291 FXUS63 KFSD 202052 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 252 PM CST Wed Dec 20 2017 .SHORT TERM...(This evening through Thursday) Issued at 251 PM CST Wed Dec 20 2017 Models have bounced back a touch, but still indicating less than 2 inches for pretty much all locations. Forcing pretty much the same as the past couple of days and due to the unfavorable temperature profile and a general lack of moisture not expecting any measurable precipitation before about 9z tonight. Soundings still indicate a brief window over northwest IA late tonight and early Thursday morning where a little light freezing drizzle will be possible but at this time not expecting any major problems. A very small chance that some patchy very light freezing drizzle could occur as far north as Interstate 90 but not a good enough chance to mention. Closer to 12z around Chamberlain and Huron temperatures will begin to become cold enough to support precipitation and at this time it looks to be all snow. With the main component of the low and mid level frontal forcing cold air advection expect the band to be on the lighter side. There is a hint of a little instability above the mid level front so there could be a quick uptick in snow development from about 13z through 17z, but still do not think that this will cause any localized heavier snow. Not out of the question for someone to get closer to 3 inches, but pretty unlikely. This forcing slides south through the day and should slip into northwest IA by late afternoon. Did bump up snow amounts a touch, aiming for something close to an inch in southeast SD and southwest MN. Amounts should be less over northwest IA as forcing is weakening. There is a trailing mid level band of cold air advection collocated with some decent dendritic temperatures, so will linger the chance for light snow a little longer in case this band produces something, but will be pretty light. Temperatures will drop some this evening but remain steady through much of the night with stronger winds and clouds in place. MVFR stratus will continue to advect northward through the night from central Nebraska. Temperatures will be at about the warmest around sunrise, then steady or falling through the day. The exception could be central SD where some sunshine will be possible in the afternoon. .LONG TERM...(Thursday night through Wednesday) Issued at 251 PM CST Wed Dec 20 2017 Upper level energy remains somewhat zonal Friday through Saturday night before turning more northerly. This will keep less cold air in place for the weekend. Highs should be in the upper teens to mid 20s with lows about 5 to 15 above. Will not really mess much with what is given Monday through Wednesday. Models have been all over the place on how to handle the low level cold air. Some colder air lingering out there so there is good potential for a couple of pretty cold days, just not easy to say which days. The latest ECMWF would hint that Tuesday could be the coldest but not that cold Monday or Wednesday. Also suspect that we will have a few periods of light snow next week with some fairly favorable dendritic temperatures in the vicinity so that any wave producing some convergence will have a good chance to produce snowfall. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1140 AM CST Wed Dec 20 2017 MVFR ceilings streaming north through central Nebraska to just south of KYKN at 1740z. Expect this northward transport to slow a bit through the warmer part of the day, but then lift north and east after sunset. Widespread MVFR ceilings after about 5z Thursday, maybe some IFR conditions in northwest IA. Patchy light freezing drizzle will be possible in northwest IA early Thursday morning but confidence not real high. A band of snowfall will develop in central SD and spread south and east through the day. Lighter accumulations less than 2 inches are anticipated. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ SHORT TERM...08 LONG TERM...08 AVIATION...08