Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 200809

Area Forecast Discussion
National Weather Service Lincoln IL
309 AM CDT WED JUL 20 2016

.SHORT TERM...(Today and tonight)
ISSUED AT 306 AM CDT Wed Jul 20 2016

Remnants of early MCS is finally moving off to the east of the area
but cloud cover remains over the area early this morning. This cloud
cover has hampered fog development, even with the light winds. So
will not have any fog mentioned in the forecast for early this

Short-term/HiRes models continue to show development of showers and
thunderstorms this morning along a warm frontal-type zone, but
mainly in the west and central parts of the cwa, and specifically in
the morning through early afternoon. Based on the models, this pcpn
dissipates during the afternoon hours and doesn`t reach the eastern
parts of the CWA. So, will have a chance pops for this morning in
the west and central and continue it into the afternoon hours, but
decrease it into the slight chance category for the afternoon and
into the evening. Will keep a slight chance in the far east for the
overnight hours, while the remainder of the CWA should be dry

Temps will be quite warm again today, reaching into the lower 90s in
the west, while still remaining in the mid to upper 80s in the east
and northeast. Dewpoints should push back into the mid 70s by this
afternoon, resulting in HI over 100 over most of the area. Western
areas of the CWA could see advisory criteria being reached, 105, but
only for an hour or two. Therefore will not be making any changes to
current headlines.


.LONG TERM...(Thursday through Tuesday)
ISSUED AT 306 AM CDT Wed Jul 20 2016

Primary focus remains with the heat into the weekend, as massive 598
dm upper high switches to more of a west-east configuration this
weekend. Associated cold front which will bring some relief is not
expected to reach the area until Sunday, as the upper low currently
off the Washington coast opens up and tracks along the Canadian
border this weekend.

No changes being planned for the Excessive Heat Watch yet, but an
upgrade to a warning or advisory will soon be needed. Main concern
is the duration of the peak heat indices. Local warning criteria
calls for 110+ peak heat index for 2 days with nighttime heat index
at least 75F. Friday still is fairly solid in that potential, but
Thursday and Saturday are a bit more iffy and dependent on any
convective cloud debris to our north. Latest guidance suggests areas
east of I-55 may still have 105+ heat index as late as Sunday, which
would satisfy the alternate criteria of 105+ heat index for at least
4 days, but scattered storms are more of a potential with the front
and so this level of heat is more uncertain.

In terms of the actual temperatures, went a bit above MOS guidance
for Thursday as forecast soundings indicate high temperatures in the
mid 90s as far north as Peoria, and went closer to a NAM/GFS MOS
blend for Friday. Temperatures at least in the lower 90s are still
likely into the weekend, before the front passes and more tolerable
mid-80s highs returns early next week.

Main time frame for any showers/storms is mainly this weekend,
especially Sunday as the front arrives. Mid-level capping may break
enough on Saturday for a few storms to form, but main focus will be
on Sunday.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1100 PM CDT Tue Jul 19 2016

Convection continues to slowly shift south and east with CMI
possibly seeing a round or two of TSRA over the next few hours.
Otherwise, additional showers and scattered storms will be
possible towards dawn along a northward moving warm front that
was temporarily pushes south of our area earlier this evening
by all the convection that occurred over the western half of
the forecast area. The aforementioned frontal boundary may take
until later tomorrow night to clear our forecast area, as a
result, at least a chance for scattered TSRA will be with us into
late Wednesday/Wed evening. Just where the storms will reignite
and the coverage area is still quite uncertain at this time into
the daylight hours of Wednesday.

Some patchy MVFR fog will develop with all the low level moisture
in place from the rainfall and a very light wind regime forecast
to hold thru Wednesday. We should see surface winds tend to become
more southeast to south during the day on Wednesday with speeds of
10 kts or less. Any TAF location that does see thunderstorm move
across the area, will see a tempo lowering to MVFR or even IFR for
a brief time before returning to VFR.


.ILX Watches/Warnings/Advisories...
Excessive Heat Watch from Thursday afternoon through Saturday
evening for ILZ027>031-036>038-040>057-061>063-066>068-071>073.



LONG TERM...Geelhart
AVIATION...Smith is the U.S. government's official web portal to all federal, state and local government web resources and services.