Severe Thunderstorm Warning 292, NWS Sioux Falls, SD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
156 PM CDT Sat Aug 27 2022

.SHORT TERM...(This Evening through Sunday)
Issued at 150 PM CDT Sat Aug 27 2022

KEY MESSAGES:
1. Convection risks linger this afternoon, low end severe risks.
2. Much warmer Sunday, with severe convection possible late aftn.
3. An extended period of warm and dry weather through next week.

THIS AFTERNOON: Mid-lvl shortwave evident across eastern Nebraska on
both satellite and radar data this afternoon.  Scattered high based
showers and thunderstorms will persist across portions of eastern
SODAK this afternoon, with more focus turning towards eastern
Nebraska and western Iowa. Temperatures continue to slowly rise
into the middle 80s, with a narrow wedge of 70+ dew points along
the eastern periphery of the CWA. However, fairly widespread thick
mid- lvl clouds continue to spread eastward, which may slow down
the potential development in NW Iowa after 3pm. Eventually though,
strong DPVA will arrive and should kick off scattered
thunderstorms in an area of enhanced low-lvl lapse rates. The
greatest severe weather risk will be confined to an area along and
east of Highway 60, where MLCAPE between 800-1200 J/KG may be
possible and less inhibition is expected. Effective shear remains
on the weaker side, with most of the shear towards the upper
portions of the soundings. Threats with storms are likely more
focused towards a few strong wind gusts given 600+ J/KG DCAPE,
hail may tend to smaller side given the high freezing levels and
weaker shear. The heavy rain risks have likely shifted further
southeast into Iowa this evening, but a quick half inch to inch of
rain could be possible in a thunderstorm.

TONIGHT: Convection slides east of the CWA fairly quickly this
evening, leaving clearing skies into Sunday morning.  Have lowered
temperatures slightly further west, though winds will be quite mixy
through the night. Patchy valley fog could be possible.

SUNDAY: A stronger mid-lvl trough dips into the Northern Plains on
Sunday, pushing a surface cold front eastward through the day. Ahead
of this boundary, temperatures will climb well into the 80s and even
90s in some areas south of Interstate 90s. Winds are also expected
to be quite gusty, and have nudged towards the 90th percentile of
the NBM ahead of the boundary.

Low- lvl moisture advection in addition to evapotranspiration
effects will push surface dew points into the lower 70s in
portions of SW Minnesota into NW Iowa. This will lead to moderate
to high instability (3000-4000 J/KG) building along and east of
I-29 in the afternoon. Considerable inhibition will prevent
convection from forming for much of the afternoon, but as deeper
synoptic lift intersects the surface front after 4pm, convection
should develop very quickly. Initial storms may form over far NE
South Dakota, then begin to form southward along the advancing front
into SW Minnesota by 5pm. There is much more uncertainty on just
how far south convection may form along the boundary into Iowa and
Nebraska, as the greatest DPVA will be shifting northeast away
from the area and surface convergence along the front will be
weaker in these areas. It is possible current slight risk could
expand further south if CAMS indicate more development. Given high
degree of instability and slight increase in shear, a few
supercell and multicell clusters may form with very large hail and
strong wind surges. The good news is that unless the front slows,
the overall risk to the CWA may only be 1-3 hours.

.LONG TERM...(Sunday Night through Saturday)
Issued at 150 PM CDT Sat Aug 27 2022

MONDAY-FRIDAY: A brief cooldown is anticipate to start the new work
week as low-lvl cold advection drops temperatures into the 70s and
lower 80s.  That cool down will be brief as the synoptic pattern
suggests an extended period of dry and warmer than normal
temperatures.  Mid-lvl heights begin to rise through the week, and
other than a low potential for a small weakness in the ridge to pass
through Thursday, precipitation won't be more than sprinkles for
most of the Northern Plains.  The return of warmer southwesterly low-
lvl flow by Wednesday will trigger an increase in high temperatures,
and have favored the slightly warmer ECMWF/GFS over that of the NBM
in the extended. In fact, the multi-run trend of the ECMWF
ensemble continues to increase the potential highs later in the
week. The means highs likely back above normal into next weekend.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1213 PM CDT Sat Aug 27 2022

Mid-lvl energy moving through will continue to produce widely
scattered showers and thunderstorms into the afternoon. However
VFR conditions will continue in most areas.

A more concentrated area of showers and thunderstorms moves east
out of Nebraska by mid-afternoon, leading to greater probabilities
of lowering ceilings and visibility in NW Iowa and southern
Minnesota into early evening. Ceilings may remain at VFR levels
into the evening with this activity, though very brief visibility
restrictions may be possible.

VFR conditions continue into Sunday morning as winds remain
breezy.

&&

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

SHORT TERM...Dux
LONG TERM...Dux
AVIATION...Dux

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
452 AM CDT Sat Aug 27 2022

IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097-
098-281000-
Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Lincoln-Murray-Cottonwood-Nobles-Jackson-
Pipestone-Rock-
452 AM CDT Sat Aug 27 2022

This Hazardous Weather Outlook is for northwest Iowa, west central
Iowa and southwest Minnesota.

.DAY ONE...Today and tonight.

Isolated light showers are possible through the morning
hours today. Chance for showers and storms, some of which could be
strong to severe, increase later this afternoon and evening. While
widespread severe weather is not expected, large hail up to the size
of quarters and damaging winds to 60 mph are possible with the
strongest storms.

Along with the severe weather threat, locally heavy rainfall is
possible. Amounts are most likely to span between a quarter to three
quarters of an inch but locally higher amounts are possible.
Portions of northwest Iowa have the highest potential for locally
heavy rainfall.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Another round of strong to severe storms is possible on
Sunday. If storms are able to develop, large hail and damaging winds
will be the main hazards to be wary of.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

NEZ013-014-SDZ038>040-050-052>071-281000-
Dixon-Dakota-Beadle-Kingsbury-Brookings-Gregory-Jerauld-Sanborn-
Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook-Minnehaha-
Charles Mix-Douglas-Hutchinson-Turner-Lincoln-Bon Homme-Yankton-Clay-
Union-
452 AM CDT Sat Aug 27 2022

This Hazardous Weather Outlook is for northeast Nebraska, central
South Dakota, east central South Dakota, south central South Dakota
and southeast South Dakota.

.DAY ONE...Today and tonight.

Isolated showers and weak storms are possible throughout the day
today. Severe weather is not expected.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
600 PM CDT SAT AUG 27 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0555 PM     TSTM WND GST     4 WNW SPENCER           43.17N 95.22W
08/27/2022  M66 MPH          CLAY               IA   ASOS

            ASOS STATION KSPW SPENCER MUNICIPAL AIRPORT.

&&

TRM