July 4 Weather and Fire Threat

 July Fourth is the most wildfire-prone day of the year, with a massive number of human ignition sources spread across the region.  So please be careful.

Today, Washington will be relatively dry, but eastern Oregon will have some natural fireworks from several thunderstorms.

The current (Friday at 8 AM) radar image shows the rain from the thunderstorms over Oregon (below).

With the lightning strike map at 8 AM indicating a number of strikes at that time (red crosses)

The UW WRF model predicts that the main shower area will move to northern Oregon and Idaho by mid-afternoon.

Why showers over Oregon?  Because of an upper-level trough/low pressure moving through southern Oregon and northern California.

The biggest wildfire threat today is from fireworks igniting dry grass and light vegetation. 

 Below is the map (from USDA Fuelcast) of dry fuel amounts over the region. Plenty of fuel over eastern Washington and Oregon.

And, in fact, there are some grass fires burning now, such as the Apple Acres fire near Wenatchee and the Cold Springs fire south of the Tri-Cities. 

The biggest threat will be where there are both strong winds and dry fuels.   

Below are the forecast surface winds around 8 PM tonight.  As expected, the strongest winds are on the eastern slopes of the Cascades, descending into eastern Washington and Oregon.  

This is where folks will have to be very, very careful

Another threat is from lightning-initiated fires over eastern Oregon, something that happened last year.

In short, be careful today and enjoy the 4th.

Mountain Wave Fest East of the Cascade Crest

 Those living in eastern Washington had quite a treat this afternoon and early evening as an impressive show of mountain wave clouds extended over large portions of the region.

Some of the new wildfire cams really displayed the ethereal beauty of the wave clouds (see below).

Below is a nice visible image this afternoon, with lots of mountain wave clouds downstream of the Cascades.

The wave clouds (also called lenticular clouds) are the result of the greatly increased westerly (from the west) winds that developed last night.  Air from the Pacific was pushed up over the Cascade crest and then oscillated up and down downstream of the terrain (see schematic below).

When the air ascended, clouds formed.

The increased flow over and down the Cascades had another major impact: a major increase in wind energy from eastern Washington (green line below).  Ironically, wind energy is very poor around here when we really need it...during the middle of heat waves. 

____________________________

Want to play tennis but don't know anyone at a comparable skill level?

Someone I know quite well has released a wonderful tennis community application that allows you to find nearby tennis partners.  This community has been flourishing in Los Angeles, and Seattle is next on the list.

A nice way to meet new friends as well.

Check out:   Play Tennis Seattle. 

 
https://www.joinplaytennis.com/seattle