Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 191715
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1215 PM CDT Thu Jul 19 2018

.SHORT TERM...(Today and Tonight)
Issued at 350 AM CDT Thu Jul 19 2018

Models continue to trend towards slowing the timing of the low
pressure system tracking across the northern Plains today and
tonight. The low is presently centered near Aberdeen and will slowly
track southeast to north of Watertown by midday, to near Jackson
Minnesota by early evening. Expect the showers and storms slowly
lifting northeast in east central SD and southwest MN to continue to
produce locally heavy rainfall and pose flash flooding concerns -
mainly in urban areas over the next few hours. Additional scattered
showers and storms will continue to redevelop mainly along and east
of the James River throughout the day today and the low center
slowly clips forecast area this afternoon and evening. Activity
will slowly diminish this evening, with a few showers lingering into
the early morning hours in southwest Minnesota.

Lowered high temperatures slightly in southwest Minnesota and
adjoining counties where clouds and precipitation will be more
prevalent. This will lead to a fairly large range in high
temperatures, with the 80s near the Missouri Valley where conditions
will remain largely dry with a greater deal of sunshine, with the
70s elsewhere.

The severe weather threat remains very low with limited shear and
instability across much of the area. Shear increases some in
northwest Iowa and far southern Minnesota, where a little more
sunshine could also help destabilize conditions some, possibly
supporting an isolated strong storm or two this afternoon, but think
that activity will be largely sub-severe. Main threats will be
locally heavy rainfall, but small hail and gusty winds will be
possible.

.LONG TERM...(Friday through Wednesday)
Issued at 350 AM CDT Thu Jul 19 2018

The upper low continues to slowly exit into the western Great Lakes
on Friday, leading to cooler northwest flow aloft. We should see
enough instability develop in the daytime for scattered to isolated
showers to pop up along with partly to mostly cloudy skies across
southwest Minnesota and east central South Dakota in the afternoon.
Otherwise, skies will be mostly clear to partly cloudy with highs in
the mid 70s to mid 80s.

Upper ridge continue to rebuild over the Rockies and high Plains
Friday night into Saturday. Saturday will see pleasant temperatures
in the upper 70s to mid 80s, with mostly clear skies, and relatively
light winds.

Upper low in central Canada attempts to top the ridge early next
week, sending a wave into central SD Sunday afternoon and evening.
Scattered storms will be possible west of the James Sunday afternoon
and evening, then spread eastward across the forecast area overnight
into midday Monday with an advancing front.

Pattern transitions to a quasi-zonal or northwest flow pattern
Tuesday and beyond. The active pattern directs the next chance for
showers and storms on Tuesday night into Wednesday. Cooler than
normal temperatures will persist during with period with highs in
the mid 70s to lower 80s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1213 PM CDT Thu Jul 19 2018

Showers and isolated thunderstorms will remain a possibility
mainly over southwestern MN and portions of northwestern IA
through the afternoon. Otherwise, slowly improving ceilings with
northwesterly winds gusting to around 30 kts at times into early
this evening.

&&

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

$$

SHORT TERM...
LONG TERM...
AVIATION...JM


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