432
FXUS02 KWBC 251710
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
110 PM EDT MON MAY 25 2026
VALID 12Z THU MAY 28 2026 - 12Z MON JUN 01 2026
...HEAVY RAIN AND THUNDERSTORMS EXPECTED TO CONTINUE ACROSS MUCH
OF THE SOUTHERN U.S...
..OVERVIEW
MULTIPLE PIECES OF ENERGY WITHIN A SOUTHERN STREAM SHORTWAVE WILL
PASS THROUGH THE SOUTH-CENTRAL U.S. LATER THIS WEEK, PROVIDING LIFT
FOR WIDESPREAD RAIN AND THUNDERSTORMS IN A MOIST AND UNSTABLE
ENVIRONMENT STRETCHING THROUGH THE SOUTHEAST AS WELL. HEAVY RAIN IS
LIKELY TO FOCUS MORE INTO THE MIDDLE TO LOWER MISSISSIPPI VALLEY
MIDWEEK, POTENTIALLY OVER AREAS THAT WILL ALREADY HAVE WET
ANTECEDENT CONDITIONS, LEADING TO SOME CONCERN FOR FLOODING. OUT
WEST, A CLOSED UPPER LOW SHOULD BE ATOP THE GREAT BASIN MID TO LATE
WEEK, RESULTING IN COOLER TEMPERATURES AND PRECIPITATION FOR THE
WEST AS IT MEANDERS WHILE WEAKENING. A BLOCKY UPPER RIDGE IS SET TO
STRETCH ACROSS THE NORTH- CENTRAL U.S. AND BRING ABOVE AVERAGE
TEMPERATURES THROUGH MUCH OF THE PERIOD. MEANWHILE A COUPLE OF
UPPER TROUGHS/LOWS SHOULD PUSH THROUGH THE NORTHEAST AND ALLOW FOR
PRECIPITATION CHANCES.
..GUIDANCE/PREDICTABILITY ASSESSMENT
OVERALL GOOD MODEL AGREEMENT CONTINUES FOR THE LARGE-SCALE DYNAMICS
THROUGH THE PERIOD WITH THE CLOSED UPPER LOW OVER WESTERN U.S. AND
TROUGHING OVER NORTHEAST U.S., WHILE A BLOCKING PATTERN BECOMES
MORE DEFINED BY THE END OF THE WEEK. THE DIFFERENCES AMONGST THE
MODELS ARISE WITH THE SMALL SCALE FEATURES, ESPECIALLY ACROSS THE
SOUTHERN TIER WITH A SHORTWAVE ENERGY MOVING EASTWARD, WHICH CAN
AFFECT SENSIBLE WEATHER. HEADING INTO THE WEEKEND, A SOUTHERN
STREAM ENERGY EJECTS ACROSS THE SOUTH- CENTRAL U.S. CMC SHOWS SOME
DIFFERENCES COMPARED TO THE GFS AND ECMWF IN RESPECT TO THE
LOCATION OF THE TROUGH, BUT THE ENSEMBLE MEANS SOLUTION TENDS TO
SMOOTH OUT SOME OF THE AMPLITUDE AND TIMING DIFFERENCES. THE WPC
FORECAST UTILIZES A BLEND OF ECMWF/CMC/GFS/EC- AIFS/UKMET FOR THE
FIRST PORTION OF THE PERIOD, WITH INCORPORATING MORE WEIGHT ON A
BLEND OF THE THE ENSEMBLE MEANS TO ACCOUNT FOR THE SMALL SCALE
DIFFERENCES TOWARDS THE LATTER HALF OF THE PERIOD.
..WEATHER/HAZARDS HIGHLIGHTS
PERSISTENT SOUTHERN STREAM ENERGY WILL CONTINUE TO KEEP MUCH OF
THE SOUTH ACTIVE AND UNSETTLED INTO THE WEEKEND WITHIN A VERY MOIST
AND UNSTABLE ENVIRONMENT AND DAILY THUNDERSTORM CHANCES. BOTH THE
DAY 4/THURSDAY AND DAY 5/FRIDAY EROS SHOW BROAD MARGINAL RISKS
ACROSS THE MIDDLE-LOWER MISSISSIPPI VALLEY AND INTO PARTS OF THE
TENNESSEE VALLEY AND DEEP SOUTH WHERE MOISTURE ANOMALIES ARE HIGH
WITH SUFFICIENT INSTABILITY. MODELS CONTINUE TO SHOW SOME
UNCERTAINTY WITH THE PLACEMENT OF THE MOISTURE, WHICH WILL IMPACT
WHERE THE HEAVIEST QPF MAY FOCUS, BUT FUTURE SLIGHT RISK WILL NOT
BE OUT OF THE QUESTION. WET WEATHER IS LIKELY ACROSS THE SOUTHEAST
INTO FLORIDA AS WELL, WITH A MARGINAL RISK FOR PARTS OF SOUTHERN
FLORIDA THURSDAY AND FRIDAY IN A FAVORABLE PATTERN FOR HEAVY
RAINFALL. AFTER WHAT HAS BEEN A VERY WET PERIOD FOR MUCH OF TEXAS,
CONDITIONS SHOULD FINALLY SETTLE ACROSS THE REGION LATER THIS WEEK
AS THE OVERALL PATTERN SHIFTS SLIGHTLY EAST. HOWEVER, RAINFALL MAY
BE RENEWED AGAIN ACROSS TEXAS BY THE WEEKEND.
UPPER TROUGHING MEANDERING AROUND THE GREAT BASIN WITH A FRONTAL
SYSTEM AHEAD OF IT WILL ALLOW FOR INCREASED PRECIPITATION ACROSS
THE PACIFIC NORTHWEST TO INTERMOUNTAIN WEST FOR MULTIPLE DAYS. SNOW
IS POSSIBLE ACROSS HIGHER ELEVATIONS, WITH HIGHEST AMOUNTS NOW
MOST LIKELY IN THE SIERRA NEVADA. COMBINING ENERGIES WILL ALLOW
RAIN CHANCES TO STRETCH EAST INTO THE CENTRAL PLAINS AND MIDWEST
FOR MIDWEEK AND BEYOND. RAINFALL IS ALSO POSSIBLE ACROSS THE
NORTHEAST UNDERNEATH THE UPPER LOW.
WITH THE CLOSED UPPER LOW OVER THE WEST, TEMPERATURES SHOULD BE
BELOW NORMAL THROUGH ABOUT FRIDAY, WITH SOME MODERATING BACK
TOWARDS NORMAL AS THE TROUGH WEAKENS AND DRIFTS NEXT WEEKEND. THE
UPPER RIDGE TO ITS EAST WILL ALLOW FOR WARMER THAN AVERAGE
TEMPERATURES ACROSS THE NORTH- CENTRAL U.S. THROUGH MUCH OF NEXT
WEEK, WITH DAYTIME HIGHS 10-20 DEGREES ABOVE NORMAL, WITH GREATEST
ANOMALIES THROUGH AROUND MID TO LATE WEEK. RENEWED TROUGHING OVER
THE EAST MAY BRING SLIGHTLY BELOW NORMAL TEMPERATURES THERE AS
WELL.
OUDIT/SANTORELLI
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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