What the forecast actually says — NWS Area Forecast Discussions, decoded into plain English.
Plaincast decodes the National Weather Service's Area Forecast Discussion — the real forecast, written 3 to 4 times a day by the meteorologist on shift — into plain English. The discussion is where a forecaster explains their reasoning: which models disagree, what they are watching, and how confident they are. Below is the current edition for Sioux Falls, with its shorthand expanded. The full experience — an AI plain-English summary beside the annotated original — loads with JavaScript, and every one of the 68 forecast offices has its own edition.
Area Forecast Discussion · National Weather Service Sioux Falls (FSD) · issued Saturday, October 24 at 6:34 AM CDT.
Messages
BREEZY WITH FALLING TEMPERATURES TODAY: A push of stronger winds arrives in south-central South Dakota near/just after sunrise. Gusts with this will increase to 35-40 mph for a brief period.
COOLER WITH SCATTERED WEEKEND RAIN: A slow-moving front will bring increased clouds and occasional rain this weekend. Temperatures will be notably cooler (40s/50s) by Sunday.
SIGNIFICANT RAINFALL LIKELY MONDAY-TUESDAY: A large multi-day system will bring widespread rain to start the new work week. Confidence in amounts over 1" through Tuesday morning remain high.
ACTIVE WEATHER CONTINUES: A second fast moving system may bring rain chances back by Tuesday Night and Wednesday, with temperatures near seasonal normals.
Update
Scattered showers and very isolated thunderstorms are expected today as mid level moisture streams northward. This is in response to a strong north/south oriented jet that will increase through the day. Weak (300-500 J/kg storm energy) instability will bring the threat for a little lightning and very brief downpours. The better chances for this will be near and west of I-29. With the freezing level around 11 kft, even small hail is not expected. While most areas will only see lighter accumulations, some spotty locations could see 0.10" to 0.25".
While there will likely be a bit of a lull in showery activity from about mid afternoon into the early overnight hours, the next wave looks to move into central SD later tonight into Sunday. Low and mid level winds respond to this wave, increasing warm air advection and deepening moisture. Once again, the better chances appear to remain mostly west of I-29.
The area begins to lose saturation in the dgz on Sunday as this wave moves north through central SD. Saturation remains most persistent west of highway 81, with northwest IA seeing the largest struggle to saturate aloft. Some very weak elevated instability in northwest IA later Sunday afternoon may allow for a spotty shower or two.
Monday may end up cooler than forecast with low level cool air likely remaining locked in with rainfall occurring. Interesting to note that the Nam, while an outlier, would potentially bring a little mixed precipitation or snow to the Huron and Chamberlain areas Monday afternoon/evening. Most of the other data hangs on to slightly warmer temperatures, but not by a lot. Slightly warmer low level temperatures would also be supported by the exiting of the right entrance region of the northern jet and the increase of the southern jet during this time.
To put all of this into perspective, the latest Nam and RRFS total qpf through Tuesday morning places about 1-2.5" over south central into east central SD and while the EC ensemble, GEFS and Canadian ensemble are a bit more broad with their output, the location is very similar, if not a touch farther west. A fairly tight gradient from higher amounts to lower amounts will likely set up from about Vermillion to Windom. All in all this tracks fairly well with the mid level waves (700-500mb) over the next few days.
This is the plain-text edition, decoded without AI so it loads anywhere. Read the whole Sioux Falls discussion at /o/FSD/, see what changed since the last one, or open The National Desk for where the weather is today.