215
FXUS01 KWBC 232034
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
333 PM EST TUE DEC 23 2025
VALID 00Z WED DEC 24 2025 - 00Z FRI DEC 26 2025
...STRONG ATMOSPHERIC RIVER BRINGS HEAVY RAIN, SNOW, AND WIND TO
CALIFORNIA THROUGH FRIDAY...
...MODERATE TO HEAVY SNOW CONTINUES OVER NEW ENGLAND TODAY;
FREEZING RAIN POSSIBLE ALONG THE NORTHERN TIER THURSDAY...
...UNSEASONABLE WARMTH FORECAST FOR MUCH OF THE LOWER 48 THROUGH
CHRISTMAS DAY...
ACROSS THE LOWER 48, MUCH OF OUR WEATHER PATTERN REMAINS DOMINATED
BY AN ANOMALOUS UPPER-RIDGE ANCHORED OVER THE NATION'S HEARTLAND
AND A HIGHLY AMPLIFIED TROUGH UPSTREAM OVER THE EASTERN PACIFIC.
THIS CONFIGURATION IS EXPECTED TO PERSIST THROUGH THE END OF THE
WORK WEEK, IN TURN SUPPORTING DANGEROUS ATMOSPHERIC RIVER
CONDITIONS ACROSS CALIFORNIA THROUGH FRIDAY. TO ADDRESS THE HEAVY
RAINFALL FORECAST FIRST, THE THREAT OF PARTICULARLY HEAVY RAINFALL
IS EXPECTED TO INCREASE OVER SOUTHERN CALIFORNIA (INCLUDING THE
LOS ANGELES METRO) LATE TONIGHT AHEAD OF A DEEPENING LOW PRESSURE
WAVE. BY TOMORROW MORNING, A RARE HIGH RISK OF EXCESSIVE RAINFALL
IS IN EFFECT FOR SOUTHERN CALIFORNIA, WHERE WIDESPREAD 4-7"
RAINFALL TOTALS (LOCALLY UPWARDS OF 9") IS EXPECTED OVER AN 18
HOUR TIME PERIOD. REMEMBER, WPC HIGH RISK DAYS ARE A BIG DEAL: 80%
OF ALL FLOOD RELATED DAMAGES AND 30% OF ALL FLOOD RELATED
FATALITIES OCCUR IN HIGH RISK AREAS. USERS IN THESE AREAS ARE
ENCOURAGED TO REMAIN VIGILANT AS LANDSLIDES, ROCKFALLS, AND
MUDSLIDES ARE ALSO ANTICIPATED OVER PORTIONS OF THE TRANSVERSE
RANGE. OUTSIDE OF THE HIGH RISK, SURROUNDING AREAS IN
CENTRAL/NORTHERN CALIFORNIA (INCLUDING SAN FRANCISCO AND SAN
DIEGO) AND SOUTHERN NEVADA (INCLUDING LAS VEGAS) CAN ALSO EXPECT
SCATTERED FLASH FLOODING THROUGH FRIDAY. IN THE MOUNTAINS OF THE
SIERRA NEVADA, SNOWFALL WILL BE MEASURED IN FEET AS PROLONGED
HEAVY SNOWFALL INCREASES TONIGHT AND SNOW LEVELS FALL FOLLOWING A
FRONTAL PASSAGE. ACCORDINGLY, TRAVEL THROUGH MOUNTAIN PASSES WILL
QUICKLY BECOME IMPOSSIBLE AS BLOWING SNOW BEGINS TO PILE UP.
IMPACTFUL WIND IS ALSO EXPECTED IN NEIGHBORING COASTAL AND
MOUNTAIN AREAS, WHICH WILL DRIVE WIDESPREAD POWER OUTAGES AND TREE
DAMAGE.
ON THE OPPOSITE COAST, MODERATE TO HEAVY SNOWFALL IS EXPECTED TO
OVERSPREAD NEW ENGLAND TONIGHT AHEAD OF AN OCCLUDED LOW PRESSURE
SYSTEM. MODERATE TO LOCALLY MAJOR WINTER STORM IMPACTS ARE
POSSIBLE WITH THIS EVENT OVER PORTIONS OF COASTAL MAINE TONIGHT,
WHERE 6-12 INCHES OF SNOW IS IN THE FORECAST. ADJACENT AREAS IN
THE ADIRONDACKS AND GREENS CAN EXPECT 3-7" THROUGH CHRISTMAS EVE,
WHERE A HANDFUL OF WINTER WEATHER ADVISORIES ARE IN EFFECT.
FREEZING RAIN IS A CONCERN ACROSS PORTIONS OF THE NORTHERN TIER ON
CHRISTMAS EVE AND CHRISTMAS AS MOISTURE FROM THE CALIFORNIA
ATMOSPHERIC RIVER INTERACTS WITH AN APPROACHING SHALLOW ARCTIC
AIRMASS, WITH UPWARDS OF A TENTH OF AN INCH POSSIBLE. TEMPERATURE
WISE, THE STRONG UPPER-RIDGE MEANS MUCH OF THE LOWER 48 CAN EXPECT
A VERY MILD CHRISTMAS WITH TEMPERATURES IN THE 70'S AND EVEN LOW
80'S FORECAST OVER THE SOUTHERN AND CENTRAL U.S. MUCH OF THE
SUB-FREEZING TEMPERATURES WILL BE RELEGATED TO THE NORTHERN TIER,
WHERE THE AFOREMENTIONED FREEZING RAIN IS POSSIBLE. EVEN SO, FOR
THIS TIME OF YEAR, THOSE TEMPERATURES ARE 10-15 DEGREES ABOVE
AVERAGE.
ASHERMAN
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