00:00We're going to take you into the tropics with a forecast feed as Hawaii is bracing
00:04for some tropical impacts coming up this weekend as there's going to be, again, a strengthening
00:10tropical system that approaches the islands, and it will be a situation with some heavy
00:15rain and some wind in, especially the Big Island, but some of the central Hawaiian islands
00:19as well.
00:20I wanted to kind of pull out, look at a little bit of context here for Hawaii before we get
00:24into some details with our forecast and looking at history.
00:28I know that Hawaii often isn't front and center in the hurricane conversation, as we often
00:33are drawn to the east coast, and a lot of the Pacific action, at least for the eastern and
00:39central Pacific, often tends to miss land.
00:41We have some Mexican impacts sometimes.
00:43Sometimes we get these secondary impacts in the desert southwest, southern California,
00:46after Mexican landfalls.
00:48Many storms approach Hawaii and weaken as they approach, but there are exceptions, and in
00:53Niki, in 1992, that was an El Nino year, that was a huge, huge impact, a $3 billion storm.
01:01Today's dollars would be $6.7, maybe $6.8 billion.
01:05And 10 years earlier, we had, again, a high-impact storm with IWA.
01:10Lane and Esel in the past 15 years have also brought significant impacts to Hawaii.
01:17And a lot of the impacts are sometimes tied to wind and rain.
01:21The flooding is very, very dangerous and costly, though.
01:25You can see some of the more recent flood producers.
01:28Well, among the past 80 years or so, we've had some tremendous rainfall.
01:33Lane in 2018.
01:34I remember I was about a year into my time here at AccuWeather.
01:37That was just tremendous flooding that we saw there with Lane in 2018.
01:4158 inches of rain in one spot.
01:44And Hone, in 2024, brought more than two feet of rain.
01:48We have an AccuWeather local storm max of a couple feet of rain with this storm.
01:54One thing to consider, the east slopes of the Big Island see tremendous amounts of upslope.
02:01And some of these areas, just looking at the topography of Hawaii,
02:05we have areas that are prone to drought and dryness,
02:09and areas that are prone to significant rainfall.
02:12And when we talk about, well, we've had some of the downsloping winds
02:16that have led to serious fires.
02:19The Maui County wildfires, we may think of, just a couple of years ago.
02:23One thing, if we just draw a dashed line right through the center
02:28of the highest elevations of some of these islands,
02:31one thing to consider is if you have flow from the east,
02:35which is typically the case, you have very, very strong upslope
02:41on the east side of the mountains.
02:43And that's going to squeeze out tremendous amounts of rain.
02:47I'm going to change to just a regular telestrator instead of the arrow here.
02:51Tremendous amounts of rain on the east slopes of the mountains.
02:53And that squeezes out very, very heavy rain.
02:56Mount Waiali Ali, one of the wettest spots on Earth,
02:59gets hundreds of inches of rain a year because of this upslope
03:02on the east side of some of the mountains here in Hawaii.
03:06On the other hand, on the west side, we get dry downsloping wind
03:11that leads to far, far less rain.
03:14And when we get a tropical system, just like with the Kona Low,
03:18we're going to see an extremely high amount of rainfall
03:21that hammers the east slopes of the Big Island here.
03:25And the most likely impact zone is going to be the Big Island.
03:28We don't know for sure if there's going to be a true landfall or not.
03:31I know that Anna and I have been covering that.
03:34And our forecast team is working hard to bring you the latest.
03:37But again, a subtle jog north or south with the storm track
03:41over the weekend is going to bring big changes.
03:43Now, I want to zoom in.
03:45I'm going to zoom in on some impacts here in the computer modeling.
03:47But first off, just to show you, I know there are a lot of lines.
03:50We've got the wind barb and so forth.
03:52I'm circling Hawaii there.
03:54So you can just frame up your perspective here.
03:57And these areas of bright colors on the map,
04:01these are areas of spin or vorticity in the atmosphere.
04:04There's also a strong upper-level low-pressure system to the north.
04:07We've got an upper-level ridge off the west coast.
04:11And overall, we can begin to kind of fill in the dots here
04:14with the steering flow around these features.
04:17But you'll notice if you're around the belly.
04:19And this is a Bernie Rayno thing.
04:22He's been on vacation this week.
04:23But, you know, he teaches a lot of lessons when he does the weather.
04:26And we all learn a lot from him.
04:28Under the belly of a ridge.
04:29He often says that, talking about areas of favored tropical development.
04:32Well, here's a big ridge of high pressure under the south side of that.
04:35That's where you can often see a favorable zone for development.
04:39And that's what we're facing here, again, with this.
04:41So if we focus our eye on that clustering of bright colors
04:44down to the south of that ridge of high pressure,
04:47that is, again, the formative stages of this next tropical system.
04:51I don't want to commit to the name
04:53because there's another disturbance to the east
04:54that could steal the name of this one.
04:56But, again, so it has yet to be named.
04:59But we're going to be watching.
05:00As this focuses, it becomes more organized.
05:03And now it's moving Thursday night and Friday
05:05into an area near the Big Island.
05:06Now, this is the GFS forecast being steered by the movement
05:10of that upper-level ridge that may be shunting west a little bit.
05:16And, again, along with that, the circulation, the flow,
05:19steering circulations, the steering flow,
05:21influencing the storm to travel, as it will,
05:24into an area very close to the Big Island Saturday night.
05:28Saturday night.
05:29And then now the GFS actually pulls it north right across the islands,
05:32and it would rapidly have some weakening
05:34because of land interaction with those big mountains on the Big Island.
05:37And then Sunday afternoon it would be pulling west.
05:39Now, let's see what the European does.
05:41The European similarly focuses it.
05:42It trends a little farther south.
05:44Not by a lot, but if you take the European literally,
05:47as I'm showing this version to you,
05:49we might not even see a true landfall with that one.
05:51But it's going to be very close to the Big Island here
05:53around the same time frame.
05:55All right, let's look at some impacts.
05:56Here would be the rainfall picking up Saturday morning on the Big Island,
06:00increasing.
06:01Now, the GFS, remember, takes it farther north,
06:03right over the Big Islands.
06:04We see some significant weakening after land interaction.
06:07And with the European, a little farther south,
06:11that would keep the east slopes of the Big Island
06:14firmly in the upslope zone the whole time
06:17until it really moves far away to the west.
06:18And that would bring some tremendous rainfall to these areas.
06:20So how much rain are we looking at?
06:21Well, in the European, we'd be looking at about 8 inches on the summits
06:25and 6 to 8 there to the east.
06:28In the GFS, I think this is probably going to underperform.
06:31I think we'd see more rain than the resolution this model can actually handle.
06:35But that's the idea.
06:36And you can see gusts to 65 knots on the east shore of the Big Island in the GFS
06:41and gusts to 86 on the summit.
06:43That's in knots.
06:44So at about 10 to 15 miles per hour, about 10 miles per hour.
06:48So we're looking at strong, strong winds.
06:50Stay with us for more on this.
06:51And we're looking at strong, strong winds.
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