800
FXUS01 KWBC 112000
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 PM EST WED DEC 11 2024
VALID 00Z THU DEC 12 2024 - 00Z SAT DEC 14 2024
...HEAVY LAKE-ENHANCED SNOW DOWNWIND FROM THE GREAT LAKES ON
WEDNESDAY EVENING INTO THURSDAY; LIGHT LAKE-EFFECT SNOW DOWNWIND
FROM MOST OF THE GREAT LAKES ON FRIDAY; LIGHT TO MODERATE SNOW
OVER PARTS OF THE SIERRA NEVADA MOUNTAINS ON WEDNESDAY INTO
FRIDAY...
...MODERATE TO HEAVY LAKE-EFFECT SNOW DOWNWIND FROM LAKE ONTARIO
ON FRIDAY...
...TEMPERATURES WILL BE 15 TO 25 DEGREES BELOW AVERAGE OVER PARTS
OF THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY...
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PARTS OF NEW
ENGLAND...
A DEEP UPPER-LEVEL TROUGH OVER THE UPPER MIDWEST TO THE
MID-ATLANTIC WEAKENS SLIGHTLY WHILE UPPER-LEVEL ENERGY CONTINUES
TO MOVE ACROSS THE GREAT LAKES THROUGH FRIDAY. THE SYSTEM WILL
PRODUCE HEAVY LAKE-ENHANCED SNOW DOWNWIND FROM THE GREAT LAKES
WEDNESDAY EVENING INTO THURSDAY. OVERNIGHT THURSDAY INTO FRIDAY,
THE LAKE-ENHANCED SNOW WILL BECOME LIGHT LAKE-EFFECT SNOW DOWNWIND
FROM MOST OF THE GREAT LAKES. HOWEVER, MODERATE TO HEAVY
LAKE-EFFECT SNOW WILL DEVELOP DOWNWIND FROM LAKE ONTARIO ON FRIDAY.
ADDITIONALLY, A FRONT ALONG THE NORTHEAST COAST WILL MOVE QUICKLY
OUT OVER THE WESTERN ATLANTIC BY LATE WEDNESDAY NIGHT. RAIN WILL
DEVELOP ALONG THE BOUNDARY OVER MOST OF THE EAST COAST, ENDING
FROM THE MID-ATLANTIC SOUTHWARD OVERNIGHT WEDNESDAY. OVER NEW
ENGLAND, THE RAIN WILL CHANGE OVER TO LIGHT SNOW OVERNIGHT
WEDNESDAY INTO THURSDAY. THE SYSTEM WILL PRODUCE HEAVY RAIN OVER
PARTS OF NEW ENGLAND. THEREFORE, THE WPC HAS ISSUED A SLIGHT RISK
(LEVEL 2/4) OF EXCESSIVE RAINFALL OVER PARTS OF NEW ENGLAND
THROUGH THURSDAY MORNING. THE ASSOCIATED HEAVY RAIN WILL CREATE
MAINLY LOCALIZED AREAS OF FLASH FLOODING, WITH URBAN AREAS, ROADS,
SMALL STREAMS, AND LOW-LYING AREAS THE MOST VULNERABLE.
ON WEDNESDAY, HIGH PRESSURE OVER CENTRAL CANADA WILL MOVE
SOUTHEASTWARD TO THE GREAT LAKES AND MID-ATLANTIC BY FRIDAY
EVENING. COLD AIR ASSOCIATED WITH THE HIGH WILL MOVE OVER THE
UPPER MIDWEST, BRINGING TEMPERATURES 15 TO 25 DEGREES BELOW
AVERAGE OVER PARTS OF THE NORTHERN PLAINS AND UPPER MISSISSIPPI
VALLEY. THE COLD WEATHER HAS PROMPTED COLD WEATHER ADVISORIES OVER
PARTS OF NORTH DAKOTA, MINNESOTA, AND WISCONSIN.
MEANWHILE, ANOTHER FRONT OVER THE EASTERN PACIFIC WILL MOVE
ONSHORE OVER CALIFORNIA BY EARLY THURSDAY, DISSIPATING AS THE
BOUNDARY MOVES FROM SOUTHERN CALIFORNIA INTO MEXICO OVERNIGHT
THURSDAY. THE SYSTEM WILL PRODUCE COASTAL RAIN AND HIGHER
ELEVATION SNOW OVER PARTS OF THE PACIFIC NORTHWEST AND NORTHERN
CALIFORNIA OVERNIGHT WEDNESDAY INTO THURSDAY. ON THURSDAY, THE
RAIN AND HIGHER-ELEVATION SNOW WILL MOVE INTO CENTRAL CALIFORNIA,
PRODUCING LIGHT SNOW OVER THE SIERRA NEVADA MOUNTAINS OVER THE
NEXT FEW DAYS.
ON FRIDAY, ANOTHER FRONT OVER THE EASTERN PACIFIC WILL MOVE
ONSHORE OVER PARTS OF THE NORTHWEST AND CALIFORNIA. THE STORM WILL
PRODUCE MORE COASTAL RAIN AND HIGHER-ELEVATION SNOW OVER PARTS OF
THE PACIFIC NORTHWEST AND NORTHERN CALIFORNIA.
ELSEWHERE, RETURN FLOW OFF THE WESTERN GULF OF MEXICO WILL PRODUCE
LIGHT RAIN OVER PARTS OF THE WESTERN GULF COAST ON FRIDAY.
ZIEGENFELDER
GRAPHICS AVAILABLE AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP
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