Sunday, July 29, 2012

ECMWF Ensembles' Forecast On Par With Expected Winter Conditions

ECHAMA Precipitation Rate Anomaly

ECHAMF Temperature Forecast Anomaly

The ECMWF Ensemble forecasts for December-January-February (DJF) appears to be the most in line with having a reasonable forecast, over other forecast members of the NMME association. Here's why I chose the ECHAMA and ECHAMF, members of the ECMWF squad.

Ridge over Gulf of Alaska (GOA)
There were some models showing warmer than normal temperatures over Alaska, signifying a high pressure over the area. However, after viewing temperature forecasts on the same members, those members showed above normal precipitation for Alaska, not in line with a high pressure over the Gulf of Alaska. Thus, those members were ruled out.

Ridge over GOA + Cool East US
A ridge over the Gulf of Alaska will lead to cooler than normal conditions over the eastern US. Similarly, a low pressure system over the Gulf of Alaska will bring warmer than normal conditions over the eastern US, as was seen last winter. However, despite a warm Gulf of Alaska, a few members showed a warmer than normal Eastern US, disqualifying their reason into their forecasts.

Wet Conditions over the Eastern US
Due to an incoming El Nino, wetter than normal conditions are expected over the Gulf of Mexico coast as well as the East Coast. One or two members displayed below normal precipitation anomalies over the mentioned areas, practically ignoring the El Nino that will be present come winter-time.

All of that said, I find it probable that if a forecast of the NMME members were to verify, it would be the ECHAMA and ECHAMF forecast maps charted above as described above.



ERN WX said...

Perfect. There it is that WILL be how winter will be. COLD AND SNOWY for lots of us. Andrew, great job!!!!!!!!!!

Anonymous said...

Buggh. Of course the rain will miss Texas :(

Anonymous said...

How does Ohio look to be if this pans out?

Andrew said...

Ohio would probably see below normal precipitation, but that could change if a strong Nor'easter spreads its precipitation far west.