835
FXUS02 KWBC 201854
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
154 PM EST TUE FEB 20 2024
VALID 12Z FRI FEB 23 2024 - 12Z TUE FEB 27 2024
..OVERVIEW
AN UPPER RIDGE TRAVERSING THE COUNTRY LATE THIS WEEK INTO EARLY
NEXT WEEK WILL SPREAD MUCH ABOVE NORMAL TEMPERATURES PARTICULARLY
TO THE PLAINS AND MIDWEST. TROUGHING WILL BE IN PLACE ACROSS THE
EAST LATE THIS WEEK AHEAD OF THE RIDGE, WITH SOME PRECIPITATION
ACROSS THE EASTERN SEABOARD FRIDAY AND COOLER TEMPERATURES BY
SATURDAY BEHIND A COLD FRONT, BEFORE TRANSITIONING TO MORE ZONAL
FLOW. 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.
..GUIDANCE/PREDICTABILITY ASSESSMENT
OVERALL, THE MODEL GUIDANCE CONTINUES TO SHOW ABOVE AVERAGE
AGREEMENT ON THE LARGE SCALE PATTERN, BUT SOME INCONSISTENCIES IN
THE DETAILS. THERE ARE SOME MINOR DIFFERENCES EARLY ON WITH WEAK
SHORTWAVES THROUGH THE NORTHEAST BUT A GENERAL MODEL COMPROMISE
SEEMS TO SMOOTH THESE OUT AND PROVIDE A GOOD STARTING POINT. OUT
WEST, THE SUNDAY-TUESDAY PERIOD PRESENTS SOME UNCERTAINTIES WITH
NORTHERN STREAM ENERGY THROUGH THE PACIFIC NORTHWEST AND THEN THE
DETAILS OF EVENTUAL PHASING WITH THE UPPER LOW THAT MEANDERS OFF
THE SOUTHERN CALIFORNIA COAST LATE THIS WEEK/WEEKEND. BY NEXT
TUESDAY, THE CMC IS NOTICEABLY FASTER THAN THE GFS/ECMWF (AND
ENSEMBLE MEANS) WITH AN EVENTUAL AMPLIFIED TROUGH THROUGH THE WEST
AND WAS EXCLUDED FROM THE LATE PERIOD BLEND TODAY. WPC USED A
BLEND OF THE DETERMINISTIC GUIDANCE FOR THE FIRST HALF OF THE
PERIOD, EVENTUALLY TRANSITIONING TO A 50/50 BLEND OF THE
DETERMINISTIC (GFS AND ECMWF) WITH THE ENSEMBLE MEANS BY DAY 7.
THIS ALSO MAINTAINED GOOD CONTINUITY WITH THE PREVIOUS WPC
FORECAST AS WELL.
..WEATHER/HAZARDS HIGHLIGHTS
LIGHT TO MODERATE PRECIPITATION IS FORECAST FOR THE EASTERN
SEABOARD ON FRIDAY AHEAD OF A COLD FRONT. HIGHER ELEVATIONS OF NEW
YORK AND NEW ENGLAND HAVE RELATIVELY HIGHER PROBABILITIES OF
SEEING NOTABLE SNOW WITH THIS ACTIVITY BUT THE DETAILS OF THE
EXACT LOW TRACK AND TEMPERATURES WILL DETERMINE PLACEMENT AND
AMOUNTS OF SNOW. BRISK WINDS ARE ALSO POSSIBLE FOR NEW ENGLAND
PARTICULARLY LATE FRIDAY INTO SATURDAY AS THE SURFACE LOW
STRENGTHENS. BEHIND THIS SYSTEM, PARTS OF THE GREAT LAKES MAY SEE
MOSTLY LIGHT SNOW FROM A COMBINATION OF LAKE EFFECT AND LAKE
ENHANCED ACTIVITY CAUSED BY NEARBY FRONTS THIS WEEKEND INTO EARLY
NEXT WEEK.
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 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, WITH POTENTIAL FOR GUSTY WINDS TO ACCOMPANY THIS
OVERALL SYSTEM. ANOTHER LOW PRESSURE/FRONTAL SYSTEM ALSO SHOULD
PROVIDE FORCING TO INCREASE PRECIPITATION (MAINLY IN THE FORM OF
RAIN GIVEN THE ANOMALOUS WARMTH) IN THE MIDWEST.
WARMER THAN AVERAGE TEMPERATURES BY 10-20 DEGREES IN THE CENTRAL
U.S. ON FRIDAY LOOK TO ONLY INCREASE IN COVERAGE AND MAGNITUDE BY
THE WEEKEND AND EARLY NEXT WEEK. TEMPERATURES OF 20-30F ABOVE
AVERAGE WILL STRETCH FROM THE NORTHERN PLAINS/UPPER MIDWEST
SATURDAY 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 50S AND POSSIBLY EVEN 60S REACH THE
DAKOTAS. A GRADUAL EASTWARD SPREAD/SHIFT SHOULD WARM THE SOUTHEAST
IN TO THE 70S NEXT WEEK. THE EAST LOOKS TO BE ABOVE AVERAGE FRIDAY
BUT NEAR TO BELOW AVERAGE SATURDAY BEHIND A COLD FRONT, AND
GRADUALLY WARMING AGAIN NEXT WEEK. 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.
SANTORELLI/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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