441
FXUS02 KWBC 280722
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
322 AM EDT THU MAY 28 2026
VALID 12Z SUN MAY 31 2026 - 12Z THU JUN 04 2026
...HEAVY RAIN AND THUNDERSTORM THREATS CONTINUE FOR THE SOUTHEAST
AND THE NORTHERN ROCKIES LATE WEEKEND INTO EARLY NEXT WEEK...
..OVERVIEW
AN AMPLIFIED UPPER-LEVEL SYNOPTIC PATTERN WILL REMAIN IN PLACE
INTO EARLY NEXT WEEK, BEFORE TURNING MORE ZONAL MID TO LATE WEEK.
OVERALL, THE GENERAL PATTERN WILL FEATURE TROUGHING OVER BOTH THE
WEST AND EAST WITH RIDGING IN BETWEEN. THE TROUGH OVER THE WEST
WILL CLOSE OFF INTO A BROAD UPPER LOW AND SPIN OVER THE NORTHERN
ROCKIES, BRINGING LOW ELEVATION HEAVY RAIN AND MOUNTAIN SNOW SUNDAY
INTO MONDAY. UNSEASONABLY LOW HEIGHTS OVER THE EAST WILL BE
REINFORCED THROUGH EARLY TO MIDWEEK AS SEVERAL DISTURBANCES ROTATE
WITHIN AND AROUND A PARENT TROUGH/CLOSED LOW OVER ATLANTIC CANADA.
THE RELATIVELY COOL AIR MASS ACROSS THE NORTHEAST AND EAST-
CENTRAL U.S. WILL KEEP HEAT AND HUMIDITY SUPPRESSED TO THE SOUTH.
THE RESULTING FRONTAL BOUNDARY DRAPED ACROSS THE SOUTHEAST COMBINED
WITH SOUTHERN STREAM ENERGY WILL ALLOW FOR THE PERSISTENCE OF A
GENERALLY WET AND STORMY PATTERN ACROSS MUCH OF THE REGION. LATER
IN THE PERIOD, STORMY WEATHER FROM PARTS OF THE WEST BUILDS INTO
THE PLAINS BEFORE ADVANCING EASTWARD WITH TIME.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST MODELS ARE IN GOOD AGREEMENT OF THEIR DEPICTIONS OF THE
LARGE SCALE PATTERN THROUGH THE MEDIUM RANGE PERIOD, HIGHLIGHTING
AN AMPLIFIED SOLUTION THAT SLOWLY BECOMES MORE ZONAL. SMALLER
SPATIAL AND TEMPORAL DIFFERENCES, PARTICULARLY WITH RESPECT TO THE
TRANSITION AWAY FROM A BLOCKY PATTERN MID TO LATE WEEK, LEADS TO
SOME LINGERING UNCERTAINTY WITH SYSTEM/FRONTAL PLACEMENT AND
SENSIBLE WEATHER IMPACTS. HOWEVER, FOR THE MOST PART, A BLEND OF
THE DETERMINISTIC MODELS AND ENSEMBLE MEANS SEEMED TO PROVIDE A
SOLID FORECAST BASIS THAT RETAINED CONTINUITY AND MITIGATED ANY
LARGER DIFFERENCES. THIS SOLUTION IS GENERALLY IN LINE WITH THE NBM
AND ALSO FITS WITH NATIONAL HURRICANE CENTER INSIGHT THAT
CONTINUES TO DISCOUNT TROPICAL MOISTURE FEED AND DEVELOPMENT
POTENTIAL BY RECENT GFS RUNS NORTHWARD FROM THE CARIBBEAN.
..WEATHER/HAZARDS HIGHLIGHTS
A VERY WARM, HUMID, AND UNSTABLE AIRMASS SOUTH OF A WAVY FRONTAL
BOUNDARY WILL KEEP MUCH OF THE SOUTH AND SOUTHEAST ACTIVE WITH
DAILY RAIN AND THUNDERSTORM CHANCES FROM LATE WEEKEND INTO EARLY
NEXT WEEK. THE POTENTIAL FOR SCATTERED CLUSTERS OF THUNDERSTORMS
CONTAINING HIGH RAINFALL RATES COMBINED WITH WHAT HAS ALREADY BEEN
A WET PATTERN ACROSS THIS REGION INDICATES THAT ISOLATED FLASH
FLOODING COULD BE A CONCERN, PARTICULARLY FOR FLOOD PRONE AREAS. AS
A RESULT, FOR DAY 4/SUNDAY AND DAY 5/MONDAY, MARGINAL RISK AREAS
HAVE BEEN INTRODUCED FOR PARTS OF THE SOUTHEAST INTO FLORIDA.
MEANWHILE, AN UPPER TROUGH THAT IS FORECAST TO CLOSE OFF INTO A
CUT-OFF LOW OVER THE NORTHERN ROCKIES WILL BRING WIDESPREAD LOW
ELEVATION HEAVY RAIN AND SOME HIGH ELEVATION MOUNTAIN SNOW FROM
LATE WEEKEND INTO EARLY NEXT WEEK. THE SIGNAL FOR HEAVY RAINFALL
REMAINS ROBUST ENOUGH TO MAINTAIN THE DAY 4/SUNDAY MARGINAL RISK
ACROSS A LARGE PORTION OF MONTANA AND A PART OF NORTHERN WYOMING,
WITH INTENSITY WANING HEADING INTO MONDAY AND TUESDAY. RAINFALL AND
THUNDERSTORM CHANCES ALSO INCREASE ACROSS THE PLAINS MID TO LATE
WEEK AS THE CUT-OFF LOW OPENS BACK UP INTO A WAVE AND BEGINS TO
MOVE EASTWARD.
MODERATING TEMPERATURES ARE EXPECTED ACROSS THE WEST INTO NEXT
WEEK FOLLOWING A PERIOD OF COOLER THAN NORMAL TEMPERATURES
ASSOCIATED WITH INCREASED CLOUD COVER AND PRECIPITATION. ABOVE
NORMAL WARMTH WILL GENERALLY BE CONFINED TO THE CENTRAL U.S. WHERE
UPPER LEVEL RIDGING IS MOST PERSISTENT. IN CONTRAST, NEAR TO
SLIGHTLY BELOW NORMAL TEMPERATURES ARE EXPECTED ACROSS THE
NORTHEAST AND MID- ATLANTIC AS PERIODIC SYSTEMS BRING RAIN CHANCES
AND REINFORCING PUSHES OF COOL AIR.
MILLER
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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