797 FXUS63 KFSD 310904 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 304 AM CST Thu Jan 31 2019 .SHORT TERM...(Today and Tonight) Issued at 304 AM CST Thu Jan 31 2019 As the cold air retreats care of an incoming upper level jet some light snow will be possible this morning into the early afternoon. Winds turn to the west and southwest in the low to mid levels as this jet dives south which will bring a broad area of warm air advection. With a favorable thermal profile supporting a fairly deep dendritic layer, any saturation that occurs will see a good chance to support snow growth and likely some snowfall at the surface. The best chances appear to be across southwest MN from mid morning into the early afternoon. Amounts will be limited due to the very cold air mass and marginal moisture but a half an inch to an inch will be possible with high SLR and a few hundredths liquid possible. Wind chill headlines will come to an end this morning with the coldest readings hanging in the longest across southwest MN. While temperatures will still be well below normal today after the past couple of days it will not fell too bad. Highs should reach near 10 above in southwest MN and the mid 20s along the Missouri River. Southerly flow will continue into tonight which will bring less cold low temperatures. With an increasing inversion some morning fog not out of the question but not likely to include in the forecast as confidence not real high at this time. The better chance would likely be between I-90 and the Missouri River where the inversion appears to increase the most. .LONG TERM...(Friday through Wednesday) Issued at 304 AM CST Thu Jan 31 2019 The upcoming mild pattern not a complete slam dunk as a strong inversion and some melting may allow some low level stratus and fog to develop at night and it could be a challenge to get rid of if it develops as mixing is not great and the current sun angle is still pretty low. Regardless, conditions will get a lot warmer than the past couple of days. Friday will still be struggling with snow cover and the retreating cold air mass. High should range from near 30 in southwest MN to 40 to 45 along the Missouri River Valley. Southerly flow will gradually increase Friday night into Sunday as the next system of interest moves onto the Plains. This should keep lows in the teens to upper 20s Saturday morning with highs Saturday climbing well into the 40s along the Missouri River. Along Interstate 90 temperatures may get stuck just a bit, possibly fighting with a little stratus and fog as well as the low level warm front potentially hanging up near Interstate 90. Expect highs from about 35 to 40 there and in the mid 30s along highway 14. Saturday night into Sunday low pressure should deepen across Wyoming and Colorado then spread east onto the Plains Sunday night into Monday. This increasing southerly flow will bring very mild lows Sunday morning ranging from near 20 in the mid James Valley to the upper 30s in northwest IA. Barring any stratus problems most locations will climb into the 40s Sunday with lower 50s not out of the question in parts of northwest IA. An interesting system still fairly consistently advertised in the models for Sunday night into Monday. A warm surge of air ahead of the system will bring a better chance for rain and snow as well as a threat for mixed precipitation. At this time the better threat for some warm and moist air to wrap northwest over the cold sector in the low levels will be near the MN and SD border north of Interstate 90. Obviously too far out to nail down any details but this appears to be the area with the better chance for a sustained period of warmer air aloft. To the south the transition should be pretty quick with maybe an hour of mixed precipitation but more than likely a rain to snow transition. For now aiming for the potential for about 1 to 3 inches of snow with a low confidence tenth of an inch of ice possible in the aforementioned area. Behind this system winds will increase quite a bit with northwest winds likely 20 to 40 mph. Conditions continue to look very cold Tuesday and Wednesday although not as cold as our latest cold snap we are recovering from this morning. Regardless, a good chance for wind chill values of 15 below to 30 below most locations both days. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1039 PM CST Wed Jan 30 2019 Low level stratus slowly expanding from the south late this evening, along with an increasing mid-level deck from the west. We'll gradually see ceilings lower this morning, which could lead to light snows along and east of I-29 by daybreak. The greatest snow risk will be found over the Buffalo ridge where a subtle shortwave will track along the baroclinic zone Thursday morning. Generally for aviation purposes, MVFR ceilings will be possible at all three terminals (Greatest risk at FSD), with only minor visibility restrictions. Improvement across the region should arrive by the afternoon. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...Wind Chill Advisory until 9 AM CST this morning for SDZ038-039- 050-052>071. Wind Chill Warning until 9 AM CST this morning for SDZ040. MN...Wind Chill Advisory until 9 AM CST this morning for MNZ089-098. Wind Chill Warning until 9 AM CST this morning for MNZ071-072- 080-081-090-097. IA...Wind Chill Advisory until 9 AM CST this morning for IAZ001>003- 012>014-020>022-031-032. NE...Wind Chill Advisory until 9 AM CST this morning for NEZ013-014. && $$ SHORT TERM...08 LONG TERM...08 AVIATION...Dux