If the earth rotated in the opposite direction, how would the bay area's weather differ?

Question

Specifically in the summer and winter.

Answer 1

This is an interesting question. I also have to assume you are talking about the San Francisco Bay area. First, a quick summary of what I think will be different. If you want to read more, I will follow by my reasons why and it will be long.

For the warm season - much warmer - more wetter - more humid - tropical systems - stronger thunderstorm chances but severe events will increase more significantly east of the bay area. Sea Breeze related activities will be the major weather maker for the normal day.

For the cold Season - warmer on the average with more extreme temperature events - drier - less humid with more offshore events - winds can be strong offshore.

My reasonings...

Mid latitude systems will come in from the east and exit to the west. This will likely have a major impact on the weather as the bay area would be rain shadowed by two mountain ranges...The Sierra Nevada and coastal range. So these winter systems will likely not be the major rain maker. Winter will be drier. Rain will likely occur more often in the summer in the form of showers and thunderstorms.

San Francisco Bay climate will come more strongly under the influence of the sea breeze front that will shift inland during the day. During the warm season...best organized precipitation will be along this sea breeze front in the morning. Then hit and miss showers or thunderstorms after frontal passage. The sea breeze boundary storms will likely be much stronger than the east coast type as dry mountain coming down from the Sierra Nevada will meet up with the moist onshore flow. The boundary may be more of a dry line type in the summer as I am not sure how much temperature difference the boundary will have in the morning. This convergence will likely produce some very strong thunderstorms east of the bay area.

With the Valley being the dry lee side of the 7,000-10,000 mountain range, the Sacramento and San Joaquain river may be just a creek or may not even exist at all. So the delta area will likely be part of valley as the delta Island will not exist. Without the delta, there will be no cool delta breeze, mother nature cooling system for the inland valley region.

The beach area will be more sandy instead of rocky since the ocean current will come up from the south. This southern current will also mean the water will be much warmer. This will bring a threat of tropical systems to to the bay area. I think that these Hurricanes will be, on the average, more powerful than what we see in the gulf and east coast. The same reason why Asia gets those super Typhoons more often...this will likely exist for the west coast as well. The Pacific is a much larger ocean so if the conditions are right, a tropical system will have a much longer body of warm water to work. And with such a large body of water...the tropical westerlies and tropical westerlies waves will need to be monitored closely. One fact is that CA will not have a large body of water to our south like the Gulf of Mexico so the main threat of tropical system will be storms curving up from the southwest. Also any tropical systems from the curving up from the south to southeast will likely be rip apart by the mountains and the strong orographics will strip a lot of the moisture out. There will likely not be a warm belt of water right along the coast like the Gulf Stream due to the shape of the coastline sourh of SF Bay.

Temperature will be hard to say. One major change will be the summer stratus that keeps the bay area cold will likely no longer exist. Currently, the warm season mornings are usually blanket with low clouds and fog that sometimes burn off in the afternoon and return in the evening. Instead...you will likely see mostly clear sunrise with winds starting out offshore from drainage winds. By mid morning, clouds will start to form and build near the coast. A line of rapidly building clouds will form by afternoon if it is unstable. The winds will shift to the west and become breezy. By mid afternooon, winds will be gusty onshore with dark and towering clouds will be to your east.

For the cool season. The seabreeze will likely not be much of a factor except for the winds. Temperature will be difficult to forecast. The bay area will be protected somewhat by the extreme cold air that drop out of Canada into the Midwest and Great Basin. The main reason is that the mountain range will still protect some of those strong shallow arctic express air masses, but a deep cold air masses will likely make it through. If the air cold air comes from the northeast...will it still be still very cold if it needs to flow over the top over the Northern Sierra Nevada and coastal hills? The air will go through some compressional heating like what occurs in the LA Basin with the Santa Ana winds. Difficult to say at this point.

So that is a quick summary of some of the major differences that I can think of. I'm sure I am missing a lot more.

Answer 2

Well if the earth rotated opposite i would imagine this would cause ocean currents to be reversed...and what is now the westerly air flow would be easterly...San Francisco might very well have a climate more like what is along along the east coast now....hard to say for sure, but I'm think it would have hot humid summers and colder winters with more snow...

An interesting line of thought regardless :)

Answer 3

If the earth rotated in the opposite direction,the effect of the coriolis force will also be just opposite .The west coasts of continents will frequently face the fury of the hurricanes and cyclones instead of the east coast of continents which are currenly facing the problem . The sun will rise in the west.

Answer 4

Interesting question.

I don't think it would be like the east coast due to the mountains to the east but the flows would be reversed. I would have to compare it to some of the area east of the Andes in South America. It wouldn't be too pleasant and most likely somewhat desert like but with much colder winters.

Answer 5

The opposite of whatever's happening now.

Answer 6

Well, we would all go flying off into space and the earth would implode so it wouldn't matter. Theoretically, the weather wouldn't be different at all. The sun would rise in the West and set in the East but the exposure would be similar.

Answer 7

I assume you mean the San Francisco Bay?
It would likely be about the same as Rio De Janero.

Answer 8

Interesting question. A thought experiment might be useful:

The geometry of Earth rotating in the opposite direction would be equivalent to an inverted earth rotating in the normal direction. San Francisco is at about 38 North latitude; on an inverted earth, it would be at about 38 South. So, an actual city comparable to the hypothetical San Francisco, similar in latitude and land/sea geometry, might be Buenos Aires, at about 35 South. To first approximation, therefore, the climate of the hypothetical San Francisco might be similar to that of Buenos Aires.

The main drivers of climate differences between the two cities are ocean currents and winds. Ocean currents run mostly clockwise in the N. Hemisphere, bringing cold water to San Francisco, and counter-clockwise in the S. Hemisphere, bringing warm water to Buenos Aires. Prevailing winds in the mid latitudes are from the west in both hemispheres, bringing moist maritime air to San Francisco, and drier continental air to Buenos Aires.

http://www.classzone.com/books/earth_science/terc/content/visualizations/es2401/es2401page01.cfm?chapter_no=visualization

So, for the hypothetical San Francisco, both the currents and prevailing winds would be reversed, and instead of bringing cool water and moist air, they would bring warmer water and drier air. The hypothetical San Francisco would thus have a warmer, sunnier, and drier climate - mildly Mediterranean.

One major difference between the two comparison cities would be tropical weather systems: the Pacific is tropically active and the South Atlantic isn't. With the Pacific circulation reversed, a better comparison city with regards to tropical weather, might be Tokyo, at 36 N. On average, about one tropical storm per year passes near Tokyo. Like Tokyo, San Francisco would be affected by the occasional tropical storm, but most tropical storms would affect areas further south and east.

http://agora.ex.nii.ac.jp/cgi-bin/dt/track_geo.pl?lat=35.689&lon=139.692&radius=150&mt=js&t=0&b=14&lang=en&type=1&size=128

Another unique factor in the weather in the hypothetical San Francisco, would be that the prevailing easterly winds would be moving downhill into San Francisco. Warm katabatic winds would cause San Francisco to be warmer than it would be otherwise, with occasional very hot and dry spells.

http://en.wikipedia.org/wiki/Katabatic_wind

So, with all that in mind, here's my forecast....

Summer: Much warmer than at present: highs in the upper 80's, lows in the upper 60's. More humid and wetter: thunderstorms 5-10 days per month, 3 inches of rain total. Occasional very hot and dry spells. Occasional, but infrequent tropical storm activity, an average of one storm a year, approaching from the southwest.

Winter: Temperatures, on average, slightly warmer than at present, but much more variable: highs in the 50's and 60's, lows in the 40's and 50's. Much sunnier and drier than at present. Fewer rain events, about 1 inch per month. Occasional unseasonably warm and dry spells.

That's my forecast: I hope it's worth at least what you paid for it:)