Area Forecast Discussion
Issued by NWS Springfield, MO

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FXUS63 KSGF 251652
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
1152 AM CDT Thu May 25 2017

.SHORT TERM...(Today and tonight)
Issued at 142 AM CDT Thu May 25 2017

Quiet start to the forecast. A N-S oriented sfc ridge over MO
with lots of dry air aloft will make for a nice morning except for
fog near lakes and low spots early. The Branson West Airport has
dense fog already, and this should be indicative of lake areas
over the region. The sfc ridge moves off to the east today with
winds backing to the south. It will be a nice warmup after a cool
start.

For tonight: Lee side low pressure over the High Plains region
will move into western OK late tonight. Low level moisture will
be drawn northward underneath an elevated mixed layer (eml)
advecting into our area. Could see some stratus move northward
where the better low level moisture axis exists over eastern
OK/far western AR, moving into western cwfa toward the end of, or
just after this period Fri morning.

.LONG TERM...(Friday through Wednesday)
Issued at 221 AM CDT Thu May 25 2017

Saturday looks like a potentially active/higher end thunderstorm impact
weather day, especially considering it is the beginning of a
holiday weekend.

Friday-Friday night: Sfc low pressure over OK early will continue
to shift slowly east and northeast with a sfc trough expected to
become sw-ne oriented from se KS into central MO by late in the
day. Strong capping early is expected to weaken by late in the day
from combination of sfc heating and a slight cooling of the warm
nose aloft. MUCAPES/MLCAPES on the order of 4000 j/kg with strong
cape/instability through the hail growth zone with steep mid
level lapse rates and about 45kts 0-6km bulk shear would lead to a
higher end large hail threat and damaging winds IF (a big IF) the
cap can break. Convergence along the sfc boundary could be a
trigger. The ECMWF is the most robust of the global models with
the convective development, while the GFS, NAM, and GDPS are
nearly dry. In any case, later in the night a strengthening low
level jet may trigger additional somewhat elevated convection, but
again it will be conditional on whether or not capping will hold.
Still have low confidence in how things will evolve Fri-Fri
night, but storms that can develop will have severe potential.

Saturday-Saturday night: A stronger sfc front will eventually push
the area. While the waters may be muddied somewhat if Friday night
convection develops and lingers early in this period, almost all
guidance indicates very strong instability Saturday afternoon
either weakly capped or uncapped by late in the day. Storm timing
is a little up in the air, but afternoon/evening seem to be the
time guidance is focused on for severe storm development. Large
hail and damaging winds are expected to be the main risks,
potentially higher end risks. It is worth noting that hail
occurrence analogs show the potential for very large/giant hail
given the progged vertical instability and shear profiles.
Supercells are expected to grow upscale into a linear type MCS
with time Saturday evening/night. A tornado risk will exist, but a
veered low level sw wind will not favor a large scale risk.
Localized boundaries and storm scale interactions will lead to
some tornado potential. Pockets of heavy rainfall/flooding will be
possible, but a large scale/lengthy flooding threat is not
expected. However, we will still need to monitor hydrologic
conditions given higher than normal water and soil moisture levels
from recent rains.

Sunday: Some activity may linger early Sunday, but in general
activity is expected south of the area with drier air moving in.

Memorial Day Monday: Looks quiet with somewhat gusty wnw daytime
winds.

Tuesday-Wednesday : Guidance varies, but a nw flow aloft Tue may
push a sfc trough through the region. At this point, nothing
notable. The front may hang up south and west of the area Wed with
some modest rain chances as the pattern transitions back to a w-sw
flow aloft.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1147 AM CDT Thu May 25 2017

Upper level ridge was building into the area late this morning
with a southerly wind becoming established at the TAF sites on the
back side of a surface area of high pressure. A clear sky will
remain in place across the area through the remainder of the
daylight hours today. A low level jet will strengthen on the
southeast flank of a developing area of low pressure across the
high plains. This will lead to some low level wind shear from
around mid evening through the overnight hours. As the surface
wind backs tonight, SGF will be in a favorable direction for
upslope channeling and have added gustiness to the TAFS there.
Could see some stratus moving into the area as low level moisture
increases overnight and on Friday morning, but expecting VFR
through the period.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

SHORT TERM...DSA
LONG TERM...DSA
AVIATION...Lindenberg



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