543
FXUS02 KWBC 100714
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
314 AM EDT WED JUN 10 2026
VALID 12Z SAT JUN 13 2026 - 12Z WED JUN 17 2026
...HEAT BUILDING ACROSS THE WEST THIS WEEKEND INTO EARLY NEXT
WEEK...
...HEAVY RAINFALL THREAT IN SOUTHERN/CENTRAL PARTS OF THE PLAINS
AND MISSISSIPPI VALLEY EXPANDING INTO THE SOUTHEAST...
..OVERVIEW
A BROAD UPPER TROUGH WITH EMBEDDED SHORTWAVES WILL BE PRESENT
ACROSS THE NORTHERN TIER OF THE U.S. AS THE MEDIUM RANGE PERIOD
BEGINS SATURDAY, WHILE SUBTROPICAL RIDGING SETS UP OVER THE
SOUTHERN TIER AND BRINGS HOT TEMPERATURES/HEAT INDICES THERE. A
FRONTAL BOUNDARY AHEAD OF THE TROUGH IS FORECAST TO MEANDER ACROSS
THE SOUTH-CENTRAL U.S. AND FOCUS MOISTURE FOR RAIN AND
THUNDERSTORMS. HEAVY RAINFALL IS POSSIBLE WITH MULTIPLE ROUNDS OF
STORMS EXPECTED TO SET UP IN THE SOUTHERN/CENTRAL PLAINS AND
LOWER/MID-MISSISSIPPI VALLEY OVER THE WEEKEND. A SHORTWAVE DIGGING
ON THE WESTERN SIDE OF THE UPPER TROUGH WILL SERVE TO DEEPEN IT AS
THE WORKWEEK PROGRESSES, WHICH SHOULD PUSH THE FRONT EAST AND BRING
HEAVY RAIN TO THE SOUTHEAST. UPSTREAM, UPPER RIDGING IS FORECAST
TO BUILD ACROSS THE WEST COAST, LEADING TO HOT TEMPERATURES THAT
WILL BE WELL ABOVE AVERAGE IN THE PACIFIC NORTHWEST EARLY NEXT
WEEK, WITH SOME UNCERTAINTY IN HOW LONG THE HEAT WILL LAST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE IS REASONABLY AGREEABLE IN THE OVERARCHING PATTERN
DESCRIBED ABOVE, THOUGH THERE ARE DIFFERENCES IN THE DETAILS THAT
IMPACT SENSIBLE WEATHER, LIKE FRONTAL TIMING FOR TEMPERATURE AND
QPF DIFFERENCES. FIRST, THE EASTERN PART OF THE NORTHERN TROUGH
(ANCHORED BY AN UPPER LOW JUST SOUTH OF HUDSON BAY) HAS SHOWN
TIMING DIFFERENCES AS IT PROGRESSES FROM THE MIDWEST TO NORTHEAST
THIS WEEKEND INTO EARLY NEXT WEEK. THE NEW 00Z MODEL CYCLE IS
GENERALLY MORE AGREEABLE THAN THE 12/18Z CYCLE THOUGH, AFTER SOME
OF THE SLOWER MODELS LIKE THE 12Z ECMWF HAVE TRENDED FASTER AT 00Z.
UPSTREAM, A POTENT SHORTWAVE ATOP THE NORTHERN ROCKIES AND
VICINITY THIS WEEKEND SHOWS REASONABLE CONSENSUS TO DIG
SOUTHEASTWARD AND DEEPEN THE CENTRAL U.S. TROUGH. MOST 00Z GUIDANCE
HAS SHIFTED EAST WITH THE TROUGH POSITION, THOUGH THE GFS AND AI-
GFS ARE ON THE WESTERN SIDE OF THE MODEL SPREAD WITH MORE DIGGING.
MEANWHILE THERE IS GOOD AGREEMENT UPSTREAM FOR UPPER RIDGING ATOP
THE WEST, THOUGH SHORTWAVE ENERGY COULD REACH THE NORTHWEST TUESDAY
OR SO, WITH SOMEWHAT UNCERTAIN TIMING.
THE WPC FORECAST WAS BASED ON A MULTI-MODEL BLEND EARLY IN THE
PERIOD, WITH INCREASING PROPORTIONS OF ENSEMBLE MEANS AS THE PERIOD
PROGRESSED. MEANS COMPRISED HALF THE BLEND FOR FRONTS/PRESSURES BY
DAY 7 AMID INCREASING SPREAD.
..WEATHER/HAZARDS HIGHLIGHTS
LOW PRESSURE/FRONTAL SYSTEMS CONVERGING IN THE CENTRAL U.S. WILL
PROVIDE A FOCUS FOR THUNDERSTORMS THIS WEEKEND. AMPLE MOISTURE AND
INSTABILITY WILL MEAN SEVERE AND FLASH FLOODING THREATS ARE BOTH
POSSIBLE FOR PARTS OF THE CENTRAL PLAINS AND MIDDLE MISSISSIPPI
VALLEY ON SATURDAY, AND SHIFTED SOMEWHAT SOUTH INTO THE SOUTHERN
PLAINS/LOWER MISSISSIPPI VALLEY ON SUNDAY AS THE FRONTS MOVE SOUTH.
SLIGHT RISKS ARE PRESENT IN BOTH THE DAY 4/SATURDAY AND 5/SUNDAY
EROS--SEE THE NEW DAY 4-5 ERO DISCUSSION FOR MORE. AS THE FRONT
CONTINUES TO PRESS SLOWLY SOUTHEAST, AREAS OF HEAVY RAIN ARE
POSSIBLE IN THE TENNESSEE VALLEY TO SOUTHEAST WESTWARD INTO THE
LOWER MISSISSIPPI VALLEY TO TEXAS ON MONDAY AND TUESDAY. RAIN AND
THUNDERSTORMS ARE ALSO POSSIBLE THROUGH THE GREAT LAKES/OHIO VALLEY
TO APPALACHIANS AND EASTERN SEABOARD AT TIMES ALONG THE NORTHERN
PARTS OF THE FRONTS, THOUGH WITH UNCERTAINTY IN THE DETAILS.
ELSEWHERE, THE NORTHERN ROCKIES/HIGH PLAINS SHOULD SEE A ROUND OF
PRECIPITATION THIS WEEKEND AS THE SHORTWAVE ALOFT MOVES THROUGH,
WITH SOME SNOW POSSIBLE IN HIGHER ELEVATIONS. WEST OF THE ROCKIES
SHOULD REMAIN DRY UNDER THE UPPER RIDGING.
HOT AND HUMID CONDITIONS WILL BE PRESENT ACROSS THE SOUTHERN
PLAINS TO SOUTHEAST OVER THE WEEKEND UNDER THE SUBTROPICAL UPPER
RIDGE. THE EASTERN SEABOARD CAN EXPECT GENERALLY ABOVE NORMAL
TEMPERATURES, BUT MODERATED FROM THE HEAT IN THE SHORT RANGE
PERIOD. COOLER THAN AVERAGE TEMPERATURES ARE LIKELY UNDERNEATH THE
UPPER TROUGH IN THE NORTH-CENTRAL U.S., SPREADING INTO THE SOUTH
AND EAST AS THE WEEK PROGRESSES WHILE MODERATING. MEANWHILE, THE
WEST WILL BE WARMING UP. THE DESERT SOUTHWEST CAN EXPECT
TEMPERATURES WELL INTO THE 100S AND PERHAPS OVER 110 OVER THE
WEEKEND, WITH WARMER THAN AVERAGE TEMPERATURES EXTENDING INTO THE
CENTRAL GREAT BASIN. ABOVE AVERAGE TEMPERATURES WILL CONTINUE TO
SPREAD NORTHWARD INTO THE PACIFIC NORTHWEST OVER THE WEEKEND AND
EARLY NEXT WEEK. DAILY RECORD HIGHS COULD BE BROKEN AS TEMPERATURES
REACH THE 90S IN THE WILLAMETTE VALLEY AND 80S FARTHER NORTH
TOWARD SEATTLE. MODERATE TO SCATTERED MAJOR HEATRISK IS FORECAST
FOR MUCH OF THE WEST.
TATE
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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