Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 270853

Area Forecast Discussion
National Weather Service Saint Louis MO
353 AM CDT WED JUL 27 2016

.SHORT TERM...  (Through Late This Afternoon)
Issued at 312 AM CDT Wed Jul 27 2016

Despite some mid-high level cloudiness, fog has developed
overnight across portions of southeast MO and southwest IL due to
high surface dewpoints and calm winds. The fog was especially
dense in the FAM area. Scattered showers and thunderstorms are
expected to develop again later this morning and this afternoon,
mainly across southeast MO and southwest IL with the St. Louis
metro area on the northern fringe of most of the convection. This
activity will be associated with an old, weak frontal boundary
that has become stationary. High temperatures today will be
similar to yesterdays highs, and close to seasonal normals.


.LONG TERM...  (Tonight through Tuesday)
Issued at 312 AM CDT Wed Jul 27 2016

Relatively active pattern will continue for late July as
shortwaves carve out an upper level trough over the central US and
another weak, subtle cold front drops slowly southeastward through
our area Thursday and Thursday night. Will include chance pops
across most of the forecast area through the remainder of the work
week. The NAM model has a strong shortwave and associated surface
low moving eastward through MO and IL on Friday and Friday night.
It appears a little too strong with these features and prefer the
weaker solutions and lower QPF of the other models. The cloud
cover and precipitation should keep high temperatures to values
just below normal for Friday and Saturday. The chance of
convection should finally lessen, while the temperatures rise by the
start of the next work week as both the GFS and ECMWF models
depict a 595 decameter 500 mb high building over MO by Monday
night, along with mainly southerly or southwesterly surface winds.



.AVIATION...  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1157 PM CDT Tue Jul 26 2016

Clouds will linger across much of the area thru much of the night,
raising questions about how much fog will develop. For those areas
that received rain this evening, believe fog is much more likely.
Still, if holes in clouds develop, believe fog will impact most
terminals late tonight into Wed morning. Have added mention of
VCTS at KSTL/KSUS/KCPS with TSRA expected to be further north
during the afternoon hours Wed.





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