971
FOUS11 KWBC 151905
QPFHSD
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
305 PM EDT WED APR 15 2026
VALID 00Z THU APR 16 2026 - 00Z SUN APR 19 2026
..CASCADES
DAY 1...
POTENT MID-LEVEL LOW DROPS OVER WASHINGTON STATE THROUGH THIS
EVENING WITH THE LEADING COLD FRONT CURRENTLY OVER OR PUSHING INTO
NORTHERN CA THIS AFTERNOON. INSTABILITY SHOWERS IN ONSHORE FLOW
BRINGS SNOW FOR THE CENTRAL WA CASCADES SOUTH THROUGH THE OR
CASCADES INTO THURSDAY MORNING WHERE DAY 1 SNOW PROBS FOR >4" ARE
40-80% ABOVE THE SNOW LEVEL THAT DROPS TO AROUND 1500FT THROUGH THE
REST OF THIS AFTERNOON.
..NORTH TO CENTRAL ROCKIES AND CENTRAL HIGH PLAINS
DAYS 1-2...
THE MID-LEVEL LOW OPENS INTO A TROUGH OVER THE NORTHERN ROCKIES
EARLY THURSDAY WITH A NORTHERN PORTION SHIFTING EAST ALONG THE
CANADIAN BORDER AS A WEAKLY CLOSED LOW WHILE THE SOUTHERN PORTION
DIGS THROUGH THE GREAT BASIN BEFORE TURNING EAST ACROSS THE
CENTRAL ROCKIES FRIDAY. THE PRECEDING COLD FRONT PROVIDES A FOCUS
FOR SNOW OVER CENTRAL ID TERRAIN THIS AFTERNOON, SHIFTING TO
SOUTHERN ID/WESTERN WY TONIGHT. SNOW LEVELS OF 6000-7000FT MSL
AHEAD OF THE FRONT RAPIDLY DROP TO 2000-3000FT (SUBTERRANEAN)
BEHIND THE FRONT. DAY 1 SNOW PROBS FOR >6" ARE 40-80% IN CENTRAL ID
(VALUES REDUCED SINCE THE PROBS START AT 00Z IN ONGOING SNOW) AND
50-90% IN TERRAIN AROUND GREATER YELLOWSTONE INCLUDING THE TETONS
AND ABSAROKAS AS WELL AS THE WIND RIVER RANGE. THE PROGRESSION OF
THE FRONT AND SOUTHERN LOBE OF THE SPLIT TROUGH THROUGH THURSDAY
NIGHT BRINGS DAY 1.5 SNOW PROBS FOR >6" TO 60-90% FOR THE BIGHORNS
AND 40-70% FOR THE WASATCH AND UINTA.
THE MID-LEVEL TROUGH CROSSES CO ON FRIDAY PROVIDING MUCH WELCOME
SNOW TO WESTERN SLOPES OF THE NORTHERN/CENTRAL CO ROCKIES. DAY 2
SNOW PROBS FOR >6" ARE 40-70% FOR THE PARK AND FRONT RANGES.
NORTHERLY POST-FRONTAL FLOW BRINGS A LIGHT SNOW RISK TO THE DENVER
METRO FRIDAY AFTERNOON WHERE DAY 2 SNOW PROBS FOR >2" ARE 10-20%
FOR THE NORTHERN SIDE OF THE PALMER DIVIDE INTO THE FOOTHILLS WEST
OF DENVER.
AN ADDITIONAL NOTE, THE SHARP COLD FRONT SHOULD PRODUCE
CONVECTIVE SNOW BANDS OVER EASTERN OR/CENTRAL ID THIS AFTERNOON AND
SOUTHERN UT INTO CENTRAL WY THURSDAY AFTERNOON. THESE MAY BE STRONG
ENOUGH TO QUALIFY AS SNOW SQUALLS AND CAUSE HAZARDOUS DROPS IN
VISIBILITY AND FLASH FREEZE CONDITIONS ON ROADS.
..NORTHERN PLAINS
DAY 2...
THE STRONG COLD FRONT ASSOCIATED WITH THE LOW MOVING OVER THE
PACIFIC NORTHWEST THIS AFTERNOON WILL PUSH ONTO THE NORTHERN PLAINS
THURSDAY. AS THE UPPER TROUGH SPLITS AND DIGS DOWN THE GREAT BASIN
THURSDAY NIGHT, A TIGHTENING BAROCLINIC ZONE WITH ENHANCED SW FLOW
OVERHEAD WITH MOISTURE FROM THE SOUTHERN PLAINS/GULF WILL ALLOW
SNOW BANDS TO SET UP FIRST OVER THE BLACK HILLS/WESTERN SD THURSDAY
EVENING AND OVER EASTERN ND/NORTHWEST MN LATE THURSDAY NIGHT INTO
FRIDAY. MARGINAL THERMALS LOOK TO BE OVERCOME IN POTENT BANDING
FROM LOW LEVEL FGEN FORCING WITH MODERATE PRECIP RATES. 12Z
HRRR/3KMNAM IN AGREEMENT FOR A SUBFREEZING PROFILE IN THE BANDING
WITH POTENTIAL FOR A FEW INCHES OF SNOW. DAY 2 SNOW PROBS FOR >2"
ARE 40-60% FROM CENTRAL TO NORTHEASTERN ND AND THE NORTHWEST CORNER
OF MN. TO THE EAST OF THIS SNOW SWATH IS A RISK FOR ICE ACCRETION
SHOULD THE 2M TEMP REMAIN BELOW FREEZING. DAY 2 ICE PROBS FOR >0.1"
ARE 10-20% IN NORTHEAST ND AND ACROSS NORTHWEST MN.
JACKSON
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