Status: Finalised Material from: Linus


 


Picture

1. Impact

On 18 December northern U.S experienced extreme cold temperatures.

2. Description of the event


The plot below shows temperature observations from around Minneapolis for 18 December 12z from www.ogimet.com .


3. Predictability

  

3.1 Data assimilation

 

3.2 HRES

The plot below shows 2-metre temperature for Minneapolis from observations (black), HRES (red) and Control forecast (blue) from 17 December 00z (solid) and 18 December 00z (dashed).

 2-metre temperature for Minneapolis from observations (black), HRES (red) for the forecast from 12 December.

The plot below shows temperature diagnostics for Minneapolis.

The plot below shows a vertical temperature profile for Minneapolis for 18 Dec+12h.





3.3 ENS

The plot below shows the evolution of 2-metre temperature forecasts for Minneapolis on 18 December 12z for ENS (blue) and HRES (red), with the model climate in red.


The plots below show the EFI and SOT for 2-metre temperature on 18 December.



3.4 Monthly forecasts

The plot below shows verification of monthly forecasts of 2-metre temperature valid 12-18 December.



3.5 Comparison with other centres


4. Experience from general performance/other cases


5. Good and bad aspects of the forecasts for the event


6. Additional material