876
FXUS02 KWBC 040606
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
206 AM EDT MON MAY 4 2026
VALID 12Z THU MAY 07 2026 - 12Z MON MAY 11 2026
..GENERAL OVERVIEW
A BROAD UPPER-LEVEL CLOSED LOW OVER EASTERN CANADA WILL CONTINUE
TO DRIVE BROAD CYCLONIC FLOW AND REPEATED TROUGH REINFORCEMENT
THROUGH THE PERIOD. THIS PATTERN WILL BRING A STRETCH OF COOL,
UNSETTLED WEATHER ACROSS CENTRAL/EASTERN U.S. THE PROGRESSIVE COLD
FRONT WILL CONTINUE TO MOVE ACROSS EASTERN U.S. BY LATE WEEK,
BRINGING SHOWERS AND THUNDERSTORMS ACROSS EASTERN U.S. ALTHOUGH THE
MAIN FRONT MOVES OFFSHORE BY THE WEEKEND, THE EMBEDDED SHORTWAVE
TROUGHS WILL CONTINUE SHOWER ACTIVITY ALONG PARTS OF EASTERN U.S.
INTO THE WEEKEND. THE REMNANTS OF THE FRONT WILL LINGER ACROSS
LOWER MISSISSIPPI VALLEY INTO SOUTHEAST, BRINGING ADDITIONAL
RAINFALL ACROSS THE AREA. BELOW NORMAL TEMPERATURES WILL CONTINUE
ACROSS THE GREAT LAKES INTO THE NORTHEAST THROUGH THE WEEKEND,
WHILE A WARMING TREND SPREAD ACROSS MUCH OF WESTERN/CENTRAL U.S.
..GUIDANCE/PREDICTABILITY ASSESSMENT
LATEST MODEL GUIDANCE CONTINUES TO SHOW GOOD AGREEMENT OF THE
UPPER- LEVEL TROUGH/LOW OVER EASTERN CANADA WITH SOME DIFFERENCES
IN TIMING AND AMPLITUDE OF A FEW SHORTWAVE ENERGIES TOWARD DAY 5,
ESPECIALLY WITH THE GFS SHOWING A FASTER PROGRESSION THAN THE CMC
AND ECMWF. OVER WESTERN U.S., THE GFS ALSO SHOWS SOME LARGER
DIFFERENCES WITH THE RIDGE OVER PACIFIC NORTHWEST AND THE
LOW/TROUGH OVER THE SOUTHWEST COMPARED TO CMC AND ECMWF. THE
ENSEMBLE MEANS DOES A DECENT JOB WITH SMOOTHING SOME OF THESE
DIFFERENCES. THEREFORE, THE WPC FORECAST WAS BASED ON A MULTI-MODEL
BLEND WITH THE GFS/CMC/ECMWF/UKMET AND ECAIFS FOR THE THE FIRST
PORTION OF THE PERIOD. LATER IN THE PERIOD, THE ENSEMBLE MEANS WERE
INCORPORATED TO ACCOUNT FOR SOME OF THE TIMING AND AMPLITUDE
DIFFERENCES.
..WEATHER/HAZARDS HIGHLIGHTS
THE BROAD UPPER-LEVEL LOW HOVERING OVER EASTERN CANADA WILL
CONTINUE TO EJECT SHORTWAVE ENERGY NEAR THE BASE OF THE MEAN TROUGH
ACROSS MUCH OF EASTERN AND SOUTHERN U.S. THE LOW WILL SERVE AS AN
ANCHOR FOR MAINTAINING CYCLONIC FLOW AND REINFORCING COOLER AIR
SOUTHWARD INTO EASTERN U.S. AT THE SURFACE, THE PRIMARY COLD FRONT
ASSOCIATED WITH THIS TROUGH WILL MOVE EASTWARDS AND STRETCH ACROSS
THE LOWER MISSISSIPPI VALLEY INTO THE NORTHEAST ON THURSDAY. THE
BOUNDARY WILL INTERACT WITH MOIST GULF MOISTURE, WHICH WILL LEAD
TO ADDITIONAL SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN PLAINS
INTO SOUTHEAST. IN ADDITION, THE INCREASING DEEP-LAYER SHEAR AND
MODEST INSTABILITY WILL SUPPORT ORGANIZED CONVECTION AND CHANCES
FOR HEAVY RAINFALL ALONG THE FRONTAL BOUNDARY, PARTICULARLY OVER
SOUTHEAST. WITH FLOODING CONCERNS OVER THE AREA, A MARGINAL RISK
HAS BEEN INTRODUCED FOR DAY 4/THURSDAY ACROSS SOUTHERN ALABAMA. IN
ADDITION, GUSTY NORTHWEST WINDS MAY DEVELOP BEHIND THE FRONT FROM
THURSDAY INTO FRIDAY.
HEADING INTO FRIDAY, THE TRAILING END OF THE COLD FRONT WILL STALL
OVER NEAR THE GULF COAST AND SOUTHEAST, BRING ADDITIONAL SHOWERS
AND THUNDERSTORMS THROUGH THE WEEKEND. FURTHERMORE, AS THE FRONT
EXITS OFF THE COAST, WRAPAROUND MOISTURE AND EMBEDDED SHORTWAVES
WILL BRING OCCASIONAL SHOWERS ACROSS THE GREAT LAKES, INTERIOR
NORTHEAST, AND CENTRAL APPALACHIAN THROUGH THE WEEKEND.
MEANWHILE, BELOW AVERAGE TEMPERATURES WILL CONTINUE ACROSS EASTERN
U.S. BEHIND THE COLD FRONT FROM THURSDAY THROUGH FRIDAY.
FROST/FREEZE CONDITIONS WILL CONTINUE ACROSS THE UPPER MIDWEST/GREAT
LAKES AND NORTHEAST THROUGH FRIDAY MORNING AND THE NORTHERN
BORDERS OF NEW ENGLAND THROUGH SATURDAY MORNING. WITH THE COLD
TEMPERATURES, THERE IS A SLIGHT CHANCE FOR SOME MIXED PRECIPITATION
OVER ISOLATED HIGH-ELEVATION AREAS OVER THE NORTHEAST, BUT IMPACTS
WILL BE MINIMAL.
OVER WESTERN U.S., A SHORTWAVE ENERGY WILL PUSH A FRONTAL BOUNDARY
INTO NORTHERN- CENTRAL ROCKIES/PLAINS ON THURSDAY, BRINGING A
CHANCE FOR LOW-ELEVATION SHOWERS AND HIGH-ELEVATION SNOW THROUGH
THE WEEKEND. IN ADDITION, DEEP BOUNDARY LAYER MIXING WILL BRING
GUSTY WINDS ACROSS THE AREA ON THURSDAY. THE FRONT WILL CONTINUE TO
STRENGTHEN AS IT MOVES EASTWARD, EXPANDING THE CHANCES FOR LIGHT
PRECIPITATION ACROSS CENTRAL U.S. BY SUNDAY. OVER INTO THE PACIFIC
NORTHWEST/WEST COAST, A RIDGING PATTERN CONTINUES TO PUSH INLAND
EARLY IN THE PERIOD AND WILL GRADUALLY MOVE SOUTHEASTWARD INTO
CENTRAL U.S. THROUGH THE WEEKEND. THIS WILL BRING 10-15 DEGREES
ABOVE AVERAGE TEMPERATURES WITH HIGHS MOSTLY IN THE 80S AND 90S.
OUDIT
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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