Tag: earthquakes

Watching the Weather

Dark stormy sky over our hoophouse and solar panels. Photo Wren Vile

Farmers and gardeners have always watched the weather, and now, as the climate crisis gets worse and the weather more chaotic, we need to hone our skills. I’ve written in the past about

Where does your weather come from?

Our mid-Atlantic weather mostly comes from one of three directions,

  • mainly from the Gulf of Mexico, (wet, maybe windy)
  • the Bermuda High Pressure area in summer, (hot and dry)
  • recurrent waves of cold air from Canada in winter (from a disrupted polar vortex).
  • Due to the erratic movement of thunderstorms, some parts of our area may experience long periods of drought. September–November is the dry season but also the hurricane season.
Such grey weather! But will it rain?
Photo Wren Vile

Find a weather station that is a good match for your area, and learn how to adapt it

We use Wunderground.com for Louisa Northside, but subtract 5F° from their forecast night lows, and mentally downgrade the chance of rain by 10%, as rain often passes us by as it scoots along the river valley north of us. I use the ten-day forecast to get the general idea, the hourly one when planning tasks, the Roanoke animated radar on the daily page to see what’s on the way and when it’s likely to arrive, and the alerts, watches and warnings. The forecast for the month is under the Calendar tab, although the further out the forecast is, the less reliable it will be. In hurricane season I check the Severe Weather tab with the Hurricane and Tropical Cyclones information.

Make yourself a Frost Alert Card of conditions that are likely to lead to an early or late frost, so you can quickly take avoiding actions without dithering.

Learn about recent average weather at your location.

I recommend Weather Spark for browsing on a rainy day, or a too-hot afternoon. “The weather year round anywhere on earth”

Weather Spark chart of average daily temperatures in Louisa County, Virginia

I rechecked our area on Weather Spark recently and realized how much has changed since I started quoted information from our Extension Service twenty or more years ago.

  • The climate in Louisa County, Virginia, is changing on average in the past ten years to drier weather with milder winters, hotter summer nights.
  • Twin Oaks is in USDA Winter Hardiness Zone 7a: the average annual minimum winter temperature is 0°F–5°F (–18°C to –15°C).
  • The average rainfall for a year is 37” (100 cm), fairly evenly distributed throughout the year, at 2.2”–3.6” (5.6-9.1 cm) per month. October is the driest, May the wettest.
  • The average daily maximum temperatures are 49°F (9.4°C) in December and January, 89°F (31.7°C) in July. The average night low temperatures are 29°F (–1.7°C) in January, 69°F (20.5°C) in July.
  • The season from last frost to first frost, is around 211 days. The average date of the last spring frost is April 24 (later than May 7 only happens one year in ten); the average date of the first fall frost is Oct 14 (earlier than Oct 1 only happens one year in ten).

Weather SparkOn Weather Spark you can study artfully-made colorful charts of temperature, precipitation, cloud coverage, humidity and tourists (!) month by month. There is a chart of average high and low temperatures over the year, and one showing the average hourly temperature over the year (we are currently in the big red blob of hot afternoons). There’s a grey and blue chart of cloud coverage, and a green one of the daily chance of rain (with touches of blue and purple frozen precipitation). The average monthly rainfall chart is all greys, as is the snowfall one. Our greatest chance of snow is February with an average of 4.2” for the month.

You can compare your nearest city to another you might dream of moving to.

There are charts of hours of daylight and twilight, sunrise and sunset, the solar elevation and azimuth (for those planning greenhouses); moon rise, set and phases for a choice of years; and – oh – humidity! Color-coded from a comfortable green, humid yellow, tan mugginess, pink oppressive and orange misery (over 75%).

There’s a chart of average wind speed over the year; wind direction, which shows my wrong belief that most of the wind here comes from the west (true in July, December and January only). There’s also (keep scrolling) a chart about the growing season, by which they mean the longest continuous period on non-freezing temperatures, although the chart provides a very visual bigger picture of periods in various temperature bands.

There’s a Growing Degree Days chart! We’re on average at 2000 F GDD at this point in July. Next is a chart of solar energy (average daily incident shortwave solar energy), with kWh peaking in June at 6.9 per day.

There’s more details, but I’m moving on.

Check extreme weather

Lightning Strike map

For when you need to know, check out Real Time Lightning Maps.org. On the map, enlarge the area you are concerned about., and watch for the activity sparking, or click for sound. There’s an explanation of how the data is gathered and what the various color dots mean.

Windy.com has a colored map with streaming arrows, and other settings for rain and thunder, clouds, temperature and more. For those at seas, you can check the waves and swell.

AirNow.gov has a quick-to-read dial of air quality, fire and smoke maps, ozone, fine particulates, lots of information about air quality

Not exactly weather, but if you experience an earthquake, go to Did You Feel It? And register your experience. It helps USGS build a clearer picture of earthquake events in your area. You can see maps of recent earthquakes globally or a world map to give understanding of tectonic plates.

 

Climate Change, or just Weather?

We just had a cold night of 17F, considerably colder than our previous coldest this year (22F). Several people remarked how cold this November has been. Perhaps even colder than any month last winter? I decided to find out.

November 2011 had a low of 22F on 11/12, 11/18 and 11/19. The highest low was  56F on 11/21. The average low was 35.3F. December 2011 had a lowpoint of 18F on 12/12, a warmest night at 60F on 12/7, and the average low was 29.2F. January 2012 had a low point of 9F on 1/25, a “warmest” night of 39F just two days later on 1/27, and an average night low of 22.5F. February 2012 had a coldest night (10F) on 2/13, a warmest night (49F) on 2/2, and an average low of 29.3F.

Young blueberry bush in snow.Photo credit Bridget Aleshire
Young blueberry bush in snow.
Photo credit Bridget Aleshire

So how does this November compare? Our coldest night has been 17F on 11/29, our warmest night 44F on 11/19, with an average of 27.5F. So, November 2012 has had colder nights than Nov 2011 and Dec 2011, but not January 2012.

What about the daytime? Has it been chillier than usual? This November has had a max of  78F on 11/11, a coldest day on 11/27 (46F) and an average of 58.4F, not counting today. November 2011 had a 78F day too (11/14) and much warmer days, the lowest was 50F on 11/17 and 11/18. The average daytime high was 65.9F. Positively balmy! Dec 2011 had a high of 68F on 12/15 and a coldest day at 44F just two days later. The average daytime high was 55.2F. Colder than this November. January 2012 had a high point of 72F on 1/31, a coldest day of 34F on 1/21 and an average daytime temperature of 53F. Also colder than this November.

Overwintered Vates kale.Photo credit Twin Oaks Community
Overwintered Vates kale.
Photo credit Twin Oaks Community

We record our daily max and min temperatures and rainfall, enabling us to compile the weather data from the past several years into some interesting graphs. Each year around this time we write up a report for the community about how our gardening year has gone, which crops were successful, which not. We also include an appendix about the weather that year and previous years. The appendix gets longer with each added year, so we shorten the reports from the oldest years, so as to give prominence to weather most people can remember. Here I’ll include just the past four years.

The Weather Appendix

As always, the weather changes –

  • Our 2012 earthquakes numbers 61-82 were recorded between January and July 31. No more aftershocks of the Aug 23 2011 big quake have been recorded since, although I felt two in August. It’s nice to have that piece of history behind us after a year of nervousness. Our last frost was on 4/24, a very patchy light frost. The previous frosts were 4/11-4/14. This fall we had a patchy frost on 10/13, but no serious one till 11/1. January was cold and dryish with freezing rain on 1/20. February was mild and wet, with one 5″ snowfall. March and April were warm. May was twice as wet as average (7.4″), and warm. We had four days of 90F or more from 5/25. June heated up, with temperatures of 99F on 6/20, and 105F on 6/29. Seven days of 92F or more. July was brutally hot, with 17 or 18 days at 95F or hotter, nine of them 100F or more. The hottest was 107F. Slightly more rain than normal. And of course, the impressive/oppressive humidity. August had “only” six days above 95F, September was milder and rainier, with 5.5″, and no major hurricanes for us. October was warm, with daytime temperatures of 70-86F until the last week (the Hurricane Sandy week). We were extremely lucky with that, only getting about 3″ of rain. In my memory, there were long drought periods when the need to irrigate was relentless, but the data don’t support this memory. Funny, that. We actually had 2-7.4″ every month and the longest dry spell was the first two weeks of April.
  • 2011 was often too rainy. January 1st had a high of 62°F, then the month cooled, with several nights of 10°F, one at 4°F, and two snowfalls. February included 6 days with highs over 68°F, (80°F on 2/18), a dusting of snow, a few nights in the teens and a normal amount of rain (1.9”). March was wet with 6.7” rain (twice normal), 7 days at 70°F or more, 6 nights below 25°F. April had 7 very hot days (90°F or more), average rain, and a patchy last frost on 4/14. May was very wet (6.6”), and warm, ending with a string of days above 90°F. June was also wet (6.2”, including one deluge of 4.1”), hot at each end , two days at 100°F, and milder in the middle. July had a brutal two week drought at the end, and a string of 14 days (including 8/1-8/2) with temperatures above 95°F. The highest was 104°F. August continued with high temperatures, but only 7 days over 95°F. We got too much rain (7.7”), including Hurricane Irene, which gave us 2.8” but could have been so much worse. And there was the 5.8 magnitude earthquake centered a few miles from us on 8/23, and the 59 aftershocks registering 1.8 or higher between then and the last for the year on December 24 (mag 2.4) . November gave us a 17 day gap in aftershocks, up until the 5 in 48 hours 11/19-20. September brought another huge 7.7” rain, including Tropical Storm Lee. Temperatures were nice, although it was often hard to work with the soil getting saturated so often. October was pleasant, if still wet (5.5”), delaying harvest of our potatoes and rotting our winter squash. The first frosts came decisively at 25°F on 10/30 and 10/31. November had 3.9″ of rain, December 5.4″.
  • The winter of 2009-2010 was remarkable for heavy snowfalls. The lowest temperature of the winter was –5°F (1/30). There was a series of 22 Nor’easter storms December to March. The last frost was 5/9, long after the first days above 95°F (4/6 &4/7). 2010 had a brutally hot summer. The days above 95°F were 13 in June, 19 in July, 14 in August, 10 in September. Days above 100°F were 2, 11, 2, 2 for those months. The hottest day was 107°F on 7/24. No major hurricanes affected us, although Nicole gave us 2.5” rain 9/29. Statistically speaking, the rain was a normal amount, but when temperatures are so hot, much more evaporates. On 10/2 there was a magnitude 3.0 earthquake with an epicenter between Mechanicsville and Fredericksburg, and another at Ashland, magnitude 2.4 on 10/30. First frost was 10/23. November was mild, but the cold weather kicked in 12/4/10.
  • 2009 started mild then got extremely cold in mid-January, with temperatures below  –5°F.  We had the first significant snowfall in a few years, and the pond froze over for the first time in at least 3 years. Last frost 4/18. We had average precipitation overall, but it was flood or drought, which isn’t good for the garden. We lost the new Ag Well pump and tank in the Tobacco Barn fire, and had difficulties with irrigation. The hottest day was 98°F.  We had a heat wave in early June, but only eight days of 95°F or higher all year. In early November it rained for about four days straight.  First frost was 10/18.