Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 281642
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1142 AM CDT Fri Jul 28 2017

.SHORT TERM...(Today and Tonight)
Issued at 230 AM CDT Fri Jul 28 2017

Surface high pressure centered over the western Great Lakes region
will dominate our weather for today and tonight. Winds will take on
a more southeasterly component during the day as the high settles
to the south, but remain light through the afternoon. Will see mid
and high clouds stream across the region, and temperatures will be
similar to yesterday - in the lower to mid 80s.

Tonight will continue to be quiet with a few mid clouds continuing
to slide across the area. Models do develop convection over north
central Nebraska overnight with a strengthening low level jet and
upper level support provided by a jet streak over southern
SD/northern NE. While think this activity will for the most part
remain off to our west, cannot completely rule out an isolated
shower/thunderstorm making it into our far south central SD zones
after 06Z. Overnight temperatures will be seasonable, in the lower
to mid 60s.

.LONG TERM...(Saturday through Thursday)
Issued at 230 AM CDT Fri Jul 28 2017

With upper level ridging extending across the intermountain west to
southern plains this weekend, the northern plains will be under a
light northwest flow aloft. High pressure at the surface just east
of this area will continue to greatly influence our weather with
seasonal temperatures. This high has effectively blocked the gulf,
all the way through west Texas, therefore humidity values will not
be very high either despite a south to southeast flow of surface
air. A very weak short wave could affect the forecast area Saturday
night and Sunday. There is a decent amount of moisture in the 850-
700mb layer. However the GFS is the most robust in showing this
feature with various other models even weaker with the wave.
Therefore only very skittish pops are warranted the latter half of
the weekend.

By Tuesday, the upper ridge migrates completely to the western U.S.
again. A short wave dives down the northwest flow aloft to our
northeast Tuesday and Tuesday night. There is some consensus in
bringing a frontal boundary through Tuesday night with this wave.
But again with little in the way of organization with the dynamical
regime, chances for TSRA just do not look very high at this time
Tuesday night. Did warm up the highs on Tuesday just a little bit
above superblend, albeit the GFS 850mb temperatures are likely too
warm. But doing this shows a trend of slightly cooler weather for
Wednesday. Highs next week look to continue in the 80s, except for
around 90 in our south central SD zones. So all in all temperatures
continue to look rather seasonal.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1140 AM CDT Fri Jul 28 2017

VFR through the period. A few sprinkles today and possibly again
on Saturday. Might be just enough instability and moisture
Saturday afternoon and evening for a shower or isolated
thunderstorm.

&&

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

$$

SHORT TERM...JM
LONG TERM...MJ
AVIATION...08


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