While I don’t see a return of winter weather to the region, we do have some possible storms moving back to the region as we head to the weekend. A weak low pressure center will approach the California coast, initially drawing up a warm southerly flow that will result in high temperatures in the 80s Wednesday and Thursday, along with a chance of some afternoon thunderstorms, mainly on Thursday. After a bit of a break on Friday, the low itself moves onshore Saturday and Sunday, dropping our highs back into the 60s with a chance of showers and isolated thunderstorms.

So why are nosebleeds more common here in the winter than the summer? The air in the winter months is generally much drier than during the summer. Colder air typically doesn’t contain as much water vapor as warm air. The dew point can never be greater than the temperature, and if the temperatures are lower, so are the dewpoints. When you take air that is cold and dry (outside) and heat it up (inside) then the relative humidity gets even lower. That very dry air is irritating to the nasal passages, and that is the reason for the nosebleeds.

We have one last weak storm system to pass through the region before we finally get to enjoy some warm spring temperatures. A cold front will move through the Reno area early Thursday morning, bringing scattered rain or snow showers (with little to no accumulations). High temperatures will be in the mid-50s. Skies will clear on Friday and high temperatures will rise to the 70s.

Bob asks: “Theoretically, if a vehicle travelling at night with its headlights on were to approach the speed of light, what would happen to the light beam? If it was already travelling at the speed of light and then turned on the headlights, would there even be a beam of light or would the headlamps just glow? As you can see, I’ve got way too much time on my hands.”

Bob asks the question that has been posed many times before, and as they say, the answer is “relative.” Once you approach the speed of light, time starts to change, and that then changes the definition of “speed”. But let’s for the sake of argument pretend you get your Chevy up to the speed of light (using up more energy than there is in the universe, but we’ll ignore that for now.) What happens? I’ll tackle that tomorrow.

We have a fairly weak storm to get through before the weekend arrives. Starting Wednesday, clouds will increase with the approach of a splitting storm system. Our best chance of getting any precipitation is probably Thursday morning. The mountains could see a few inches of snowfall. Temperatures will remain in the 50s through Thursday in the valley.

After the storm passes temperatures will rebound quickly, climbing into the 60s on Friday and continuing well into the 70s through the weekend.

Yesterday I mentioned that Easter always falls on the Sunday following Passover. Passover falls on the day of the first full moon following the spring equinox. In an effort to get all the churches celebrating Easter on the same day (among other things), the Roman Emperor Constantine I convened the Nicene Council in AD 325. The upshot was a declaration that Easter would be observed on the first Sunday on or after the first full moon after the spring equinox (or the fall equinox in the southern hemisphere.) So if you ever want to figure out when Easter will fall in the future, get out your lunar calendar. It can occur anytime between March 22 and April 25. (Next year is April 21… almost as late as it gets.)

We are starting off with a very nice weekend, with sunny skies and warm temperatures on Saturday. Light morning winds will give way to some afternoon breezes and we should reach 70 degrees at the airport. High clouds will start to move in throughout Saturday night and thicken up Sunday ahead of the next cold front, kicking up some strong Sunday afternoon winds and bringing a chance of late day rain showers. The cold front moves in Sunday night dropping snow levels back to the valley floor by sunrise Monday morning, and a light dusting of snow could have moderate impacts on the commute, but the mountains are likely to see significant snow. An additional storm mid-week will keep temperatures cool throughout.

So how strong a wind at sea level would equal the force of a 100 mph wind at our elevation?

The formula for force of a wind is: Force (lbs/square foot) = (wind speed)² X (.0027).  The .0027 is a fudge factor that works at sea level. The .0027 factor has to be reduced to 15% less at our altitude (.002295). Plugged in, that makes a 100 mph wind here equal to a 92 mph wind at sea level. This can work for any elevation, but you need to adjust the .0027 fudge factor by the percentage of atmosphere you have left. At 10,000’ elevation you have 30% less air, which when plugged back into the equation makes the force of a 100 mph wind equivalent to 83 mph at sea level.

We have one quick shot of wintry weather Wednesday night, and it will leave behind a sold Thursday. The mountains could wake up to between 2-12 inches of snow depending on specific location, while the valleys could still see a few snow showers overnight, any accumulations of any note will likely be confined to the foothills.

Thursday itself will be chilly but dry, with the high temperature dropping to the mid to upper 40s. Friday will bring sunny skies with highs back into the upper 50s which will then climb to9 the upper 60s on Saturday.

The next cold storm will move through the region late Sunday into Monday, with a chance of snow returning to the region.

Nate asked: “I’ve often wondered why we don’t get more damage than we do when we get these strong winds. Perhaps the air density at this altitude makes comparable velocities less damaging than at lower altitudes. If that is the case, is there a method to calculate the actual force or perhaps differentiate damage from a 100 mph wind at sea level and at 5000 ft. elevation?”

There is, and I’ll tell you more tomorrow.