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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5
votes
2answers
305 views

Pressure of condensation of an air parcel

If a parcel of air ascends adiabatically, would condensation be reached at the lifting condensation level (LCL) or the level of free condensation (LFC)?
10
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1answer
1k views

How to calculate relative humidity?

I am involved in developing a weather based application which needs to calculate relative humidity and display it. I grab other weather variables like temperature, precipitation, wind speed and ...
9
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3answers
593 views

Obtaining hourly weather data, including direct and diffuse insolation

I really need some reliable measured hourly weather data for a few sites across the world. It needs to include solar diffuse and direct values or their equivalents. I've tried the usual sources: Met ...
9
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1answer
1k views

A parcel of air in an isothermal layer

I'm having a bit of trouble figuring out a solution to this problem: There is an isothermal layer of air which has a temperature of 0 °C extending from the surface to 1 km height. A parcel is 0.5 °C ...
5
votes
1answer
443 views

How do I interpret the specs of a weather balloon?

I'm planning a high-altitude weather balloon project (to around 100000 feet, or 30 km) some time down the line to take video and pictures of near space altitudes and I have some questions I need to ...
7
votes
1answer
253 views

Resources to determine temperature probability for a given location on a given date

What tools or resources are available (free) on the web to determine the probability of a given point on the earth to be at or above (or below) a specific temperature on a specific date. Some [...
14
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2answers
904 views

How can odor travel be tracked

Odd question, but what data would be needed to to calculate how far winds will carry a strong odor (such as the smells of a restaurant, pizza parlor or burning wood/building? There is wind direction ...
16
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1answer
2k 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 ...
11
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1answer
772 views

How much energy is needed to alter the path of a hurricane?

Suppose we spot an Atlantic hurricane very early. How much energy should we expend to alter its track: with nuclear detonations (let's forget about the side effects for the moment)? with a large ...
25
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3answers
3k views

Equinoxes and solstices: start of the season or mid-season?

In the United States, the upcoming autumnal equinox is marked on most calendars as the "first day of autumn." Similarly the solstices are commonly called the "first day of summer" and "first day of ...
3
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3answers
922 views

Regarding the melting glaciers and icebergs, why isn't the extra water vapor in the atmosphere mentioned in discussions of global warming?

As is reported on the major news networks, many glaciers and big icebergs are melting, which reportedly causes a tremendous increase in the amount of water vapor in the atmosphere. Now a lot of ...
10
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2answers
771 views

Why is q used for specific humidity?

$q$ is the symbol used for specific humidity in many textbooks and papers (at least in meteorology and climatology, I'm not familiar with it in other disciplines). Where does this symbol come from, ...
11
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1answer
268 views

Sea breeze - magnitude of horizontal pressure gradient?

What is the range of horizontal pressure gradients typically caused by the differential heating of land and water under sea breeze conditions?
13
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1answer
891 views

How significant is a 5-10 mb drop in pressure over a 20 minute period?

I would be interested in seeing how significant a 5-10 mb drop in pressure would be at the surface, and 80 m in the air. The temporal scale would be 20 minutes. If the pressure starts to steadily ...
21
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1answer
15k views

Do tornadoes have eyes?

In the movie Into the Storm (2014) near the end, storm chaser Pete sees the eye of a massive tornado. In 1928 (real life), Will Keller was in his barn when a huge tornado passed through. He reported ...
10
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1answer
539 views

Why do rainbows appear to have a fixed structure?

Why do rainbows appear to have a fixed structure when a bunch of raindrops are 1. moving, and 2. granular?
22
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3answers
44k views

How do I convert specific humidity to relative humidity?

How do I convert specific humidity to relative humidity? What variables are needed (e.g. air temperature, pressure, etc.)?
8
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1answer
126 views

Why does the Northern polar vortex usually have two centers?

From http://glossary.ametsoc.org/wiki/Polar_vortex polar vortex A planetary-scale mid- to high-latitude circumpolar cyclonic circulation, extending from the middle troposphere to the ...
11
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1answer
281 views

How can you explain this storm phenomenon?

It's been a while since this happened, so I don't have many details. About 3 years ago, we had a popup storm here in Louisville. It was completely unexpected and unpredicted. That's not the strange ...
3
votes
1answer
1k views

Why do some places have rain frequently? [closed]

There are some places on Earth which holds the record of being "The wettest place on Earth". On what factors these places differ from other normal places? An example of wettest place on Earth is ...
10
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1answer
98 views

North Indian ocean tropical cyclones

Why are tropical cyclones in the Bay of Bengal more frequent and stronger than those in the Arabian Sea?
6
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1answer
196 views

Am I observing orographic rainfall?

I don't know an awful lot about meteorology, so please bear with me. My wife (who has a Geography degree) told me that rain can be generated when moist air is pushed up the side of a mountain. This ...
10
votes
1answer
708 views

How could humans alter storm intensity or direction other than cloud seeding?

I am familiar with the concept of cloud seeding, where precipitation can be induced with aerosols, thereby altering storm intensity further downwind. Are there methods that could be used to ...
7
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0answers
429 views

Calculating Monthly Accumulation value of the Clearness Index KT

I have an hourly data file of a particular location which contains the following variables (extracted from the Meteonorm7.0 data base, for a typical one year of data): GlobHor (W/m2): Horizontal ...
18
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2answers
5k views

What are the applications of hydrostatic solvers vs non-hydrostatic solvers in numerical weather prediction?

In the atmospheric dynamics research community, many colleagues of mine happen to use atmospheric models that have non-hydrostatic equation solvers, e.g. the UK MetOffice model, and WRF-ARW: The ...
13
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1answer
155 views

Great Lakes - cookie cutter clouds

On 2014-07-10, in the afternoon, the GOES East satellite image in the visible showed a mass of cloud in central North America. However, in the middle, the Great Lakes stood out in a most extraordinary ...
8
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0answers
135 views

Relation of El Niño to Monsoons

Scientists are forecasting a weak to moderate El Niño event to emerge in the coming months, what causes this to happen? Once developed, how will the El Niño conditions effect progressive monsoon ...
19
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1answer
1k views

Why is there no middle ground between tornadoes and hurricanes?

A tornado has an effective area of destruction about the size of a city block. A hurricane spans several hundred kilometers. However, there doesn't seem to be a continuum between the two. Why are ...
9
votes
1answer
64 views

Is there a reliable way to identify regions with negatively-correlated winds?

When examining the potential for large-scale electricity grids, and when identifying the lowest-cost ways to generate clean electricity, a recurring theme is of spreading wind generation across a wide-...
12
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1answer
426 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 ...
20
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1answer
750 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 ...
10
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1answer
133 views

Is there a convenient place to get vertical wind shear info for my location?

Now that it's thunderstorm season here in New Hampshire, it would be nice to be able to find out what the vertical wind shear is like at the altitudes that affect thunderstorm formation, to guess ...
10
votes
1answer
893 views

What are Tetens coefficients?

Tetens coefficients appear in a few meteorological/climatological models that I've been looking at,for example APSIM: svp_A = 6.106 svp_B = 17.27 svp_C = 237.3 ...
9
votes
1answer
479 views

How can I downscale daily values of relative humidity?

I have a dataset (The ISIMIP interpolation of CMIP5 output) that contains daily values of the following variables: ...
10
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2answers
4k views

Is the urban heat island effect stronger during a particular season or part of the year?

It is known that cities tend to be warmer than the surrounding landscapes, and this is known as the "urban heat island effect". In the summer there is greater heat output from air conditioning ...
6
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1answer
4k views

Why is Sacramento so warm for its latitude?

http://en.wikipedia.org/wiki/Sacramento,_California It has high winter temperatures and high summer temperatures too.
7
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1answer
130 views

Does over-cropping large areas really change the amount of rainfall?

I heard that at one time the Sahara desert was cropped in wheat for the Roman Empire, and that cropping without adding back to the soil was what caused the desert to form. I also heard that this is ...
5
votes
1answer
2k views

If there's acid rain, is there such thing as acid snow?

If so, would the acid snow just be as damaging?
11
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2answers
360 views

Propagation of sound after lightning

In an area of frequent thunderstorms, I notice a 'crack or whoosh' sound if a strike is nearby but little or no thunder. Yet I can hear for 30 seconds or so after a distant flash when the thunder ...
23
votes
3answers
746 views

How good were climate models of the 1990s at predicting the global temperature trends of the 2000s/2010s?

Was there a significant bias between the ensemble of climate models and the long-term temperature trends? What about spatial patterns?
11
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1answer
3k views

Winds in a northern hemisphere hurricane

In the Northern Hemisphere, do surface winds around the center of a hurricane move counterclockwise and inward or counterclockwise and outward? I'm guessing they move inward.
12
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2answers
154 views

What is a source of worldwide temperature data that also includes extreme weather?

I often need to calculate heat balances for large biogas plants, an important factor is outside temperature. I normally use the weather data from Klimadiagramme.de where I can find the mean monthly ...
14
votes
2answers
6k views

July/August hottest months (northern hemisphere): because of continued warming or other effects?

In the northern hemisphere, July and August are the hottest months statistically1, but the days start shortening after June 21st. Is this just because the Northern Hemisphere keeps heating up after ...
14
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3answers
15k views

If it rains harder, does it mean the rain's duration will be shorter?

If it rains real hard, is there a chance the rain's duration will be shorter? I think the if the rain in the clouds disperses with such force the rain will be over faster than if it was just a light ...
11
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3answers
233 views

Is it right practice to validate temperature data with reanalysis data?

For a project I am working on I received raw data from many meteorology stationes. Is it right practice to test this data against air temperature from noaa's ncep/ncar data?
19
votes
2answers
15k views

Where can I get archived hourly temperature data?

I am looking for historical hourly temperature data from many cities in the US what other data sources are there except wunderground? UPDATE: I will use the data to compare stations from the same ...