093
FXUS02 KWBC 220647
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
247 AM EDT FRI MAY 22 2026
VALID 12Z MON MAY 25 2026 - 12Z FRI MAY 29 2026
...HEAVY RAIN AND THUNDERSTORMS EXPECTED TO CONTINUE ACROSS MUCH
OF THE SOUTHERN U.S...
..OVERVIEW
A COUPLE OF SOUTHERN STREAM UPPER TROUGHS WILL PASS THROUGH THE
SOUTHWESTERN AND SOUTH-CENTRAL U.S. NEXT WEEK, PROVIDING LIFT FOR
WIDESPREAD RAIN AND THUNDERSTORMS IN A MOIST AND UNSTABLE
ENVIRONMENT. THE HEAVIEST RAIN SHOULD GENERALLY AFFECT THE LOWER
MISSISSIPPI VALLEY AND SOUTHEAST INTO MONDAY, AND POTENTIALLY GET
RENEWED IN TEXAS AND VICINITY INTO THE WORKWEEK OVER AREAS THAT
WILL ALREADY HAVE WET ANTECEDENT CONDITIONS. A SHORTWAVE OVER THE
GREAT LAKES SHOULD REACH NORTHERN NEW ENGLAND BY MONDAY NIGHT, WITH
WIDESPREAD SHOWERS FROM THE OHIO VALLEY TO THE NORTHEAST AHEAD OF
THIS FEATURE. OUT WEST, A MORE AMPLIFIED PATTERN STARTS TO EMERGE
AS A STRONGER UPPER TROUGH LIKELY BECOMING A CLOSED LOW ENTERS THE
PACIFIC NORTHWEST AND ENVELOPS MORE OF THE INTERMOUNTAIN WEST BY
THE MIDDLE OF THE WEEK, YIELDING COOLER TEMPERATURES AND
PRECIPITATION. AN UPPER RIDGE SHOULD DEVELOP DOWNSTREAM IN THE
EAST-CENTRAL U.S., REACHING INTO THE UPPER MIDWEST/GREAT LAKES AND
BRINGING ABOVE AVERAGE TEMPERATURES.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST MODELS AND GUIDANCE SHOW GOOD AGREEMENT ON THE OVERALL
PATTERN EVOLUTION THROUGH THE PERIOD, WHICH SHOULD GRADUALLY TREND
MORE AND MORE AMPLIFIED THROUGH NEXT WEEK. THERE WAS GOOD ENOUGH
AGREEMENT BOTH WITH THE NORTHEAST SHORTWAVE AND A SERIES OF
SHORTWAVES ACROSS THE SOUTH FOR A GENERAL MODEL BLEND TO SERVE AS
THE STARTING POINT FOR THE WPC PROG CHARTS.
THE MAIN (AND MOST IMPACTFUL) SOURCE OF UNCERTAINTY CONTINUES TO
BE WITH AN UPPER LOW THAT ENTERS THE PACIFIC NORTHWEST AROUND
TUESDAY, DEEPENS/SHIFTS SOUTH THROUGH THURSDAY, THEN SHOULD START
TO SHIFT EASTWARD. THE BETTER CONSENSUS OF GUIDANCE (SUPPORTED BY
THE ECMWF, EC-AIFS, CMC, AND ECENS MEAN) SUGGESTS THIS GENERAL
PATTERN, AND THE LATEST 00Z RUN OF THE GFS TONIGHT HAS TRENDED
TOWARDS THIS AS WELL. THE WPC PROGS/SENSIBLE WEATHER GRIDS LEANS
HEAVIER ON THESE DEEPER/SLOWER SOLUTIONS, CONSISTENT WITH
CONTINUITY. A GENERAL TREND NOW TOWARDS THIS SEEMS TO INCREASE
CONFIDENCE A BIT.
..WEATHER/HAZARDS HIGHLIGHTS
THE NORTHERN STREAM TROUGH OVER THE NORTHEAST WILL ALLOW FOR
SCATTERED SHOWERS ALONG A FRONTAL BOUNDARY FROM THE LOWER OHIO
VALLEY INTO THE MID- ATLANTIC AND NORTHEAST ON MONDAY. CONVECTION
ALSO LOOKS TO SPARK IN THE FOUR CORNERS REGION ON MONDAY IN
RESPONSE TO A SOUTHERN STREAM SHORTWAVE. THIS SYSTEM LOOKS TO RENEW
HEAVY RAIN POTENTIAL IN TEXAS AND VICINITY AND THROUGH MUCH OF THE
SOUTHERN U.S./SOUTHEAST THROUGH NEXT WEEK. FOR NOW, JUST BROAD
MARGINAL RISKS ON THE DAY 4/MONDAY AND DAY 5/TUESDAY EROS SHOULD
SUFFICE, BUT IT'S POSSIBLE A SLIGHT RISK MAY BE NEEDED AS MODELS
CONVERGE ON BETTER POTENTIAL FOR WHERE HEAVY RAINFALL MAY OCCUR.
THIS IS ESPECIALLY TRUE FOR PARTS OF TEXAS AND VICINITY (TUESDAY
AND BEYOND) WHERE RECENT RAINS AND SHORT TERM RAINFALL HAS LEAD TO
RATHER SATURATED GROUNDS.
UPPER TROUGHING MOVING INTO THE NORTHWEST EARLY NEXT WEEK AND A
FRONTAL SYSTEM AHEAD OF IT WILL ALLOW FOR INCREASED PRECIPITATION
REACHING THE PACIFIC NORTHWEST AND SPREADING SOUTH AND EASTWARD
WITH TIME THROUGH THE WEEK. SNOW IS POSSIBLE AT THE HIGHEST
ELEVATIONS OF THE CASCADES TO ROCKIES.
WITH A DEEPENING TROUGH OVER THE WEST, TEMPERATURES SHOULD TREND
COOLER IN THIS REGION THROUGH ABOUT WEDNESDAY, WITH SOME MODERATING
BACK TOWARDS NORMAL AS THE TROUGH STARTS TO PRESS EASTWARD. 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, ESPECIALLY FOR
THE EARLY PART OF THE WEEK.
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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