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 Kansas City, 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 Kansas City (EAX) · issued Friday, September 11 at 2:16 AM CDT.
Messages
Areas of dense fog this morning will dissipate within a few hours of sunrise. Dens fog is most likely from parts of west central MO into central and northeastern MO.
There is a Marginal Risk for severe storms Saturday late afternoon into the overnight hours. Strong winds and hail are the primary threats with this activity.
There is potentially an active pattern setting up for next week, with multiple chances for showers and storms leading to potential for heavy rainfall. There is considerable uncertainty in the placement dependent on how strong and upper ridge is to our southeast.
Discussion
A surface high, centered over the Great Lakes, combined with residual moisture from yesterday's rain, is leading to widespread dense fog east of the KC area into central/northeastern MO, as of 07Z. This may eventually spread westward into parts of west central MO and east central KS by sunrise, given the weak pressure gradient and calm winds. A Dense Fog Advisory has been issued for areas east of Kansas City. Will monitor trends through the early morning hours. If fog does build westward, a westward expansion of the Dense Fog Advisory may be needed. Fog will dissipate within a few hours of sunrise.
Focus then shifts to the potential for strong to severe storms Saturday late afternoon into the overnight. Models show a shortwave trough moving across Central Plains into the Midwest. This helps push a front southward into the area which may lead to the development of storms during the afternoon hours. This is uncertain as while there is forecast to be ample storm energy, forecast soundings show capping in place as the front passes through. If storms are unable to develop during the day, the focus will shift to the evening/overnight hours, where forcing associated with the nose of the low-level jet will be key. Even with this, there is considerable uncertainty as the placement of the nose of the low- level jet and it varies by several hundred miles in the available guidance. In the deterministic guidance, the the regional model moves the low- level jet over the forecast area. The the American global model and the the European model are much further west, in central to western KS. This is beyond the time from the HREF and the LREF splits the difference with the low- level jet across central KS. With how far east the the regional model forecasts the low-level jet, it is naturally the most robust solution for the forecast area, tracking storms through the forecast area through the overnight hours. Conversely, the the American global model and the the European model are further west, with the later showing little in the way of expected rainfall.
For next week, the pattern becomes favorable for near daily/nightly precipitation chances across the Plains and Midwest. Our forecast area is on the northern periphery of the upper ridging centered over the Southeastern US. This effectively limits the southeastward extent of precipitation chances. Stronger ridging shifts the best chances northwestward. Weaker ridging allows for more of the forecast area to see higher precipitation chances. The ridging to the southeast will also help transport anomalously high moisture northward into the region. And with the area being persistently in the right rear quadrant of the upper- level jet, there is a good signal for heavy rainfall in the region, despite the uncertainty in its placement. As it currently stands, the northern portions of the forecast have best chance of seeing multiple rounds of storms with potential for cumulatively heavy rainfall next week. Our current forecast shows two to perhaps five inches of rain in far northern Missouri next week. For the 48 hour period ending at 7 am Thursday there is a 40-50% chance for at least 3 inches of rain.
This is the plain-text edition, decoded without AI so it loads anywhere. Read the whole Kansas City discussion at /o/EAX/, see what changed since the last one, or open The National Desk for where the weather is today.