Area Forecast Discussion
Issued by NWS Sioux Falls, SD

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41
000
FXUS63 KFSD 270408
AFDFSD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1108 PM CDT Mon Jul 26 2021

.SHORT TERM...(This Evening through Tuesday)
Issued at 247 PM CDT Mon Jul 26 2021

Very warm and moderately humid conditions will continue tonight into
Tuesday. A weak wave will skirt southwest MN and could allow some
showers and thunderstorm activity in that area, but confidence is
very low on this happening. Will basically keep the small chances
along and east of the Buffalo Ridge. Otherwise southerly winds will
only allow temperatures to drop into the upper 60s to lower 70s
overnight.

The heat really builds into the area on Tuesday as a more
significant upper level jet max builds into the US/Canadian border.
This should support highs of about 100 or a couple degrees higher
along and west of the James, with mid and upper 90s to the east.
Overall looks like smoke aloft will not play a big role in
temperatures on Tuesday. As for convective chances they will be
little to none. A few model soundings do hint at breaking the cap at
the expense of drying out the low levels and obliterating the
instability, but would still be enough for a couple of weak
updrafts. Not enough to add to the forecast and likely nothing that
would become severe. Will maintain the heat advisory for Tuesday.

.LONG TERM...(Tuesday Night through Monday)
Issued at 247 PM CDT Mon Jul 26 2021

Tuesday night into Wednesday will see the heat further build into
the area. Winds will remain southerly at night which should support
low sin the lower to mid 70s most locations. As the upper level jet
max shifts east it will drag a weak front south which will provide
the area with some enhanced mixing as the low level winds turn more
westerly. While a late afternoon thunderstorm will be possible, it
is highly unlikely with a capping inversion likely in place, even
with highs in the 100s in many locations. Will continue with the
excessive heat watch.

By Wednesday night the front will sag south into the area and may
serve as a focus for isolated thunderstorms. With the potential for
quite a bit of dry air in the low levels a south or southwest
progressing cold pool could allow for some strong wind gusts if
thunderstorms can get going.

Thursday will be dry and seasonally hit with highs in the mid 80s to
lower 90s. The chances for thunderstorms are very low.

Thursday night into Saturday the upper level ridge appears to
sharpen to the west which puts the area on the backside of the
trough pushing east. This may give us a slightly better chance for
showers and thunderstorms. Too early to get real excited about but
this will be a time to watch.

Sunday into Monday should be dry with seasonally warm conditions as
high pressure at the surface shifts east. Lows generally in the 60s
and highs in the 80s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1108 PM CDT Mon Jul 26 2021

Just shy of needing a few hours mention of low-level wind shear
tonight for KHON/KFSD/KSUX, but fairly marginal at this point as
likely surface winds are a bit underpredicted. Winds could be
briefly gusty in the morning as this off-surface gradient mixes
into the PBL, but should even out to lighter values by midday.
Looks fairly capped, and any minor convective threat should be
after 00z/28 toward southwest MN.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory from noon to 9 PM CDT Tuesday for SDZ038>040-050-
     052>071.

     Excessive Heat Watch from Wednesday afternoon through Wednesday
     evening for SDZ038>040-050-052>071.

MN...Heat Advisory from noon to 9 PM CDT Tuesday for MNZ071-072-080-
     081-089-090-097-098.

     Excessive Heat Watch from Wednesday afternoon through Wednesday
     evening for MNZ071-072-080-081-089-090-097-098.

IA...Heat Advisory from noon to 9 PM CDT Tuesday for IAZ001>003-
     012>014-020>022-031-032.

     Excessive Heat Watch from Wednesday afternoon through Wednesday
     evening for IAZ001>003-012>014-020>022-031-032.

NE...Heat Advisory from noon to 9 PM CDT Tuesday for NEZ013-014.

     Excessive Heat Watch from Wednesday afternoon through Wednesday
     evening for NEZ013-014.

&&

$$

SHORT TERM...08
LONG TERM...08
AVIATION...Chapman


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.