Victoria Faranca
Student Meteorologist
Pennsylvania State University
Investigative Report – Case Eleven
Introduction:
This is a meteorological analysis to obtain and analyze weather conditions concerning the amount of
snow that fell on October 28, 2008 in Laporte of Sullivan County, PA (Figure 1). This claim concerns the
event that brought an unseasonably early winter storm to Sullivan County. In order to do this, I will
provide meteorological findings to better estimate how much snow fell on this date.
Methodology:
I used several methods to determine the weather conditions in the surrounding area of LaPorte, PA on
October 28, 2008.
Using radar data, observations and modeled data, the amount of snow that fell in LaPorte, PA can be
estimated. Since the NEXRAD RADAR data was unavailable, I used RADAR data from Weather
Underground (Figures 2 - 4). Figure 2 shows that the precipitation associated with the weather system
in question actually began around 7PM the previous day (October 27, 2008). In Figure 3, the RADAR
shows that it was indeed precipitating during the early morning hours on October 28, 2008 in LaPorte,
PA (approximately 2AM). Figure 4 shows the progression of precipitation and its dissipation later in the
day around 4PM. It was during this period (7PM October 27, 2008 to 5PM October 28, 2008) that the
precipitation occurred.
I also used a product from the National Weather Service to then approximate how many inches of liquid
fell on the date in question. Figure 5 shows this precipitation analysis. From this map, it can be
estimated that Sullivan County, PA received between 0.25 and 0.75 inches of liquid precipitation that
day. Using a snow water equivalent ratio of 10:1, (ten inches of snow per one inch of liquid), it could be
assumed that areas within Sullivan County saw a range of snow totals from 2.5 – 7.5 inches. This
meteorological assumption can be verified in Figure 6; a map of observed snow totals showing Sullivan
County with 7.0 inches of observed snow.
The range of snow totals over the county is likely an effect of topographic influences. The elevation of
Sullivan County ranges from 2593 to 779 ft. This implies that the temperature at such elevations will
vary with increasing altitude. The significance here is that higher elevations will see colder temperatures
and thus greater snow amounts. Table 1 shows hourly reports from Williamsport, PA (approximately 30
miles southwest of LaPorte). While these reports are indicative of a rainy day in Williamsport (elevation
528ft), the scenario was quite different in LaPorte (elevation 1972ft). Using the meteorological
approximation of the adiabatic lapse rate to be 6°F per 1000 ft, the approximate temperature in
LaPorte, PA can be estimated (shown in Table 2).
Conclusions:
Based on the evidence provided, the total precipitation through the hours of 7PM October 27, 2008 to
5PM October 28, 2008 was approximately 0.25 to 0.75 inches of liquid. Using the adiabatic lapse rate, it
was indeed cold enough for snow in LaPorte, PA which is at a higher elevation. Using a 10:1 ratio,
LaPorte, PA saw 2.5 – 7.5 inches. These conditions can be hazardous if precautions are not taken.
List of Figures and Tables:
Figure 1(above): Location of Sullivan County, PA indicated in red. LaPorte , PA is located in North
Central Sullivan County.
Figure 2(above): Radar from Weather Underground indicating that precipitation began roughly around
7PM October 27, 2008.
Figure 3(above): Radar from Weather Underground 2AM October 28, 2008.
Figure 4(above): Radar showing precipitation dissipating around 4PM.
Figure 5 (above): National Weather Service precipitation analysis in inches of liquid from October 28,
2008.
Figure 6 (above): 24-hour observed snowfall prior to October 28, 2008.
Table 1 (below): Reported conditions at Williamsport, PA
Time (EDT)
1:54 AM
2:32 AM
2:54 AM
Temp.
42.1 °F
41.0 °F
41.0 °F
Precip
0.02 in
0.02 in
0.04 in
Events
Rain
Rain
Rain
Conditions
Light Rain
Rain
Rain
3:52 AM
3:54 AM
4:54 AM
5:54 AM
6:54 AM
7:54 AM
8:05 AM
8:14 AM
8:45 AM
8:52 AM
8:54 AM
9:01 AM
9:54 AM
10:54 AM
11:54 AM
12:54 PM
1:25 PM
1:54 PM
2:54 PM
3:54 PM
4:54 PM
39.2 °F
39.9 °F
39.9 °F
39.9 °F
41.0 °F
41.0 °F
42.8 °F
42.8 °F
42.8 °F
42.8 °F
42.1 °F
42.8 °F
42.1 °F
42.1 °F
41.0 °F
41.0 °F
42.8 °F
43.0 °F
43.0 °F
43.0 °F
43.0 °F
0.04 in
0.04 in
0.02 in
0.01 in
0.02 in
0.03 in
N/A
N/A
0.01 in
0.01 in
0.01 in
0.00 in
0.04 in
0.02 in
0.01 in
0.01 in
0.00 in
0.00 in
0.00 in
N/A
N/A
Rain
Rain
Rain
Rain
Rain
Rain
Rain
Rain
Rain
Rain
Rain
Rain
Rain
Rain
Light Rain
Light Rain
Light Rain
Light Rain
Light Rain
Overcast
Overcast
Overcast
Light Rain
Light Rain
Light Rain
Light Rain
Overcast
Light Rain
Light Rain
Light Rain
Light Rain
Light Rain
Overcast
Overcast
Scattered
Clouds
Table 2 (below): Estimated temperature at LaPorte, PA based on Williamsport, PA temperature and
elevation.
Time (EDT)
1:54 AM
2:32 AM
2:54 AM
3:52 AM
3:54 AM
4:54 AM
5:54 AM
6:54 AM
7:54 AM
8:05 AM
8:14 AM
8:45 AM
8:52 AM
8:54 AM
9:01 AM
9:54 AM
10:54 AM
11:54 AM
12:54 PM
1:25 PM
Williamsport Temp.
42.1 °F
41.0 °F
41.0 °F
39.2 °F
39.9 °F
39.9 °F
39.9 °F
41.0 °F
41.0 °F
42.8 °F
42.8 °F
42.8 °F
42.8 °F
42.1 °F
42.8 °F
42.1 °F
42.1 °F
41.0 °F
41.0 °F
42.8 °F
LaPorte Temp.
33 °F
32 °F
32 °F
30 °F
31 °F
31 °F
31 °F
32 °F
32 °F
34 °F
34 °F
34 °F
34 °F
33 °F
34 °F
33 °F
33 °F
32 °F
32 °F
34 °F
1:54 PM
2:54 PM
3:54 PM
4:54 PM
43.0 °F
43.0 °F
43.0 °F
43.0 °F
34 °F
34 °F
34 °F
34 °F