WESTERN SOUTH DAKOTA AND NORTHEASTERN WYOMING
2007-2008 WINTER OUTLOOK


SYNOPSIS…
THE OUTLOOK FOR DECEMBER THROUGH FEBRUARY CALLS FOR NEAR AVERAGE PRECIPITATION FOR MOST OF NORTHEASTERN WYOMING AND WESTERN SOUTH DAKOTA. TEMPERATURES ARE EXPECTED TO BE NEAR OR SLIGHTLY ABOVE AVERAGE. BASED ON THE PRESENT LA NINA CONDITIONS…THE OVERALL WEATHER PATTERN THIS WINTER WILL LIKELY PRODUCE MORE STORM SYSTEMS ORIGINATING OVER THE PACIFIC NORTHWEST. THESE SYSTEMS DO NOT PRODUCE MUCH PRECIPITATION OVER THE REGION AS MUCH OF THEIR MOISTURE FALLS OVER THE ROCKIES. THEY DO BRING MORE MILD PACIFIC AIR TO THE REGION…WHICH COULD REDUCE INTRUSTIONS OF COLD ARCTIC AIR. MODERATE TO POSSIBLY STRONG LA NINA CONDITIONS ARE EXPECTED THROUGH THE SPRING OF 2008. PREVIOUS WINTER SEASONS WITH SIMILAR LA NINA CONDITIONS HAVE BEEN REVIEWED…AS WELL AS YEARS WITH WEATHER PATTERNS LIKE THOSE OF THE SUMMER AND EARLY FALL MONTHS OF 2007. THESE WERE USED TO PREDICT THE OVERALL WEATHER PATTERN FOR THIS WINTER.

TEMPERATURE OUTLOOK…
WINTER TEMPERATURES WILL LIKELY BE NEAR OR SLIGHTLY ABOVE AVERAGE ACROSS NORTHEASTERN WYOMING AND WESTERN SOUTH DAKOTA. THIS HAS BEEN THE TREND OVER THE PAST SEVERAL WINTERS. HOWEVER…OCCASIONAL STRONG ARCTIC INTRUSIONS ARE POSSIBLE…WHICH WOULD MAINLY AFFECT CENTRAL SOUTH DAKOTA.

PRECIPITATION OUTLOOK…
PRECIPITATION WILL LIKELY BE NEAR AVERAGE ON THE PLAINS OF NORTHEASTERN WYOMING AND WESTERN SOUTH DAKOTA. SLIGHTLY ABOVE AVERAGE PRECIPITATION IS EXPECTED ACROSS THE BEAR LODGE MOUNTAINS…THE NORTHERN BLACK HILLS…AND THE NORTHERN FOOTHILLS AS MORE STORM SYSTEMS WOULD BRING UPSLOPE SNOWFALL TO THESE AREAS.

PRECIPITATION ON THE PLAINS OF NORTHEASTERN WYOMING AND WESTERN SOUTH DAKOTA FOR DECEMBER THROUGH FEBRUARY AVERAGES ABOUT 1 TO 2 INCHES…WHICH IS ONLY ABOUT 10 PERCENT OF THE ANNUAL AVERAGE. IN THE UPSLOPE AREAS OF THE NORTHERN BLACK HILLS AND BEAR LODGE MOUNTAINS…AVERAGE PRECIPITATION FOR THE WINTER SEASON IS 3 TO 5 INCHES.

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