Using “wunderground.com”, I recorded seven days of weather in Virginia Beach,
Virginia. Some parts of the weather prediction were very inaccurate, such as the wind speed,
but for most days the temperature was not too wildly off—only by a couple degrees. On
average, the lowest temperature prediction was incorrect by 5.14° Fahrenheit, and the highest
temperature was off by 6° Fahrenheit. The wind speed for the 29th and 30th of December were
closest, even then the forecast was still incorrect by over 5 miles per hour.
Although a majority of the predictions were too different from the actual weather to be
considered very accurate, the first two days were the most reliable. For the 29th, the high/low
temperature and the wind speed only differed by a degree and 5 mph, respectively. The
forecast also predicted a 90% chance of precipitation, which was correct when it rained .45
inches that day. On the 30th, there was only a 20% of precipitation predicted, but it did rain. The
low/high temperature was not as accurate: it was off by 2° and 5°. As the days went on, the
weather forecast became less precise.
Judging from the diverse weather recorded, I believe the beginning of the week was
affected by a low pressure system. The 29th and 30th of December were both cold, cloudy, and
had rained. Low pressure systems typically cause cold, cloudy weather with precipitation
because in areas of low pressure warm air rises, then cools to form clouds. Low pressure
systems also have cold fronts, which have stronger winds. This explains why the wind speed
was so much greater than the rest of the week. In the middle of the week (December 31stJanuary 2nd), the temperature highs increase, there is no precipitation nor clouds, and winds die
down to less than 2 mph. This was a high pressure system affecting Virginia Beach. The last two
days (three if January 2nd is included for overcast clouds) clouds increase, there is a little rain
and winds start to pick up on the 4th. It may possibly be another low pressure system, there
isn’t enough data.
Here in Virginia Beach, predicting the weather is difficult because the ocean affects our
temperatures. Water takes longer to heat up and cool down, so in the daytime cool air from the
ocean moves over land and at night, the coast cools down quickly and the cool air blows over to
the still-warm ocean. These are land and sea breezes. The fact that we are so close to a large
body of water also brings up the fact that any ocean weather has the possibility of drifting over
to land, such as severe thunderstorms or hurricanes.
Wind chill is rate of heat loss (of humans) due the combined effect of temperature and
wind. It makes the temperature feel colder than it actually is. The wind chill temperature is only
found if the temperature is below 50° Fahrenheit and wind speed is over 3 mph.
Meteorologists have two ways of predicting the weather: by persistence forecasting and
climatological forecasting. Persistence forecasting is only accurate enough for the next few
hours because it is predicting the weather will be basically the same as it currently is. It doesn’t
factor in any other weather changes that may occur any more than a few hours later than
current time. Climatological forecasting uses past weather data to predict what will occur in the
future. It’s usually used to predict the probability of one certain element. Keep in mind, this
method is only effective if there aren’t any new factors that are different from past weather
data. As advanced as our technology is today, the weather is ever-changing and unpredictable.
Bibliography
"BOM_Air Pressure." BOM_Air Pressure. N.p., n.d. Web. 05 Jan. 2015.
<http://www.bom.gov.au/lam/Students_Teachers/pressure.shtml#high>.
"National Weather Service Weather Forecast Office." Wind Chill Chart. N.p., n.d. Web. 05 Jan.
2015. <http://www.crh.noaa.gov/ddc/?n=windchill>.
"Weather Wiz Kids Weather Information for Kids." Weather Wiz Kids Weather Information for
Kids. N.p., n.d. Web. 05 Jan. 2015. <http://www.weatherwizkids.com/weather-forecasting.htm>.