631
FXUS02 KWBC 080626
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
226 AM EDT SUN JUN 8 2025
VALID 12Z WED JUN 11 2025 - 12Z SUN JUN 15 2025
...HEAVY RAIN AND FLASH FLOOD THREAT FOR THE SOUTH-CENTRAL U.S.
NEXT WEEK...
..OVERVIEW
A FRONTAL BOUNDARY SETTLED ACROSS THE SOUTH EARLY TO MID WEEK
BEFORE EVENTUALLY LIFTING NORTHWARD WILL CONTINUE TO PROVIDE FOCUS
FOR MODERATE TO HEAVY RAINFALL ACROSS PORTIONS OF THE SOUTH AND
INTO THE MIDDLE MISSISSIPPI VALLEY. TO THE NORTH, A SHORTWAVE
MOVING THROUGH THE NORTHWEST THROUGH THE NORTHERN PLAINS WILL BRING
SHOWERS AND THUNDERSTORMS MID TO LATE NEXT WEEK. RAINFALL WILL
INCREASE IN COVERAGE ACROSS THE OHIO VALLEY INTO THE EAST NEXT
WEEKEND AHEAD OF SHORTWAVE ENERGY LIFTING INTO THE REGION FROM THE
SOUTHERN PLAINS.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST SUITE OF MODEL AND ENSEMBLE GUIDANCE ALL CONTINUE TO
SHOW ABOVE AVERAGE AGREEMENT ON THE OVERALL LARGE SCALE PATTERN AND
EVOLUTION DURING THE MEDIUM RANGE PERIOD, BUT STILL WITH PLENTY OF
UNCERTAINTY IN THE DETAILS WHICH WOULD IMPACT SENSIBLE WEATHER.
EARLY PERIOD ISSUES SURROUND WAVES OF ENERGY SLIDING THROUGH THE
NORTHEAST, BUT A GENERAL MODEL BLEND SEEMS TO PROVIDE A GOOD
STARTING POINT FOR DETAILS THAT WILL NEED UNTIL THE SHORT RANGE TO
RESOLVE. BEHIND THIS, THERE ARE DIFFERENCES IN THE TIMING AND
STRENGTH OF A SHORTWAVE LIFTING FROM THE SOUTHERN PLAINS INTO THE
OHIO VALLEY LATER IN THE WEEK, WHICH HAS BIGGER IMPLICATIONS ON QPF
COVERAGE AND AMOUNTS ACROSS THIS REGION. A SHORTWAVE INTO THE
NORTHWEST MID WEEK LOOKS GOOD FOR TIMING, BUT BIGGER ISSUES ARISE
NEXT WEEKEND WITH ENERGY AROUND AN UPPER LOW AS IT DROPS SOUTHWARD.
THIS AFFECTS ADDITIONAL SHORTWAVE TIMING INTO THE WEST. THE LATE
PERIOD BLEND FOR WPC LEANED SLIGHTLY MORE HEAVILY ON THE ENSEMBLE
MEANS TO HELP MITIGATE THESE DIFFERENCES.
..WEATHER/HAZARDS HIGHLIGHTS
A TRAILING FRONTAL BOUNDARY DRAPED GENERALLY WEST TO EAST ACROSS
THE SOUTH WILL CONTINUE TO PROVIDE FOCUS FOR NUMEROUS SHOWERS AND
THUNDERSTORMS THROUGH MOST OF NEXT WEEK. GUIDANCE CONTINUES TO
CONVERGE OF CENTRAL TEXAS INTO OKLAHOMA FOR MULTIPLE DAYS OF HEAVY
RAINFALL, WITH PARTS OF THIS AREA ALREADY PRIMED FROM RECENT
RAINFALL. ACCORDINGLY, THE DAYS 4 AND 5 EXCESSIVE RAINFALL OUTLOOKS
(VALID WEDNESDAY AND THURSDAY) SHOW SLIGHT RISK AREAS ACROSS THIS
REGION. INTENTIONALLY KEPT THE SLIGHT RISKS (AND SURROUNDING
MARGINAL RISKS) BROAD GIVEN SOME LINGERING UNCERTAINTIES IN EXACTLY
WHERE POSSIBLE CONVECTIVE COMPLEXES TRACK AND THE LOCATION OF
HEAVIEST RAIN. IF THE FORECAST MATERIALIZES THOUGH, IT IS POSSIBLE
A MODERATE RISK AREA MAY BE NEEDED AT SOME POINT IN THE FUTURE. BY
THURSDAY AND FRIDAY, THIS FRONT SHOULD LIFT NORTH PULLING THE
HEAVIER RAINS OUT OF TEXAS, BUT CONTINUING FOR PARTS OF OKLAHOMA
INTO THE MIDDLE MISSISSIPPI VALLEY, EVENTUALLY MOVING INTO THE OHIO
VALLEY AND EAST NEXT WEEKEND.
A SHORTWAVE INTERACTING WITH A FRONTAL BOUNDARY ACROSS THE
NORTHERN TIER WILL BRING SHOWERS AND STORMS ACROSS PARTS OF THE
NORTHERN ROCKIES INTO THE UPPER MIDWEST. MOISTURE ANOMALIES SHOULD
BE ABOVE THE 90TH PERCENTILE IN ESPECIALLY MONTANA, SUPPORTING A
MARGINAL RISK ON THE WEDNESDAY AND THURSDAY ERO. ADDITIONALLY,
CONVECTION IS LIKELY TO MOVE THROUGH THE NORTH- CENTRAL U.S. ALONG
THE CUSP OF THE INSTABILITY GRADIENT AND THUS THE MARGINAL RISK
ALSO EXTENDS EAST INTO THE UPPER MIDWEST.
A HEAT WAVE DURING THE SHORT RANGE PERIOD OVER THE WEST SHOULD
MODERATE BY THE START OF THE MEDIUM RANGE PERIOD, THOUGH ABOVE
NORMAL TEMPERATURES MAY CONTINUE ACROSS THE WEST THROUGH THE
PERIOD. DAYTIME HIGHS GENERALLY COULD BE 5 TO LOCALLY 15 DEGREES
ABOVE NORMAL. OTHERWISE, THE REST OF THE COUNTRY LOOKS NEAR NORMAL
OR WITHIN A FEW DEGREES OF NORMAL DEPENDING ON QUICK SYSTEMS MOVING
THROUGH.
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 (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
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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