Area Forecast Discussion
Issued by NWS Springfield, MO

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829
FXUS63 KSGF 280741
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
241 AM CDT Fri Apr 28 2017

.SHORT TERM...(Today through Sunday Morning)
Issued at 240 AM CDT Fri Apr 28 2017

No major changes to the overall message this morning, with a
potentially significant flood event still on track to affect the
region starting tonight. While the exact location of the heaviest
rainfall remains somewhat in question, confidence is high that
most of the area will experience 4-6" of rain by Sunday afternoon.

Starting out this morning, an area of light rain is moving across
the region ahead of a lead shortwave traversing the area. This
rain should end from west to east later this morning into the
early afternoon hours. Southerly winds will remain fairly steady
today, helping to bring a moisture-rich airmass into the area by
tonight.

A warm front will lift north toward the region during the day
today, and will push north to around I-44 late tonight before
stalling out. Numerous thunderstorms are expected to develop
along this front during the mid to late evening hours coincident
with an increasing low level jet. With plenty of instability and
shear in place, there will be a risk for severe weather with these
thunderstorms. The bulk of the severe weather threat tonight
should be in the form of large hail, as much of the convection
will be elevated in nature. That said, should a few storms develop
far enough into the warm sector to become surface based, there
will be an attendant wind and tornado threat given very favorable
instability and shear profiles. With the zone of isentropic ascent
expected to continue through the night across the area, multiple
waves of thunderstorms are likely into Saturday morning.

Along with the severe weather threat mentioned above, very heavy
rain remains an obvious concern going into the overnight hours
tonight. PWAT values are expected to approach record levels for
April (~1.70") along and just south of the frontal boundary.
Multiple waves of deep convection have the potential to bring
several inches of rain in a very short period of time to some
areas, posing a potentially significant flash flood risk. The
latest model guidance does suggest a slight northwestward shift to
the axis of heaviest rain, moving the area of greatest concern to
along the I-44 corridor, as opposed to south of. Ultimately, with
soils almost completely saturated already, flood issues will
likely be rather widespread regardless of where exactly the
heaviest rain falls.

On Saturday, the frontal boundary may lift just a bit further
north during the day, but widespread thunderstorm activity should
still affect most, if not all of the forecast area during the day
Saturday into Saturday night. There will also be an ongoing risk
for severe weather along and south of the front, where instability
will be highest. Severe convection will likely take the form of
embedded line segments, though a few supercells are also possible.
Large hail, gusty winds, and perhaps a tornado or two are all
possible.

Much of the forecast area should see between 4 and 6 inches of
rain by the time things start to taper off on Sunday. Where
convection trains the most (just along the frontal zone), amounts
in excess of 8" are a decent bet. It is important to note as well
that deep convection will have the potential of bringing several
inches of rain to localized areas in a very short period of time,
which would result in enhanced flash flood risks where this
occurs. This will be a short term forecast challenge Friday night
through Saturday, so it will be important to remain alert for
forecast updates, along with any flood/flash flood warnings that
are issued.

In addition to the flash flood risk, early indications are that
many area rivers will reach flood stage, with many locations
reaching at least moderate, and perhaps major flood stage. Those
with interests along area rivers are encouraged to remain alert
through the weekend.

.LONG TERM...(Sunday Night through Thursday)
Issued at 240 AM CDT Fri Apr 28 2017

Rain will begin to end by Sunday night, though a few light showers
and/or areas of drizzle may continue into Monday as the upper low
remains in the area. Lows Sunday night look to fall into the
upper 30s or low 40s. Highs will remain cool on Monday, with
temperatures in the 50s.

Northwest flow is expected to persist for much of the week,
keeping temperatures below average. There will be another chance
for rain Tuesday night through Wednesday as a shortwave dives
south through the region.

Upper level ridging is then expected to build back in to close out
the week, suggesting drier and warm conditions heading into next
weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1150 PM CDT Thu Apr 27 2017

Pilots can expect deteriorating flight conditions at area
terminals as we head into the overnight hours and Friday. Showers
will increase from the west tonight with lowering ceilings toward
morning into Friday. MVFR conditions are expected to develop
Friday as ceilings continue to lower. Showers and thunderstorms
will develop later Friday night with MVFR conditions persisting.


&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Flash Flood Watch from this evening through Sunday evening for
     MOZ055>058-066>071-077>083-088>098-101>106.

KS...Flash Flood Watch from this evening through Sunday evening for
     KSZ073-097-101.

&&

$$

SHORT TERM...Boxell
LONG TERM...Boxell
AVIATION...Foster



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