701
FXUS02 KWBC 240751
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
351 AM EDT WED JUN 24 2026
VALID 12Z SAT JUN 27 2026 - 12Z WED JUL 01 2026
***ADDITIONAL HEAVY RAIN FOR THE MIDWEST AND OHIO VALLEY***
***HEAT AND HUMIDITY INCREASES ACROSS THE CENTRAL AND SOUTHERN
U.S. STARTING THIS WEEKEND***
..PATTERN OVERVIEW
A PATTERN CHANGE WILL BE EVOLVING BY THE BEGINNING OF THE FORECAST
PERIOD SATURDAY WITH AN ANOMALOUS UPPER LOW DROPPING SOUTHWARD
ACROSS THE NORTHWESTERN STATES. THIS WILL PUT AN END TO THE HEAT
WAVE ACROSS THE SOUTHWEST AND EVEN LEAD TO SOME HIGHER ELEVATION
SNOW FOR THE NORTHERN ROCKIES. THIS TROUGH WILL SPUR SURFACE
CYCLOGENESIS ACROSS THE PLAINS WITH AN OCCLUDED LOW LIFTING NORTH
ACROSS SOUTH-CENTRAL CANADA. IN RESPONSE TO THE INCOMING TROUGH
WILL BE A BUILDING DOWNSTREAM UPPER RIDGE ACROSS THE EAST-CENTRAL
U.S. THAT WILL RESULT IN INCREASING HEAT AND HUMIDITY GOING INTO
NEXT WEEK. NUMEROUS SHOWERS AND STORMS ARE LIKELY FROM THE OHIO
VALLEY TO THE NORTHEAST ON SATURDAY TO THE SOUTH OF A SLOW MOVING
FRONTAL BOUNDARY.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE 00Z MODEL GUIDANCE SUITE FEATURES GOOD OVERALL SYNOPTIC SCALE
AGREEMENT THROUGH THE WEEKEND, AND THE CMC HAS COME MORE IN LINE
WITH THE MODEL CONSENSUS COMPARED TO YESTERDAY WHEN IT HAD A TROUGH
CUTTING THE NORTHERN PORTION OF THE RIDGE AXIS ACROSS THE GREAT
LAKES REGION. HOWEVER, MODEL DIFFERENCES BECOME MORE PRONOUNCED
ACROSS THE WEST GOING INTO WEDNESDAY AS A POTENTIAL SECOND TROUGH
BUILDS INTO THE PACIFIC NORTHWEST.
THE WPC FRONTS/PRESSURES WERE BASED ON A GENERAL DETERMINISTIC
MODEL BLEND FOR THE WEEKEND, FOLLOWED BY GRADUALLY INCREASING
PERCENTAGE OF THE ENSEMBLE MEANS TOWARDS THE MIDDLE OF NEXT WEEK.
THE NBM WAS A REASONABLE STARTING POINT FOR MOST AREAS OF THE
COUNTRY, ALTHOUGH A SMOOTHER QPF FIELD WAS USED TO REPLACE SOME OF
THE HIGH QPF MAXIMA AND A REDUCTION OF 0.01 INCH AREAS WHERE IT WAS
WIDESPREAD. IN ADDITION, TEMPERATURES WERE LOWERED FOR COASTAL
AREAS OF THE MID-ATLANTIC, NORTHEAST, AND THE GREAT LAKES.
..WEATHER/HAZARDS HIGHLIGHTS
A STORMY START TO THE WEEKEND IS FORECAST ACROSS THE OHIO VALLEY
AND INTO THE CENTRAL APPALACHIANS AS A WAVE OF LOW PRESSURE AND A
SHORTWAVE ALOFT FUEL THE DEVELOPMENT OF WIDESPREAD SHOWERS AND
STORMS, WITH 1-2 INCH RAINFALL TOTALS LIKELY WHERE STORMS ARE MOST
PERSISTENT. ANOTHER REGION OF PERTURBED WEATHER WILL ALSO BE LIKELY
ACROSS THE DAKOTAS WITH ENHANCED RAINFALL AND STRONG/SEVERE
THUNDERSTORMS DEVELOPING NEAR THE MAIN SURFACE LOW. BOTH OF THESE
AREAS PROBABLY HAVE AN ABATEMENT IN RAINFALL COVERAGE AND INTENSITY
BY SUNDAY. LOOKING AHEAD TO MONDAY/TUESDAY, A CORRIDOR OF SHOWERS
AND STORMS, SOME OF WHICH COULD BE HEAVY, ARE FORECAST TO DEVELOP
FROM NEBRASKA TO THE UPPER PENINSULA OF MICHIGAN AHEAD OF THE COLD
FRONT CROSSING THE UPPER MIDWEST.
ELSEWHERE ACROSS THE COUNTRY, DECREASING SNOW LEVELS ACROSS THE
NORTHERN ROCKIES WILL LEAD TO A VERY LATE SEASON SNOWFALL ACROSS
THE HIGHER TERRAIN OF WESTERN MONTANA, CENTRAL IDAHO, AND
NORTHWESTERN WYOMING, ESPECIALLY SATURDAY NIGHT INTO EARLY SUNDAY,
AND COLD RAIN FOR THE VALLEYS. SOME THUNDERSTORMS MAY DEVELOP
ALONG THE DRYLINE ACROSS WESTERN TEXAS FOR THE BEGINNING OF THE
WEEK, BUT CURRENTLY NOT EXPECTED TO BE WIDESPREAD. SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED FROM THE CENTRAL GULF COAST
TO THE FLORIDA PENINSULA FOR THE FIRST HALF OF NEXT WEEK WITH
MOISTURE INCREASING SOUTH OF THE UPPER RIDGE.
A TEMPERATURE DICHOTOMY WILL EXIST ACROSS THE COUNTRY STARTING THIS
WEEKEND AS THE DEEP UPPER TROUGH HERALDS THE ARRIVAL OF MUCH COOLER
CONDITIONS STARTING ACROSS THE PACIFIC NORTHWEST, AND THEN THE
ROCKIES BY SUNDAY WITH HIGHS RUNNING ON THE ORDER OF 15-25 DEGREES
BELOW LATE JUNE AVERAGES. THIS WILL LIKELY BE COLD ENOUGH TO
ESTABLISH SOME NEW DAILY RECORD LOW TEMPERATURES. THE OPPOSITE WILL
HOLD TRUE FROM THE PLAINS TO THE OHIO VALLEY WITH WIDESPREAD ABOVE
AVERAGE TEMPERATURES EXPECTED WITH THE STRONG UPPER RIDGE
DEVELOPING. HIGHS IN THE 90S ARE EXPECTED AS FAR NORTH AS THE GREAT
LAKES AND MINNESOTA, AND 100S FOR MUCH OF TEXAS. HEAT INDICES
APPROACHING 110 DEGREES ARE POSSIBLE FROM THE MID-SOUTH TO THE
CENTRAL GULF COAST WHERE THE COMBINATION OF HEAT AND HIGH DEWPOINTS
WILL BE GREATEST. OVERNIGHT LOWS WILL ALSO BE QUITE WARM, WITH
SOME RECORD HIGH MINIMUMS POSSIBLE.
HAMRICK
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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