421
FXUS01 KWBC 230709
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
208 AM EST MON DEC 23 2024
VALID 12Z MON DEC 23 2024 - 12Z WED DEC 25 2024
...HEAVY RAIN AND MOUNTAIN SNOW RETURNS TO THE WEST COAST REGION
MONDAY NIGHT...
...SHOWERS AND THUNDERSTORMS DEVELOPING OVER PORTIONS OF THE
SOUTH-CENTRAL STATES...
...RELATIVELY MILD CONDITIONS ACROSS THE MAJORITY OF THE COUNTRY
LEADING UP TO CHRISTMAS...
AN ACTIVE WEATHER PATTERN IS EXPECTED TO CONTINUE ACROSS THE WEST
COAST REGION AS AN ENERGETIC STORM TRACK ACROSS THE EASTERN
PACIFIC BRINGS IN MULTIPLE ROUNDS OF PRECIPITATION. AFTER A BRIEF
RESPITE MONDAY, THE NEXT ATMOSPHERIC RIVER EVENT ARRIVES ACROSS
NORTHERN CALIFORNIA AND WESTERN OREGON LATE MONDAY NIGHT AND INTO
TUESDAY. ALTHOUGH THE STORM SYSTEM WILL BE PROGRESSIVE OVERALL,
THERE WILL BE A DEEP SURGE OF MOISTURE AHEAD OF THE COLD FRONT
THAT WILL INTERSECT THE COASTAL TERRAIN AND THE WESTERN SLOPES OF
THE NORTHERN SIERRA NEVADA. RAINFALL TOTALS ON THE ORDER OF 2-4
INCHES, AND LOCALLY HIGHER, ARE LIKELY ACROSS THIS REGION THROUGH
TUESDAY EVENING. SNOW LEVELS WILL BE INITIALLY HIGH, BUT SHOULD
FALL SOME ONCE THE FRONT PASSES. THE HEAVIEST SNOW FROM THIS
EVENT SHOULD AFFECT THE HIGHEST TERRAIN OF THE CENTRAL AND
NORTHERN SIERRA NEVADA, WITH UP TO A FOOT OF ACCUMULATION POSSIBLE.
A LOW PRESSURE SYSTEM CROSSING THE GREAT LAKES REGION ON MONDAY
WILL PRODUCE A CORRIDOR OF MIXED WINTRY PRECIPITATION FROM
SOUTHERN MINNESOTA TO SOUTHERN LOWER MICHIGAN, AND MAINLY LIGHT TO
MODERATE SNOW TO THE NORTH ACROSS NORTHERN WISCONSIN AND INTO
NORTHERN MICHIGAN. WINTER WEATHER ADVISORIES ARE CURRENTLY IN
EFFECT FOR THOSE AREAS. THIS LOW REACHES THE NORTHEAST U.S.
CHRISTMAS EVE, WITH LIGHT SNOW MAINLY FOR INTERIOR PORTIONS.
FARTHER TO THE SOUTH ACROSS TEXAS, A SEPARATE SURFACE LOW
DEVELOPS, AND INCREASING SOUTHERLY FLOW FROM THE WESTERN GULF OF
MEXICO AHEAD OF THAT SYSTEM WILL FUEL THE DEVELOPMENT OF SCATTERED
TO NUMEROUS SHOWERS AND SOME THUNDERSTORMS FROM EASTERN TEXAS
NORTHWARD ACROSS MUCH OF ARKANSAS AND INTO SOUTHERN MISSOURI
THROUGH TUESDAY.
MUCH OF THE EAST COAST REGION WILL HAVE A VERY COLD START TO THE
HOLIDAY WEEK ON MONDAY, WITH AN ARCTIC SURFACE HIGH SLOWLY MOVING
EAST ACROSS THE REGION. THE COLDEST MORNING OF THE SEASON THUS
FAR IS EXPECTED FOR MOST OF THE MID-ATLANTIC AND NORTHEAST STATES,
FOLLOWED BY ANOTHER CHILLY DAY ON MONDAY, ALBEIT SLIGHTLY MILDER
COMPARED TO WHAT WAS OBSERVED ON SUNDAY. A FURTHER MODERATION
TREND IS EXPECTED GOING INTO CHRISTMAS EVE AS THE SURFACE HIGH
MOVES OFFSHORE AND MILDER AIR FROM THE OHIO VALLEY ADVECTS
EASTWARD ACROSS THE REGION. THE REMAINDER OF THE COUNTRY SHOULD
ENJOY GENERALLY ABOVE AVERAGE TEMPERATURES BY LATE DECEMBER
STANDARDS, PARTICULARLY ACROSS THE CENTRAL AND SOUTHERN PLAINS
WHERE DAYTIME HIGHS COULD BE 15-20 DEGREES ABOVE AVERAGE. THIS
WOULD EQUATE TO HIGHS WELL INTO THE 60S AND 70S FOR MUCH OF TEXAS.
HAMRICK
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