Field Journal and Final Report of Weather Observations:
MARCH 28 – MAY 26 2011 for BREMERTON, WASHINGTON
A term project for Meteorology 101 Spring 2011. The material was compiled by interpreting daily written and illustrated field journal observations of local weather phenomenon.
A few samples of the daily weather field journal (above):
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FINAL REPORT:
Abstract:
This paper documents and interprets a study of weather events in Bremerton, Washington for the period including March 28 through May 26, 2011.
A history of temperature, precipitation, wind, barometric pressure, daylight hours and relative humidity were compiled through personal observation and recorded readings from established weather reporting sources. Graphic illustrations of data are included with interpretations.
FINAL REPORT SUMMARY
LIMITATIONS of the STUDY
OVERALL TRENDS
INTERPRETATIONS:
DAILY TEMPERATURES and CLOUDCOVER
RELATIVE HUMIDITY and WINDSPEED
HUMIDITY and BAROMETRIC PRESSURE
RELATIVE HUMIDITY and PRECIPITATION
BAROMETRIC PRESSURE and PRECIPITATION
WIND-SPEED and ACCUMULATED DAILY RAINFALL
WIND DIRECTION
CONCLUSION
DATA TABLE INDEX
SOURCES
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FINAL REPORT SUMMARY:
During the term I recorded daily of weather observations, detailing high and low temperatures, barometric pressure, relative humidity, total daylight hours, daily precipitation, wind speeds and future predictions, using eyewitness reports and published information from an established weather reporting service. These were compiled in a journal, and accompanied by illustrations, detailed written observations and photographs taken at the time the observations were made (Fern: 2011). I used the Weather Underground reporting service for my information, excluding 3 days when the service had incomplete readings; for these days I used the
Bremerton Kitsap Sun newspaper’s published weather reports and predictions. After completing nine weeks of observations, I compiled the figures into pertinent graphs and tables. In some cases I saw patterns of relation between separate charts; I combined these into comparative graphs to help determine if relationships exist.
LIMITATIONS:
The values for humidity, wind speed and barometric pressure are from single readings only, while the precipitation, temperature and daylight hour values are calculated over a 24 hour period. Because of this, drawing definite conclusions when compiling and comparing these values will likely give an inaccurate view. Variables such as taking readings at varying times of day, or taking readings after sunset most likely influenced my results in a different direction from someone who took their readings every day at 12:30 pm, especially the wind and humidity readings. This makes the conclusions I draw regarding rainfall and humidity or rainfall and barometric pressure less conclusive than I would prefer.
There is also one day of extraordinarily high rainfall, March 30, which makes the other events in that graph seem disproportionally small. I have not made a series of graphs that exclude that day to see if other patterns emerge. The highest wind reading is also from that day, but is in better proportion with its graph.
Finally, the arbitrary system I devised for rating cloud-cover may be constructed in a way that someone else would not choose to do.
During the term I recorded daily of weather observations, detailing high and low temperatures, barometric pressure, relative humidity, total daylight hours, daily precipitation, wind speeds and future predictions, using eyewitness reports and published information from an established weather reporting service. These were compiled in a journal, and accompanied by illustrations, detailed written observations and photographs taken at the time the observations were made (Fern: 2011). I used the Weather Underground reporting service for my information, excluding 3 days when the service had incomplete readings; for these days I used the
Bremerton Kitsap Sun newspaper’s published weather reports and predictions. After completing nine weeks of observations, I compiled the figures into pertinent graphs and tables. In some cases I saw patterns of relation between separate charts; I combined these into comparative graphs to help determine if relationships exist.
LIMITATIONS:
The values for humidity, wind speed and barometric pressure are from single readings only, while the precipitation, temperature and daylight hour values are calculated over a 24 hour period. Because of this, drawing definite conclusions when compiling and comparing these values will likely give an inaccurate view. Variables such as taking readings at varying times of day, or taking readings after sunset most likely influenced my results in a different direction from someone who took their readings every day at 12:30 pm, especially the wind and humidity readings. This makes the conclusions I draw regarding rainfall and humidity or rainfall and barometric pressure less conclusive than I would prefer.
There is also one day of extraordinarily high rainfall, March 30, which makes the other events in that graph seem disproportionally small. I have not made a series of graphs that exclude that day to see if other patterns emerge. The highest wind reading is also from that day, but is in better proportion with its graph.
Finally, the arbitrary system I devised for rating cloud-cover may be constructed in a way that someone else would not choose to do.
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| fig 1 |
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| fig 2 |
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| fig 3 |
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| fig 4 |
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| fig 5 |
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| fig 6 |
OVERALL TRENDS:
Barometric pressure (figure 1) and relative humidity (figure 2) both showed an overall decreasing trend for the period of the study, as did daily precipitation amounts (figure 3) and wind speeds (figure 4), while the total daylight hours (figure 5) showed a steady increase of approximately 3 ½ minutes a day. The daily low and high temperatures (figure 6) showed an overall increasing temperature trend for both daily measurements, as well as an increasing difference between the daily lows and highs.
INTERPRETATIONS:
DAILY TEMPERATURE FLUCTUATIONS and CLOUD-COVER:
I wondered if the increasing difference between daily low and high temperatures was related to something more than increasing daylight hours. By combining information from my drawings, descriptions, and the predicted chance of precipitation for that day’s weather forecast, I devised a rating system for the degree of overcast skies, and graphed this data.
The method I used to rate the amount of overcast skies was such that if my drawings and daily observations indicated cirrus or no clouds and the prediction for rain was 0-30%, I rated this day as a zero. If cirrus, altostratus and cumulus combinations were indicated with a rating up to 60% chance of rain, I rated this day as a one. If cumulus congestus, cumulonimbus or nimbostratus were described along with rain or low visibility, and a 60% chance of rain or greater, I rated this day as a two.
In most points on the graph, a low cloud-cover rating of zero coincides with a higher daily temperature difference. This shows that radiant heat from the earth was dissipating at night more quickly when no cloud cover existed, and is also a demonstration of the insulating properties of the clouds, when they are present in days with a one or two rating. Because this system is somewhat anecdotal I would like to establish a better way of defining its grading system for future record keeping.
RELATIVE HUMIDITY and WINDSPEED:
This graph shows a fairly random pattern. Although several spikes coincide, there are just as many instances where they do not. In some cases, a high humidity coincides with a zero wind-speed, or a low humidity with a high wind-speed; in others, a spike in humidity occurs after several days of still air; in still others, a coinciding rise of both is followed by a plunging wind-speed, and then a dropping humidity. These all seem to explain valid reasons for the data, but still do not show a discernable pattern; in the future, I would like to take at least one day and one night reading each 24 hour period, in hopes to correct for not taking my readings at the same time every day.
HUMIDITY and BAROMETRIC PRESSURE:
This graph appears to have the most pronounced reflexive readings of all the combined graphs. Almost without exception, a rise in pressure occurs with a drop in humidity throughout the study period; in the cases where this is not apparent, the relative rise and fall in preceding and following points establish the relative pattern.
RELATIVE HUMIDITY and PRECIPITATION:
This graph shows a direct relationship between the two. On March 30 the highest daily rainfall of the study is preceded by an increase in humidity although the recorded rain fall for that day is less than the preceding day; March 31 has very little rain by comparison, but the humidity continues to rise because of the saturated ground, as well as the increase in temperature, which raises the dew-point. April 1 brings more rain than the day before, and the humidity rises again, only dropping a day after the rain has subsided. This is an established pattern throughout the study. The humidity rises in advance of rain and drops at a lag rate after the rain has stopped. In periods of little rain, like April15th through April 23rd, or April 29th through May 10th, I was surprised to see the fluctuations in humidity. After comparing with the cloud-cover graph, I can see a reflexive pattern between the two. This helps make sense of the humidity variances during times of little rain, and also explains the presence of cumulus build-up.
Another comparison between the Relative Humidity & Precipitation (table IX), and Daily Temperature Fluctuations & Cloudcover graphs show an interesting series from April 23rd -25th. On the 23rd there is no precipitation, the humidity is 28%, and the change in temperature is 36 degrees, from a low of 32o to a high of 68o. The 24th, the humidity spikes to 94% after the day’s high temperature drops to 50o, the difference between temperatures shrinks, and it rains about a fifth of an inch.
BAROMETRIC PRESSURE and PRECIPITATION:
In almost every point on this graph, the pressure and precipitation are reflexive, much like the combination graph of humidity and barometric pressure. In some cases the pressure and precipitation appear to deviate from the reflexive pattern, but if the two lines are interpreted independently and in context of their medians, the two graphs still react in opposite directions. This graph shows that when the barometric pressure rises, the amount of precipitation drops. When the barometric pressure is in a high trend, there is little or no rain. In the period from April 13th through April 23rd there is relatively little rainfall, but several spikes in barometric pressure. Upon closer examination, the spikes in pressure are in sync with variances in rainfall; this pattern is not apparent at first because of the high volume of precipitation on March 30th minimizes the chart’s pattern for the rest of the study.
There is a definite trend throughout the study period between wind and rainfall. In many examples, the events are concurrent, showing a storm event; in the remainder, a rise in wind-speed precedes a spike in rainfall, indicating an advancing front.
WIND DIRECTION:
The winds overwhelmingly occurred from a southerly direction during the study.
The dates where the winds were not from the south were:
April 6-7th had north winds, a drop in pressure and measurable rain;
April 11th had easterly winds, zero rainfall and a spike in barometric pressure;
April 20-22nd showed winds from west to east and to north, with a low-high-sinking pressure pattern, and trace amounts of rain;
May 3-4th had north winds, strongly rising barometric pressure, and trace rains;
May 14th had westerly winds, dramatically dropping pressure and a spike in rainfall;
May 17th had north winds, a temporary drop in barometric pressure, and zero rainfall (Fern 2011).
From this information I can only conclude that a variation from the normal wind direction indicates change is
coming, but a definite pattern of associated weather phenomena and wind direction is not conclusive. This is an area that needs a longer study period to establish if a pattern exists.
CONCLUSION: I learned several unexpected things in the course of this project. I was surprised to find that, although this has been an especially cool and seemingly wet spring, the amount of accumulated rainfall each day was much less than I expected it to be. In the midst of the daily grind of keeping the weather journal I was unaware of the connections that I had documented; I can now see these after compiling and writing this report. In looking back through the nine weeks of observations I can also see an increasing understanding of the causes and effects of what I was documenting; this was surprising to me because at times I felt as though I wasn’t making progress in learning the concepts and terms taught in this class, because I hadn’t stepped back and regarded the journal as a whole until this time. Finally, in undertaking this project, I was reminded how challenging, habit-forming and rewarding an experience record keeping can be. After completing this course, I will pay closer attention to what is happening in this region’s weather, now that I have a better understanding of what I see.
SOURCES:
Fern, Anna K. (2011) Daily weather observations
journalKitsap Sun (2011) Bremerton newspaper, May 12 and 13, 2011
Weather Underground, The (2011) online weather reporting from APRS weathernet , east of Pendergast Park, Bremerton Washington. http://wunderground.com
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