Which U.S. City Has The Most Unpredictable Weather?

[irlinit]

Originally Posted by david0966

The D.C. area is right up there. There are many times in winter where the rain/snow line sets up right in the middle of the metro area. Given the dense population just a matter of a few miles can make a ton of difference. Ice storms can also be a big problem. Often times there is "cold-air damming" which makes forecasting the precip type even trickier. This scenario is when cold air settles in in the lower levels east of the mountains, and often times warm air surges north trapping the cold air at the surface. During the spring and summer months, severe storms often affect the area. Temperatures can fluctuate 30 to 40 degrees from one day to the next.

Which is why D.C is a subtropical paradise

[T. Damon]

It has to be Denver. I was looking at the weather graphics in the NYT yesterday after seeing this post and the record and average temperature range this time of year is just massive; it could be nearly 80°F or -15°F!

We were driving into Denver last year in June from the mountains and it was snowing until about 15 miles outside of the city. The next night we were at Red Rocks seeing a concert in our T-shirts.

[armory]

Originally Posted by Unsettomati

A very interesting crunching of the data from the always-excellent Nate Silver and company at 538.


Which City Has The Most Unpredictable Weather? | FiveThirtyEight

Any on any given day of the week is candidate. A predicted heavy rain/snowstorm can easily be a fluke and often times is, especially here in the mid-Atlantic region.

[reneeh63]

Originally Posted by Ed's Mountain

Do you mean most unpredictable or most changeable?

Good question - to me, changeable is a good proxy for unpredictable....what would be another way to objectively measure it?

[Ed's Mountain]

Originally Posted by reneeh63

Good question - to me, changeable is a good proxy for unpredictable....what would be another way to objectively measure it?

Well the article was referring to predictable in the climatology sense: given a time of year what is the weather likely going to be based on the records from previous years. Essentially this is an exercise in statistics; in this sense then changeable is indeed a good proxy for unpredictable. Areas in the upper midwest, such as Chicago, are changeable (and unpredictable) by this measure whilst Phoenix is less changeable (and more predictable).

However, predictable can also mean how easy is it to generate an accurate forecast for the near future. That is, for a given location and set of initial conditions, how well can the weather be predicted in the next 24, 48, 72 hours or beyond. In this day and age Chicago is quite predictable in this sense--even if the weather is changeable. When was the last time a winter storm hit Chicago with no notice?

I speculate that places in the mountain west, such as Colorado, Wyoming, and Montana, would be rather unpredictable in this sense. This is because the effects of local topography are hard to account for in a forecast model.