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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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Could the electrical potential difference between the Windward and Leeward sides of a mountain range generate electrical current?

I would like to know if it is possible that the electrical potential difference between the Windward side and the Leeward side of a mountain range, due to a thunderstorm occurring on the Windward side,...
WaterSparkle351's user avatar
1 vote
1 answer
75 views

Combining data with different future climate scenarios

I have climate data for future projection scenarios of the RCP type only (i.e., RCP 4.5 and RCP 8.5) and land cover data for future projection scenarios of the SSP - RCP type (i.e., SSP 2 – RCP 4.5, ...
Marine Régis's user avatar
2 votes
0 answers
43 views

What is this band of reflectivity return caused by?

On the reflectivity scan from TIAH on 20240624 at 2058z, a couple of thunderstorm cells pop up to the West of the radar site. Just beyond these cells, a narrow North-South band of reflectivity return (...
scout_raptor's user avatar
5 votes
2 answers
110 views

Why does it snow in Harbin, China but not in Venice, Italy?

Both cities have the same latitude. Why does it snow in Harbin but not in Venice?
ronald christenkkson's user avatar
1 vote
0 answers
30 views

Up to what radius/distance/area maximum do weather parameters remain constant?

Up to what radius/distance/area maximum do weather parameters remain constant? For example, precipitation is so variable that it can vary even within a few meters, while sunshine durations may not ...
Aditi Khatavkar's user avatar
0 votes
0 answers
37 views

NCEP GFS data products: ANL and FH000

I'm confused with the GFS model data products, presented at NCEP Products Inventory website. There are two types of products for analysis: ANL ("**.anl") and FH000 ("*.f000"). As ...
Outlaw's user avatar
  • 101
2 votes
0 answers
25 views

Does the UV index over a day form a Gaussian?

If you go to a website such as this that shows a plot of the UV index throughout the day, you will see that the plot for each day resembles a Gaussian distribution. Perhaps someone with access to raw ...
Damalone's user avatar
  • 121
4 votes
1 answer
35 views

How does ERA5 reanalysis data deal with wildfires?

I am trying to investigate the likelihood of a fire occuring in the Amazon rainforest based on environmental variables, including ERA5Land data such as temperature, wind speed and relative humidity (...
Universal Property's user avatar
2 votes
0 answers
41 views

Best way to analyze changes in locally triggered convective precipitation? Isolating from MCSs?

I have been analyzing hourly precipitation data from stations X, Y, and Z, spanning from 1980 to 2020. My focus is on understanding the trends and triggers behind the gradual increase in afternoon ...
code_error's user avatar
1 vote
0 answers
7 views

How is cloud column water calculated in GDAS model files?

The question NOAA helpfully provides model outputs from the Global Data Assimilation System (GDAS) for the past 10 days (https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/). Products include ...
unstar782's user avatar
1 vote
0 answers
30 views

Is there some science behind the cloud color of "electric blue"

I do notice that the bottom of thunderheads have a dark grey blue hue(here in the PNW they do where I live and T-storms are not common but they do happen). And many times when I see a cloud bank ...
Mr X's user avatar
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4 votes
1 answer
103 views

What would be the atmospheric pressure if the atmosphere was 2/3 the density of water?

I came across a theory that proposed that earth's atmosphere must have had a density of 660 kg/m^3 during the mesozoic, and the gigantic size the dinosaurs attained on land was only possible due to ...
A.J's user avatar
  • 41
2 votes
0 answers
66 views

Absolute and potential vorticity conservation

The source processes for (vertical) vorticity in the baroclinic vorticity equation are the stretching, tilting and solenoidal terms. I understand that all of these terms go to zero in a barotropic ...
bog creature's user avatar
3 votes
0 answers
67 views

How can friction and Coriolis force balance each other out in the Ekman layer?

In most derivations of the Ekman spiral we begin by assuming a steady state in which only frictional (drag) and Coriolis forces are acting- and then we equate them to get the spiral. I have two issues ...
bog creature's user avatar
0 votes
1 answer
70 views

Weather patterns and national borders

I've been observing weather patterns, especially rain, and to me it looks like there is a correlation with national borders. Of course it is nonsense to think rain clouds stop at national borders to ...
Gyro Gearloose's user avatar
2 votes
1 answer
108 views

Where does snow falling at the polar ice caps originate?

Where did the water originally evaporate when snow falls at the polar and Greenland ice caps? I can think of two ideas: The water mostly evaporates from the nearest ice-free ocean because water ...
Peter A's user avatar
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1 vote
3 answers
107 views

Do tropical cyclones impact climate?

Do tropical cyclones (TCs) have a global impact on climate? Maybe in terms of their impact on air-sea heat or gas fluxes? For example cooling the surface ocean, or enhancing CO2 fluxes? The motivation ...
ouranos's user avatar
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2 votes
0 answers
26 views

Can frictional force be un-aligned with wind direction?

There is a well known solution to Navier-Stokes equations for atmospheric boundary layer according to Ekman (see for instance PalArya's book "Introduction to Micrometeorology" or Holton's &...
MichaelW's user avatar
  • 935
3 votes
0 answers
28 views

How does coastal fog form on the Chilean coast?

When traveling through the northern parts of Chile (La Serena, Antofagasta) during November and December, I noticed a thin layer of coastal fog very close to the coastline. Since this fog was present ...
mu88's user avatar
  • 131
2 votes
1 answer
83 views

2023-2024 El Nino Season 5th Strongest on Record Meaning

I was reading the Press Release of World Meteorological Organization press release that was dated March 5, 2024 and I was curious on what they meant by the sentence "The 2023-24 El Niño season ...
theic_ocean's user avatar
1 vote
0 answers
70 views

What are the current theories on the formation of satellite tornados

I have already searched the web for information on the formation of satellite tornadoes but all the sites say the mechanism is unknown. What are the current leading theories for their formation?
Harrychink's user avatar
1 vote
0 answers
49 views

metpy divergence module array indexing error

i am trying to find out moisture divergence using metpy divergence module and i used qu12=q3b*u3b qv12=q3b*v3b HMD12 = mpcalc.divergence(qu12, qv12) here qu12 ,...
Letitbe's user avatar
  • 41
2 votes
2 answers
98 views

How does the wind transport latent heat?

I'm a meteorology student, and this sentence in my lab book confused me: "Both sensible and latent heat are transferred by winds." I understand how sensible heat could be transported by wind—...
Aubrey's user avatar
  • 23
1 vote
0 answers
26 views

Is this the correct way to extract U and V wind components from NEXRAD weather radar?

I am working with NEXRAD radar data, and I am trying to plot the U and V wind velocity for each point on a grid. There is a channel in the data called "Velocity" described as "A measure ...
scp's user avatar
  • 11
2 votes
1 answer
69 views

Units of meteorological data from the NOAA website

I want to check the precipitation, temperature, and rainfall data of South Asian locations. I downloaded the data from: https://www.ncei.noaa.gov/access/search/data-search/global-hourly?stations=...
Mala Pokhrel's user avatar
1 vote
2 answers
181 views

Explanation of geopotential height

I am currently struggling to really understand geopotential height on a conceptual level. Let's say we look at the geopotential height of 500hPa over Europe, where it is usually around 5.5km. Does it ...
AkariYukari's user avatar
0 votes
0 answers
33 views

How do I know where clouds form from a skew-T diagram?

I should know where clouds form in the atmosphere from the skew-T diagram below. The anwer should be that there is a big stromcloud from a height of 300hPa to 900hPa, but I don't get why. My reasoning ...
stancallewier's user avatar
3 votes
1 answer
71 views

cfgrib does not take the proper variable name

Era5 data for wind ...
Antonio Serrano's user avatar
2 votes
1 answer
66 views

Where can I obtain the raw atmospheric data that weather forecast images are based on?

There is a lot of weather forecast data available online, such as this one https://www.wetter3.de/animation_dt.html But as a student, where do I get according raw GFS data instead of images to do my ...
MichaelW's user avatar
  • 935
3 votes
0 answers
53 views

What is the correct velocity to calculate propagation speed of a Rossby Wave?

Rossby Waves have different phase- and group velocities. For a pure zonal wave with wave number k they are $$v_p=\overline u - \frac{\beta}{k^2}$$ $$v_g=\overline u + \frac{\beta}{k^2}$$ So group ...
MichaelW's user avatar
  • 935
1 vote
2 answers
95 views

How can gaseous abundance in ppm be converted to density?

Consider a measurement of the concentration of a gas such as ozone in Earth's atmosphere in pseudo-units of parts-per-million (ppm). What is needed to convert such a measurement to density of the gas? ...
user900940's user avatar
4 votes
0 answers
90 views

Are clouds aerosol?

I recently came across a science writer's page according to which clouds are liquid water. I pointed out to this author that in reality clouds are made up of a dispersion of water micro-droplets in a ...
gryphys's user avatar
  • 161
3 votes
1 answer
60 views

How Low pressure moves across land

I understand that low pressure systems (like hurricanes), can move across oceans since they are constantly fed by warm air from below. But what is it that enables it to move across land? Especially in ...
Guy's user avatar
  • 51
3 votes
2 answers
418 views

At 100% relative humidity, why does the air still feels dry?

At 100% relative humidity, the dew point temperature is the same as the current temperature. One would probably conclude that water would start condensing on surfaces. But seems that is not always the ...
Koala Yeung's user avatar
2 votes
0 answers
32 views

(topic: dynamic meteorology) Problem understanding a picture from Holton version 2004

I'm studying for an exam and I'm having a problem understanding a picture from book "An Introduction to Dynamic Meteorology" by James R. Holton (fig 6.6 in version 2004). I'm not sure if I ...
zetpokaz's user avatar
1 vote
0 answers
54 views

How do we detect thunderbolts in real time?

When I look at radar data (in Windy for example), and I'm looking into a thunderstorm, I often see thunderbolts appearing in 'real time' on the map. How does that work ? I assume some satellites have ...
Fefe_needs_help's user avatar
3 votes
1 answer
96 views

Why does relative vorticity in spherical coordinates have an extra term as compared to the usual cartesian derivation?

With $u, v$ denoting the components of wind velocity along zonal (x) and meridional (y) direction, atmospheric (relative) vorticity is usually defined by $$\zeta_z = \frac{\partial v}{\partial x} -\...
MichaelW's user avatar
  • 935
2 votes
1 answer
105 views

Drawing the cloud cover bar of Skew-T plot

I'm trying to display cloud cover info by altitude from sounding data in a compact widget of an app for free-flight pilots. It's basically the vertical bar showing different shades of gray according ...
nandilugio's user avatar
1 vote
0 answers
51 views

Water on our planet, where did it come from? [closed]

Water on our planet, where did it come from? A water molecule is created when two atoms of hydrogen combine with one atom of oxygen. W The volume of all water (on our planet) is about 332.5 million ...
farsideofourmoon's user avatar
2 votes
0 answers
41 views

Three cell model of prevailing winds

I understand the Coriolis Effect, but how does that make the rising air cool 1/3 of the way to the poles, as opposed to non rotating Earth?
Guy's user avatar
  • 51
4 votes
0 answers
49 views

Better method to identify seasons in temperature time series?

I'm trying to find a way to automatically detect the start/end of the 4 seasons based on a time series of daily mean temperature. According to this paper summer and winter can be defined as (smoothed) ...
Droid's user avatar
  • 421
1 vote
2 answers
120 views

Why is U used for relative humidity in atmospheric measurement equipments?

RH is the symbol of relative humidity in many textbooks. But, in my experience, U is often used in atmospheric measurements. For example, Vaisala PTU300 means pressure, temperature and humidity. I ...
Oone's user avatar
  • 11
1 vote
0 answers
132 views

Can firecrackers be used to subside thunderstorms due to cumulonimbus clouds

Cumulonimbus clouds are associated with thunderstorms. Firecrackers which go up high in the sky and then burst into glittering show, can such crackers be injected in a cumulonimbus cloud and then ...
lousycoder's user avatar
1 vote
1 answer
316 views

Why are eastern Oregon and southeastern Washington so dry?

Why are eastern Oregon, southeastern Washington and southern Idaho so arid, as compared to the humid and lush western Oregon and Washington? In Oregon and Washington there is quite an abrupt boundary ...
user avatar
4 votes
1 answer
356 views

Why was the flooding in Derna, Libya so catastrophic?

I have watched storm Daniel on the internet while it was in Greece and what I saw was much heavier rain than what came down in Libya. But in Libya, property damage and death toll were much heavier, ...
Gyro Gearloose's user avatar
0 votes
0 answers
142 views

Mass weighted vertical average of stream function in python

I have a netCDF file of stream function (psi) having dimension (latitude, level), level is pressure level. There are 5 pressure levels (700,600,500,400,300 hPa). I need to compute the mass weighted ...
Aman's user avatar
  • 1
2 votes
1 answer
592 views

Dew-point temperature and absolute humidity

I am looking for a reference (e.g. book, peer-reviewed paper) that asserts that absolute humidity is "equivalent" to the dew-point temperature. Such statement should be true, AFAIU. Online, ...
Yair Daon's user avatar
  • 123
2 votes
1 answer
181 views

Why do tropical areas have low air pressure?

From the question Why are pressure levels raised on warm days?, my understanding is that the air pressure at surface level is not affected by temperature, as the mass of the imagined air column stays ...
bigfoot's user avatar
  • 23
3 votes
0 answers
57 views

How to explain "Vacuum Cleaner Effect" for upper level PV anomaly?

In Jonathan Martin's Book "Mid-Latitude Atmospheric Dynamics" there is a chapter dedicated to anomalies of potential vorticity (PV). The scenario shown in the image below depicts a situation,...
MichaelW's user avatar
  • 935
1 vote
0 answers
53 views

How to use 1D function metpy.parcel_profile in ERA5 xarray dataset open with dask

I really need help, I'm working on ERA5 hourly data on pressure levels. I've extracted relative humidity and temperature on several atmospheric pressure levels. I use Metpy's '...
nietreil's user avatar

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