River Flood Warning 334, NWS Sioux Falls, SD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
623 AM CDT Mon Oct 21 2019

.SHORT TERM...(Today and Tonight)
Issued at 346 AM CDT Mon Oct 21 2019

The main weather concerns today are very strong winds and scattered
rain showers.

Early this morning, the strong upper low was located over south
central SD/east central NE. However, most of the area is
positioned under a dry slot with little if any precipitation. The
exception is across our far eastern counties in Minnesota and
northwest Iowa where light rain continues to move through.

Additional showers are expected as the main upper low slowly swings
east-northeast into the Upper Mississippi Valley/Great Lakes area
today. This will result in off and on light rain showers on the back
edge of the system. Forecast soundings suggest well-saturated
profiles through most of the day; therefore rain chances increase
by late morning and will continue through the evening. While
instability remains limited through the period, a few rumbles of
thunder cannot be ruled out this afternoon. Rain will gradually
diminish from southwest to northeast late this afternoon into the
overnight with rainfall totals in the 0.10" to 0.8" range.

In addition to wet weather, very tight pressure gradients on the
backside of the surface low will lead to quite gusty conditions
this afternoon into Tuesday. Modeled soundings (HRRR/NAM/RAP/GFS)
suggest gusts around 35 to 50 knots at the top of the mixed layer
at most areas, and even close to 60 knots around the Buffalo Ridge
area this evening. Given that, northwest sustained winds of 25 to
35 mph are expected with gusts from 45 to 60 mph at times. Higher
gusts possible in southwest Minnesota. A High Wind Warning is in
effect for portions of southwest Minnesota this evening through
early Tuesday. The rest of the area is under a Wind Advisory which
is in effect from this afternoon through Tuesday afternoon.

In terms of temperatures, daytime temperatures will be a few degrees
below average with highs from the upper 40s to low 50s. With
northwest winds and strong cold air advection, overnight lows range
in the 30s.

.LONG TERM...(Tuesday through Sunday)
Issued at 346 AM CDT Mon Oct 21 2019

Drier air will quickly fill in behind the system Monday night into
early Tuesday as a weak surface high pressure builds in. However,
tight pressure gradients associated with the departing surface low
will still produce gusty conditions. Highest wind gusts are expected
east of the I-29 corridor with gusts as high as 40 mph through late
afternoon.

A weak shortwave slides south from the Canadian border/Northern
Rockies on Tuesday, approaching the region late Tuesday night into
Wednesday. The system will bring a quick shot of light rain
across the forecast area. Rain could be mixing with or changing to
light snow/flurries early Wednesday in areas north of I-90. Not
much forcing or moisture to work with, therefore minimal
accumulation is expected.

A surface ridge builds across the area after Thursday, bringing a
quiet/dry period into the weekend. Cold northwest winds will keep the
area cooler on Thursday with highs mainly in the 40s. Slightly warmer
temperatures are expected for Friday and Saturday with highs in the
50s and 60s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 621 AM CDT Mon Oct 21 2019

A large storm system will pivot across the area today. MVFR to IFR
stratus continues to form under the upper low. Scattered showers
will form by mid-morning, with stratiform rain overspread the area
this afternoon and evening. Winds will turn quite gusty by the
afternoon, with high winds greater than 40 to 50 mph likely this
evening and into the early overnight hours.

Stratus will hold on into the overnight hours, before conditions
improve late.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 4 PM this afternoon to 4 PM CDT Tuesday for
     SDZ065>071.

     Wind Advisory from 1 PM this afternoon to 1 AM CDT Tuesday for
     SDZ050-052-057-058-063-064.

     High Wind Warning from 4 PM this afternoon to 4 AM CDT Tuesday
     for SDZ040.

     Wind Advisory from 3 PM this afternoon to 4 PM CDT Tuesday for
     SDZ038>040-053>056-059>062.

MN...High Wind Warning from 4 PM this afternoon to 4 AM CDT Tuesday
     for MNZ071-072-080-081-097.

     Wind Advisory from 3 PM this afternoon to 4 PM CDT Tuesday for
     MNZ071-072-080-081-089-090-097-098.

IA...Wind Advisory from 4 PM this afternoon to 4 PM CDT Tuesday for
     IAZ001>003-012>014-020>022-031-032.

NE...Wind Advisory from 4 PM this afternoon to 4 PM CDT Tuesday for
     NEZ013-014.

&&

SHORT TERM...05
LONG TERM...05
AVIATION...Dux

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
414 AM CDT Mon Oct 21 2019

IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097-
098-NEZ013-014-SDZ038>040-050-052>071-220915-
Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Lincoln-Murray-Cottonwood-Nobles-Jackson-
Pipestone-Rock-Dixon-Dakota-Beadle-Kingsbury-Brookings-Gregory-
Jerauld-Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-
McCook-Minnehaha-Charles Mix-Douglas-Hutchinson-Turner-Bon Homme-
Yankton-Union-
414 AM CDT Mon Oct 21 2019

This Hazardous Weather Outlook is for portions of northwest Iowa,
west central Iowa, southwest Minnesota, northeast Nebraska,
central South Dakota, east central South Dakota, south central
South Dakota, and southeast South Dakota.

.DAY ONE...Today and Tonight

Scattered showers and a few rumbles of thunder are expected
through this evening. Severe weather is not expected.

Strong northwest winds gusting from 45 to 55 mph are expected at
times this afternoon into Tuesday. Highest gusts up to 60 mph
possible in southwest Minnesota.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Windy conditions continue on Tuesday with gusts up to 40 mph
possible at times.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.