634
FXUS01 KWBC 230754
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
254 AM EST TUE DEC 23 2025
VALID 12Z TUE DEC 23 2025 - 12Z THU DEC 25 2025
...THERE IS A HIGH RISK OF EXCESSIVE RAINFALL OVER PARTS OF
SOUTHERN CALIFORNIA ON WEDNESDAY...
..MODERATE TO HEAVY SNOW OVER THE NORTHEAST
...RAIN/FREEZING RAIN POSSIBLE OVER THE PENNSYLVANIA AND GREAT
LAKES...
A SYSTEM OVER THE GREAT LAKES TO THE CENTRAL PLAINS AND THEN
NORTHWESTWARD TO THE NORTHERN ROCKIES WILL MOVE OFF THE NORTHEAST
COAST BY TUESDAY NIGHT. MOISTURE STREAMING NORTHWARD OUT OF THE
GULF WILL AID IN DEVELOPING RAIN OVER PARTS OF THE OHIO/TENNESSEE
VALLEYS AND THE MID-ATLANTIC THROUGH TUESDAY AFTERNOON. THE RAIN
WILL THEN CONCENTRATE OVER THE TENNESSEE VALLEY, TUESDAY EVENING
THROUGH WEDNESDAY MORNING.
IN ADDITION, MODERATE TO HEAVY SNOW WILL DEVELOP OVER THE
NORTHEAST TUESDAY THROUGH WEDNESDAY MORNING. FURTHERMORE, ALONG
THE RAIN/SNOW LINE IN PENNSYLVANIA AND PARTS OF THE CENTRAL
APPALACHIANS, AREAS OF RAIN/FREEZING RAIN WILL DEVELOP OVER THE
REGION ON TUESDAY EVENING.
BY WEDNESDAY EVENING, A WAVE OF LOW PRESSURE WILL DEVELOP OVER
PARTS OF THE UPPER/MIDDLE MISSISSIPPI VALLEY AND MOVE EASTWARD
INTO THE OHIO VALLEY/CENTRAL APPALACHIANS BY THURSDAY MORNING. THE
SYSTEM WILL PRODUCE RAIN OVER PARTS OF THE OHIO VALLEY, MOVING
INTO PARTS OF THE MID-ATLANTIC BY CHRISTMAS MORNING. ALONG THE
NORTHERN EDGE OF THE PRECIPITATION SHIELD, POCKETS OF
RAIN/FREEZING RAIN WILL DEVELOP OVER PARTS OF THE GREAT LAKES AND
NORTHERN MID-ATLANTIC OVERNIGHT CHRISTMAS EVE INTO CHRISTMAS DAY.
MOREOVER, A DEVELOPING FRONT OVER EASTERN CANADA WILL ADVANCE TO
NEAR THE NORTHEAST BY CHRISTMAS MORNING, PRODUCING LIGHT SNOW OVER
NORTHERN NEW ENGLAND.
MEANWHILE, MOISTURE AND UPPER-LEVEL IMPULSES FROM THE PACIFIC WILL
STREAM EASTWARD OVER THE PACIFIC NORTHWEST/NORTHERN CALIFORNIA,
AHEAD OF A FRONT MOVING ONSHORE OVER THE WEST COAST BY WEDNESDAY
MORNING. THE SYSTEM WILL PRODUCE RAIN AND HIGHERÂELEVATION SNOW
OVER PARTS OF THE PACIFIC NORTHWEST AND THE NORTHERN INTERMOUNTAIN
REGION.
ALSO, ON TUESDAY, A BROAD PLUME OF MOISTURE WILL MOVE OVER
CALIFORNIA, WITH RAIN MOVING INTO SOUTHERN CALIFORNIA AND THE
GREAT BASIN OVERNIGHT. TWO AREAS OF HEAVY RAIN WILL DEVELOP OVER
NORTHERN/CENTRAL CALIFORNIA AND OVER SOUTHERN CALIFORNIA.
THEREFORE, THE WPC HAS ISSUED A SLIGHT RISK (LEVEL 2/4) OF
EXCESSIVE RAINFALL OVER PARTS OF NORTHERN/CENTRAL CALIFORNIA AND
SOUTHERN CALIFORNIA THROUGH WEDNESDAY MORNING. THE ASSOCIATED
HEAVY RAIN WILL CREATE MAINLY LOCALIZED AREAS OF FLASH FLOODING,
WITH URBAN AREAS, ROADS, SMALL STREAMS, AND BURN SCARS BEING THE
MOST VULNERABLE.
HEAVY SNOW WILL DEVELOP OVER THE SIERRA NEVADA MOUNTAINS THROUGH
THURSDAY. RAIN AND THE HIGHEST ELEVATIONS NOW WILL DEVELOP OVER
THE GREAT BASIN AND THE SOUTHWEST AND MOVE INTO THE CENTRAL
ROCKIES BY THURSDAY.
A STREAM OF MOISTURE-LADEN AIR WILL STREAM INTO SOUTHERN
CALIFORNIA ON WEDNESDAY, DEVELOPING HEAVY RAIN OVER PARTS OF
SOUTHERN CALIFORNIA. THEREFORE, THE WPC HAS ISSUED A HIGH RISK
(LEVEL 4/4) OF EXCESSIVE RAINFALL OVER SOUTHERN CALIFORNIA ON
WEDNESDAY INTO THURSDAY MORNING. SEVERE, WIDESPREAD FLASH
FLOODING IS EXPECTED. IN ADDITION, AREAS THAT NORMALLY DO NOT
EXPERIENCE FLASH FLOODING WILL FLOOD. FURTHERMORE, LIVES AND
PROPERTY ARE IN GREAT DANGER. ADDITIONALLY, A SLIGHT RISK OF
EXCESSIVE RAINFALL WILL DEVELOP OVER NORTHERN/CENTRAL CALIFORNIA
AND INTO PARTS OF SOUTHERN NEVADA ON WEDNESDAY.
ZIEGENFELDER
GRAPHICS AVAILABLE AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP
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