053
FXUS02 KWBC 260718
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
318 AM EDT TUE MAY 26 2026
VALID 12Z FRI MAY 29 2026 - 12Z TUE JUN 02 2026
...HEAVY RAIN AND THUNDERSTORMS EXPECTED TO CONTINUE ACROSS MUCH
OF THE SOUTHERN U.S...
..OVERVIEW
SHORTWAVE ENERGY ACROSS THE SOUTHERN TO SOUTHEAST U.S. THROUGH
MOST OF THE PERIOD WILL CONTINUE TO BRING WIDESPREAD RAIN AND
THUNDERSTORMS WITHIN A MOIST AND UNSTABLE ENVIRONMENT. HEAVY RAIN
IS POSSIBLE, AND GIVEN HOW WET A LOT OF THIS REGION HAS BEEN LATELY
AND WILL BE IN THE SHORT RANGE AS WELL, FLOODING COULD BE A
CONCERN IN SOME PLACES. OUT WEST, A CLOSED UPPER LOW OVER THE
CENTRAL GREAT BASIN WHEN THE PERIOD BEGINS FRIDAY SHOULD LIFT
NORTHEASTWARD AND WEAKEN BY THE WEEKEND AS ANOTHER SHORTWAVE SLIDES
THROUGH THE PACIFIC NORTHWEST LATER IN THE PERIOD. THIS SHOULD
RESULT IN PRECIPITATION CHANCES FOR THE INTERMOUNTAIN WEST/NORTHERN
ROCKIES. REINFORCING TROUGHING OVER THE NORTHEAST SHOULD RESULT IN
NEAR TO BELOW NORMAL TEMPERATURES AND PRECIPITATION CHANCES.
MEANWHILE, IN BETWEEN, A BLOCKY RIDGE WILL BRING ABOVE NORMAL
TEMPERATURES TO MUCH OF THE NORTH-CENTRAL U.S. THROUGH THE PERIOD.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODELS SHOW GOOD AGREEMENT ON THE OVERALL LARGE SCALE PATTERN
EVOLUTION THROUGH THE PERIOD, BUT WITH SOME OF THE MORE TYPICAL
DIFFERENCES IN THE DETAILS, ESPECIALLY LATER IN THE PERIOD. SOME
INCREASING UNCERTAINTY BY EARLY NEXT WEEK ACROSS THE NORTHWEST
REGARDING THE EVOLUTION AS THE INITIAL UPPER LOW WEAKENS AND
ANOTHER SHORTWAVE MOVES INTO THE REGION. THERE IS QUESTION ON HOW
QUICKLY THIS PUSHES OUT OF THE REGION AND HOW STRONG RIDGING IS
ACROSS THE REGION BY NEXT TUESDAY. A LOT OF THIS SEEMS TO BE
RELATED TO A LARGE UPPER LOW ACROSS THE NORTHEAST PACIFIC AND THE
TIMING/LOCATION OF THAT. LOTS OF UNCERTAINTY IN THE NORTHEAST TOO
WITH VARIOUS WAVES OF ENERGY MOVING THROUGH THE GREAT LAKES TO
REINFORCE A MEAN TROUGH OVER MUCH OF THE EAST THROUGH THE PERIOD.
THIS ALSO IMPACTS THE STRUCTURE AND STRENGTH OF A STATIONARY RIDGE
OVER THE NORTH-CENTRAL U.S.. FOR THE MOST PART, A BLEND TOWARDS THE
ENSEMBLE MEANS SEEMED TO WORK OUT WELL FOR THE LATTER HALF OF THE
PERIOD TO MITIGATE THESE DIFFERENCES, WITH A GENERAL DETERMINISTIC
MODEL COMPROMISE WORKING FOR THE FIRST HALF WHERE MODEL CONSENSUS
IS BETTER.
..WEATHER/HAZARDS HIGHLIGHTS
PERSISTENT SOUTHERN STREAM ENERGY AND A COUPLE OF WEAK FRONTAL
BOUNDARIES 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. COMBINED WITH WHAT HAS
ALREADY BEEN A WET PATTERN ACROSS THIS REGION, FLOODING IS A
CONCERN. FOR DAY 4/FRIDAY, A BROAD MARGINAL RISK IS IN PLACE ON THE
ERO FROM THE LOWER/MIDDLE MISSISSIPPI VALLEY TO THE SOUTHEAST. FOR
SATURDAY, THE HEAVIEST RAIN SHOULD FOCUS ALONG A FRONTAL BOUNDARY
SINKING THROUGH THE SOUTHEAST, WHERE A MARGINAL RISK IS IN PLACE ON
THE ERO. MOISTURE AND PRECIPITATION LOOKS TO RENEW ACROSS TEXAS BY
THE WEEKEND AS WELL, AND A MARGINAL RISK WAS INTRODUCED FOR THAT
REGION ON DAY 5. FLORIDA WILL REMAIN WITHIN A WET PATTERN, AIDED BY
TROPICAL MOISTURE. MARGINAL RISKS ARE IN PLACE BOTH FRIDAY AND
SATURDAY FOR WHAT SHOULD BE MAINLY A URBAN FLASH FLOOD THREAT.
PRECIPITATION ACROSS THE SOUTH WILL CONTINUE INTO EARLY NEXT WEEK,
BUT SHOULD SHIFT SOUTHWARD WITH TIME AS THE TROUGH OVER THE EAST
DEEPENS, THOUGH CONTINUING ACROSS TEXAS AND THE SOUTHERN PLAINS.
UPPER TROUGHING MEANDERING AROUND THE GREAT BASIN WITH A FRONTAL
SYSTEM AHEAD OF IT WILL ALLOW FOR INCREASED PRECIPITATION ACROSS
THE INTERMOUNTAIN WEST FOR THE END OF THIS WEEK. SNOW IS POSSIBLE
ACROSS THE HIGHEST ELEVATIONS, THOUGH WITH MINIMAL ACCUMULATION. AS
THE UPPER LOW WEAKENS AND SHIFTS NORTHEAST, RAIN CHANCES SHOULD
INCREASE INTO THE CENTRAL HIGH PLAINS AND THE NORTHERN ROCKIES. IN
THE NORTHEAST, A VIGOROUS VORT MOVING THROUGH LATE THIS WEEK MAY
RESULT IN A PERIOD OF MODERATE TO HEAVY RAINFALL FOR PARTS OF NEW
ENGLAND.
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.
RIDGING BUILDING BACK INTO THE REGION LATE IN THE PERIOD MAY BRING
VALUES SLIGHTLY ABOVE AVERAGE. 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. PERSISTENT TROUGHING OVER THE EAST MAY BRING SLIGHTLY
BELOW NORMAL TEMPERATURES THROUGH THE PERIOD.
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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