Martinsville Weather - About / Contact Me / FAQ

Scroll down for the Frequently Asked Questions section.

Personal Biography: My name is Kevin Joyce. I was born in 1985 and have lived here all my life. I graduated 4th in my class from Fieldale-Collinsville High School in 2003, and I graduated from the University of North Carolina at Asheville in 2006 with a degree in Atmospheric Sciences and a minor in Mathematics. I briefly worked at a local TV station before realizing that wasn't exactly what I wanted to do with my life. Currently, I am purusing a teaching career, and assuming things go according to plan, I will begin teaching middle school math in the fall of 2008.
Website History: In the mid to late 1990s, even before I had internet access at my home, I dreamed of someday building a website with my forecast for the Martinsville and Henry County area. That dream gradually came true during the years of 2000 and 2001. Updates were erratic at first, but I have been updating my forecast each day (with a very limited number of missed days) since September 2001. My website is a hobby for me; I have to pay to run it and do not get compensated in any way. I do it because I enjoy it, and because I feel I can provide the people of this area with what is often a more accurate forecast than others provide. More importantly, I believe the honesty and integrity that I try to show in my forecasting (particularly in my discussion), things that are lacking from many other forecasters, are what make my website unique. I intentionally keep my website simple so you can check it quickly, find out what you need to know, and then continue on with your day. However, I also have many other pages that you can check out, such as an extensive weather data archive, and an educational page.
About My Forecast: I update my website each morning, usually around 8 AM unless I have to adjust my schedule for some reason. I also do evening updates (around 7 or 8 PM) sometimes, particularly before and during a winter storm. I use a variety of resources to prepare my forecast each morning, especially computer model data and the National Weather Service forecast, but everything you see on this website is by me personally. I believe that the fact that I focus on this small area, combined with my years of experience forecasting for Martinsville, are the two main factors that contibute to my generally high forecast accuracy. My average forecast accuracy has steadily risen over the years from about 83% in 2003 to just over 90% in 2007. (See the FAQ below for an explanation of how my forecast accuracy is calculated.) Thank you for taking the time to read this, and I hope you enjoy my website!

Why are your low temperatures offset from everything else in your 10 Day Planner?
Since low temperatures occur in the overnight/early morning hours, sometimes it can be confusing as to which day a low temperature forecast is for. For example, if you see a forecast low of 30° on Sunday, is that for Sunday morning or Sunday night? By offsetting the low temperature column, this is supposed to eliminate that confusion. The low temperature forecast that is located between Sunday and Monday's forecasts is the forecast low for Sunday night/Monday morning. (Please note that low temperatures usually occur each morning around sunrise, and not actually in the middle of the night.)
What does your Forecast Confidence Level indicate?
This indicates how confident I am in my forecast. My confidence is indicated by one of the following: Very High, High, Moderate, Low, and Very Low. A very high confidence level indicates that I am nearly 100% certain that my forecast weather for that particular day will be correct, and I feel like my forecast high and low will be correct or at least very close to the actual values. On the other hand, a very low confidence level indicates that there is a lot of uncertainty for that day, usually regarding the timing of an expected precipitation event.
What is the Regional School Forecast?
This section shows my forecast for the chance that schools will be open each day for the next 10 days. The highest I will go is 99%, because anything can happen (even non-weather related events such as a fire or bomb threat). If I have a 0% chance, that school or school system has announced that it is closed for that day or it is a scheduled holiday. (Please note that although I use the calendars from each school system, I sometimes make mistakes with regard to scheduled holidays. Also, I often have a difficult time finding out when school systems make up days that they have missed. If I have 0% for you and it is not a snow day, be sure to check your school schedule to make sure that you have the day off. If you notice a mistake in my school forecast with regard to a holiday or make-up day, please let me know immediately!) Even if there is a lot of snow on the ground and schools will obviously be closed the next day, I won't go below 10% until an official announcement has been made. This section is different from my 10 day forecast because I also have to take into account how long it will take the snow to melt as well as how quickly the roads get plowed. Obviously this section is most often used for snow, but the possibility of school closings due to other weather events (flooding, hurricanes, etc.) is also taken into account.
What is the Forecast Discussion?
This is where I express my thoughts and opinions on my forecast and how confident I am in it. This is one thing that I think sets me apart from other forecasts because I don't just make a forecast but I also explain my reasoning behind it; I also give other possible scenarios if I have lower confidence in my forecast. I talk about computer models quite frequently in my discussions, and a brief explanation of those can be found below the discussion.
Where does your Local Climatology data come from?
The high and low temperatures come from the Blue Ridge Regional Airport in Spencer. As of November 1, 2007, precipitation data also comes from the airport. Prior to that date, it came from my rain gauge.
What is the difference between 24 hour high/low temperatures and afternoon highs/morning lows?
You may be wondering why the 24 hour high and low temperatures and the afternoon high/morning low temperatures are occasionally different. The 24 hour high and low reflect the highest and lowest temperatures for the entire day, from 12:00 AM until 11:59 PM. Most of the time, the low occurs in the morning and the high occurs in the afternoon. However, this is not always the case. For example, on a day when a strong cold front moves through in the morning, the highest temperature for the day may occur early in the day as the colder air moves in, causing the temperature to fall during the afternoon. The afternoon high and morning low are necessary for me to be able to calculate my forecast accuracy on days such as the one in that example.
What are Heating Degree Days and Cooling Degree Days?
Heating Degree Days and Cooling Degree Days are used for agricultural purposes, as well as other things. The formula to calculate these is simple; it is just the number of degrees the mean (average) temperature for the day departs from 65°F. For example, if the high is 50°F and the low is 30°F, the mean would be 40°F, and there would be 25 heating degree days (65-40). If the high is 90°F and the low is 70°F, the mean would be 80°F, and there would be 15 cooling degree days (80-65).
How do you calculate your Forecast Accuracy?
I calculate my forecast accuracy using several formulas within a spreadsheet. First, I put in how far off each part of my forecast was (weather, high, low) from the actual weather. The numbers for high and low temperatures are how many degrees I was away from the actual. The weather is a bit more complicated, and is more my opinion. For example, if the weather was Sunny and I had forecasted Cloudy, it wouldn't be as many points against me as if it was Sunny and I had forecasted Heavy Rain. I also factor my forecast confidence into the calculation. If I have low confidence in a forecast, I don't count off quite as much as when I have high confidence. After coming up with the 10 daily figures, a separate formula combines them into one final number, my 10 Day Weighted Accuracy. This figure puts more weight on Day 1 than Day 10 to account for more error with longer range forecasts. (If the date the forecast is valid is February 5, Day 1 would be February 5 and Day 10 would be my forecast for February 5 from 10 days earlier, January 27.) The 2 Week Graph is a graph of my 10 Day Weighted Accuracy from the past two weeks.