Pendleton, Oregon Lightning Densities

1
Pendleton, Oregon Lightning Densities

• Pete Saunders
• Graduate Student
• Florida State University

2
Time Series

• The following graphs depict the total flash
  counts versus the time they occur. The times
  have been converted from UTC to Pacific Standard
  Time (PST). The first graph, entitled Warm
  Season Hourly Counts gives a seasonal
  representation of the time in which most
  lightning flashes occur in Pendleton NWS area of
  interest. The subsequent graphs are a month by
  month illustration.
• The warm season indicates the months of
  April through September over an 11 year period.
  Finally, the area represented in the plots is
  between
• Latitude 42.0 N through 49.0 N
• Longitude -115.0 W through -123.0 W
• Please note The ordinate axes of the following
  graphs are not to scale

3
(No Transcript)
4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
(No Transcript)
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
Remarks

• Examining lightning counts temporally
  illustrates the convective nature of the
  atmosphere climatologically throughout the warm
  season.
• The total flash counts for the months of April
  and September are comparable.
• There is a subtle shift in peak lightning
  counts toward later in the afternoon from April
  through July.
• August has the most lightning flash counts
  with an average of about 35 000, followed by a
  remarkable decrease to only about 800 strikes in
  September.

12
Spatial Density Maps

• The following maps depict the spatial
  densities of CG lightning flashes for the Pueblo,
  Colorado region. The first map, entitled Warm
  Season Flash Density, is a seasonal
  representation for the entire warm season. The
  subsequent maps present a month by month
  comparison of CG flash density.
• Please note
• The coordinates for the density maps are the
  same as previously mentioned for the time series.
  
• The color bar represents different flash
  densities for each month in order to isolate
  features of interest.

13
High relative densities to the east/northeast of
Sacajawea Peak
High ltg. densities in northeastern Klamath
County, Oregon
High relative densities in the Snake River Plain
just to the east of the Owyhee Mountains
14
(No Transcript)
15
Relatively high ltg. density in central Bonner
County, Idaho
16
Sacajawea Peak region
17
Relatively high density here just along the
eastern slope of this part of the Cascade Range
(Border of eastern Douglas County and
northeastern Klamath County)
18
Relatively high densities here in northeastern
Klamath County
19
(No Transcript)
20
Remarks

• There appear to be a few spots in the
  Pendleton NWS area of interest that have
  relatively high CG lightning densities (greater
  than 0.373 flashes per month per km2) throughout
  a given warm season. By examining a topographical
  map of this region, regions of higher CG
  densities are mainly located near areas of abrupt
  elevation change during northerly flow. If this
  is the case, then the high densities in
  northeastern Klamath County seem to be anomalous
  since there is not a clear-cut large elevation
  gradient nearby. Does this overall pattern seem
  reasonable? Do you have an explanation for the
  potentially anomalous area of high densities?
• Any input on the climatological nature of
  the convective season in this region would be
  greatly appreciated. I would love to hear your
  thoughts on why the highest/lowest lightning
  densities occur where they are.
• Also, please share this document with your
  forecasters in order to facilitate feedback and
  understanding.