477
FXUS02 KWBC 250713
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
313 AM 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
MODELS CONTINUE TO SHOW GOOD AGREEMENT ON THE OVERALL LARGE SCALE
PATTERN EVOLUTION THROUGH THE PERIOD, BUT WITH FAIRLY TYPICAL
DIFFERENCES IN THE DETAILS, WHICH AFFECT SENSIBLE WEATHER. GOOD
AGREEMENT CONTINUES WITH THE UPPER LOW INITIALLY CENTERED OVER THE
CENTRAL GREAT BASIN, WHICH SHOULD GRADUALLY WEAKEN INTO THE WEEKEND
WHILE JOINING WITH A NORTHEASTERN PACIFIC TROUGH. DOWNSTREAM,
UPPER RIDGING STRETCHES FROM THE SOUTHEAST INTO THE NORTH-CENTRAL
U.S., WITH SOUTHERN STREAM ENERGY UNDERCUTTING IT ACROSS THE SOUTH-
CENTRAL U.S.. EVENTUALLY, THIS RIDGE SHOULD REFORM WITH A MORE
NEUTRAL TILE AND AN OMEGA BLOCK TYPE OF LOOK WITH REINFORCED
TROUGHING OVER THE NORTHEAST. THIS TROUGHING OVER THE NORTHEAST
DOES CONTINUE TO SHOW SOME UNCERTAINTY, BUT THE NEW 00Z GUIDANCE
HAVE TRENDED MORE IN LINE WITH EACH OTHER ESPECIALLY AS IT PERTAINS
TO THE SPEED OF A COMPACT UPPER LOW SINGING THROUGH THE NORTHEAST
THIS WEEKEND.
THE WPC FORECAST WAS BASED ON A BLEND OF THE ECMWF, EC-AIFS, AND
GFS (WITH MINOR ECENS) THROUGH DAY 5. AFTER THIS, INCREASED THE
WEIGHTING OF THE ENSEMBLE MEANS TO HELP MITIGATE SOME OF THE
SMALLER SCALE DETAILS DIFFERENCES.
..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
AND INSTABILITY WILL NOT BE LACKING. THERE REMAINS A LOT OF MODEL
UNCERTAINTY STILL ON WHERE THE HEAVIEST QPF MAY FOCUS, SO HELD OFF
ON ANY SLIGHT RISKS FOR NOW BUT IT'S POSSIBLE A SLIGHT RISK MAY BE
NEEDED EVENTUALLY. 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.
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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