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Forecast Discussion:
We're still in a very quiet, very warm pattern. It is 87F in Longmont as I type (with beautiful blue skies.)
Figure 1 is the upper air pattern with a southern branch ridge (blue line) under a northern branch ridge (up in to central Canada, covering the central U.S. , but not marked). The atmosphere is sinking gently, compressing, and warming. Warm air aloft is flowing in from the southwest making it harder for storms to form. Figure 2 is the surface map for today - there is just a nice big high pressure system, at the surface, over Colorado.
Tomorrow, a hint of change is showing up out in California and Nevada, but we are still under a big high pressure center and headed above 90F.
The longer range forecast:
Figure 4 shows another cut-off low rolling in from the west by the end of the weekend. This might pull moisture in again and slide cold air, aloft, into place to give us rain and thunderstorms. We 'might' have a stormy Memorial Day.
As is the pattern, when the weather gets quiet, we take a look into the distant future. El Nino models were compared, and that comparison was released a few days ago (May 18th). The oceans are near neutral conditions for the summer with a good chance of El Nino conditions later this year (Figure 5). The seasonal outlook for the summer is out from NOAA (Figure 6). Western Colorado is in the above normal chances for precipitation, eastern Colorado is in equal chances of normal precipitation. Southwest Colorado is strongly expected to be warmer than average for the summer while northeast Colorado is expected to be warmer than average.
