088
FXUS02 KWNH 090712
PREEPD
PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
311 AM EDT MON MAR 9 2026
VALID 12Z THU MAR 12 2026 - 12Z MON MAR 16 2026
...RECORD WARM TEMPERATURES FORECAST ACROSS THE SOUTHWEST LATE
WEEK INTO NEXT WEEKEND...
..PATTERN OVERVIEW
THE MEDIUM RANGE PERIOD BEGINS THURSDAY WITH A FAIRLY PROGRESSIVE
BUT AMPLIFIED PATTERN ACROSS THE CONUS WHICH MAY GRADUALLY TREND
SOMEWHAT LESS AMPLIFIED WITH TIME. ON THURSDAY, TROUGHING OVER THE
GREAT LAKES AND NORTHEAST WILL DRIVE A STRONG COLD FRONT THROUGH
THE EASTERN U.S. WITH AN ONGOING ATMOSPHERIC RIVER BRINGING HEAVY
PRECIPITATION THREATS TO THE PACIFIC NORTHWEST. A CLIPPER SYSTEM
ACROSS THE NORTHERN TIER WILL BRING HIGH WIND THREATS ACROSS THE
ROCKIES INTO THE HIGH PLAINS INTO THE WEEKEND, WITH GUSTY WINDS TO
ACCOMPANY A DEEPENING CYCLONE OVER THE GREAT LAKES AND MIDWEST LATE
IN THE WEEK AS WELL. MEANWHILE, UPPER LEVEL RIDGING WILL BUILD AND
HOLD OVER THE SOUTHWEST U.S. BRINGING WELL ABOVE TO RECORD
BREAKING WARMTH ACROSS THE REGION WITH SOME MODERATE HEATRISK NOTED
FOR SOUTHERN CALIFORNIA.
..GUIDANCE/PREDICTABILITY ASSESSMENT
GUIDANCE REMAINS WELL CLUSTERED ON THE LARGE SCALE WITH THE
PATTERN EVOLUTION THROUGH THE PERIOD. THERE REMAINS SOME
UNCERTAINTY IN THE DETAILS OF INDIVIDUAL SHORTWAVES THROUGH THE
NORTHERN TIER WHICH IMPACT SENSIBLE WEATHER GRIDS AND EXACT
PLACEMENT OF A DEEPENING LOW PRESSURE SYSTEM. CMC WAS A BIT SHARPER
WITH THE SHORTWAVE THROUGH THE GREAT LAKES AND NORTHEAST LATE THIS
WEEK AND WAS NOT INCLUDED IN THE WPC FORECAST BLEND. MODELS SHOW
GOOD AGREEMENT THAT PATTERN MAY RETURN TO AMPLIFIED BY EARLY NEXT
WEEK BUT WITH SOME TIMING AND STRENGTH QUESTIONS WITH MEAN
TROUGHING ACROSS THE CENTRAL U.S. WHICH WOULD IMPACT THE STRENGTH
OF THE SOUTHWEST RIDGE AS WELL. THE WPC FORECAST TONIGHT USED A
NON-CMC DETERMINISTIC MODEL BLEND FOR THE FIRST HALF OF THE PERIOD,
TRANSITIONING TO A MORE HEAVILY WEIGHTED BLEND OF THE ENSEMBLE
MEANS FOR THE LATTER HALF TO HELP MITIGATE INDIVIDUAL MODEL
VARIANCES.
..WEATHER/HAZARDS HIGHLIGHTS
A STRONG COLD FRONT INTO THE EAST ON THURSDAY WILL BRING
WIDESPREAD, MODERATE TO LOCALLY HEAVY, RAINFALL TO THE REGION. THIS
FRONT SHOULD BE PROGRESSIVE ENOUGH TO LIMIT THE OVERALL FLOOD
THREAT THOUGH. SOME SNOW OR WINTRY MIX IS POSSIBLE ON THE NORTHERN
EDGE OF THE PRECIPITATION SHIELD ACROSS THE INTERIOR NORTHEAST AND
POSSIBLY INTO PARTS OF THE NORTHERN MID-ATLANTIC. MODEST LAKE
EFFECT SNOWFALL IS ALSO POSSIBLE DOWNWIND OF THE ESPECIALLY THE
LOWER GREAT LAKES. THE NEXT LOW INTO THE UPPER MIDWEST/GREAT LAKES
WILL BRING RENEWED PRECIPITATION CHANCES AS WELL AS A THREAT FOR
GUSTY WINDS FRIDAY AND SATURDAY.
A COUPLE OF SHORTWAVES SHOULD KEEP THE PACIFIC NORTHWEST 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 THROUGH AT LEAST FRIDAY. MARGINAL
RISKS FOR EXCESSIVE RAINFALL ARE HIGHLIGHTED FOR SOUTHWEST
WASHINGTON AND NORTHWEST OREGON BOTH THURSDAY AND FRIDAY. HEAVY
SNOWS ARE POSSIBLE IN THE HIGHER ELEVATIONS OF THE NORTHWEST AND
INTO THE ROCKIES. TIGHT PRESSURE GRADIENTS WILL ALSO SUPPORT HIGH
TO DAMAGING WINDS, ESPECIALLY FOR THE NORTHWEST-ROCKIES-HIGH PLAINS
DURING THE LATTER HALF OF NEXT WEEK AND POSSIBLY INTO THE WEEKEND.
FOLLOWING A VERY WARM START TO THE WEEK, THE COLD FRONT THROUGH
THE EAST SHOULD BRING TEMPERATURES BACK TOWARDS NORMAL FOR THE EAST
BY THURSDAY AND FRIDAY. HEAT ACROSS THE SOUTHWEST WILL BUILD, WITH
RECORD BREAKING VALUES POSSIBLE, ESPECIALLY THURSDAY AND FRIDAY.
MODERATE TO VERY LOCALIZED MAJOR HEATRISK IS FORECAST ACROSS PARTS
OF SOUTHERN CALIFORNIA FROM ROUGHLY SANTA BARBARA TO SAN DIEGO AS
TEMPERATURES SOAR INTO THE 80S, WITH 90S FARTHER INLAND. ABOVE
NORMAL TEMPERATURES WILL OVERSPREAD THE SOUTH AS WELL, WITH SOME
RECORDS POSSIBLE INTO THE SOUTHERN PLAINS. 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 ACROSS THE NORTHERN/CENTRAL PLAINS AND INTO THE
MIDWEST.
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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