614
FOUS11 KWBC 250807
QPFHSD
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
407 AM EDT SUN OCT 25 2026
VALID 12Z SUN OCT 25 2026 - 12Z WED OCT 28 2026
..COLORADO
DAY 1...
AN UPPER LOW OVER NORTHERN ARIZONA WILL OPEN INTO A TROUGH AS IT
LIFTS NORTHEAST TO COLORADO THROUGH TODAY. HEIGHT FALLS WILL BRING
SNOW LEVELS DOWN TO AROUND 9000FT TODAY OVER CO TERRAIN. SHOWERY
ACTIVITY WILL LEAD TO ADDITIONAL ACCUMULATION. SNOW PROBS FOR >4
INCHES ADDITIONAL AFTER 12Z ARE 30-60% IN THE HIGHER SANGRE DE
CRISTO AND SAN JUAN MOUNTAINS.
..NORTHERN PLAINS
DAYS 2-3...
THE UPPER LOW CROSSING COLORADO TODAY WILL OPEN TO A TROUGH THAT
TAKES ON A NEGATIVE-TILT MONDAY AS IT LIFTS OVER THE NORTHERN
PLAINS. THE SURFACE LOW TRACK IS ACROSS KANSAS AND EASTERN
NEBRASKA MONDAY WITH ENOUGH COMMA HEAD PRECIP EXPANSION TO HAVE
SOME SNOW BANDS ON THE NORTHWEST SIDE OF THE PRECIP SHIELD. THIS
SHOULD INTERSECT WITH THE BLACK HILLS MONDAY ALONG WITH DYNAMIC
ENOUGH BANDING FOR SOME SNOW ACCUMULATION IN NORTHWESTERN SOUTH
DAKOTA AND SOUTH-CENTRAL NORTH DAKOTA. TEMPERATURES ARE MARGINAL,
BUT ANY SNOW THAT FALLS BEFORE SUNRISE WOULD HAVE A BETTER CHANCE
OF ACCUMULATING. MOST LIKELY FORECAST IS FOR A BROAD SWATH OF T-0.5"
SNOW WITH SOME POTENTIAL FOR AN AXIS OF 1-2" FROM THE BLACK HILLS
NORTHEASTWARD. DAY 2 WPC SNOW PROBABILITY OF AT LEAST 2" IS 20-30%
IN THE BLACK HILLS.
..CASCADES AND NORTHERN ROCKIES
DAYS 1-3...
AN UPPER LOW REACHES THE WA/OR COAST THIS AFTERNOON WITH A SERIES
OF REINFORCING SHORTWAVE TROUGHS MAINTAINING LOW PRESSURE OVER THE
NORTHWEST STATES FOR MUCH OF THE NEXT WEEK. SNOW LEVELS ARE
GENERALLY 6000FT IN THE CASCADES. A THERMAL GRADIENT IS APPARENT
OVER WEST-CENTRAL MT WITH SNOW LEVELS DOWN TO 3000FT EAST OF MT
TERRAIN AND AROUND 8000FT IN ID AND WY. DAY 1 SNOW PROBS FOR >6"
ARE 40-60% IN THE HIGHEST SOUTHERN WA AND OR CASCADES. DAY 2.5 SNOW
PROBS FOR >6" 30-50% FOR THE TETONS UP ALONG THE ID/MT BORDER
TERRAIN. DAY 3 SNOW PROBS FOR >6" ARE FARTHER NORTH OVER THE WA
CASCADES AND NORTH WEST MT RANGES IN/NEAR GLACIER NP.
FOR DAYS 1-3, THE PROBABILITY OF SIGNIFICANT ICE ACROSS THE CONUS
IS LESS THAN 10 PERCENT.
JACKSON
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