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 Phoenix, 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 Phoenix (PSR) · issued Friday, September 11 at 3:25 AM MST.
Messages
Extreme Heat Warnings continue across portions of southeast California and southwest Arizona through early evening while temperatures gradually cool into the weekend.
Chances for scattered showers and isolated thunderstorms will continue to be focused mainly over the Eastern Arizona high terrain through the weekend before increasing in coverage and spreading into the lower deserts early next week.
Near to slightly above normal temperatures are expected for this weekend and likely through the first part of next week.
Short Term
Relatively quiet weather conditions will prevail today and likely through Saturday. The subtropical ridge has weakened enough to start a cooling trend today, but above normal temperatures will still easily persist today. Extreme Heat Warnings for portions of the western lower deserts continue through this evening with highs from 106-110 degrees with even higher heat indices. The lower heights and slight cooling aloft will help to bring daytime highs across the south-central Arizona lower deserts to 103-106 degrees, or 3-4 degrees above normal. Today will also bring limited convective potential with the subsidence inversion still inhibiting convection over the lower deserts and to a decent degree over the high terrain. The best potential (10-20%) chance of rain looks to be from late evening through the first part of the overnight hours from Phoenix and areas east of Phoenix.
Saturday looks quite similar to today with moisture levels remaining marginal enough to have a hard time overcoming the subsidence inversion. Although the subtropical ridge will be weaker and the center moves into New Mexico, it will still be the dominant feature across the region. chance of rain Saturday afternoon and evening are still at most 10-20%, but increase Saturday night to 20-30% across the Phoenix area as there are indications of a weak mid-level disturbance moving northward into southern Arizona. This unfortunately is of high uncertainty at this point. However, if some convection does get going Saturday night, forecast soundings show 1000-1500 J/kg of elevated storm energy. We will have to watch for any signs of the CAMs picking up on this potential as it could result in some localized strong wind gusts and/or a low-end chance of heavy rainfall. Temperatures Saturday are also anticipated to drop another couple of degrees from Friday with lower desert highs mostly between 102-106 degrees.
This is the plain-text edition, decoded without AI so it loads anywhere. Read the whole Phoenix discussion at /o/PSR/, see what changed since the last one, or open The National Desk for where the weather is today.