Area Forecast Discussion
Issued by NWS Springfield, MO

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FXUS63 KSGF 240918

Area Forecast Discussion
National Weather Service Springfield MO
418 AM CDT Wed May 24 2017

.SHORT TERM...(Today and tonight)
Issued at 317 AM CDT Wed May 24 2017

An upper low centered over south central IA will move sse through
MO today. Will maintain chance for showers today. Could see a few
lightning strikes, primarily over the eastern half of the cwfa,
but severe storms are not expected,

A ridge of sfc high pressure will move into the western cwfa
tonight. A clear (or clearing) sky and light winds will produce
chances for shallow fog in low lying terrain and near lakes.

.LONG TERM...(Thursday through Tuesday)
Issued at 327 AM CDT Wed May 24 2017

Thursday: After a cool start, we will see a quick warmup with
winds backing to the west and southwest.

Thursday night-Friday night: The upper flow pattern shifts, with
the southern branch of a split flow pattern to affect our area.
Lee side sfc low development Thu will allow southerly low level
winds to bring moisture northward into the Plains. An elevated
mixed layer (eml) will also overspread the region late Thu night
into Fri. So despite, low level moisture advection, capping will
keep precip chances fairly low most of the day Fri, even with a
sfc front edging southeast into the area. By late afternoon-
evening Fri, capping may weaken sufficiently to allow convection
to develop as low level convergence develops with a nocturnal
850mb(ish) jet increases. Progged GFS soundings indicate steep
mid level lapse rates with the eml. Clusters of convection should
be elevated should they develop Fri evening/night with hailers the
main risk given the elevated instability/vertical shear combo.
Tstm winds would be a risk if the convection can grow upscale. Guidance
is quite variable on where/when/if convection will develop, and
even the GFS is only weakening the cap briefly early Fri night.
Any hazards are conditional on breaking the cap for this period.
Low confidence at this point.

Saturday-Saturday night: A stronger frontal boundary is expected
to move through our area during this time frame. Strong
instability progged from the GFS indicates mlcapes of 4000 j/kg
with 0-6km bulk shear 45-50kts. Capping early is expected to
weaken/break during the day. The air mass and vertical temperature
profile favor large hail/damaging winds. The low level winds look
to be veered to the sw ahead of the approaching front (fairly
unidirectional vertical profile) which doesn`t favor a higher
tornado threat in the absence of any smaller scale boundaries. The
only fly in the ointment here could be any ongoing convection
from Friday night (should it develop). However, taking everything
at face value, the severe storm set up looks favorable Saturday.
Will also monitor for heavy rain/flood potential, but for the most
part this front will move by fairly quickly.

Sunday: Some timing differences in the guidance shows some
indication of some possible lingering showers/tstms into early
Sunday over far southern MO. Otherwise, the northern branch of the
upper level flow will help push the frontal boundary off to the

Monday/Memorial Day-Tuesday: Looks quiet (overall). A large upper
level trough/low over the Great Lakes region will keep us in
cyclonic flow aloft and can`t rule out some showers/tstms Tue as a
shortwave moves southeast through the U.S. Midwest.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1154 PM CDT Tue May 23 2017

Upper level low pressure will continue to slowly move through the
region into Wednesday. Ceilings will lower late tonight with MVFR
likely by sunrise. MVFR is then expected for much of Wednesday,
although ceilings may improve into the VFR category over portions
of southern Missouri Wednesday afternoon. Scattered rain showers
are again expected from late morning into the afternoon as the
atmosphere becomes weakly unstable. Surface winds will increase
out of the northwest and become gusty during the day on Wednesday.




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