Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kfsd 211702 
afdfsd

Area forecast discussion
National Weather Service Sioux Falls South Dakota
1202 PM CDT Mon Oct 21 2019

Update...
issued at 1159 am CDT Mon Oct 21 2019

The latest forecast models continue to indicate strong northwest winds
will occur this afternoon, evening, and overnight. Widespread
rain showers will also help Transfer momentum down from the top of
the mixed layer. Wind speeds of 55 to 70 mph will be common a few
thousand feet above ground level, which should translate into 50
to 60 mph surface wind gusts for the portion of the area covered
by the High Wind Warning. This warning area was expanded to
include the areas where 55 to 60 mph gusts are most likely.

&&

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 South Dakota/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 18z tafs through 18z Tuesday afternoon)
issued at 1159 am CDT Mon Oct 21 2019

Very strong surface winds gusts of 50 to 60 mph are likely this
afternoon, evening, and overnight. Rain showers will accompany
these potentially damaging wind gusts. Low level cloud decks
remain common through the next 24 hrs, but most precipitation
will end by midnight. By sunrise Tuesday, the strongest winds will
likely have eased somewhat, but Tuesday remains breezy with 45
mph wind gusts through the day.

&&

Fsd watches/warnings/advisories...
South Dakota...High Wind Warning from 4 PM this afternoon to 4 am CDT Tuesday
for sdz039-040-054>056-061-062-066-067-070-071.

Wind Advisory until 4 PM CDT Tuesday for sdz038-053-059-060-065-
068-069.

Wind Advisory until 4 PM CDT this afternoon for sdz039-040-
054>056-061-062-066-067-070-071.

Wind Advisory from 4 am to 4 PM CDT Tuesday for sdz039-040-
054>056-061-062-066-067-070-071.

Wind Advisory until 4 am CDT Tuesday for sdz050-052-057-058-063-
064.

Minnesota...High Wind Warning from 4 PM this afternoon to 4 am CDT Tuesday
for mnz071-072-080-081-089-090-097-098.

Wind Advisory until 4 PM CDT this afternoon for mnz071-072-080-
081-089-090-097-098.

Wind Advisory from 4 am to 4 PM CDT Tuesday for mnz071-072-080-
081-089-090-097-098.

Iowa...High Wind Warning from 4 PM this afternoon to 4 am CDT Tuesday
for iaz001>003-012>014-020>022-031-032.

Wind Advisory until 4 PM CDT this afternoon for iaz001>003-
012>014-020>022-031-032.

Wind Advisory from 4 am to 4 PM CDT Tuesday for iaz001>003-
012>014-020>022-031-032.

NE...High Wind Warning from 4 PM this afternoon to 4 am CDT Tuesday
for nez013-014.

Wind Advisory until 4 PM CDT this afternoon for nez013-014.

Wind Advisory from 4 am to 4 PM CDT Tuesday for nez013-014.

&&

$$

National Weather Service Glossary of Abbreviations