Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 010240

940 PM CDT Sun May 31 2015

Issued at 940 PM CDT Sun May 31 2015

Upper LOW churning over extreme south-central MO this evening has
ejected an upper level disturbance to the northeast of the LOW
center, near KMDH in southern IL, and has resulted in light rain
with some measurable. The expected track of this disturbance
should follow the southeast edge of the CWA boundary in IL,
leaving little more than scattered sprinkles for areas along a
Salem (KSLO) to Farmington (KFAM) line. This is in line with the
current forecast.

This situation is expected to continue until late Monday morning
when the LOW finally pulls away.

Showers continue to form over the mid-MO valley from near a
genesis region near KFSD in southeast SD and while the prevailing
flow will try to push them down into our region, little support to
the southeast to sustain and sheer distance of travel should
prevent any impact in our CWA.

Otherwise, E-NE flow at cloud level should keep cloudy skies over
much of the region overnight and well into Monday. Look for a
minimal temp drop tonight with a somewhat better rise on Monday.
Higher MOS temps for mins tonight and lower MOS for maxes on
Monday preferred.



.SHORT TERM: (Tonight through Tuesday)
Issued at 310 PM CDT Sun May 31 2015

A cool weather pattern will persist for the next few days with
below average temperatures. A slow-moving upper trof located
through the middle and upper MS River Valley along with a
expansive high pressure system centered in southeast Canada will
be the controlling weather features. The surface high will maintain
northeasterly low level flow through Monday which will keep extensive
stratus locked in across the area, slowly clearing across the
northern CWA during the day on Monday. The upper trof will also
make us keep a close eye on southern sections for any precipitation
threat. Thus far the precipitation has remained south of the CWA,
and overall the HRRR and other few deterministic models which have
had precip into our CWA have been too far north. The influence of
the surface high should lessen a bit on Tuesday with the upper
trof axis moving to the east and the general thought is there will
be lesser low clouds as well.


.LONG TERM: (Wednesday through Next Sunday)
Issued at 310 PM CDT Sun May 31 2015

Newer model runs continue to show a pattern favorable for a warm-
up through the later part of the week, however the pattern has
greater thunderstorm potential as well. The southern stream upper
trof/low through the Gulf States will slowly progress east while
an upper trof deepens in the far western U.S. In the process an
upper ridge from the Plains will attempt to build into the area,
however the guidance is now suggesting weak impulses in the NW
flow on the east side of the ridge will bring increasing thunderstorm
chances along with and an east-west frontal boundary sagging into
the area late Friday-Saturday.



.AVIATION:  (For the 00z TAFs through 00z Monday Evening)
Issued at 533 PM CDT Sun May 31 2015

Rain associated with an upper level disturbance and an inverted
surface trough should remain s-se of the taf sites. The persistent
stratus cloud deck will continue at the taf sites with the
current ceilings around 2000 feet lowering to around 1000 feet
later this evening or overnight. The cloud ceiling will gradually
rise on Monday to around 2000-3000 feet Monday afternoon with some
breaks possible in UIN and COU by late afternoon.  N-nely surface
winds will become nely later tonight with a surface ridge
extending from MN and WI south into northeast MO shifting only
slowly eastward.

Specifics for KSTL: The cloud ceiling will lower tonight to around
1000 feet, then rise to around 2000 feet Monday afternoon. There
may be some breaks in the cloud deck Monday evening. Nly surface
wind will veer around to a nely direction later tonight.





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