433
FXUS02 KWBC 151848
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
248 PM EDT WED APR 15 2026
VALID 12Z SAT APR 18 2026 - 12Z WED APR 22 2026
..GENERAL OVERVIEW
A PATTERN CHANGE IS EXPECTED ACROSS THE EASTERN HALF OF THE
COUNTRY AS A STRONG COLD FRONT HERALDS THE END OF THE EARLY SEASON
HEAT WAVE. HOT TEMPERATURES ACROSS THE EAST COAST ON SATURDAY WILL
BE REPLACED BY MORE SEASONAL READINGS BY THE START OF NEXT WEEK AS
A CANADIAN SURFACE HIGH BUILDS INTO THE REGION. OUT WEST, A NEW
STORM SYSTEM ARRIVES BY SUNDAY AND BRINGS ADDITIONAL RAIN AND
MOUNTAIN SNOW TO THE WEST COAST STATES. A BROAD UPPER RIDGE BUILDS
BETWEEN THE EASTERN U.S. TROUGH AND THE WEST COAST SYSTEM, BUT NOT
TO THE SAME MAGNITUDE AS WHAT IS CURRENTLY IN PLACE ACROSS THE
COUNTRY.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST DETERMINISTIC AND ENSEMBLE GUIDANCE CONTINUES TO SHOW
GOOD SYNOPTIC AGREEMENT ON THE PATTERN EVOLUTION DURING THE DAY 4-7
PERIOD, BUT PLENTY OF UNCERTAINTY IN THE DETAILS. THERE WAS GOOD
ENOUGH CONSENSUS ON THE TIMING OF THE INITIAL COLD FRONT INTO THE
EAST FOR AN EQUAL BLEND OF THE DETERMINISTIC GUIDANCE FOR SATURDAY
AND SUNDAY. AFTER THIS, THE FOCUS SHIFTS OUT WEST TO AN UPPER LOW
MOVING TOWARDS CALIFORNIA. THE 00Z ECMWF/ECENS WERE NOTABLY FASTER
THAN THE CONSENSUS, BUT SOME OF THE NEW 12Z GUIDANCE DID SPEED UP
(WHILE THE ECMWF) DID SLOW DOWN. GIVEN THE VARIABILITY, PREFER TO
STICK CLOSER TO THE GEFS MEAN AND WPC CONTINUITY, SO THE LATTER
HALF OF THE PERIOD WAS WEIGHTED MORE HEAVILY TOWARDS THOSE
SOLUTIONS. 13Z NBM WAS A REASONABLE STARTING POINT FOR MUCH OF THE
FORECAST BUT DID DECREASE QPF COVERAGE A BIT FOR THE WEST SINCE IT
WAS TOO HEAVILY INFLUENCED BY THE FASTER 00Z ECMWF.
..WEATHER/HAZARDS HIGHLIGHTS
A STRONG COLD FRONT CROSSING THE OHIO VALLEY, MID-SOUTH, AND INTO
TEXAS ON SATURDAY IS EXPECTED TO BE ACCOMPANIED BY A CORRIDOR OF
SHOWERS AND THUNDERSTORMS. GREATER COVERAGE OF CONVECTION IS LIKELY
FROM EASTERN TEXAS TO CENTRAL MISSISSIPPI WHERE BETTER MOISTURE
CONVERGENCE AND INSTABILITY WILL EXIST, AND A MARGINAL RISK OF
EXCESSIVE RAINFALL WILL REMAIN VALID HERE FOR THE DAY 4/SATURDAY
OUTLOOK. THERE WILL LIKELY BE A SECOND MAXIMA OF HEAVIER RAINFALL
FROM OHIO INTO PENNSYLVANIA, AND THIS AREA MAY EVENTUALLY NEED A
MARGINAL RISK AREA IN LATER OUTLOOKS IF AMOUNTS TREND UPWARD, BUT
THE FRONT SHOULD BE MORE PROGRESSIVE IN THIS AREA AS WELL. THE
STORM PREDICTION CENTER IS ALSO MONITORING THE NORTHERN OHIO VALLEY
FOR THE POTENTIAL OF SEVERE WEATHER ON SATURDAY AHEAD OF THE
FRONT.
GOING INTO DAY 5/SUNDAY, MODERATE TO LOCALLY HEAVY RAINFALL IS
EXPECTED FOR THE NORTHEAST U.S. BUT APPEARS TO BE PROGRESSIVE
ENOUGH TO LIMIT THE FLOOD POTENTIAL. HOWEVER, A POTENTIAL
ATMOSPHERIC RIVER WITH THE NEXT PACIFIC STORM SYSTEM MAY PRODUCE
ENOUGH RAINFALL ACROSS NORTHERN CALIFORNIA TO LEAD TO SOME 1-2 INCH
RAINFALL ON SUNDAY, AND THEREFORE A MARGINAL RISK AREA IS IN PLACE
HERE. MOUNTAIN SNOW WILL ALSO BE COMMONPLACE FOR THE HIGHER
TERRAIN OF THE SIERRA AND THE CASCADES, AND LIGHTER SNOWS FOR THE
NORTHERN ROCKIES.
THE RECORD BREAKING EARLY SEASON HEAT WAVE FOR MANY AREAS OF THE
EASTERN U.S. WILL COME TO AN END BY SUNDAY AS THE HUGE UPPER RIDGE
GETS SUPPRESSED, AND A COLD FRONT BRINGS A RETURN TO CONDITIONS
MORE TYPICAL OF SPRING TO BEGIN NEXT WEEK. THE SUMMER- LIKE HEAT
WILL PERSIST ON SATURDAY FROM THE MID-ATLANTIC TO FLORIDA WITH
HIGHS IN THE UPPER 80S TO MIDDLE 90S, AND THEN BY SUNDAY THE
ANOMALOUS WARMTH IS CONFINED MAINLY TO THE EASTERN CAROLINAS AND
SOUTHWARD BEFORE THE ENTIRE EAST COAST GETS RELIEF ON MONDAY.
CONDITIONS WILL TURN RATHER CHILLY FROM MICHIGAN TO NEW ENGLAND
WITH HIGHS MAINLY IN THE 40S TO LOWER 50S, AND FROST/FREEZE
CONDITIONS AT NIGHT. WARMTH RETURNS TO THE PLAINS AS HIGHS REACH
INTO THE 80S FROM WESTERN TEXAS TO NEBRASKA BY TUESDAY.
SANTORELLI/HAMRICK
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 (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
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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