Plaincast
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 Portland, 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.
A cool and unsettled weekend is ahead as an upper-level low moves across the Pacific Northwest. Widespread rain and showers will develop Saturday and continue into Sunday, with temperatures remaining below seasonal average. A much warmer and drier pattern then develops early next week as high pressure builds offshore.
Now through Thursday. Today will be a relatively quiet day between weather systems, but temperatures will remain cool compared to yesterday. Increasing clouds ahead of the next system will limit afternoon warming, with highs reaching the upper 60s to low 70s across the interior and low to mid 60s near the coast. Some interior valleys could also see patchy fog or low clouds this morning where skies remain clear, especially in areas with light winds and higher surface moisture.
The next system will become the main weather story this weekend. An upper-level low will deepen offshore tonight before moving across the region Saturday. Recent guidance continues to suggest that rain will reach the coast Saturday morning and spread inland through the afternoon. Rain and showers will continue Saturday night, followed by additional showers through most of Sunday. Confidence is high that most of the forecast area will see measurable precipitation, with most ensemble members supporting rain somewhere across the region.
Saturday through Sunday, total rainfall amounts should generally remain on the lighter side, with around 0.10-0.50 inch expected for most locations. The Cascades will likely receive more, with the southwest Washington and north Oregon Cascades currently favored for the highest totals around 0.50-1.00 inch (highest values in the southwest Washington Cascades). Showers will become more scattered Sunday as the system moves east, although the higher terrain will continue to have the best chance for stratiform rain.
There is also a slight chance for thunderstorms (15-25% chance) Saturday as the cold air associated with the upper-level low moves overhead. How much instability develops will depend partly on the timing of the system. If the coldest air arrives later in the day, after daytime heating has weakened, thunderstorm chances will be lower. An isolated thunderstorm is still possible, however. Cold-core funnel clouds could also develop near the upper low. These are generally short lived and often remain above the ground, but a funnel reaching the surface cannot be completely ruled out.
The weekend system will also bring another noticeable drop in temperatures. Highs Saturday and Sunday will generally be in the low to upper 60s across the interior. Conditions should gradually improve Sunday night as the low moves east and shower activity decreases.
A much warmer pattern is then expected to develop early next week as high pressure strengthens over the eastern Pacific. Some lingering troughing could keep Tuesday from becoming completely clear and warm, but the overall trend is toward drier weather and rising temperatures. Interior highs should climb into the mid to upper 70s by Tuesday.
This is the plain-text edition, decoded without AI so it loads anywhere. Read the whole Portland discussion at /o/PQR/, see what changed since the last one, or open The National Desk for where the weather is today.
Data from the National Weather Service. Translated by Claude. About · For developers & agents · Subscribe: RSS feed for this office · Source on GitHub