Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 150445

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1145 PM CDT Sat Sep 14 2019

.SHORT TERM...  (Through Late Sunday Night)
Issued at 313 PM CDT Sat Sep 14 2019

Temperatures have begun to warm back up in the wake of the surface
high that is currently centered over southern Indiana. This high
will continue to move east through the Ohio Valley this evening
keeping winds from the south-southwest. Thunderstorms currently
over central Iowa are expected to stay north of the area this
evening. However, both the RAP/NAM are showing some weak low
level moisture convergence moving into northeast Missouri and west
central Illinois late tonight that will coincide with some weak
lift from a shortwave trough. Given the weak forcing and some
capping seen on the forecast soundings, will go with only slight
chances late tonight into early Sunday over the far northern part
of the CWA. Both the GFS/NAM show the upper high over the southern
CONUS building north over the Midwest on Sunday with a ridge over
western Missouri by late afternoon. 850mb temperatures will climb
back into the upper teens Celsius which with southwest winds
supports highs in the upper 80s and lower 90s on Sunday.


.LONG TERM...  (Monday through Next Saturday)
Issued at 313 PM CDT Sat Sep 14 2019

There is good agreement between the GFS/ECMWF/Canadian as well as
the GEFS mean that the upper ridge will remain over the Midwest
from Monday into early Wednesday before breaking down with the
approach of a upper trough. This supports dry weather over
Missouri and Illinois with continued above normal temperatures.
GEFS mean temperatures supports highs that are 10-15 degrees above
normal Monday into Wednesday. These combined with the forecast
dewpoints will produce heat indices in the 90s. The aforementioned
upper trough will bring a front that will stall over the area
Thursday into Friday. This will bring a chance of showers and
thunderstorms and slightly cooler temperatures.


.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1142 PM CDT Sat Sep 14 2019

Dry and VFR flight conditions expected through the forecast
period with light south winds veering to the southwest during the
morning on Sunday and picking up a bit, especially at KUIN and
KCOU. Otherwise, weak upper level shortwave will continue to
slide eastward along the IA/MO border late tonight with increasing
clouds and a slight chance of showers/storms near KUIN through
mid morning on Sunday, but confidence remains low, so kept TAF dry
for now.


Dry and VFR flight conditions expected through the forecast
period with light south winds veering to the southwest by 15z



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