Monday, July 4, 2016

July 4th Weather and the Coolest Early Summer in Years

Looking at the model forecasts for the next week, I was taken aback--it was more reminiscent of middle spring than early summer, with much below normal temperatures and lots of showers.  This is a VERY different situation than last year and the persistent low pressure over the coast is not going anywhere fast.

First, today's weather.   The 8:20 AM radar shows a few showers over Northwest Washington and along the western slopes of the Cascades.  Scattered light showers elsewhere.

 The visible satellite image at 8 AM shows extensive low clouds over the eastern Pacific and western Washington and Oregon.  Classic situation with cool marine air enveloping the region west of the Cascade crest.

The latest forecasts suggest a cool day, with extensive cloudiness breaking up into partly cloudy skies away from terrain.  Here is the UW WRF model precipitation forecast for the three hours ending 11 PM tonight (fireworks time).  A few scattered sprinkles, particularly on the Cascade western slopes.

The weather.com forecast for fireworks time (see below) suggests temperature around 60F with about 15-20% chance of precipitation.   Bring a sweater.

But marginal July 4ths are a tradition in western WA, and usually this is a rapid improvement in the following week.

Not this year.

Here is the forecast upper level chart (500 hPa) for next Saturday morning.  A HUGE low pressure centered east of Vancouver Island.  The jet stream (where the lines are close together) is strong and heading south into Oregon and northern CA. What season is this?

The latest Climate Prediction Center 6-10 day forecast for temperature and precipitation is enough for you to put away the shorts and pull out the sweaters.   Blue cold in the west, while the eastern US is warming

Precipitation?  Wetter than normal over us.

The forecast precipitation for the next 72h is moist enough, with British Columbia, the Rockies, and the northern Cascades getting significant rain.  It is good that Washington State held off from promulgating a drought declination.   And the threat of major wildfires is obviously hugely reduced by this situation.


But the next 72h is amazing, with several inches in the Cascades.


The new normal has switched to the old normal.

No comments:

Post a Comment