San Diego County Hits Record-High Temps In Alpine, Ramona

MAUREEN CAVANAUGH: Our top story on Midday Edition, with a heat advisory, high humidity, and a hurricane traveling up Baja, San Diego is ending the summer of 2014 with a bang. We will be seeing inland temperatures over 100∞, near 90s near the coast, with high humidity for the week. The big weather question for the moment, is when will it cool down? There are other questions, will this community decrease our chances of wildfire the season? And can we expect good rainfall in the next months to ease drought? I would like to welcome my guests, Dan Cayan and Alex Tardy. Alex, let's talk about the hurricane that slammed into the tip of Baja last night. Was that the strongest hurricane to hit Baja? ALEX TARDY: It is a category three hurricane, not the strongest, but the strongest in some time. It has already weekend, so to speak, down to category one but still, ninety mile-per-hour winds. It is moving over Baja now. MAUREEN CAVANAUGH: What is the projected path? ALEX TARDY: The path is due north toward Southern California, but to fear towards the right towards the later part of the week on Thursday. MAUREEN CAVANAUGH: How far up Baja is a going to go? Rosarita beach, Ensenada? ALEX TARDY: Close to that area, but it will start turning right before it even makes it. What is left will miss southern California and move toward southern Arizona and Mexico. MAUREEN CAVANAUGH: Will it have an effect on our weather? ALEX TARDY: A little bit. It will increase humidity, and moisture that fuels the thunderstorms we saw in the mountains a week and a half ago. We will get higher moisture levels and some cloud cover. MAUREEN CAVANAUGH: When you hear about this kind of moisture being brought into our region, the thunderstorms and the moisture that the inland areas they be getting from this hurricane, is it good news for the drought? DAN CAYAN: Well, I think we are fixed on the weather in the winter. For wildfire and human comfort, the weather in the late summer and fall is really critical. Actually, for wildfires, we do not want to see Santa Ana winds, which are dry and windy situations. As far as drought is concerned, it is really the winter water delivery that we are worried about. MAUREEN CAVANAUGH: Alex, you said with this hurricane degrading and moving toward the east, we will still be getting some humidity from it, but where's the humidity coming from that we have now? Why's it so humid here? ALEX TARDY: I think people have been asking that all center, that's a good question. There are a couple of things going on independent of having a tropical system. We just had a tropical Norbert that felt like Florida. Our sea surface temperatures have an above normal, especially in the Baja region. All the way up to the California bite, several degrees above normal, that is part of what has helped keep the minimum temperatures elevated, and it also keeps the humidity. It raises the dewpoint temperature that makes it feel uncomfortable. MAUREEN CAVANAUGH: The same event, the fact that the water is so warm is not only causing humidity, but also warmer than usual temperatures? ALEX TARDY: Right, in the immediate coast, places like Carlsbad and San Diego are really affected by the sea surface pictures being warm. Inland areas really feel the effect of the tropical moisture, which elevates moisture levels and minimum temperatures, and even when you're not hot in the day, but we have seen lately, El Cajon hit 105 yesterday. Even when you're not that hot, you feel uncomfortable with that tropical moisture. MAUREEN CAVANAUGH: What is it that is keeping it so warm at night? Usually even if it gets hot during the day, and less the sun goes down, and we sort of pick up a seabreeze, I am not feeling it. ALEX TARDY: You are not the only one, I've been running my air-conditioning and I live in Carlsbad and I can see the water. Again, it's the dewpoint temperatures. It's a measure of how much moisture the atmosphere can hold. You cannot lower the picture below the dewpoint temperature. We have seen dewpoint around seventy. That means you cannot lower the temperature below seventy without introducing drier air from elsewhere. MAUREEN CAVANAUGH: We've been hearing about things getting warmer in San Diego, should we start to expect our summers to be this warm going into the future? DAN CAYAN: Eventually, within the next decades, we're certainly looking at my projections that indicate more heat waves, longer and more intense. An interesting signal that we have seen the last couple of decades is the warmer moisture nights that Alex was describing. Not only daytime heat symptoms, but also lasting to the nighttime. MAUREEN CAVANAUGH: Alex, is there any kind of silver lining in this? Does the moisture that is coming up in the community and lingering over San Diego because the warmer ocean temperatures, does it make it less likely we will see it wildfire this season? ALEX TARDY: That is a good question. In Orange County, with the ongoing wildfires, the answer is no. With high humidity, it influences fuel moisture in terms of grasses and small vegetation. It is not do anything to trees and oaks that burn hot. Right now, those are really stressed. Elevation is below 4000 feet, they are stressing levels that we have not seen before. What helps is the monsoon rainfall, that can reduce and delay fire threat. Once we get Santa Ana winds, all bets are off, because we are in a three-year running drought. It gets dry immediately. MAUREEN CAVANAUGH: Let's talk about the drought. This is the third year of drought in California, how does this drought stack up against the California drought you have seen in the past? DAN CAYAN: It is one of the most extreme, but is not the most extreme. They are certainly examples in the observational record that rival or even our drier than this. But I do not want to discount this, we are about a years worth of precipitation below when you accumulate the results of the last three years, which of course means that in order to climb out of the drought, we will half to make up a pretty good deficit. MAUREEN CAVANAUGH: The most recent drought in the area that may be in people's memories is the one that was in the late 80s and early 90s. How long did that go on? DAN CAYAN: Statewide, that was an episode that lasted about six years. 1987 through 1992, there were interludes of modest precipitation in between, but it was definitely a long, dry spell. It took a year that was pretty wet to climb out of it in that case. MAUREEN CAVANAUGH: Were we a year behind precipitation back then, or is this drought drier? DAN CAYAN: This is drier when you consider the three-year tally. This one, especially the last year and perhaps the year before, we have been excessively dry. That drought was also in its long-term effects pretty severe. MAUREEN CAVANAUGH: Even if we got drenching rainfall this winter, you don't think it likely that we get out of this in one year? DAN CAYAN: Drought has a lot of symptoms, some are shorter and some are longer lived. In order to recover reservoir levels and soil moisture, generally that deeper water stock takes a couple of years in many cases to recover. This dryness has been very extreme. Some of the most extreme wet winters would probably help a lot if we had one of those in the next winter, but the jury is out on that. MAUREEN CAVANAUGH: The jury is out, because for one reason, nobody can seem to make up their mind about El NiÒo, whether it is coming or not, or whether it will make a difference. What do we know about that? ALEX TARDY: Blame it on El NiÒo, El NiÒo is not making up its mind. El NiÒo has not really developed. There are warm ocean temperatures near the equatorial ocean, we have been observing that since spring. But it flatlined and leveled off. We are expecting it to recover into a weak El NiÒo this winter, but the issue is, the El NiÒo signal does not guarantee wet weather here for any part of California, Southern especially. You need to get into the stronger El NiÒo, and we've only had a few of those in the past. 97 to 98 is one of the big ones, where we had a lot of water. In order to have a drought buster year like Dan is talking about, we saw that in 1978 after the horrible drought of seventy-six and seventy-seven. Forecasting those is quite difficult. We don't see a signal of a sure thing for this El NiÒo by any means. We expected to be weak, and the variability of rainfall by similar El NiÒo's is very extreme, to very dry years, and very wet years like 1978. MAUREEN CAVANAUGH: So it does not mean anything in terms of when it is mild like that, about how much rainfall we will get, we have to wait and see? ALEX TARDY: It is not the main player when it comes to that. There are other signals going on that we don't quite understand. There are other variables that go on that we do not understand. MAUREEN CAVANAUGH: How has California gotten out of drought in the past? DAN CAYAN: Is the really wet, cool seasons, and in some cases, they begin as early as November, and in other cases, things have not broken loose until January or February. Our state, amongst the United States, is probably the most volatile, meaning that a lot of our rainfall comes in a handful of storms. In many cases, it's a handful of big storms. What we will be watching this winter is looking for extensive westerly wind systems that deliver a lot of precipitation in three or four days. If we get four or five of those episodes, we will be doing okay for the next winter. MAUREEN CAVANAUGH: Alex, when will the current heatwave be over? ALEX TARDY: We are in the middle of it now, and in fact, on Tuesday it could be even warmer on the immediate coast, only because the hurricane to the south. The wind on the north side of the hurricane blows East to West, which in a sense gives us offshore flow, but we don't like the word offshore flow, because that shuts off air-conditioners. Free air conditioning with the Pacific Ocean, that is the conditioning I'm talking about. Tuesday looks at the peak. Wednesday we will feel some relief, but with the humidity you will not notice much relief. We're not going to see big relief until the end of the week, Thursday or Friday, you'll start noticing the rain there building, clouds coming off the oceans, and cooler into the night, and a little bit cooler in the day. MAUREEN CAVANAUGH: And the long-range forecast going into October? ALEX TARDY: It has been a broken record, it keeps us above normal. Since January, the state of California is the warmest it has ever been. January to August, the warmest we have ever seen, with a few exceptions. It depends where you look, but statewide, we are running warmest. The warmth is a bigger story than the drought so far, but the drought says a lot. We have been really warm. The trends to continue above normal until fall. MAUREEN CAVANAUGH: There is a heat advisory in San Diego and a wide area of Southern California. Is this dangerous weather? ALEX TARDY: It can be, if you and I take the cautions and go with air-conditioning and not going for a 3 mile run at 1 o'clock in the afternoon, we will be fine. But for those who have other conditions, older and younger, and those working in the elements and don't get a chance to take a break as much, it can be very dangerous. The symptoms of heat exhaustion and stroke can be subtle. You might just think I'm sweating a lot, it is really hot today, and it can lead to other things. A lot of times it can be out doing activities, and they are fine and running around, and that night they are up in the morning, vomiting or not feeling well, because the symptoms can take that long to set in, where they are dehydrated or have heat exhaustion. MAUREEN CAVANAUGH: So it is more than a topic of conversation, they should take today, tomorrow, and Wednesday quite seriously when it comes to outdoor activity? ALEX TARDY: Definitely. Worldwide, heat is the number one cause of mortality in terms of phenomenon. Heat can be serious if you do not take precautions and take it seriously. MAUREEN CAVANAUGH: Throughout San Diego, cool zones will be open today and tomorrow. We have a list of these air-conditioned public spaces you can spend the afternoon and cool off. You can find that on our website. Thank you both very much.