Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Springfield MO
103 PM CDT sun Apr 19 2015

..thunderstorm development expected this afternoon...

Mesoscale discussion...
issued at 1245 PM CDT sun Apr 19 2015

An upper level trough is pushing east across Kansas early this
afternoon. Ahead of the the trough, a surface boundary will push east
across the Eastern Ozarks early this afternoon. A few thunderstorms
are developing long this boundary. Instability is currently
limited ahead of this boundary as showers and cloudy skies have
occurred across a lot of Eastern Ozarks this morning. Therefore no
severe weather is expected with this activity.

Behind this boundary winds have switched to the northwest and
dewpoints have drooped slightly. Breaks in the clouds are starting
to occur across southwestern Missouri behind the front pushing
east. As the upper level trough pushes east into the area later
this afternoon into this evening scattered thunderstorms will
develop. Instability will increase slightly this afternoon but
the decrease dewpoints will still keep instability on the limited
side. Height falls from the approaching trough will result in
colder temperatures aloft. Therefore storms will not have to grow
as tall to produce hail.

The limited instability will keep US from having a widespread
severe risk, but small hail will be possible with any storms that
develop this afternoon given the colder temperatures aloft. A few
of the stronger storms will be capable of hail to the size of
quarters and a possibly a few gust to around 60 mph, mainly across
far southern Missouri with the best instability. The better severe
potential will be just south of the area where better instability
will occur across Arkansas.

&&

Short term...(today and tonight)
issued at 346 am CDT sun Apr 19 2015

Slowed approach of mid and upper level clouds has allowed good
radiational cooling and the development of fog in between
the convective clusters over the west and eastern portions of the
County Warning Area. Clouds and early morning precipitation may delay the fog
burning off a tad...but visibilities will improve shortly after
the morning commute.

Overall forecast falling in line with previous thinking. Main
short term challenge tied to coverage of thunderstorm activity
this morning followed by potential for marginally severe storms
this afternoon.

Storms approaching from the west overnight have maintained an
outflow dominant structure that has lead to an overall easterly
development into far western MO at 08z as storms form along the
outflow boundaries then a general decrease in coverage due to the
lack of instability. A somewhat better concentration of showers
and a few weak thunderstorms associated with another vorticity
lobe over south central MO will also slowly drift northwestward
this morning as well.

Diffuse upper waves will pass through forecast area through
tonight leading to widespread showers and isolated
thunderstorms. Of note will be the main shortwave that crosses
southern MO late this afternoon into tonight. While signals exist
for some organized storms to the south of i44 given the 800-1200
MLCAPE as mid levels cool and 30-40 knots 0-6km shear...the amount of
cin a concern especially given the potential for showers during
the day ahead of the main wave. Main impact for any strong to low
end severe will be hail. Precipitation to then end west to east
tonight as upper low lifts northeast.

Long term...(monday through saturday)
issued at 346 am CDT sun Apr 19 2015

Zonal to weak northwest flow to dominate through midweek with the
potential for weak shortwaves to generate some light rain. More
significant precipitation is expected from Friday into the
weekend as another weakening closed low in the southern stream
approaches.

Clearing skies and light winds will result in a much cooler
temperatures Monday night. While widespread frost is not
expected...sheltered areas may see some middle 30s.

&&

Aviation...(for the 18z tafs through 18z Monday afternoon) issued at
1230 PM CDT sun Apr 19 2015

VFR conditions will continue for another hour or two at the
terminal sites. Isolated showers and thunderstorms will then move
into jln by mid afternoon and then sgf and bbg by late
afternoon/early evening. Best thunderstorm potential will be at
bbg this evening. Once showers and thunderstorms exit late this
evening a band of low clouds will move in creating MVFR conditions
through early tomorrow morning before clearing. While not included
in the tafs, there is a low potential for low level wind shear
overnight.

&&

Sgf watches/warnings/advisories...
MO...none.
Kansas...none.
&&

$$

Mesoscale...wise
short term...Runnels
long term...Runnels
aviation...Burchfield/Foster

National Weather Service Glossary of Abbreviations