West Virginia exhibits a complex mosaic of soil climate regimes. Its unique geographic position at the intersection of continental and maritime weather fronts, and the orographic effects of its complex dissected mountainous terrain yield a range of soil moisture and temperature conditions. In the next generation of soil survey updates for West Virginia, the availability of digital elevation models (at 30m resolution) provides the base to apply terrain regressions that describe the functional relationships of latitude, longitude, elevation, slope gradient, and slope aspect to soil climate characteristics. The terrain regressions quantify the variation in lapse rates across soil landscapes, describe the strength of orographic processes, and identify the boundaries of rain shadows. A terrain regression modeling approach in ArcGIS was coupled with the Newhall Simulation Model (NSM; Van Wambeke et. al., 1992) to generate surfaces of soil temperature and moisture regimes, soil biological windows, and agroclimatic parameters (growing degree-days, frost-free period, and temperature minima). Initially, maps were developed based upon 1971 to 2000 normals. Later, long-term (>60 y) weather stations in West Virginia and surrounding states were modeled on individual years to build frequencies of soil climate regimes and droughts, as well as identify shifts in time and space. Agricultural and forest research locations in West Virginia and NOAA's Historical Climatology Network stations were used to identify shifts in soil temperature and moisture regimes through time. Based on the Newhall Simulation Model using 1971 to 2000 normals, the weather station at Snowshoe (elevation of 1454 m; 4770 ft) is the highest station location in West Virginia and classifies as having a cryic temperature regime and perudic moisture regime. In West Virginia, there are 11 weather stations that are perudic. The Pickens 1 (844 m; 2770 ft) and Snowshoe stations represent the two strongest (1061 mm and 974 mm, respectively, of annual water balance) perudic moisture regimes throughout the Central Appalachians. In contrast, Moorefield 1 SSE, located in the Valley and Ridge Province in the rain shadow of the Appalachians, receives only 835 mm (32.88 in), and has a mean annual water balance of 130 mm (~5 in). Soil biological window values (BIO5 and BIO8) derived from Newhall ranged from 185 days at Snowshoe to 268 days at Williamson, WV. Previous work by Soil Survey Staff (1994) showed some limited areas of frigid soil temperature regimes at the highest elevation in West Virginia. Our terrain regressions, based upon 1971 to 2000 normals, indicates more extensive areas of frigid temperatures and predicts cryic temperatures above elevations of 1378m (4200 ft). Nine cooperative weather stations classified as having thermic regimes; however, these stations were constrained to river valley positions near the Kentucky-Ohio-West Virginia border, and may represent urban thermal islands. Based upon our population of NWS cooperative weather stations, mean annual soil temperature (MAST) can be predicted by:

MAST = 90.3 -1.36 (Latitude) – 0.246 (Longitude) – 0.00271 (Elevation)

where latitude and longitude are expressed in decimal degrees, geographic coordinate system (NAD83), and elevation is expressed in feet. This research has implications for soil classification, and for agronomy and forestry interpretations. Our geospatial analyses will help guide correlation in soil survey update and maintenance.