# 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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### 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 ...
51 views

### 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 ...
1k views

### Do winds behave like waves?

Like a sound wave, there are compressed and dilated regions in the air. But do compressed regions also occur in winds. If one considers squalls, they feel like a compressed region of air. Perhaps they ...
16k views

### Why doesn't the 71% water of the earth dry or evaporate?

Perhaps a simple question, we know 71% of the earth's surface contains water as oceans. If Earth's age is 4.543 billion years, then I guess it should be decreased with drying or should have been dried ...
191 views

### Water on Mars and Earth

If water on Earth came from meteorites, why doesn't Mars have substantial water? What made it more highly probable on Earth than on Mars?
80 views

### 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 ...
75 views

### How to measure voltage differential across different altitudes

Imagine two points, one directly above the other ( Point A - 10,000 feet (PA) Point B - 20,000 feet (PB) Imagine there's voltage potential between those two points Q1: How could you measure the ...
75 views

### 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 ...
74 views

### 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 ...
51 views

### 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 ...
80 views

### Why did Hurricane Harvey have so much lightning associated with it?

Hurricane Harvey (Category 4 hurricane, in August 2017) was a prodigious lightning producer when it hit Houston/SE Texas. But I thought hurricanes don't have much lightning (with the eyewall being the ...
202 views

### What is the most optimal latitude on Earth for the generation of extreme maximum temperatures?

First question on this StackExchange, so here goes... Overall, reaching high temperatures is dependent on 2 factors: The (maximum) solar angle in the day. The greater the solar angle, the more ...
59 views

### 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, ...
33 views

### 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.
81 views

### What is a reasonable range of values for resistance to heat flux?

I am developing a simple parameterisation scheme script to predict surface temperature. The script calculates six heat fluxes including sensible heat flux using a resistance to heat flux parameter. ...
60 views

### 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, ...
11k views

### Continuous lightning for over an hour; is this phenomenon common and does it have a name?

A few months ago, I witnessed something off the coast of Florida that I have never seen in my life. From my apartment, from about 10PM - 12AM, I saw pretty much continuous cloud to cloud lightning. I ...
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 30Ā° clockwise to the wind on the surface due to the ...
32 views

### 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 ...
60 views

### 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 ...
68 views

### 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 ...
288 views

### What is the explanation of using pressure units (hPa) to express height when dealing with wind speeds?

I am trying to understand how prevailing winds and jet stream currents are formed and how they are varying in speed and direction. When looking at different wind speeds at different altitudes on ...
130 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 ...
888 views

### First to Sail the Jet Stream Around the World

My questions are related to a scenario discussed on Earth Science: A huge (heavier-than-air) kite sailing in and out of the jet streams. The kite: The scenario: The assumptions: Such an airship ...
33 views

### 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 ...
31 views

### 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 ...
17 views

### 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
104 views

### Why are there both climate regions from axial tilt and weather cells?

So Earth has an axial tilt and that creates weather regions. For example, approximately 23 degrees north and south, approximately the same as the planets axial tilt, will give you the tropics. This ...
82 views

### 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 ...
65 views

### 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 canāt retire their names. describes a complicated situation, aspects of which are: Eta roared ashore ...
31 views

### 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 ...
21 views

### 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, ...
42 views

### 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 doesnāt the subsidence layer ever reach ...
51 views

### 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) ...
51 views

### 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?
404 views

### 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 ...
583 views

### Desalination and Weather Impact?

I have a question I've always been curious about regarding the topic. As I understand it, the desalination process is that they take the salt water, create usable water from it and then salt sludge ...
52 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 ...
53 views

### 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 ...
36 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: Iām not sure if ...
186 views

### What kind of climate could you expect in a mountainous area in a subtropical region?

More specifically, I'm trying to work out climate analogues for my farm. It's at 5200-6200ft in South India. My area is a bit too small for the KĆ¶ppen Map to correctly reveal patterns. I'll be ...
41 views

### 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?...
58 views

### 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 ...
964 views

### Why is it colder in the mountains than at sea level?

I have heard numerous reasons why that is. I just want to know which one is right.
42 views

### 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 = ...
31 views

### 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?
592 views

### Madden-Julian Oscillation (MJO) - How to interpret the index?

How the Madden-Julian Oscillation (MJO) index can be interpret? Let's suppose I have got an MJO index value of 0.6 in a given day, what this does mean? Does 0.6 represents a weak MJO? Data from ...
133 views

### Does the Columbia Basin, North Cascades and Idaho Panhandle/Clearwater get a lot of violent, rotating supercellular thunderstorms?

Every storm season, supercells erupt in Montana and Wyoming. Wayward cold-core setups can trigger supercells or even long-tracked strong tornadoes in the Columbia/Willamette Valley and the rest of SW ...
76 views

### 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 ...