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Cali has been dry for the last 20 years. Just more proof a rapid warming planet will change weather patterns in the south first and within 30 more years effect places to the north more and more as we see less and less rain in FL and get more freak rain events like we saw in 2015,16 and 17.
The North Pacific High and the California current which brings cold water down the coast from Alaska, keeping the water temps too cool for convection and even creating an inversion where the mountains get warmer than the coastal plain
Which one out of them has a bigger role in making California dry?
CA is dry until it's not. When it gets a big El Nino event it's not uncommon for SF or Sacramento to see 10" of rain a month during the winter. During those times, reservoirs can literally climb 50' in a matter of a week.
This is not the Desert Southwest. It's a Mediterranean climate so a dry summer is normal. You have to look at the winter rains and how much they come down. Sometimes they can be severe. Look at Redding's climate. More rain than many places east of the Rockies but concentrated in only about 9 months of the year.
Many people visit CA in the summer and see the brown hills and think "Man this place is dry" but if they would come in the winter they'd see green hills and think "Man this looks like Ireland."
yeah, but why does the sierra nevada itself not get as cold as the midwest? ive noticed that even southern illinois or missouri can be colder in the winter. eastern california, to the east of sierra nevada, is supposed to get colder, due to a cold air pocket landing in the winter.
As the Earth spins, air masses move with it. In the midlatitudes, air masses move from west to east. So the western United States receives air masses off the Pacific. By the time this air has reached the Midwest and East Coast it has become continental air — much more extreme than mild oceanic air. Once it gets to the Atlantic it begins to modify and become mild oceanic air again, but way offshore of eastern North America. It then hits Western Europe as a mild oceanic airmass again, then moves across the huge Eurasian continent and becomes continental (extreme) east of the Mediterranean, Black, and Caspian seas. By the time it reaches the east coast of Eurasia the air is extremely continental again. Very cold in the winter, hot in the summer. Then it moves into the Pacific and begins to take on mild characteristics again as it heads toward...California.
Btw in North America, if arctic air masses sink south, they usually get caught up in this flow from the west and therefore curve off toward the east. Any cold air that does make it to the west coast is rapidly modified by the westerlies bringing mild oceanic ashore.
yeah, but why does the sierra nevada itself not get as cold as the midwest? ive noticed that even southern illinois or missouri can be colder in the winter. eastern california, to the east of sierra nevada, is supposed to get colder, due to a cold air pocket landing in the winter.
Because in the Winter, the jet stream dips lower over the middle of the country and pulls arctic air down from the north.
Location: Live:Downtown Phoenix, AZ/Work:Greater Los Angeles, CA
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Quote:
Originally Posted by Zymer
Because in the Winter, the jet stream dips lower over the middle of the country and pulls arctic air down from the north.
We get troughs in the west too, but unlike the Eastern 2/3rds of the country, we have the Rockies blocking out Arctic air when we get troughs (cold air sinks, and doesn't cross 10,000ft plus mountains). So our cold air comes from the Gulf of Alaska, which is much warmer than the Arctic Ocean
We get troughs in the west too, but unlike the Eastern 2/3rds of the country, we have the Rockies blocking out Arctic air when we get troughs (cold air sinks, and doesn't cross 10,000ft plus mountains). So our cold air comes from the Gulf of Alaska, which is much warmer than the Arctic Ocean
This is totally false. Read my post above.
The Rockies block mild air from moving east. They don't block cold air from moving west, because air masses don't move from east to west in the midlatitudes. When that abnormal east-to-west flow does occur on the west coast, it's called "outflow winds" and the mountains don't block the cold air at all, they actually enhance it.
Edit: Look at Europe. No mountains blocking the flow from west to east, so cold air doesn't build up in the interior of Western Europe, and never gets a chance to funnel to the coast. The mountains don't make our west coast warmer, if anything they make it colder. Cold air masses can build up on the other side and spill over during outflow conditions, being funneled through valleys to the coast. that doesn't happen in Europe.
Location: Live:Downtown Phoenix, AZ/Work:Greater Los Angeles, CA
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Quote:
Originally Posted by unobtainium
This is totally false. Read my post above.
The Rockies block mild air from moving east. They don't block cold air from moving west, because air masses don't move from east to west in the midlatitudes. When that abnormal east-to-west flow does occur on the west coast, it's called "outflow winds" and the mountains don't block the cold air at all, they actually enhance it.
Edit: Look at Europe. No mountains blocking the flow from west to east, so cold air doesn't build up in the interior of Western Europe, and never gets a chance to funnel to the coast. The mountains don't make our west coast warmer, if anything they make it colder. Cold air masses can build up on the other side and spill over during outflow conditions, being funneled through valleys to the coast. that doesn't happen in Europe.
I'm not wrong
Arctic air masses flow from north to south, you have oversimplified the typical east west dynamics.
Denver on the east slopes of the Rockies gets its coldest/snowiest air masses when winds blow from the southeast, usually when a low pressure system is to the south of them over OK/TX. When Denver gets west winds, they're in a Chinook pattern, giving them a downsloping katabatic wind. And we here in Phoenix get some of our warmest air masses when winds blow from the northeast or east for the same reason, downsloping katabatic wind.
Arctic air masses flow from north to south, you have oversimplified the typical east west dynamics.
Denver on the east slopes of the Rockies gets its coldest/snowiest air masses when winds blow from the southeast, usually when a low pressure system is to the south of them over OK/TX. When Denver gets west winds, they're in a Chinook pattern, giving them a downsloping katabatic wind. And we here in Phoenix get some of our warmest air masses when winds blow from the northeast or east for the same reason, downsloping katabatic wind.
The part where you said
Quote:
We get troughs in the west too, but unlike the Eastern 2/3rds of the country, we have the Rockies blocking out Arctic air when we get troughs (cold air sinks, and doesn't cross 10,000ft plus mountains).
is false. The Rocky Mountains don't block arctic air from reaching the west coast. And most importantly (to answer the OPs original question), the Rockies are not the reason for the west coast's mildness compared to the east. That is entirely due to atmospheric flow (west to east) which brings mild oceanic air masses onto the west coasts of continents. It also moderates any arctic air that does reach western coasts.
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