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 Friday, September 11 at 6:42 AM CDT.
Messages
Breezy to strong southerly winds are expected today with gusts between 30-40 mph expected for most areas. Slightly stronger winds will be possible across the Buffalo Ridge in southwestern MN.
A conditional chance for stronger storms is expected this afternoon and evening mainly east of I-29. While all hazards remain possible, 2 inch hail and damaging winds up to 70 mph will be the primary threats.
A pattern shift will lead to cooler conditions over the weekend with highs mainly in upper 60s to 70s. Periodic rain chances will continue into the new week.
Update
Not many significant changes on the weather front with the main focus being on the breezy to strong winds today and the potential for severe weather this afternoon/evening. Starting with the winds, southerly surface winds should increase just after daybreak as the surface pressure gradient tightens ahead of an approaching cold front. This will lead to wind gusts recurringly in the 30-40 mph range for most areas throughout the day. Still thinking that a pocket of stronger winds (40-50 mph) will develop along the eastern side of Coteau Des Prairies as mixing deepens and the 850mb to 925mb LLJ strengthens. With this being further agreed upon by short-range guidance, decided to pull the trigger on a Wind Advisory from 7 am to 7 pm on the Buffalo Ridge in southwestern MN. Should see surface winds gradually weaken after the front progresses through the area this evening.
Otherwise, the focus continues to be on the severe weather chances for the second half of the day. Still thinking our chances for anything stronger will be conditionally dependent on if we can break through the weakening cap. With daily heating, the best chances will likely occur be between 5pm to 10pm mainly east of I-29. IF this occurs, isolated to scattered updrafts could quickly become severe with access to between 1500-2000 J/kg of storm energy and 30-40 knots of bulk shear. While all hazards will be possible, steep mid-level lapse rates and inverted "V" sounding profiles will favor up to 2 inch hail and damaging wind gusts up to 70 mph. Though confidence is low, if a discrete supercell can anchor to the surface front; an isolated tornado can't rule out. Lastly, should see most of this activity exit our area around midnight with the cold frontal passage.
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.