will continue
to push through southeast IL by late afternoon. Thunderstorms
should stay se of central IL rest of today along and ahead of cold
front, but isolated to scattered light rain showers possible
especially along and north of I-74. MVFR clouds along I-74 to lift
bases to VFR during mid/late afternoon. Models then bring MVFR
ceilings back south into central IL later tonight into Saturday
morning including SPI and DEC airports too. WSW winds 10-15 kts
and gusts of 20-25 kts this afternoon to veer WNW late today and
NW by Saturday morning. Winds become less gusty by sunset, but
gusts to near 20 kts return after 14Z/9 am Sat.





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