Questions tagged [meteorology]

The study of how the earth's atmosphere works, including weather forecasting. Use this tag for questions about the earth's weather. When asking questions specifically about the atmosphere, also include the [atmosphere] tag.

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2
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1answer
72 views

How does a whirling hygrometer work, how does it differ from static dry/wet bulb thermometer, and how to obtain humidity from its readings?

Answers to my previous question How is relative humidity determined from a wet and dry bulb readings? provide equations for converting the two temperature measurements to a relative humidity. In ...
1
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0answers
62 views

wrf_chemi file with 30 time steps

I creat wrfchemi file for my wrf-chem, my wrfchemi file has 30 time step, frames_per_auxinput5 = 30, 30, auxinput5_inname = "wrfchemi_d", auxinput5_interval_m = 60, 60, ...
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1answer
140 views

Does being in the air provide any protection from an asteroid?

How does radiation and shock waves from a radioactive asteroid or atomic explosion disperse throughout Earth's atmosphere? Are there specific areas on Earth that are less likely to receive the shock ...
-19
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2answers
1k views

Why aren't there more questions and concerns about chemtrails? [closed]

Chemtrails are amazingly obvious in our daily life but why aren't we more concerned? The information and patents for the chemicals we? are spraying are readily available. The chemicals are huge ...
45
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5answers
16k views

Why do snowflakes form into hexagonal structures?

Snowflakes are known to form into pretty hexagonal structures. The image below shows a variety of such structures that are possible (although by all means not an exhaustive list): What is the ...
17
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3answers
47k views

How to interpolate scattered data to a regular grid in Python?

I have three txt files for longitude, latitude and temperature (or let's say three lists lon, lat, temp) from scattered weather station in the UK. I would like firstly to interpolate these data in ...
32
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3answers
4k views

Why does Coriolis determine the rotation direction of a cyclone but not my drain?

It is a common misconception that Coriolis is responsible for the direction the water swirls down a toilet, tub or sink drain. E.g. does a toilet flush the other way in the southern hemisphere? (If ...
12
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1answer
1k views

Numerical weather forecasting - resources for a programmer?

There is a community wiki question over at A good book or source for climate science and meteorology basics? that talks about meteorology basics. Building on that, but with a slightly different focus,...
24
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2answers
2k views

What is the cause of the jet streams?

Jet streams are fast-flowing currents of air in our earth's atmosphere. An enormous amount of energy is necessary to keep a jet stream going. Where does this come from and why?
20
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1answer
799 views

What data does a skilled meteorologist look at to predict thunderstorms?

An uneducated layman like me would just look at CAPE numbers and make rough guesses on possible thunderstorms. In a related but non-duplicate question, vertical wind shear is discussed. If we are ...
16
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1answer
410 views

What is the methodology to analyze future climatic extremes using the results of climate models?

What is the accepted methodology to predict future climatic extremes using the results of climate models? I have recently read a report about climatic extremes considering climate change (MICE, 2002)....
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5answers
5k views

Is it true that a butterfly flapping its wings can result in a tornado in a distant location?

I have heard that extreme storm events can be caused simply by a butterfly flapping its wings somewhere in a distant location. Is it true that such a small disturbance in the air in one location can ...
16
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1answer
6k views

What do quasi-geostrophic and ageostrophic mean?

I know that geostrophic flow means straight wind flow that is balanced by the pressure gradient and Coriolis forces. But what do quasi-geostrophic and ageostrophic mean specifically?
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3answers
8k views

How would an icicle “grow” upwards?

The other day a friend of my dad's showed him a picture of an icicle that appeared to be "growing" upwards out of a crack in a sidewalk. There were no roofs, overhangs or vehicles parked near by... It ...
17
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1answer
416 views

Can climate models reliably predict meteorological extremes?

This question is related to and extension of my previous question which was about the methodology used to predict future climatic extremes: What is the methodology to analyze future climatic extremes ...
4
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2answers
5k views

Interpolate Gaussian grids to regular fixed grids using bilinear interpolation?

I want to regrid GCM data available on Gaussian grids to regular grids, say at 1 deg X 1 deg. How to do this using CDO or Python ...
18
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1answer
387 views

How is global weather model skill measured?

The models I have in mind are the major global models such as the Global Forecast System (GFS) and the European Center for Medium range Weather Forecasting (ECMWF). These models produce numerous ...
17
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1answer
629 views

Why are weather kites no longer used (much) operationally?

Figure 1.12 from the IPCC AR5 WG1 report (reproduced below) illustrates the different instruments that have been used for weather forecasting. Most of the methods have been in continuous use since ...
15
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1answer
3k views

How accurate are climate proxies in giving us a clear picture of global average temperatures throughout Earth history?

Since reliable modern records of climate only began in the 1880s, proxies provide a means for scientists to determine climatic patterns before record-keeping began, though it appears that the the ...
15
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1answer
367 views

What is the predictability of El Niño/La Niña?

What is the maximum period of time into the future that an El Niño event can be forecasted with reasonable accuracy and what are the limitations in predicting the time limit?
10
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1answer
293 views

Rainbow dynamics?

How would steam refract light compared to fog and how would the rainbow appear? Does the temperature of the water drop or ice crystal effect the rainbow in any way? I know the size of the water drop ...
10
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2answers
33k views

Have two hurricanes ever merged? And what was the result?

I was just reading this about how Hurricane Ethel could have merged with Hurricane Dora in 1964. Has such a merge ever happened before in history? If so, what was the result? Would storms become ...
7
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1answer
4k views

Can anyone recommend a good college level meteorology textbook?

I am trying to learn meteorology through self-study. I have found quite a few lectures on YouTube, but they tend to be for non-scientists. I have a strong engineering and physics background and am ...
21
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2answers
4k views

How do tropopause folds form and do they have any impact on synoptic scale weather?

What is the process that creates a tropopause fold? Do these features have any significant impact(s) on weather patterns or the atmosphere?
12
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1answer
466 views

How is the Rossby Radius used to determine that synoptic weather systems are 1000-2000km across?

In one of his presentations, Sandy MacDonald (of NOAA and ESRL) talks about the Rossby Radius of Deformation in connection with the size of synoptic weather systems: he describes how it sets the ...
9
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1answer
149 views

Why does air seem to affect local surface temperatures so much?

Last winter, several areas in the US and Canada were hit by a "polar vortex." I happen to live in one of those areas and was amazed how much the temperature seemed to change so suddenly just because a ...
9
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3answers
2k views

A good book or source for climate science and meteorology basics?

I have a mainly a hydro-geological and geo-statistical background, I would like to have a basic introduction to meteorological, climatic processes and modelling techniques related to these fields. Any ...
2
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0answers
150 views

Predicting the weather in two months [closed]

EDIT 6/13/2020: Actual Jan average from same website was 50.3 °F, which is even above my one-sigma bound, so I failed badly. What did I miss now that we have hindsight? On Nov 1, I looked at the ...
22
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2answers
844 views

How can the average coldest day of the year be before the winter solstice?

There are parts of the U.S. where, on average, the coldest day of the year comes before December 21st. [source] How can this be? Why would temperatures start rising again even while days are still ...
17
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2answers
2k views

Why are clouds darker before it rains?

What causes the darker color of the clouds (nimbus) when it is about to rain? Non-precipitating clouds (e.g., cumulus, stratus) tend to be white, but rain clouds become gray and almost black before it ...
17
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3answers
27k views

Why does the Inter tropical Convergence Zone shift?

I am currently learning at school about the climatic conditions (mainly winds, difference in pressure, Coriolis effect, etc.) that cause and affect the monsoons received by India. One of the factors ...
17
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1answer
6k views

What is the range of possible atmospheric pressures on the surface of the Earth?

I'm developing an Android app which uses a pressure sensor. Due to storage limitations I have to normalize and scale the atmospheric pressure values. For this I need to know the extreme values of ...
16
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3answers
3k views

Why does the so called “tornado alley” exist?

75% of the world's tornadoes occur in the USA, and within the USA these tornadoes are most likely to occur in particular regions of the country, such as the well known "tornado alley". The diagram ...
16
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1answer
3k views

How do urban areas affect rain?

Urban areas these days can be quite large, and they can have strong effects on the environment: the urban heat island effect being the most obvious, but there may be other, more subtle effects. The ...
14
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2answers
1k views

Why don't cold fronts and other steep-gradient weather effects just dissipate?

Why don't cold fronts and other steep-gradient weather effects just dissipate? Why do they last so long? Why doesn't the heat dissipate toward the cooler region?
12
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2answers
3k views

Are there some places near the equator that are hottest in their winter and some that are hottest in their summer? Is there a map of this?

Under this answer there's a comment: I am not aware of any location having its hottest temperature in winter... and for mid-to-polar latitude folks specifically we first learn that our summer is the ...
9
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1answer
192 views

Why should dynamical downscaling of meteorological data be made incrementally?

When downscaling meteorological data by using limited area models, many support forums recommended you to downscale incrementally in small steps. For example let's assume that your input data is on a ...
8
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0answers
142 views

What meteorological factors contribute to springtime Trans-Pacific air-pollution events?

The transport of tropospheric ozone, ozone precursors, carbon monoxide, etc from Asia to North America is an active area of research (see J.L. Ambrose, et al., 2011) These types of events occur ...
8
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2answers
195 views

What determines the differences in results between various weather models?

It's often said that the ECMWF model is more accurate than the GFS. But what are the reasons why? Also, how does the NAM compare with these two and other forecasting models?
7
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5answers
19k views

Rain without clouds?

Is it possible to have rain without visible clouds? As far as I know, clouds are liquid water and eventually the liquid water in them falls down, producing rain. Therefore one would expect clouds ...
6
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4answers
2k views

Does the Coriolis Effect affect a wind from East to West?

I'm studying meteorology for a pilot license and there I was taught as a rule of thumb that wind at higher altitudes is approximately turned 30° clockwise to the wind on the surface due to the ...
6
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1answer
3k views

How to calculate humidity using outside temperature and outside relative humidity?

I would like to ask how to calculate the relative humidity that a heated indoor area would have using only outside temperature and outside relative humidity. I found the Relative Humidity Calculator ...
6
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1answer
9k views

How to calculate relative humidity from temperature, dew point, and pressure?

Is there a formula given the temperature, dew point, and pressure to find relative humidity? I have seen several calculators like this one, but I would like to know how to calculate this myself. I ...
5
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2answers
899 views

Centrifugal Force in the Navier Stokes Equations

The Navier-Stokes equations are a set of nonlinear differential equations that diagnose wind speed and direction. They are (approximately) expressed as $$\frac{d\vec{u}}{dt}=-\frac{1}{\rho}\nabla P+f\...
4
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1answer
68 views

Freely available and re-distributable weather observations over the US?

I am looking for a (small) data set of weather observations for a few (say 5-20) weather stations in the US, with observations of precipitation, temperature and wind speed for the year 2016. The data ...
4
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1answer
235 views

Single-layer water content variables

In different reanalysis products (ERA 20C and NOAA/OAR/ESRL/PSD 20th Century daily data specifically) one can find the following variables: Total column water (ERA) Total column rain water (ERA) ...
2
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1answer
104 views

When and where is the atmospheric greenhouse effect strongest?

Is the greenhouse effect stronger in the ice covered area or in the equator? Also is it stronger during winter or summer? I am thinking it is stronger in the Ice covered area and during winter because ...
2
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0answers
47 views

Topographical model of a wind-farm [duplicate]

Has anyone ever built and tested a topographical model of a 200 mile radius with a wind-farm in the middle to see how much wind speeds and wind direction change when the farm is active compared to ...
1
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0answers
76 views

If its ice sheet were removed under modern atmospheric conditions, what climatic and ice-sheet equilibrium would be re-established over Antarctica?

Note the use of the term removed instead of melted—as in, any excess water is moved to where it can't cause trouble, either through the use of advanced technology (space elevators, et cetera) or for ...
19
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2answers
281 views

Will tropical cyclones form and be sustained in areas they previously were not due to global climate change?

With global climate change, is it possible that tropical cyclones (as seen in the Atlantic basin for example) are going to form and be sustained in regions where they previously did not, for example ...