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fxus63 kfsd 192050 

Area forecast discussion
National Weather Service Sioux Falls South Dakota
350 PM CDT Wed Jun 19 2019

Short term...(this evening through thursday)
issued at 347 PM CDT Wed Jun 19 2019

Shortwave diving into eastern South Dakota this evening will
continue to produce widely scattered showers or sprinkles mainly
across southeast South Dakota. High res models such as the hrrr and arw have
also started to point towards additional scattered showers and
thunderstorms forming late afternoon and this evening in south
central along the low level frontal boundary. Shear is expected to
continue to increase this evening in south central, however with
cloudy skies today, instability is limited. Model soundings depict
elongated, skinny elevated cape values of around 500 to 1000 j/kg.
Could see a few stronger storms with small hail and gusty winds, but
the overall severe threat is low. One thing to watch: given the
earlier reports of a landspout with this activity in Todd County,
will need to watch for pockets of low level vorticity along the
boundary as it moves into our western border. Landspout threat
overall is very low.

Shortly after sunset, models weaken any thunderstorm activity, with
a few isolated showers and storms remaining possible in southeast South Dakota
into the early morning hours. Last tonight a stronger wave tracks
eastward across the Dakotas, bringing a better threat for showers
and thunderstorms late tonight through the day on Thursday. Activity
will be mainly focused west of I-29 in the morning, and to the east
midday into the afternoon. Strong shear and weak to modest elevated
instability will keep a marginal threat for strong or severe storms
in the morning. Instability increases in the afternoon in northwest
Iowa and northeast Nebraska which could materialize to a greater
threat for afternoon severe storms with hail to the size of half
dollars and wind gusts to 65 mph as the main threat.

Long term...(thursday night through wednesday)
issued at 347 PM CDT Wed Jun 19 2019

Active summertime weather pattern will direct several waves into the
region headed into early next week as the upper pattern shifts
towards southwest flow. Very slow moving upper level trough digs
southward into the Great Basin Thursday night and Friday, stalling
over the intermountain west this weekend.

For Thursday night, the next shortwave lifts across the northern
plains, with a warm frontal boundary potentially serving as the
catalyst for the next severe threat. Mid level warm air advection
however will surge northward into the I-29 corridor and eastward
late Thursday night into Friday. The main concern will be the
location of the surface and elevated boundaries and how the ongoing
convection Thursday night into Friday will impact these boundary.
Steep mid level lapse rates (8+), cape values greater than 2000
j/kg and bulk shear values greater than 40 kts will be possible
south of the warm front in the afternoon, but the question will be
how far north this front reaches and whether convection earlier
in the day/overnight will impact profiles. If conditions become
maximized, large hail, and damaging winds will be possible across
mainly the eastern half of the forecast area. Cannot rule out an
isolated tornadic threat near the warm front as well if surface
based storms develop. In less optimal conditions with limited
instability and without the boundary interaction, elevated
stronger or marginally severe storms are expected.

Additional scattered showers and storms continue overnight Friday
into Saturday morning, lingering into the afternoon east of I-29.
The next wave lift into the Central High plains on Sunday, with yet
more scattered showers and thunderstorms lifting northward through
the region.

Early next week northwest flow aloft transitions to a more zonal or
weak ridging pattern, however models show some fairly significant
timing differences. The pattern should bring warmer temperatures
along with much lower precipitation chances.


Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 1250 PM CDT Wed Jun 19 2019

Scattered high-cloud-based rain showers will move through the
region this afternoon. Radar imagery shows light precipitation
near khon and kmhe moving east, but much of this is likely not
reaching the ground. Lightning is not likely with this activity
along and east of I-29 due to limited atmospheric instability,
but a few storms capable of lightning are possible west of kmhe
during the evening. Winds remain light through the afternoon and
overnight hours. More widespread showers and thunderstorms will
move west to east across the region after sunrise Thursday


Fsd watches/warnings/advisories...
South Dakota...none.


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