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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15
votes
8answers
8k views

Is it possible to create an enclosed manmade weather system?

There are plenty of experiments, usually geared toward kids, that involve "making a cloud in a bottle" or something similar. These exercises are neat for what they are, but pale in comparison to the ...
15
votes
1answer
268 views

What is the status of meteorological data exchange standards?

How do the web services exchange meteorological data? One method is transferring NetCDF and GRIB data and hooking them up to your software. I read here about the possibility of using WFS and WCS. ...
10
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1answer
655 views

Resources for learning the technical parts of atmospheric modeling

I'm a computer/atmospheric science undergrad and I'm trying to get into atmospheric modeling. Any recommendations for resources to get going or to learn about approaches? I can handle fairly technical ...
12
votes
1answer
416 views

Relation between direction of shear and tropical cyclone formation

In an earlier question/answer Why are there no cyclones in the southern Atlantic basin there was a point raised about direction of shear(abetting/retarding) cyclone formation. It appears ...
5
votes
1answer
572 views

How to determine that sustained wind speed exceeded the threshold value?

Certain maritime ports and airports have ranges of operation relation to the wind, usually according to a given threshold value of sustained wind speed. If I have the instantaneous values from ...
25
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2answers
27k views

Why are there no hurricanes in the southern Atlantic basin?

We see tropical cyclones (going by different names e.g. hurricane, typhoon, cyclone) all over the tropics, but it seems that there are never any storms in the southern Atlantic. See this map of ...
16
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1answer
373 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)....
9
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1answer
209 views

Monsoonal interactions with mid latitude disturbances

For the past few years in succession India has witnessed extreme flooding events caused by monsoonal troughs colloding with what appears transitory mid latitude disturbances and these appear to ...
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 ...
7
votes
1answer
144 views

Strangely bright morning twilight over Switzerland

Yesterday morning (04.11.2014) I woke up at 6:40 as usual and noticed that it was relatively bright out. I had a better look around 7 and concluded that it was definitely quite a bit brighter than it ...
12
votes
4answers
5k views

How to get cell indices from latitude and longitude in WRF model grids?

I am using Weather Research and Forecasting model WRF and the WRF Preprocessing System WPS and could not get a satisfying answer from wrfhelp. Can anyone guide me in transforming latitude and ...
5
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2answers
297 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
votes
3answers
573 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
votes
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
434 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
250 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
votes
2answers
828 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
votes
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
votes
1answer
692 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
votes
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
votes
3answers
872 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
votes
2answers
683 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
votes
1answer
265 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
845 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
votes
1answer
14k 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
votes
1answer
535 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?
21
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3answers
40k 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
votes
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
votes
1answer
278 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
votes
1answer
95 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
votes
1answer
194 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
662 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
votes
0answers
427 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
votes
2answers
4k 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
votes
1answer
153 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
votes
0answers
134 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
votes
1answer
996 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
votes
1answer
411 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
votes
1answer
729 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
votes
1answer
126 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
851 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
466 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
votes
2answers
3k 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
126 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 ...