Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 191203

703 AM CDT Sun Apr 19 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 405 AM CDT Sun Apr 19 2015

An area of showers and storms across southeast MO and southern IL
associated with a surface low near the MO bootheel will shift
northward through much of the forecast area this morning,
particularly the eastern half as the surface low moves northeastward
into southern IL by 18Z Sunday.  More scattered activity is expected
this afternoon as the upper level low over western KS opens up and
shifts eastward to near the KS MO border by 00Z Monday.  The models
depict upper level divergence over our forecast area ahead of the
upper level trough.  Some of the high resolution explicit models
depict a narrow line of convection shifting eastward through our
forecast area this afternoon.  With more cloud cover and
precipitation today the highs will not be quite as warm as
yesterday, but will still be slightly above normal.


.LONG TERM:  (Tonight through Saturday)
Issued at 443 AM CDT Sun Apr 19 2015

Showers and thunderstorms will continue tonight as the upper level
trough and associated cold front move eastward through our area.
The GFS model has a little higher pops and QPF over a portion of our
area tonight as it develops a surface low on the front which moves
northeastward through southeast MO and southern IL.  The other
models do not develop this surface low so am not real confident of
the GFS forecast solution and its higher pops and QPF.  Showers may
linger across IL Monday morning as more shortwaves move through the
area south of a northern Plains upper level trough.  Colder
temperatures can be expected tonight and Monday due to low level
cold air advection after the passage of the 850 mb trough and
surface cold front.  A persistent period of below normal
temperatures is expected for the upcoming work week due to the upper
level trough over the Great Lakes region and northwest flow over our
area.  More showers are expected Tuesday afternoon, mainly across
the southern half of our forecast area due to low-mid level warm air
advection ahead of a fast moving shortwave.  The chance of rain will
continue Tuesday night and Wednesday as a cold front drops southward
through our area.  This will bring a reinforcing shot of colder air
to the region Wednesday and Wednesday night with the models dropping
the zero degree C 850 mb isotherm southward to around STL.  Another
chance of rain is expected for Friday night and Saturday as an upper
level trough/low and associated surface low move eastward through
the region.



.AVIATION:  (For the 12z TAFs through 12z Monday Morning)
Issued at 636 AM CDT Sun Apr 19 2015

An area of rain across SE MO and sthrn IL will continue to spread
north thru the mrng as the responsible sfc low moves from the MO
bootheel to W cntrl IN today. There could be some embedded
thunder in this batch of precip but think most of it will be VFR
occnlly MVFR with any heavier precip. Having said that KUUV has
an 800 ft CIG...but appears to be isld. Precip should lift north
of the area by aftn but addtnl scttrd convection is expected to
dvlp later this aftn into the evng. Attempted to cover this threat
with VCTS for now with future updates likely once storms start to
initiate. There appears to be a lull from late this evng thru
midnight before another area of precip assoc with an upper lvl
disturbance and a cold front moves into the region. Best chances
for precip with this batch appears to be along and south of I70.
FROPA should be between 6-12Z with models indicating a band of
MVFR CIGS...if not lower...behind the bndry. A gusty W/NW breeze
is fcst to dvlp by 12Z as a sfc ridge builds in from the plains.

Specifics for KSTL:

MVFR conditions and SHRAs will be the rule thru midday with addtnl
convection possible for the aftn/evng. Should be somewhat of a
break in the precip potential from late this evng thru midnight
before another batch of rain approaches the terminal after 6Z.
Cold frontal passage is expected late tonight with should create a
gusty W/NW breeze. A band of MVFR CIGs...possibly
expected to accompany the front.





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