Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 131104

Area Forecast Discussion
National Weather Service Sioux Falls SD
504 AM CST Mon Feb 13 2017

.SHORT TERM...(Today and Tonight)
Issued at 257 AM CST Mon Feb 13 2017

A surface trough will slide across the region today, with
southwesterly winds early in the day transitioning to
west/northwesterly by afternoon with the passage of the trough. Will
see winds pick up in the mid afternoon as the gradient tightens up a
bit and mixed layer winds increase, then taper down through the late
afternoon as the gradient relaxes. It will be another very mild day
for this time of year, with highs in the mid 40s through the western
and central Highway 14 corridor, to lower 50s along the Missouri
River Valley.

Northwesterly winds of around 10 kts will persist tonight, keeping
temperatures up a bit in spite of cold air advection, and looking at
lows in the mid and upper 20s.

.LONG TERM...(Tuesday through Sunday)
Issued at 257 AM CST Mon Feb 13 2017

Pleasantly warm weather and continued dry conditions are expected in
the mid and long range. The main focus has been on temperatures, and
specifically adjusting warmer than the blend.

Large upper level ridge over the Intermountain West today will
gradually expand eastward into the Plains through Thursday. For
Tuesday, flow will remain northerly, with breezy northwest surface
winds tapping into cooler air and allowing the coolest day of the
upcoming week. Still, with mostly sunny to partly cloudy skies, very
little snowpack, and an altogether not very cool airmass in
place, highs will still be above normal. Highs should manage the
upper 30s to mid 40s.

Return flow arrives on Wednesday, marking the beginning of the
upcoming warming trend. By Thursday, westerly winds and strong
warming aloft will further improve highs into the 50s to near 60.
Friday will be the warmest day of the period as 925 mb temperatures
surge to 8 to 13C. As previously mentioned, the SuperBlend continues
to be much too cold mid to late week, so have further nudged towards
the warmest guidance Wed through Fri, using the ECMWF. This should
give us highs in the upper 50s to mid 60s. Lows were also warmed

Upper ridge flattens and heads east Friday Night, while a deep
trough digs into southern California and Arizona. With a
southwesterly flow, clouds will be on the increase Saturday, which
should limit some of our warming potential. By Sunday, the forecast
becomes more uncertain regarding the track and timing of the
California trough. Both the GFS and ECWMF hint at rain chances
moving into the Plains on Sunday night into Monday, but with
temperatures still quite warm for the season, rain would be the main


.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 503 AM CST Mon Feb 13 2017

VFR conditions expected through the TAF period.




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