045
FXUS01 KWBC 230800
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 AM EDT MON OCT 23 2023
VALID 12Z MON OCT 23 2023 - 12Z WED OCT 25 2023
...HEAVY RAIN CHANCES AND FLASH FLOOD POTENTIAL INCREASES ACROSS
THE SOUTHERN PLAINS EARLY THIS WEEK...
...SOME LOCALLY HEAVY RAINFALL POSSIBLE FOR THE UPPER GREAT LAKES
TUESDAY...
...IMPACTFUL SNOW TO ENTER PARTS OF THE NORTHWEST, NORTHERN
ROCKIES, AND NORTHERN HIGH PLAINS ON TUESDAY...
AFTER A GENERALLY QUIET PERIOD OF WEATHER FOR MUCH OF THE COUNTRY,
THE PATTERN GETS MORE ACTIVE THIS WEEK INCLUDING A COUPLE REGIONS
OF LOCALLY HEAVY RAINFALL WITH FLASH FLOOD POTENTIAL AND AN EARLY
SEASON WINTER STORM. AN INITIAL UPPER-LEVEL LOW DROPPING WELL
SOUTHWARD INTO NORTHERN MEXICO AS A RIDGE AMPLIFIES OVER THE
SOUTHEAST WILL HELP TO FOCUS SOUTHERLY FLOW OVER THE SOUTHERN
PLAINS. THE POTENT UPPER-LEVEL DYNAMICS AS WELL AS AMPLE MOISTURE
ADVECTING NORTHWARD, ENHANCED BY THE REMNANTS OF NORMA FROM THE
EASTERN PACIFIC, ARE EXPECTED TO TRIGGER NUMEROUS SHOWERS AND
THUNDERSTORMS FROM THE TEXAS BIG BEND VICINITY NORTHEASTWARD
THROUGH NORTHWEST TEXAS INTO OKLAHOMA AND EASTERN KANSAS MONDAY
AND TUESDAY. SLIGHT RISKS FOR EXCESSIVE RAINFALL (LEVEL 2/4) ARE
IN EFFECT BOTH DAYS AS THE ANOMALOUSLY HIGH MOISTURE, AS WELL AS
THE STAGNANT PATTERN WITH STORMS REPEATING OVER THE SAME AREA,
WILL LEAD TO THE THREAT OF LOCALLY HEAVY DOWNPOURS/RAINFALL TOTALS
AND THE RISK OF SOME SCATTERED FLASH FLOODING. RAIN CHANCES LOOK
TO CONTINUE THIS WEEK BEYOND THE CURRENT FORECAST PERIOD AS THE
UPPER LOW IS FORECAST TO PROGRESS SLOWLY AND A STORMY PATTERN
REMAINS IN PLACE. HIGH TEMPERATURES WILL GENERALLY BE ABOVE
AVERAGE FROM THE SOUTHERN PLAINS INTO THE SOUTHEAST UNDER THE
INFLUENCE OF THE UPPER-LEVEL RIDGE, WITH 70S AND 80S FORECAST.
TEMPERATURES WILL BE AROUND AVERAGE TO THE WEST UNDER THE
UPPER-LOW, WITH 60S AND 70S FOR CALIFORNIA AND THE GREAT BASIN AND
80S FOR THE DESERT SOUTHWEST.
MEANWHILE, FURTHER NORTH, SOME LIGHTER SHOWERS ARE EXPECTED MONDAY
ALONG A COLD FRONT PUSHING SOUTHWARD ACROSS THE NORTHERN PLAINS
AND UPPER GREAT LAKES. AS THE NOTED BROAD SOUTHERLY FLOW OVER THE
PLAINS HELPS TO ADVECT MORE MOISTURE NORTHWARD, SOME MORE POTENT
STORMS WILL LOCALLY HEAVY DOWNPOURS ARE POSSIBLE TUESDAY FOR
PORTIONS OF THE UPPER GREAT LAKES, WITH AN ISOLATED RISK OF FLASH
FLOODING. TEMPERATURES WILL BE RUNNING AS MUCH AS 10 TO 20 DEGREES
ABOVE AVERAGE AHEAD OF THE FRONT, WITH THE ANOMALIES CENTERED ON
THE CENTRAL PLAINS MONDAY AND THE MISSISSIPPI VALLEY INTO GREAT
LAKES TUESDAY. HIGHS WELL INTO THE 80S AND EVEN A SHOT AT 90 ARE
POSSIBLE FOR THE CENTRAL PLAINS MONDAY.
TO THE WEST, SOME RAIN AND HIGHER ELEVATION, MOUNTAIN SNOW IS
EXPECTED ALONG THE FRONTAL BOUNDARY AS IT EXTENDS INTO THE
NORTHERN ROCKIES MONDAY. THEN, ANOTHER UPPER-LEVEL SYSTEM UPSTREAM
OVER THE NORTHEASTERN PACIFIC WILL DROP SOUTHWARD TUESDAY,
ENHANCING PRECIPITATION CHANCES ALONG AND BEHIND THE FRONTAL
BOUNDARY. THIS WILL ALSO BRING MUCH COLDER AIR SOUTHWARD, DROPPING
SNOW LEVELS AND LEAD TO AN EARLY SEASON WINTER STORM BEGINNING IN
THE NORTHWEST AND NORTHERN ROCKIES BY LATE TUESDAY. THIS STORM
WILL CONTINUE BEYOND THE CURRENT FORECAST PERIOD, AND SPREAD
FURTHER EASTWARD INTO THE NORTHERN HIGH PLAINS BY WEDNESDAY.
WINTER STORM WATCHES ARE OUT FOR PORTIONS OF THE CASCADES AND
NORTHERN ROCKIES AS STORM TOTAL SNOW OF 8-12" WILL BE POSSIBLE.
SNOW LEVELS WILL DROP OVERNIGHT TUESDAY, ALLOWING RAIN TO CHANGE
OVER TO SNOW FOR LOWER ELEVATIONS, WITH ACCUMULATIONS OF A FEW
INCHES POSSIBLE THROUGH WEDNESDAY. HIGHS IN THE 50S AND 60S MONDAY
WILL DROP INTO THE 40S AND 50S TUESDAY, WITH MUCH CHILLIER
WINTER-LIKE TEMPERATURES EXPECTED BY WEDNESDAY.
ELSEWHERE, AFTER A CHILLY MONDAY MORNING WITH TEMPERATURES
DROPPING NEAR FREEZING FOR THE LOWER GREAT LAKES/UPPER OHIO
VALLEY, CONDITIONS WILL REMAIN A BIT BELOW AVERAGE BROADLY ACROSS
THE NORTHEAST , WITH HIGHS MAINLY IN THE 50S TO LOW 60S.
TEMPERATURES WILL MODERATE A BIT TUESDAY WITH SOME LOW 70S
POSSIBLE.
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