Coronavirus And The WeatherAdded : Wednesday at 15:10 If you've been following this like the GFS ► commentary and the output of the global models recently, then it will come as no surprise that the model output is frequently changing far more than usual.
Low pressure systems change track in subsequent runs, rain areas either intensify or fizzle to nothing as the next run comes through.
One such system which the models have struggled with is this on on Easter Sunday :-
The GFS ► has had everything for this system including taking it to the West of the UK, East of the UK and just about everything else. Normally, we would highlight this as a crux in the model output and one which the models will eventually get a handle on. But, at the moment, things are a little different.
The reason is that coronavirus has grounded some 70-80% of commercial airline flights. Not gradually, but pretty much over the space of a few days. This has had a rather interesting effect on numerical weather models.
The reason, is that many commercial airline flights record weather data from the moment they taxi until the moment they land. Airlines such as Qantas, China Southern Airlines, Air France, Austrian Airlines, KLM, British Airways, Finnair, easyJet, Thomas Cook to mention just a few will record atmospheric conditions throughout their flight.
These observations are called AMDAR which stands for Aircraft Meteorological DAta Relay and records the height, pressure, temperature, wind speed, wind direction and humidity of the air at various levels.
The observations start at take off when the planes record weather conditions every 6 seconds up until 90 seconds. Then they switch to recording even 20 seconds until they reach cruising level at which point observe the weather every 3 minutes until they start to descend. When they reach this point, they start recording the weather once again every 60 seconds until landing.
This has two main benefits. The regular reporting on takeoff and approach will give a good idea of the atmospheric profile near airports. The cruising data will then record upper air data in sparse locations where manual observations are impossible.
It's not just aircraft data which is unavailable. A drop in shipping has also meant that observations from the ASAP network has also been affected. These are commercial ships which release weather balloons in the oceans at regular intervals.
Not all is lost though. Satellite observations for winds have been increased, but this still leaves plenty of gaps for upper level humidity as well as temperature profiles.
So, if you see the weather forecasts chopping and changing not just in the short term, but the longer term too over the next few weeks then you can blame coronavirus and the effect on the airline industry.
The sooner we get over this, the sooner life can return to normal and the sooner weather forecasting will start to return to the normal level of accuracy once again.
METEOROLOGIST : MARSH |