711
FXUS01 KWBC 190801
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
301 AM EST TUE NOV 19 2024
VALID 12Z TUE NOV 19 2024 - 12Z THU NOV 21 2024
...POWERFUL PACIFIC LOW PRESSURE SYSTEM TO PRODUCE SIGNIFICANT
HIGH WIND IMPACTS AND HEAVY MOUNTAIN SNOW ACROSS THE NORTHWEST,
WHILE A STRONG ATMOSPHERIC RIVER TAKES AIM AT NORTHERN CALIFORNIA
BY WEDNESDAY...
...POTENT STORM SYSTEM OVER THE NORTHERN PLAINS TO PRODUCE GUSTY
WINDS AND LOCALLY HEAVY SNOW THROUGHOUT THE REGION BEFORE A
REDEVELOPING AREA OF LOW PRESSURE BRINGS UNSETTLED WEATHER TO THE
GREAT LAKES, CENTRAL APPALACHIANS, AND NORTHEAST FROM MIDWEEK
ONWARD...
...HEAVY RAIN AND FLASH FLOODING POTENTIAL CONTINUES THROUGHOUT
PORTIONS OF THE CENTRAL AND EASTERN GULF COAST TODAY...
NO SHORTAGE OF ACTIVE WEATHER ACROSS THE NATION THIS WEEK AS TWO
SEPARATE STRONG LOW PRESSURE SYSTEMS PRODUCE HAZARDOUS CONDITIONS
IN THE FORM OF HIGH WINDS, HEAVY RAIN, AND SNOWFALL. STARTING WITH
THE PACIFIC NORTHWEST, A RAPIDLY STRENGTHENING AND EXTREMELY
POWERFUL LOW PRESSURE SYSTEM FORECAST TO PASS ROUGHLY 300 MILES
WEST OF THE OLYMPIC PENINSULA TONIGHT IS ANTICIPATED TO BEGIN
IMPACTING THE REGION TODAY. DAMAGING WINDS WITH GUSTS UP TO 70 MPH
ARE POSSIBLE ACROSS NORTHERN CALIFORNIA, AS WELL AS PARTS OF
OREGON AND WASHINGTON, WITH THE HIGHEST WINDS EXPECTED ALONG THE
COAST AND HIGH TERRAIN. THESE WINDS ARE LIKELY TO PRODUCE NUMEROUS
POWER OUTAGES AND TREE DAMAGE IN THE MOST IMPACTED REGIONS. WHEN
COMBINED WITH HEAVY SNOWFALL AT THE HIGHER ELEVATIONS, BLIZZARD
CONDITIONS ARE IN THE FORECAST THROUGHOUT THE WASHINGTON CASCADES.
AS AN ASSOCIATED FRONTAL BOUNDARY SLIDES SOUTHEASTWARD AND STALLS
NEAR NORTHERN CALIFORNIA ON WEDNESDAY, A DEEP AND CONTINUOUS PLUME
OF ANOMALOUS ATMOSPHERIC MOISTURE CONTENT WILL FLOW INTO THE
REDWOOD COAST OF CALIFORNIA AND NORTHERN MOUNTAIN RANGES OF THE
GOLDEN STATE. HEAVY RAIN AND RISING SNOW LEVELS WILL INCREASE THE
THREAT OF NUMEROUS FLOODS AND POTENTIAL MUDSLIDES, EXACERBATED BY
THE DURATION OF HEAVY RAINFALL THROUGH THE END OF THE WEEK. IN
FACT, WPC HAS ISSUED A HIGH RISK (LEVEL 4/4) OF EXCESSIVE RAINFALL
ACROSS PARTS OF NORTHWEST CALIFORNIA ON THURSDAY IN ORDER TO
FURTHER HIGHLIGHT THIS FLOODING THREAT. RESIDENTS AND VISITORS
THROUGHOUT THE NORTHWEST ARE URGED TO HAVE MULTIPLE WAYS TO
RECEIVE WARNINGS, LISTEN TO ADVICE FROM LOCAL OFFICIALS, AND AVOID
TRAVELING THROUGH HAZARDOUS WEATHER CONDITIONS IF POSSIBLE.
IN THE NORTH-CENTRAL U.S. ANOTHER POTENT LOW PRESSURE SYSTEM IS
LIFTING NORTHWARD AND PRODUCING UNSETTLED WEATHER OF ITS OWN
ACROSS THE UPPER MIDWEST AND NORTHERN PLAINS TODAY. A TIGHT
PRESSURE GRADIENT BEING PRODUCED BY THE STORM IS FORECAST TO
CREATE STRONG WINDS ACROSS MUCH OF NEBRASKA, EASTERN MONTANA, AND
THE DAKOTAS THROUGH WEDNESDAY WITH MAXIMUM WIND GUSTS UP TO 65 MPH
POSSIBLE. STRONG WINDS MAY ALSO OVERLAP WITH MODERATE TO LOCALLY
HEAVY SNOW THROUGHOUT NORTH DAKOTA AND NORTHWEST MINNESOTA AS THE
STORM SYSTEM STALLS TONIGHT OVER SOUTH-CENTRAL CANADA.
PROBABILITIES FOR AT LEAST 6 INCHES OF TOTAL SNOWFALL ARE HIGH
(>70%) ACROSS NORTHERN NORTH DAKOTA. MEANWHILE, SCATTERED SHOWERS
ARE FORECAST TO SPREAD EASTWARD INTO THE MIDWEST, GREAT LAKES, AND
EVENTUALLY THE MID-ATLANTIC AHEAD OF AN ADVANCING COLD FRONT
TODAY. BY WEDNESDAY NIGHT, A REDEVELOPING LOW PRESSURE SYSTEM
RAPIDLY STRENGTHENING OVER THE GREAT LAKES WILL HELP PRODUCE
ANOTHER ROUND OF PRECIPITATION OVER THE GREAT LAKES, CENTRAL
APPALACHIANS AND NORTHEAST THROUGH THE END OF THE WEEK. THE
GREATEST IMPACTS FROM THIS PRECIPITATION IS EXPECTED THROUGHOUT
THE HIGHER ELEVATIONS OF WEST VIRGINIA AND WESTERN MARYLAND, WHERE
UP TO A FOOT OF SNOWFALL IS POSSIBLE THROUGH FRIDAY.
ELSEWHERE, HEAVY RAIN AND A RISK FOR SCATTERED FLASH FLOODS
REMAINS A CONCERN ACROSS THE CENTRAL AND EASTERN GULF COAST AS A
COLD FRONT, WEAK AREA OF LOW PRESSURE, AND AMPLE ATMOSPHERIC
MOISTURE CONTENT SPARK NUMEROUS SHOWERS AND THUNDERSTORMS CAPABLE
OF CONTAINING INTENSE RAINFALL RATES THROUGH TONIGHT. THE GREATEST
RISK FOR FLASH FLOODING SPECIFICALLY EXISTS FROM FAR EASTERN
LOUISIANA TO THE WESTERN FLORIDA PANHANDLE, WITH URBAN AND POOR
DRAINAGE REGIONS MOST SUSCEPTIBLE TO RAPID WATER RISES.
TEMPERATURES WILL BE ON A ROLLER COASTER RIDE THIS WEEK AS WELL
ABOVE AVERAGE TEMPERATURES ARE FOUND IN THE EAST BEFORE AN
ADVANCING COLD FRONT KNOCKS READINGS DOWN BELOW AVERAGE BY
THURSDAY. MEANWHILE, COOLER TEMPERATURES OVER MUCH OF THE WEST ARE
FORECAST TO RETURN TO NEAR NORMAL AS UPPER RIDGING BUILDS INTO
PLACE.
SNELL
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