Comparison Of 144-Hour Forecasts Valid 00 UTC 27 February

I've shown above: 1) the GFS 144-hour 500 mb forecast valid at 00 UTC 27 February (5 pm MST last evening); 2) the GFS verifying analysis for 00 UTC last evening; 3 and 4) same products for the ECMWF. Again, the ECMWF was considerably better than the GFS with the long-rang forecast (6 days in this case). It should be noted that the GFS quickly became more and more similar to the ECMWF in subsequent forecast runs. The GFS was mostly off in location and orientation of the 500 mb trough over the West; whereas, the ECMWF was quite accurate regarding the position and orientation of the system, but was a tad too slow and also about 50 to 100 m too deep. But, once again, fairly remarkable performance, especially for ECMWF, for a six day forecast. Of course, the details of the sensible weather with the system are much more difficult and were still challenging to forecast within the last 48-hours.