What Happened to the Heat?

Mike:

 

What changed the weather this week? For the past 3 or 4 days all the news stations said the temperature would be in the 100’s in the Santa Clara County for 3 to 4 days this week. I was really looking forward to it since the Santa Clara Valley had a very mild summer this year.

 

Let me know…

 

Thanks,

 

Bob McTighe

bob.mctighe@ngc.com

 

 

Unfortunately, for my forecast Monday, the oppressive heat never made it out of the East Bay valleys. 

 

The heat was over the Bay, above 2000 feet, trapped above a layer of cooler stable air provided by the sea-breeze.  A land-breeze at the surface, created by an area of high pressure over the northwest, never materialized over the Bay.  It stayed locked in the Central Valley.  This would have reversed the cooling sea-breeze, allowing the ground to heat, overturn, and bring the warm air down from those levels and transport heat from the Central Valley to the Bay. 

 

The most dangerous aspect of a heat wave is the warm overnight lows.  This keeps homes from cooling at night and creates a warmer starting point each day.  Without the land-breeze, this never happened.    

 

A stronger area of high pressure, over the ocean, overpowered the Great Basin high pressure and kept the sea-breeze intact. 

 

If it’s any consolation, from Sunday through Tuesday our afternoon temperatures did warm 7 – 14° above average everywhere except at the Coast, San Francisco, and Oakland. Since Tuesday morning, the forecast has been accurate.

 

One last thought, the computer models we rely on run every 6 hours.  The forecast can change that quickly.  Even if we aren’t on the air at these times, an updated forecast can be found on our website.     

 

Hope this helps.

 

Mike

Mike Nicco

KGO-TV Morning & Midday Meteorologist

mike.nicco@abc.com