Winter Over? Don't Bet on It!

Bicycling in today, I marveled how spring-like it was.  Mild temperatures well above normal.  The grass is really growing--starting much earlier than normal.  At the UW, I could see large number of bulbs pushing up in the beds.   And it has been warmer than normal for weeks now--take a look at the comparison between Sea-Tacs temps and normal:

The normal high is around 45F and we have been hitting 50F and beyond on a regular basis.  Very good for my lost dog.

The National Weather Service extended forecasts have repeatedly called for a return to normal La Nina conditions--wetter than normal and colder than normal--but it simply has not happened.  However, the latest batch of forecasts from both the U.S. National Weather Service and the European Center for Medium Range Weather Forecasting suggest the possibility for a change to much cooler temperatures.  And in the meantime we will have a period of very little precipitation and even some sun.

The European Center for Medium Range Weather Forecasting (ECMWF) is the gold standard for short and medium range weather prediction.  They have about a day more predictability than the NWS forecast center.  This is completely embarrassing, unnecessary, and a national disgrace.  And a topic for another blog.

My rule is that I don't get too excited until the forecasts get within 120h (Saturday morning)--so here is the 120h forecast from ECMWF for upper level heights (500 hPa) and 850 hPa (roughly 5000 ft) temperature.  Cold air (blue/purple) to our north and a trough just offshore.  This is a threatening pattern for cold/snow.

The forecast for a day later is certainly of concern...cold air is closer, as is the trough.

The NWS model slides the cold air past us to the north...and we are just on the edge in the ECMWF prediction.  The ECMWF ensemble mean forecast (averaging a large number of predictions for the same time) has a very similar pattern.

The bottom line---we have several dry days (guaranteed), but will have to watch the situation carefully this week.  The forecasts are on the edge past Friday.  We could end up with nothing or snowpocalypse.   We will know in two days.

We are still in a La Nina year and remember last year (also La Nina)...warm in January and then we froze over in mid-February.  But also keep in mind we really only have 6 weeks left of winter.  By the end of February, winter is really over in the lowlands.  Snowpack in the mountains can still pile up into early April.