Questions tagged [weather-forecasting]

Questions about the application of weather data in meteorology/forecasting.

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Do geographic features like large lakes or a moraine make it more difficult to predict precipitation?

I've noticed that Environment Canada's precipitation forecasts for the Great Lakes region (east of Toronto) are usually one of the following: 30% rain 40% rain 60% rain 70% rain But not usually ...
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3 votes
1 answer
1k views

What is a wind chill formula that will work from -10 C to +50 C and uses wind speed in km/h?

I'm looking for a wind chill formula that will work from -10 °C to +50 °C and uses wind speed in km/h so that I can use this formula to add this element to a weather station I am programming. I don't ...
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2 votes
0 answers
35 views

Predicting the weather with temperature and humidity

I basically want to make this same idea: Weather forecast based on pressure, temperature and humidity only (for implementation in Arduino) without the pressure sensor. I have a DS18B20 and a HR202 to ...
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0 votes
0 answers
29 views

How to translate irradiance measurements from MERRA-2 datasets to GHI, DNI and DHI?

can someone help me make sense of the MERRA2_400.tavg1_2d_rad_ datasets? I want to know the global horizontal irradiance (GHI), the direct normal irradiance (DNI) and the diffuse horizontal irradiance ...
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0 votes
1 answer
50 views

Where can I find archived NAM/HRRR model runs?

I am looking for archived model runs for high-resolution North American weather models, i.e. NAM and HRRR stretching back 10+ years. Do these exist on the internet? Failing that, what's the next best ...
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3 votes
0 answers
98 views

How much does a global model's accuracy change with the timestep?

I've been working with ICON, ICON-EU and GFS forecasts, and it seems like the temperature results are "close" for the same location, 6 hour forecasts and 120 hour forecasts - MAE: 5.7 and 6....
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1 vote
2 answers
81 views

Tornado prediction or forecasting by supercomputers [closed]

Can tornadoes be predicted or forecasted using supercomputers?
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2 votes
1 answer
198 views

Standard day and night hours in weather reports

Yesterday I saw these day and night average temperature forecasts in my local TV weather report (see image below). I kept wondering if there are 'standard day hours' and 'standard night hours' for ...
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0 votes
0 answers
26 views

How to best calculate ensemble spread with 2D data?

Sorry if this has been asked before, but I am looking through papers and websites and cannot find something satisfying. Say that I have 10 different ensemble members calculating geopotential height ...
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10 votes
1 answer
131 views

How to statistically downscale wind speeds?

Background I am trying to estimate wind speeds at a proposed wind farm site using the method described in this paper hyperlink here. The approach is summarized in figure 2 of the paper. Short Summary, ...
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5 votes
1 answer
49 views

Why does the magnitude of the uncertainty on temperature forecast fluctuate periodically

I remember several years ago, the weather report on the VRT (Flemish national media) would show the temperature forecast of the coming days and it would also show the uncertainty on that temperature. ...
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3 votes
1 answer
81 views

What meteorological features accompany/cause a thermal inversion?

I am physics grad student working on a problem of making a statistical (neural network) prediction of the air pollution in a city. I am provided with hourly values for ca. a dozen meteo features of ...
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3 votes
1 answer
96 views

weather forecast data: how to know what to choose

I am interested in weather predictions at 1-day, 1-week and 2-weeks, ideally with a 1-kilometer resolution in various regions around the globe. I am particularly interested in wind speed at 100m. I am ...
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2 votes
1 answer
54 views

Wind monitoring system for a specified region: How should this be done, and with what?

I am unsure if this is the correct place to ask such a question I will give it a go. So, the lab I work in is building a "drone park" to conduct robotics and controls experiments in. This ...
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4 votes
1 answer
68 views

What makes a typhoon suddenly turn by 90 degrees? (e.g. 2021 In-fa/Fabian)

The motion of Typhoon In-fa or Fabian made a hard 90 degree left turn and started heading towards Taiwan, slowed to 5 km/hr before reaching it, then took a hard 90 degree right turn and proceeded ...
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3 votes
2 answers
222 views

Is there a consensus on the "heaviness" of rain?

As part of the home dashboard I am developing, I get information about incoming rain. It is given in mm/min. Is there a consensus on the precipitation rate that is called "light rain", or &...
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7 votes
2 answers
149 views

How is a weather forecast really done?

I am trying to understand the concrete process of how a meteorologist at a weather forecast office produces the different types of weather forecasts. I understand how numerical weather models work, ...
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5 votes
3 answers
238 views

Why are rain weather predictions (apparently) so unreliable still in the year 2021?

A year or so ago, I finally implemented a little mechanism which, every five minutes, fetches weather data from SMHI (Swedish official organization, having kept track of temperatures and stuff since ...
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3 votes
1 answer
103 views

The Pacific Northwest is about to endure the hottest temperatures in recorded history. What is the atmospheric setup causing it?

This is going to blow the July 2009 heat out of the water and into geostationary orbit. Dew points will also be high, between 17-20 Celsius. This goes beyond Arizona-during-the-monsoon-heat and into ...
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4 votes
0 answers
44 views

Why does the current warm spell in the Pacific Northwest include high, thin clouds?

I've noticed this during summers (lived here since birth). Sometimes there will be cloudless blue skies, other times when it gets warm there will be a layer of thin clouds, often with higher humidity ...
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3 votes
1 answer
205 views

How accurate is the National Weather Service 8 to 14 Day Outlook?

I know that the forecast accuracy for individual days decreases exponentially past 7 days. But what about the ensemble forecasts that give you the general trend for the week after next? https://www....
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12 votes
2 answers
453 views

Do wind predictions have confidence scores?

I’m a sailing captain in training and my community members asked about confidence in wind predictions. They were unhappy with the large variation between different wind predictions. The speed and ...
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1 vote
1 answer
110 views

Why are all the variables ( DRY_DEP_FLUX and WET_DEP_FLUX) zero in a wrf model output in all the time steps

I am working on WRF_GHG, I would like to calculate dry and wet deposition in the dry and wet seasons for CO2 and CH4 gases. However, when I check the wrf output, I see that all the variables (...
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1 vote
1 answer
39 views

Is there any open source, stochastic rain forecast data available for the UK?

I'm sometimes frustrated by publicly available precipitation forecasts, such as those offered by the Met Office or Google. If I understand these forecasts correctly, they tell me: The expected volume ...
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4 votes
1 answer
78 views

Some website or institute with integrated statistics on forecasting the occurrence of rainbows

I am a lay person in meteorology, maybe this is not the right place for my question, but I would like to ask then. My question is simple: is there a website or institute that has integrated statistics ...
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2 votes
1 answer
239 views

How to find the top level of the planetary boundary layer in WRF?

I am working on WRF_Chem, I would like to calculate the concentration of CO2 just in the Planetary boundary layer(I mean, I want to calculate CO2 from surface to top of PBL).in WRF How can I calculate ...
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3 votes
1 answer
619 views

How big was the eye of the El Reno tornado?

As far as I know, the EF-3 El Reno tornado is by far the largest tornado since meteorologists have started observing them. Tornadoes also have eyes, like hurricanes, but are way too small compared to ...
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0 votes
0 answers
61 views

Why is it so warm in the Pacific Northwest of North America right now - mid April 2021?

Temperatures are 5-7 degrees Celsius above average in southwestern British Columbia, and it's surreal for it to be so warm and sunny when the deciduous trees are still mostly barren.
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1 vote
3 answers
458 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 ...
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1 vote
0 answers
36 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 ...
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5 votes
0 answers
107 views

How to download the GFS 2m Temperature data?

I am attempting to download the 2m temperature forecast from the GFS forecasts archived by AWS's open dataset archive. I am having some issues figuring out the feature name to search for in the file ...
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4 votes
0 answers
62 views

Has a hurricane ever crossed the Atlantic Ocean more than once?

I noticed that Paulette (2020) is still a named storm and is now approaching northern Africa and Spain. It is forecast to begin moving west again in the coming week. Has a hurricane / tropical storm ...
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1 vote
0 answers
48 views

What is the best way to calculate anomaly of meteorological variables with the (GFS/GEFS) forecast

To calculate the anomaly of a variable (temperature, for example) I need the climatology (at least 30 years) of that variable. Which climatology data source should I use? Should I use the "...
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1 vote
0 answers
120 views

If the Isthmus between North & South America did not exist what would happen to the Gulfstream and thus the weather in Western Europe?

Given the differences in temperature, salinity and elevation between the Pacific & Atlantic oceans, what would happen to the Gulf Stream and thus the weather in western Europe and also the eastern ...
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0 votes
1 answer
212 views

Can they still not predict rain even one week in advance?

Every ten minutes, I make an API call to the SMHI's API with the GPS coordinates less than 1 km from here (which cannot possibly matter for accuracy, but does for privacy). SMHI is the Swedish weather ...
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-2 votes
1 answer
149 views

Why do the highest temperature levels occur at midday?

I also see that weather forecast sites show temperatures decreasing starting from 3 to 4 pm, but the thermometer shows that it starts droping at sunset.
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-3 votes
1 answer
98 views

Are rainbows a reaction from earths natural release of gas after a rain? [closed]

In my studies, Ive dropped a limestone or porous stone into water, with salt and sugar. The results where an impressive light show of color flashes. With the Earths natural release of gas, these ...
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3 votes
1 answer
352 views

Are weather changes periodic? (Do the same weather patterns repeat over years?) (Cycles) (Journal paper suggestion)

I am wondering if there is long term (10 year, 7 year, 20 year) periodic patterns Similar to short term seasonal and periodic patterns in weather such as sea/land wind, monsoon, ENSO, ocean sea-saw, ...
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5 votes
1 answer
209 views

How/where is randomness/stochasticity used in weather prediction

I am seeking information on how weather models use randomness (if at all). From what I can gather daily weather forecasting uses partial differential equations with initial and boundary conditions ...
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7 votes
2 answers
110 views

Are airliners sensors used to feed weather prediction models?

Weather balloons, as well as specially prepared aircrafts, are used to retrieve several atmosphere parameters at different altitudes that are latter used to feed mathematical models for weather ...
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4 votes
1 answer
334 views

How do they determine the "feels like" temperatures for weather data?

I'm pulling air temperature and other weather stats from various APIs. There's this concept called "feels like temperature", separate from "actual temperature". Apparently, this is the temperature ...
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2 votes
2 answers
171 views

What is the simplest meteorological model to operate?

For teaching purposes I am looking for an atmospheric model that can be easily installed and the input data can be easily read and prepared. Preferably I would like to run a global low resolution ...
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1 vote
1 answer
78 views

What is the "forecast hour of product"

The NCEP website describes the file naming format of the GFS forecast data. https://www.nco.ncep.noaa.gov/pmb/products/gfs/ What does "forecast hour of product" mean?
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1 vote
1 answer
37 views

Ice Water Content from GFS file

I am working my way through this paper: http://downloads.hindawi.com/journals/amete/2017/8707234.pdf Equations 10 and 11 require the ice water content. I can't find it in the GFS grib2 file ...
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1 vote
0 answers
44 views

Digital alternative to hand analyzed maps

I am a staunch believer in the benefit of hand analyzing maps to get a good feel for the state of the atmosphere before getting into my forecast. With Covid-19 keeping us out of the office, one of the ...
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4 votes
2 answers
76 views

How will air quality, weather and climate improve because of the containment, social distancing and lockdown during the COVID-19 outbreak?

The actions taken to contain the corona-virus epidemic is closing any form of human activities in the world. Schools are closed in most cities of the world, people are told to stay at home and it ...
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9 votes
0 answers
90 views

Was this spherical device used in weather forecasting in the 1960's?

The New York Times obituary Robert M. White, Who Revolutionized Weather Forecasts, Dies at 92 shows the image below. It looks like it might be a model of the Earth but I can't tell for sure. Can the ...
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  • 6,956
5 votes
1 answer
311 views

How to get GHI data from MERRA-2?

Help Requested Does anyone know if MERRA2 contains hourly Global Horizontal Irradiance (GHI) data, or some other measurement which we can use to calculate GHI?, If so, could you please let me know ...
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1 vote
1 answer
81 views

Temperature at 2 m MERRA2

I need MERRA2 data with Temperature at 2m. I'm checking on https://disc.gsfc.nasa.gov/daac-bin/FTPSubset2.pl but I can't find this variable. Suggestions where I can find them? Or anyone that did ...
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7 votes
0 answers
155 views

5G interference with weather observation, a thing already?

The scientific community expressed concern that global 5G would potentially threaten weather forecasts by scrambling frequencies in the microwave spectrum used for water vapor, atmospheric temperature ...
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