177
FXUS01 KWBC 140732
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
232 AM EST SAT DEC 14 2024
VALID 12Z SAT DEC 14 2024 - 12Z MON DEC 16 2024
...ATMOSPHERIC RIVER CONTINUES TO BRING VERY HEAVY RAIN WITH THE
POTENTIAL FOR FLOODING, HEAVY MOUNTAIN SNOW, AND GUSTY WINDS TO
CENTRAL/NORTHERN CALIFORNIA SATURDAY...
...HEAVY MOUNTAIN SNOW FORECAST FOR PORTIONS OF THE GREAT BASIN
AND NORTHERN ROCKIES SATURDAY...
...WINTRY MIX INCLUDING ACCUMULATING FREEZING RAIN CONTINUES FOR
PORTIONS OF THE UPPER MIDWEST SATURDAY, SPREADING INTO THE CENTRAL
APPALACHIANS SUNDAY...
A PACIFIC STORM SYSTEM AND ACCOMPANYING STRONG FLOW OF
MOISTURE/ATMOSPHERIC RIVER CONTINUES INLAND OVER THE WEST THIS
MORNING (SATURDAY) BRINGING HEAVY RAINFALL, MOUNTAIN SNOW, AND
GUSTY WINDS TO CENTRAL/NORTHERN CALIFORNIA AND THE PACIFIC
NORTHWEST. THE HEAVIEST RAINFALL WILL CONTINUE TO FOCUS ON
PORTIONS OF CENTRAL/NORTHERN CALIFORNIA THROUGH SATURDAY MORNING
WHERE RAINFALL RATES OF 0.5" TO 1" PER HOUR WILL LEAD TO AN
ADDITIONAL FEW INCHES OF RAINFALL OVER ALREADY SATURATED GROUND.
THE GREATEST POTENTIAL FOR FLOODING WILL BE AROUND THE GREATER BAY
AREA WHERE A SLIGHT RISK OF EXCESSIVE RAINFALL (LEVEL 2/4) IS IN
EFFECT. HEAVY SNOWFALL WILL ALSO CONTINUE FOR HIGHER MOUNTAIN
ELEVATIONS OF THE COASTAL RANGES AND SIERRA NEVADA, GENERALLY OVER
5000 FEET, WHERE WINTER STORM WARNINGS HAVE BEEN ISSUED FOR STORM
TOTAL SNOWFALL OF 1-3 FEET. WINTER WEATHER ADVISORIES ARE ALSO IN
EFFECT FURTHER NORTH INTO THE CASCADES WHERE STORM TOTAL SNOWFALL
OF 8-12", LOCALLY 18", CAN BE EXPECTED. GUSTY WINDS ALSO CONTINUE
THIS MORNING, PARTICULARLY ALONG THE COAST, BUT ALL HAZARDOUS
IMPACTS FROM THE SYSTEM SHOULD BEGIN TO TAPER OFF THROUGH SATURDAY
AFTERNOON.
THE SYSTEM WILL PUSH FURTHER INLAND THROUGH THE DAY SATURDAY,
SPREADING MOISTURE AND PRECIPITATION CHANCES ACROSS THE GREAT
BASIN AND NORTHERN ROCKIES. A MIX OF RAIN AND SNOW CAN BE EXPECTED
AT LOWER ELEVATIONS, THOUGH ANY SNOW ACCUMULATIONS SHOULD REMAIN
LIMITED. HEAVIER SNOW IS FORECAST IN THE MOUNTAINS, PARTICULARLY
FROM CENTRAL IDAHO INTO WESTERN WYOMING, WHERE WINTER STORM
WARNINGS ARE IN EFFECT FOR SNOWFALL OF 5-10", LOCALLY 12"+.
PRECIPITATION CHANCES WILL SPREAD EASTWARD INTO THE NORTHERN HIGH
PLAINS BY SATURDAY NIGHT WITH A WINTRY MIX EXPECTED. SOME LIGHT
ICE ACCRETIONS WILL BE POSSIBLE THROUGH THE DAY SUNDAY. SOME GUSTY
WINDS ARE ALSO LIKELY ALONG THE FRONT RANGE OF THE ROCKIES AS THE
SYSTEM PUSHES OUT ONTO THE PLAINS.
FURTHER EAST, AN UPPER-LEVEL SHORTWAVE/ACCOMPANYING SURFACE
FRONTAL SYSTEM WILL HELP TO TRIGGER SHOWERS AND THUNDERSTORMS
ACROSS THE OHIO, MIDDLE MISSOURI, AND LOWER MISSISSIPPI VALLEYS
SATURDAY, WITH SOME MODERATE TO LOCALLY HEAVY RAINFALL POSSIBLE.
STORMS WILL LIKELY LINGER INTO SUNDAY ALONG A TRAILING FRONTAL
BOUNDARY, THOUGH WITH LIGHTER AMOUNTS EXPECTED. MORE IMPACTFUL
WEATHER WILL CONTINUE FURTHER NORTH AS WARMER, MOIST AIR OVERRIDES
COLDER AIR AT THE SURFACE LEADING TO A WINTRY MIX ACROSS THE UPPER
MIDWEST AND GREAT LAKES. SNOW/SLEET ACCUMULATIONS SHOULD REMAIN
LIGHT, BUT FREEZING RAIN IS ALSO EXPECTED, PARTICULARLY OVER
EASTERN IOWA. AN ICE STORM WARNING REMAINS IN EFFECT THROUGH
SATURDAY AFTERNOON FOR TOTALS POTENTIALLY EXCEEDING 0.25" AND
LEADING TO TREE AND POWER LINE DAMAGE. THE SYSTEM WILL CONTINUE
EAST ON SUNDAY BRINGING A WINTRY MIX INTO THE SOUTHERN
APPALACHIANS. SIMILAR TO SATURDAY, SNOW/SLEET ACCUMULATIONS SHOULD
GENERALLY REMAIN LIGHT, BUT SOME ICE ACCRETIONS OVER 0.1" WILL BE
POSSIBLE.
ELSEWHERE, SOME SHOWERS AND THUNDERSTORMS CAN BE EXPECTED THIS
WEEKEND ALONG THE ATLANTIC COAST OF THE SOUTHEAST AND FLORIDA WITH
A QUASI-STATIONARY FRONTAL BOUNDARY IN PLACE. ADDITIONALLY, AFTER
A BRIEF BREAK LATE SATURDAY/EARLY SUNDAY, ANOTHER SYSTEM OVER THE
PACIFIC WILL BRING INCREASING PRECIPITATION CHANCES BACK TO THE
PACIFIC NORTHWEST BY SUNDAY EVENING. MOST OF THE COUNTRY WILL SEE
HIGH TEMPERATURES AT OR ABOVE AVERAGE THIS WEEKEND AS CONDITIONS
MODERATE FOLLOWING A COLD FRONTAL PASSAGE ACROSS THE SOUTH AND
WITH AN UPPER-LEVEL RIDGE PASSING OVER THE CENTRAL/WESTERN U.S.
AHEAD OF THE NEXT PACIFIC SYSTEM. SOME OF THE WARMEST TEMPERATURES
WILL BE IN THE SOUTHERN PLAINS/TEXAS WITH HIGHS IN THE 60S, 70S,
AND EVEN SOME LOW 80S. OTHERWISE, TEMPERATURES GENERALLY RANGE
FROM THE 30S AND 40S FROM THE PACIFIC NORTHWEST AND GREAT BASIN
EAST THROUGH THE NORTHERN PLAINS, GREAT LAKES, AND NORTHEAST; THE
50S AND 60S FOR CALIFORNIA, THE CENTRAL PLAINS, OHIO VALLEY, AND
THE SOUTH; AND 70S FOR THE DESERT SOUTHWEST AND FLORIDA.
PUTNAM
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