Can Oregon HAVE high heat + Humidity WITHOUT SW flow?

[WeatherArchive]

Why does Oregon heat so dry and what does it take to have high humidity (with heat) here? I know the Great Basin High has some role in it but how?

 

Oregon seems to ONLY have humid nights when we have warm SW flow such as a cut off low that is stubborn to go thru (which also cuts down the daily highs) so any humidity in Oregon is usually felt at night only while cloudy days ease misery.

 

  In the day time the big time heat is generally dry with humidity dropping (well) below 25% and fire fighters hate it but I love it and wouldn't trade it for anything else.  I have seen summer humidity in western Oregon down in the lower 10s range before a couple times.

 

In the old days lumber mills used to shut down any time the humidity was at the 30% mark or lower for more then 1 hour and people would work at night jobs.   https://news.google.com/newspapers?nid=4pF9x-cDGsoC&dat=19560718&printsec=frontpage&hl=en July 18th 1956 

 

It mentions that logging operations came to an abrupt halt as humidity went below 30% and the mercury edged it's way towards 95F.

 

Here is where it gets to 100F https://news.google.com/newspapers?nid=4pF9x-cDGsoC&dat=19560719&printsec=frontpage&hl=en

 

 

Any good heat wave events to look up that HAD high humidity coupled with it that ISN'T SW flow?

[ShawniganLake]

Why does Oregon heat so dry and what does it take to have high humidity (with heat) here? I know the Great Basin High has some role in it but how?

 

Oregon seems to ONLY have humid nights when we have warm SW flow such as a cut off low that is stubborn to go thru (which also cuts down the daily highs) so any humidity in Oregon is usually felt at night only while cloudy days ease misery.

 

In the day time the big time heat is generally dry with humidity dropping (well) below 25% and fire fighters hate it but I love it and wouldn't trade it for anything else. I have seen summer humidity in western Oregon down in the lower 10s range before a couple times.

 

In the old days lumber mills used to shut down any time the humidity was at the 30% mark or lower for more then 1 hour and people would work at night jobs. https://news.google.com/newspapers?nid=4pF9x-cDGsoC&dat=19560718&printsec=frontpage&hl=en July 18th 1956

 

It mentions that logging operations came to an abrupt halt as humidity went below 30% and the mercury edged it's way towards 95F.

 

Here is where it gets to 100F https://news.google.com/newspapers?nid=4pF9x-cDGsoC&dat=19560719&printsec=frontpage&hl=en

 

 

Any good heat wave events to look up that HAD high humidity coupled with it that ISN'T SW flow?

In BC, logging operations often stop when temps (Celsius) and humidity cross over. So 30C and 30% humidity. 35C/ 35% or 25C and 25% and so on.

[Phil]

I think it's because there's no source region for high humidity available to Oregon due to the clockwise nature of the NPAC circulation (both atmospheric and oceanic) and the descending branch of the Hadley Cell there.

 

The Gulf/SW Atlantic SSTs are the source for humidity east of the Rockies via S/SW flow around the Bermuda High, while the WATL Hadley Cell is less stable/defined and more poleward biased during the summer. Those Gulf/Atlantic waters can hover around 90*F for extended periods of time, and the Gulf Stream certainly helps pump those warm SSTs up the coast.

[WeatherArchive]

Then why do cut off shortwaves  give us humid spikes?  Not humid by your standards but for Oregon we get 60+ nights in those scenarios and stale conditions.   In the winter it gives us mild lows of 45-50 at night.

[WeatherArchive]

I think it's because there's no source region for high humidity available to Oregon due to the clockwise nature of the NPAC circulation (both atmospheric and oceanic) and the descending branch of the Hadley Cell there.

 

The Gulf/SW Atlantic SSTs are the source for humidity east of the Rockies via S/SW flow around the Bermuda High, while the WATL Hadley Cell is less stable/defined and more poleward biased during the summer. Those Gulf/Atlantic waters can hover around 90*F for extended periods of time, and the Gulf Stream certainly helps pump those warm SSTs up the coast.

Is that why January 1950 was so d**n warm for the east coast? https://www.wunderground.com/history/airport/KMRB/1950/1/4/MonthlyHistory.html?&reqdb.zip=&reqdb.magic=&reqdb.wmo=MartinsBurg WV history.   Jan 1950. Was it a hyper Bermuda High the suspect?

 

Highest made it up to 79F and it wasn't a one time spurt.  It reached 70 or higher several times that month with many lows at or over 45F.  Considering the average low is slightly below freezing that's insane!   A 'cool wave' mid month lowered totals but not enough to offset the insane values.

 

The lowest low got down to a chilly 17F that month during one of the (cool waves).

 

Here is a weather circulation review of that month for the USA.  https://docs.lib.noaa.gov/rescue/mwr/078/mwr-078-01-0013.pdf

[Phil]

Is that why January 1950 was so d**n warm for the east coast? https://www.wunderground.com/history/airport/KMRB/1950/1/4/MonthlyHistory.html?&reqdb.zip=&reqdb.magic=&reqdb.wmo=MartinsBurg WV history. Jan 1950. Was it a hyper Bermuda High the suspect?

 

Highest made it up to 79F and it wasn't a one time spurt. It reached 70 or higher several times that month with many lows at or over 45F. Considering the average low is slightly below freezing that's insane! A 'cool wave' mid month lowered totals but not enough to offset the insane values.

 

The lowest low got down to a chilly 17F that month during one of the (cool waves).

 

Here is a weather circulation review of that month for the USA. https://docs.lib.noaa.gov/rescue/mwr/078/mwr-078-01-0013.pdf

Yeah pretty much. Bermuda High/SE Ridge.

 

Average lows are in the low/mid-20s most places here in January, so yeah lows in the mid-40s would be warmer than average highs for those days.

[weatherfan2012]

Yeah pretty much. Bermuda High/SE Ridge.

Average lows are in the low/mid-20s most places here in January, so yeah lows in the mid-40s would be warmer than average highs for those days.

49-50 was a pure suckage winter for the east kind of like this past one a no show pretty much.