Heavy haze in CA San Joaquin Valley

Lndwarrior

Lndwarrior

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Gary
Flying today in the San Joaquin Valley a very heavy haze materialized in the early afternoon. Visibility was around 3 to 4 miles in the layer, though I was above it.

The haze layer had a defined top around 3500 AGL.

This was not from smoke.

The surface temps were about 19 deg. C (68 F) the dewpoint spread was 10 deg. C. (50 deg. F). The weather briefing had predicted the haze the night before.

I would like to understand what weather phenomenon caused this haze. With the dewpoint spread at 10 deg. C (19 deg, F) it doesn't seem that condensation would be forming.

The fact that the weather briefing predicted it the night before means this was a weather related phenom. So what caused the haze?
 
What was the altimeter setting?
 
EdFred said:
Ding ding ding.

High pressure just holds all the particulates in place.

Lasts for 3 months out here in **** you country.
Click to expand...

Can you explain this a little more? There was scattered to broken low cloud on the outbound flight across the valley at 10:30 am. On the return flight around 1:30 pm the clouds were gone but have been replaced by this thick grey haze.

Are you saying the high pressure held the moisture in place and it transformed into the haze as a result of the high pressure? I really want to understand this, so thanks for your input.
 
Lndwarrior said:
Can you explain this a little more? There was scattered to broken low cloud on the outbound flight across the valley at 10:30 am. On the return flight around 1:30 pm the clouds were gone but have been replaced by this thick grey haze.

Are you saying the high pressure held the moisture in place and it transformed into the haze as a result of the high pressure? I really want to understand this, so thanks for your input.
Click to expand...

Dust, pollutants, and some condensation will all contribute to haze. Stable high pressure systems lock it in place.
 
EdFred said:
Dust, pollutants, and some condensation will all contribute to haze. Stable high pressure systems lock it in place.
Click to expand...

Yep, especially during garlic season. I love that smell. But, when the dew point spread narrows, you can get ground fog so thick, I've seen inexperience drivers pull over and stop, thinking they're safe on the shoulder of the road. Only the car coming up behind them can't tell they're stopped on the shoulder and end up running into them.

It can be severe clear just a few hundred feet up, but barely any forward visibility on the deck. For about 3 or 4 months out of the year, visibility below 3,500' or so is about 3 miles in haze most of the time.

We've done 0-0 vertical takeoffs from the ramp at NAS Lemoore to launch on a SAR.
 
Out here where we get evaporation of Lake Michigan the haze layer will go to 8000' AGL or more in the summer.
 
Lndwarrior said:
Can you explain this a little more? There was scattered to broken low cloud on the outbound flight across the valley at 10:30 am. On the return flight around 1:30 pm the clouds were gone but have been replaced by this thick grey haze.

Are you saying the high pressure held the moisture in place and it transformed into the haze as a result of the high pressure? I really want to understand this, so thanks for your input.
Click to expand...

Haze is pervasive in the winter in the San Joaquin. The high pressure air mass was stable. So stable that there wasn't enough thermal lift to maintain the morning scattered clouds.

Add in heavily irrigated agriculture, Interstate 5 and industry and the stable air mass in the valley just holds all the particulates and evaporation.
 
GRG55 said:
Haze is pervasive in the winter in the San Joaquin. The high pressure air mass was stable. So stable that there wasn't enough thermal lift to maintain the morning scattered clouds.

Add in heavily irrigated agriculture, Interstate 5 and industry and the stable air mass in the valley just holds all the particulates and evaporation.
Click to expand...

Thank you for the complete explanation!
 
Lived in Merced back in 67-68 . Winters were hazy back then.
One day we went up to Huntington lake to fish the back country for a week end.
It was a bright sunny day . As we wandered up the Mountian I looked back and only saw an ocean of haze. Couldn't see through it to the valley floor. It was that day I made up my mind to move back to Montana .
Friends couldn't believe I would leave a tenured job to move back to Montana .
Best move I ever made. :)
 
I used to live there also, Kptv, but I moved almost two years ago.
There’s was always haze in the winter time, the lawyer was pretty thick.

The air in the valley is the worst in the nation, full of dust, pollen, and the smoke from the forrest fires.
with the lack of rain, the dust from the fields would get stirred up along with everything else.
The air dirty air gets trapped south of bakersfield.
 
I'm not saying ANYTHING about haze! Last time I made fun asking," What's the white stuff?" in a bunch of you all's photos, we get hit with a snow storm:confused::confused::confused:
 
Lawyer.... dooh, stupid auto correct!!
 
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