Kevin Hansen
Weather Forecast
Meteorology 1010-003
Weather Forecast
Contents
NATIONAL CONDITIONS PRIOR TO FORECAST (12/5/2011):
4
National Temperatures
4
National Wind Speed and Direction
5
Observation of Current Weather Status:
5
TEMPERATURE
6
Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
6
Conditions for Denver, Colorado End of Day – 12/06/2011:
8
Conditions for Denver, Colorado End of Day – 12/07/2011:
10
APPARENT TEMPERATURE
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Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
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Conditions for Denver, Colorado End of Day – 12/06/2011:
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Conditions for Denver, Colorado End of Day – 12/07/2011:
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RELATIVE HUMIDITY
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Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
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Conditions for Denver, Colorado End of Day – 12/06/2011:
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DEWPOINT
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Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
11
Conditions for Denver, Colorado End of Day – 12/06/2011:
12
SKYCOVER
Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
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Kevin Hansen
Weather Forecast
Conditions for Denver, Colorado End of Day – 12/06/2011:
WIND GUST
Meteorology 1010-003
14
15
Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
15
Conditions for Denver, Colorado End of Day – 12/06/2011:
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WIND SPEED AND DIRECTION
17
Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
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Conditions for Denver, Colorado End of Day – 12/06/2011:
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REFLECTIONS
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Introduction – Scope of Assignment
The following details breakdown the specifics of the forecasting assignment:
1) Using the Newspaper, TV, Internet, etc., for data and guidance – make a forecast for Denver,
Colorado for Wednesday, December 6, 2011 and Thursday, December 7, 2011. Include the same
elements in the forecast as you have with the other forecast in this assignment. Include in the
forecast:
A. Trends in the Temperature
B. Trends in the Wind Speed and Direction
C. Trends in the Sky Cover
D. Trends in Precipitation and the Types of Precipitation
E. A High Temperature for the 24 hour period
F. A Low Temperature for the 24 hour period
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
National Conditions Prior to Forecast (12/5/2011):
National Temperatures
4
Kevin Hansen
Weather Forecast
Meteorology 1010-003
National Wind Speed and Direction
Observation of Current Weather Status:
5
Kevin Hansen
Weather Forecast
Meteorology 1010-003
Temperature
Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
Prediction for 12/6/2011
General Comments: The front appears to be moving in a South-Easterly direction (NW wind) at a rate
of about 10kts. I therefore used temperatures from the western border area between Utah and
Colorado as a basis for the projection. I also considered cloud cover for high and low temps. Dew point
was also considered to determine if there would be precipitation and its ensuing effect on
temperatures. Furthermore, I considered wind speed and direction to determine if advection would
impact the temperature. This was done by looking at the temperatures upstream of Denver. Also,
Sloped terrain produces downsloping and upsloping wind especially when the wind direction is
perpendicular to the slope of the terrain. Denver is located on the eastern side of the Rockies, so this
must be considered. A wind direction forecast is critical in determining how much adiabatic warming or
cooling will occur along the slope. Upslope cooling in the cool season can produce adiabatic cooling and
snow while downslope flow produces adiabatic warming and a chinook wind. Ultimately, this effect was
not a huge factor since most of the data I forecasted off came from a similar close mountainous region.
High: 38F
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Comments: During the day, the earth is heated by the sun. If skies are clear, more heat reaches the
earth's surface. This leads to warmer temperatures. However, if skies are cloudy, some of the sun's rays
are reflected off the cloud droplets back into space. Therefore, less of the sun's energy is able to reach
the earth's surface, which causes the earth to heat up more slowly. This leads to cooler temperatures.
When forecasting daytime temperatures, if cloudy skies are expected, forecast lower temperatures than
you would predict if clear skies were expected
Low:
15F
Comments: At night cloud cover has the opposite effect. If skies are clear, heat emitted from the
earth's surface freely escapes into space, resulting in colder temperatures. However, if clouds are
present, some of the heat emitted from the earth's surface is trapped by the clouds and reemitted back
towards the earth. As a result, temperatures decrease more slowly than if the skies were clear. When
forecasting nighttime temperatures, if cloudy skies are expected, forecast warmer temperatures than
you would predict if clear skies were expected.
Actual for 12/6/2011
High: 40F
Low:
21F
Conclusion: The predicted temperatures were close. I feel this isn’t so much because of my accuracy,
but rather because of lack of a developing low pressure area. The weather in Denver, Colorado is
stagnant and at the time of forecast there were not many changes to the sources which impact
temperature.
7
Kevin Hansen
Weather Forecast
Meteorology 1010-003
Conditions for Denver, Colorado End of Day – 12/06/2011:
Prediction for 12/7/2011
General Comments: The front appears to be moving in a South-Easterly direction (NW wind) at a rate
of about 10kts. I therefore used temperatures from the western border area between Utah and
Colorado as a basis for the projection. I also considered cloud cover for high and low temps. Dew point
was also considered to determine if there would be precipitation and its ensuing effect on
temperatures. Furthermore, I considered wind speed and direction to determine if advection would
impact the temperature. This was done by looking at the temperatures upstream of Denver. Also,
Sloped terrain produces downsloping and upsloping wind especially when the wind direction is
perpendicular to the slope of the terrain. Denver is located on the eastern side of the Rockies, so this
must be considered. A wind direction forecast is critical in determining how much adiabatic warming or
cooling will occur along the slope. Upslope cooling in the cool season can produce adiabatic cooling and
snow while downslope flow produces adiabatic warming and a chinook wind. Ultimately, this effect was
not a huge factor since most of the data I forecasted off came from a similar close mountainous region.
High: 33F
Comments: During the day, the earth is heated by the sun. If skies are clear, more heat reaches the
earth's surface. This leads to warmer temperatures. However, if skies are cloudy, some of the sun's rays
are reflected off the cloud droplets back into space. Therefore, less of the sun's energy is able to reach
8
Kevin Hansen
Weather Forecast
Meteorology 1010-003
the earth's surface, which causes the earth to heat up more slowly. This leads to cooler temperatures.
When forecasting daytime temperatures, if cloudy skies are expected, forecast lower temperatures than
you would predict if clear skies were expected
Low:
18F
Comments: At night cloud cover has the opposite effect. If skies are clear, heat emitted from the
earth's surface freely escapes into space, resulting in colder temperatures. However, if clouds are
present, some of the heat emitted from the earth's surface is trapped by the clouds and reemitted back
towards the earth. As a result, temperatures decrease more slowly than if the skies were clear. When
forecasting nighttime temperatures, if cloudy skies are expected, forecast warmer temperatures than
you would predict if clear skies were expected.
Comments: The front appears to be moving in a South-Easterly direction at a rate of about 10mph. I
therefore used temperatures from the general Salt Lake City area as a basis for the projection.
Actual for 12/7/2011
High: 36F
Low:
21F
Conclusion: The predicted temperatures were close. I feel this isn’t so much because of my accuracy,
but rather because of lack of a developing low pressure area. The weather in Denver, Colorado is
stagnant and at the time of forecast there were not many changes to the sources which impact
temperature.
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Conditions for Denver, Colorado End of Day – 12/07/2011:
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Dewpoint
Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
Prediction for 12/6/2011: 1F
Comments: The dew point is a measure of moisture; it shows how much you'd have to cool the air to
get a relative humidity of 100 percent. The higher the dew point, the more water vapor there is for
producing rain or snow. The dew point appears to be low, so I would not anticipate a great chance of
precipitation. It is important to maintain an awareness of dew point temperatures as it affects primarily
fire weather planning, fog, aviation, and convective weather forecasting.
Actual for 12/6/2011: 12F
Conclusion: I was way off on the dew point prediction. I thought because of the lack of precipitation,
the dew point would be close to zero. I was wrong.
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Conditions for Denver, Colorado End of Day – 12/06/2011:
Prediction for 12/7/2011:
5F
Comments: The dew point is a measure of moisture; it shows how much you'd have to cool the air to
get a relative humidity of 100 percent. The higher the dew point, the more water vapor there is for
producing rain or snow. The dew point appears to be low, so I would not anticipate a great chance of
precipitation. It is important to maintain an awareness of dew point temperatures as it affects primarily
fire weather planning, fog, aviation, and convective weather forecasting.
Actual for 12/7/2011:
7F
Conclusion: After learning of my mistake the prior day, I was more conservative in my approach and
the end result was closer to the actual number. That being said, I still don’t have a lot of confidence in
forecasting the dew point.
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Skycover
Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
Prediction for 12/6/2011:
5%
Comments: The front appears to be moving in a South-Easterly direction (NW wind) at a rate of about
10kts. I therefore estimated sky cover based on the sky cover from the western border area between
Utah and Colorado as a basis for the projection.
Actual for 12/6/2011:
28%
Conclusion: I thought sky cover would be minimal, based off of the sky cover at the time of prediction
for the Utah/Colorado border. I was wrong and somewhat confused by this. I believe the main
determinant is the lack of low pressure.
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Conditions for Denver, Colorado End of Day – 12/06/2011:
Prediction for 12/7/2011:
25%
Comments: The front appears to be moving in a South-Easterly direction (NW wind) at a rate of about
10kts. I therefore estimated sky cover based on the sky cover from the western border area between
Utah and Colorado as a basis for the projection.
Actual for 12/7/2011:
38%
Conclusion: This time I was more conservative in my approach to sky cover. Unfortunately, I was still
far from the correct percentage. I underestimated the effect of drainage winds causing cloud cover.
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Wind Gust
Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
Prediction for 12/6/2011:
8kts
Comments: The front appears to be moving in a South-Easterly direction (NW wind) at a rate of about
10kts. I therefore estimated sky cover based on the sky cover from the western border area between
Utah and Colorado as a basis for the projection.
Actual for 12/6/2011:
1kts
Conclusion: Difficult to forecast. I chose a number which was a median for the prior day’s wind gusts.
There is not much various due to the high pressure.
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Conditions for Denver, Colorado End of Day – 12/06/2011:
Prediction for 12/7/2011:
10kts
Comments: The front appears to be moving in a South-Easterly direction (NW wind) at a rate of about
10kts. I therefore estimated sky cover based on the sky cover from the western border area between
Utah and Colorado as a basis for the projection.
Actual for 12/7/2011:
4kts
Conclusion: Winds were higher than the day before, yet my projection was still off. Indications are a
low pressure area is slowing moving in.
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Wind Speed and Direction
Conditions for Denver, Colorado Prior to Forecast (12/5/2011):
Prediction for 12/6/2011:
7kts NW
Comments: The front appears to be moving in a South-Easterly direction (NW wind) at a rate of about
10kts. I therefore estimated sky cover based on the sky cover from the western border area between
Utah and Colorado as a basis for the projection.
Actual for 12/6/2011:
1kts NE
Conclusion: Same result as prediction for wind gusts. I chose a number which was a median for the
prior day’s wind gusts. The wind direction was completely different from what I thought it would be.
There is not much various due to the high pressure.
17
Kevin Hansen
Weather Forecast
Meteorology 1010-003
Conditions for Denver, Colorado End of Day – 12/06/2011:
Prediction for 12/7/2011:
10kts W
Comments: The front appears to be moving in a South-Easterly direction (NW wind) at a rate of about
10kts. I therefore estimated sky cover based on the sky cover from the western border area between
Utah and Colorado as a basis for the projection.
Actual for 12/7/2011:
4kts NW
Conclusion: Winds have increased and cyclogenesis is starting to occur. I was closer in my prediction
this time.
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Kevin Hansen
Weather Forecast
Meteorology 1010-003
Reflections
I'm sure we've all had experiences when we were counting on a weather forecast to be accurate.
Outdoor weddings, vacations, and outdoor parties are events that come to my mind when I think of plans
I've made that have depended on the weather forecast. However, I’ve learned from this assignment that
weather forecasting is no simple or easy task! In fact, Arduous is a word that comes to mind after going
through the process of forecasting the weather.
Because of innovation, the general public leans on technology for answers. I’ve learned that while
computer models are very reliable tools, we must still take the information these tools give us and put
them into context with what we know about the structure of weather systems.
This assignment taught me the importance of consistency and coordination in forecasting the weather. I
had to take several different concepts I learned from the semester and apply them in the correct order to
be successful in finding the end result.
In summary, taking this course has given me a greater appreciation for Meteorology and its associated
concepts. Because of taking Meteorology my thoughts now give prose to that of a question asked at the
139th Annual Meeting of The American Association for the Advancement of Science - Predictability: Does
the flap of a butterfly's wings in Brazil set off a tornado in Texas?
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