Fast Storm Thursday…And Managing the Power Grid

A fast moving storm will blow (literally) through the region Thursday, kicking up gusty winds across the region and bringing a quick chance of rain and snow. The cold air behind the front will drop snow levels from over 8,500’ Wednesday night to about the 5,000’ level by early Thursday. There is enough instability in the atmosphere to also bring in a slight chance of a thunderstorm here and there, and snow pellet showers could also occur.

By Friday, the skies should begin to clear out. Brisk north winds will keep temperatures in the 50s, but sunny skies should boost the Saturday high into the upper 60s. Clouds increase on Sunday and we do have a slight chance of some showers Sunday night into Monday.

Power Grid

Managing the electricity needs of a community can be a real challenge. Regional power managers monitor power demand not just locally, but nationally as well. When demand is low, some plants are shut down, or at the very least, reduce production. And power can be moved around the grid, from areas of low demand to those of high. Alternative energy sources can provide another supply, reducing the need for fossil fuel consumption.

 

 

Thursday Storm Before a Mild Weekend…And Some Wind Power Questions…

We have one more storm to come through the region as we head toward the end of this work week, but not before we warm things up on Wednesday. A chilly and unsettled trough of low pressure will approach Wednesday, drawing up a light and warm flow. Look for afternoon highs to reach near 70. Clouds out ahead of the Thursday storm will be seen Wednesday, but conditions will be dry and mild.

When the trough pushes through Thursday, winds will kick up (gusting to 55 mph in the valleys), and a chance of rain and/or snow (likely snow pellets) in the valley occurs, with even a slight chance of seeing an isolated thunderstorm. High temperatures will drop into the lower 50s.

The storm passes through quickly, and temperatures will rebound to the 60s by Saturday and to near 70 by Sunday.

Wind power

Yesterday, Ron assumed the wind needs to blow 20 mph before wind farms can generate electricity, but they will produce at lesser windspeeds, just not as much. But there will be times with inadequate wind to produce electricity. They are not meant to replace all electric production, but to supplement the overall grid. Other sources are needed, and I’ll talk about those tomorrow.

 

Typical Spring Weather…And Some Questions About Wind Power

As is common this time of year, we will bounce around a bit weather-wise this week. Tuesday should bring back mostly sunny skies with a warming trend through Wednesday, with 60s Tuesday climbing to near 70 on Wednesday ahead of the next cold front on Thursday. That front will bring back another round of snow to the mountains with a good chance of rain in the valley…and some snow could come down to near the valley floors because of the convective nature of that pattern. That unsettled pattern could also result in some isolated thunderstorms Thursday.

The good news for the weekend is a ridge of high pressure will build back in time for the weekend, with sunny skies and highs back into the 60s for Saturday and Sunday.

Wind power

Ron had a question about wind power: “What percentage of time will there be adequate wind to effectively supply windmills? I have read that a sustained wind of about 20 MPH is required to produce electricity from a windmill. When wind is low or absent – where will power come from?”

I will need to make one correction to Ron’s premise, and I’ll tackle that tomorrow.

 

 

Saturday Break, Another Round Sunday…And Is It Time To Plant?

We have a bit of a break coming our direction Saturday as the first of a few storms moves through the region. Friday’s storm front will leave behind variable amounts of cloudiness and cool temperatures on Saturday dropping valley highs into the low to mid-50s. On Sunday, the next storm front will move in, bringing mountain snow with a chance of some getting over the mountains, although once again the rain shadow will be pronounced as the flow will strike the mountains head on. Snow levels will rise to about 6,500’ on Sunday which is still below pass level, so be prepared for winter driving conditions. Scattered showers Monday will break up into partly cloudy conditions with temperatures back up into the mid-60s by the middle of the week.

planting

With spring officially beginning this week, there is the temptation to get out in the garden and start throwing plants in the ground. This feeling, usually encouraged by wives, is strengthened after going through a week like we had a week or so ago. But husbands, if you are not ready to drop the remote and pick up the gardening spade yet, I have some ammo for you. Early warm weather does not mean that we have put the cold behind us. In fact, on average, Reno doesn’t have its last hard frost until around the first of May. For the outlying regions, the date is even a little later.

Notice I said “on average”. Some years we are done with freezes by now, and in other years, we are still killing plants well into June. But if you want to be on the safe side, I’d keep the frost-sensitive plants in the greenhouses or windowsills for at least another month.

 

 

“Spring-Winter” Storms

We have a couple of “spring-like winter storms” lined up to come through the region over the next four days. Friday will bring valley rain and mountain snow to the region, enough for a Winter Weather Advisory in the hills around Lake Tahoe. Snow levels will start out below 6,000’, but could rise to just above the lake itself in the afternoon. Accumulations could be anywhere from a few inches at the lake to a foot on the tops. Valley rain will be greater on the west side due to pretty good shadowing along with stiff winds. High temperatures will top out near 60 degrees.

A brief break happens Saturday with variable clouds and a cooler day (mid-50s) before the next storm moves in on Sunday, once again bringing valley rain and mountain snow which will stretch into Monday. Snow levels on that storm could get close to the valley floor, but it’s not likely we will see any accumulations below 5,500’.

After another break Tuesday it looks like another storm is lined up for the mid to late part of next week.

 

Stormy Again… And How Do You Know How Cold A Storm Will Be?

Now that spring has officially started (3:29 am Monday was the time of the vernal equinox) it looks like we will move out of the spring-like weather we had for the last couple of weeks of winter. The storm track will move back down from the north and bring valley rain with high elevation snowfall in the mountains. Tuesday snow levels will range from 7,500-8,000’ on Tuesday and will then lower to about 6,500’ on Wednesday. Snowfall amounts will of course largely depend on elevation, but will range from just trace amounts at lake level to 1-2 feet on the crests above 8,000’.

Thursday will bring a break in the action, and then another storm system moves in late Friday into Saturday, dropping snow levels below lake level with valley rain or snow.

barometer

A couple of days ago, a question was posed wondering if the barometric pressure was more influenced by the location of the low or the coldness of it. Either can be the case. Typically, the deeper the low, the colder the air is in the center… although there are exceptions… after all, hurricanes aren’t exactly known for cold temperatures, but have extremely low pressure in their centers. But winter lows around here are typically cold-core lows, and as a rule they get colder the deeper they are.

500mb

But the path of the low also has a lot to do with our barometric pressure. If the low hits us square on then our pressure will generally drop more than if the storm just gives us a glancing blow. But keep in mind… the lows that you see on the satellite pictures aren’t necessarily the lows that the barometer “feels”. The lows you see spinning in from the ocean are mid and upper-level lows, and typically control the circulation up near the 500 millibar level… about 18,000 feet above sea level. But the barometer measures high and low pressure at ground level, and with our winter storms, the surface lows generally come in ahead of the upper-level lows. In fact, the coldest storms usually have a deep upper-level low positioned right above a strong surface high pressure center.

500-1000

So how can you tell just how cold a storm is likely to be? Let’s review: I mentioned that the coldest storms have a very deep upper-level low coupled with a strong surface high pressure right underneath. If you think of that for a moment, it shows one way to measure how cold a storm will be by looking at the height distance between the 1,000 millibar (mb) and 500 mb surfaces. If you have a strong surface high, you have to go higher above the ground before you reach the 1,000 mb level, and a deep upper level low will cause the 500 mb surface to drop to a lower elevation. The shorter the distance between those two surfaces… the colder the storm is. That 1,000-500 mb thickness is a very important forecasting tool, and is used to help determine snow levels. It’s not a perfect parameter, but is another tool in our satchel to forecast when a storm might turn over from rain to snow.

 

 

 

Stormy Pattern Returns Next Week

It looks like the weather is going to turn back into a stormy pattern for western Nevada and the Sierra Nevada next week, with a chance of some rain coming in over the weekend, but that chance becomes likely once the next work week begins.

For Friday, temperatures pop back up into the mid to upper 70s ahead of a weak to moderate cold front coming through the region on Saturday. We will probably get shadowed out here on this side of the mountains with that storm, but the mountains could see some rain with high elevation (above 8,000’) snowfall. After a break on Sunday, a series of moderate to strong storms move through the west coast, dropping the storm track again and putting us in the bulls-eye. Those storms will get progressively warmer, dropping snow levels down to Lake Tahoe by mid-week, and possibly all the way down to the valley floor by the end of the week. High temperatures will be in the mid-60s through Monday and will fall to the mid-50s Tuesday through Thursday.

 

 

Storms Returning…And What Causes The Barometer To Fall The Most?

I hope you’ve enjoyed the spring-like weather we’ve had of late…because it will likely not last through the weekend. The ridge of high pressure that has given us the near record high temperatures is slowly weakening, and over the next several days clouds breaking over the top of the ridge will transition to a possibility of showers by Saturday. Even with that the temperatures will stay above average (in the 70s) through Friday before falling into the 60s over the weekend. A stronger and colder series of storms will move into the region starting next week, bringing back valley rain and mountain snow.

duck hunters

Sometimes I get a question that just begs to be made public … like this one: “We are two old codgers who have hunted ducks together in the Carson Valley for 61 years. We usually agree on most things, but last month we both noticed that the barometer did not go very low considering the amount of precipitation we had.

“The old codger down the road says that in a warm storm the barometric pressure does not get as low as in a cold pattern. Of course I disagreed saying that the barometric pressure is more affected by the location of the center of the low in respect to our area. Please help us out on this one, and don’t worry duck season is over and our shotguns are empty.”

While I hate to get into the middle of a feud between people who regularly entertain themselves with firearms, tomorrow I’ll try to make them both happy.

 

 

Storms on the Horizon…And What Is Corn Snow? (Final)

Some clouds will make their way to the region over the next several days as our ridge of high pressure flattens enough to allow the tail end of a cold front to bring said clouds to the region, meanwhile keeping rain showers to the north of us. The front will also bring some frisky winds, gusting as high as the mid-30s Wednesday afternoon before backing off Thursday. Temperatures will vary between the mid-70s to upper 60s into the weekend,

Speaking of the weekend, the storm track drops to the south bringing back a slight chance of showers by late Saturday into Sunday, opening the door to more storms next week.

Corn Snow

A reader asked if corn snow was the same as graupel (snow pellets.) As a skier, I always considered corn snow to be snow that had gone through several freeze-thaw cycles, creating a crumbly thin surface layer that’s easier to get an edge on. After researching it a bit, I find that I remembered correctly. Corn snow can initially fall in any state, but only becomes such after several days of thermal cycles. It is a highly prized spring skiing condition, when light fluffy powder conditions become rare.

Corn Snow 1

 

 

Warm and Dry… And Is Corn Snow the Same as Graupel?

While I don’t expect any temperature records to fall this week, after the winter we’ve had, it’s going to seem like it. A west coast ridge of high pressure will keep the storm track to our north, and will keep our temperatures in the 70s and 60s throughout the rest of the week. After a sunny Tuesday (with highs in the mid-70s) a Gulf of Alaska low will make a run at us, but the ridge will keep everything but some clouds from getting into the region. Winds will be fairly light Tuesday before picking us a bit mid-week.

At this point, looking a little further out than I generally like to do, there is some indication that we may get back into a stormy track sometime next week.

graupel

When last we met, we were talking about different types of snow, and snow pellets (graupel) seem to be a favorite. Jeanie asked: “You referred to graupel… is this the same as “corn snow”?  What would be the difference?”

It isn’t the same. One is a type of snow that falls… the other a type of snow after it falls. More on the tomorrow.