662
FXUS02 KWBC 241934
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
334 PM EDT FRI APR 24 2026
VALID 12Z MON APR 27 2026 - 12Z FRI MAY 01 2026
...A DEEPENING LOW PRESSURE SYSTEM WILL PRODUCE HEAVY RAIN AND
SEVERE WEATHER ACROSS THE EAST-CENTRAL U.S. MONDAY/TUESDAY...
..OVERVIEW
IT IS STILL THE CASE THAT AN ACTIVE PATTERN CONTINUES ACROSS THE
CONUS NEXT WEEK, BEGINNING WITH A STRENGTHENING LOW PRESSURE SYSTEM
THAT IS SET TO BRING HEAVY RAIN AND SEVERE WEATHER ACROSS PORTIONS
OF THE MISSISSIPPI VALLEY ON MONDAY. AS THE MAIN LOW PUSHES ACROSS
THE GREAT LAKES INTO SOUTHERN CANADA, THE TRAILING COLD FRONT WILL
PRESS ACROSS THE EAST TUESDAY INTO WEDNESDAY AND BRING VARYING
RAIN CHANCES THERE. THE SOUTHERN PORTION OF THE FRONT WILL SAG INTO
THE SOUTHEASTERN U.S. BEFORE STALLING OUT, SUPPORTING NUMEROUS
SHOWERS AND STORMS AND POTENTIALLY ANOTHER HEAVY RAIN RISK.
MEANWHILE, A PACIFIC SYSTEM WILL LIKELY SLIDE ACROSS SOUTHERN
CALIFORNIA AND THE SOUTHWEST MID TO LATE WEEK, BRINGING CHANCES FOR
LOW ELEVATION RAIN AND MOUNTAIN SNOW ACROSS THE WINDY
INTERMOUNTAIN WEST, ROCKIES AND PLAINS. THERE IS A GROWING GUIDANCE
SIGNAL THAT THIS MAY THEN LEAD TO A DOWNSTREAM HEAVY RAIN/RUNOFF
AND STRONG CONVECTIVE DEVELOPMENT AND EXPANSION THREAT BROADLY OVER
THE SOUTH-CENTRAL U.S. TO MONITOR FOR NEXT THURSDAY/FRIDAY.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST GUIDANCE HAS A FAIRLY DECENT HANDLE ON THE LARGE SCALE
PATTERN THROUGH MOST OF THE MEDIUM RANGE PERIOD, FEATURING BROAD
TROUGHING FROM THE CENTRAL TO EASTERN U.S., RIDGING OVER THE
PACIFIC NORTHWEST, AND AN UPPER LOW MOVING ACROSS THE SOUTHWEST
U.S. WITH THAT BEING SAID, THE SMALLER SCALE DETAILS REMAIN MORE
UNCERTAIN. THIS HAS PARTICULARLY BEEN THE CASE RECENTLY WITH THE
FORECAST TRACK AND EVOLUTION OF A PACIFIC TO SOUTHWEST U.S. UPPER
LOW, AS THE TIMING AND AMPLITUDE OF DOWNSTREAM SHORTWAVES ON THE
BACKSIDE OF BROAD UPPER TROUGHING LEAD TO SIGNIFICANT RUN-TO-RUN
DIFFERENCES OF THE UPPER LOW'S FORWARD SPEED, POSITIONING, AND
SENSIBLE WEATHER. THE WPC PRODUCT SUITE WAS DERIVED WITH FAVOR
TOWARD A SLOWER THAN CONCENSUS PROGRESSION OF THIS SYSTEM INTO
LATER NEXT WEEK GIVEN STREAM SEPARATION AND CLOSED NATURE. THE GOOD
NEWS IS THAT NEW 12 UTC GUIDANCE HAS STRONGLY TRENDED IN THIS
SLOWER DIRECTION, BOLSTERING FORECAST CONFIDENCE. THE 12 CANADIAN
IS NOW IN PARTICULAR MUCH LESS PROGRESSIVE WITH THIS SYSTEM,
TRENDING TOWARD OUR FAVORED BLEND OF THE GFS/ECMWF AND GEFS/ECMWF
ENSEMBLE MEANS AND MORE IN LINE WITH THE NATIONAL BLEND OF MODELS.
..WEATHER/HAZARDS HIGHLIGHTS
A POTENT NEGATIVELY-TILTED SHORTWAVE EJECTING OUT OF THE CENTRAL
ROCKIES AND ACROSS THE CENTRAL PLAINS AND UPPER MIDWEST WILL
SUPPORT THE RAPID STRENGTHENING OF A SURFACE LOW PRESSURE SYSTEM
ON MONDAY. FLOW AROUND THE LOW WILL DRAW ANOMALOUS MOISTURE AND
INSTABILITY NORTHWARD FROM THE GULF, SETTING THE STAGE FOR NUMEROUS
SHOWERS AND THUNDERSTORMS ACROSS THE MISSISSIPPI VALLEY MONDAY
AFTERNOON AND EVENING WITH THE POTENTIAL FOR HEAVY RAIN AND SEVERE
WEATHER. THE STORM PREDICTION CENTER HAS HIGHLIGHTED THE MID-
MISSISSIPPI VALLEY AS HAVING THE GREATEST THREAT FROM THUNDERSTORMS
THAT COULD PRODUCE DAMAGING WINDS, LARGE HAIL, AND EVEN A FEW
TORNADOES. HEAVY RAIN THAT CAN LEAD TO FLASH FLOODING WILL ALSO BE
A CONCERN, ESPECIALLY AS CLUSTERS OF THUNDERSTORMS WITH HIGH
RAINFALL RATES MERGE AND REPEATEDLY TRAIN OVER THE SAME AREAS. A
MARGINAL RISK REMAINS IN PLACE FROM THE UPPER MIDWEST TO THE LOWER
MISSISSIPPI VALLEY FOR THE DAY 4/MONDAY ERO.
AS THE STRONG SURFACE LOW LIFTS ACROSS THE GREAT LAKES AND TRACKS
INTO SOUTHERN CANADA, THE COLD FRONT TRAILING IN THE WAKE OF THE
LOW WILL SLIDE TO THE SOUTH AND EAST TUESDAY INTO WEDNESDAY,
SPREADING SHOWERS AND THUNDERSTORMS INTO THE EASTERN U.S. THE FRONT
WILL BEGIN TO LOSE STEAM AND STALL OUT OVER THE SOUTH-CENTRAL TO
SOUTHEASTERN U.S. INTO TUESDAY, BECOMING THE FOCUS FOR ANOTHER
ROUND OF HEAVY RAIN AND POSSIBLE SEVERE WEATHER. SIGNIFICANT
MOISTURE AND INSTABILITY POOLING ALONG THE STALLING BOUNDARY COULD
LEAD TO CLUSTERS OF STORMS WITH HIGH RAINFALL RATES, SUPPORTING THE
POTENTIAL FOR ISOLATED INSTANCES OF FLASH FLOODING. AS A RESULT, A
MARGINAL RISK ERO WAS INTRODUCED FROM THE ARKLATEX REGION EASTWARD
TO THE MID-SOUTH AND TENNESSEE VALLEY FOR DAY 5/TUESDAY.
BY MID TO LATE WEEK, A PACIFIC SYSTEM WILL LIKELY PUSH INLAND
ACROSS SOUTHERN CALIFORNIA, THE SOUTHWEST, AND THE FOUR CORNERS
STATES, SPREADING LIGHT TO MODERATE LOW ELEVATION RAIN AND HIGHER
ELEVATION MOUNTAIN SNOW INTO THE REGION. THERE IS A GROWING SIGNAL
FOR SIGNIFICANT RAINFALL WILL DEVELOP AND EXPAND/INTENSIFY WITH
SYSTEM APPROACH AND LEAD RETURN GULF INFLOW OVER THE SOUTH-CENTRAL
U.S. FOR THURSDAY/FRIDAY TO MONITOR.
WARMER THAN AVERAGE TEMPERATURES ARE LIKELY TO CONTINUE ACROSS THE
SOUTHERN PLAINS THROUGH MIDWEEK, AND AHEAD OF THE COLD FRONT INTO
THE MISSISSIPPI AND OHIO VALLEYS THROUGH EARLY NEXT WEEK.
TEMPERATURES IN THE 90S WILL BE COMMON ACROSS TEXAS. MEANWHILE,
BELOW AVERAGE TEMPERATURES WILL CONTINUE FOR MUCH OF THE WEST AND
NORTHERN/CENTRAL PLAINS UNDER THE BROAD TROUGHING THROUGH MONDAY
BEFORE SHIFTING INTO THE NORTH-CENTRAL U.S. THROUGH MIDWEEK. COOLER
THAN NORMAL TEMPERATURES IN THE WAKE OF THE COLD FRONT WILL THEN
CONTINUE TO EXPAND TO THE SOUTH AND EAST THURSDAY INTO FRIDAY,
WHILE THE PACIFIC NORTHWEST WARMS BACK CLOSER TO OR SLIGHTLY ABOVE
NORMAL.
MILLER/SCHICHTEL
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC MEDIUM RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS, QUANTITATIVE PRECIPITATION FORECAST, EXCESSIVE RAINFALL OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY MESSAGES ARE AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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