Hot answers tagged

24

Tornadoes are the result of small-scale effects such as the convergence of updraft/downdraft regions in a single thunderstorm, the stretching or entrainment of vertical vorticity, wind shear profiles, and even friction with the ground. Hurricanes rely on massive amounts of latent heat release from an atmosphere moistened by warm ocean waters causing rising ...


14

There are two types of dust storms. The first, a dust storm or "sandstorm", is associated with a synoptic scale feature (like a low pressure system). Strong winds along air mass boundaries (i.e. cold front) create clouds of dust as sand, dust, or other particulates become suspended by turbulent eddies near the surface and aloft. The second, the infamous "...


13

The 2011 AGU poster has been cited once, by Burtin et al. (2013)1, who say in their abstract ... event activity was positively correlated with the precipitation intensity... -- but more importantly, in the body of the paper, this: Furthermore, it has been argued that rainfall may affect the occurrence of earthquakes, either by downward fluid diffusion ...


11

The major factors in temperature change from precipitation... First, fundamentally rain is falling to the ground from higher in the sky. Precipitation typically comes from a location where it is colder compared to us on the ground (the troposphere generally is cooler with height, on average around 6.5 Celsius\km.). Basically, the rain itself usually at ...


11

You are seeing the gust fronts or outflow boundaries of the thunderstorms around Denver. The rainfall from the storm provides an evaporative flux that cools the air it falls into (preserving $\theta_e$ of air descending from aloft). This cool air is more dense than the surrounding air at and near the surface and spreads out as a density current. The ...


11

You know, there hasn't been too much research into this... but there has been some. For the most part, it's been proven that a green sky most likely means that a thunderstorm is coming. According to a researcher: Green is significant, but not proof that a tornado is on the way. A green cloud “will only occur if the cloud is very deep, which generally ...


10

A page in the book Come Rain or Shine, A Weather Miscellany states that the cones were discontinued on June 1, 1984, due to their being superseded by radio broadcasts and other methods.


7

Sandstorms occur in dry areas, particularly deserts. The sand particles are fairly uniform in size. As the dry sand moves due to the wind it begins a leaping process known as saltation. Quoting the Wikipedia article: the initial saltation of sand particles induces a static electric field by friction The sand particles become polarized and as the ...


5

The article can be found here in Geophysical Research Letters: Fan, W., McGuire, J. J., Groot‐Hedlin, C. D., Hedlin, M. A. H., Coats, S., & Fiedler, J. W. ( 2019). Stormquakes Geophysical Research Letters, 46. https://doi.org/10.1029/2019GL084217 Abstract Seismic signals from ocean‐solid Earth interactions are ubiquitously recorded on our planet....


5

It is mostly due to the Coriolis effect (aka Coriolis Force). (Another reference here) Because of the Coriolis Effect, parcels of air (think of boxes of air) in the northern hemisphere are deflected to the right. This means that air around the subtropical ridge over the Atlantic ocean circulates clockwise. Think of a tropical cyclone as a parcel, or box of ...


4

The models are similar in that they simplify the rainfall-runoff relationship into a few parameters, and essentially use some kind of first-order coefficient to partition rainfall into infiltration and runoff. The differences are mostly in what other parameters are brought in, such as initial abstraction in the SCS method (i.e. some capture of antecedent ...


4

Yes, most storm chasers are risking their lives to take lightning photos. Your likelihood of being struck is obviously higher the closer you are to where lightning is originating from. However, lightning is highly unpredictable, and therefore, there is not much you can do to avoid all odds of being struck. One suggestion would be to take photos from inside ...


3

The SPC's changeover announcement webpage offers very useful information on the change, and is central to this answer... Correction: There were actually 4 categories prior to the change. The SPC used the "See Text" area for what is now designated as a "Marginal Risk". These did not have colors or outlines, but instead just the words "See Text" on the map. ...


3

This is going to be brief as on a phone : I welcome somebody posting a more complete answer. But the basic principle of large waves appearing from wind is: from a smooth water surface, the wind can produce only small ripples. But those ripples mean that the surface is no longer smooth. The higher the ripples get, the more surface there is for the wind to ...


3

For a general view of the surge in the region, the maps in u-surge give a pretty good idea of numbers and more affected regions. The USGS provides a comprehensive view of High Water Marks (HWM) in the entire region. If you are looking for observations, then the HWM database gives you the best spatial coverage. While HWM do not provide surge information per ...


2

IRI's (Ionospheric Research Instrument or HF Radio Transmitter) can be used to excite specific areas of the ionosphere. The resulting heat creates a high pressure system that can be then be used to push the jet stream or prevent it from moving. This is the type of equipment that world powers had in mind when they signed the Kyoto Protocol 50 years ago (...


2

hard to impossible to tell. In recorded history it was for sure one of those massive volcanic eruptions from Krakatoa, Yellowstone or Tambora. But in earth's history there were some impacts from meteorites or commets that must have been a lot more powerfull in terms of released energy than any volcanic erruption. My guess is the Vredefort crater in South ...


2

NOAA flies routine dropsonde missions into tropical convection if there is anticipated threat to land. You can find information about these missions in the routine NHC updates for each storm. This data is used in estimation of hurricane intensity and some of the models assimilate this data to improve storm track and intensity forecasts. You can learn more ...


2

Thunder is a manifestation of lightning, the sudden discharge of (static) electrical potential between cloud and ground, or cloud and cloud. That potential is built up through convection of vapor from low to high altitudes, typically tens of thousands of feet. Though possible in winter, though unusual, this kind of convection occurs mostly during summer ...


2

My house elevation is 9.1 feet above sea level, according to all "expert" measurements. That includes the city, county, state, Feds, and all insurers. It seems about right to me. But then again, I cannot dunk. I live a half mile or so from the beach and bay of mustang island. Anyhoo, the static water level In my hood was 2-3 feet and a little less inside ...


2

The main driving force for storms to form at all are the equator-pole temperature gradients. The main reason for them to stop is friction between the lower atmosphere and earth's surface. This friction counteracts geostrophic balance (the balance between the pressure gradient and the coriolis force). Longer storms can only sustain themself through latent ...


2

An article here says 4 meters. (No statistical data however, just a general information page) Waves on Lake Baikal may reach a height of 4 meters. Sometimes they evaluated as 5 and even 6 meters, but it is most likely an estimation “by eye”, which has a large error. Height of 4 meters obtained by instrumental measurements on the high seas. Another ...


1

I'd have to say a tornado would be more dangerous than a straight wind of equal speed. Tornados have a very low-pressure center and violent updrafts as can be seen in this YouTube video . As the roofs are blown off you'll notice they get blown upward as well as sideways.


1

A typical ratio calculated to quantify this type of response, especially at larger scales (such as for land use changes) is the runoff ratio: $$R = Q/ P$$ where $R$ is the runoff ratio [mm/mm or dimensionless], $Q$ is the annual flow volume [mm], and $P$ is the annual precipitation [mm]. The runoff ratio is usually calculated for a given data period (...


Only top voted, non community-wiki answers of a minimum length are eligible