040
FXUS02 KWBC 212000
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 PM EDT TUE JUL 21 2026
VALID 12Z FRI JUL 24 2026 - 12Z TUE JUL 28 2026
..HEAVY RAINFALL/FLOODING THREAT FOR COASTAL SOUTHEAST U.S.
...HAZARDOUS HEAT TO PERSIST BROADLY ACROSS THE WESTERN AND CENTRAL
U.S. AS MONSOONAL RAINS PERSIST ACROSS THE FOUR CORNERS STATES...
..OVERVIEW
HOT AND HUMID CONDITIONS WILL LINGER OVER THE SOUTH-CENTRAL U.S.
THIS WEEK AS THE REMNANTS OF BERTHA SHOULD BE MOVING INTO NORTHERN
MEXICO. NORTHERN STREAM SHORTWAVES WORKING INTO AN UPPER TROUGH
AXIS OVER THE EAST AND A SLOWING TREND ON AN EXITING FRONTAL WAVE
WILL BRING FOCUS FOR ROUNDS OF LOCALLY HEAVY RAINS LATER THIS WEEK
TOWARD COASTAL NORTH CAROLINA. MEANWHILE, MONSOONAL MOISTURE NOW
STREAMING OVER THE SOUTHWEST AND INTERMOUNTAIN WEST/ROCKIES AND
AFFECTING THE CENTRAL U.S. DOWNSTREAM WILL FUEL ENHANCED SHOWERS
AND THUNDERSTORMS. HIGH HEAT/UPPER RIDGING WILL PEAK OVER THE
NORTHERN PLAINS THIS WEEKEND BUT WILL INTENSIFY OVER THE CENTRAL
PLAINS EARLY NEXT WEEK. THE CENTRAL U.S. UPPER RIDGE BUILDING INTO
THE WESTERN U.S. WILL SUPPORT HEAT IN THE INTERIOR U.S. BEFORE
EASING EARLY NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
LATEST GUIDANCE CONTINUES TO SHOW REASONABLY GOOD AGREEMENT AND
FORECAST CONFIDENCE ON THE LARGE SCALE PATTERN TO FEATURE A LARGE
WARMING UPPER RIDGE THAT BUILDS OVER THE INTERMOUNTAIN
WEST/SOUTHWEST/ROCKIES/PLAINS AS SANDWICHED BETWEEN AMPLIFIED UPPER
TROUGHS UPSTREAM JUST OFF THE WEST COAST AND DOWNSTREAM OVER THE
EAST. THE MAIN UNCERTAINTIES AND MODEL TRENDS ARE (1) A SLOWING
TREND ON THE FRONTAL WAVE MOVING OFF THE EAST COAST LATE THIS WEEK,
(2) LESS PROGRESSIVE ON THE QPF MAXIMUM OVER THE CENTRAL PLAINS
LATE THIS WEEK, AND (3) MORE PROGRESSIVE TROUGHING TO DIP INTO THE
GREAT LAKES AND THE NORTHEAST EARLY NEXT WEEK.
WPC FORECAST CONTINUITY APPEARS TO BE GOOD.
..WEATHER/HAZARDS HIGHLIGHTS
FLOW AROUND A MAIN UPPER RIDGE WILL CONTINUE TO DRAW SIGNIFICANT
MONSOONAL MOISTURE INTO THE SOUTHWEST AND INTERMOUNTAIN
WEST/ROCKIES THIS WEEK, WITH THE NEXT INFLUX OF MOISTURE FROM
MEXICO POSSIBLE EARLY NEXT WEEK. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE EXPECTED WITH HEAVY RAINFALL AND LOCALIZED FLASH
FLOODING POTENTIALS. SENSITIVE PLACES SUCH AS BURN SCARS, STEEP
TERRAIN, ETC., WOULD BE THE MOST VULNERABLE TO POSSIBLE FLOODING
CONCERNS. MARGINAL RISKS OF EXCESSIVE RAINFALL SPAN THE FOUR
CORNERS STATES FRIDAY INTO THE WEEKEND. A SLIGHT RISK AREA IS
MAINTAINED ACROSS MISSOURI ON FRIDAY WHERE CONVECTION MAY
FOCUS/TRAIN IN THE PRE-WARM-FRONTAL ENVIRONMENT.
UPPER RIDGE/CLOSED HIGH INFLUENCE OVER THE SOUTH-CENTRAL U.S.
OFFERS AT LEAST MAJOR HEATRISKS THIS WEEK AS TEMPERATURES UP TO
5-10F ABOVE SUMMER PEAK AVERAGES COMBINE WITH HIGH HUMIDITY.
EXPECT SPOTTY RECORD HIGHS AND MORE WIDESPREAD RECORD OVERNIGHT
LOWS TO LIMIT RELIEF. HEAT INDICES WILL SOAR UPWARDS TO 105-110+F
IN SOME SPOTS. THE HEAT IS FORECAST TO PEAK OVER THE NORTHERN
PLAINS THIS WEEKEND BUT WILL LIKELY INTENSIFY OVER THE CENTRAL
PLAINS EARLY NEXT WEEK. WESTWARD EXTENSION OF THE UPPER RIDGE WILL
EXPAND THE HEAT INTO THE INTERIOR WESTERN U.S. LATE THIS WEEKEND
INTO THE WEEKEND BEFORE POSSIBLY A SLOW MODERATING TREND SETS IN
EARLY NEXT WEEK.
ELSEWHERE, REPEATED CONVECTION-ENHANCED HEAVY RAINS ARE FORECAST
TO FOCUS OVER THE EASTERN CAROLINAS/SOUTHEAST LATER WEEK/WEEKEND
GIVEN SUPPORT ALOFT AND SLOWED FRONTAL PROGRESSION. WPC EXCESSIVE
RAINFALL MARGINAL RISKS FRIDAY AND SATURDAY INCLUDE AN EMBEDDED
SLIGHT RISK AREA IN EASTERN CAROLINAS. MEANWHILE, REMNANTS OF
TROPICAL STORM BERTHA SHOULD HAVE EXITED TEXAS AND BE MOVING INTO
NORTHERN MEXICO ON FRIDAY.
UPSTREAM, PERSISTENT UPPER TROUGHING AND EMBEDDED MOISTURE FEED
OFFERS MULTI-DAY MID-SUMMER LIGHT RAIN CHANCES TO CLIP THE PACIFIC
NORTHWEST THIS WEEKEND.
KONG/SCHICHTEL
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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