049
FXUS01 KWBC 180747
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
347 AM EDT TUE APR 18 2023
VALID 12Z TUE APR 18 2023 - 12Z THU APR 20 2023
...SNOW OVER THE CASCADES ON TUESDAY AND WEDNESDAY; MODERATE SNOW
OVER PARTS OF THE NORTHERN PLAINS ON WEDNESDAY...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE CENTRAL/
SOUTHERN PLAINS INTO THE MIDDLE MISSISSIPPI VALLEY ON WEDNESDAY...
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PARTS OF
THE CENTRAL PLAINS, UPPER/MIDDLE MISSISSIPPI VALLEY, AND UPPER
GREAT LAKES ON WEDNESDAY...
ON TUESDAY, A FRONT EXTENDING FROM THE NORTHERN INTERMOUNTAIN
REGION TO CENTRAL CALIFORNIA WILL MOVE EASTWARD AND MERGE WITH A
WEAK FRONT OVER THE ROCKIES BY TUESDAY EVENING. THE FRONT WILL
CONTINUE TO MOVE EASTWARD TO MIDDLE MISSISSIPPI VALLEY AND
SOUTHWARD TO THE SOUTHERN HIGH PLAINS BY THURSDAY MORNING. ON
TUESDAY, THE SYSTEM WILL PRODUCE SNOW OVER PARTS OF THE NORTHERN
INTERMOUNTAIN REGION AND THE NORTHERN ROCKIES.
IN ADDITION, MOISTURE WILL FLOW NORTHWARD OVER THE
SOUTHERN/CENTRAL PLAINS INTO THE NORTHERN HIGH PLAINS. AS A
RESULT, ON TUESDAY, SHOWERS AND THUNDERSTORMS WILL START TO
DEVELOP OVER THE NORTHERN HIGH PLAINS. BY TUESDAY AFTERNOON,
SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER PARTS OF THE SOUTHERN
PLAINS. MOREOVER, OVERNIGHT TUESDAY, SHOWERS AND THUNDERSTORMS
WILL DEVELOP OVER PARTS OF THE NORTHERN/CENTRAL PLAINS INTO PARTS
OF THE MIDDLE MISSISSIPPI VALLEY. ALSO, OVERNIGHT TUESDAY, SNOW
WILL DEVELOP OVER PARTS OF THE NORTHERN HIGH PLAINS, BECOMING
LIGHT TO MODERATE ON WEDNESDAY.
ON WEDNESDAY, SHOWERS AND SEVERE THUNDERSTORMS WILL DEVELOP OVER
PARTS OF OKLAHOMA TO IOWA AS THE FRONT MOVES ONTO THE PLAINS.
THEREFORE, THE SPC HAS ISSUED A SLIGHT RISK OF SEVERE
THUNDERSTORMS OVER PARTS OF THE CENTRAL/SOUTHERN PLAINS INTO THE
MIDDLE MISSISSIPPI VALLEY FROM WEDNESDAY INTO THURSDAY MORNING.
THE HAZARDS ASSOCIATED WITH THESE THUNDERSTORMS ARE FREQUENT
LIGHTNING, SEVERE THUNDERSTORM WIND GUSTS, HAIL, AND A FEW
TORNADOES.
FURTHERMORE, MODERATE TO HEAVY RAIN WILL ACCOMPANY THE
THUNDERSTORMS OVER PARTS OF KANSAS NORTHWARD TO MINNESOTA AND
WISCONSIN. THEREFORE, THE WPC HAS ISSUED A MARGINAL RISK OF
EXCESSIVE RAINFALL OVER PARTS OF THE CENTRAL PLAINS, UPPER/MIDDLE
MISSISSIPPI VALLEY, AND UPPER GREAT LAKES FROM WEDNESDAY INTO
THURSDAY MORNING. THE ASSOCIATED HEAVY RAIN WILL CREATE LOCALIZED
AREAS OF FLASH FLOODING, AFFECTING AREAS THAT EXPERIENCE RAPID
RUNOFF WITH HEAVY RAIN. MOREOVER, SHOWERS AND THUNDERSTORMS WILL
MOVE INTO THE GREAT LAKES OVERNIGHT WEDNESDAY.
MEANWHILE, ON TUESDAY, WEAK ONSHORE FLOW AND UPPER-LEVEL ENERGY
WILL CREATE COASTAL RAIN AND HIGHER ELEVATION SNOW, IN THE
CASCADES, OVER THE PACIFIC NORTHWEST AND NORTHERN CALIFORNIA, WITH
SNOW EXTENDING INTO PARTS OF THE SIERRA NEVADA MOUNTAINS. HOWEVER,
THE SNOW OVER THE SIERRA NEVADA MOUNTAINS WILL BEGIN TO TAPER OFF
OVERNIGHT TUESDAY. IN CONTRAST, THE COASTAL RAIN AND
HIGHER-ELEVATION SNOW WILL CONTINUE OVER THE PACIFIC NORTHWEST
THROUGH LATE WEDNESDAY AFTERNOON AND BEGIN TO TAPER OFF ON
THURSDAY MORNING. ELSEWHERE, LAKE-EFFECT SNOW WILL DEVELOP
DOWNWIND OF THE GREAT LAKES ON TUESDAY INTO LATE TUESDAY EVENING.
ZIEGENFELDER
GRAPHICS AVAILABLE AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP
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