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Area forecast discussion 
National Weather Service Sioux Falls South Dakota
625 PM CDT Wednesday Apr 16 2014

Short term...(this evening through thursday)
issued at 418 PM CDT Wednesday Apr 16 2014

700-750 mb frontogenetic band quickly shifting east through the
forecast area through the early evening hours. Have minor
accumulations across southwest Minnesota with heaviest accumulations
along the Highway 14 corridor where amounts will generally range
from 2-3 inches. Large batch of stratus extending back to the
northwest...and have increased cloud cover through the overnight.
This should reduce radiative cooling...along with the gradient wind
that will remain somewhat brisk through the overnight. Have sided
close to cons lows...but lowered a degree or two in the north along
the Highway 14 corridor.

Have sided with the idea that the stratus would gradually shift east
through the day tomorrow...but there is a chance that if the
northeast and easterly flow that develops with the weak high
pressure system that stratus could linger longer than currently
forecast. Have sided with slightly less than 850 hpa mixout...with
weak winds and potential cloud cover remaining.

Long term...(thursday night through wednesday)
issued at 418 PM CDT Wednesday Apr 16 2014

Models coming into better agreement Thursday night into Friday. The
European model (ecmwf) and Gem solution from yesterday featuring the weaker
wave...quicker building of the ridge...and thus warmer coming true. Does appear like there may be just
enough lift and middle level moisture on Thursday night into Friday
morning to get a few showers...but not expecting anything
significant. Slight chance probability of precipitation seem good enough for now. Thinking
anything will more than likely be in the form of rain although can
not rule out a few flakes of snow or a bit of freezing rain with
temperatures in the low 30s. But not expecting any real issues at
this point. Skies will be mostly cloudy to start Friday...but expect
enough clearing to allow for full mixing into our warm 925 mb
temperatures. Thus went ahead and made a significant change to high
temperatures for Friday...raising them into the middle 50s across
southwest Minnesota and 60s to near 70 along the Missouri River.
Would not be surprised if we even end up a few degrees warmer than
the current forecast.

The weekend into early next week looks warm with above normal
temperatures. Rain chances are a bit complicated with our County Warning Area split
from the best forcing...with the northern stream wave staying
north...and the southern stream to the south. Instability also
remains pretty minimal over our area...with the higher values
staying south. Still kept some low chance probability of precipitation in the grids for
Saturday. As we may see enough moisture advected north along and
ahead of the front to get a few showers...maybe a thunderstorm. Not
expecting anything significant though. Uncertainty higher Saturday
night into Sunday. European model (ecmwf) stalls the frontal boundary over northwest
Iowa...with some interaction from the southern stream wave. This
results in showers over the eastern half of the area later Saturday
night into Sunday morning. Only the European model (ecmwf) is really showing will go just chance probability of precipitation at this confidence on
which solution verifies is low. Expecting temperatures in the 60s and
70s on both Saturday and Sunday. Trended highs up both days towards
consensus values. Exact highs will depend on cloud and shower
coverage and placement each as confidence increases on this
future shifts can adjust highs up or down as needed.

Upper ridging builds in Monday into Tuesday ahead of trough pushing
into the western portion of the country. Thus the warm conditions
look to continue with highs in the 60s and 70s. Shower and
thunderstorm threat increases Tuesday into Tuesday night as the warm
front lifts north. Current indications are that we get into the warm
sector Wednesday...with the potential of getting very warm. However
models having a tough time pinning down the evolution of the trough
and exact timing of the cold front. For now the most we can say is
that there is the potential for a day or two of very warm
temperatures...and that shower and thunderstorm chances generally
increase Tuesday through the rest of the week...although exactly
which days have the best rain chances remain uncertain.


Aviation...(for the 00z tafs through 00z Thursday evening)
issued at 623 PM CDT Wednesday Apr 16 2014

Of the biggest concern in the near term is southwest Minnesota...where
LIFR conditions will prevail through about 02z/17 as a band of
rain and snow moves across that area. Otherwise the prevailing
category in the Sioux Falls forecast area for much of the night
should be in the MVFR category as stratus moves down from the
north and northwest. The NAM and GFS project this stratus to exit
from north to south late tonight and early Thursday...leaving VFR
conditions for much of the day on Thursday along with light winds.


Fsd watches/warnings/advisories...
South Dakota...none.
Minnesota...Winter Weather Advisory until 9 PM CDT this evening for mnz071-



Short term...
long term...chenard