259
FXUS02 KWBC 252000
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 PM EDT WED MAR 25 2026
VALID 12Z SAT MAR 28 2026 - 12Z WED APR 01 2026
..OVERVIEW
A MID-LEVEL LOW CENTERED OVER THE GULF OF ALASKA WILL FINALLY
DISLODGE FROM ITS POSITION AND DIG INTO THE WEST COAST OF THE CONUS
EARLY NEXT WEEK. THIS WILL BRING COOLER TEMPERATURES TO A REGION
THAT HAS EXPERIENCED WIDESPREAD ABOVE AVERAGE TO RECORD BREAKING
TEMPERATURES OVER THE PAST WEEK OR SO AS WELL AS INCREASINGLY
WIDESPREAD PRECIPITATION CHANCES. AS A RESULT OF THE ARRIVAL OF A
WEST COAST TROUGH, THE DOWNSTREAM RIDGE WILL SHIFT INTO THE CENTRAL
AND EASTERN U.S., SPREADING MILD TEMPERATURES INTO THOSE AREAS. A
SWATH OF SHOWERS AND THUNDERSTORMS AS WELL AS WINTRY PRECIPITATION
FURTHER NORTH IS EXPECTED EARLY TO MID-WEEK ACROSS THE
MIDWEST/GREAT LAKES INTO THE NORTHEAST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
BOTH DETERMINISTIC AND ENSEMBLE GUIDANCE IS WELL CLUSTERED WITH A
SIMILAR DEPICTION OF THE OVERALL PATTERN PARTICULARLY THROUGH THE
FIRST PART OF THE PERIOD THIS UPCOMING WEEKEND. THE UPPER-FLOW WILL
BECOME MORE QUASI-ZONAL FOLLOWING A MORE AMPLIFIED RIDGE OVER THE
WESTERN U.S. THROUGH THIS WEEK. A MORE ACTIVE PATTERN BEGINS TO SET
UP INTO EARLY NEXT WEEK AS MEAN UPPER-RIDGING BEGINS TO SHIFT FROM
OVER THE SOUTHWEST TO THE SOUTH-CENTRAL AND THEN SOUTHEAST U.S.
AND AS AN UPPER-TROUGH UPSTREAM OVER THE NORTHEASTERN PACIFIC
BEGINS TO DROP SOUTHWARD TOWARDS THE WEST COAST. THIS WILL LEAD TO
SOUTHWESTERLY FLOW ACROSS MUCH OF THE COUNTRY WITH BOTH AN ACTIVE
NORTHERN STREAM AND POTENTIAL SOUTHERN STREAM PERTURBATIONS LEADING
TO INCREASING UNCERTAINTY IN THE FORECAST DETAILS DOWNSTREAM
ACROSS THE CENTRAL TO EASTERN U.S. DETERMINISTIC GUIDANCE BEGINS TO
DIVERGE PARTICULARLY WITH THE HANDLING OF AN EXPECTED WAVY FRONTAL
BOUNDARY ACROSS THE PLAINS/MIDWEST/NORTHEAST AND THUS THE
NORTHWARD EXTENT OF AN EXPANDING WARM SECTOR INTO MID-NEXT WEEK.
SOME OF THE DETERMINISTIC GUIDANCE IS FURTHER NORTH ESPECIALLY WITH
EASTWARD EXTENT, WHILE THE GFS REMAINS FURTHER NORTH TO THE WEST
COMPARED TO ECMWF/ECMWF AIFS AND CMC. MEANWHILE, THE MEANS OFFER AN
EXPECTED MORE MUTED COMPROMISE WHICH SERVES AS A GOOD BASELINE,
AND WITH PRECIPITATION COVERAGE GENERALLY REFLECTED WELL IN THE NBM
GIVEN THE UNCERTAINTY. ADDITIONAL UNCERTAINTY IS TIED TO HOW QUICK
AND FAR THE UPPER-TROUGH WILL DIG ALONG THE WEST COAST, WITH THE
GFS CURRENTLY THE FASTEST. HOWEVER, AT LEAST THROUGH THE CURRENT
FORECAST PERIOD, THE COVERAGE AND AMOUNTS OF PRECIPITATION ACROSS
THE WESTERN U.S. IS REASONABLY WELL AGREED UPON.
THE UPDATED WPC FORECAST USED A ROUGHLY EQUAL BLEND OF THE
GFS/ECMWF/ECMWF AIFS THROUGH THE EARLY PART OF THE PERIOD WITH A
SMALL CONTRIBUTION FROM THE ECENS/GEFS MEANS WHILE GUIDANCE WAS
MORE CLOSELY CLUSTERED. THE MEANS ARE INITIALLY INCREASED TO 35%
AND THEN 55% OF THE BLEND IN THE MID- TO LATE PERIOD AS THE
DETERMINISTIC GUIDANCE BEGINS TO DIVERGE/DIFFER MORE FROM THE MORE
MUTED ENSEMBLE MEANS. THE ECMWF AIFS IS USED TO PROVIDE ADDITIONAL
DETAILS AS IT PROVIDES SOME SIMILARITY TO THE CMC WITHIN THE
ENVELOPE OF THE OTHER GUIDANCE WHILE AVOIDING PORTIONS OF THE CMC
FORECAST THAT WERE MORE OF AN OUTLIER COMPARED TO THE OTHER
GUIDANCE.
..WEATHER/HAZARDS HIGHLIGHTS
A QUASI-ZONAL MID-TO-UPPER LEVEL FLOW PATTERN WILL SETTLE IN THIS
WEEKEND INTO NEXT WEEK WITH UPPER-RIDGING SHIFTING FROM THE
SOUTHWEST TO SOUTH-CENTRAL AND THEN SOUTHEAST U.S. HIGH AND LOW
TEMPERATURES BETWEEN 20-30 DEGREES ABOVE AVERAGE MAY TIE OR BREAK
NUMEROUS RECORDS ACROSS THE AFOREMENTIONED AREAS, PARTICULARLY FROM
THE WESTERN TO CENTRAL U.S. THESE WARM TEMPERATURES ALONG WITH
GUSTY DOWNSLOPING WINDS MAY LEAD TO FIRE WEATHER CONCERNS,
ESPECAILLY ACROSS PORTIONS OF THE CENTRAL HIGH PLAINS INTO THE
PLAINS SATURDAY. TEMPERATURES WILL BEGIN TO MODERATE A BIT IN THE
WEST BENEATH THE INFLUENCE OF AN INCOMING EAST PACIFIC TROUGH. THIS
TROUGH WILL BRING MORE LOW ELEVATION RAIN AND MOUNTAINOUS SNOW TO
THE WEST COAST AND EVENTUALLY INTERMOUNTAIN WEST EARLY TO MID-NEXT
WEEK, WITH AMOUNTS AND COVERAGE TRENDING UPWARD THROUGH THE PERIOD.
MODERATE TO LOCALLY HEAVY AMOUNTS ARE BECOMING MORE LIKELY ALONG
COASTAL AREAS OF SOUTHERN OREGON INTO NORTHERN CALIFORNIA AS WELL
AS INLAND THROUGH THE SIERRA ESPECIALLY ON WEDNESDAY. SOME
ADDITIONAL SCATTERED MONSOON-LIKE SHOWERS AND THUNDERSTORMS WILL
ALSO BE POSSIBLE ACROSS PORTIONS OF THE SOUTHWEST LATE THIS WEEKEND
INTO EARLY NEXT WEEK.
EMBEDDED IMPULSES ALONG A QUASI-STATIONARY FRONTAL BOUNDARY FROM
THE PLAINS TO MIDWEST TO NORTHEAST WILL BRING INCREASING
PRECIPITATION CHANCES EARLY TO MID-NEXT WEEK. UNCERTAINTY REMAINS
AS TO THE NORTHWARD EXTENT OF THE FRONTAL BOUNDARY BUT THIS WILL
LIKELY LEAD TO ANOTHER AXIS OF MODERATE TO HEAVY RAINFALL BETWEEN
THE OHIO VALLEY AND GREAT LAKES. IN ADDITION, SOME WINTRY
PRECIPITATION IS ALSO LOOKING MORE LIKELY NORTH OF THE BOUNDARY
ACROSS THE UPPER GREAT LAKES TO INTERIOR NORTHEAST/NEW ENGLAND MID-
WEEK.
PUTNAM/KEBEDE
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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