028
FXUS01 KWBC 050800
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 AM EDT MON MAY 05 2025
VALID 12Z MON MAY 05 2025 - 12Z WED MAY 07 2025
...A CONTINUED OMEGA BLOCK PATTERN OVER THE LOWER 48 WILL LEAD TO
PROLONGED PERIODS OF UNSETTLED WEATHER AND COOLER TEMPERATURES TO
START THE WEEK...
...INCREASING FLASH FLOOD THREAT AS WELL AS SEVERE WEATHER
EXPECTED FOR THE SOUTHERN PLAINS/LOWER MISSISSIPPI VALLEY MONDAY
INTO TUESDAY...
...LOCALLY HEAVY RAINFALL WITH FLASH FLOODING POSSIBLE FOR THE
GREATER NYC AREA/SOUTHERN NEW ENGLAND MONDAY...
A BLOCKY PATTERN REMAINS IN PLACE OVER THE LOWER 48 TO START THE
WEEK WITH A SLOW MOVING UPPER-LOW OVER THE OHIO VALLEY, ANOTHER
SLOW MOVING UPPER-LOW OVER THE SOUTHWEST, AND AN UPPER-LEVEL RIDGE
OVER PORTIONS OF THE NORTHERN PLAINS/UPPER MIDWEST IN BETWEEN. THE
UPPER-LOW OVER THE SOUTHWEST, WHICH HAS BROUGHT UNSETTLED WEATHER
TO MUCH OF THE WEST MORE BROADLY THIS WEEKEND, WILL CONTINUE TO
BRING PRECIPITATION TO THE SOUTHWEST/FOUR CORNERS REGION, EASTERN
GREAT BASIN, AND ROCKIES TODAY. SHOWERS AND THUNDERSTORMS WITH
MODERATE TO LOCALLY HEAVY RAINFALL ARE EXPECTED, WITH THE GREATEST
CHANCE FOR HEAVY RAINFALL AND SOME ISOLATED FLASH FLOODING OVER
PORTIONS OF THE DESERT SOUTHWEST. HIGHER MOUNTAIN ELEVATIONS WILL
SEE SOME HEAVY SNOWFALL ACCUMULATIONS OF 8-12"+, ESPECIALLY FOR
REGIONAL RANGES OF SOUTHWESTERN MONTANA AND NORTHWEST WYOMING
MONDAY, AND COLORADO/NORTH-CENTRAL NEW MEXICO MONDAY INTO TUESDAY.
PRECIPITATION CHANCES WILL COME DOWN SIGNIFICANTLY FOR THE
SOUTHWEST/FOUR CORNERS, GREAT BASIN, AND NORTHERN ROCKIES TUESDAY
AS THE UPPER-LOW SHIFTS EASTWARD.
A MORE FOCUSED HEAVY RAINFALL EVENT WILL DEVELOP TO THE EAST ALONG
PORTIONS OF THE CENTRAL/SOUTHERN HIGH PLAINS, SOUTHERN PLAINS, AND
INTO THE LOWER MISSISSIPPI VALLEY OVER THE NEXT COUPLE OF DAYS. AN
INFLUX OF MOIST GULF AIR WILL FLOW NORTHWESTWARD AHEAD OF A LOW
PRESSURE/FRONTAL SYSTEM EMERGING ONTO THE PLAINS COINCIDENT WITH
THE EASTWARD PROGRESSION OF THE UPPER LOW. THE COMBINATION OF THIS
ANOMALOUSLY MOIST AIR, UPPER-LEVEL DYNAMIC SUPPORT, AND UPSLOPE
FLOW WITH INCREASING PROXIMITY TO THE ROCKIES WILL BRING
WIDESPREAD SHOWERS AND THUNDERSTORMS PRODUCING HEAVY DOWNPOURS AND
THE POTENTIAL FOR SEVERAL INCHES OF RAINFALL. THIS WILL BEGIN
ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS ON MONDAY, WITH A
SLIGHT RISK OF EXCESSIVE RAINFALL (LEVEL 2/4) IN EFFECT FOR THE
THREAT OF SCATTERED INSTANCES OF FLASH FLOODING. IN ADDITION,
COOLER TEMPERATURES ALOFT AND STRENGTHENING WINDS WITH THE
APPROACH OF THE UPPER-LOW WILL LEAD TO SUFFICIENT INSTABILITY AND
DEEP-LAYER SHEAR FOR SOME MORE INTENSE, SUPERCELL THUNDERSTORMS.
THE STORM PREDICTION CENTER HAS INCLUDED AN ENHANCED RISK (LEVEL
3/5) OVER SOUTHWEST TEXAS WITH A SLIGHT RISK (LEVEL 2/5) MORE
BROADLY OVER THE SOUTHERN HIGH PLAINS FOR THE THREAT OF SEVERAL
INSTANCES OF VERY LARGE HAIL ALONG WITH DAMAGING WINDS AND A FEW
TORNADOES. THEN, ON TUESDAY, THE THREAT WILL SHIFT NORTH AND
EASTWARD AND EXPAND IN COVERAGE ALONG THE ARCING FRONTAL SYSTEM. A
MODERATE RISK OF EXCESSIVE RAINFALL IS IN EFFECT ACROSS PORTIONS
OF THE ARKLATEX AND LOWER MISSISSIPPI VALLEY WHERE UPPER-LEVEL
SUPPORT FROM THE LOW AND CONTINUED STORM DEVELOPMENT ALONG A WARM
FRONTAL BOUNDARY EXTENDING EASTWARD THROUGH THE REGION WILL BRING
REPEATED ROUNDS OF SLOW MOVING STORMS CAPABLE OF HEAVY DOWNPOURS
LATER TUESDAY AND INTO TUESDAY NIGHT WHICH MAY LEAD TO SCATTERED
TO NUMEROUS INSTANCES OF FLASH FLOODING. A BROADER SLIGHT RISK
EXTENDS NORTHWESTWARD ACROSS THE SOUTHERN PLAINS AND INTO THE
CENTRAL HIGH PLAINS WHERE INCREASING UPSLOPE FLOW ALONG THE
ROCKIES WILL SUPPORT WIDESPREAD STORMS WITH ADDITIONAL SCATTERED
INSTANCES OF FLASH FLOODING. SEVERE STORMS WILL ALSO BE POSSIBLE
ALONG AND SOUTH OF THE WARM FRONT FROM CENTRAL TEXAS EAST THROUGH
WESTERN LOUISIANA, WITH A SLIGHT RISK OF SEVERE WEATHER IN PLACE
FOR VERY LARGE HAIL, DAMAGING WINDS, AND A FEW TORNADOES.
SHOWERS AND THUNDERSTORMS WILL ALSO CONTINUE MONDAY ACROSS MUCH OF
THE NORTHEASTERN U.S. UNDER THE EASTERN UPPER-LOW, WITH STORMS
MOST LIKELY FROM THE LOWER GREAT LAKES EAST THROUGH THE
MID-ATLANTIC AND INTO SOUTHERN NEW ENGLAND. A MORE FOCUSED
CORRIDOR OF VERY MOIST SOUTHERLY ATLANTIC FLOW ALONG A COASTAL
FRONT THROUGH THE GREATER NEW YORK CITY AREA AND INTO SOUTHERN NEW
ENGLAND MAY LEAD TO SOME LOCALLY HEAVIER DOWNPOURS AND SCATTERED
FLASH FLOODING, WITH A SLIGHT RISK OF EXCESSIVE RAINFALL IN
EFFECT. STORM CHANCES WILL LINGER INTO THE DAY TUESDAY, THOUGH
WILL BECOME INCREASINGLY MORE SCATTERED WITH LESS RAINFALL
EXPECTED, BEFORE STORMS BEGIN TO COME TO AN END LATE TUESDAY NIGHT
AND INTO WEDNESDAY MORNING. ELSEWHERE, SOME SCATTERED
THUNDERSTORMS ARE FORECAST OVER THE FLORIDA PENINSULA AHEAD OF A
COLD FRONT MONDAY. THE REST OF THE COUNTRY OUTSIDE OF THE
INFLUENCE OF THE UPPER-LOWS WILL SEE DRY CONDITIONS THE NEXT
COUPLE OF DAYS.
THE OMEGA BLOCK PATTERN WILL CONTINUE TO LEAD TO FOCUSED AREAS OF
BOTH WELL BELOW NORMAL AND WELL ABOVE NORMAL TEMPERATURES TO START
THE WORK WEEK. WELL BELOW AVERAGE HIGHS ARE FORECAST FOR MUCH OF
THE OHIO AND TENNESSEE VALLEYS UNDER THE INFLUENCE OF THE EASTERN
UPPER-LOW, WITH 50S AND 60S EXPECTED. CONDITIONS SHOULD MODERATE
AND WARM A FEW DEGREES ON TUESDAY. HIGHS WILL BE CLOSER TO AVERAGE
ALONG THE EAST COAST AHEAD OF THE UPPER LOW, WITH 50S AND 60S IN
NEW ENGLAND, 60S AND 70S IN THE MID-ATLANTIC, AND 70S AND 80S FROM
THE CAROLINAS SOUTH INTO FLORIDA. CONDITIONS WILL ALSO BE WELL
BELOW AVERAGE ACROSS MUCH OF THE INTERIOR WEST AND INTO THE
CENTRAL/SOUTHERN PLAINS UNDER THE INFLUENCE OF THE WESTERN
UPPER-LOW. FORECAST HIGHS MONDAY AND TUESDAY RANGE FROM THE 50S
AND 60S FOR THE ROCKIES/GREAT BASIN AND MUCH OF THE
CENTRAL/SOUTHERN PLAINS TO THE 60S AND 70S FOR THE DESERT
SOUTHWEST AND MORE SOUTHERN AREAS OF TEXAS. IN CONTRAST, WELL
ABOVE AVERAGE CONDITIONS CONTINUE UNDER THE UPPER-RIDGE OVER THE
NORTHERN PLAINS/UPPER MIDWEST, WITH HIGHS INTO THE 70S AND 80S.
THE WEST COAST WILL ALSO SEE INCREASINGLY ABOVE AVERAGE CONDITIONS
AS AN UPPER-RIDGE BUILDS IN THE WAKE OF THE UPPER-LOW, WITH HIGHS
IN THE MID-60S TO MID-80S.
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