986
FXUS02 KWBC 210700
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
159 AM EST WED FEB 21 2024
VALID 12Z SAT FEB 24 2024 - 12Z WED FEB 28 2024
..OVERVIEW
AN UPPER RIDGE TRAVERSING THE COUNTRY THIS WEEKEND INTO EARLY NEXT
WEEK WILL SPREAD MUCH ABOVE NORMAL TEMPERATURES TO THE PLAINS AND
MIDWEST AND EVENTUALLY THE EAST BY THE MIDDLE OF NEXT WEEK.
MEANWHILE AN EASTERN PACIFIC UPPER LOW SHOULD SPREAD SOME
INCREASING PRECIPITATION CHANCES TO THE WEST COAST ONCE AGAIN,
POSSIBLY BY THE WEEKEND BUT MORE CONFIDENTLY BY EARLY NEXT WEEK AS
NORTHERN AND SOUTHERN STREAM TROUGHING PHASE AND TRACK INTO THE
WEST. COOLER TEMPERATURES, LOWER ELEVATION RAIN AND HIGHER
ELEVATION SNOW, AND WINDY CONDITIONS ARE ALL EXPECTED FOR THE WEST
COAST TO THE ROCKIES EARLY NEXT WEEK. INCREASED PRECIPITATION IS
ALSO LIKELY FOR THE OHIO VALLEY/GREAT LAKES BY MONDAY-TUESDAY WITH
A FRONTAL SYSTEM OR TWO AHEAD OF THIS TROUGH.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE IS AGREEABLE WITH THE LARGER SCALE ASPECTS OF THE
UPPER PATTERN THIS WEEKEND INTO EARLY NEXT WEEK, INCLUDING A
TROUGH AXIS THAT MOVES QUICKLY OUT OF THE EAST, MEAN RIDGING
BEHIND IT (BRIEFLY FLATTENING ON ITS NORTHERN SIDE SUNDAY WITH A
POSSIBLE SHORTWAVE), AND AN UPPER LOW IN THE EASTERN PACIFIC THAT
GETS JOINED BY NORTHERN STREAM TROUGHING WITH POTENT ENERGY COMING
INTO THE PACIFIC NORTHWEST. THE GREATEST MODEL DIFFERENCES ARISE
IN THE WEST WITH THE TIMING OF THE SOUTHERN STREAM UPPER
LOW/TROUGH APPROACHING CALIFORNIA. THE NEWER 00Z MODELS HAVE
SLOWED DOWN THE APPROACH OF THIS FEATURE EARLY NEXT WEEK COMPARED
TO THE 12/18Z CYCLE, SO THERE IS STILL SOME MODEL WAFFLING GOING
ON. AT LEAST THE MODELS ARE GENERALLY AGREEABLE REGARDING THE
SOUTHERN STREAM AND NORTHERN STREAM TROUGHING COMBINING AND
TRACKING EASTWARD TOWARD THE CENTRAL U.S. INTO MIDWEEK, JUST WITH
SOME TIMING DIFFERENCES. WITH THE 12/18Z MODEL CYCLE, THE 18Z GFS
WAS SLOWER/FARTHER WEST WITH THE TROUGH BY DAY 7/WEDNESDAY
COMPARED TO THE 12Z GFS AND ECMWF AND CMC. HOWEVER, THE 18Z GFS
SEEMED TO ALIGN BETTER WITH THE ENSEMBLE MEANS WITH THE TROUGH
AXIS AND SURFACE LOW POSITION, SO DID NOT ELIMINATE THE IT FROM
THE BLEND EVEN THOUGH IT INITIALLY SEEMED LIKE AN OUTLIER AMONG
THE DETERMINISTIC RUNS, WHICH WAS LIKELY GOOD NOW SEEING THE
SLOWER 00Z GUIDANCE. OVERALL THE WPC FORECAST USED A BLEND OF THE
DETERMINISTIC GUIDANCE EARLY WITH A GRADUAL INCREASE OF GEFS AND
EC ENSEMBLE MEANS TO HALF BY DAY 7. THIS MAINTAINED GOOD
CONTINUITY WITH THE PREVIOUS WPC FORECAST THROUGH DAYS 3-6.
..WEATHER/HAZARDS HIGHLIGHTS
AN UPPER LOW AND ITS SURFACE REFLECTION LOOK TO MEANDER IN THE
EASTERN PACIFIC LATE THIS WEEK, PERHAPS REACHING CLOSE ENOUGH TO
CALIFORNIA TO PROVIDE SOME SHOWER ACTIVITY. BUT BY SUNDAY INTO
MONDAY MODEL GUIDANCE IS MORE AGREEABLE THAT PRECIPITATION SHOULD
SPREAD INTO THE PACIFIC NORTHWEST AND CALIFORNIA WITH SOME
MOISTURE SPREADING FARTHER INLAND INTO THE INTERMOUNTAIN WEST.
SNOW AND RAIN SHOULD CONTINUE TO INCREASE IN INTERIOR PARTS OF THE
WEST INTO MONDAY-TUESDAY. HEAVY SNOW WITH THE HIGHEST LIKELIHOOD
FOR IMPACTS IS IN THE CASCADES SUNDAY-TUESDAY, BUT THE SNOW WILL
LIKELY CAUSE AT LEAST MINOR IMPACTS TO MUCH OF THE HIGHER
ELEVATION AREAS OF THE SIERRA INTO THE INTERMOUNTAIN WEST AND
ROCKIES. GUSTY WINDS ARE FORECAST FOR THE INTERIOR WEST BEHIND A
COUPLE OF COLD FRONTS ON MONDAY-TUESDAY AS WELL.
FARTHER EAST, LIGHT RAIN AND SNOW ARE POSSIBLE SATURDAY FOCUSED IN
THE SOUTHERN APPALACHIANS. A COLD FRONT TRACKING THROUGH THE
NORTHEASTERN U.S. COULD SPREAD SOME LIGHT TO MODERATE
PRECIPITATION FROM THE OHIO VALLEY INTO THE NORTHERN/CENTRAL
APPALACHIANS AND THE NORTHEAST ON SUNDAY. THEN AHEAD OF THE
APPROACHING UPPER TROUGH AND COLD FRONT, PRECIPITATION CHANCES
WILL INCREASE LATE MONDAY INTO TUESDAY IN THE MIDWEST TO THE OHIO
VALLEY AND GREAT LAKES. MOST PRECIPITATION WILL BE IN THE FORM OF
RAIN GIVEN THE ANOMALOUS WARMTH, BUT SOME SNOW IN THE NORTHEAST
AHEAD OF THE SYSTEM AND SOME SNOW ON THE BACKSIDE OF THE LOW IN
THE NORTH-CENTRAL U.S. IS POSSIBLE, THOUGH WITH LOW CONFIDENCE.
RAINFALL AMOUNTS COULD BE LOCALLY HEAVY IN THE OHIO VALLEY.
THE CENTRAL U.S. WILL SEE QUITE A MILD TO WARM WEEKEND TO EARLY
NEXT WEEK UNDERNEATH AN UPPER RIDGE. TEMPERATURES OF 15-25 DEGREES
ABOVE AVERAGE IN THE NORTH-CENTRAL U.S. ON SATURDAY WILL ONLY
INCREASE IN COVERAGE AND MAGNITUDE BY EARLY NEXT WEEK. HIGHS AND
LOWS THAT ARE 20-35 DEGREES ABOVE NORMAL SHOULD EXPAND SOUTHWARD
INTO THE PLAINS AND MISSISSIPPI VALLEY EARLY NEXT WEEK. THIS PUTS
ACTUAL TEMPERATURES INTO THE 80S AND EVEN 90S IN TEXAS
MONDAY-TUESDAY WHILE 60S REACH AS FAR NORTH AS SOUTH DAKOTA AND
IOWA. A GRADUAL EASTWARD SPREAD/SHIFT SHOULD WARM THE SOUTHEAST IN
TO THE 70S NEXT WEEK. THE CENTRAL U.S. SHOULD MODERATE CLOSER TO
NORMAL BY MIDWEEK WHILE THE HIGHEST ANOMALIES SHIFT INTO THE EAST,
AFTER A COOL WEEKEND AND GRADUAL WARM-UP. MEANWHILE THE WEST IS
FORECAST TO SEE NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES LATE
WEEK INTO THE WEEKEND, BUT COOLING TO BELOW NORMAL PARTICULARLY IN
TERMS OF HIGHS BY MONDAY-TUESDAY AS UPPER TROUGHING COMES IN.
TATE
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, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY
MESSAGES ARE AT:
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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