assessment of thirty year fog climatology in wichita forecast area by: matthew harding, butler...
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Assessment of Thirty Year Fog Climatology in Wichita Forecast Area
By: Matthew Harding, Butler Community College, El Dorado, Kansas
Kenneth Cook, Science Operations Officer, National Weather Service, Wichita, Kansas
Basis for Assessment
• Data was collected over a thirty year period beginning in 1976 and ending in 2006.
• Data was collected from all five of the Terminal Aerodrome Forecast (TAF) sites that are serviced by the Wichita Forecast Office.
• Data sampling was oriented in northwest-to-southeast fashion across the County Warning Area (CWA) to include Russell, Wichita, and Chanute.
Goals of Assessment
1. To give the forecaster knowledge about climatological peaks in the number of hours where fog is reported.
2. Enhance the forecaster’s ability to issue dense fog/freezing fog advisories.
3. Give forecasters a better understanding of ceiling/visibility relationships in fog scenarios.
4. Better explain why certain times of the year produce more fog than others.
Methodology
• Data was compiled using the following criteria:
1. Compiling the total number of hours over the 30-year period that fog was reported at the observation site.
2. Taking the number of total fog hours over the 30-year period and break it down into an hourly distribution.
Methodology (Cont.)
3. Take only the hours that reported visibility of less than 5 statute miles and break it down into an hourly distribution by mileage category. I. 3 to 5 mi.II. 2 to less than 3 mi.III. 1 to less than 2 mi.IV. .5 to less than 1 mi. V. Less than .5 mi.
4. Take the number in each of the categories above and divide that into the total number of fog hours for the month for each station and come up with a distribution percentage.
Methodology (Cont.)
5. Determine the percentage of fog observations that have a ceiling below 3000 feet by month.
6. Of these, determine the average ceiling for the given visibility category by month.
7. With the given data, find the .75 and .25 percentile to come up with the degree of variability.
Results and Discussion Russell, Kansas
Russell Municipal Airport
January
Febru
ary
Marc
hApril
May
June
July
August
September
October
November
December
0
500
1000
1500
2000
2500
3000
3500
4000
Total Fog Hours
Months of Year
Num
ber o
f Fog
Hou
rs
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour
JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
Hour of Day (Time in UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Winter
DecemberJanuaryFebruary
Hour of Day (Time in UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Spring
MarchAprilMay
Hour of Day (Time in UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Summer
JuneJulyAugust
Time of Day (Time in UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Fall
SeptemberOctoberNovember
Time of Day (Time in UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
January
Febru
ary
Marc
hApril
May
June
July
August
September
October
November
December
0
10
20
30
40
50
60
70
80
90
100
Percentage of Less Than 3,000 ft Ceilings Heights in Fog Observations
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
RSL December Cig/Vis
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
RSL April Cig/Vis
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
RSL July Cig/Vis
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
RSL October Cig/Vis
Wichita, Kansas Wichita Mid-Continent Airport
January
Febru
ary
Marc
hApril
May
June
July
August
September
October
November
December
0
500
1000
1500
2000
2500
3000
3500
4000
Total Fog Hours
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour
JanuaryFebruaryMarchAprilMayJuneJuly AugustSeptemberOctoberNovemberDecember
Hour of Day (Time in UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Winter
DecemberJanuaryFebruary
Time of Day (in UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Spring
MarchAprilMay
Time of Day (In UTC)
Num
ber o
f Fog
Hou
rs R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Summer
JuneJuly August
Time of Day (In UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Fall
SeptemberOctoberNovember
Time of Day (In UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
January
Febru
ary
Marc
hApril
May
June
July
August
September
October
November
December
0
10
20
30
40
50
60
70
80
90
100
Percentage of Less than 3,000 ft Ceiling Heights in Fog Ob-servations
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
ICT December Cig/Vis
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
ICT April Cig/Vis
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
ICT July Cig/Vis
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
ICT October Cig/Vis
Chanute, Kansas Chanute Martin Johnson Airport
January
Febru
ary
Marc
hApril
May
Ju
neJu
ly
August
September
October
November
December
0
500
1000
1500
2000
2500
3000
3500
4000
Total Fog Hours
Month of Year
Num
ber o
f Fog
Hou
rs
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour
JanuaryFebruaryMarchApril May June JulyAugustSeptemberOctoberNovemberDecember
Hour of Day (In UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Winter
DecemberJanuaryFebruary
TIme of Day (In UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Spring
MarchApril May
Time of Day (In UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Summer
June JulyAugust
Time of Day (In UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
0 UTC2 UTC
4 UTC6 UTC
8 UTC
10 UTC
12 UTC
14 UTC
16 UTC
18 UTC
20 UTC
22 UTC0
50
100
150
200
250
Fog Occurrences by Hour--Fall
SeptemberOctoberNovember
Time of Day (In UTC)
Num
ber o
f Hou
rs F
og R
epor
ted
January
Febru
ary
Marc
hApril
May
June
July
August
September
October
November
December
0
10
20
30
40
50
60
70
80
90
100
Percentage of Less Than 3,000 ft Ceiling Heights in Fog Ob-servations
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
CNU December Cig/Vis
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
CNU April Cig/Vis
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
CNU July Cig/Vis
3 to 5 2 to < 3 1 to < 2 .5 to < 1 < .5
25% 1 2 3 4 5
250
750
1250
1750
2250
2750
CNU October Cig/Vis
Summation
• In a study conducted by the National Transportation Safety Board from 1995-2000, weather was cited as being a factor in 3 out of every 10 fatal aircraft accidents (Pearson 2002).
• Data from the same study also indicated that 63% of all weather-related aircraft disasters happened in low ceilings and fog (Pearson 2002; Cox, 2007).
Summation (Cont.)
• While strides are being made in TAF forecasting, fog development and subsequent cloud heights remain one of the greatest forecast challenges.
• We hope that with the data shown in previous slides, that you recognize the tendencies in climatology and are now better equipped to serve your aviation clientele.