806
FXUS02 KWBC 030528
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
128 AM EDT SUN MAY 3 2026
VALID 12Z WED MAY 06 2026 - 12Z SUN MAY 10 2026
..GENERAL OVERVIEW
THE AMPLIFIED AND SLOW MOVING UPPER-LEVEL CLOSED LOW OVER
SOUTHEASTERN CANADA CONTINUES TO DRIVE BROAD CYCLONIC FLOW AND
REPEATED TROUGH REINFORCEMENT ACROSS CENTRAL/EASTERN U.S. NEXT
WEEK. THIS WILL BRING A STRETCH OF COOL, UNSETTLED WEATHER ACROSS
THE AREA. THE ASSOCIATED COLD FRONT WILL CONTINUE TO MOVE SOUTH-
SOUTHEAST AND WILL PRODUCE SHOWERS AND THUNDERSTORMS ACROSS EASTERN
U.S., WITH POTENTIAL FLOODING CONCERNS. FURTHERMORE, A SOUTHERN
STREAM UPPER TROUGH/CLOSED LOW MOVES ACROSS THE SOUTHWEST INTO THE
PLAINS, BRINGING CHANCES FOR STORMS ACROSS THE PLAINS/MISSISSIPPI
VALLEY. BY MIDWEEK, BELOW NORMAL TEMPERATURES WILL CONTINUE ACROSS
MUCH OF NORTHERN AND CENTRAL U.S., BEFORE MODERATING BY THE END OF
THE WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST MODEL GUIDANCE CONTINUES TO SHOW GOOD AGREEMENT WITH
THE LARGE- SCALE FEATURES THROUGH DAY 5, WITH DIFFERENCES IN REGARD
TO TIMING AND AMPLITUDE OF THE SHORTWAVE FEATURES ASSOCIATED WITH
THE TROUGH/LOW OVER WEST/SOUTHWEST. THE DETERMINISTIC MODELS SEEM
TO SHOW SOME IMPROVEMENT WITH THE SMALLER SCALE FEATURES WITH THE
TROUGH/LOW OVER SOUTHEASTERN CANADA. LATER IN THE PERIOD, CMC AND
ECMWF SEEMS TO SHOW BETTER AGREEMENT, WHERE AS THE GFS SEEMED TO
SHOW FASTER PROGRESSION WITH SOME OF THE LARGE-SCALE FEATURES,
ESPECIALLY OVER THE WEST. THEREFORE, THE WPC FORECAST CONSISTED OF
A EVEN MULTI-MODEL BLEND WITH CMC/GFS/ECMWF/UKMET AND EC-AIFS FOR
THE FIRST PORTION OF THE PERIOD, WHILE PHASING IN MORE WEIGHT ON
THE ENSEMBLE MEANS TO SMOOTH OUT SOME OF THE DIFFERENCES.
..WEATHER/HAZARDS HIGHLIGHTS
THE PROLONGED UPPER-LEVEL LOW WILL CONTINUE TO HOVER OVER CENTRAL
TO SOUTHEASTERN CANADA THROUGH THE MEDIUM-RANGE PERIOD, BRINGING A
SERIES OF SHORTWAVES ROTATING AROUND THE BASE OF THE MEAN TROUGH.
THIS WILL SUPPORT MULTIPLE FRONTAL PASSAGES AND WAVES OF
PRECIPITATION ACROSS CENTRAL/EASTERN U.S. THROUGH THE WEEK. AHEAD
OF THE COLD FRONT, EXPECT SHOWERS AND THUNDERSTORMS ACROSS THE
MISSISSIPPI VALLEY, OHIO/TENNESSEE VALLEY, GREAT LAKES AND
NORTHEAST ON WEDNESDAY. IN ADDITION, GUSTY WINDS MAY DEVELOP ALONG
FRONTAL PASSES OVER THE SOUTHEAST, MID-ATLANTIC, OHIO/TENNESSEE
VALLEY, AND NORTHEAST.
THE COLD FRONT WILL CONTINUE TO MOVE SOUTHEASTWARD AND WILL PULL
WARM GULF MOISTURE ALONG THE BOUNDARY, WHICH WILL SUPPORT SHOWERS
AND THUNDERSTORMS ACROSS THE MID- SOUTH, MID- ATLANTIC, AND
SOUTHEAST BY WEDNESDAY. WITH THE COMBINATION OF UPPER-LEVEL
FORCING/INSTABILITY, AN INFLUX OF MOISTURE, AND ORGANIZED
THUNDERSTORMS PRODUCING HEAVY RAINFALL ALONG THE FRONT, LOCALIZED
FLOODING MAY BE POSSIBLE ACROSS THE LOWER MISSISSIPPI VALLEY INTO
THE OHIO/TENNESSEE VALLEY WEDNESDAY INTO THURSDAY. THIS FLOOD
THREAT IS REPRESENTED BY THE MARGINAL RISK ON THE DAY 4/WEDNESDAY
ERO. GOING INTO THURSDAY, THE FRONT PUSHES CLOSER TO THE EAST
COAST WITH A TRAILING FRONT STRETCHING ACROSS THE MID-ATLANTIC AND
SOUTHEAST. THIS WILL BRING SOME ADDITIONAL SHOWERS AND
THUNDERSTORMS ALONG THE BOUNDARY, WITH HIGHER RAINFALL TOTALS OVER
SOUTHEAST.
THE COLD AIR PUSHES INTO THE NORTHERN AND CENTRAL U.S. BEHIND THE
COLD FRONT AND CYCLONIC FLOW, WHICH WILL BRING BELOW NORMAL
TEMPERATURES ACROSS THE NORTHERN/CENTRAL PLAINS INTO MUCH OF THE
EASTERN U.S., WITH FROST/FREEZE CONDITIONS ACROSS NORTHERN/CENTRAL
PLAINS INTO THE UPPER MIDWEST/GREAT LAKES. WITH THE COLD
TEMPERATURES, THERE IS A SLIGHT CHANCE FOR SOME MIXED
PRECIPITATION OVER SOME ISOLATED HIGHER- ELEVATION AREAS NEAR THE
UPPER MIDWEST/GREAT LAKES BUT IMPACTS WILL BE MINIMAL. OVER
NORTHERN/CENTRAL PLAINS INTO THE GREAT LAKES, TEMPERATURES WILL
DROP 15-20 DEGREES BELOW AVERAGE BY MIDWEEK. BY LATE WEEK, THE
BELOW NORMAL TEMPERATURES PUSHES TOWARDS EASTERN U.S., WHILE
TEMPERATURES MODERATE FOR CENTRAL U.S.
OVER THE WESTERN U.S., THE PACIFIC UPPER LOW/TROUGH WILL CONTINUE
TO MOVE ACROSS THE SOUTHWEST EARLY IN THE PERIOD, THEN GRADUALLY
EJECTS INTO THE PLAINS. THIS WILL BE BRING SOME LOW ELEVATION
SHOWERS AND POSSIBLE THUNDERSTORMS, AS WELL AS SOME HIGH ELEVATION
SNOW ACROSS PARTS OF ROCKIES/PLAINS ON WEDNESDAY. THE COLD FRONT
WILL BRING 15-25 DEGREES BELOW NORMAL TEMPERATURES ACROSS THE FOUR
CORNERS ON WEDNESDAY. THIS WILL FACILITATE COLD RAIN FOR THE FRONT
RANGE OF COLORADO TO SOUTHERN WYOMING AND HEAVY SNOW FOR THE
COLORADO ROCKIES. THE FRONTAL SYSTEM AND SHORTWAVE ENERGY WILL ALSO
BRING SOME GUSTY WINDS ACROSS ROCKIES/PLAINS ON WEDNESDAY. OVER
THE PACIFIC NORTHWEST, A RIDGE WILL PUSH INLAND, BRINGING A WARMING
TREND. AS THE RIDGE CONTINUES TO MOVE EASTWARD, ABOVE NORMAL
TEMPERATURES WILL RETURN ACROSS MUCH OF WESTERN U.S. LATER NEXT
WEEK.
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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