Snowfall
Outlook for the 2004-2005 Winter Season
Residents of Pennsylvania experienced treacherous conditions
for the past two winter seasons, 2002-2003 and 2003-2004. So, now that summer
is swiftly coming to a close, the question buzzing in everyone’s mind is “What
can we expect for the winter of 2004-2005?” (Or, perhaps everyone would prefer
to bask in summer’s glory without even sparing a moment to consider what Mother
Nature has in store for us this winter.) In order to satiate our need to know,
this investigation employs the analog method, which is used in our monthly experimental
forecasts, to obtain a first glance at the expected snowfall for the 2004-2005
winter season.
Based upon the analog method described below, 1977-1978
and 1978-1979 represent the two consecutive winters most closely related to
consecutive winters 2002-2003 and 2003-2004. Therefore, the 2004-2005 winter
season could be expected to most closely resemble the winter of 1979-1980, which
resulted in below normal snowfall amounts throughout Pennsylvania (see
Table 1). Pictorial representations of the expected snowcover patterns for
December 2004, January 2005 and February 2005 are provided below in Figures
1, 2 and 3.
|
Climate Division
|
December 1979
|
January 1980
|
February 1980
|
|
1
|
-3.0
|
-12.8
|
.3
|
|
2
|
.9
|
-9.2
|
-2.7
|
|
3
|
.2
|
-5.3
|
-6.5
|
|
4
|
-3.3
|
-5.5
|
-6.9
|
|
5
|
-2.3
|
-9.4
|
-4.8
|
|
6
|
-4.7
|
-12.6
|
-3.2
|
|
7
|
-5.7
|
-9.2
|
-3.6
|
|
8
|
-7.1
|
-6.2
|
-4.4
|
|
9
|
-5.7
|
-3.8
|
.4
|
|
10
|
-10.1
|
-10.5
|
1.7
|
Table 1: Departure
from normal snowfall for winter 1979-1980 by PA climate division.
The following procedures were employed to predict expected
snowfall for the 2004-05 winter season:
1) Compared snow cover anomalies of the 2002-2003 and
2003-2004 winter seasons* to snow cover anomalies from 1966 through the present
using monthly snow cover charts from Rutgers snow climatology web site (http://climate.rutgers.edu/snowcover/monthchart.html).
This comparison revealed the following consecutive winters with similar snow
cover anomalies, which act as the general set of analog matches: 1968-1969 and
1969-1970, 1977-1978 and 1978-1979, 1992-1993 and 1993-1994. (*Note: For
the purpose of this investigation, winter seasons consist of December, January
and February.)
2) Compared the Nino 3.4 sea surface temperature anomaly
for January through April of 2004 with the Nino 3.4 anomalies for January through
April of 1970, 1979 and 1994. This comparison revealed the year in which the
Nino 3.4 anomaly patterns most closely resembled that of 2004. This year was
1979.
