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Area forecast discussion 
National Weather Service Sioux Falls South Dakota
617 PM CDT Friday Oct 24 2014

Short term...(this evening through saturday)
issued at 300 PM CDT Friday Oct 24 2014

Settling in for a quiet 24 hours across the area. Very warm readings
this afternoon in the 70s for most...westerly flow ahead of cold
front arcing from northern to western South Dakota. Boundary will
push southward through the night...with high pressure filtering
southward. Winds should push up briefly behind the boundary shifting
to the northwest...but overall stabilization during the evening will
keep winds from attaining stronger mixed values occurring behind the
boundary early this afternoon. Much drier airmass will mean a break
from the fog threat...even as wind diminishes across the western
half of the County Warning Area later tonight. Did...however...take temperatures down
several degrees...especially through valley areas in the western
half. SW Minnesota into parts of northwest Iowa are likely to hold on to a bit more
light northerly wind through the night.

Saturday will bring a splendid day as tendency for high clouds will
be somewhat less...and winds largely light...after some potential
mixing of northerly component across the east during the morning...
and increase southeast winds through the far west by afternoon. A
solid 10 to 15 degrees above normal...with upper 60s to lower 70s
comfortably attained with usual large diurnal ranges of late.

Long term...(saturday night through friday)
issued at 300 PM CDT Friday Oct 24 2014

The forecast for Sunday is rather a tricky one. Upper level ridging
shifts further east into the upper Mississippi Valley with southerly
low level winds becoming breezy by afternoon. The main concern is
the possibility of some low stratus spreading into the
region...which the models continue to hint at. If the stratus does
materialize and last into the afternoon hours...temperatures will
remain much cooler than guidance suggests. Based on moisture
trends...think that our western half should break out of any cloud
cover early in the day and warm quickly into the middle to upper 70s.
The eastern half however is much less certain with a great potential
for stratus to linger if it manages to develop. With some
uncertainty in this regard...went somewhat middle of the Road on
temperatures with highs in the upper 60s. But any changes in
expected cloud coverage could result in much warmer or cooler
readings. Dry weather should prevail however...given very dry middle

Model guidance showing better agreement than 24 hours ago on the
strength and track of a broad upper level trough impacting the
northern plains mainly Monday and Monday night. The Gem is more
similar to the former GFS in closing off the low and slowing
it...but all models are favoring a more northern and faster track
through the northern plains. Isolated showers may form in the
western forecast area Monday morning as the moisture begins to
increase...but dry middle levels may initially prevent much of any
precipitation from getting going. By afternoon and evening...chances
increase across the area...but moisture remains somewhat marginal
and any showers the develop will be rather light. The wave should
exit into the boundary waters area Monday night and any lingering
showers in our east should end by Tuesday morning. With clouds..rain
showers and cooler air aloft arriving...temperatures will be cooler
as well. Highs are expected in 50s on Tuesday with a very brisk
northwest wind.

Models begin to really show some differences late in the period on
Wednesday and beyond. Overall cool northwest flow will keep
temperatures near seasonal readings...but dry conditions will
generally prevail. The European model (ecmwf) and GFS hint at a weak wave sliding
through the area on Wednesday night...but given the dry middle and low
levels...will leave out any precipitation mention for now until
confidence is greater.


Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 616 PM CDT Friday Oct 24 2014
VFR conditions expected through the period. Light westerly winds
will transition to a light easterly flow towards 00z Sunday.


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


Short term...Chapman
long term...

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