223
FXUS02 KWBC 110725
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
325 AM EDT SAT JUL 11 2026
VALID 12Z TUE JUL 14 2026 - 12Z SAT JUL 18 2026
...DANGEROUS HEAT CONTINUES ACROSS THE NORTH-CENTRAL U.S. THROUGH
NEXT WEEK...
..OVERVIEW
A BROAD AND ANOMALOUSLY STRONG UPPER-LEVEL RIDGE WILL BE IN PLACE
ACROSS THE INTERMOUNTAIN WEST TO NORTHERN PLAINS TO MIDWEST NEXT
WEEK, LEADING TO A SIGNIFICANT AND DANGEROUS HEAT WAVE CONTINUING
ACROSS THOSE REGIONS. RAIN AND THUNDERSTORMS ARE LIKELY ON THE
SOUTHERN PERIPHERY OF THE RIDGE, WITH ELEVATED CHANCES OF HEAVY
RAIN AND FLASH FLOODING IN WESTERN/CENTRAL TEXAS IN PARTICULAR.
ADDITIONALLY, MONSOONAL MOISTURE IS FORECAST TO INCREASE AND
PRODUCE SHOWERS AND STORMS ACROSS THE SOUTHWEST, FOUR CORNERS
STATES, AND NORTHWARD INTO THE NORTHERN ROCKIES/HIGH PLAINS. SOME
ENERGIES ON THE NORTHERN SIDE OF THE RIDGE COULD ALSO LEAD TO
ROUNDS OF RAIN AND THUNDERSTORMS IN THE NORTHERN TIER, INCLUDING A
NORTHERN NEW ENGLAND SEVERE THREAT TUESDAY.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE SHOWS GOOD AGREEMENT IN TERMS OF THE 594+ DM UPPER
HIGH CENTERED NEAR THE NORTH-CENTRAL U.S. AND MEANDERING NEXT WEEK,
LEADING TO HIGH CONFIDENCE IN MULTIPLE DAYS OF HAZARDOUS HEAT.
MODELS INDICATE THE RIDGE SHOULD STRETCH INTO PARTS OF THE
NORTHEAST TUESDAY BEFORE GETTING SUPPRESSED BY INTO THE MID-
ATLANTIC BY AN UPPER TROUGH MOVING IN BY THE LATTER HALF OF THE
WEEK. THE RIDGE AXIS THERE MAY JOIN WITH THE SUBTROPICAL ATLANTIC
HIGH THAT SHIFTS WEST THROUGH LATER NEXT WEEK; MEANWHILE FARTHER
WEST, THE RIDGE SHOULD GET RENEWED ACROSS THE NORTHERN/CENTRAL
ROCKIES AND PLAINS.
SMALLER-SCALE ENERGIES TO THE SOUTH OF THE RIDGE ARE RELATIVELY
MORE UNCERTAIN, BUT THERE IS AN INCREASING SIGNAL FOR LOWER HEIGHTS
WITH ENERGY ALOFT ACROSS THE SOUTHERN HIGH PLAINS MIDWEEK,
YIELDING INCREASING QPF. MEANWHILE A NORTHEASTERN PACIFIC UPPER LOW
HAS SHOWN THE MOST NOTABLE VARIATIONS IN THE GUIDANCE OVER THE
PAST DAY OR TWO. THE NEW 00Z MODEL CYCLE SHOWS THE CMC (AFTER A
FARTHER WEST 12Z RUN), ECMWF, AIFS, AND AI-GFS CLUSTERING AROUND A
MIDDLE GROUND TIMELINE OF MOVING INTO THE PACIFIC NORTHWEST AROUND
THURSDAY. THE 00Z GFS SPED UP COMPARED TO CONSENSUS AND ITS OLDER
RUNS, WHICH WAS LESS FAVORED. THE EVOLUTION OF THE LOW AS IT TRACKS
EAST AROUND THE NORTHERN PERIPHERY OF THE RIDGE LATE WEEK IS
SOMEWHAT QUESTIONABLE THOUGH.
THE WPC FORECAST WAS BASED ON A MULTI-MODEL DETERMINISTIC BLEND
EARLY ON, BUT REDUCED/ELIMINATED THE 00Z GFS FROM THE BLEND AND
OVERALL INCREASED THE PROPORTION OF THE ENSEMBLE MEANS AS THE
PERIOD PROGRESSED. THE MEANS REACHED HALF THE BLEND DAY 6 AND MORE
DAY 7, AMID INCREASING SPREAD PARTICULARLY FOR THE ENERGIES
NORTHWEST AND NORTH OF THE RIDGE.
..WEATHER/HAZARDS HIGHLIGHTS
A STRONG AND EXPANSIVE RIDGE SPRAWLING FROM THE WESTERN U.S. TO
THE CENTRAL U.S. WILL LEAD TO AN EXTENDED PERIOD OF DANGEROUS HEAT
FOR PARTS OF THE INTERMOUNTAIN WEST, NORTHERN PLAINS, AND UPPER
MIDWEST NEXT WEEK. SEVERAL DAYS OF WELL ABOVE NORMAL AND
POTENTIALLY RECORD-BREAKING MAXIMUM AND MINIMUM TEMPERATURES WILL
LEAD TO MAJOR TO EXTREME HEATRISK. WPC CONTINUES TO UPDATE HEAT KEY
MESSAGES FOR THIS EVENT, WHICH CAN BE FOUND ON OUR HOMEPAGE.
COVERAGE OF THE DANGEROUS HEAT COULD GRADUALLY BECOME MORE LIMITED
INTO LATE WEEK. FARTHER EAST, PERIODS OF WARMER THAN AVERAGE
TEMPERATURES ARE LIKELY FOR THE NORTHEAST PARTICULARLY ON TUESDAY,
SHIFTING INTO THE MID-ATLANTIC MIDWEEK AND BEYOND WHILE THE
NORTHEAST COOLS BEHIND A COLD FRONT. THE UPPER RIDGE POTENTIALLY
COMBINING WITH SUBTROPICAL RIDGING ACROSS FLORIDA WILL MAINTAIN
WARM TEMPERATURES AND ELEVATED HEATRISK THERE.
MEANWHILE, MUCH OF THE SOUTHERN TIER COULD SEE NEAR TO SLIGHTLY
BELOW AVERAGE TEMPERATURES AS A FRONT STALLS NEAR THE GULF COAST
AND ACTS AS A FOCUS FOR SHOWERS AND THUNDERSTORMS THROUGH AT LEAST
MIDWEEK. THE VERY MOIST AND UNSTABLE ENVIRONMENT COULD LEAD TO
FLASH FLOODING CONCERNS, AND BROAD MARGINAL RISKS OF FLASH FLOODING
ARE IN PLACE FOR DAYS 4-5 (TUESDAY-WEDNESDAY). EMBEDDED SLIGHT
RISKS ARE IN PLACE ACROSS PORTIONS OF TEXAS, WHERE PACIFIC AND GULF
MOISTURE SHOULD COMBINE IN THE VICINITY OF A SHORTWAVE ALOFT.
MEANWHILE, PREFRONTAL INSTABILITY AND MOISTURE WILL BE IN PLACE
ACROSS THE NORTHEAST ON TUESDAY, AND THE STORM PREDICTION CENTER
HAS DELINEATED A SEVERE THREAT IN NORTHERN NEW ENGLAND.
INCREASING SOUTHERLY FLOW AROUND THE WESTERN PERIPHERY OF THE
CENTRAL U.S. RIDGE WILL DRAW SIGNIFICANT MONSOONAL MOISTURE INTO
THE SOUTHWEST AND INTERMOUNTAIN WEST TO ROCKIES NEXT WEEK. THIS
MOISTURE WILL LEAD TO SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS WITH THE POTENTIAL TO PRODUCE HEAVY RAINFALL AND
LOCALIZED FLASH FLOODING. SENSITIVE PLACES SUCH AS BURN SCARS,
STEEP TERRAIN, ETC., WOULD BE THE MOST VULNERABLE TO ANY FLOODING
CONCERNS THAT MAY DEVELOP. BROAD MARGINAL RISKS OF EXCESSIVE
RAINFALL ARE DELINEATED FOR TUESDAY AND WEDNESDAY STRETCHING FROM
THE SOUTHWEST NORTH TO MONTANA. RAINFALL POTENTIAL SHOULD CONTINUE
FOR THAT REGION THROUGH LATE WEEK, WHILE POSSIBLE NORTHERN TIER
SHORTWAVES YIELD INCREASING RAIN CHANCES FOR THE GREAT LAKES AND
VICINITY.
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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