Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 280447

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1147 PM CDT Sat May 27 2017

.SHORT TERM...  (Through Late Sunday Afternoon)
Issued at 313 PM CDT Sat May 27 2017

Severe weather watches will continue across central and southeast
MO and southwest IL into the evening hours. Supercells were
occuring across parts of southeast MO with bow echoes in central
and southwest MO. These bow echoes may consolidate into a larger
squall line late this afternoon. Once this squall line clears our
forecast area by late evening we should just have some lingering
showers and a few storms. Most of the convection should shift
south of our forecast area by midnight. Will still have a chance
of showers and storms on Sunday until an upper level trough
centered over the northern Plains and a cold front shift east-
southeast of our forecast area. Any severe weather threat should
be southeast of the forecast area on Sunday.


.LONG TERM...  (Sunday Night through Next Saturday)
Issued at 313 PM CDT Sat May 27 2017

Cooler conditions can be expected Sunday night due to a clear sky
and lower surface dew points. Another cold front will drop
southeastward through our area Monday afternoon and evening, but
little if any precipitation is expected with this front. A better
chance of showers may occur on Tuesday as a northwest flow
shortwave moves through our area. A surface ridge will build into
the region from the northern Plains on Wednesday shunting better
moisture and any precipitation threat south of our forecast area.
As this surface ridge shifts east of the region Thursday return
southerly flow on the backside of the ridge should lead to
increasing moisture and the potential for convection Thursday
night and Friday.



.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1142 PM CDT Sat May 27 2017

Threat of thunderstorms overnight have pushed well off to the
south of the terminals. Will have to watch for fog potential
overnight but thinking thick mid/upper level cloud cover will help
prevent fog formation, though cannot rule out some MVFR
visibilities were it to occur. Cold front should move through from
west to east late Sunday morning through early afternoon. Will be
isolated thunderstorms possible along/ahead of front though
probability too low to mention in TAF. Winds behind the front will
become predominantly northwesterly.


VFR conditions likely overnight. Slight chance at some MVFR visbys
in fog but probability too low. Isolated showers/storms possible
along cold front late Sunday morning through early afternoon.
Winds become northwesterly behind the front.





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