Area Forecast Discussion
Issued by NWS Sioux Falls, SD
Issued by NWS Sioux Falls, SD
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765 FXUS63 KFSD 232333 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 533 PM CST Sat Nov 23 2024 .KEY MESSAGES... - Mild temperatures and mostly dry conditions will dominate this weekend. A slight uptick in potential for snow north of I-90 tomorrow evening, but still a half an inch or less accumulation expected. - Below to well below normal temperatures move in Monday and persist through the Thanksgiving holiday week. Aside from a brief reprieve in southern areas Tuesday-Wednesday, confidence is high (>80%) that temperatures will remain below freezing, with moderate (40-60%) chances that highs will not reach 20F by the end of the week. - Light precipitation chances remain low, with chances for light snow/flurries peaking at 10-20% Wednesday night. Those with more distant travel plans will want to monitor forecast trends, though, with higher precipitation chances south of I-80 and in northern Minnesota during the holiday travel period. && .DISCUSSION... Issued at 237 PM CST Sat Nov 23 2024 An upper level jet streak will spread from west to east tonight into Sunday with low pressure developing to the north. This will spread a broad area of mid level warm advection across the area tonight, but for now this layer looks very dry so precipitation should not develop. This trend continues into the day Sunday, then by late Sunday afternoon and evening a mid level wave moves through as low and mid level cold air advection increases. This will be the slightly better chance for light rain or light snow, but still a struggle to saturate the low and mid levels. Not to mention the dendritic growth zone is sitting up around 14-16kft. So, overall no real changes to the forecast with mainly sprinkles/flurries expected. Latest GEFS through the 75th percentile sitting at zero precipitation with the 90th kicking out a few hundredths. Will need to keep an eye on the EC and its` ensemble members as the 50th percentile is about 0.05" liquid north of I-90 with the 90th around 0.15", which would equate to about 0.5" to 1.5" of snow. While tomorrow will be on the mild side again, once this wave passes colder air will spill into the area with lows in the teens to lower 20s Monday morning and highs mainly in the mid 20s to lower 30s. Not only will it be colder but winds will remain fairly windy with gusts around 35 mph likely, especially near and east of I-29. These colder temperatures and stronger winds will combine to produce wind chills in the single digits above and below zero. While there will be a few chances for light precipitation Tuesday through Friday the main story will be continued below normal temperatures with another shot of colder air expected Thursday into Friday, dropping highs back into the teens to lower 20s Friday. One thing to watch will be Thanksgiving afternoon through Friday morning. With the incoming colder air the dendritic growth zone will lower and deepen and could lead to a little patchy light snow. Nothing overly predictable at this range but if we can squeeze out a little moisture in this layer or generate some shallow convection in the marginally strong cold air advection we could get some light snow amounts. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 533 PM CST Sat Nov 23 2024 VFR conditions begin the TAF period. High level cirrus blankets the area early this evening along with light easterly winds. Winds will go light and variable tonight which could allow for patchy fog to develop. However,confidence is not high enough to include in a TAF at this time. At the same time, MVFR/IFR stratus will expand westwards during the overnight hours. Should see the stratus cover the majority of the area by tomorrow afternoon. Precipitation is possible by KHON towards the end of the TAF period. Given lower confidence in timing, have omitted from KHON`s TAF but will monitor trends. Otherwise, winds will turn out of the north/northwest to end the TAF period. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...08 AVIATION...Meyers