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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12
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2answers
2k views

Can an Atlantic hurricane enter Mediterranean sea?

I can't find any examples, has it just never happened before or is it impossible because of environmental factors?
9
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1answer
676 views

Why are there different vertical gradients of temperature in different layers of the atmosphere?

The temperature of the troposphere decreases with altitude whereas it is opposite in the stratosphere and again fluctuates. Why is this so?
6
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2answers
2k views

How to plot lat-lon-rainfall in MATLAB?

I have average annual rainfall values at few grids, as shown in below example; Lat: 25.5 26.5 33.5 34.5 35.5 36.5 41.5 42.5 Lon: 89.5 91.5 78.5 79.5 83.5 84.5 75.5 76.5 Rain: 110 120 122 135 114 ...
8
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2answers
578 views

How to perform regridding (1.0d to 0.5d) using bilinear interpolation for an irregular area?

I need to regrid temperature dataset from 1 degree to 0.5 degree. In case we have data available for all grids falling in a square, as shown below, we can simply regrid it using bilinear/bicubic ...
7
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2answers
510 views

Dew point variation in a day

Is this true? "If there are no weather front or severe weather systems, then the dew point within a single day is fairly constant, no matter how large the day/night temperature variation."
11
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3answers
318 views

Wind profile below the aerodynamic roughness length

The vertical profile of horizontal windspeed is often given by the so-called "log-law": $$u(z)=(u^*/k)\ln(z/z_0),\ \mathrm{for}\ z>z_0,$$ which can be found here. As can be seen from the ...
4
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0answers
485 views

Explanation of yellow/pinkish sky? [closed]

Last night the sky suddenly went yellow/pinkish colour. It looked like someone placed a transparent yellow/red plastic over our windows. I went outside and everything looked a pink/yellow colour, ...
9
votes
1answer
20k views

Why does it rain more at night than during the day?

I'm living near a sea, and it rains mostly and heavily at night from 11 PM to 3 AM. The weather is mostly clear during daytime. Air is generally cooler at night, and cool air holds less moisture ...
9
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0answers
129 views

Is there a distinction between gap winds and channelled flow?

I have seen gap flows mentioned in the literature, for example [Gohm et al. 2004, Zängl 2002, Mayr et al. 2007]. Whiteman 2000 defines a gap as a "major erosional opening through mountain ranges" and ...
9
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3answers
3k views

What causes clouds to appear blue?

In a thunderstorm cloud about sunset time, I saw these clouds, including some (in the upper right) that were a unique shade of blue. I don't think I've seen clouds quite that color before. I tried ...
10
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1answer
392 views

Explanation for growing circular echo on weather radar?

Does anybody have an explanation for the growing ring/growing circular echo that I occasionally see on weather radar? Attached is a gif of a NEXRAD loop showing areas around Denver, CO, Aug. 2, 2015 3:...
10
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1answer
851 views

How does evapotranspiration affect rainfall?

Evapotranspiration is when a plant evaporates water off the surface of its leaves in order to move water throughout its system with cohesive and adheisiveforces. My question is how will a sudden ...
12
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2answers
9k views

How far away can you see a thunderstorm?

At 9:30 PM on July 13, 2015, I was looking due south from Oshkosh, WI. I saw very clearly a large storm with 1-2 lightning strikes per second. I could see cloud-to-cloud lightning traces, as well as ...
11
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1answer
228 views

How are low pressure zones tracked across the ocean?

When you look at a surface pressure chart e.g.: (from http://www.metoffice.gov.uk/public/weather/surface-pressure/#?tab=surfacePressureColour&fcTime=1437480000) you can see low pressure zones ...
8
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1answer
360 views

What is this cloud formation?

What is the cloud formation in this video? I don't know where this footage was taken. Here's the link to the video again.
10
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1answer
398 views

Optimal vertical coordinate for complex topography

There are plenty of choices in models in so far as choice of vertical coordinate is concerned for meteorological models. Five that I know of: The sigma coordinate system - Hybrid coordinate system(...
10
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2answers
210 views

How do the various types of clouds affect the atmosphere below them in a polluted environment?

I am working through this problem on my own as well, but am feeling that some perspective is in order. So, ignoring the obvious effects where precipitation will wash stuff out of the air, and blocking ...
10
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2answers
335 views

The origin of spurious high frequency waves in numerical weather prediction

I am currently reading this paper on digital filters and their relevance to meteorological models Digital Filter Initialization . My question relates to this following text - "The requirement to ...
21
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2answers
3k views

Is there an upper bound to the amount of rain that can fall in an hour?

The record for most rainfall in a single hour is 12 inches (30.5 cm), set in Holt, Missouri, in 1947. What is the maximum amount of rainfall that could theoretically occur in an hour?
7
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2answers
235 views

Are Southern Hemisphere 'Polar Blasts' caused by global warming?

The SMH journalist writes about a cold snap hitting the East Coast of Australia in July 2015: Proof of the big chill will be the extent of regions across Tasmania, Victoria and NSW experiencing ...
6
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3answers
15k views

What is a temperature inversion and can it trap smog/pollution?

Just as the title says, I heard about this term but am not sure how it works.
4
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1answer
76 views

How can I define frost based on a weather record?

If I want to (programatically, in a plant growth model) define a growing season as last frost in spring to first frost in fall, how might I determine these dates based on a weather record that ...
7
votes
3answers
379 views

Algorithmically Determining the Rainy Season

I have historical precipitation data for hundreds of cities around the world. I would like to algorithmically determine when the rainy season (if exists) is for each location. Are there any algorithms ...
8
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1answer
13k views

How to calculate specific humidity with relative humidity, temperature, and pressure

I know there is this question already How do I convert Relative Humidity into specific humidity but I don't have ρws = density of water vapor (kg/m3) and ρ = density of the moist or humid air (kg/m3)....
9
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1answer
786 views

Evaporation loss formulas

A while ago I created a spreadsheet to calculate evaporation loss. I found several formulas to do that, two from Kevin Rafferty and one from Engineering Toolbox. The one from Engineering Toolbox was ...
3
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2answers
105 views

Why do clouds have areas of darkness instead of scattering light to produce a rainbow?

I suspect it has to do with the difference in size of a rain drop and that of the water particles in the cloud.
6
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1answer
770 views

Specific humidity range in tropical lowlands?

I am running a land biosphere model that uses meteorological data as drivers. The model has a threshold of 32g/kg for specific humidity. The data I am using taken from a reanalysis performed by J. ...
4
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1answer
2k views

How do I convert Relative Humidity into specific humidity [duplicate]

I am using NCEP_DOE reanalysis 2 data set. It include only relative humidity while I need specific humidity. How do I convert the relative humidity into specific humidity?
30
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2answers
42k views

At what humidity does it start to rain?

As far as I understand it is perfectly valid for air to have 100% humidity. At that point, all water can still exist in form of vapor, non-condensed. Does it immediately start to rain if humidity is >...
15
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2answers
1k 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 ...
16
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2answers
3k views

Why do clouds sometimes form a ring around the Sun?

Someone shared a video with me in which clouds were forming a ring around the Sun. I took this screen shot of that video: What is the reason behind this?
5
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1answer
355 views

What is “focus point” in WRF-plots grid box? (python code)

has anyone used the python code from here (written by Geir Arne Waagbo) to plot skewT plot from WRF output? I've got a question regarding some of the functions used in the code found in ...
10
votes
3answers
6k views

What does the notation “kg kg-1” for units mean for specific humidity

I am using a data set from Justin Sheffield at Princeton that includes specific humidity. The description is as follows: "Reanalysis 6-hourly specific humidity interpolated to 1.0deg with account ...
6
votes
1answer
174 views

Eliminating range folding error in doppler radar returns

With weather radar, it's not uncommon to see large areas of the image blocked out due to detected range folding. It's my understanding that this occurs when a reflection outside of range comes back ...
9
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2answers
3k views

Why do certain areas on Earth have a higher or lower air pressure at sea level?

For instance, looking at this map of world air pressure in January and this map of July, why do some land surfaces have a higher pressure during the winter? I know that the tropics and Coriolis ...
10
votes
2answers
665 views

How can daily brightness be quantified or measured?

It occurred to me that there might very will be a metric out there that measures and quantifies "daily brightness". Meaning, how bright any given day is, taking weather conditions and cloud coverage ...
8
votes
2answers
3k views

Are lightning storms more common at night?

I have, to my knowledge, seen far more lightning strikes and heard more thunderclaps at night than I have during the day. Are lightning storms more common at night, or are they just more noticeable ...
7
votes
1answer
880 views

Why do the dry and moist adiabatic lapse rates converge with height?

Near the surface, the slope of the moist adiabats are much steeper than dry adiabats due (as I understand it) to the the latent heat released as water vapour condenses. The difference is amplified at ...
13
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4answers
954 views

How to tell if a single day of weather is an anomaly or due to climate change?

I am interested in understanding how to tell if a single day of 'abnormal' weather is due to climate change or not. From my understanding, you would compare this day's weather to historical weather. ...
11
votes
2answers
176 views

What ice phenomenon are we seeing in this video?

I don't know what this YouTube video shows, but it appears to be half glacier and half "the blob." It almost appears to be "growing" although I assume it's being pushed somehow. Can someone tell me ...
3
votes
1answer
535 views

Why is the colour gradient in the sky at sunset on an angle?

Below is a picture of a typical sunset that I have been observing lately at an undisclosed location in the Southern Hemisphere: Given that the base of the picture is parallel to sea level, you can ...
1
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1answer
123 views

Tornadoes meeting with an Immovable, Unbreakable, Large Cube

What would happen to a tornado if a Large, Immovable, Unbreakable and Obsidian Cube was in its path? The tornado is on a flat plain... but is heading towards the cube. By large, I mean the length of ...
10
votes
1answer
3k views

Wet and dry seasons - what are they and how do they form?

While asking questions on Worldbuilding, I keep hearing about wet/dry seasons. Obviously, one has rain and the other doesn't, and I've gathered that they occur with regularity on an annual basis, but ...
4
votes
1answer
574 views

How and why humidity and vapour pressure change as a parcel of air with an unchanging amount of water vapor rises, expands, and cools

I know that a parcel of air can rise, cool and create clouds and rain but I'm struggling to understand how: absolute humidity relative humidity actual vapour pressure saturation vapour pressure ...
7
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1answer
69 views

How big is the influence of tree leaves on global windsystems?

As anybody knows, there are a lot of forests. I stumbled upon the question whether these have any effect on the global wind-systems. Imagine the following situation. All trees suddenly die in an ...
24
votes
7answers
25k views

Is a complete global flood physically possible on Earth?

Genesis 7:11-20 presents an account of a precipitation event which, in 40 days, submerges the entire surface of the earth: [On] the seventeenth day of the second month — on that day all the ...
6
votes
4answers
1k views

Does “wind” include the air molecules involved, or merely the kinetic energy?

This question is about a riddle in which the statement "I am weightless" was made, and the answer was "wind". I want to know, by definition, does the wind include the air being moved, and thus have a ...
5
votes
1answer
145 views

How does high rate of evapo-transpiration contribute to the ineffectiveness of rainfall?

If evapo-transpiration is high then more water vapor is taken up to the atmosphere and more condensation takes place resulting in more rainfall. But in the book The Environment of Pakistan by Huma Naz ...
5
votes
1answer
89 views

Where can I find solar radiation data for specific land areas?

NOAA has solar radiation data for 1991-2010 http://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/solar-radiation But I need data for Nov 1 2012-present! Is this data ...
9
votes
1answer
157 views

Dependence of solar irradiation through the atmosphere on Sun's altitude

I want to show that the higher the Sun's altitude, the higher the solar irradiation through the atmosphere, through simple experiments. However, I don't have the instrument that measures irradiation. ...