Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 152316
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
616 PM CDT Thu Jun 15 2017

.SHORT TERM...(Today and Tonight)
Issued at 309 PM CDT Thu Jun 15 2017

Quasi-zonal flow will continue tonight and Friday as an upper low
moves slowly eastward across south central Canada. Currently,
satellite is showing a short wave moving eastward primarily across
Nebraska, however the convection is breaking out further south in
central KS along the primary warm front. What appears to happen
in our area, is a weak wind shift will move slowly eastward very
late tonight and Friday along the far southern periphery of the
aforementioned upper low to the north. An elevated warm front with
850-700mb thetae advection may spark a few elevated, accas type
TSRA along the I 90 corridor and slightly northward very late
tonight. Following the thetae advection, this could linger in our
eastern zones Friday morning. But again, any showers or TSRA look
to be very skittish. Then on Friday afternoon as the surface and
low level wind shift moves eastward, more TSRA is possible under
moderate instability across the eastern and southeastern zones,
but with very weak wind shear in the lowest 1.5km. Mid level winds
are decidedly westerly in the 30 to 40 knot range. So there could
be a few TSRA popping along and ahead of the wind shift as the
atmosphere does not look capped. In fact, 700mb temperatures are
averaging +6 to +8C from north to south.

This time around, blended temperatures did not look too bad given
the thermal profile in the low levels. Fridays highs will be in the
85 to 90 degree range despite a fair amount of mid and high
cloudiness, especially in the morning. Dew point values are not high
giving only moderate levels of humidity.

.LONG TERM...(Friday through Wednesday)
Issued at 309 PM CDT Thu Jun 15 2017

Upper level wave drops through foecast area on Saturday with
associated surface front. Should be enough instability around the
area to pop a few thunderstorms in areas of northwest Iowa and
northeast Nebraska Friday night into Saturday. SPC outlook has a
slight risk of severe weather in the area, but at this point I
feel the best chances of severe weather will be to south of the
Sioux Falls forecast area. Scattered rain showers should continue
through most of the early afternoon hours on Saturday, especially
in northwest Iowa. But as front continues to sag south, whatever
instability is left over will be taken with it.

Main story after that is the cooler weather on Father`s Day. High
temps look quite a bit below normal. Question was whether or not
to include a chance for widely scattered showers. Feel I couldn`t
rule it out, so decided to leave them in the grids. After Sunday,
the work week looks pretty quiet. Temperatures will slowly rebound
before another front passes through late in the week knocking
temperatures down into upper 70s to lower 80s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 544 PM CDT Thu Jun 15 2017

VFR conditions expected through the period. Small chance of
showers at FSD and SUX Friday morning and a small chance for
thunder at SUX Friday afternoon. Chances are small enough to
preclude mentions in the TAF. Otherwise, light winds will veer
around from northwest, to southeast, and back to northwest by the
end of the period.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&

$$

SHORT TERM...05
LONG TERM...08
AVIATION...Dux/Ferguson



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