WEBVTT 00:00:00.000 --> 00:00:01.780 Welcome to Meteorology Matters. We've been keeping 00:00:01.780 --> 00:00:05.599 a close eye on tropical cyclone Errol out there 00:00:05.599 --> 00:00:09.140 in the Indian Ocean near Australia. And it's 00:00:09.140 --> 00:00:11.320 been quite something to watch. This storm really 00:00:11.320 --> 00:00:13.619 intensified quickly. It really did. Yeah. Errol 00:00:13.619 --> 00:00:16.899 got going Tuesday night. And by Wednesday morning, 00:00:17.179 --> 00:00:19.660 Australian Western Time, it was already a category 00:00:19.660 --> 00:00:23.239 two cyclone on their scale, sitting about 515 00:00:23.239 --> 00:00:27.280 kilometers northwest of Broome. And it was heading 00:00:27.280 --> 00:00:29.480 west at that point. And just to give folks a 00:00:29.480 --> 00:00:31.839 sense of the power here, the Joint Typhoon Warning 00:00:31.839 --> 00:00:33.799 Center, that's the collaboration between the 00:00:33.799 --> 00:00:37.359 U .S. Navy and NOAA, the National Oceanic and 00:00:37.359 --> 00:00:39.719 Atmospheric Administration, they reported early 00:00:39.719 --> 00:00:42.359 Thursday, local time, that Errol hit sustained 00:00:42.359 --> 00:00:46.060 winds of 144 miles per hour. Wow. Yeah, that's 00:00:46.060 --> 00:00:47.859 significant. I mean, put that in Atlantic terms, 00:00:47.939 --> 00:00:49.759 that's a category four hurricane on the Saffir 00:00:49.759 --> 00:00:52.439 -Simpson scale. A major hurricane. So what exactly 00:00:52.439 --> 00:00:54.640 was going on? What conditions allowed it to, 00:00:54.640 --> 00:00:56.659 you know, ramp up like that? Well, a couple of 00:00:56.659 --> 00:00:59.240 really key factors lined up perfectly. First 00:00:59.240 --> 00:01:01.679 off, the ocean was incredibly warm there. Sea 00:01:01.679 --> 00:01:03.579 surface temperatures were hovering around 30 00:01:03.579 --> 00:01:06.159 degrees Celsius. 30 degrees? That's quite warm. 00:01:06.239 --> 00:01:08.620 Oh, yeah. The minimum threshold you generally 00:01:08.620 --> 00:01:12.530 need is about 26 .5 C, so it had... plenty of 00:01:12.530 --> 00:01:15.450 fuel basically, like high octane fuel for the 00:01:15.450 --> 00:01:17.569 storm's engine. Makes sense. Were there other 00:01:17.569 --> 00:01:19.530 things happening in the atmosphere? Absolutely. 00:01:19.909 --> 00:01:23.290 We also saw really good outflow aloft. So think 00:01:23.290 --> 00:01:26.930 of it like a chimney. The storm could vent easily 00:01:26.930 --> 00:01:31.090 up top, which helps it draw in more warm, moist 00:01:31.090 --> 00:01:33.650 air near the surface. It just keeps that engine 00:01:33.650 --> 00:01:36.829 running efficiently. OK. And I remember seeing 00:01:36.829 --> 00:01:39.689 something about the storm's size. potentially 00:01:39.689 --> 00:01:41.909 playing a role, is that right? That's an interesting 00:01:41.909 --> 00:01:45.549 aspect, yeah. Sometimes these relatively smaller 00:01:45.549 --> 00:01:47.750 tropical cyclones, when they hit those perfect 00:01:47.750 --> 00:01:50.650 conditions, they can spin up remarkably fast. 00:01:51.069 --> 00:01:52.769 It's almost like all that energy gets focused 00:01:52.769 --> 00:01:56.049 into a tighter area, allowing for quicker intensification. 00:01:56.310 --> 00:01:57.829 And looking at the satellite imagery, it seemed 00:01:57.829 --> 00:01:59.790 like it got organized pretty quickly, too. It 00:01:59.790 --> 00:02:02.670 did. By Wednesday morning, it looked very well 00:02:02.670 --> 00:02:05.849 -defined. Seeing that clear symmetrical eye develop, 00:02:05.909 --> 00:02:08.289 that's often a sign of a really strong storm. 00:02:08.360 --> 00:02:11.120 that isn't facing much resistance like wind shear. 00:02:11.439 --> 00:02:13.560 The Joint Typhoon Warning Center actually called 00:02:13.560 --> 00:02:15.860 it an impressive look on the infrared satellite 00:02:15.860 --> 00:02:20.259 pictures. They noted an eye about eight nautical 00:02:20.259 --> 00:02:22.479 miles wide. And this is wild. They measured the 00:02:22.479 --> 00:02:25.080 temperature inside the eye at positive 15 degrees 00:02:25.080 --> 00:02:28.340 Celsius. That sounds really warm for the core 00:02:28.340 --> 00:02:31.479 of a cyclone. What does that signify? It is quite 00:02:31.479 --> 00:02:34.340 warm, and it's generally a sign of a very intense 00:02:34.340 --> 00:02:37.639 system. That warmth comes from sinking air within 00:02:37.639 --> 00:02:40.819 the eye, which compresses and heats up. So a 00:02:40.819 --> 00:02:43.939 clear warm eye like that, surrounded by those 00:02:43.939 --> 00:02:46.659 intense thunderstorms in the eye wall, that's 00:02:46.659 --> 00:02:49.560 classic strong cyclone structure. And Errol, 00:02:49.680 --> 00:02:51.740 I mean... It went through what was described 00:02:51.740 --> 00:02:55.419 as an amazing period of extreme rapid intensification. 00:02:55.599 --> 00:02:57.900 Amazing period, wow. Yeah, the winds increased 00:02:57.900 --> 00:03:01.560 by 85 knots in just 24 hours. 85 knots. In a 00:03:01.560 --> 00:03:04.740 day. In a day. And over 50 knots in just 12 hours, 00:03:04.800 --> 00:03:07.259 those are just huge jumps in strength. That's 00:03:07.259 --> 00:03:09.240 unbelievable. And some microwave satellite passes 00:03:09.240 --> 00:03:11.300 suggested it might have undergone a quick eyewall 00:03:11.300 --> 00:03:13.780 replacement cycle, too. Ah, explain that a bit. 00:03:14.060 --> 00:03:16.389 What's an eyewall replacement cycle? So basically, 00:03:16.409 --> 00:03:18.930 think of the original eye wall, that ring of 00:03:18.930 --> 00:03:21.889 intense storms as the main engine. Sometimes 00:03:21.889 --> 00:03:24.050 a new larger ring of thunderstorms starts to 00:03:24.050 --> 00:03:27.210 form outside of it. Eventually, this outer ring 00:03:27.210 --> 00:03:29.389 can strengthen, contract, and kind of choke off 00:03:29.389 --> 00:03:31.629 the inner eye wall, replacing it. It can cause 00:03:31.629 --> 00:03:33.770 a little dip in intensity sometimes, but often 00:03:33.770 --> 00:03:35.770 the storm comes out stronger afterwards with 00:03:35.770 --> 00:03:38.150 a larger eye. Right, like getting a bigger engine. 00:03:38.270 --> 00:03:41.770 So at its absolute peak, what were the wind speeds 00:03:41.770 --> 00:03:44.159 we were looking at? Well, the Joint Typhoon Warning 00:03:44.159 --> 00:03:46.879 Center's initial assessment put the peak intensity 00:03:46.879 --> 00:03:50.219 around 140 knots. That translates to roughly 00:03:50.219 --> 00:03:53.979 161 miles per hour. Wow. And the Australian Bureau 00:03:53.979 --> 00:03:56.919 of Meteorology, the BOM, they use a 10 -minute 00:03:56.919 --> 00:03:59.979 average for sustained winds. They reported maximum 00:03:59.979 --> 00:04:03.719 10 -minute winds of 100 knots, which is 185 kilometers 00:04:03.719 --> 00:04:06.080 per hour. Okay. But they also noted three -second 00:04:06.080 --> 00:04:09.580 gusts hitting 140 knots, or 260 kilometers per 00:04:09.580 --> 00:04:13.250 hour, around 1800 UTC on April— 16th. So based 00:04:13.250 --> 00:04:15.490 on their scale, that made Errol a severe travel 00:04:15.490 --> 00:04:17.430 cyclone. Which is their equivalent of Cat 4. 00:04:17.649 --> 00:04:19.829 Exactly. Equivalent to a category 4 on the Saffir 00:04:19.829 --> 00:04:21.930 -Simpson scale we use for hurricanes. A very 00:04:21.930 --> 00:04:24.350 potent storm. Okay, so you have this beast of 00:04:24.350 --> 00:04:27.170 a storm. What was the thinking on where it was 00:04:27.170 --> 00:04:29.069 going next? Was it just going to keep heading 00:04:29.069 --> 00:04:33.420 west? Uh, no, actually. The forecast models are 00:04:33.420 --> 00:04:35.839 pretty consistent in showing it making a distinct 00:04:35.839 --> 00:04:38.560 left turn, sort of hooking back towards Western 00:04:38.560 --> 00:04:41.420 Australia's Kimberley Coast. That turn was expected 00:04:41.420 --> 00:04:43.740 around Thursday. And I guess making that turn 00:04:43.740 --> 00:04:45.740 would change the environment around the storm. 00:04:46.300 --> 00:04:49.100 Precisely. As it was forecast to make that turn, 00:04:49.240 --> 00:04:52.490 the conditions ahead looked less... Well, less 00:04:52.490 --> 00:04:54.689 ideal for it to stay that strong. Less favorable, 00:04:55.050 --> 00:04:57.209 yeah. What kind of conditions? Mainly increasing 00:04:57.209 --> 00:05:00.009 vertical wind shear. You know, winds blowing 00:05:00.009 --> 00:05:02.430 at different speeds or directions, at different 00:05:02.430 --> 00:05:04.089 heights in the atmosphere. Right, that can tear 00:05:04.089 --> 00:05:05.810 a storm apart. It can disrupt the structure, 00:05:05.889 --> 00:05:09.110 yeah. And also, an intrusion of drier air was 00:05:09.110 --> 00:05:10.810 expected to get pulled into the circulation. 00:05:11.389 --> 00:05:13.689 Storms like this need that moist air to survive, 00:05:13.810 --> 00:05:16.529 so dry air is like poison to them. Okay, so the 00:05:16.529 --> 00:05:18.949 forecast was for weakening as it got closer to 00:05:18.949 --> 00:05:22.120 Australia. That was the consensus, yes. Most 00:05:22.120 --> 00:05:24.759 forecasts had it weakening, potentially dropping 00:05:24.759 --> 00:05:27.379 below tropical cyclone strength before it actually 00:05:27.379 --> 00:05:30.899 made landfall. So coming ashore as a tropical 00:05:30.899 --> 00:05:33.259 low sometime over the weekend. And the Joint 00:05:33.259 --> 00:05:35.860 Typhoon Warning Center agreed with that weakening 00:05:35.860 --> 00:05:38.959 friend. They did. They also pointed to the increasing 00:05:38.959 --> 00:05:41.860 sheer and dry air, suggesting it could weaken 00:05:41.860 --> 00:05:44.459 to tropical storm strength within about 48 hours 00:05:44.459 --> 00:05:48.060 and then dissipate over land. How about the Australian 00:05:48.060 --> 00:05:51.529 Bureau of Meteorology, the BOM? Similar outlook. 00:05:52.050 --> 00:05:54.569 Very similar. They also expected it to weaken 00:05:54.569 --> 00:05:57.069 as it neared the West Kimberley coast, likely 00:05:57.069 --> 00:05:59.589 falling below cyclone intensity before crossing 00:05:59.589 --> 00:06:02.329 the coast. Their specific forecast mentioned 00:06:02.329 --> 00:06:05.569 landfall as a tropical low, maybe near Cape Lavec 00:06:05.569 --> 00:06:08.329 or Kakatu Island on Saturday morning. Now, it's 00:06:08.329 --> 00:06:10.670 important to remember, even if it weakens to 00:06:10.670 --> 00:06:12.689 a tropical low, that doesn't mean the danger 00:06:12.689 --> 00:06:15.519 is over. Absolutely not. That's a crucial point. 00:06:15.899 --> 00:06:18.379 Even a weakening system, or its remnants, can 00:06:18.379 --> 00:06:21.360 still bring really significant impacts, especially 00:06:21.360 --> 00:06:23.779 heady rainfall. So what were the main concerns 00:06:23.779 --> 00:06:26.100 for the Kimberley region? The remnants of Errol 00:06:26.100 --> 00:06:28.339 were expected to deliver a pretty good burst 00:06:28.339 --> 00:06:30.740 of heady rain across parts of the Kimberley, 00:06:30.879 --> 00:06:33.279 starting Friday and going into the weekend. And 00:06:33.279 --> 00:06:35.720 that rain could spread quite far inland, too. 00:06:35.920 --> 00:06:39.420 And winds. Still concern. even below cyclone 00:06:39.420 --> 00:06:41.500 strength. Yes. There was still a possibility 00:06:41.500 --> 00:06:44.759 of gale force damaging winds, particularly for 00:06:44.759 --> 00:06:47.319 the coastal stretch between Kakatu Island and 00:06:47.319 --> 00:06:50.660 Beagle Bay from Friday into Saturday morning. 00:06:50.759 --> 00:06:53.699 OK. And depending on the exact track it took 00:06:53.699 --> 00:06:56.459 as it weakened, those stronger winds might have 00:06:56.459 --> 00:06:59.100 extended south towards Broome as well. So heavy 00:06:59.100 --> 00:07:02.740 rain. potential for damaging winds. Any specific 00:07:02.740 --> 00:07:05.199 areas highlighted for the heaviest rain. Yeah, 00:07:05.199 --> 00:07:07.740 they mentioned isolated heavy falls possible 00:07:07.740 --> 00:07:10.079 between Curie Bay and Broome, especially overnight 00:07:10.079 --> 00:07:12.180 Friday into Saturday morning. And it's always 00:07:12.180 --> 00:07:14.600 worth stressing flash flooding is a major risk 00:07:14.600 --> 00:07:17.100 with these systems, even while inland far from 00:07:17.100 --> 00:07:20.199 the center. You don't need hurricane winds for 00:07:20.199 --> 00:07:23.339 dangerous flooding rainfall. Good reminder. It's 00:07:23.339 --> 00:07:25.060 interesting thinking about these southern hemisphere 00:07:25.060 --> 00:07:27.920 cyclones compared to Atlantic hurricanes. Are 00:07:27.920 --> 00:07:30.129 there big differences besides just the name and 00:07:30.129 --> 00:07:33.670 location? That's a good question. Statistically, 00:07:33.889 --> 00:07:36.230 they're less common. Only about a quarter of 00:07:36.230 --> 00:07:38.610 the planet's tropical cyclones form in the southern 00:07:38.610 --> 00:07:41.430 hemisphere. Oh, only a quarter. Yeah. But strength 00:07:41.430 --> 00:07:44.589 -wise, once they reach sustained winds of 74 00:07:44.589 --> 00:07:47.089 miles per hour or more, they're essentially the 00:07:47.089 --> 00:07:49.129 same phenomenon as a hurricane, just called a 00:07:49.129 --> 00:07:52.069 cyclone. So the potential impact is similar. 00:07:52.389 --> 00:07:55.410 What about how they behave? The most obvious 00:07:55.410 --> 00:07:57.689 difference is the spin direction. Because of 00:07:57.689 --> 00:08:00.149 the Coriolis effect on a rotating Earth, cyclones 00:08:00.149 --> 00:08:03.089 down there spin clockwise. Right. Opposite to 00:08:03.089 --> 00:08:05.449 our counterclockwise hurricanes. Exactly. It's 00:08:05.449 --> 00:08:08.329 a mirror image. And where do these cyclones typically 00:08:08.329 --> 00:08:10.529 hit in the Southern Hemisphere? They can impact 00:08:10.529 --> 00:08:13.550 Eastern Africa, Madagascar gets hit quite often, 00:08:13.629 --> 00:08:15.689 and then of course the western, northern, and 00:08:15.689 --> 00:08:18.709 eastern coasts of Australia, plus many of the 00:08:18.709 --> 00:08:21.319 island nations nearby. And their season is different 00:08:21.319 --> 00:08:24.180 too, right? Yep, opposite to ours. Their main 00:08:24.180 --> 00:08:27.259 tropical cyclone season runs generally from late 00:08:27.259 --> 00:08:30.720 October through to May. OK. With the peak activity 00:08:30.720 --> 00:08:32.919 for the Australian region usually falling in 00:08:32.919 --> 00:08:35.639 late February or early March. You mentioned Errol 00:08:35.639 --> 00:08:38.899 was the 11th named storm in the Australian region 00:08:38.899 --> 00:08:41.259 this season. Is that a lot? It actually is, yeah. 00:08:41.399 --> 00:08:43.759 It makes this the most active season they've 00:08:43.759 --> 00:08:46.580 had in six years. Wow, since 2019. That's right. 00:08:46.740 --> 00:08:48.700 When forecasters are tracking these things, trying 00:08:48.700 --> 00:08:51.100 to figure out intensity and path, where does 00:08:51.100 --> 00:08:53.279 all the information come from? Seems like a massive 00:08:53.279 --> 00:08:56.059 undertaking. It really is. The tracking data 00:08:56.059 --> 00:08:59.639 comes from multiple centers, including NOAA, 00:09:00.019 --> 00:09:02.460 the National Oceanic and Atmospheric Administration, 00:09:03.059 --> 00:09:05.220 and the Joint Typhoon Warning Center we mentioned 00:09:05.220 --> 00:09:08.299 earlier. Satellite imagery is absolutely crucial. 00:09:08.600 --> 00:09:10.940 That comes from NOAA as well, and also the Japanese 00:09:10.940 --> 00:09:13.919 Meteorological Agency, JMA. They have excellent 00:09:13.919 --> 00:09:16.080 satellite coverage over that region. And rainfall 00:09:16.080 --> 00:09:20.100 forecasts. Those also heavily rely on data and 00:09:20.100 --> 00:09:22.399 models run by NOAA. It's a huge international 00:09:22.399 --> 00:09:24.820 effort, really. Sounds like it. Yeah. You mentioned 00:09:24.820 --> 00:09:27.399 the models earlier showed Errol turning. Was 00:09:27.399 --> 00:09:29.360 there good agreement on where exactly it would 00:09:29.360 --> 00:09:32.519 end up? You know, initially. On the westward 00:09:32.519 --> 00:09:34.820 track in the turn, there was pretty good agreement 00:09:34.820 --> 00:09:37.659 among the different computer models. But as the 00:09:37.659 --> 00:09:39.860 forecast went further out in time, looking towards 00:09:39.860 --> 00:09:42.679 landfall, there started to be a bit more spread, 00:09:42.860 --> 00:09:44.879 a bit more divergence in the models about the 00:09:44.879 --> 00:09:47.159 exact location and timing. Which just shows how 00:09:47.159 --> 00:09:49.059 tricky forecasting these things can be, right? 00:09:49.279 --> 00:09:51.379 Absolutely. It really highlights the complexity. 00:09:51.600 --> 00:09:54.759 Predicting the precise path days in advance is 00:09:54.759 --> 00:09:56.980 still one of the biggest challenges in meteorology. 00:09:57.559 --> 00:10:00.580 So just to recap then, tropical cyclone Errol. 00:10:01.399 --> 00:10:03.279 intensified incredibly rapidly in the Indian 00:10:03.279 --> 00:10:06.399 Ocean, became a very powerful system equivalent 00:10:06.399 --> 00:10:09.620 to a category four hurricane. Yep. Then it was 00:10:09.620 --> 00:10:11.500 forecast to turn towards the Kimberley coast 00:10:11.500 --> 00:10:14.580 of Western Australia, expected to weaken significantly 00:10:14.580 --> 00:10:17.779 before hitting land likely as a tropical low. 00:10:17.940 --> 00:10:20.120 That's the gist of it. But even as a weaker system, 00:10:20.409 --> 00:10:23.730 it still pose a real threat of heavy rain and 00:10:23.730 --> 00:10:25.929 potentially damaging winds to that region. Correct. 00:10:26.350 --> 00:10:28.610 And the key message for anyone potentially affected 00:10:28.610 --> 00:10:31.629 is always to stay tuned to the latest official 00:10:31.629 --> 00:10:33.850 warnings and forecasts from the Australian Bureau 00:10:33.850 --> 00:10:36.590 of Meteorology, the BOM. They'll have the most 00:10:36.590 --> 00:10:39.470 current information. Definitely. You know, looking 00:10:39.470 --> 00:10:42.110 at a storm like Errol, it just makes you appreciate 00:10:42.110 --> 00:10:44.830 the sheer complexity involved in forecasting 00:10:44.830 --> 00:10:47.889 these powerful weather events. So many factors 00:10:47.889 --> 00:10:50.470 in the ocean and atmosphere, all interacting. 00:10:50.850 --> 00:10:52.970 It's true. It underscores the constant effort 00:10:52.970 --> 00:10:55.070 and the advancements being made in meteorology 00:10:55.070 --> 00:10:57.649 to better understand and predict these phenomena. 00:10:58.090 --> 00:11:00.429 Every storm teaches us something new. Absolutely. 00:11:00.889 --> 00:11:02.669 Well, for listeners wanting more meteorological 00:11:02.669 --> 00:11:05.370 insights and updates, definitely follow meteorologist 00:11:05.370 --> 00:11:07.710 Rob Jones. You can find him on Instagram. His 00:11:07.710 --> 00:11:10.230 handle is just Meteorologist. Easy to remember. 00:11:10.389 --> 00:11:14.110 Yeah. And on TikTok, he's TV Meteorologist. Plus 00:11:14.110 --> 00:11:16.330 check out his YouTube channel. Search for Rob 00:11:16.330 --> 00:11:18.269 Jones Hurricane. That's also where you can find 00:11:18.269 --> 00:11:20.830 the playlist for this podcast, Meteorology Matters. 00:11:20.990 --> 00:11:22.190 Great resources to check out.