Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 282027
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
327 PM CDT Sun May 28 2017

.SHORT TERM...  (Through Late Monday Afternoon)
Issued at 326 PM CDT Sun May 28 2017

Weak cold front was moving southeastward through southeastern MO and
southwestern IL this afternoon.  Still getting isolated showers
along and just behind this front in southeast MO and southwest IL,
and ahead of a northwest flow shortwave dropping southeastward
through our area.  Any showers should dissipate or shift southeast
of the forecast area by early evening with continued clearing of the
sky. Cooler conditions are expected tonight with good radiational
cooling due to a clearing sky, surface winds becoming light, and
relatively low surface dew points late tonight.  Although it will be
cooler tonight, the lows will only be a couple of degrees below
normal for late May.  Another northwest flow shortwave and an
associated weak cold front may bring a few showers or thunderstorms
to parts of our area Monday afternoon.  Despite increasing cloud
cover on Monday, highs will be warmer across southeast MO and
southwest IL ahead of the cold front.

GKS

.LONG TERM...  (Monday Night through Next Sunday)
Issued at 326 PM CDT Sun May 28 2017

The synoptic pattern at the start of the long term period will
feature a broad trough across much of the central CONUS into the
Great Lakes region.  This regime will largely persist through the
period, keeping northwest flow in place through much of the
extended.

Tuesday will be mostly dry during the daylight hours, but a few
showers and thunderstorms may creep into portions of
northern/central MO through the evening and overnight hours as a
warm front attempts to lift northward through the area.

The front should settle to the south of the area on Wednesday,
keeping the region dry.  However, Thursday into the upcoming weekend
will feature the front lifting back north of the region.  This will
allow for warmer and more unstable conditions to return, bringing
with it the chance for scattered showers and thunderstorms.
Temperatures Tuesday and Wednesday will be fairly seasonal (in the
upper 70s to low 80s) with low humidity values, but as the front
lifts back north the humidity will increase on Thursday into the
weekend with highs climbing back into the 80s.

KD

&&

.AVIATION...  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1127 AM CDT Sun May 28 2017

A weak cold front extending from a surface low over southwestern
MI southwest through the St Louis metro area will continue moving
southeastward. There were some isolated, post frontal showers
across west central IL late this morning ahead of a weak upper
level disturbance. Could not rule out a few light showers in the
St Louis metro area early this afternoon. The stratus clouds in
the St Louis metro area should clear out early this afternoon as
drier air advects into the region with only some mid level clouds
remaining. A clear sky is expected tonight with some mid-high
level clouds moving in Monday morning ahead of another upper
level disturbance and associated weak cold front. West-northwest
surface winds should become light later this evening as they back
around to a southwest direction.

SPECIFICS FOR KSTL: A weak cold front extending from a surface low
over southwestern MI southwest through the St Louis metro area
will continue moving southeastward. There were some isolated, post
frontal showers across west central IL late this morning ahead of
a weak upper level disturbance. Could not rule out a few light
showers in the STL area early this afternoon. The stratus clouds
in the St Louis metro area should clear out early this afternoon
as drier air advects into the region with only some mid level
clouds remaining. A clear sky is expected tonight with some mid-
high level clouds moving in Monday morning ahead of another upper
level disturbance and associated weak cold front. There may be a
few showers in the STL area Monday afternoon. West-northwest
surface winds should become light later this evening as they back
around to a southwest direction.

GKS

&&

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

$$

WFO LSX


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