posted on 23 October 2015
by Sig Silber
According to The Weather Channel the most powerful tropical cyclone ever measured in the Western Hemisphere, as its maximum sustained winds reached an unprecedented 200 mph (320 kph) and its central pressure fell to 879 millibars (25.96 inches of mercury), made landfall at 6:15 pm CDT near Cuixmala, Jalisco state of southwest Mexico.
The wind speeds at landfall had diminished to 165 mph, still a category 5 hurricane. The storm track is projected to progress northeastward, reaching the lower Rio Grand Valley and entering Texas early Sunday.
An earlier version of the graphic below (showing both the Pacific and Indian Oceans and a bit of the Atlantic) appeared in my Monday Weather and Climate Report and when it was updated on Tuesday, I knew we might have a problem. This version of the graphic updates on Fridays (today) and just shows the Tropical Pacific and part of the Atlantic.
You can see how moist air (actually precipitation) was projected to cross over Central America and be in the Gulf of Mexico and over Texas. That process has been ongoing. This alerted me to the possibility of some dramatic weather occurring. I was thinking more along the lines of the South Carolina tragedy (which also had the pattern of Pacific moisture being in place over South Carolina when an Atlantic storm came close) and I assumed the tropical storm off of Mexico would quickly go aground and dissipate with fairly minor damage. Unfortunately it hovered off the coast and extra day or two and gained strength.
What I have noticed is the pattern of Pacific Highs and Lows turning some of these storms inland when usually they are turned out to sea, in which case they are fairly harmless at that point except to shipping (unless they end up near Hawaii). There are many variables at play here.
Our overall situation is El Nino conditions but with a slight variation of also having a lot of warm water (probably unrelated to El Nino) north of the Equator not just on the Equator. This is shown, not that clearly, below but it is up to date. You can see warm water along the coast of Central America. It is even more intense further north off of Baja California.
Below is a Day 3 forecast, but this pattern has persisted for a few days.
One feature is the very strong Aleutian Low very indicative of a strong El Nino. But another feature is the diminutive Eastern Pacific Subtropical High. It is not a major feature other than not being strong enough to sweep these storms out to sea - also possible trapping these storms i.e. if they do not get turned out to sea right away they try to avoid this High by turning to the right which forces them to make landfall.
These two graphics might be of interest. The first is a snapshot of the Equator on October 4:
The second is the condition report today which means a five day average as of yesterday. By the time you read this it may have updated one day (update not shown here).
These graphics show the surface conditions close to the Equator in the Pacific. They are a pair of graphics the top member of the pair shows the actual values and the bottom the deviation from what is normal for this time of the year.
Notice in the bottom half of the second (current) graphic the warm anomaly shown by shades of red has moved to the east as compared to the situation on October 4. That happened a couple of weeks ago but did not last long. Notice the 3C+ anomaly. As an aside, one can now see the new Kelvin Wave over at 170W which appears fairly minor but will extend the duration of this El Nino a month or two. I do not conclude that his pattern is the cause of Hurricane Patricia but the result. It is a dramatic change from just yesterday. I monitor this daily.
And here is the latest Tropical Weather Outlook including the pattern of the water vapor.
The point I want to make here is this storm was generated by two oceans not just one. I do not know how common that is. Also note the extensive fetch of water vapor for this storm to work with. It most likely will have its winds dissipate quickly but it will be a big rainmaker.
Here is another view which shows how it might impact the entire CONUS, even reaching into Canada:
Remember this storm is spinning counter clockwise. So it is drawing in moisture from Texas and the Gulf of Mexico moisture that El Nino previously moved there and which was shown in the second graphic.
One additional note. I have a good friend who must remain an "anonymous source" for professional reasons. After Hurricane Katrina he ran a simulation to see how cloud seeding might have impacted the situation. The storm (in simulation) was not significantly reduced in intensity but it did veer to the left. I believe there is lots of evidence including some historical experimental results conducted by New Mexico Tech with GE that show it is possible to change the direction of a Hurricane.
Trying to kill a hurricane is more difficult because of the concentric bands around the eye. You can kill the eye wall by over-seeding it and having it rain out but the next band recreates the eye wall. So killing a hurricane is not realistic other than perhaps some short term relief for a population center. But redirecting it is.
There is a treaty that precludes the use of weather modification for military purposes. One wonders if redirecting Patricia to the left somewhat would have sent it out to sea or just further up the coast before it made landfall. I am not qualified to answer that question but others are.
Here is a wish for safety for those in Mexico and Texas.
Read a follow-up on Patricia in the next regularly scheduled weekly report early Tuesday morning.
Special note: In addition to writing the Weather and Climate column for GEI and other water related activities, I am a Supervisor of my local Soil and Water Conservation District. It is not usual for a SWCD but we happen to have seven flood control dams to manage. It is very unlikely that a storm like this would cause one of our dams to fail. But "very unlikely" is not the same as "impossible". So I worry about these things and also the activities of others to declare National Forests as Wilderness Areas which generally precludes forest thinning. Failure to thin forests is a prescription for serious wild fires and wildfires are a formula for silting in dams. That would then trigger a need for a very large amount of funding and that funding is not available. It is one of the reasons I have worked hard to be able to monitor weather and climate.
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