Tuesday, November 28, 2017

A Week Out

Edited to add: The latest ECMWF 500 mb 168-hour fcst from 12 UTC below.

Another ECMWF flip-flop, as per Dale's comment below!

Another look at the global model operational, 500 mb forecasts at 168- hours (VT 00 UTC 5 December). I've put the GFS at top (it was better in the last two comparisons I did). The ECMWF is below. The ECMWF forecasts rebuild the 500 mb ridge along the west coast with a vengeance. The GFS ensemble forecasts have three members that are similar to the ECMWF; however, three other members have a strong, closed low around the Arizona/Mexico border. Predictability again appears low after 5 days or so.


  1. Dale Ward10:05 AM

    Hi Bob,
    Been watching the forecasts as well. Hoping for some rain or at least more seasonal temperatures. I agree that predictability appears to be low. The operational GFS and ECMWF forecasts seem to flip flop every 6 to 12 hours. The operational 06Z GFS forecast was favorable for rain in southern AZ, but the latest 12Z is not. The spaghetti plots show large uncertainty. One good thing is that all the GFS ensemble members have a trough like feature over Arizona with below average 500 mb heights by the middle of next week. This would be the first time in quite a while.

  2. Hi Dale - it has been so bad since mid-August, that I can't wait to see something really exciting show up in the progs. Maybe the Winterhaven Festival of Lights will pull a really cold and wet system way down here. Bob