Scorching Heat To Continue In San Diego County

Speaker 1: 00:00 A heat advisory is an effect for San Diego's inland valleys until tomorrow night. And temperatures are expected to soar in the Eastern part of the county. Borrego Springs may reach 116 degrees, but at county beaches, it's a very different story. Surface water temperatures are measuring an exceptionally cool 60 degrees. So obviously the answer is to hit the beach if you can, but here with more and better answers about our summer heat wave is national weather service meteorologist Alex tardy, Alex, welcome to the program. Speaker 2: 00:36 Thanks for having me on again, hot weather Speaker 1: 00:38 In August, usually not news, but it's getting really hot in some parts of the county. Speaker 2: 00:43 Yeah, that's right in August. That's our normal hottest period here in San Diego. So we expect to see some of our hottest temperatures, uh, and sometimes humidity too, uh, in the month of August. But what's going on right now is we have unusual hot conditions, even above average, and that's going to affect our mountains, our inland valleys. And especially like you mentioned our deserts where temperatures will get over one 15 and even for their that's above average. Speaker 1: 01:14 And does this heat bring fire danger? Speaker 2: 01:17 Oh, it sure does. Unfortunately. So last week we had more moisture around, uh, which we call the monsoon and that helps suppress the fire activity. The fire still start, but they don't burn as fast. Now that we have these high temperatures above average warmer than they should be the full sunshine and the lower humidities to less moisture, those ingredients, um, they're actually reflected in the fuel levels. The moisture of the fuels just the past few days is plummeting again, back to record levels. So fire danger is elevated. It's definitely there Speaker 1: 01:55 Air be a concern during this rise in temperature. Speaker 2: 01:59 Yeah, a little bit because what happens with the air quality when you get into these heat waves or these dome of high pressures that we call it, it tends to trap and, and suppress a lot of the movement of the air vertically. So that does two things. It smushes our Marine layer further down, uh, near the beaches. So the low clouds and fog hangout down there, but it also acts to put a lid on our air even where it's sunny and clear, and that can cause stagnation buildup of ozone and just poor air Speaker 1: 02:31 Quality. Now in most areas of the county, it feels like it's been more humid this summer than usual. Is that the case? I wouldn't say Speaker 2: 02:39 More than usual. We've, we've seen a trend though. Since 2012, we've been tracking very closely. And in each summer, July, August, September, we've seen a trend where humidity has been above, you know, like a 30 year average across our region. Uh, one of the peaks was back in 20 18, 20 19. Um, the two things are conflicting each other right now. So we, we did see Mon monsoon moisture come up last week and that's probably the humidity you felt, but we have the ocean temperatures that took a nosedive. And so that kind of offsets some of the local humidity as well. Uh, so we have two things conflicting and right now we're, you know, out of the monsoon briefly and we have those cool water temperatures. So we're not quite as humid as we really could be or have been in the past few years in August. Speaker 1: 03:29 And what's causing these very cool ocean temperatures. Speaker 2: 03:33 Well in simple terms, we call it upwelling and it's a very natural occurrence along the coast. When you get a northerly winds along the coast, it helps turn up the water and we'll bring up that colder water underneath the past three years in the summer, we've seen very little, um, effective upwelling. Uh, most recently we just saw temperatures drop about 10 degrees Fahrenheit on the coast, but believe it or not off shore well off shore. There's still what we call a Marine heat wave. There's still water. That's much warmer than it should be. That's similar water to what we've seen in the past three summers. So right now we're definitely not complaining about this recent upwelling cooling because there's still a lot of warm water and it could change rapidly to the warmer side in a short notice, especially in August and September Speaker 1: 04:22 Now, while it lasts is the cool water helping us keep nighttime temperatures more comfortable along the coast, Speaker 2: 04:30 Uh, kind of a combination of things. So the, the cooler water directly affects our air temperature, especially right near the coast. So it's like having an air conditioner. Um, it also, when the water is cool, believe it or not, even with clouds and Marine layer, the McGee ness is less. And so in essence what you're saying, yes, correct. If it helps at nighttime under clear skies and dry air like we have now, it helps at night to cool it off. So the one good thing about this heat wave is the Knights are relatively cool inland and on the coast, but the days are warm Speaker 1: 05:05 And okay. So we have to get to it. Remind us when we should start feeling Santa Ana conditions kick in. Speaker 2: 05:12 Yeah, we have to mention it. Don't we? Um, so on average we see mid to late September where our first Santa Ana starts to influence our area and that's directly associated with the jet stream that starts bringing a little bit cooler air to the Northern Rockies in earnest. It's typically in October. And there's really no reason this year, why we wouldn't see average or if not slightly above average. So more than normal Santa Ana wind events is we go into the fall. It's going to be a critical time. This fall for fire weather conditions. What's the outlook for the rest of August, though, for the rest of August, we look to have above average temperatures warmer than normal temperatures. We also look to see potential for more monsoon activity. That's, that's what brings the muggy ness, but that also brings some beneficial rain to our mountain areas. It looks like in the middle of August, we could get back into that. Speaker 1: 06:08 Okay. I've been speaking with national weather service, meteorologist Alex tardy as always Alex, thank you so much. Thanks much.