Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 291127
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
527 AM CST Tue Nov 29 2016

.SHORT TERM...(Today and Tonight)
Issued at 315 AM CST Tue Nov 29 2016

Ongoing stagnant storm system spinning north of the forecast area
near the lower Red River Valley will be primary focus through the
next 24 hours. Bands of lift and moisture will continue to rotate
around the system, spreading occasional light precipitation into
mainly our southeast South Dakota and southwest Minnesota counties
through tonight. Thermal profile aloft continues to support snow,
although very shallow near surface warm layer could result in some
brief periods of rain or rain/snow mix during the daylight hours
today. Transitions to rain or drizzle could also occur when pockets
of drier air aloft rotate through the region between the bands, and
we lose ice and resulting ability to produce snowflakes within the
column. Thus have introduced some patchy freezing drizzle/drizzle
into the forecast into this evening, however do not anticipate much
additional impact from brief periods of freezing drizzle early this
morning.

Widespread cloud cover and scattered precipitation will result in a
small diurnal temperature range, from overnight lows within a couple
degrees of 30, and daytime highs generally 35-40 degrees, though far
southern portions of the forecast area around Sioux City could sneak
a little above 40. Westerly winds will also remain brisk, and could
approach wind advisory levels in south central South Dakota. Appears
to be just shy of criteria, though so will hold off on headlines
for now.

.LONG TERM...(Wednesday through Monday)
Issued at 315 AM CST Tue Nov 29 2016

The cool upper low will be moving slowly east from MN into WI
Wednesday and Wednesday night. Light precipitation coverage
should gradually decrease. It looks like accumulations around an
inch are possible from 12Z Wednesday on, from east of Huron into
southwest MN. Continued weak low level frontogenesis and lift, up
to 850mb, will slowly shift east. Elevation will continue to be a
factor, as will modest diurnal warming. In any event, the best
snow accumulation potential appears to be in the morning
Wednesday.

There is some chance of a slight resurgence in light snow Wednesday
evening, as a last short wave moves over the area on the western
side of the retreating low. However, will go with guidance
decreasing chance POPs for Wednesday night, as this wave looks
quite weak.

Dry weather should be the rule Thursday through Monday, with two
possible exceptions. One would be a little light snow early Sunday,
around Interstate 29 and east, north of Sioux Falls. A weak
westerly wave not showing up very well on the GFS, but depicted on
the last couple runs of both the EC and Canadian, could bring that
minor event. The other exception would be a chance of rain and
snow east and south of Sioux Falls by late Monday. This would be a
post frontal band supported by a broad approaching trough. Current
indications are that the coldest air of the season so far will
arrive next week behind this system, and just beyond the current
forecast period. The new EC is slower on this system and would
delay its arrival by a day or so.

Temperatures which are modestly cool will warm to a little above
normal for the weekend into Monday, with highs during that time
frame in the 30s to lower 40s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 527 AM CST Tue Nov 29 2016

MVFR ceilings will be prevalent across the region through this TAF
period, with occasional dips into IFR range, mainly in the higher
elevations east of KHON and north of KFSD. Occasional snow showers
will also swing through the region, largely remaining north of a
KYKN-KSPW line. MVFR-IFR visibility will be common with the snow
showers. Could see occasional lowering to LIFR range, but timing
these is difficult and have limited visibility in KHON/KFSD TAFs
to 1SM or greater.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&

$$

SHORT TERM...JH
LONG TERM...
AVIATION...JH


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