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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Which factors determine the predominant precipitation type of supercells during tornado outbreaks?

A tale of two outbreaks. April 27, 2011 featured classic supercells that were extremely-fast moving (forward speeds of 60+ mph) in a northeast direction. James Spann noted this while covering the EF4 ...
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Why is it so warm in the Pacific Northwest of North America right now - mid April 2021?

Temperatures are 5-7 degrees Celsius above average in southwestern British Columbia, and it's surreal for it to be so warm and sunny when the deciduous trees are still mostly barren.
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What does a change in the mean pressure across 750 km indicate/signify?

Coming from the aviation site: What is the westerly index? The westerly index is: ... the Trenberth Z1 index (Trenberth 1976), which is the departure of the monthly mean pressure difference between ...
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Snow on a relatively warm day

Outside my window it's snowing. This isn't so strange, even for the South of England in mid-April. What is surprising is that the ambient air temperatures (according to the Met-Office) are about 7 or ...
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What is “small layer thickness” defined as in terms of bulk Richardson number approaching gradient Richardson number?

In may sources (https://glossary.ametsoc.org/wiki/Bulk_richardson_number), bulk Richardson number is defined as an approximation to gradient Richardson number. The prior only approaches the ladder ...
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Determining probability of precipitation from GFS data

Looking at the index files in https://ftp.ncep.noaa.gov/data/nccf/com/gfs/prod/, there's no probability of precipitation (POP) data provided. (There is a ...
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1answer
72 views

Why does Japan get so much snow?

Japan seems to get a surprising amount of snow in winter, compared to other places that are as cold or colder. The snow seems to be concentrated on the west side of the country, which suggests the ...
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How to specify a certain place in a (CDS) weather data query?

I am trying to get time series data for a specific place (latitude and longitude) for different weather elements from the CDS datapool. Therefore, I am using the cdsapi package and can run queries ...
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Why is the mean meridional mass stream function multiplied by g/2π?

I was reading this material on the mean atmospheric meridional circulation and the definition of the meridional mass streamfunction: http://www.geo.cornell.edu/geology/faculty/Cook/Hadley_book.pdf (...
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Relation between Magnitude of Greenhouse Effect and the Concentration of GHGs like $CO_2$

The Average Surface Temperature of the Earth is calculated by the following equation: $$\sigma T_s^4=\frac{(1-A)\Omega}{4}+\Delta E$$ where, $\sigma$= Stefan-Boltzmann Constant $T_s$= Average Surface ...
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Why are January and February the coldest months although 21 December is the shortest day? [duplicate]

My question deals with the northern hemisphere only, obviously. It seems to me that January and February are the coldest months of the year. Water temperature is even more 'retarded': the seas are ...
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1answer
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How to calculate the specific humidity based on the saturated specific humidity?

I am using ERA5 data to drive the land surface model. One of the forcing required by LSM is specific humidity. We want to use the 2-m specific humidity. So how can I calculate the specific humidity ...
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Relationship between rainwater and solar radiation

I am an enthusiast in this area and reading some scientific articles on precipitation forecasting and solar irradiation, I was wondering if these two variables have any direct correlation or ...
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Question regarding an ice age caused by impact event(s)

If a hypothetical series of debris were to collide into a planet like Earth, I'm aware that dust could very well be sent into orbit, causing global cooling. If this were to happen, exactly how would ...
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High vertical resolution atmospheric sounding data

I'm currently doing some analysis using atmospheric sounding data available at University of Wyoming (I assume these are from the GTS network). But, the vertical resolution of the sounding data ...
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A database with measurments of meteorological parameters at various altitudes

I am a P.h.D student working on effects of Evaporation duct on radio propagation. Pandemic is successfully stopping me from obtaining my own measurements for my thesis, but I would like to compare the ...
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Is a hotter climate making trees grow faster and have lighter wood?

I started thinking about this after seeing several articles about falling trees, in particular a few articles about very large trees falling in Los Angeles and New York City. Plus, just thinking about ...
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Korea a lot colder than New England this year

Normally, here in New England we consider our weather to somewhat parallel Korea's weather. However, this year it seems to be much colder in Korea. They are having record lows while we are having a ...
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difference between different meteorological models

I need to work with historical weather data (temperature and precipitation), we use meteoblue.com. There (https://docs.meteoblue.com/en/meteo/data-sources/data-sources#data-sources) they write about ...
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Is the weather of Miami, Florida and the weather of Lagos, Nigeria the same

I've been to Lagos and it rains a lot sometimes overflooding but it's pretty sunny. I'm aware that it rains a lot too in Miami. Is the climate the same apart from Lagos being near Equator and ITCZ ...
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What factor(s) could cause this sort of temperature increase, mid-night/early morning?

I am new to having a PWS (Personal Weather Station). I have not found any answers explaining why this sometimes occurs aside from explanations given factors that were not variables in my case (winds, ...
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Why is the weather in San Francisco so different from that in San Jose?

San Francisco has around 5 months a year of intermittent rain. San Jose, just 50 miles south and nestled between mountains instead of between waters, has perhaps only 1 month of rain. San Francisco ...
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Free historical weather data API

Where can I find a free Python API that provides historical weather data (temperature, rainfall)? I'd need data of an Italian city, at least with hourly granularity.
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How to measure global temperature?

people always talk about global temperature (such as the global temperature goal of 1,5 K) - but how is this value achieved? It seems to me that it clearly depends on where the measuring stations are, ...
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Is there an average year of weather across the United States?

I am interested in which year has the best representation of average weather across a large area, the contiguous USA. This is challenging since what was average in the Midwest might have been unusual ...
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Relative Humidity approximation from Dew Point and Temperature

I would like to find a formula to approximate RH based on known air temperature and dew point. I need the approximation to be valid at least between -20...+40 degrees Celsius. I read the accepted ...
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Why does wind direction change in a front? [duplicate]

Plenty of answers answer the question that it happens but I can't find a good answer as to why the wind shifts during the passing of a front. For an extreme example see: (in Dutch, x is hours and y ...
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134 views

Over what distance can weather be assumed to be constant?

Good afternoon, I'm working on an application makes calls to a weather API for different coordinates across the United States. Instead of getting the weather at each and every point, I'm planning on ...
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What are the leading methods for temporally interpolating wind data?

Weather providers, such as GFS and ECMWF usually provide their data in 3-6 hour intervals. What would be the best method to interpolate between the intervals to get a good intermediate wind model? I ...
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Historical detailed rainfall recordings New Zealand

I'm wanting to know where/if I can find 2019 records of hourly rainfall in New Zealand particularly for November in Greymouth South Island
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Why exactly did the use of Greek letters as names for Hurricanes happen the first place, despite the fairly obvious and predictable impracticalities?

The Washington Post article Hurricanes Eta and Iota brought disaster to Central America. Officials can’t retire their names. describes a complicated situation, aspects of which are: Eta roared ashore ...
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what elevation is top of southeastern US summer humidity/haze layer?

We're interested in purchasing a vacation lake house in the piedmont/foothills of North Carolina. In earlier summers there, when driving from the mountains home to lower (sub-1000ft) elevations, I've ...
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I would like to know where can I get historic global/national (preferably USA) level time-series data for the following (preferably gridded data)? [duplicate]

I would like to know where can I get historic global/national (preferably USA) level time-series data for the following (preferably gridded data)? Flood, Drought, Max temperature, Min temperature, ...
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Subsidence Inversion

With minimal knowledge of meteorology I understand how a high pressure system might lead to an inversion that builds as a high becomes more established, but why doesn’t the subsidence layer ever reach ...
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Why does the annual temperature range get bigger where latitude is higher?

Why does the annual temperature range get bigger where latitude is higher? Is it because of the ocean currents? Or is there any other factor that causes this situation?
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What are Atmospheric Rossby Waves and how do they affect the weather?

I've been researching Atmospheric Rossby waves but from the multiple sources I used they all seem to be in conflict. Some say Rossby waves are parcels of air moving from east to west due to the ...
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Lightning activity day curve - why it has high and narrow peak?

Atmospheric potential gradient changes during the day, as different areas of lightning activity come under Sun. This illustration from "The Carnegie Curve" by R. Giles Harrison shows ...
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Question on the derivation of a prognostic equation for the mean concentration (Assume horizontal homogeneity in X)

In deriving the prognostic equation for the mean quantity of pollutant C, as shown in my solution below: Am I right in that I do not need to separate T (temperature) into its mean and turbulent parts ...
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54 views

Vertical air speed

Assuming that the divergence varies linearly with the pressure between the surface (1000 hPa) and the tropopause (200 hPa). Can someone tell me how do we calculate the vertical speed on the pressure ...
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1answer
39 views

Horizontal momentum flux in the surface layer

Given the question below, how would the kinematic momentum flux be at the surface layer? For letter a, why would it be that way (positive, negative, or 0)? Based on the answer below: I’m not sure if ...
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1answer
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Recommendations for books on boundary layer Meteorology?

Does anybody have any recommendations on books tackling Boundary layer Meteorology? I've seen the book by Roland Stull and Arya, but are there any other more updated ones that are as good as these two?...
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Weather produced by symmetric cold core cyclones

I know that, although rare, there are symmetric cold core cyclones (with a few of them even having a shallow cold core). They encompass some occluded extratropical cyclones, some dissipating tropical ...
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Why do cold-core lows slope towards the cold air with heigth? How to show mathematically that wind intensifies with height in this case?

I understand that from the hypsometric equation, in a cold core low the pressure gradient must increase with height, because in the center the isobars will be closer together: quente = hot, frio = ...
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Can I average the two RMM values?

The RMM values are sometimes quite different. Can I average the values of RMM1 and RMM2 and use it as an index for MJO?
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Can a Humidity Differential move PM2.5 Pollution?

Observations There is a higher level of PM2.5 pollution outside of the house. Readings are in the 80-150 range due to wildfires. (PM2.5 levels determined by sensors in PurpleAir.com's sensor network) ...
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How do I find the temperature of the air mass, and how do I use a t-skew chart?

So the first problem I'm stuck on is this one: An airmass is moving down a mountain from point A to B. At A the temperature is -10 Celsius and the pressure is 890hPa. At point B the pressure is 1010 ...
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Has a hurricane ever crossed the Atlantic Ocean more than once?

I noticed that Paulette (2020) is still a named storm and is now approaching northern Africa and Spain. It is forecast to begin moving west again in the coming week. Has a hurricane / tropical storm ...
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How to interpret the negative (actual) evapotranspiration values?

I am exploring FLUXNET sites for actual evapotranspiration (ETP) data (I convert the energy balance closure-corrected latent heat to ETP). I am interested in the half-hourly data. During the night we ...
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How do upper-level cyclones and anticyclones affect surface level winds?

Take something like the Bermuda High, for instance. I drew a crude illustration of it. It steers hot, humid air from the Gulf of Mexico towards the east coast of North America. But upper level winds ...
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In a mesocyclone, why does wind shear create a horizontal axis of spinning air?

Take a look at this picture. Moist updrafts interact with highly-sheared upper-level winds, which sets up a horizontal vortex. But why? What causes the air to be forced downward and to the right, then ...

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