Laura Weingartner Alright, that should be enough time. Alright, hi everyone, I'm Laura Weingartner, a science communicator here with ACCAP, just filling in for Ed Plumb today. Welcome to the October edition of the Alaska Climate Outlook Briefing. Today's event is being held at the International Arctic Research Center, here at the University of Alaska Fairbanks on the Troth Yeddha Campus. The Alaska Center for Climate Assessment and Preparedness, also known as ACCAP, is hosting this event. ACCAP is part of the Regional Integrated Sciences and Assessments Program, which is funded by the NOAA Climate Program Office. We've been working here in Alaska for around 20 years with the goal of improving the ability of Alaskans to adapt to a changing climate. Some basic Zoom logistics. You've all been muted, and your video is disabled, but we'll have some time at the end for Q&A, and at that time, I'll allow it so that you can unmute yourself and turn on your video to ask questions. Otherwise, you can drop questions in the chat as Rick is presenting, and yeah, we'll bring those up during the Q&A. And today's webinar is being recorded, just so you're aware, and the recording will be posted on the ACCAP website, and we'll also send out an email with the link to the recording. And Ed, who is currently out of town, will be doing that, so those, he'll send those out a little bit later than normal. But they will be coming to your inbox. And with that, it's my pleasure to introduce today's speaker, Rick Thoman. Rick is the Alaska Specialist with ACCAP and a long-time Alaska resident with extensive experience in Alaska weather and climate. His work focuses on climatology, meteorology, and science communication, with a particular talent for putting current weather and climate conditions into historical context and making that information understandable and useful for communities, decision makers, researchers, and the media. So, thanks, Rick, for being here, and I will hand it off to you. Rick Thoman All right, great. Thanks very much, Laura, and thanks, everyone, for taking time out of your Friday to join us for the October edition of the Climate Outlook webinar. We've been doing these monthly Outlook webinars for, a dozen years now, so. Hope that this one is, helpful to you. So, slide. All right, so here's our outline for today's program. Same as we do every month. We'll start out with just our one slide on reviewing what we're trying to do with monthly and seasonal climate forecasting, take a look at some recent happenings. Then kind of review what's happened with the climate system, how past forecasts have done, and we'll take a look at some of the tools that we have to construct the upcoming monthly and seasonal forecast, and we'll finish up with the outlooks. That were just released by NOAA's Climate Prediction Center yesterday morning. So The Climate Prediction Center in College Park, Maryland is the primary NOAA facility for forecasting from about 2 weeks into the future on out into about a year into the future. Weather Service forecast offices and the River Forecast Centers, mostly work in the, you know, kind of the right now to, a week out time frame. Okay, so here's our one slide on climate forecasting basics. So, unlike the weather forecast on your phone. Most climate outlooks are done in relationship to some long-term, quote, normal. Current international standards is the 30 years 1991 to 2020 as the baseline normal period. Now, typically, climate forecasts are done as categories rather than absolute values. Most commonly, three categories, so significantly below, near, and significantly above normal would be three category forecasts. Whether we're doing 2, 3, or 5, or however many categories, a feature of climate forecasts is we're going to give you the chances of all the categories that we're forecasting for occurring. Temperatures at the monthly or seasonal scale centered on the average. Precipitation centered on the median, that is important in dry climates, or in climates that have a notable dry period, because the median can significantly differ from the normal, which by long historical convention is just the average, or the mean. Now, if you're interested in what these normal temperature and precipitation ranges are, we have quite a number of sites around Alaska. That show you what those are. They're, at on our, climate graphics page. QR code there is there on the on the slide, and Laura's put the link there into the chat. All right, so recent happenings. So, we have not had any repeats so far, fingers crossed, of ex-Typhoon Merbok or Halong-type storms, but we have been impacted, by ex-typhoons in the last month. We had ex-typhoon Dujin in late September impact portions of the southern Bering Sea, and then earlier this month, Choi Wan impacted parts of the parts of mostly the Aleutians, although some impacts a little bit farther east as well, but nothing, of course, like those two big storms. Now, we've started off fairly cool across the North Slope, and we'll see partly why here coming up, but the especially the western North Slope, so places like Utqiaġvik and Wainwright and Point Lay, they have had the coldest first two weeks of October in, 25 years, so pretty impressive. coolness For the 21st century, it has not been cold by historic standards on the western North Slope. Eastern North Slope, it's running a little bit below normal, but there's been, several first two weeks of October in recent years that have been as cold or colder. Now, right now, if you're in Southeast, you already know this. First major, atmospheric river of the autumn, to impact southeast, Alaska over the last, 36 hours or so. Widespread 3 to 6 inches. of rain, at sea level, and, of course, it is the it is the, rainy season in Southeast, so. It's seasonally not unexpected, but this is the first real big one of the, of the season. Okay, so now let's start out. What's happened around Alaska, and how did previous outlooks from the Climate Prediction Center work out? Alright, so starting here with temperatures, these are using our the ERA5 climate reanalysis model, and I show these graphics every month, courtesy of our colleague, Dr. Brian Brettschneider with the National Weather Service in Anchorage. And, so what this is showing us is how Temperatures for September on the left, and the July through September late summer season on the right, how they worked out relative to the categories that we are trying to forecast. Remember, climate outlooks, we're forecasting categories. So, on these graphics, the white space are areas that fell into the near-normal category for the month or the season. The, kind of the reddish areas are areas that were in the significantly above-normal category, and the blue areas were in the significantly below that 30-year baseline normal. category there. So, with that background temperatures on the left, you can see, effectively all of the land area of Alaska was either in the near or significantly above normal category. For September, average temperature, certainly a preponderance of southern Alaska, say, Alaska Range and southward were in the above normal category. north of the Alaska Range, and probably more in the near-normal category. Now, for the season as a whole, though, a little bit different story. We actually have some areas, especially in southwest Alaska, that did wind up in the significantly below normal category. A fair chunk of the state, though, was in that near-normal category, but the North Slope in particular, portions of the Copper River Basin and eastern interior down into Southeast wound up in the significantly above-normal category for the three months July through September. Now, same idea with precipitation. Here, the greens and blues are significantly above normal. The yellows and oranges significantly below normal, white space near normal. September precipitation. On the, on the, left-hand side here, you can see, much above nor in that significantly above normal category over much of the, state north and west of the Alaska Range. A few exceptions there in the Y-K Delta, as well as in Northeast Alaska. Those blue colors indicate that this past September was the highest in of any September in our climate analysis model since 1950. In fact, for Fairbanks, this was the highest September precipitation in 101 years. We have to go back to 1925. Find this as much rain as we had in September, but very sharp gradient there across the Alaska range. You can see much of South Central there was in the significantly below normal category. That west to east split like that with a much above normal there in the north and below normal in the south, that is indicative of enhanced westerly winds, west to southwest winds aloft, bringing in precipitation into the interior, but the south central areas, Kodiak Island, closer to the high pressure aloft. So this is not an uncommon pattern for precipitation, especially in the warm season. The right-hand side is the late summer precipitation. Again, very dramatic contrast. Again, much of Alaska wound up in the significantly above normal category, but just like we saw in September, a very sharp dividing line. This time extending from basically the Matanuska Valley northeast into the upper Tanana Valley. as well as portions of, or much, really, of southeast Alaska there, in the significantly below normal category, and we actually have Moderate drought being analyzed by the. by the U.S. Drought Monitor in the Upper Tanana Valley, this continuation of the very dry weather, that, helped to fuel the Mukluk Fire in Tok in August. There has been not much precipitation in the Upper Tanana Valley, over the last few months. All right, so now we're going to take a look at how the Climate Prediction Center outlooks worked out here. Instead of using the climate reanalysis model, we're going to use the data that is available from the long-term climate sites that we have enough observations for. So, starting with September temperatures here, the underlying color field is what the Climate Prediction Center forecast in the middle of August outlook, and then the shapes there indicate how each of the long-term climate sites that we have data for wound up actually working out. So, you can see, just like in the climate analysis model, there's a whole lot of near-normal categories were observed. But with some above normals there, especially their Copper River Basin and then down into Southeast, Eagle also in the significantly above normal category. So, all in all, in the area that CPC made a tilt, so that's any of the oranges shades there, about 40% of the station observations were in the correct category. Now, it's a three-category forecast, so that means if you randomly guessed, you would expect to get, on average, about one-third right. So, 40%, that's a little bit better than random guessing a skill score of plus 10. Zero would be, just random guess score. Okay, now, precipitation. Precipitation here, quite a good forecast from the CPC, in mid-August here. You can see that the CPC correctly had that, the west-to-east area there of above-normal precipitation. That one that worked out quite well. The forecast maybe was displaced a little bit south. There, but all in all, this is a pretty good forecast. Of course, there you see, as in the reanalysis model. Fair number of stations wound up in the significantly below normal category, but CPC did not make a forecast for that. All in all, based on the observations within the area they made a forecast for, 78% correct, skill score of 68. That is really good for precipitation forecasts, especially because This area the area that they forecast for is not just a little tiny area that one or two stations verified in. Covered a pretty large chunk of territory here, and that worked out pretty well. Now, turning to July, August, September, late summer season, forecast was this is the forecast, the underlying color field that was made in. in mid-June, and so not such a good forecast here. You can see most of the state, except for portions of the North Slope, eastern Brooks Range, northeastmost interior. Favored the significantly above normal category, and that only worked out in a few of the observations there, and Particularly there, notable, with a fair number of sites there falling into the significantly below normal category for the 3-month season. So that's a two-category miss. That's. Climate forecasters, we don't like to see those two category misses, especially over a three-month period. All in all, only three of the observation sites here that we have data for fell into the significantly above normal category. Only 11% of the sites within the area there, so it's a negative skill score, so that means, less skill than just randomly guessing here. So this was a tough one for CPC. Now, for precipitation. In this case, a pretty good, skill score there, 70%. But, all in all, a lot of the state The forecast made in mid-June for July through September precipitation did not tilt the odds, even though you can see there a lot of mainland Alaska in the significantly above normal category. On the other hand, much of Southeast fell into the below-normal category. So, where the forecast was made was actually worked out pretty well. And even did pick up Ketchikan in the southeast there with a tilt to dry. But, so this is an example, yes, the skill score is very good, but clearly. The area could have been larger and verified, particularly with the higher precipitation north of the Alaska range. But for where the CPC made a forecast, it worked out pretty well. All right, turning to sea ice. As of Wednesday, quite interesting, quite interesting here. Sea ice extent in the National Snow and Ice Data Center analysis, which is where these products are from, was reached on September 12th, and since then, we've seen quite a quite a rapid increase in sea ice extent, especially In north and northwest of Alaska, and also in the Greenland Sea on the east side of Greenland. And sea ice extent has increased almost 40% in the month and two days since the minimum there. And you can see. You can see that the kind of the orangish-colored line there. That's the 1981 to 2010 baseline normal, and close to Alaska, we're pretty close to that. On the other hand, you can see there. In the Atlantic side, except for the Greenland Sea ice extent is below normal in Baffin Bay, so between northeast Canada and Greenland, as well as north of the European Arctic over into the Kara, Laptev, and even East Siberian seas sea ice extent much less than the 30-year baseline from 1981 to 2010. When we put it all together, the daily sea ice extent is shown on the right-hand side, and I just circled where we're at now for your convenience. Total ice extent is well above where we were at last year, and especially 2024. Overall, as of Wednesday. Total Arctic sea ice extent was the 13th lowest for the date. So we were just looking at the two-dimensional sea ice, just the extent of the sea ice, sea ice extent areas with 15% or more sea ice concentration. Here we're looking at sea ice thickness. So this is based on a model. From the Danish Meteorological Institute. The Wednesday analysis, or the model output for Wednesday is on the left, and same date except last year on the right. Now, a couple things I want to call your attention to here. If you compare the thickness, so that's in the color field there, say from Greenland and northernmost Canadian islands there north towards the pole, you'll notice the ice is notably thicker, so kind of those lighter blue colors than we had it this time last year. The area of really thick ice, so that's the yellows to red colors there, remain confined to close to the Canadian coast there, and some areas, northwestern islands there, notably thinner ice than we had last year in this modeled scenario. But, because of that thicker ice. Farther extending farther north and even across the pole onto the, onto the, Asian side there, the total sea ice volume, so that's the extent times the thickness, is actually recovered, significantly from the last two years. Still very low. But in the little insert there on the left-hand graphic, you can see it's notably ticked up over what we had in 2025 and 2024. All right, closer to home. Here is the sea ice concentration analysis from the National Weather Service Sea Ice Program. Wednesday's analysis is on the left, same date last year. on the right, and you can see there we've got significantly more ice close to Alaska. There is still open water, portions of the near coastal, Beaufort Sea, but we've got. Much more ice, not very far northwest. of the, northwest North Slope coast, so not very far, northwest, Utqiaġvik and Wainwright there. And that is that is, quite different than we've had in most recent years. If you look close, you can also see we've got ice forming behind the barrier islands, as far all the way down the coast, and on the Beaufort Sea coast as well. So, both the Beaufort and Chukchi Seas sea ice extents are running, quite high for this time of year, in 2000 in. As of Wednesday, sea ice extent in the Beaufort Sea, the highest for the date since 2009, and since 2005 in the Chukchi Sea. However, if we put the two together, so basically the seas north and northwest of Alaska. Sea ice extent is higher now than any date since 2021, and that is contributing Is both contributing to and is in part reflection of the very cold start to October that we've seen on the North Slope. Nope, back one. There we go. Okay, so here is, again, so here's the combined sea ice extent for the Chukchi and Beaufort Seas, as I've been showing the last few months. Blue line is this year, green line is last year, and the thick black line is the smooth 1991 to 2020 median extent. So you can see there we are well ahead of last year, and well ahead of the. 30-year baseline median there. All of the higher years there, those thin gray lines that are higher than this year, all occurred 2021 and earlier. All right, turning from ice to ocean temperatures here, global sea surface temperatures. Graphic on the left-hand side is for the week ending October 10th. I've just circled the North Pacific for your eye. A couple of things will draw your draw your eye here. Very warm waters extending, from east of Japan, across the Dateline. That, of course, is not new. That has been there most of the time, since 2021. But one recent development here. is with, this, well above normal water, into the Gulf of Alaska now. During the summer, we the sea surface temperatures were near to a little bit above normal, but more widespread, at least offshore now, in the Gulf. Bering Sea, much more mixed, with generally. Some areas near normal, some areas a little bit below, some areas a little bit above. And north of the Bering Strait, the higher sea ice extent is showing up there. The other area that catches your eye. is along the equator there, a classic textbook El Niño signal with very warm waters east of the dateline along the equator. Notice the this extremely warm water with El Niño directly is right close to the equator. We do have some other areas, though, with really warm waters, particularly off the California and Baja coast there. Only that's Possibly or probably in part influenced by El Niño, but is not directly with El Niño. El Niño confined to that right near the equator. The little cutout there just shows some detail for Alaska. Okay, just like sea ice, we were just looking at the two-dimensional, what the ocean temperature was. Just right, you know, within a couple of feet of the surface. But we want to look at depth, so this is the upper ocean heat content slide on the left-hand side. From the Climate Prediction Center, we have This is the upper 300 meters of the water, the total, heat content difference from normal, so you can think of that as the average temperature. difference from normal in the upper 300 meters, so quite a large volume of water, and the heat along the equator with El Niño really stands out. Notice, though, west of the dateline in the tropics. In the tropical Pacific below normal heat content. Again, that is that is classic El Niño. You can see the heat in the North Pacific extending. To depth east of Japan, east across the Aleutian or east across the Dateline to south of the Aleutians and in south of the Gulf of Alaska. Near Alaska, we don't see much change this month in the total heat content. Now, I've been showing this slide here with the, with the El Niño here on the right-hand side. This is a cross-section of the temperature difference from average across the, equatorial Pacific. The way this graphic is designed, the depth below the surface of the ocean, that's the vertical axis. From the surface down to 450 meters down, and then on the horizontal axis is longitude, so this extends From, near the Solomon Islands, back in the Western Pacific, over to about the South American coast. So this is an extremely large area here that's about 9,000 miles or so. And you can see what really jumps out at you is the deepest red they have on the legend here in the eastern Pacific, east of about 150 degrees longitude, so about due south of Hawaii, all the way over to the South American coast, at depth. There is, extremely warm water relative To normal, and that is a good sign that our El Niño's got a ways to go. But notice west of the dateline, generally cooler than average water at depth. Again, that's classic El Niño, and that will eventually be the demise of this El Niño as we move into the spring of year. All right, so, of course, what we really care about is how temperature differences in equatorial waters a thousand or more miles south of Hawaii impact the atmosphere, because that's how. how those temperature differences can influence our weather and climate at the monthly to seasonal scale. So, we have a couple of things to monitor that. Top graphic. is our outgoing long-wave radiation, which is a technical way to monitor where the big, giant tropical thunderstorms are and aren't. And that's important because that's how The winds coming off of those thunderstorms can affect the jet stream or the steering current, if you think of it that way, coming off of Asia and across the Pacific. So, with that background, the kind of the purple and red colors there in the top graphic show areas with more of the thunderstorm activity than average. The orange and brown colors show less, and This peak in this much enhanced thunderstorm activity east of the Dateline, but much less activity back over the west, across Indonesia, extending back across Malaysia. Again, classic. El Niño signature, as is the bottom graphic, which is really just the tool we use to monitor the strength. Of the, of the, Trade winds, and we see that trade winds are much weaker than normal across the, equatorial Pacific there, the little box area. is our bellwether area that we monitor to help quantify the El Niño or La Niña. Now, if you look there, you might wonder, well, looks like winds are kind of strong. Why do you say trade winds are much weaker than normal? Because they are much more westerly than normal. Of course, trade winds blow from east to the west, so if we've got more west wind, that means that, in general, that means that the trade winds are weaker than normal, although in some places, the actual wind, if you were standing On a ship right there, they would actually be out of the West, and that is quite unusual. But again, this is a classic signature for. For, an El Niño and particularly a strong El Niño. Alright, so now, we'll take a look at some of the tools that we have. for to construct the upcoming monthly and seasonal outlooks. We'll continue on the El Niño-La Niña vein, take a look at the expert evaluation, then look at, some statistical models, just using the past to get an idea of the future, and then the dynamic, seasonal climate models. They know about the physics, they know about a starting condition, but they know nothing about the past. And we'll look at the sea ice, sea surface temperatures, and of course, temperature and precipitation with some of those tools. Alright, so Starting off with El Niño in the expert's opinion. El Niño is a sure thing right into the early spring season of year. If you're a regular here, you know I like to do see how these forecasts evolve. In this case, we have September's outlook on the left-hand side, and the most recent issued last week on the right, and you can see there's not much change in this outlook, just being having any kind of El Niño near certainty till we get to the spring, but then the experts forecasting a fairly rapid decay, with neither El Niño or La Niña becoming the most likely category by the time we get to April, May, June. So, of course, since El Niño is certain, and is ongoing and certain, the big question is the strength. Again, September outlook on the left, and the most recent on the right. And you can see here, basically, the experts going with near certainty of a very strong El Niño. Super El Niño is not really a term used. But if you want to call very strong super, go for it, lots of people are. You can see that is forecast as either certain or very high probability right through the mid-winter season, through December, January, February, but then The intensity, the strength likely to weaken. Less than 50-50 chance we'll still be in that very strong. category by the time we get to the late winter, January, February, March, and then, again, you can see there that the chances of being in neither El Niño or La Niña increase pretty rapidly, and by the time we get to early summer. year. A small but not insignificant chance of La Niña reemerging. That would not be uncommon. We often see La Niñas follow on the heels of these very strong El Niños. Okay, statistical guidance, so Got 3 things here for you. Long-term trends, short-term trends, sometimes called optimum climate normals, and since we've got this strong El Niño, what do past El Niños have to tell us about the possible future? Okay, 50-year trends, temperatures on the left, precipitation on the right, these are for November. And, of course, as is usually the case, with temperatures, you can see the strongest trends over the last 50 years are on the North Slope, but down into the Northwest Arctic. This is no mystery why here, this is directly tied to sea ice loss. You can see south of the Brooks Range and east of, kind of, the Chukchi coast there, changes are still significant, especially across the northern half of the state, across portions of South Central, Copper River Basin down. Into at least portions of northern southeast, there is not much trend. Similarly, south of Norton Sound, there has been an increase in the last 50 years, but it's not very strong there. Precipitation on the right-hand side, not a lot of trend here around most of the state for November precipitation. Remember, precipitation, rain plus the water equivalent of snow. The one exception, of course, is up on the North Slope. With this significant trend in, across almost all the area for more November precipitation, that's of course directly related to the increase in temperatures and which all, both of which related to the Over the 50 years, decrease in sea ice, so you've got more water exposed to the atmosphere, during the month, especially in the Chukchi Sea, to supply moisture for precipitation. Alright, so that was the long term. How about the short term? So We're going to compare what happened in the 15 years, 2011 to 2025, to our 30-year baseline normal, which is 1991 to 2020. So, over the last 15 years, using the Alaska climate divisions here, there's 13 of them. I simply ask, how has the average in the last 15 years compared to our baseline period? And each climate division gets colored if the average over the last 15 years falls into the significantly above or significantly below normal category. So, with that background, November temperatures, you can see there, none of the 13 climate divisions, has the average been in that significantly below or significantly above category. For the November through January season temperatures, that's on the upper right, both the North Slope and the Aleutians, the average over the last 15 years has been in the significantly above normal category of the 1991 to 2020 baseline. Similarly, with precipitation, bottom left, November precipitation, north slope, last 15 years have fallen into the significantly above normal category. Southern Southeast, though, falling into the significantly below normal category. For the, November through January precipitation over the last 15 years, you can see the north slope, and now the eastern, interior climate divisions have fallen into the significantly above normal, but none of the 13 climate divisions, falling into the significantly below normal category over the last 15 years. Alright, so we've got this very strong El Niño. So if you're with us every month, this is a little bit different. Given the strength of this El Niño, I have I am only now using the strong and very strong El Niños to construct these analogs, so we have 8. strong and very strong El Niño since 1960, and so this is the composites for those 8 years. And again, we're doing, categories here. Each, season here. The what actually happened is compared to the 30-year baseline that would have been in use at the time. So, the 1972, 73, Season here is compared to the nor to the baseline normals of 1941 to 70, on up to 2015-16, where we compare what happened against the 1981 to 2010 baseline period, which would have been the appropriate season for that El Niño. So, that background, you can see November through January temperatures on the left-hand side, so if you've got a color there, that means that at least 5 of the 8 El Niños, strong or very strong El Niños, fell into the significantly above normal category, and, if it falls into the blue, 5, at least 5 of 8 fell into the significantly Below normal category. There's no blue anywhere in Alaska except for the, a few of the, Aleutian Islands there. Obviously, all of Southeast into the Southeast interior, including the Kenai Peninsula, Kodiak Island, and down the Alaska Peninsula. More than half fall into the significantly above normal. category. Remember, there's 3 categories here, so it's not just 50-50. As well as the, across the. basically northern Bering Sea into the Chukchi. Remember, this is the total integrated effect, so it's not because of the big changes in sea ice that northwest area may or may not have anything to do with El Niño. Precipitation on the right-hand side, as always, much more scattered, an area of at least 5 of the 8. have been significantly wetter than normal around Prince William Sound, though. Maybe some dry signal there across portions of the North Slope and Brooks Range, but all in all, this is a much messier picture than we see with temperatures. All right, and now, the dynamic climate models. So, here's what we'll look at here. The experimental sea ice forecast from the Climate Prediction Center. We've got, also got tools from the World Climate Service and the North American Multi-Model Ensemble that's put together. Assembled, I should say, by the Climate Prediction Center, and we'll look at sea surface temperatures, sea ice, and temperatures in precip. All right, so starting with sea surface temperatures, 4. the November through January, early winter season here. Forecast from the North American Multi-Model Ensemble, about 100 different, ensemble members going into this from 6 different forecast systems, and importantly, the forecasts from each model run are compared to its own system's climatology, not the real world, so that helps a little bit with bias correction. And you can see here, sea surface temperatures in aggregate here, forecast to continue above normal from Japan east all the way to the North American coast. There is an area, though. kind of offshore California, back towards, but not to Hawaii, where the 100-member average is actually in the Near normal category. The El Niño signal there is literally, in this case, off the scale, extending from south of Hawaii all the way to the South American coast. We, of course, naturally want to ask how good these forecasts are, and that's the skill on the right-hand side. When we're looking at ocean temperatures, we really want to see skill scores there in the purple colors. We have less of those purple colors in the North Pacific than we do in some seasons, so for forecasts made In October for the upcoming November through January period. We do have those blue those purple colors near Alaska back into the Bering Sea, but off of Japan and eastward, there's definitely more of those greens, which is much less skill than we would like to see. For ocean temperatures. Along the equator, though, the climate models do very well with the equatorial temperatures, which is important for El Niño, La Niña, and especially this year, we are watching that close. Alright, turning to sea ice This is an experimental product run by the Climate Prediction Center. It's an ensemble system. There's 20 different runs, so we started a little bit different initial conditions and run the model out. This goes out about. 8 months, and so one of the products that, comes out of this and CPC makes available, and my favorite product is, when do we get the first ice? And in the fall and winter, and then in the spring and summer, when do we get the first open water? And so that's what this graphic is highlighting. I've chunked up the data. into half-month intervals here, and then labeled some of them just to make it a little easier to read. If you were with us last month, you may remember that this model had a later freeze-up in the Chukchi and Northern Bering Sea than this model run does. I think that's catching on to the fact that there's much more ice farther south now than there had been. This forecast was made in late September, but that trend was already obvious. One thing to point out, you see the ice does get, in this model, it always gets down to the Pribilofs, and I think this is a function of the way these statistics are generated. Even if most models don't get ice, say, as far as the Pribilofs. What we're getting here is the average of the ones that do. So that, I think, is a little misleading. This product is probably best, for. For areas in the open ocean that are very likely or certain to have ice at some point in the season. So, November of. 2026, the forecast from the North American Multi-Model Ensemble. The way I like to look at these is how the forecast has evolved, and this is the this is the, calibrated probabilistic forecast. So. It's, probabilistic, and we're getting the chances of the favored category here, again, compared to the each individual each individual, ensemble system's climatology, and then comparing it to the real world, at the end, helps, is that calibrated part. Again, what we're looking at here are the category forecasts, not the actual departures. So How has the forecast for November changed through time? August forecasts for November are on the left hand side, forecasts that were made in September in the middle and the most recent on the right. So, just casting your eye across Alaska for temperature on top. Not a lot of change, really, over most of mainland Alaska. There's only there's either nothing, so equal chances of all three categories, or maybe a weak tilt to above normal, but it's pretty weak, except for southeast, where it's been pretty consistent. For, significantly above normal. Precipitation on the bottom, as is almost always the case. Not always, but almost always. There's not much signal there, no coherent areas, in the same places or same general area. Over most of Alaska, maybe if you. If you're really looking for something, maybe Bristol Bay, Alaska Peninsula, slightly favoring below normal totals for November, both back in August and the most recent forecast, but that was mostly gone. In September, so not a lot of agreement there. Now, also November forecast, this time from our colleagues at the World Climate Service. So what the World Climate Service does is they take a couple of different models, the US climate forecast system and the European system. And they put them together, but one step that the World Climate Service does that isn't done with the North American Multi-Model Ensemble is they give higher weight to the model that has Historically been better at this particular forecast season. So in this case, the model that's done better. for November forecasts that were made in October gets a higher weight. So here, a little bit different story than we saw in the NMME. You can see Most of mainland Alaska here favored in the significantly above normal category for November temperatures. Remember, it was mostly either equal chances of all three, or maybe very weak. tilt in the North American Multi-Model ensemble. Precipitation on the right, pretty much similar story. There's not a lot to go on here over for Alaska. Now, turning to the early winter season. from the NMME. Temperatures on top, precipitation on the bottom. Again, August forecast for November, December, January are on the left. Forecasts made in September are in the middle, and the most recent are on the right. Temperatures again, pretty similar pattern. Strongest chances for above normal in aggregate here from the NMME and southeast into the eastern mainland. But notice the last these three forecasts here, three most recent for November, December, January, do not have that warm tilt extending all the way back. to, western Alaska, do get it into, Kodiak Island, and maybe into Bristol Bay, but, not really, not really anything back, say, right on most of the Bering Sea coast, and not really much on the North Slope as well. Precipitation on the bottom. Again, if you're looking for some, maybe we can say that there's continuity there across the Alaska Peninsula, eastern Aleutians. For below normal precipitation, maybe in northwest Alaska, but didn't really see that back in the August forecast. But all in all, pretty weak, and compare that to the, to the continuity of that above-normal tilt, say, from California over to Florida, where the models are pretty consistent here for November through January. All right, World Climate Service early winter outlook. So, looks pretty looks pretty, similar overall to the North American Multi-Model ensemble, even with that skill weighting. We do not see that warm tilt extending back to western Alaska. Even a little bit of cool tilt now across the. across the Aleutians. The big difference, though, here is the precipitation on the right-hand side. You can see that swath of favoring significantly below normal. totals extending from north of the Gulf of Alaska coast across, say, the. Alaska Range and at least the central and southern interior, and then westward across the Seward Peninsula, all of southwest Alaska and the eastern Aleutians. Also see a little bit of that dry tilt into at least portions of southeast Alaska. And the last tool that we have, of course, is what the experts thought last month. This was the outlook for the early winter season that was issued in September. You can see, not dissimilar to some of the models we've been looking at, strongest chance for above normal temperatures, that's on the left, across southeast, and then for. For, western and southwest Alaska, equal chances. Precipitation, last month, the experts went with a slightly increased chances of above-normal precipitation, kind of the eastern Gulf Coast from about maybe Cordova over to, outer, northern southeast. And a below normal tilt there across portions of the western interior down into southwest Alaska. Fair chunk of the state though, no tilt, equal chances of all three categories. And the answer for that was released just yesterday morning. Ta-da! All right, CPC November outlook here. Generally, kind of followed the previous, seasonal outlook. We've got the tilt to favor significantly above normal across Southeast, extending into the eastern portion of the mainland, including Anchorage and Fairbanks area. A large swath of equal chances, so none of the three categories favored, except for out over the West Coast, CPC was convinced enough that they went for the rare increased chances of near normal. Now, because that near normal category is a pretty It's a pretty, narrow window. We don't often see this, but CPC went for it, this time. So, from about. the Seward Peninsula on south to about the Y-K Delta area, a slightly increased chance of near normal for November. Precipitation, the vast majority of the state has no tilt in the odds, none of the categories are favored. A little bit of lean towards above normal across portions of the North Slope there, and below normal for Kodiak Island and portions of the Bristol Bay and Alaska Peninsula area. Okay, turning to the early winter season now, we have a fairly strong tilt to favor significantly above normal across, southeast Alaska. No surprise there, that's what's, that has been the rule in past strong and very strong El Niños, and supported by pretty much all the models, and that, then the gradation as we moved west. to equal chances for all three categories. Across western, Alaska into, you know, kind of the western interior and western north and central North Slope as well. Precipitation, this month, we have lost the, any area with enhanced chances for significantly above normal precipitation, but a larger area with leaning towards significantly below normal. This is a pretty unusual forecast for Alaska. strong El Niño, so is one case where we, where we will see these large areas of significantly below normal in the, seasonal forecast. And, looking ahead to the midwinter season. Basically, evolution from the early winter season, the area with at least a slight tilt to significantly above normal has worked its way west, but not to the west coast. That's pretty much what we saw in the guidance. Still a very strong chance for, from a forecast perspective, for significantly above normal across southeast Alaska, but now extending into the northern Gulf Coast and even into the southeast interior. Much larger area with a significant chance of, in that significantly below normal category precipitation, and a very strong tilt there to favor below normal for portions of western and northwest Alaska. On the other hand, much of Alaska south of the Alaska Range and all of the southeast and Alaska Peninsula, south central Kodiak Island area. No tilt in the odds for any of the three categories. That is what I have for you this month. Got several interesting webinars coming up. This will be an interesting one, the ecology of mountain goats and avalanches in Alaska. That will be that will be a good one. And then, on November 20th, I'll be right back with you with the, with the November outlook. So Looks like we've got 3 minutes for questions and comments. Laura Weingartner Thanks, Rick. I am going to unmute everybody, but we have a question in the chat that I'll read. Let's see. What large-scale circulation processes cause the warm surface water plume during El Niño to dissipate rapidly, allowing colder La Niña conditions to emerge in the Niño 3.4 region? Does the warm water primarily sink through convection, or is it transported away and replaced by cooler water from the Niño 4 region? Rick Thoman Okay, as always, Rob, great question. Two primary mechanisms. One, that colder-than-normal water subsurface in the western Pacific will start to shoal eastward. And that's a sign of the impending decay. Eventually, that, of course, will surface. And another important, another important contributor is that, evaporative cooling from the, from the really warm waters there. in the central and eastern Pacific also, will start to enhance, the cooling once that reserve of warm water at depth. take is gets eroded away from the bottom, that, evaporative cooling starts to become, more effective. So those are two primary mechanisms of how things why the why the, El Niño is often very rapidly dissipates. That's that rapidness, though, is really driven by what's happening underneath the surface. Laura Weingartner If there's any more questions, you can either ask them yourself or throw them in the chat. have probably time for one more. All right, well, thanks everyone for coming, and thank you, Rick, for taking the time to provide the monthly Alaska Climate Briefing. Everyone have a great weekend, and we'll see you month. Rick Thoman Thank you.