Short update - 11/5/18

The previous post I did on the 19th of October (if you haven't read it, please do so by clicking here), the satellite image I posted showed the state of the jetstream at that time.  Today, there are major differences.  Here is this afternoons look...



The biggest change is the very strong jetstream that is coming off the Gulf of Alaska and southeast towards the central plains.  Minor disturbances in this strong jet have brought a couple of small rain events to the central plains during the past 4 or 5 days.  It will also be contributing to a possible tornado outbreak across the southeast U.S. later this Monday evening.  The configuration has also allowed for a very cold airmass to build up across the higher latitudes of Canada.

The little red X across southern Alaska appears to be a signal for some amplification that will bring a swath of precipitation across the central U.S. late Wednesday into Thursday, and that would be in the form of snow.  For forecasting purposes, these type of dynamic weather producers get most of their forcing from the wind aloft.  Thus, they have very sharp gradients of nothing to potentially a lot of precipitation. In this case, you probably have already seen forecast graphics of snowfall - but everything I've seen is computer forecast generated.  The point with that is that every time the forecast output is run, the resultant precipitation is all over the board, i.e., the models can't be trusted for specific forecasts!   For the purpose of this blog, go to https://www.weather.gov/ for the most up-to-date NWS forecast.

The configuration of the winds aloft will also contribute to much colder weather for a few days later this week.  If it continues in that configuration, there would also most likely be another very cold shot of cold air the following week.  In the blog I did on the 19th (see above link), I mentioned November being near to above normal on temperatures for the entire month (but that was with very low confidence).  These couple of cold shots (this and next week) will probably knock the average for the month down closer to normal. 

Other than the precipitation this Wed/Thu there is not a lot showing up afterwards, at least for the high plains, through mid-month.  The pattern is still evolving.  I still need time to identify the main areas of forcing of the pattern.  Another 2-3 weeks may be needed for that.