047 
FXUS63 KFSD 120436
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1036 PM CST Sat Feb 11 2017

.SHORT TERM...(This evening through Sunday)
Issued at 230 PM CST Sat Feb 11 2017

Surge of strong mid level frontogenesis is currently shifting slowly 
southeastward across the forecast area along a weak mid level short 
wave. The lowest layer of the atmosphere, generally below 850mb, 
still remains rather dry, with the driest air along the northern and 
southern fringes of our atmosphere. The strongest part of the 
frontogenesis remains along and just south of I 90, so it follows 
suit that this is where the strongest rain echoes currently are. 
However all rain is very light, little more than sprinkles in some 
locations. Stronger northern stream short wave then drops 
southeastward this evening and overnight with some notable PV. This 
will help to linger some light showers in the forecast area this 
evening, then a clearing trend will follow. But interestingly, both 
the NAM and GFS are showing about a two to three hour stripe of 
stratus moving rapidly southeastward along the PV surge which is 
coupled with subtle cold air advection. Therefore included a stripe 
of cloudiness moving rapidly southeastward late tonight, but overall 
the trend is for clearing. As the wind increases along and behind 
the PV surge to 20 to 30 mph, low temperatures will not drop off all 
that much, with a lot of 25 to 30 degrees.

Sunday will see plenty of sunshine. As has been the trend the past 
couple of days, warmed highs above superblend, generally trending 
closer to the raw ECMWF numbers which gives a lot of lower to mid 
40s. With a breezy or windy northwest wind, albeit going down in the 
afternoon, would not be shocked if highs end up a category warmer.

.LONG TERM...(Sunday night through Saturday)
Issued at 230 PM CST Sat Feb 11 2017

A very quiet weather pattern is expected from Sunday night 
through Saturday. In general, all models are in agreement on the 
evolution of the pattern with a long wave ridge moving from the 
Rockies into the western Great Lakes by the end of the week. The 
result is above normal temperatures through the week with the 
potential for near record highs by Friday. The only model 
differences are really with the degree of warming with the GFS and
NAM generally 2 to 4 C cooler at 925 mb than the Canadian and 
ECMWF. Given the GFS had a cold bias for yesterday's record 
warmth, have generally sided with the EC and Canadian for 
temperatures this forecast. Overall confidence is high that 
temperatures will remain above normal with temperatures 20-30 
degrees above normal possible toward the end of the week. No 
precipitation is expected through Saturday. 

On Monday, the passage of a dry cold front during the day will 
allow for 925 mb temps from 5 to 10 C to advect ahead of it and 
winds to become southwesterly. This favors a fairly well mixed 
atmosphere. Only an early frontal passage around Huron and 
Brookings will keep highs there in the lower to middle 40s. 
Otherwise, upper 40s to lower 50s are expected. Cooler, but still
above normal, temperatures are expected Tuesday and Wednesday as 
northwesterly flow becomes established. On Tuesday, winds will 
gust over 20 mph but high pressure will move over on Wednesday 
resulting in lighter winds. Highs both days will be in the upper 
30s to mid 40s. Southerly flow will increase beginning Wednesday 
afternoon and continuing into Friday. Temperatures will be in the 
mid 40s to mid 50s on Thursday and then mid 50s to mid 60s on 
Friday. And if the EC/Canadian are right, it could even be warmer 
with a few places in south central SD possibly reaching 70. While 
Saturday looks to be a little cooler, temperatures are still 
expected to be in the 50s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1032 PM CST Sat Feb 11 2017

Rain is clearing the area as midnight approaches. Biggest concern
overnight and into Sunday will be with potential for a quick burst
of gusty winds thanks to rather sharp pressure rises moving into
the area. Soundings suggest a fairly mixed boundary layer up to 2k
ft agl by 5am, with potential for downward momentum transfer up to
40 mph through daybreak. 

Strong gusts will subside early Sunday, but as mixing deepens
again, could see gusts approach 30 mph by the afternoon. 

&&

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

$$

SHORT TERM...MJ
LONG TERM...Schumacher
AVIATION...Dux