Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 162032
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
332 PM CDT Wed Aug 16 2017

.SHORT TERM...  (Through Late Thursday Afternoon)
Issued at 332 PM CDT Wed Aug 16 2017

A line of showers and isolated severe thunderstorms  currently in
central Missouri will rapidly move east through the region. This
first line of showers and thunderstorms will bring uncertainty to
the second line which will be highly dependent on if the atmosphere
has time to recover before the second line forms ahead of the cold
front.  The cold front is currently in northwest Missouri will move
into central Missouri late this afternoon, then through the rest of
the area this evening. An additional line of showers and
thunderstorms is expected and reflected through several HRRR/CAMS
runs. The CAMS runs have been inconsistent in evolution of storms.
If the atmosphere can recover. the primary threats will be damaging
winds and large hail. An isolated tornado is also possible late this
afternoon and evening particularly with the line of thunderstorms
just ahead of the cold front with sufficient bulk shear of 45 to 50
knots along with surface CAPE values in excess of 3500J/kg.


High pressure will move into the area with partly cloudy skies on
Thursday with seasonal temperatures expected and this is reflected
in forecast temperatures.



Kelly


.LONG TERM...  (Thursday Night through Next Wednesday)
Issued at 332 PM CDT Wed Aug 16 2017

Thursday night through next Wednesday

A couple of strong systems will affect the area over the long term
however it looks like there will be just enough of a break in
btweeen to get the eclipse in.

The first system moves through by Thursday evening with a clearing
sky and drier air moving in for Friday. However another short wave
moves in on the northwest flow Friday night into Saturday bringing
anorther chance of showers and storms. The surface front should be
clear of the area by midday Saturday. The models are now tending to
produce some ridging across the area Saturday into Monday. This was
best seen while looking at the ensembles of the GFS. The ECMWF is
also trending this way as it has now moved any precipitation for
Sunday night into Monday morning well to the north. So conditions
are looking pretty good for the eclipse in the LSX CWA. Can`t rule
out an isolated shower or thunderstorm Monday, but it should hold
off until later in the afternoon.

The next short wave and associated front moves in Tuesday afternoon
into Wednesday morning with chances for showers and thunderstorms.
Temperatures are pretty seasonable with the warmest day looking to
be Monday.

JPK

&&

.AVIATION...  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1249 PM CDT Wed Aug 16 2017

A line of showers and thunderstorms with brief gusty winds is now
approaching central Missouri. A brief period of MVFR/IFR ceilings
and conditions possible in areas of showers and thunderstorms
with brief gusty winds through late tonight. Otherwise, VFR
ceilings and conditions are expected through Thursday afternoon.



SPECIFICS FOR KSTL:
Scattered showers and thunderstorm with brief gusty winds possible
through late afternoon will lead to brief periods of MVFR
conditions. A brief period of MVFR/IFR ceilings and conditions
possible in areas of showers and thunderstormswith brief gusty
winds through late tonight. Otherwise, VFR ceilings and
conditions are expected through Thursday afternoon.

Kelly

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX


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