Windstorm Update: Could This Be a Big Fizzle over Puget Sound?

There are some forecasts where the uncertainties are very large and this is one of them.  There has been a lot of press about the Sunday forecast, such as the Seattle Times headline below:

The National Weather Service has a high wind warning up right now.  Not a watch.  That means they are very sure that very strong winds are imminent.

But I am very worried about this forecast.  First, the storm hasn't even formed yet.    Here is the latest infrared satellite imagery (8:15 PM)....no circulation or really anything apparent over the eastern Pacific,

And the latest model runs are really pulling back the threat for the Puget Sound interior.

Let me illustrate. The UW WRF forecast for 8 AM Sunday (remember we will be shifting to Daylight Savings Time) is much less threatening:  the low is not as deep and is more amorphous.

 At 2 PM it is stronger, but the pressure gradients are weaker than earlier runs and the low is in a dumb bell shape, which works against really strong winds.  Windy on the southern WA coast at this time (gusts to 40-50 mph perhaps).

The low lifts over southern Vancouver Island at 5 PM, with the pressure gradients over Puget Sound not that strong.  Yes, it will get blustery during the latter afternoon, but we are talking about 30-40 mph gusts, NOT the 60-70 mph gusts being advertised.  Thus, we are talking about a relatively tame event.

So we start with a system in which the solutions are not stable...not good.

 Now lets take a looks at the NWS Short Range Ensemble Forecasting (SREF) System, which uses many model runs (see below).  Oh-oh.  The models are ALL OVER THE PLACE, with some providing very little wind tomorrow afternoon/evening (00-14th is tomorrow at 5 PM).  The strong wind simulations are outliers and the mean of the ensembles is only 15 knots (sustained wind).

The other major NOAA/NWS ensemble is the GEFS ensemble, and it shows a mean sustained wind at 14 knots, with lots of spread of the solutions

Bottom line: really strong winds over Puget Sound is no sure thing.  I suspect that tomorrow will be a tamer version of this week's wind event and nothing exceptional.   But there is considerable uncertainty and there is perhaps at 10-25% chance this will be a notable event.     About the same probability of Marco Rubio winning the Florida primary.

Announcement: Public Talk: Weather Forecasting: From Superstition to Supercomputers

I will be giving a talk on March 16th at 7:30 PM in Kane Hall on the UW campus on the history, science, and technology of weather forecasting as a fundraiser for KPLU. I will give you an insider's view of the amazing story of of weather forecasting's evolution from folk wisdom to a quantitative science using supercomputers. General admission tickets are $25.00, with higher priced reserved seating and VIP tickets (including dinner) available. If you are interested in purchasing tickets, you can sign up here