Area Forecast Discussion
Issued by NWS Springfield, MO
FXUS63 KSGF 162007
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
307 PM CDT Sat Aug 16 2014
.SHORT TERM...(This Evening through Tonight)
Issued at 306 PM CDT SAT AUG 16 2014
Main forecast concern will be with storm development and trends
for this afternoon through tonight. The cold front is making
slower than expected southward progress and currently extends from
Kirksville to Sedalia to Emporia Kansas. The airmass ahead of the
front has gotten very unstable with LAPS showing lifted indices
around -7 and CAPE over 3000 j/kg. Dewpoint temps in the lower to
mid 70s were pooling just ahead of the front. The latest radar
images shows storms beginning to develop just to the northwest of
the forecast area.
Storm coverage will increase ahead of the front through the rest
of the afternoon as the lower levels continue to destabilize and a
subtle 700mb trough moves across the area. Freezing levels will
remain high limiting hail growth potential. However unusually tall
CAPE profile on NAM Bufr soundings show that cloud heights may be
sufficient for at least some marginally severe hailstones. Steep mixed
layer below cloud height may also allow a few storms to produce
wind gusts to 60 mph. Am getting concerned about higher
precipitable water values showing up on forecast soundings so may
need to add limited flood potential to our HWO.
Storm development will gradually shift southeast through tonight
as the front makes its way toward the I-44 corridor...so will keep
pops going through the night. Severe threat should diminish with
loss of afternoon destabilization.
.LONG TERM...(Sunday through Saturday)
Issued at 306 PM CDT SAT AUG 16 2014
Short wave to exit eastward and approach LSX by 12z Sunday. On
going storms should be exiting region as well as front passes
through as well.
Weak ripples currently topping the upper ridge and then descending
into the plains to then be key for redevelopment of thunderstorms over
the eastern CWA on Sunday and then again on Monday. While POPS are
in the forecast...confidence in any organized rain is somewhat
limited after tonight into early next week.
Models then advertise a series of shortwaves to travel across the
northern tier of the nation...with variation in how they are
handling a split flow. Of particular interest is a stronger wave
that both the GFS/ECM advect across the northern tier to reach the
Great Lakes on Wednesday. There is the potential that this wave
will push a weakening front into the Central Plains that will
focus convergence as weak ripples top the ridge. At this time
though...will downplay rain chances while noting that some of the
warmest conditions of the summer will occur as the ridge builds
into the Central Plains.
The fact that this summer has been unclimatological mild will
potentially magnify the impact of the situation when combined with
an open Gulf and as school resumes and fall sports continue to
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1216 PM CDT SAT AUG 16 2014
We will see a cold front move across the Joplin and Springfield
airports during this forecast period...with winds shifting to
west and eventually northwest during the latter part of the
forecast period. With atmosphere destabilizing ahead of the
approaching front will carry vicinity thunder from mid afternoon
through much of the evening. For now will only carry tempo group
at Springfield where most likely storm development is expected.
We have also included light MVFR fog at all airports after 09Z
with MVFR ceilings at Springfield and Joplin due to proximity to
upper low toward the end of the forecast period.