Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kfsd 220436 
afdfsd

Area forecast discussion
National Weather Service Sioux Falls South Dakota
1036 PM CST Thu Nov 21 2019

Short term...(this evening through friday)
issued at 250 PM CST Thu Nov 21 2019

Breezy north winds continue through the afternoon hours, advecting a
cool air mass into the region. Low overcast skies will slowly clear
as drier air mixes in. As a large surface low pressure moves further
east over the Great Lakes overnight, the pressure gradient weakens,
causing winds to become light and variable. This combined with
clearing skies will allow good radiational cooling causing early
morning temperatures to be on the lower side of model guidance;
therefore, have continued this trend in the official forecast.

Friday will be a quiet day weather-wise, with slowly moderating
temperatures near seasonal normals (upper 30s to around 40). No
precipitation is expected with light southwest winds and mostly
sunny skies.

Long term...(friday night through thursday)
issued at 250 PM CST Thu Nov 21 2019

The quiet weather trend continues for the weekend. Dry northwest
flow aloft due to a robust ridge over the western Continental U.S. Will keep
the air mass over the region fairly dry with partly cloudy skies.
Temperatures will warm by about 5 degrees each day due to the
warming air mass and light southwesterly winds. Sunday is forecast
to be the warmest day of the next week. Temperatures run well above
normals: mid to upper 50s are likely in south central South
Dakota.

A subtle northern stream shortwave will drag a weak surface cold
front through the area Sunday night into Monday. Light
precipitation is possible with this feature, but there is not much
moisture to work with, so not expecting much (if any)
accumulation. A deeper trough is then forecast to move through the
plains Tuesday, but this system has continued to track further to
the south, with models coming into better agreement. Tuesday and
Wednesday are very busy travel days leading up to Thanksgiving, so
those heading south to places such as Omaha & Kansas City will
want to keep a close on this system; however, locations as far
north as our area (including Sioux City and Sioux falls) are
forecast to remain mostly precipitation-free. Cloudy skies are
likely due to troughing and modest lift aloft, but no significant
sensible weather is expected at this time.

The large scale pattern becomes more amplified during the middle of
next week. A deep trough over the west could provide some modest
lift on Thanksgiving, but the more impactful conditions currently
look to remain outside of the tri-state area. That being said,
confidence on details is still fairly low 7 days out. Temperatures
are forecast to be near normals for the Holiday with mostly cloudy
skies.

&&

Aviation...(for the 06z tafs through 06z Friday night)
issued at 1036 PM CST Thu Nov 21 2019

Some MVFR ceilings still lingering around mml and spw but they
shoudl dissipate between 6-8z and shift east. Otherwise VFR
through the period.

&&

Fsd watches/warnings/advisories...
South Dakota...none.
Minnesota...none.
Iowa...none.
NE...none.
&&

National Weather Service Glossary of Abbreviations