141
FXUS02 KWBC 100646
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
246 AM EDT TUE MAR 10 2026
VALID 12Z FRI MAR 13 2026 - 12Z TUE MAR 17 2026
..RECORD WARMTH ACROSS THE SOUTHWEST LATE WEEK INTO NEXT WEEK
..HEAVY SNOW/WIND THREATS NORTHWEST/ROCKIES TO THE GREAT LAKES
..PATTERN OVERVIEW
THE UPCOMING MEDIUM RANGE PERIOD SHOULD REMAIN FAIRLY AMPLIFIED
AND ACTIVE THROUGH THE PERIOD. A DEEPENING CYCLONE OVER THE GREAT
LAKES WILL BRING SOME SNOW AND GUSTY WINDS ACROSS THE REGION ON
FRIDAY. A CLIPPER SYSTEM BEHIND THIS ONE ACROSS THE NORTHERN TIER
WILL BRING HIGH WIND THREATS ACROSS THE ROCKIES AND HIGH PLAINS
INTO THE WEEKEND, AND SPREAD MODERATE SNOWFALL FROM THE NORTHERN
PLAINS INTO THE GREAT LAKES ON THE NORTH SIDE OF AN EJECTING LOW
PRESSURE SYSTEM. THE PACIFIC NORTHWEST SHOULD BE FAIRLY ACTIVE WITH
DAILY HEAVY PRECIPITATION THREATS, WITH UPPER LEVEL RIDGING
HOLDING AND BUILDING OVER THE SOUTHWEST TO BRING RECORD BREAKING
WARMTH AND MODERATE HEATRISK TO SOME AREAS.
..GUIDANCE/PREDICTABILITY ASSESSMENT
GUIDANCE REMAINS IN GOOD AGREEMENT ON THE OVERALL LARGE SCALE
PATTERN EVOLUTION THROUGH THE PERIOD, BUT DOES SHOW SOME
CONSIDERABLE UNCERTAINTY IN THE DETAILS AND TIMING OF INDIVIDUAL
SHORTWAVES THROUGH THE NORTHERN TIER. AGREEMENT AND FORECAST
CONFIDENCE HAS INCREASED WITH AN INITIAL DEEPER LOW PRESSURE SYSTEM
OVER THE GREAT LAKES. BEHIND THIS, ANOTHER SHORTWAVE DROPS INTO
THE NORTHERN PLAINS, BUT WITH MORE UNCERTAINTY IN THE SMALLER SCALE
DETAILS AND DEPTH. THIS IMPACTS FRONTAL PLACEMENT ACROSS THE
CENTRAL U.S. TO THE MIDWEST AND EXACT PLACEMENT OF AN AXIS OF HEAVY
SNOWFALL TO THE NORTH FROM THE NORTHERN PLAINS TO THE UPPER
MIDWEST/GREAT LAKES. THIS SHORTWAVE WILL DIG SOUTHWARD IN RESPONSE
TO A BUILDING RIDGE OUT WEST, RESULTING IN A HIGHLY AMPLIFIED
PATTERN LIKELY ACROSS THE CONUS BY EARLY NEXT WEEK.
THERE WERE NOT REALLY ANY NOTABLE OUTLIERS IN TONIGHTS GUIDANCE SO
THE WPC FORECAST WAS ABLE TO RELY ON A GENERAL DETERMINISTIC MODEL
BLEND FOR THE FIRST HALF OF THE PERIOD. DID INCREASE WEIGHTING OF
THE ENSEMBLE MEANS TO 60 PERCENT OF THE BLEND BY DAY 7 JUST TO HELP
MITIGATE INDIVIDUAL MODEL VARIANCES.
..WEATHER/HAZARDS HIGHLIGHTS
AN INITIAL MAIN LOW WILL MOVE INTO THE NORTHERN PLAINS/UPPER
MIDWEST/GREAT LAKES THEN NORTHERN NEW ENGLAND BRINGING
PRECIPITATION INCLUDING A SWATH OF MODEST SNOW AS WELL AS A THREAT
FOR GUSTY WINDS INTO FRIDAY AND SATURDAY.
A COUPLE OF SHORTWAVES SHOULD KEEP THE PACIFIC NORTHWEST QUITE WET
THROUGH MUCH OF THE PERIOD. THE HEAVIEST RAINFALL SHOULD BE
ASSOCIATED WITH AN ATMOSPHERIC RIVER WHICH BEGINS AT THE END OF THE
SHORT RANGE PERIOD AND EXTENDS INTO THE WEEKEND. A MARGINAL RISK
FOR EXCESSIVE RAINFALL IS HIGHLIGHTED FOR SOUTHWEST WASHINGTON AND
NORTHWEST OREGON ON FRIDAY, WITH A BRIEF BREAK IN THE MOISTURE ON
SATURDAY. HEAVY SNOWS ARE POSSIBLE IN THE HIGHER ELEVATIONS OF THE
NORTHWEST INLAND INTO THE ROCKIES. TIGHT PRESSURE GRADIENTS WILL
ALSO SUPPORT HIGH TO DAMAGING WINDS, ESPECIALLY FOR THE NORTHWEST-
ROCKIES-HIGH PLAINS FROM LATER WEEK INTO THE WEEKEND.
ANOTHER LOW PRESSURE SYSTEM WILL EMERGE INTO THE PLAINS BY THIS
WEEKEND, WITH INCREASING CONFIDENCE IN A SWATH OF MODERATE TO HEAVY
SNOW TO THE NORTH FROM THE NORTHERN PLAINS INTO THE UPPER MIDWEST
AND GREAT LAKES. THERE IS GOOD AGREEMENT ON SNOW, BUT STILL
CONSIDERABLE UNCERTAINTY IN THE EXACT AXIS AND AMOUNTS OF SNOW.
THIS ASSOCIATED SURFACE LOW AND COLD FRONT WILL PUSH INTO THE EAST
EARLY NEXT WEEK WITH WIDESPREAD PRECIPITATION EXPECTED AHEAD OF THE
SYSTEM. SOME LAKE EFFECT SNOW IS POSSIBLE DOWNWIND OF THE GREAT
LAKES BEHIND THIS SYSTEM.
HEAT FROM THE SOUTHWEST TO THE CENTRAL GREAT BASIN WILL BUILD
THROUGH THE PERIOD, WITH WIDESPREAD RECORD BREAKING VALUES
POSSIBLE. MODERATE TO VERY LOCALIZED MAJOR HEATRISK IS FORECAST
ACROSS PARTS OF SOUTHERN CALIFORNIA FROM ROUGHLY SANTA BARBARA TO
SAN DIEGO AS TEMPERATURES APPROACH OR EXCEED 90 DEGREES IN SOME
PLACES. ABOVE NORMAL TEMPERATURES WILL OVERSPREAD THE SOUTH AS
WELL, WITH SOME RECORDS POSSIBLE INTO THE SOUTHERN PLAINS, AND
ANOTHER BRIEF WARMUP FOR THE MIDWEST AND THE EAST. THIS WILL BE
SHORT LIVED THOUGH AS THE NEXT TROUGH INTO THE NORTH- CENTRAL U.S.
EARLY NEXT WEEK WILL BRING WITH IT BELOW NORMAL TEMPERATURES WITH
DAYTIME HIGHS 10 TO 20 DEGREES BELOW NORMAL BY NEXT MONDAY AND
TUESDAY OVER THE NORTHERN/CENTRAL PLAINS INTO THE MIDWEST AND THE
EAST.
SANTORELLI
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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