009
FXUS02 KWBC 240652
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
152 AM EST MON FEB 24 2025
VALID 12Z THU FEB 27 2025 - 12Z MON MAR 03 2025
..OVERVIEW
THE UPPER FLOW PATTERN SHOULD REMAIN RATHER PROGRESSIVE THROUGH
MUCH OF THE UPCOMING MEDIUM RANGE PERIOD. A DEEPENING SURFACE
TROUGH INTO THE EAST ON THURSDAY AND FRIDAY, WILL EVENTUALLY BE
REINFORCED BY SECONDARY ENERGY NEXT WEEKEND. MEANWHILE, A RIDGE
AXIS OVER THE WEST WILL BE UNDERCUT BY A SOUTHERN STREAM CUTOFF LOW
MOVING INLAND ACROSS SOUTHERN CALIFORNIA AND INTO THE SOUTHWEST
AND SOUTHERN U.S. THIS WEEKEND AND EARLY NEXT WEEK. ANOTHER DEEP
AND ELONGATED UPPER TROUGH LOOKS TO MOVE INTO THE WEST COAST NEXT
SUNDAY OR MONDAY, AS UPPER RIDGING BEGINS TO FILL IN AGAIN OVER THE
EAST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THERE CONTINUES TO BE REASONABLE AGREEMENT ON THE LARGE SCALE
PATTERN DURING THE MEDIUM RANGE PERIOD, BUT STILL PLENTY OF
UNCERTAINTY IN THE DETAILS, SOME OF WHICH COULD HAVE NOTABLE
SENSIBLE WEATHER IMPACTS. THERE ARE STILL SOME LINGERING TIMING
UNCERTAINTIES ON THE TROUGH ACROSS THE EAST LATE THIS WEEK, BUT A
GENERAL MODEL COMPROMISE BETWEEN THE GFS, ECMWF, AND CMC GUIDANCE
SEEMED LIKE A GOOD STARTING POINT. OUT WEST, GUIDANCE HAS TRENDED
MORE CONSISTENT WITH THE TIMING OF A CUTOFF UPPER LOW INTO
CALIFORNIA ON SATURDAY, BUT SOME DISAGREEMENT DOWNSTREAM ON HOW
QUICKLY IT WEAKENS AND GETS ABSORBED INTO THE LARGE SCALE FLOW OVER
THE SOUTHERN PLAINS. THE MOST UNCERTAIN PART OF THE MEDIUM RANGE
PERIOD IS WITH THE SECOND ELONGATED TROUGH/UPPER LOW INTO THE WEST
COAST AROUND MONDAY OF NEXT WEEK. THROUGH THE 12Z/18Z FEB 23 MODEL
RUNS, THE ECMWF AND ITS ENSEMBLE MEAN WERE CONSIDERABLY FASTER THAN
CONSENSUS, WITH SEVERAL OF THE EC-BASED AI MODELS ALSO SUPPORTING
A SLOWER PROGRESSION OF THE LOW. THE LATE PERIOD WPC FORECAST
LEANED CLOSER TO THE SLOWER CMC AND GFS ALONG WITH THE ENSEMBLE
MEANS, ANCHORED BY THE NAEFS.
..WEATHER/HAZARDS HIGHLIGHTS
A COLD FRONT INTO THE EAST WILL SPREAD GENERALLY LIGHT TO MODERATE
PRECIPITATION INTO THURSDAY. SOME PRECIPITATION COULD BE SNOW IN
THE NORTHERN PART OF THE PRECIPITATION SHIELD ACROSS THE INTERIOR
NORTHEAST. A CLIPPER SYSTEM SHOULD BRING AN ADDITIONAL ROUND OF
PRECIPITATION TO THE GREAT LAKES AND NORTHEAST FRIDAY INTO
SATURDAY.
A BUILDING RIDGE SHOULD KEEP CONDITIONS QUIET AND DRY ACROSS THE
WEST THURSDAY AND FRIDAY, OTHER THAN A LITTLE LIGHT PRECIPITATION
POSSIBLE IN THE PACIFIC NORTHWEST. THE SOUTHERN STREAM UPPER LOW
MOVING ACROSS SOUTHERN CALIFORNIA FRIDAY AND INLAND NEXT WEEKEND
MAY LEAD TO LIGHT SHOWERS OVER CALIFORNIA, THE SOUTHWEST, AND INTO
THE SOUTH- CENTRAL U.S., WITH INCREASING RAIN CHANCES IN THE
SOUTHERN PLAINS BY NEXT SUNDAY AS MOISTURE INCREASES. THE NORTHERN
STREAM TROUGH MOVING THROUGH THE EASTERN PACIFIC AND INTO THE WEST
NEXT WEEKEND WILL ALSO BRING PRECIPITATION BACK INTO THE FORECAST
FOR THE WEST COAST AND GREAT BASIN.
MUCH ABOVE NORMAL TEMPERATURES WILL BE WELL ESTABLISHED BY
THURSDAY ACROSS THE WEST AND INTO THE NORTHERN/CENTRAL PLAINS. THE
GREATEST ANOMALIES WILL BE ACROSS THE PLAINS WITH DAYTIME HIGHS 20
TO LOCALLY 30 DEGREES ABOVE NORMAL, WITH 60S FOR HIGHS AS FAR NORTH
AS NEBRASKA OR PERHAPS EVEN SOUTH DAKOTA AT TIMES. THE ABOVE
NORMAL TEMPERATURES WILL SPREAD SOUTH AND EAST, WITH THE WEST COAST
TRENDING COOLER BY EARLY NEXT WEEK. ACROSS THE EAST, TEMPERATURES
MAY INITIALLY BE WARM ON THURSDAY, BUT SHOULD TREND BACK TOWARDS
NORMAL (OR BELOW NORMAL) BY THE WEEKEND.
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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