With hurricane season upon the northern Pacific and Atlantic oceans, I wanted to emphasize the MAIN key to determining hurricane strength:
LOW pressure = BAD hurricane
This idea is counterintuitive because we associate high pressure with stress and low pressure with pleasantness.
But for storms LOW pressure is BAD NEWS.
(This also explains the destructive force of tornados, whose spouts contain a low-pressure system.)
If you live in a hurricane-prone area, it's important to know this because weather forecasters tend to base hurricane warnings on windspeed.
Windspeed matters a lot.
But pressure matters MORE.
In fact, when Hurricane Ida stormed through the eastern half of the United States, many people were caught by surprise.
But the weather forecasters warned everyone of the impending storms from Ida.
Ultimately, journalists made comments about how too many warnings and too much hype cause people to feel jaded and apathetic.
They stop taking reports seriously.
That's true.
But why not simply make more accurate forecasts and adjust the warnings according to that better accuracy?
In other words:
If you do your own 1-minute research, you'll immediately see that, for example, while Ida was no longer classified as a hurricane (because Ida went so far inland, no ocean was involved), Ida's pressure remained unusually low — a low associated with a Category 1 hurricane or a Tropical Storm.
So it's basically like a Category 1 hurricane or Tropical Storm swept through the eastern United States...except no one was calling it that.
But that's what it was. And that's why Ida caused so much havoc.
It wasn't a regular landlocked rain storm.
It was more like a hurricane or tropical storm, but over land rather than ocean or sea.
LOW pressure = BAD hurricane
This idea is counterintuitive because we associate high pressure with stress and low pressure with pleasantness.
But for storms LOW pressure is BAD NEWS.
(This also explains the destructive force of tornados, whose spouts contain a low-pressure system.)
If you live in a hurricane-prone area, it's important to know this because weather forecasters tend to base hurricane warnings on windspeed.
Windspeed matters a lot.
But pressure matters MORE.
In fact, when Hurricane Ida stormed through the eastern half of the United States, many people were caught by surprise.
But the weather forecasters warned everyone of the impending storms from Ida.
Ultimately, journalists made comments about how too many warnings and too much hype cause people to feel jaded and apathetic.
They stop taking reports seriously.
That's true.
But why not simply make more accurate forecasts and adjust the warnings according to that better accuracy?
In other words:
If you do your own 1-minute research, you'll immediately see that, for example, while Ida was no longer classified as a hurricane (because Ida went so far inland, no ocean was involved), Ida's pressure remained unusually low — a low associated with a Category 1 hurricane or a Tropical Storm.
So it's basically like a Category 1 hurricane or Tropical Storm swept through the eastern United States...except no one was calling it that.
But that's what it was. And that's why Ida caused so much havoc.
It wasn't a regular landlocked rain storm.
It was more like a hurricane or tropical storm, but over land rather than ocean or sea.
Also Important: At What SPEED the Pressure DROPS
Storm pressure is measured in millibars, though it's also be measured in inches or centimeters.
If a storm's pressure drops by 6 millibars within 3 hours, that is a "rapidly intensifying" storm.
Many times, an oceanic storm system starts off at a higher pressure (above 1000 millibars).
Most oceanic storm systems read between 1001 millibars to 1008 millibars.
That's not hurricane intensity, although they are serious storms and you should stay away from the beach.
However, if a storm starts at 1008, then plunges to 1002 within a couple of hours, that demonstrates rapid intensification and indicates a hurricane on the way, even though 1002 isn't yet of hurricane-intensity.
If a storm's pressure drops by 6 millibars within 3 hours, that is a "rapidly intensifying" storm.
Many times, an oceanic storm system starts off at a higher pressure (above 1000 millibars).
Most oceanic storm systems read between 1001 millibars to 1008 millibars.
That's not hurricane intensity, although they are serious storms and you should stay away from the beach.
However, if a storm starts at 1008, then plunges to 1002 within a couple of hours, that demonstrates rapid intensification and indicates a hurricane on the way, even though 1002 isn't yet of hurricane-intensity.
How to Measure the Intensity of a Hurricane
Pressure is generally measured in millibars (mb).
Here's a chart of how they categorize hurricanes:
Here's a chart of how they categorize hurricanes:
Category 1: Minimal
Greater than 980 mb or 28.94 in; windspeed 119–153 km/h or 74–95 mph
Category 2: Moderate
965 to 979 mb or 28.50 to 28.91 in; windspeed 154–177 km/h or 96–110 mph
Category 3: Extensive
945 to 964 mb or 27.91 to 28.47 in; windspeed 178–208 km/h or 111–129 mph
Category 4: Extreme
920 to 944 mb or 27.17 to 27.88 in; windspeed 209–251 km/h or 130–156 mph
Category 5: Terrible
Less than 919 mb, 27.17 in.; windspeed more than 252 km/h or 157 mph
Greater than 980 mb or 28.94 in; windspeed 119–153 km/h or 74–95 mph
Category 2: Moderate
965 to 979 mb or 28.50 to 28.91 in; windspeed 154–177 km/h or 96–110 mph
Category 3: Extensive
945 to 964 mb or 27.91 to 28.47 in; windspeed 178–208 km/h or 111–129 mph
Category 4: Extreme
920 to 944 mb or 27.17 to 27.88 in; windspeed 209–251 km/h or 130–156 mph
Category 5: Terrible
Less than 919 mb, 27.17 in.; windspeed more than 252 km/h or 157 mph
So when Hurricane Ida was firmly over land in 2021, I was concerned to note how Ida remained so low-pressure, even far from the ocean.
If I remember correctly, Ida remained at 998 millibars over dry land, even though her windspeeds slowed down quite a lot.
But again: The PRESSURE determines the intensity — NOT the windspeed.
Yes, windspeed matters.
But windspeed is not the main factor; it is secondary to pressure.
So the weather forecasters were correct in their warnings, but people stopped taking them seriously because of all the warnings that didn't end up being nearly as bad as predicted.
Again, this happens because the news focuses on windspeed.
But you should look at PRESSURE.
How do you do that?
If I remember correctly, Ida remained at 998 millibars over dry land, even though her windspeeds slowed down quite a lot.
But again: The PRESSURE determines the intensity — NOT the windspeed.
Yes, windspeed matters.
But windspeed is not the main factor; it is secondary to pressure.
So the weather forecasters were correct in their warnings, but people stopped taking them seriously because of all the warnings that didn't end up being nearly as bad as predicted.
Again, this happens because the news focuses on windspeed.
But you should look at PRESSURE.
How do you do that?
How to Discover Storm Pressure within 1 Minute
You can call the NOAA. (I don't have their number.)
Or you can go here:
https://www.nhc.noaa.gov/
A lot of times you'll see something like this:
Or you can go here:
https://www.nhc.noaa.gov/
A lot of times you'll see something like this:
But you can also see something like this:
Initially, Celia's pressure was higher (and therefore less powerful).
But it dropped.
And now, combine with other factors forecast, Celia is expected to turn into a hurricane by Friday morning.
So when you go to the NOAA website and you see a storm, either hover your mouse over the red storm graphic or scroll down to look at the minimum pressure (indicated by red arrows).
Keeping your eye on that can help you decide how to respond and protect yourself during a storm forecast.
UPDATE: Davening for sure helps with hurricanes. See here:
did-teshuvah-tefillah-dissipate-a-potential-hurricane.html
But it dropped.
And now, combine with other factors forecast, Celia is expected to turn into a hurricane by Friday morning.
So when you go to the NOAA website and you see a storm, either hover your mouse over the red storm graphic or scroll down to look at the minimum pressure (indicated by red arrows).
Keeping your eye on that can help you decide how to respond and protect yourself during a storm forecast.
UPDATE: Davening for sure helps with hurricanes. See here:
did-teshuvah-tefillah-dissipate-a-potential-hurricane.html
For a previous post with similar information & illustrative examples, please see:
www.myrtlerising.com/blog/the-most-accurate-way-to-measure-a-hurricane-focus-on-the-pressure-reading
www.myrtlerising.com/blog/the-most-accurate-way-to-measure-a-hurricane-focus-on-the-pressure-reading
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