Astronomy: Forecast cloud cover - important model charts

ECMWF maps United States
ICON maps United States
ARPEGE maps United States
ACCESS-G maps United States
GEM maps United States

Astronomy: Forecasting Your View of the Sky

When observing the sky in search of stars, planets, meteor showers, or even the rare cases of solar and lunar eclipses, it’s important to consider the weather conditions before you head out. You won’t want to brave the cold or bugs if all you can see is clouds! So how do you forecast whether it will be cloudy or not?

The thumbnails above show the forecast cloud cover across the US for the next hour or so according to several different models. To get more detailed info (zoomed in look at your area of interest, your selected time of interest, etc.) click one of the thumbnails to go to our model viewer where cloud cover is already loaded up. It’s generally a good idea to compare a few different models to see if there’s high or low confidence in the forecast. For the US, the best model is typically the ECMWF though the HRRR and NAM models can do well with smaller scale features.

Cloud coverage NAM and HRRR model

Low clouds NAM Middle clouds NAM High clouds NAM

The benefit to checking the maps is that you can see the forecast cloud cover for your region, instead of just right overhead. Why might that be important? Well none of the weather models are perfect. Say there’s a storm moving by to your south. The model might not think there will be any clouds at your location, but with the maps you’d be able to see that clouds are lurking not that far away. If the model was a little off on the storm track, then you could end up seeing overcast instead of clear skies. The spatial context is important when looking at cloud forecasts.

Point forecasts - simple but not always as accurate

If you just want to see the forecast for your town, you can type its name in here. The upside to this is the simplicity of the data readout - it only takes one glance to see exactly what the model thinks is going to happen at exactly your location. However as I mentioned above, the spatial context is often important to cloud forecasts so be sure to look at the maps in addition to the graphs for your specific town.

What about the next couple hours?

If you’re looking for the short term forecast for a particular cloud that might be blocking your view, satellite imagery will be your best bet. If you animate the satellite imagery, you can tell whether the clouds overhead now are on their way out, or if they are developing further. Additionally, you can also see clouds that might move overhead and block your view of the sky in the near future.

Satellite images during the day

Satellite images day and night

What about precipitation?

Forecast Precipitation, 1h - different models

We have forecast data from a variety of global and regional models that produce forecasts for the United States. The maps below shows the total liquid equivalent precipitation expected by the model over a period of one hour. To get more detailed info (zoomed in look at your area of interest, your selected time of interest, etc.) click one of the thumbnails to go to our model viewer where precipitation, 1h is already loaded up.

HRRR maps United States
NAM maps United States
ICON maps United States
ECMWF maps United States
GFS maps United States