Hydroclimatology and Solar Explorations

Climate & Weather Representations, Climate Forecasts & Predictions

Probable Maximum Precipitation in Colorado and New Mexico

Hydrologists routinely must estimate the PMF, or Probable Maximum Flood, for a given stretch of river.  This is similar to the so-called 100 year flood.  Both are related ultimately to the probable maximum precipitation (PMP), as well as many other important parameters.

My featured work on streamflow forecasting [1] often overlaps with these exercises, simply because the maximum of a streamflow is predicted in the context of the average streamflow.

A recent study [2] coauthored by scientists from NOAA and CIRES and funded by divisions of Colorado and New Mexico, claims to derive improved forecasts for the PMP, based primarily on climate change models which they downscaled towards these two states.

Their report appears to disregard the solar-forced streamflow phenomena which my work features.  There is no mention of solar forcing beyond one nominal introductory sentence.  There are 18 entries for the “emissions” term, which always refer to the notion that anthropogenic greenhouse gases drive temperature patterns.  In the authors’ assertions, rising greenhouse gas levels result in decadal surges in temperature, not only across the entire planet, but also across my study’s region (NM to Colorado).  They confidently conclude that these will drive up the magnitude of the PMP.

I confidently conclude that if their word is accepted, then additional taxes in one form or another will be extracted from us to foot the bill for much larger dams and flood control structures, as well as upgrades to bridges and many other engineered infrastructures, including for example, ubiquitous drainage structures.  I assume the costs would be staggering.

My concerns about that study are manifold.  First I have emailed each of the authors to share with them the good news of my published paper.  It includes much more accurate forecasts of streamflows in the region than they were able to achieve.  And it doesn’t include any alarming projections that come with gargantuan price tags.

Another concern relates simply to their descriptions of temperature over New Mexico and Colorado.  The featured image at the top of this post demonstrates.  The top curve represents their depiction of temperature changes over time in New Mexico.  The next curve below that one (within the same featured image) is my reproduction of a readily available ground temperature record from Chama, New Mexico [3], relatively high in altitude (where most of the precipitation occurs) and close to the Colorado border.

The lowermost curve of that featured image represents my extraction of full atmospheric thickness (‘fat’) temperature  equivalent [4], over most of the satellite record, and averaged over the New Mexico footprint.  As the figure below shows, from a previous post, typically these temperature patterns have been flat, and this extraction is no exception.  Here is a reproduction of the temperature examples from that post.

Between the temperature records I have extracted and the temperature record asserted by Mahoney, Lukas and Mueller, we each cannot be right.

I am sure they are fine scientists/engineers and likely could teach me some things.  But I confidently believe they are wrong about temperature records.  I also know that my paper [1] demolishes their claim that temperatures in New Mexico and Colorado are the cause of precipitation in those states.

As this web site profiles frequently, solar irradiance and its cycles over decadal time spans, appear to account for the atmospheric moisture patterns, which in turn impact precipitation across the planet and notably in this region of Colorado New Mexico [1].   If anything, temperatures have remained relatively FLAT across the decades, across this region and the planet.  If anything, the moisture patterns impact the temperatures rather than the tail-wagging-the-dog assertions of Mahoney, Lukas and Mueller.

Here again is an animation I routinely post lately, which shows the temperatures across the Pacific and includes our New Mexico Colorado region.  The only noticeable blips in temperature happen in a small turquoise triangle straddling the border between those states.  Those blips are DROPS in temperature and they appear to occur when atmospheric moisture is higher.


global temperature fluctuations 5 year trailing average several recent years A by mwa

It is common for scientists to make assertions that temperature drives precipitation.  Their mistake appears to commonly relate to some implicit notion that the atmosphere is not really CIRCULATING.  Moreover, most as well don’t appreciate the fact that oceans always can produce enough evaporation to regulate our planet’s atmospheric temperature.  The moisture patterns are dynamic in their behavior in response to solar irradiance over any conceivable scale.  In a manner not unlike our own human temperature regulation through perspiration, global water’s dynamic transport and related capture and release of latent heat ensures a relatively equable, global temperature regime.  The satellite record proves it.


[1] Wallace, M.G., 2019, Application of lagged correlations between solar cycles and hydrosphere components towards sub-decadal forecasts of streamflows in the Western US.   Hydrological Sciences Journal, Oxford UK  Volume 64 Issue 2.   doi: 10.1080/02626667.2019.

[2] Mahoney, K., Lukas, J, and Mueller, M., 2018, COLORADO — NEW MEXICO REGIONAL EXTREME PRECIPITATION STUDY.  Summary Report  Volume VI   Considering Climate Change in the Estimation of the Extreme Precipitation for Dam Safety.  jointly published by the Colorado Division of Water Resources and the New Mexico Interstate Stream Commission.  Nov. 30, 2018.

[3] Berkeley Earth database.  This station is identified as:
Berkeley ID#:  31688 Primary Name:  CHAMA NWS AWRS

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