Area Forecast Discussion
Issued by NWS St. Louis, MO

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034
FXUS63 KLSX 300828
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
328 AM CDT FRI SEP 30 2016

.SHORT TERM... (Through Sunday Night)
Issued at 254 AM CDT Fri Sep 30 2016

A closed and nearly stacked low pressure system was centered over
TN/KY early this morning. This feature will slowly meander
northward over the next few days, eventually reaching the IN/MI
border by 00z Sun and then quickly moving towards the
northeastern CONUS. As long as the low pressure system remains
nearby, sfc winds will retain a northerly component and
substantial cloud cover will be present, particularly over the
eastern part of the CWA which will be closer to the low pressure
system. Light rain is also expected at times over the eastern CWA
today/tonight.

The combination of northerly winds and substantial cloud cover
will keep daytime high temperatures in the mid 60s to near 70
degrees for today and tomorrow. A slight warm-up is then
anticipated on Sunday due to the decreased influence of the
departing low pressure system.

Kanofsky

.LONG TERM... (Monday through Thursday)
Issued at 254 AM CDT Fri Sep 30 2016

Models depict a brief pd of upper ridging over MO/IL early next
week before a large low pressure system approaches from the west.
Although there is general agreement that this feature will bring
unsettled wx to our area during the middle of the week (roughly
Tue night through Thu night), there remains some model
disagreement over the location of this feature and its evolution.
The 00z ECMWF was farther north and depicted more of an open wave
while the 00z GFS solution had an initial track which was much
farther south but eventually developed into a closed low over the
Dakotas. A general fcst of SChc-Chc PoPs during the middle of the
week looks reasonable attm given the model disagreement.

Kanofsky

&&

.AVIATION...  (For the 06z TAFs through 06z Friday Night)
Issued at 1124 PM CDT Thu Sep 29 2016

Nearly stationary upper level low and surface troughing was over
KY with an upper level ridge and surface ridging over the Plains.
Low level clouds along with a few light showers continue to rotate
through eastern MO and IL on the backside of the low. The MOS
guidance was consistent in lowering the cloud ceiling down to
around 1000 feet late tonight. The cloud ceiling should gradually
rise late Friday morning and afternoon, but not likely above MVFR.
More significant showers should remain east of the taf sites
late tonight, with scattered showers for UIN and the St Louis
metro area Friday afternoon. N-nwly surface winds will continue
through the period.

SPECIFICS FOR KSTL: Nearly stationary upper level low and surface
troughing was over KY with an upper level ridge and surface
ridging over the Plains. Low level clouds along with a few light
showers continue to rotate through eastern MO and IL on the
backside of the low. The MOS guidance was consistent in lowering
the cloud ceiling down to around 1000 feet late tonight. The cloud
ceiling should gradually rise late Friday morning and afternoon,
but not likely above MVFR. More significant showers should remain
east of STL late tonight, with scattered showers for STL area Friday
afternoon. N-nwly surface winds will continue through the period.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX



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