842
FOUS11 KWBC 241921
QPFHSD
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
321 PM EDT SAT OCT 24 2026
VALID 00Z SUN OCT 25 2026 - 00Z WED OCT 28 2026
..COLORADO
DAY 1...
AN UPPER LOW OVER NORTHWESTERN ARIZONA THIS EVENING WILL LIFT
NORTHEASTWARD ACROSS THE FOUR CORNERS OVERNIGHT. SOUTHERLY FLOW IN
ADVANCE OF THE LOW WILL BRING MODERATE PRECIP RATES AND HIGH SNOW
LEVELS OVER COLORADO AROUND 9000FT TONIGHT AS RATES DECREASE UNDER
HEIGHT FALLS. THE PROBABILITIES FOR AN ADDITIONAL 6 INCHES OF SNOW
AFTER 00Z ARE HIGHEST IN THE HIGHER SANGRE DE CRISTOS AND
ESPECIALLY THE HIGHER SAN JUAN MOUNTAINS.
..NORTHERN PLAINS
DAYS 2-3...
THE FOUR CORNERS LOW WILL MOSTLY OPEN TO A TROUGH BY MONDAY AND
EJECT ACROSS THE NORTHERN PLAINS. WITH SURFACE LOW PRESSURE MOVING
ACROSS EASTERN SD MONDAY NIGHT, ENOUGH COMMA HEAD EXPANSION OF
PRECIP SHOULD OCCUR TO HAVE SOME SNOW BANDS ON THE OUTER NORTHWEST
SIDE OF THE PRECIP SHIELD. THIS COULD INTERSECT WITH THE BLACK
HILLS AND COULD ALSO HAVE 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 T-0.5" SNOW WITH SOME POTENTIAL FOR AN AXIS
OF 1-2" FROM THE BLACK HILLS NORTHEASTWARD. THE PROBABILITY OF AT
LEAST 2" FROM THE PROBABILISTIC PRECIPITATION PORTAL IS ABOUT
20-55% ALONG THE ND/SD BORDER SOUTHWEST OF BISMARCK, BUT THE 90TH
PERCENTILE IS AROUND 4".
..NORTHERN ROCKIES
DAY 3...
AN UPPER LOW ALONG THE WA/OR COAST MONDAY WILL PUSH INLAND AND
CROSS THE DIVIDE EARLY TUESDAY, SPREADING VALLEY RAIN AND MOUNTAIN
SNOW TO WYOMING, IDAHO, AND WESTERN MONTANA. SNOW LEVELS WILL HOVER
AROUND 5000-7000FT THROUGH TUESDAY EVENING WITH SNOW CONTINUING
INTO EARLY WEDNESDAY. THE PROBABILITY OF AT LEAST 6 INCHES OF SNOW
BY 00Z WEDNESDAY IS >50% ABOVE ABOUT 8000FT WHERE LIQUID AMOUNTS
WILL BE HIGHEST AS WELL.
FOR DAYS 1-3, THE PROBABILITY OF SIGNIFICANT ICE ACROSS THE CONUS
IS LESS THAN 10 PERCENT.
FRACASSO/JACKSON
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