Questions tagged [weather-forecasting]

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

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4
votes
1answer
108 views

ISA Model and GFS data

I have a newbie question... I always used the International Standard Atmosphere model whenever I needed to calculate the temperature in a given altitude. It always looked accurate to me... However,...
2
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0answers
300 views

Do U & V vectors differ depending on GRIB layers (wind vs current)?

Essentially I would like to know how current direction "DIR C" and wind direction "WDIR" for gribs is computed. I'm trying to compute some angles from u and v vectors in grib files. My understanding ...
5
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1answer
436 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 ...
14
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1answer
4k views

What is the meaning of -999 degrees Celsius?

I was checking the weather forecast just now, and it is showing that it "feels like -999 °C". I never heard or saw -999 °C before. I searched other weather channels, and they were showing that it ...
6
votes
1answer
166 views

Why do forecast areas on weather.gov appear as twisted squares?

I get my weather forecasts from good ol' NOAA's weather.gov site. On the detailed site weather pages, there's a map that shows the forecast area as a green square (for Boston at least, the square is ...
3
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0answers
340 views

Learn weather forecast

Is there any website for videos/articles that explains how to read maps or other graphics use to make forecast prediction (more advanced than the weather channel please) ? It could be about any ...
2
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1answer
341 views

upper air data(observation) and analysis step for GFS model

Global forecast systems(GFS) gives analysis and forecasts at different time steps. Their main source of input is upper air data which is recorded only twice in a day(observation comes at 00 and 12). ...
2
votes
1answer
360 views

How can I learn to make mesoscale/synoptic analyses of major weather events?

With the tornado outbreak in southern Georgia and northern/central Florida on Sunday that has tragically resulted in significant loss of life, eyes are once again on the weather. I was particularly ...
2
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0answers
48 views

What kind of storm tracks produce snow in the eastern United States?

What storm tracks are favorable for snow in the eastern United States? Articles like this one on a winter storm in the Northeast in 2011 indicate that storm tracks are important in snowfall amounts. ...
5
votes
2answers
283 views

Is there a standardized way to define weather icons based on quantifiable data?

Weather APIs often provide weather icons which symbolize the state of the sky at a given point, or as an average. Is there a standardized way to define what the icon should be, based on quantifiable ...
19
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1answer
1k views

What is this “crystal ball” located at a meteorological station?

I found what looks like a "crystal ball" in a meteorological station in the Vlădeasa mountains (Romania). What is its purpose?
4
votes
1answer
188 views

Global Gridded Daily Temperature (at 2m): difference between GEFS Reforcast and NCEP Reanalysis

I am looking for gridded/raster estimates of daily mean temperature (ideally ambient/at 2 meter) for a public health analysis. Specifically, I want to correlate daily mortality counts with daily mean ...
1
vote
1answer
117 views

How can I implement a visualization of archived convective data from numerical weather models?

I've always found geographic visualizations of surface/mixed-layer CAPE models and other weather data to be incredibly interesting. Here's a map featured by the Capital Weather Gang over at the ...
4
votes
2answers
175 views

Are we changing Earth's weather with global warming?

I think that when the air heats up in the day, the radiation from the ground contributes way more to its heating at altitudes more than 300 meters above the ground than convection currents of air heat ...
6
votes
3answers
372 views

Publicly available data set with ensemble forecasts and observations?

I am looking for a publicly available, easy to download, small data set of ensemble forecasts (or reforecasts), with corresponding observations or reanalysis. We are planning to illustrate some ...
5
votes
1answer
73 views

Can the forecast N+1 days ahead be more certain than the forecast N days ahead?

The Swedish meteorological agency SMHI on its website (NB: freezes Firefox on Linux for me, likely due to plugins, works in Chrome) indicates how certain the forecast for a particular day is. Looking ...
2
votes
2answers
112 views

Global warming and winter temperatures

What causes cold temperatures to move earlier than they usually move? Here in Buffalo the weather was 9 °C. However, everyone had winter coats and hats on. There was no snow, but it was very very ...
4
votes
1answer
130 views

Best sources / methods to find additional cloud information for current weather conditions?

I posted this question on Aviation Stack Exchange here. One of the responses suggested that I post my question on Earth Science Stack Exchange. I need a source that reports necessary current cloud ...
5
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0answers
567 views

Why did the GFS switch to hourly forecasts through hour 120?

About a month ago, the GFS was upgraded. Among other things (like making parallel GFS data available), the upgrade notice said: Include hourly forecasts out to 120 hr Now, this seemed ...
-1
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1answer
234 views

Temperature Fluctuation in a Day

I was looking at the temperature plots in Nashik, India and noticed an intriguing trend. What could explain this trend? [screenshot from WeatherUnderground forecast] Shouldn't the plot be smoother? ...
5
votes
1answer
232 views

What is the difference between the freezing level and 0C isotherm in NOAA's GFS?

I'm playing around with NOAA's GFS forecast data and I see that it contains both a "0C isotherm level" and a "Highest tropospheric freezing level". Could someone tell me the difference between these ...
7
votes
2answers
730 views

Long-term Wind Speed Forecasting: reality or wishful thinking?

I have been studying/working with Wind Energy for a while and, one of my main responsabilities right now is to search for adequate long-term wind speed forecasting models. However, 2 things strike me ...
7
votes
2answers
1k views

Help interpreting a wind rose diagram

Can someone comment on technical explanation of the wind rose attached? I can understand the wind is blowing between WNW & SSW with speed of 7-11 km/h. For frequency of 11-16 km/h its blowing ...
11
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1answer
413 views

What does the term “Snow Interval” mean?

When looking Weather Station readings from the National Weather Service website, what does the term "Snow Interval (inches)" actually mean? 6 hr and 24 hr readings are obvious, but I can't seem to ...
6
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0answers
79 views

Worldwide weather maps database

I am searching for a database (a free one would be great) that would give me, for any chosen rectangular area on earth, historic data about pressure, sea water temperature, wind (including both speed ...
4
votes
2answers
1k views

Historical NWS GFS forecast data

The National Weather Service (NWS) makes the results from its Global Forecast System model (GFS) available for download as GRIB2 files. While accessing current (or recent) forecasts is straight-...
1
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0answers
101 views

Sailing Around the World on a Jet Stream

An ultra light plane can stay in flight up to 2400 km (the World Record) with out an engine using thermal lift. Can a huge kite like airship (not a blimp) be built to indefinitely sail in and out of ...
4
votes
2answers
127 views

Need help understanding variables that relate to meterology terminology

I am working on a project in predicting the weather and I had a few brief questions. I understand that radar works by bouncing waves off of precipitation and measuring reflectivity. I have a variable ...
20
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2answers
3k views

What are the major differences between weather models and climate models?

Some weather models include GFS (Global Forecast System) and NAM (North American Mesoscale Model). Some climate models include CCSM (Community Climate System Model) and the NASA GISS (Goddard ...
4
votes
1answer
234 views

Why is it always rainy in Addis Ababa?

I watch the news and in the weather forecast it's always rainy in central Africa, especially in Addis Ababa. Why is that?
8
votes
1answer
100 views

Are the storm cones introduced by Robert Fitzroy still in use?

In 1860 or so, following the tragic wreck of the Royal Charter with the loss of over 400 lives, storm cones were installed in many UK ports, under the direction of Admiral Fitzroy, head of the ...
5
votes
0answers
100 views

Initial indexes for calculating the Fire Weather Index (in the Canadian Forest Fire Weather Index System)

I am applying the Canadian Fire Weather Index (FWI) on the Forest Fire Warning System of my laboratory. My problem is in calculating the Fine Fuel Moisture Code (FFMC), the Duff Moisture Code (DMC) ...
29
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4answers
4k views

How do weather models work?

We use different weather models all the time, such as the ECMWF and the GFS. These models are simply amazing to me. How do these models work? I know they have to take in various data points - what ...
8
votes
3answers
411 views

Predicting school closures with historical weather prediction data?

I'm interested in predicting when the local schools will be closed due to snow and other winter weather. I have a list of school closure dates and a rough sense of the criteria used to determine the ...
18
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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 ...
11
votes
1answer
2k views

Intuitive explanation of precipitation amount

I'm trying to learn how to make sense of numbers in a forecast. I can interpret temperature and wind speed, but I don't know what to make of rainfall. What does it mean, for a human, that there will ...
7
votes
1answer
819 views

Statistical weather prediction

Assuming I have time evolution of air temperature, air pressure, wind speed, wind direction, relative humidity and cloudiness, how can I predict weather based on this information? I know that high ...
20
votes
1answer
736 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
127 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 ...
11
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2answers
313 views

How do meteorologists grade their past forecasts?

In every professional field, practitioners may come home at the end of the day and say "Yeah! I knocked it out of the park!", or alternatively "Oh, man. Gotta do better tomorrow." What about ...