980
FXUS02 KWBC 180800
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 AM EDT THU JUN 18 2026
VALID 12Z SUN JUN 21 2026 - 12Z THU JUN 25 2026
...HEAVY RAINFALL/FLOODING AND SEVERE WEATHER THREAT FROM THE
MIDWEST TO PORTIONS OF THE NORTHEAST THIS WEEKEND INTO MONDAY...
..PATTERN OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
THE MAIN CONCERN ON THE SYNOPTIC PATTERN EVOLUTION DURING THE
MEDIUM-RANGE FORECAST PERIOD REMAINS ACROSS THE CENTRAL TO NORTHERN
TIER STATES WHERE MODEL CONSENSUS HAS GRADUALLY TRENDED TOWARD A
FASTER EASTWARD EJECTION AND MORE ROBUST AMPLIFICATION OF A WAVE
TOWARD THE NORTHEAST, LEADING TO A TENDENCY FOR MORE HIGH PRESSURE
TO BUILD SOUTHWARD ACROSS THE GREAT LAKES INTO THE EAST-CENTRAL
U.S. BEHIND THE WAVE. THE HEAVY RAIN SIGNAL AHEAD OF THIS WAVE HAS
SHIFTED FARTHER NORTH ACROSS THE MIDWEST AND THE LOWER GREAT LAKES
THIS WEEKEND, AND SPREADING FARTHER EAST TOWARD INTERIOR NEW
ENGLAND BY MONDAY. THIS TREND HAS ALSO SHIFTED THE QPF AXIS
FARTHER SOUTHWEST INTO THE SOUTH-CENTRAL U.S. AND ACROSS THE DEEP
SOUTH BY MIDWEEK NEXT WEEK. THE 00Z ECMWF APPEARS TO FURTHER
SUPPORT THIS GENERAL MODEL TREND.
OTHERWISE, BROAD UPPER TROUGHING REMAINS DOMINANT ACROSS THE
EASTERN TWO-THIRDS OF THE COUNTRY INTO MIDWEEK NEXT WEEK. IN
CONTRAST, THERE IS GENERAL MODEL CONSENSUS FOR THE UPPER RIDGE
OVER THE WEST TO BUILD NEXT WEEK, LEADING TO INCREASINGLY ABOVE
AVERAGE TEMPERATURES, ESPECIALLY FOR THE PACIFIC NORTHWEST.
A GENERAL MODEL BLEND OF THE 12Z ECMWF/EC MEAN, 18Z GFS/GEFS MEAN,
AND THE 12Z CMC/CMC MEAN WERE USED TO COMPOSE THE WPC FORECASTS,
WITH THE USUAL GRADUAL INCREASE IN ENSEMBLE MEAN WEIGHTING FOR
DAYS 6 AND 7. THE SLOW CMC SOLUTION IS AVOIDED BY DAY 5.
..WEATHER/HAZARDS HIGHLIGHTS
GIVEN THE ABOVE-MENTIONED MODEL TRENDS, THE MARGINAL AND SLIGHT
RISKS OF EXCESSIVE RAINFALL OUTLOOK ARE ADJUSTED FARTHER NORTH
ACROSS THE MIDWEST AND LOWER GREAT LAKES. SOME STRONG TO SEVERE
THUNDERSTORMS CAN ALSO BE EXPECTED AHEAD OF THE AMPLIFYING WAVE
FORECAST TO TRACK ACROSS THESE AREAS. THE SYSTEM SHOULD CLEAR THE
NORTHEAST AND THE MID-ATLANTIC BY TUESDAY BUT THE TRAILING FRONT IS
FORECAST TO BECOME STATIONARY ACROSS THE SOUTHEAST, DEEP SOUTH AND
INTO THE SOUTHERN PLAINS. THERE IS GOOD MODEL CONSENSUS FOR
MOISTURE TO LINGER ACROSS THE DEEP SOUTH TO THE SOUTHERN PLAINS
WHERE MODERATE TO LOCALLY HEAVY RAIN APPEARS TO CONTINUE FROM EARLY
TO MIDDLE OF NEXT WEEK. A MARGINAL RISK HAS BEEN INTRODUCE TO COVER
THE SOUTHERN PLAINS THROUGH THE MID-ATLANTIC AND SOUTHERN NEW
ENGLAND FOR DAY 5 IN EXCESSIVE RAINFALL OUTLOOK. BY NEXT THURSDAY,
THERE IS A GOOD MODEL SIGNAL FOR CONVECTIVE RAINFALL TO ORGANIZE
AND EXPAND ACROSS THE CENTRAL TO NORTHERN PLAINS AHEAD OF THE NEXT
UPPER- LEVEL DISTURBANCE FORECAST TO EJECT OUT OF THE ROCKIES.
GENERALLY BELOW NORMAL TEMPERATURES APPEAR LIKELY FOR MUCH OF THE
EASTERN TWO-THIRDS OF THE COUNTRY THROUGH THE MEDIUM-RANGE PERIOD.
HEAT AND HUMIDITY WILL BE CONFINED TO TEXAS, NEAR THE GULF COAST,
FLORIDA, AND PORTIONS OF THE MID-ATLANTIC. MEANWHILE, ABOVE NORMAL
TEMPERATURES WILL PREVAIL ACROSS THE WESTERN U.S. WITH HIGHS
GRADUALLY CLIMBING FURTHER INTO THE 110S IN THE DESERT SOUTHWEST.
HIGHS INTO THE 90S ARE FORECAST TO RETURN ACROSS THE PACIFIC
NORTHWEST EARLY NEXT WEEK BEFORE COOLING OFF BY MIDWEEK.
KONG
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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