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Area forecast discussion 
National Weather Service Sioux Falls South Dakota
554 PM CST Friday Nov 21 2014

Short term...(this evening through saturday)
issued at 400 PM CST Friday Nov 21 2014

Difficult low confidence forecast in the near term. Temperatures
have finally risen above freezing in most locations across the area.
This has promoted at least a little bit of snow melt. Area of
stratus that has been contained across Missouri and Kansas is now
creeping northward...and could impact portions of northwest Iowa
mainly east of the taf sites. On the back edge of the stratus...
hrrr...rap and sref suggest fog will develop after 06z. Tried to
keep mention of fog south of the Buffalo Ridge with strong winds
lingering in elevated locations. Kept lows mild north of the Buffalo
Ridge with downslope effect. Across the rest of the area...sided
fairly close to consensus.

Strong warming aloft is expected throughout the day on
Saturday...the question remains though as to how much of that
warming will surface. 925 hpa temperatures warm throughout the
day...starting near 3 to 5 c and warming to 5 to 7c by 00z Sunday.
Fog and/or stratus may linger through the morning hours...limiting
the potential to warm. Where there is a void of low clouds...should
see some nice warming with southwest flow across the area. Still
will be far from full mixout...but looks to be a relatively mild day
with temperatures above normal. Expect snow pack to continue to

Long term...(saturday night through friday)
issued at 400 PM CST Friday Nov 21 2014

Clouds build back into the area Saturday evening and night ahead of
the next storm system expected to impact the region Sunday through
Monday evening. Split flow will keep the area largely dry into
Sunday afternoon as the southern stream lifts a trough northward
from the Southern Plains into the middle Mississippi Valley on Sunday
while a trough digs into the northern High Plains along the northern
stream. With the forecast area stationed between these two
areas...drier conditions will prevail under some middle to high clouds.
A little light rain possibly mixed with some north in the northeast
may creep into our far eastern border during the day. It looks like
the best support for any wet weather will remain east of of the
forecast area. With somewhat breezy southwest winds and warmer air
aloft Saturday night...temperatures will stay mild overnight with
lows in the 30s. Sunday will remain mild as winds turn northwesterly
and become windy by afternoon. Temperatures warm into the middle 30s to
middle 40s before the cold air begins leaking back into the region
Sunday night into Monday.

With the northern stream wave sliding across the northern plains
Sunday evening through Monday...some light snow will spread east
across the area. Moisture does not look too impressive with this
wave...however some decent frontogenesis and modest qg forcing
sliding through the area will allow for some isolated to scattered
light to fall. Most areas will see less than half inch...but could
be a little higher in parts of southwest Minnesota. With blustery
winds...any snow that does fall will blow around...but any existing
snow pack should have enough of a crust to not cause any blowing
snow issues.

Models showing better agreement heading into the middle of next
week. Left a low chance for light snow mainly across our northern
half on Tuesday night as another front drops through the region. Dry
and cold weather persists Wednesday and Thursday...with highs
cooling further into the middle teens to middle 20s. Sharp ridging over
the intermountain west eases into the plains and flattens out...but
temperatures look much milder on Friday.


Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 546 PM CST Friday Nov 21 2014

Forecast remains a challenge tonight into tomorrow. Watching large
area of low stratus continue to push north towards the region. Am
pretty confident ksux will go MVFR by around 04z and eventually
IFR later tonight. Could even see ceilings drop into the LIFR
range...with dense fog possible as well. Also pretty confident
khon stays VFR. Less certain about kfsd...which will likely be
near the west edge of any stratus and fog. Based on the latest rap
and hrrr decided to bring IFR ceilings into kfsd later
tonight...although again confidence is low. What is also uncertain
is how quickly the stratus and fog exits tomorrow. Stayed on the
optimistic side for now given low confidence...but would not be
surprised if low ceilings and visible stick around longer than currently winds will stay out of the south southeast through
the day.

So in the least think northwest Iowa will see low
stratus and potentially dense fog tonight into early tomorrow.
This could extend as far west as the Interstate 29 corridor. For
now have improvements by middle morning...but the possibility is
definitely there that these conditions linger into late morning or
even early afternoon.


Fsd watches/warnings/advisories...
South Dakota...none.


Short term...
long term...

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