PNW Thunderstorm Outbreak: Uncertain for Western WA

Ajouté : 2026-05-28

[00:00:00]Good morning, Western Washington, and happy Wednesday. I'm Matthew Fab with Western Washington Weather. We've got some pretty interesting weather to talk about here over the next couple of days, especially the big thunderstorm potential for Eastern Washington and the Cascades. It may be putting Western Washington on the edge a little bit.

[00:00:15]We'll talk about that here in just a moment. Starting here with the satellite imagery, you can see it's a pretty nice morning across most of Western Washington with clouds for the coast and areas from Olympia southward. You can see most of the rest of the region is nice and sunny this morning. And then you can also see that there are some clouds across Eastern Washington, parts of Oregon and Idaho as well.

[00:00:34]Now, taking a look at the radar, you can see a few showers up there in Northeast Washington. Nothing significant. There are going to be some thunderstorms across some of this area today, so we'll take a look at that as well.

[00:00:42]Starting here with the overall pattern, you can see this upper-level low over parts of California and Nevada. That's what's going to just kind of hang out here and bring the big chance of thunderstorms as we go into Thursday.

[00:00:53]You can see it's just sitting here and it's going to try to pull some showers up here across parts of Eastern Washington and up into the Cascades. You can see we have a bit of an interaction with another trough here as we go into the weekend, but then that ridge builds back in as we go into Saturday and Sunday. You can see that ridge really strengthens there to our north as we go into the beginning of next week. How long this lasts is a little bit questionable, but I don't think it lasts all the way through the week there. So, you can see you have that ridge building to our north, bringing us some pretty warm temperatures possibly as we go into Monday and Tuesday of next week. But, that will likely cool off as we go into the rest of the week. So, we'll keep watching that as well. Starting here is it again with the precipitation type forecast, you can see the chance of thunderstorms today across parts of Eastern Oregon and parts of Idaho.

[00:01:38]And then you can see as we go into Thursday, you get more chances of thunderstorms as all this stuff moves up north across Eastern Washington, all associated with that upper-level low.

[00:01:47]And then you can see we're a little bit unsettled there on Friday. And then Saturday, we're mostly dry. Sunday, we're mostly dry. We're dry Monday off into Tuesday as well. But, you can see there is some precipitation way offshore there as we go toward Monday that may be starting to move toward the area. Now, looking at the winds at 18,000 ft, 500 millibars there, you can see kind of this donut shape here is that upper level low, and it just hangs out here all the way through Thursday. You see this flow that pushes up from the south.

[00:02:13]That is going to bring some of those thunderstorms to western to parts of eastern Washington, the Cascades, maybe visible from western Washington, but might not necessarily impact us. And you can see that that starts to push off out of the area as we go into Friday there, and we get impacted by a bit of an another system moving in here. But, that's the pattern that's going to be causing this. Now, looking at the Storm Prediction Center Severe Thunderstorm Outlook, you can see the day one outlook showing that marginal risk for parts of Idaho, over toward Idaho Falls and Pocatello, all the way off toward eastern Oregon near Bend and areas like Burns and all that as well. That's where the chance of thunderstorms is today, but look at tomorrow.

[00:02:52]You can see most of northeast Oregon, the Idaho panhandle, and most of eastern Washington in that marginal risk for severe thunderstorms. Um and that's something we have to watch pretty closely, and we'll take a look at that.

[00:03:02]Starting here with the lightning flash density forecast on the European model.

[00:03:05]Looking off through today, you can see good chance of thunderstorms for some areas around Boise and eastern Oregon.

[00:03:11]That continues as we go off into tonight, and you can see that diminishes. And then, as we go into Thursday morning, excuse me, you see all these thunderstorms start over parts of eastern Oregon. And then, look at some of these storms across parts of the Cascades as going to the middle of the day. And then, look at eastern Washington. You can see just a lot of thunderstorms across possible across eastern Washington to the afternoon hours there. And even potential for some thunderstorms over the Olympic Mountains, which is something we have to watch pretty closely here for western Washington. And then, you can see as we go off into the evening, some of these storms get stronger across parts of northeast Oregon and southeast Washington. And then, look as we go to about 8:00 p.m. Still have thunderstorm activity possible over the Olympics all the way off and toward 6:00 to 8:00 p.m.

[00:03:50]there. But, look at what happens here across Eastern Washington. Look at this huge line of thunderstorms that's going to move up north out of Oregon into areas including the Tri-Cities and Walla Walla up over toward Pullman and Lewiston, and then move up toward Spokane and most areas from Ellensburg all the way to Spokane there on I-90 before kind of splintering as it moves north into the mountains of Northeast Washington. And you can see potentially some more areas of thunderstorms along the Cascades into early Friday morning.

[00:04:17]And then more storms over Northeast Washington as we go into the night there um Friday night. Um now taking a look at precipitation with all this, um you can see not a ton of precipitation. You see a potential for that thunderstorm chance over the Olympic Mountains. That would bring some rain to that area. And some of these storms bring up to a half inch to 3/4 of an inch of rain um for the Cascades. But, you can see not very much precipitation there across parts of Eastern Washington, maybe only looking at a 10th of an inch out of all these storms. So, you can see Eastern Oregon does a lot better with thunderstorm precipitation. So, there is inherently a bit of a fire risk with some of this lightning because you're only going to get a 10th of an inch of rain or so. The Northeast Washington uh Cascades, some of the North Cascades there do pretty well actually, getting up toward an inch of rain. So, there's not much of a fire risk up there, but you can see the rest of the area maybe only getting a 10th of an inch with a ton of lightning moving through. So, something to watch there as well.

[00:05:13]Now taking a look at the simulated radar here. This is the RRFS um high-resolution model. And you can see it shows thunderstorms starting across Eastern Oregon as we go into about 2:00 p.m. there. And then some of these big storms start across parts of the Washington Cascades as well. You can see that line of storms that has it a bit earlier than the European model there moving up toward parts of the area like Spokane and Ephrata and almost to Wenatchee there. As we go to about 6:00 p.m., you can see some of those storms strengthening, kind of a big line there from way up in Northeast Washington toward Colville all the way down toward Eugene, Oregon.

[00:05:48]And you see all these storms in the Cascades as you go to about 9:00 to 10:00 p.m. there. And then as these move toward Western Washington lowlands, they weaken into just areas of rain, maybe a little bit of action around the Olympics there. And you can see the same thing happens and weakens as it moves toward Western BC there. And then you can see just a chance of rain at times overnight across Western Washington with the dying front there. And then as we go into Friday afternoon, you see another chance of storms for Northeast Washington, parts of Eastern Oregon, and Eastern Washington Um if we take a look at the total precipitation here on the RRFS model, you can see this really may have some good precipitation for the Oregon Cascades. Um again, not that much for Eastern Washington, though this is showing up more toward a quarter inch for some of the areas under the big thunderstorms, which would be a little bit better in terms of uh fire risk and stuff like that. And you can see maybe up toward an inch or so with some of the big storms in the Cascades, so that's something to watch as well.

[00:06:41]Now taking a look at the high-resolution rapid refresh model, you can see it also has those storms starting across Eastern Oregon about 1:00 to 2:00 p.m. And then those storms start to move north and develop across parts of the Cascades and Eastern Washington around 5:00 p.m.

[00:06:54]there. Look at this line across parts of the Oregon Cascades, and that all is a little bit more of a uh formed line than you have across Eastern Washington. So the high-resolution rapid refresh not showing that uh like Pullman Pasco line there. Um but it is showing more of a line of storms moving up into the Cascades and the eastern slopes of the Cascades there. And this also does show some of these thunderstorms moving off into the lowlands as you go to about 9:00 to 11:00 Thursday night, and you can see that heavy rain at times as well. It weakens as it moves into the lowlands, but these would be thunderstorms across the lowlands if this were to develop like the high-resolution rapid refresh model is showing. And then you can see that weakens and moves off to the north as we go to about 5:00 a.m. there. Now taking a look at total precipitation here, and as you'd expect with this setup, a bit more precipitation, especially in the mountains, over over an inch for some areas, and maybe some precipitation for some areas around the sound as well, if that were to verify. But again, not much precipitation with any of these smaller storms on the high resolution rapid refresh model that move up across parts of Eastern Washington. So, a bit of a mixed bag still. Have a lot of kind of nowcasting to do in tomorrow morning's video. Um but as far as the ingredients for thunderstorms, um they are definitely there. You can see this is the CAPE index, which is convective available potential energy. That's basically your fuel for thunderstorms and how much there is. Here across the Northwest, we're usually excited about getting CAPE numbers around 400 to 500.

[00:08:19]Here you're looking at a 1,000 to 3,000 across Eastern Washington and the Cascades and Eastern Oregon and parts of Idaho as well. So, it's safe to say the ingredients for the storms are definitely there. Um if you also look at um some of our dew points, you can see it there are some pretty moist dew points across the Cascades and in some other forecasts here, which we pull up across um Eastern Washington as well.

[00:08:43]Let's go to Wednesday afternoon. And you can Thursday afternoon there you can see you got dew points across um the Cascades and across parts of Eastern Washington in the upper 50s to low 60s, maybe even some mid-60s up there. So, it's definitely moist out there as well, which will help with some of these storms.

[00:09:00]And then looking at temperatures, there's a bit of a temperature roller coaster coming up here. We'll end the video on this here. You can see highs today likely in the mid-70s across the Seattle area, upper 70s to the south, and low 70s to the north. And then the coast likely in the mid-60s. Take a look at tomorrow, though. You can see highs across the Seattle metro area in the upper 70s to low 80s, a few mid-80s possible out there. North of Seattle, you're looking at highs in the mid to upper 70s. And then take a look at Eastern Washington. Some more fuel for those thunderstorms, some really warm temperatures during the day with highs in the upper 80s to mid-90s. But then take a look as those thunderstorms move through, temperatures drop across the region, and Eastern Washington drops about 20° in some spots to the mid-70s to low-80s. Um, so 10 to 20° temperature drops for Eastern Washington and up to 20° cooler across Western Washington there um from Thursday into Friday with Friday's highs only in the upper 50s to mid-60s across Western Washington. On Saturday, we get back into the mid-60s across the region. Start to rebound a little bit more on Sunday with highs up into the mid-upper 60s, some low 70s from Seattle southward. Then big rebound as we go off into Monday with that ridge building to the to the north and you can see highs in the low 70s from Seattle north and upper 70s to low 80s from Seattle southward, maybe some mid-80s around Portland. And then look at what we're seeing on Tuesday, June 2nd. So, that's just under a week out. So, take this with a little bit of a grain of salt, but look at those highs across the region, likely in the mid-80s there and maybe even some low 90s across parts of Western Washington, Western Oregon there on Tuesday, June 2nd. And then that does start to cool down as we go off out to about a week from now there, Wednesday, the 3rd of June with those highs dropping to the mid-upper 70s. So, overall, could be some nice weather coming up, but you can see as we go way off toward Friday and Saturday of next week, those temperatures drop back down to the uh low the upper 70s or upper 60s, low 70s. So, this ridge is not going to last all week. So, we just have to watch and see how that plays out. And then taking a look at the uh temperature change from Thursday into Friday, you can see big drop for some areas across the region.

[00:11:00]Eastern Washington dropping 10 to 20° in their highs, the Cascades dropping 20 to 30° and then take a look at Western Washington as well, highs uh 15 to 20° colder on Friday versus on Thursday. So, definitely some interesting weather coming up, especially with some of those thunderstorm chances. So, for more updates on that, be sure to subscribe to Western Washington Weather. I'll have another video tomorrow morning talking about this in a little bit more details as we have more information. And then be sure to follow the Western Washington Weather Facebook group and follow me on Twitter and Blue Sky as well. I'm posting more updates on there also about this setup and everything that could go along with it. So, stay tuned, stay safe out there, and watch out for our next video here and the updates on social media. You can find the links to all of these below, and I will talk to you all later.