Coldest Spring Confirmed with Barbecue Index

Today we are getting a break from the cold (more on this later). But I thought it would be interesting to unearth the old "Barbecue Index"---the number of days we have hit 60F or more this spring (to be exact from March 21st to May 11) at Sea-Tac Airport. This is the kind of rigorous research one expects from the UW!

The answer: the index shows this is the WORST YEAR since record-keeping began at this location with only five days reaching 60F. Here is the plot (courtesy of Neal Johnson of the UW):

Even more irritating to many is the trend of the past 7 years---downward.

A big question is whether we are going into a cold (negative) phase of the Pacific Decadal Oscillation--a natural variation over the eastern Pacific basin (see PDO index below). We were in a cold phase during the fifties to the mid 70s, followed by a warm phase until the early 2000s. But what are we in now? A new cold phase?


Here is an amazing image....it shows the difference (anomaly) between the temperature in the lower atmosphere (850 mb--roughly 5000 ft) and normal (climatology) considering the period from March 15th to May 11th. Very large cold "bulls eye" over the Northwest, while a warm center is found over Texas. Says it all. It also illustrates why you can't talk about global warming my looking at ONE location---we might be cold, while others are warmer than normal.

Many of you are asking about this summer. We are now in a rapidly weakening La Nina and our forecast models indicate a cool period later this weekend into early next week. No major warm ups in sight for next week. This summer we will be in a neutral pattern (neither La Nina nor El Nino) and in any case we have little if any skill for summer predictions. So I can't tell you and neither can anyone else.

But one positive....today we will get into the mid-60s and Saturday will be decent (low 60s with increasing clouds) and generally dry (few showers at most). But Saturday night we head back into serious rain and Sunday will be a loss....cool and wet again. In any case, this is better than droughts and wildfires (Texas), tornadoes (Alabama), or flooding along the Mississippi. Or the extreme snow of the eastern U.S. last winter.

Lets face it, weather is rarely normal, particularly if you look across the entire continent. We need to learn how to better predict it (my field's job) and adapt to it (everyone's job). You don't live in mobile home parks in tornado country if you can help it, nor by a large river that periodically floods.

Another Record Cold Month?

Folks, I don't have good news. During many Mays there is a period of warmth....real warmth...somewhere in the middle of the month followed by a return to clouds and the typical June gloom. But I am not optimistic right now that we will get our warm spell...

To "warm up" this blog, lets start with the temperatures at Sea-Tac the last two weeks as well as the normal highs and lows:Only two days of the last 14 have reached the normal highs, and none have exceeded normal. Today we had a ridge (see upper level map for this afternoon) over us and the clouds finally dissipated during mid-afternoon

....very nice for a while. Here is an educational video of today's clouds. First we start with the low murk coming out of the south, then mid-afternoon it breaks and you can see the large wind shear in the vertical, with westerly winds aloft. Later in the afternoon, high clouds start pushing in aloft and if you look carefully you will see a 22 degree ice cloud halo around the setting sun.



But it won't last. A moderately strong front is bearing down on us and tomorrow will dawn cloudy with rain by midday. Here is the visible satellite image for this afternoon. Very nice front stretching from Vancouver Is. to the the southwest. A large field of low clouds off of California (very typical in spring). You can tell they are low because they don't push past the coastal mountains. Behind the front you can see the speckled instability clouds (open cellular convection in the biz) associated with cold air and a nice little low is spinning around in the Gulf of Alaska.



Now the depressing part.

You see the deep trough over the Gulf of Alaska in the upper level weather map above? Such troughs are associated with low -evel cold air. That trough is going to move south and the settle over the eastern Pacific for a long time. I mean a LONG time. Here are the forecasts for Friday afternoon and Monday morning:

Upper level troughing dominates the entire period! Let me put it diplomatically....this is NOT a warm pattern for us and it will produce highly anomalous cold and precipitation into central and northern CA.

Well, what do my friends in the National Weather Service have to say? Here is the 6 to 10 day temperature forecast probabilities. It is probable that whole West Coast will be colder than normal and northern CA and southern OR WAY colder than normal.



And precipitation for the same period? Do you have to ask?