227
FXUS02 KWBC 130723
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
323 AM EDT MON JUL 13 2026
VALID 12Z THU JUL 16 2026 - 12Z MON JUL 20 2026
...DANGEROUS HEAT CONTINUES ACROSS THE NORTH-CENTRAL U.S. THROUGH
THE END OF THE WEEK...
..OVERVIEW
A STRONG UPPER RIDGE/HIGH OVER THE NORTH-CENTRAL U.S. WILL
CONTINUE TO CAUSE DANGEROUS HEAT ACROSS THE NORTHERN PLAINS AND
MIDWEST LATE WEEK. THE EASTERN PORTION OF THE RIDGE LIKELY JOINING
UP WITH A SUBTROPICAL ATLANTIC RIDGE SHOULD LEAD TO HOT
TEMPERATURES ACROSS THE OHIO VALLEY TO MID-ATLANTIC THURSDAY AND
GRADUALLY SHIFTING SOUTH THROUGH THE PERIOD AS AN UPPER TROUGH
POKES INTO THE NORTHEAST. ENERGY TO THE SOUTH OF THE RIDGE WILL
PROVIDE SUPPORT FOR ADDITIONAL HEAVY RAIN AND FLOODING POTENTIAL IN
PARTS OF TEXAS INTO THURSDAY. MONSOONAL MOISTURE IS FORECAST TO
INCREASE AND PRODUCE DIURNALLY DRIVEN SHOWERS AND STORMS ACROSS THE
SOUTHWEST, FOUR CORNERS STATES, AND NORTHWARD INTO THE NORTHERN
ROCKIES/HIGH PLAINS. ADDITIONALLY, ENERGIES ON THE NORTHERN SIDE OF
THE RIDGE COULD ALSO LEAD TO ROUNDS OF RAIN AND THUNDERSTORMS IN
THE GREAT LAKES TO EAST COAST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE SHOWS GOOD AGREEMENT IN TERMS OF THE 594+ DM UPPER
HIGH CENTERED NEAR THE NORTH-CENTRAL U.S. AT THE START OF THE
MEDIUM RANGE PERIOD THURSDAY, PROVIDING HIGH CONFIDENCE FOR
CONTINUED HEAT. ENERGY UNDERCUTTING THE RIDGE WILL BE IN PLACE OVER
THE SOUTHERN HIGH PLAINS, CONTINUING HEAVY RAIN INTO THURSDAY, BUT
SHOULD GRADUALLY WEAKEN LATE WEEK. MEANWHILE, MODEL CONSENSUS IS
INITIALLY GOOD FOR GREAT LAKES TO NORTHEAST TROUGHING.
INTO LATE WEEK/WEEKEND, MODELS DIVERGE WITH SOME DETAILS OF THE
PATTERN. IN GENERAL, THE NORTHEASTERN TROUGH IS FORECAST TO
GRADUALLY DEEPEN OVER THE WEEKEND AND EARLY NEXT WEEK, WHICH SHUNTS
THE UPPER RIDGE AXIS WESTWARD A BIT INTO THE INTERMOUNTAIN WEST.
HOWEVER, SHORTWAVES WITHIN THE TROUGH HAVE BEEN QUESTIONABLE,
AFFECTING THE TROUGH'S DEPTH AS WELL AS QPF AND FRONTAL PLACEMENT.
RECENT 00Z GUIDANCE MOSTLY SHOWS A DEEPER TROUGH COMPARED TO
EARLIER GUIDANCE, DUE TO A SHORTWAVE MOVING THROUGH THE GREAT LAKES
OVER THE WEEKEND. MEANWHILE, MODELS HAVE STRUGGLED WITH AN UPPER
LOW IN THE EASTERN PACIFIC OFFSHORE OF THE PACIFIC NORTHWEST. THE
12Z AIFS AND AIGFS HAD THE FEATURE MEANDERING THERE THROUGH MUCH OF
THE PERIOD BEFORE FINALLY MOVING INTO THE NORTHWEST EARLY NEXT
WEEK, WHILE DYNAMICAL MODELS WERE FASTER. HOWEVER, NOW WITH THE 00Z
CYCLE, THE GFS/CMC/UKMET ARE ALL MUCH SLOWER AND ALIGN WITH THOSE
AI MODELS. THE 00Z ECMWF IS GENERALLY ALONE IN TAKING THAT LOW
INLAND BY FRIDAY AND TRACKING IT ACROSS SOUTHERN CANADA. ELSEWHERE,
WILL ALSO NOTE THAT THE AIGFS/AIFS AND MANY AIFS MEMBERS ARE
FAVORING A TROPICAL LOW IN THE NORTHEASTERN GULF EARLY NEXT WEEK,
WHICH BEARS WATCHING.
THE WPC FORECAST WAS BASED ON A MODEL/ENSEMBLE MEAN BLEND
EXCLUDING THE ECMWF GIVEN ITS ISSUES WITH THE NORTHWEST LOW.
INCREASED PROPORTIONS OF THE MEANS AS THE FORECAST PROGRESSED,
REACHING HALF DAYS 6/7.
..WEATHER/HAZARDS HIGHLIGHTS
HAZARDOUS HEAT IS FORECAST TO PERSIST IN THE NORTH-CENTRAL U.S.
INTO LATE WEEK UNDER THE UPPER RIDGE. CONTINUED WELL ABOVE NORMAL
MAXIMUM AND MINIMUM TEMPERATURES WILL LEAD TO MAJOR TO EXTREME
HEATRISK IN THE NORTHERN/CENTRAL PLAINS AND MIDWEST. WPC CONTINUES
TO UPDATE HEAT KEY MESSAGES FOR THIS EVENT, WHICH CAN BE FOUND ON
OUR HOMEPAGE. THE HOT CONDITIONS SHOULD SLOWLY EASE IN THE NORTHERN
STATES AND SHIFT SOUTHWARD INTO EARLY NEXT WEEK. FARTHER EAST,
WARMER THAN AVERAGE TEMPERATURES ARE LIKELY FOR THE MID-ATLANTIC
THURSDAY, SHIFTING GRADUALLY SOUTHWARD AS AN UPPER TROUGH PUSHES A
COLD FRONT SLOWLY SOUTH. THE UPPER RIDGE POTENTIALLY COMBINING WITH
SUBTROPICAL RIDGING DOWN TO FLORIDA WILL MAINTAIN WARM
TEMPERATURES AND ELEVATED HEATRISK THERE.
MEANWHILE, THE SOUTHWESTERN TO SOUTH-CENTRAL U.S. COULD SEE
SLIGHTLY BELOW AVERAGE TEMPERATURES AS AMPLE MOISTURE LEADS TO
CLOUDS AND RAIN/THUNDERSTORMS. 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. THIS MOISTURE WILL LEAD TO DIURNALLY DRIVEN 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 REMAIN IN PLACE FROM THE SOUTHWEST ACROSS PARTS
OF THE INTERMOUNTAIN WEST NORTH TO MONTANA FOR DAY 4-5 (THURSDAY-
FRIDAY), AND MONSOONAL MOISTURE SHOULD CONTINUE INTO NEXT WEEKEND.
FARTHER EAST, PACIFIC AND GULF MOISTURE SHOULD COMBINE IN THE
VICINITY OF A SHORTWAVE ALOFT OVER TEXAS, LEADING TO FURTHER
FLOODING CONCERNS. A SLIGHT RISK IS IN PLACE FOR WESTERN/SOUTH-
CENTRAL PORTIONS OF TEXAS INTO THURSDAY, AND THE FLOODING THREAT
COULD BE COMPOUNDED BY THE LIKELY RAINFALL IN THE SHORT RANGE
PERIOD CAUSING WETTER ANTECEDENT CONDITIONS. THE ENERGY ALOFT
SHOULD GRADUALLY DISSIPATE INTO FRIDAY AND SLOWLY EASE THE FLOODING
THREAT. SOME SHOWERS AND STORMS SHOULD STRETCH INTO THE SOUTHEAST.
AS ENERGY MOVES THROUGH THE NORTHEASTERN UPPER TROUGH, ROUNDS OF
RAIN/THUNDERSTORMS ARE ALSO POSSIBLE FROM THE GREAT LAKES TO THE
MID-ATLANTIC AND NORTHEAST, INCLUDING POTENTIALLY SEVERE WEATHER.
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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