Rain, Snow And Thunderstorms For California. The Sunday Briefing 4-19-26

追加: 2026-05-06

[00:00:03]Good afternoon, everybody. Mark Finan here in the home weather office on this Sunday afternoon. It's the 19th day of April, 2026, and this is the Sunday weather briefing.

[00:00:14]Yeah, thought I'd give you an update because we do have rain and Sierra snow on the way and probably some thunderstorms, too. So, I just kind of wanted to take this opportunity on Sunday to help set the table for what you can expect through the week and the times that might be a little bit more active and the times you may want to maybe avoid traveling through the Sierra and that sort of thing. So, I always like Sundays when we do have some active weather to help you plan your week. Right now, boy, it's a beautiful day. This is Sunday.

[00:00:44]I'm recording this around 4:30 on Sunday afternoon.

[00:00:48]Uh sunshine, a few clouds. It's brilliant day. It's been terrific.

[00:00:52]Temperatures in the 70s. But, if you look at satellite, yeah, this is a This is an interesting satellite. We have mainly clear skies in California. Look at this big low spinning out here.

[00:01:03]And then out ahead of it is this front here.

[00:01:08]All of this is going to take quite a bit of time to come inland because the low is going to spin around out here for the next 24 hours and then finally kick inland. And it's the timing of that kick inland that we're waiting on to give us our rain and snow.

[00:01:25]So, let's take a look at the big picture. There's the way it is on the on the GFS the 500 millibar level. And as you can see, this is coming inland.

[00:01:33]It's actually a little bit more progressive than what it was looking like a couple of days ago.

[00:01:40]In other words, instead of just taking its time and spinning around out here, it actually looks as though it will kick inland during the day Tuesday, actually even early Tuesday, bringing us rain.

[00:01:51]Some showers may linger into Wednesday, but beyond that, this should be into Thursday. Yep, this is Thursday morning.

[00:01:58]Thursday looks okay. Next weekend could be a little Well, let's just say cool. I don't think it's going to be unsettled next weekend.

[00:02:06]But as you can see, we have a kind of an odd pattern here with a low here, a trough here. We're kind of in between.

[00:02:15]And then maybe something else comes our way next week about the same timing. All right, so let's get into the model details and I'm going to show you a bunch of different stuff here with the models.

[00:02:27]I'm going to start off with the closest closest view.

[00:02:30]This is the 18Z HRRR and this is at 2:00 a.m.

[00:02:36]As we head into the day tomorrow, this is 9:00 in the morning. There will be rain on the coast.

[00:02:42]Now, for those of you in Humboldt County, Del Norte County, and all the way down through Mendocino and on the coast and even towards San Francisco and Napa, we'll likely see some rain. But for the foothills and Sierra, we would likely will stay dry during the day tomorrow. You can see how this band of rain here, watch how that just kind of well, it loses its enthusiasm. But we continue to see rain on the coast.

[00:03:07]Now we're up to 5:00 p.m. and we're still dry in the valley and we're still dry in the foothills and Sierra, but yeah, rain continues as well as some snow in the higher elevations.

[00:03:17]This model only goes throughout 48 hours, so this is Monday night. We're finally seeing some rain into the valley and then this is the best rain, the steadiest rain and this is at 3:00 a.m.

[00:03:30]5:00 a.m.

[00:03:33]7:00 a.m. So Tuesday morning, the morning commute could be kind of wet.

[00:03:38]Snow in the Sierra, snow level around 5,500 ft.

[00:03:42]There will be likely chain controls on 80 and 50 uh by by well, probably before the sun comes up on Tuesday morning. So if you're planning on traveling in the Sierra on Tuesday, you can expect chain controls throughout much of the day.

[00:03:57]And then this model won't get all the way there cuz it only goes up to 11:00 on Tuesday morning, but it's Tuesday afternoon that will have the possibility likely of thunderstorms.

[00:04:07]Let's see. Does this model have This model does not have what I was looking for.

[00:04:13]Let's back this out to the regional look.

[00:04:18]And this will have the what I'm looking for, which is the severe weather and cape.

[00:04:26]Um most unstable.

[00:04:29]Cape, where are you?

[00:04:31]Surface based.

[00:04:33]Most unstable cape.

[00:04:35]So, as we head into the afternoon, um we'll likely start to see some cape here. In other words, we'll start to see the atmosphere be right to have some um some lift going on. We'll have some better looks at that here in a second.

[00:04:48]Let's go out to the NAM.

[00:04:53]And we will go back to precept.

[00:05:00]Okay, so let's see how if the NAM agrees with the HRRR.

[00:05:05]Looks about right. This is uh Monday night.

[00:05:09]And then during the overnight, yep, this is agreeing almost completely with the HRRR on timing.

[00:05:15]And then on Tuesday afternoon, this would be thunderstorms, although it doesn't really look like it there. That would be showers and periods of thunderstorms as colder air moves in.

[00:05:26]Tuesday's going to be a chilly day.

[00:05:28]And then into the day on Wednesday, yeah, not much. It's funny because a couple of days ago Wednesday was looking like the wetter day, but now because this system is pretty progressive, there will likely be a couple of lingering showers Wednesday, but if you have outdoor plans on Wednesday, that should be a better day and also looks like Sierra travel will will in much better shape.

[00:05:48]Let me go to the to the this version of the NAM and let's back up to Tuesday afternoon.

[00:05:57]Yeah, this looks better. And I'm going to switch back to Northern California.

[00:06:03]My apologies to those that may not be interested in extreme Northern California, but yeah, this is this is kind of what I would expect. And again, the time frame here, this is uh showing at 5:00 on uh Tuesday afternoon. These would be thunderstorms most likely.

[00:06:19]And let's take a look at Let's see if this one has Oh, let's just do this.

[00:06:30]And let's do this.

[00:06:36]And let's see what the sounding looks like on Tuesday afternoon.

[00:06:40]So, what you're looking at here is the the temperature aloft and the dew point aloft. You'll see that right here, they're the same, so this is a solid cloud deck.

[00:06:51]And then you have really good lift going on here. And the other thing I always look for, especially this time of year, is what's the 500 millibar temperature?

[00:06:59]And it's here's the minus 20 line, so we're down around minus 25. Yeah, anything around minus 22, minus 25 at this time of year, that's uh that's pretty good that you're going to get some really good lift. So, the thing you should be looking for on Tuesday is, let's say, let me go back to the preset.

[00:07:19]So, this is a scenario we often see during the spring.

[00:07:22]All right, you see rain overnight.

[00:07:27]And then this is 9:00 in the morning, 10:00 in the morning the sun comes out.

[00:07:32]I'm just going to guess the sun's going to come out around, you know, 9:00, 10:00 after the overnight rain. And then all that does is heat the surface and then you add a little bit of moisture, your cold air moves in aloft, and now you get thunderstorms likely with some hail.

[00:07:47]Uh don't know if this one doesn't have lightning, does it? No, it does not have lightning.

[00:07:55]Each triple R has lightning, but it doesn't go this far out.

[00:07:57]But, either way, you can see that we'll likely see thunderstorms Tuesday afternoon with lingering showers into the day on Wednesday.

[00:08:06]Let's go out to the GFS, and I'll go back to all of California.

[00:08:13]And most of the west. Okay. So, now we'll look ahead to the rest of the week.

[00:08:19]So, Thursday looks dry.

[00:08:22]Friday looks dry. I said next weekend looks kind of interesting. This is Saturday, still dry.

[00:08:27]Yeah, the models have been picking up on some Sierra activity on um on the weekend.

[00:08:37]Not too sure about that. That's Monday.

[00:08:42]Yeah, because of that odd pattern we have. And then let's see. And then this model doesn't have anything for next week.

[00:08:49]Whereas the other models do.

[00:08:51]So, uh so, for your planning purposes for this uh this upcoming week, Tuesday looks like your wet day.

[00:08:59]Rain before sunrise, then showers and thunderstorms.

[00:09:02]And uh some Sierra snow down to about 5,500 ft.

[00:09:07]Let's go to some totals, and for that I'm going to go back to the NAM.

[00:09:13]And let's zoom back in.

[00:09:18]Okay, so what's our total QPF here?

[00:09:24]About a half an inch of rain in the valley, but it will depend on whether or not you get a thunderstorm.

[00:09:29]So, for in other words, what this is showing here is maybe a thunderstorm went through here, and it shows uh 3 in of rain. Yeah, that would be extraordinary. Um, so yeah, it's it's the sort of thing that uh, I think from the rain that we see overnight, we may see 1/2-in of rain.

[00:09:48]And then, if you get a a thunderstorm, you might see another quick 1/2-in.

[00:09:53]Uh, what about snow?

[00:09:59]For Sierra snow, I think we were looking at 8 to 12, maybe.

[00:10:03]Yeah, that looks like about right. Up on the summit, 8 to 12, not down at 5,500.

[00:10:07]You get a few inches down at 5,500. But up on the summit, yeah, 8 to 12. Uh, maybe an inch or two down at lake level.

[00:10:16]That sou- sounds about right. Uh, let's see about wind.

[00:10:23]Let's see if it's going to get windy as this thing goes by.

[00:10:28]Okay.

[00:10:29]This is Monday morning.

[00:10:37]Monday afternoon.

[00:10:39]Windy in the Sierra, that's for sure.

[00:10:42]And then, Tuesday.

[00:10:46]Not too windy. Gets occasional gusts.

[00:10:49]Oh, this is interesting. See how these See this little area right here?

[00:10:55]Watch how that blows up.

[00:10:59]What the model's trying to do is pick up on outflows from those thunderstorms.

[00:11:06]Right there. Yeah, that would be outflows from thunderstorms, downdrafts, if you will. Gusting into the upper 20s and low 30s.

[00:11:14]Uh, otherwise, in the Sierra, uh, rather windy, as you might expect. So, I think I think that's um, that's everything. Um, dry in the valley and in the foothills on Monday.

[00:11:29]Rain starts Monday night in the valley.

[00:11:32]Some of the best rain will be during the overnight and pre-dawn hours on Tuesday.

[00:11:38]Perhaps a little bit of a break in the morning hours the 9:00 10:00 and then anytime between let's say 11:00 and 6:00 11:00 a.m. and 6:00 or 7:00 p.m. We'll have the possibility of thunderstorms that could have some gusty winds, downpours of course and maybe some hail.

[00:11:53]Um yeah, hail I think would be another another bet. Probably not as extensive as what we saw with the last go around uh but still another round of thunderstorms likely on Tuesday afternoon. And of course the air or snow we will have uh the snow level like I said we'll ballpark it at 5,500 ft.

[00:12:10]You'll only get a couple of inches there but uh up on the summit 8:00 to 12:00 so there will be chain controls throughout much of the day Tuesday but the roads should get cleared up for the day on Wednesday and then the rest of the week looks dry.

[00:12:23]But boy chilly um as as we go through Tuesday and Wednesday as well. That's everything I've got for you on the Sunday. Hope that helps you set the table for what you can do this week and you can work around the rain and snow that we're going to see and of course I'll have another update first thing tomorrow morning. Enjoy the rest of the weekend. I'll talk with you later.