First heatwave of 2026 hits after soggy Monday

First heatwave – A rare rainy June day wraps up this Monday, but the weather flips quickly. Showers fade overnight, dry conditions take over Wednesday, and a 3–4 day heatwave is likely starting Saturday with First Alert Weather Days Sunday and Monday as temperatures climb into

By Monday afternoon, the rain is still moving across the region as an upper-level low pushes through. It’s the kind of June day that feels unusual for this time of year: a steady, gray reset, with a chance of a few more light showers before the sky clears.

Overnight, the rain dies down. Tuesday stays mostly in the light-showers category, then the forecast turns decisively drier. Wednesday marks the start of a longer stretch of dry weather.

The first message here is simple: the rain won’t last, and it won’t be a soaking. Forecast totals are expected to stay below 1 inch for most of the area west of the Cascades. and below 1/2 inch for many locations. If temperatures are going to be cool and showery for any part of the week. this doesn’t look like the system people hope for when they’re craving a bigger reset.

Then comes the change that will make people feel it fast—day by day.

From Thursday through Saturday, afternoon temperatures gradually rise under sunny skies. The rise isn’t a sudden cliff. It’s more like the gradual climb you notice when you check the forecast and realize you’re switching plans without really meaning to.

The heat itself is expected to arrive about 6–7 days from now, with a likely 3–4 day heatwave from Saturday through Tuesday. Temperatures are expected to peak in the 96–99 degree range Sunday and/or Monday.

Those two days are being labeled FIRST ALERT WEATHER DAYS for the very hot afternoon conditions.

In the Portland area, the definition matters. A heatwave is generally considered 3 days at or above 90 degrees, or at least one day at or above 95 degrees. The 95-degree threshold is described as the point where many people shift from “yeah. it’s hot but no biggie” to “this is the kind of heat where I’m going to change what I do.”.

Record heat is also part of the pressure building over the weekend. Daily record high temperatures are likely to be set on both Sunday and Monday. Sunday is expected to break through the last remaining sub-90° June daily temperature record. There’s no other June day with such a low record high temperature. Records are highlighted for both the PDX airport and Downtown Portland, with Saturday through Monday marked at both locations.

What drives the jump is a ridge of high pressure building just offshore of the West Coast over the weekend through about next Tuesday. The event won’t be described as long-lasting or historic—but it will get hot. The pattern is expected to be centered slightly to the west. including an indication from the 500mb chart from the Euro AI ensemble average for next Sunday. the 14th.

The atmosphere over the region is also expected to be unusually warm. The 850mb Euro ensemble temperature is shown with a maximum right around +20 or slightly over Sunday and Monday, possibly into Tuesday morning.

The warming at the surface is tied to easterly flow off the Cascades. A cross-section from the WRF-GFS model shows “perfect” easterly flow near sea level up to 5,000′. The circled yellow area on the model spans late Saturday through late Monday. describing air blowing down off the Cascades and warming as it compresses heading downhill.

Sunny skies finish the recipe: temperatures begin to soar Saturday (probably right around 90 in the western valleys), then peak Sunday and Monday.

Portland’s forecast pattern is reinforced with a look at the 6-hr maximum temperature in Portland from all 51 Euro model ensemble members, showing peak temperatures those same two days. For that reason, the forecast is calling both Sunday and Monday First Alert days due to the extra heat.

There’s also a caution built in. One weather tool used is the NBM (National Blend of Models), and the National Weather Service relies on it heavily. The forecast notes it has been running a bit too warm in previous warm spells this season. That’s part of why the forecast raises the possibility of higher numbers while holding back from certainty. The question hanging over the weekend is whether Portland International Airport (PDX) reaches 100 degrees—possibly. but not expected to get quite that high.

Heatwaves in this area are described as among the easiest events to predict: they’re usually sunny. and forecast temperatures stand out compared to normal. The models are said to be in good agreement on this event. with the main uncertainty being whether the region peaks at 96° or possibly makes it all the way to 100°.

Between the rain on Monday and the heat on Sunday, the rhythm is what’s most striking. First comes the soggy afternoon and a rainy June day that’s “somewhat rare.” Then showers taper overnight. drying out begins Wednesday. and by Saturday the forecast is already shifting toward the kind of heat that changes how people move through their weekend.

If you’re planning ahead, that’s the moment to act: have a plan to stay cool later this weekend and early next week.

There’s also a practical reason the forecast is leaning so hard on detail. KPTV says it is pushing more into the digital world, producing far more content than in the past. The outlet’s meteorology team says written blog posts like this are now generally published only for severe weather events—severe/stormy/snowy/icy—or when a regular update would be unusually boring.

For viewers who want more granularity. KPTV promotes two additional ways to get detailed weather information: FIRST ALERT WEATHER EXTRA SHOW (FAWX). described as a DAILY (most weekdays) weather show at KPTV. It’s typically 12–30 minutes and airs LIVE at 7 p.m. on the FOX 12 OREGON streaming app. with older episodes posted on the web page at www.kptv.com/video-gallery/weather/first-alert-weather-extras/. The show is also described as posting on the web page typically by 8 p.m. or so if it isn’t watched live.

The other option is the FIRST ALERT WEATHER PODCAST. The station says it records an episode most Wednesdays or Thursdays at 7 p.m. streaming live at the same time on the FOX 12 WEATHER Facebook page so questions can be asked. It’s described as typically being on the web page and app within about 1.5 hours. with the link at www.kptv.com/podcasts/weather/. The outlet says the podcast is also played on the FAWX show.

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