Dredd Blog: Last" Doesn't Always Mean "Previous

Saturday, January 24, 2026

Last" Doesn't Always Mean "Previous - 7

In a discussion with the Google AI, I stated "The high pressure 'H' on the weather maps yesterday was 1056. One of the meteorologists said that he had never seen one that high ..." The AI entity posted 'Thinking' ... then replied:

"A reading of 1056 mbar (approximately 31.18 inches of mercury) is exceptionally rare and would indeed be a career-first for many meteorologists. In the context of Winter Storm Fern (January 2026), this massive Arctic high-pressure cell is currently dominating the U.S. and is classified as "near record-breaking" for the lower 48 states.
Historical Context of a 1056 mbar High
To understand why your meteorologist was surprised, compare 1056 mbar to historical extremes:
Contiguous U.S. Record: The highest pressure ever recorded in the "Lower 48" is 1064 mbar, set in Miles City, Montana, in December 1983.
North American Record: Alaska holds the continent's record with 1078.6 mbar (Northway, 1989), recorded during an extreme cold wave where temperatures dropped to -62°F.
"Strong" Highs: Most powerful winter Arctic highs range between 1040 and 1050 mbar. Crossing the 1050 mbar threshold puts a system in the top 0.1% of intensity for most locations.
Why 1056 mbar Matters for Winter Storm Fern
While we often focus on low pressure for storms, this 1056 mbar high is the "engine" behind Winter Storm Fern:
Instrument Calibration: Pressures this high can actually exceed the display range of some home barometers and have historically required adjustment for aircraft altimeters to function properly.
The "Push" Factor: The intensity of this high creates a steep "pressure gradient." It acts like a massive plunger, forcing the frigid Arctic air deep into the Southern U.S., where it clashes with moisture to create the current ice and snow conditions.
Physical Effects: At 1056 mbar, the air is 4.2% denser than standard air. This extreme density is a hallmark of the "Polar Vortex" disruption that sent this air mass so far south."

(See Watching The Arctic Die - 7). I am wondering what a change in the mix of gases in the atmosphere at a particular Layer and Zone would have on that area's atmosphere.

I have been perusing the Lundstad et al. datasets, and putting them to the test in this series.

Today's graphs have been passed though the TEOS-10 SIA software I am converting from Fortran to C++.

After diagnosing the Lundstad dataset I ran it through some dry air functions in that library.

That function is the "air_density_si (a_si, t_si, p_si)" in the "Air_3b" module.

Let's look at some Lundstad dataset graphs after passing that data through the function that takes a_si, t_si, and p_si parameter data.

I used the temperature etc. sections of the dataset graphed previously in this series (see previous graphs).

The "Combined" graph below details the flow when all of the data in the individual zones are combined and averaged.

The graphs below the combined graph are individual layers in individual graphs.

Some are missing because some of the data failed to make it through.

But the clear message being shown is that the atmosphere is impacted not only by temperature, but also by the mixture of gases.

This is the description of the function that generated the data for the graphs:

============================================= function air_density_si (a_si, t_si, p_si) ============================================= This function returns HUMID-AIR DENSITY as a function of AIR FRACTION, TEMPERATURE AND PRESSURE from numerical iteration of the HELMHOLTZ FUNCTION DERIVATIVE ... OUTPUT: ... [density of humid air in kg/m³]

In other words more or less of gas X in the mixture causes one density phenomenon while others mixtures cause other density phenomenon.

I thing Dr. James Hansen has been criticized unfairly for his focus on the impact that the mixture quantities of aerosols changes atmospheric dynamics depending on the gases and their quantities in that mixture.

I am continuing research on this, but remember that adding more pollution by adding other gasses to the atmosphere is not an answer.

The answer is removing pollution from the atmosphere.

The previous post in this series is here.