Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 251947

Area Forecast Discussion
National Weather Service Saint Louis MO
247 PM CDT Tue Jun 25 2019

.SHORT TERM...  (Through Late Wednesday Night)
Issued at 245 PM CDT Tue Jun 25 2019

The threat of thunderstorms this evening continues to decrease as
the focus for development has shifted north into southern Iowa
where the cold front resides this afternoon. Majority of the short
term convective allowing models keep the CWA dry now, so have
decreased PoPs to chance and limited them to the northern tier of
counties in MO and IL. The guidance also shows a rapid decrease in
intensity after sunset and therefore the threat of severe weather
remains conditional and quite honestly, low for our northern CWA
this evening.

The upper level ridge begins to build north into the central
Plains on Wednesday but our CWA remains on the eastern periphery
and any MCV, or weak upper level disturbance floating across the
area during the afternoon could lead to a diurnal surge of
thunderstorm activity. About half of the guidance shows this
scenario with thunderstorms initiating during the afternoon across
the southeastern half of the CWA. Have maintained slight
chance/chance PoPs for this reason and expect later shifts to
refine based on upstream observations tonight.


.LONG TERM...  (Thursday through Next Tuesday)
Issued at 245 PM CDT Tue Jun 25 2019

The ridge will continue to build across the Plains and into the
upper Midwest through the weekend. Temperatures will slowly warm
into the 90s for afternoon highs. Have maintained a largely dry
forecast for the end of the week and weekend, but the orientation
of the ridge from roughly New Mexico to Minnesota does give me
some pause. The classic "ring of fire" would suggest that at least
our eastern CWA could be under the gun for any MCS or outflow that
drops south from northern Illinois this weekend.



.AVIATION...  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1203 PM CDT Tue Jun 25 2019

VFR conditions expected with convection staying limited to
extreme northern MO this evening. Wind to remain out of the
south-southwest. Some of the model guidance is hinting at
convection developing across the area tomorrow afternoon, but that
is based on a left over circulation from this evenings convection.
Therefore confidence remains fairly low at this time for
thunderstorm development tomorrow afternoon and is not included in
the TAF for KSTL.





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