Area Forecast Discussion
Issued by NWS Springfield, MO

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FXUS63 KSGF 181704

Area Forecast Discussion
National Weather Service Springfield MO
1104 AM CST Thu Jan 18 2018

...Update to Aviation...

.SHORT TERM...(Today and tonight)
Issued at 230 AM CST Thu Jan 18 2018

A sfc ridge extends from west TN to east TX with gusty sw winds
expected to develop today. Warmer temperatures and low dew
points/RH will help eat away at the snow and in many cases melt
it all where the depth is shallow. Temperatures will be a little
tricky where deeper snow exists, and used a consensus short term
blend of guidance which seems to try to capture the slightly lower
temperatures in deeper snow cover.

.LONG TERM...(Friday through Wednesday)
Issued at 245 AM CST Thu Jan 18 2018

The main concerns will be with a strong system moving through the
region Sunday/Sunday night.

Friday-Saturday: We will continue to see a warming trend with
above normal temperatures for this period with gusty south winds.
Some low clouds/drizzle will be possible Saturday into Sunday as
shallow moisture return occurs ahead of an approaching system.

Sunday: A shortwave now over the eastern Pacific is expected to
move into the central/southern CA coast late Fri and Fri night and
then the central/southern Rockies by 12z/6am Sunday. Guidance then
differs somewhat on the timing/speed/placement of deepening sfc
low pressure as it moves ene into the Midwest Sunday night as the
shortwave continues to eject east. Modified Gulf moisture will
move northward ahead of the system with low/mid 50s sfc dew
points into our area ahead of sfc front. The GFS shows a very narrow
corridor of weak instability (mlcapes and mucapes 200-300 j/kg
with peak late day diurnal heating) moving across the area late
Sunday/early Sunday evening ahead of a dryline. This coupled with
a favorable synoptic scale vertical shear setup may briefly allow
some stronger shallow organized storms to develop. Given the weak
instability and potential timing issues, will continue the very
general/low confidence risk messaging for this time frame. Some
much needed rain is expected over the eastern cwfa/south central

Monday-Wednesday: The upper low shifts northeast and slows as it
closes off, so some lingering low clouds will be possible into
Monday and this is not going to be captured too well in a medium
range blended guidance data set. Otherwise, the air mass behind
the front is more Pacific based with temperatures near or slightly
above normal for the time of year into the midweek period.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1103 AM CST Thu Jan 18 2018

VFR conditions will prevail at the TAF sites this afternoon
through Friday morning. Gusty south to southwest winds will
develop over much of the area this afternoon and again Friday
morning. Low level winds shear may also develop and be a concern
across the area this evening and tonight.




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