335
FXUS02 KWBC 220642
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
142 AM EST SAT FEB 22 2025
VALID 12Z TUE FEB 25 2025 - 12Z SAT MAR 01 2025
..OVERVIEW
THE UPPER FLOW PATTERN SHOULD REMAIN RATHER PROGRESSIVE THROUGH
MUCH OF THE MEDIUM RANGE PERIOD. BY TUESDAY, A NORTHERN STREAM
SHORTWAVE WILL BE SHIFTING THROUGH THE NORTHEAST, WITH A SOUTHERN
STREAM WAVE THROUGH THE GULF AND FLORIDA. OUT WEST, A SHORTWAVE
INTO THE PACIFIC NORTHWEST ON TUESDAY WILL PROGRESS DOWNSTREAM,
WITH EVENTUAL DEEPENING OVER THE EAST BY THURSDAY OR FRIDAY. THIS
ALLOWS FOR AN AMPLIFYING RIDGE UPSTREAM ACROSS THE WEST LATE WEEK,
WITH A SOUTHERN STREAM TROUGH OR CUTOFF LOW MOVING INLAND ACROSS
SOUTHERN CALIFORNIA AROUND NEXT SATURDAY.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE SHOWS REASONABLE AGREEMENT IN THE OVERALL PATTERN
EVOLUTION DESCRIBED ABOVE, THOUGH WITH TYPICAL DETAIL DIFFERENCES
THAT COULD HAVE SENSIBLE WEATHER IMPACTS AT TIMES. THE FIRST FEW
DAYS OF THE PERIOD, MODELS WERE CLUSTERED WELL ENOUGH FOR A MULTI-
MODEL BLEND BETWEEN THE GFS, ECMWF, AND CMC AS A STARTING POINT FOR
THE WPC PROGS. BY WEDNESDAY AND BEYOND, DIFFERENCES IN ENERGY
THROUGH THE MEAN MIDWEST-EAST TROUGH BECOME MORE APPARENT, AND
ESPECIALLY AS THE OVERALL TROUGH DEEPENS LATER IN THE WEEK. THE 12Z
CMC WAS MUCH STRONGER WITH THIS BY NEXT FRIDAY, INDICATING A
CLOSED LOW OVER THE SOUTHEAST, AND A NOTABLE SURFACE LOW PRESSURE
SYSTEM OFF THE MID- ATLANTIC COAST. THE GFS AND ECMWF WERE MORE
ELONGATED WITH THE TROUGH, WITH LESS STREAM SEPARATION. THE NEW 00Z
CMC RUN TONIGHT DID COME IN LOOKING MORE LIKE THE GFS AND ECMWF.
THERE ALSO REMAINS CONSIDERABLE TIMING UNCERTAINTY WITH A CUTOFF
LOW INTO CALIFORNIA FRIDAY OR SATURDAY, THOUGH THERE IS GENERAL
AGREEMENT ON THE PRESENCE OF THIS FEATURE. LOTS OF RUN TO RUN
VARIABILITY IN TIMING AND SO LEANING TOWARDS THE ENSEMBLE MEANS,
WHICH WERE ON THE FASTER SIDE OF THE ENVELOPE, DUE TO A WEAKER
SYSTEM, SEEMED LIKE THE BEST OPTION AT THIS POINT.
..WEATHER/HAZARDS HIGHLIGHTS
AN ATMOSPHERIC RIVER INTO THE PACIFIC NORTHWEST DURING THE SHORT
RANGE PERIOD SHOULD BE INLAND BY THE START OF THE MEDIUM RANGE
PERIOD, WITH ONLY LIGHTER LINGERING RAINS EXPECTED. SOME ENHANCED
SNOWS WILL REACH THE NORTHERN INTERMOUNTAIN WEST/ROCKIES AS THE
SYSTEM TRANSLATES INLAND ON TUESDAY, BUT THE NORTHWEST WILL TREND
DRIER MIDWEEK AND BEYOND AS UPPER RIDGING BUILDS IN. GUSTY WINDS
ARE ALSO POSSIBLE ACROSS PARTS OF THE NORTHWESTERN TO NORTH-
CENTRAL U.S. NEXT WEEK. THE MOST PERSISTENT HIGHEST WINDS ARE
LIKELY TO BE ALONG THE NORTHERN/CENTRAL ROCKIES RIDGES, WHILE
SPILLING INTO THE DAKOTAS AT TIMES.
DOWNSTREAM, NORTHERN STREAM ENERGY WILL SPREAD LIGHT PRECIPITATION
FROM THE GREAT LAKES REGION THROUGH NEW ENGLAND INTO TUESDAY. THEN
MODERATE CYCLOGENESIS AND FRONTOGENESIS ARE LIKELY OVER THE
NORTHERN PLAINS/MISSISSIPPI VALLEY WEDNESDAY AND WORK INTO THE EAST
BY THURSDAY AND FRIDAY. THIS COULD LEAD TO ANOTHER ROUND OF RAIN
AND NORTHERN TIER SNOW MAKING ITS WAY FROM THE NORTH- CENTRAL TO
EAST- CENTRAL U.S. MIDWEEK AND ACROSS THE EAST BY THURSDAY.
BY NEXT WEEK, MUCH OF THE CONUS WILL BE MUCH ABOVE NORMAL IN TERMS
OF TEMPERATURES WITH DECENT COVERAGE OF PLUS 10-25 DEGREE
ANOMALIES. BEST POTENTIAL FOR HIGHEST ANOMALIES WILL BE NEAR THE
NORTHERN PLAINS. WITH A BUILDING RIDGE OUT WEST, THIS SHOULD HOLD
INTO NEXT WEEKEND, BUT THE EAST SHOULD MODERATE BACK TO NORMAL (OR
SLIGHTLY BELOW IN SPOTS) BY LATE WEEK UNDERNEATH OF TROUGHING.
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page