Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 240147
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
847 PM CDT Thu Mar 23 2017

.UPDATE...
Issued at 840 PM CDT Thu Mar 23 2017

An upper level ridge continues to build north across the Mid-
Mississippi Valley this evening shifting any rain chances well to
our north and east. A gusty southeasterly wind tonight will
gradually turn more into the south later tonight as a warm front
shifts to our north with temperatures slowly rising overnight.
Windy and warm weather slated for Friday as a storm system slowly
pulls out of the southern Plains and heads northeast towards our
area as it slowly weakens. The gusty southerly winds on Friday
will help to push afternoon temperatures into the mid 70s across
the west with a bit cooler readings east and south as some lower
clouds track north into the area by afternoon. It still appears
the better chances for showers and isolated thunderstorms across
our area will be tomorrow night and Saturday. Have adjusted the
early evening temperatures and bumped the winds up for the
remainder of the night. We should have the updated ZFP out by
900 pm.

&&

.SHORT TERM...(This evening through Friday)
ISSUED AT 306 PM CDT Thu Mar 23 2017

Showers continuing to push eastward across the forecast area this
afternoon, but have struggled to make much headway from about Peoria-
Paris where dew points remain largely in the mid-upper 20s. The
clouds and rain have been keeping temperatures down, and were still
only around 40 degrees from about Rushville to Taylorville. However,
the back edge of the cloud shield has entered far western Illinois,
and some late afternoon clearing across the western CWA should help
get temperatures to rise some before sunset.

Significant warm air advection to take place tonight as a strong low
level jet ramps up (southwest winds around 60 knots at 925 mb). Low
temperatures will be early in the evening and temps will slowly rise
through the night, with many areas in the mid 50s by sunrise. Still
looking like much of the area should reach the 70-75 degree range
Friday with the highest values along the Illinois River valley.
Precipitation-wise, high-resolution models are in good agreement
with a narrow line of showers and storms forming across eastern Iowa
into central Missouri early Friday afternoon, with the bulk of this
arriving in our area during the evening. Have slowed PoP`s a bit and
focused them along and west of the Illinois River late in the
afternoon.

.LONG TERM...(Friday night through Thursday)
ISSUED AT 306 PM CDT Thu Mar 23 2017

Major trough seen in the moisture channel satellite imagery in the
southern rockies with upper ridge building over MS valley region.
Warm frontal pcpn has been trend through day today, but dry air in
the low levels has limited the extend of pcpn amounts.

Operational models are pretty close in agreement on the slow
movement of the vertically stacked upper low through the central US
into the weekend. Showers to move into region ahead of the close
upper low on Fri night, with scattered thunder possible Fri night.
lakc of instability will keep potential for severe low ahead of the
track of the upper low, so CWA will be in mainly periods of showers
on Sat into early Sun, with scattered lightning and tstms possible.
Showers slowly move out Sun.

Second shortwave to come out of trough into midwest for Monday,
spreading showers with it, with tstms mainly over the southern half.

12z EUR and Can a little faster on the movement of the 3rd system,
bringing showers into area again on late Wed night and on Thu. Will
have to watch the timing on this, far out in the future system.
Still looks weak though at this time.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 605 PM CDT Thu Mar 23 2017

The main forecast concern, at least thru tonight, will be with
the non-convective LLWS threat across the entire area starting
around 03z. Forecast soundings and time height cross sections
suggest south to southwest winds of 45-55 kts at around 1800
feet AGL from about 03z through 13z Friday. Initially, the
winds at 1800 feet should start out southerly and then veer more
southwest towards morning. Once daytime heating commences on
Friday, we should start to mix down some of the stronger winds to
the surface with gusts up to 28 kts possible, especially in BMI
and CMI by late morning into the afternoon hours. VFR conditions
will prevail into the morning hours before low level moisture
increases from the south bringing MVFR cigs north into the TAF
sites between 15z and 18z Friday. At the surface, winds tonight
will be southeast to south at 12 to 17 kts with a few gusts around
22 kts at times later tonight, and then south winds are expected
on Friday at 12 to 17 kts with again gusts at or above 25 kts into
the afternoon hours.


&&

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

$$

UPDATE...Smith
SHORT TERM...Geelhart
LONG TERM...Goetsch
AVIATION...Smith



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