Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 020448

1148 PM CDT Fri Aug 1 2014

Issued at 832 PM CDT Fri Aug 1 2014

Updated grids and zones as showers and a few thunderstorms
continue to diminish early this evening. Otherwise, could see fog
develop especially in areas that saw some rain today.



.SHORT TERM:  (Through Late Tonight)
Issued at 330 PM CDT Fri Aug 1 2014

Water vapor imagery depicts a shortwave trough currently along the
Missouri River SE of KOAX heading southeast and will be the main
feature of interest tonight. Scattered showers and thunderstorms
have persisted through early this afternoon and believe they will continue
to survive into the evening hours. However...with loss of
instability...precipitation should become more showery and devoid
of thunder similar to what happened last night across northwest

Drier weather with decreasing cloudiness is expected behind this feature
setting the stage for another cool summer night. Other concern then turns
to fog as winds remain light/variable or calm. Combine that with fairly
clear skies expected late tonight and higher dewpoints compared to a
of days ago...did add mention of patchy fog for the entire CWA as
forecast minimums in most of these locales are several degrees
below crossover temperatures. Dense fog will be more likely in
areas which receive higher rainfall totals through this evening.


.LONG TERM:  (Saturday through Next Friday)
Issued at 330 PM CDT Fri Aug 1 2014

(Saturday - Friday)

Secondary shortwave trough looks to be a bit further to the east tomorrow
than it was modeled 24 hours ago. Consequently...did drop the sch PoPs
along and east of the Mississippi River. Also yielded toward the warmer
guidance with respect to highs tomorrow due to less expected diurnal cu
as well as a slight warming in 850-hPa temperatures.

Sunday and Monday also look dry with high temperatures back to near normal
for early August.

A more active pattern still could be in the offing for the middle to late
next week as bi-state area will lie beneath quasi-zonal/WNW flow
aloft. At least a few shortwave troughs will come across during
this time frame and should interact with a tightening low-level
baroclinic zone. Only have chance PoPs Wednesday - Friday for now
due to uncertainty/timing issues...but does appear that we will be
heading into a much wetter pattern than the past couple of weeks.
As for temperatures...lows will likely remain near or even
slightly above normal but highs are forecast to return to slightly
below normal due to expected clouds/rain chances.



.AVIATION:  (For the 06z TAFs through 06z Saturday Night)
Issued at 1147 PM CDT Fri Aug 1 2014

Areas of fog are continuing to develop late this evening with KSUS
just falling below 2SM. Now expect all of the TAF sites to have
fog tonight, with the lowest visibilities most likely at KSUS and
KCPS. Visibilities may vary though...going from MVFR to LIFR
depending on the airport with the lowest visibilities being
between 10-12Z. Fog should lift by 13Z as it has the past several
mornings with scattered clouds developing between 16-18Z. Expect
dry conditions with light winds through the period.

Specifics for KSTL: Still expect some MVFR fog to develop at the
terminal between 10-13Z because of the higher moisture in the
atmosphere tonight. Otherwise expect a dry conditions with light
winds the next 30 hours.





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