660
FXUS02 KWBC 201828
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
228 PM EDT MON JUL 20 2026
VALID 12Z THU JUL 23 2026 - 12Z MON JUL 27 2026
... HEAVY RAINFALL THREAT FOCUS FOR THE EASTERN CAROLINAS AND FOR
CENTRAL TO WESTERN GULF COAST AREAS WITH TROPICAL SYSTEM "TWO"...
...HAZARDOUS HEAT OVER THE SOUTH-CENTRAL U.S. THIS WEEK TO SHIFT
TO THE WEST-CENTRAL AND NORTHERN U.S. INTO NEXT WEEK AS ONGOING
MONSOONAL RAINS OVER THE SOUTHWEST/INTERMOUNTAIN WEST/ROCKIES TEND
TO EASE...
..OVERVIEW
HOT AND MOIST CONDITIONS WILL LINGER OVER THE SOUTH-CENTRAL U.S.
THIS WEEK OUTSIDE THE INFLUENCE OF TROPICAL DEPRESSION TWO.
MEANWHILE, NORTHERN TIER SHORTWAVES WORKING INTO AN UPPER TROUGH
POSITION OVER THE EAST AND MODERATING SURFACE FRONTS WILL BRING
ROUNDS OF LOCALLY HEAVY RAINS LATER THIS WEEK DOWN OVER THE EASTERN
CAROLINAS WITH A SLOW MOVING AND MOISTURE POOLING FRONT. ACTIVITY
TO WORK WESTWARD OVER THE GULF COAST AND INTO TEXAS WILL BE FUELED
BY TROPICAL SYSTEM "TWO" DEVELOPMENT, TRACK AND DEEP MOISTURE.
ELSEWHERE, AMPLE MONSOONAL MOISTURE NOW STREAMING FROM THE
SOUTHWEST AND INTERMOUNTAIN WEST/ROCKIES INTO THE PLAINS WILL FUEL
ENHANCED SHOWERS AND THUNDERSTORMS. HEAT AND UPPER RIDGING OVER THE
SOUTHERN PLAINS WILL SHIFT NORTHWARD OVER THE PLAINS AND TO THE
SOUTHWEST/ROCKIES. MONSOONAL FLOW MAY EASE LATER IN THIS PERIOD
WITH THIS TRANSITION.
..GUIDANCE/PREDICTABILITY ASSESSMENT
LATEST GUIDANCE CONTINUES TO SHOW GOOD AGREEMENT ON THE LARGE
SCALE PATTERN THROUGH THE ENTIRE PERIOD FEATURING A LARGE UPPER
RIDGE THAT BUILDS OVER THE INTERMOUNTAIN WEST/CENTRAL U.S. IN
RESPONSE TO A RELOADING EASTERN RIDGE. THERE ARE SOME UNCERTAINTIES
ON THE INDIVIDUAL SHORTWAVES AS THEY DROP INTO THE TROUGH, AND ANY
SENSIBLE WEATHER/QPF IMPACTS ASSOCIATED WITH THEM. STILL A LOT OF
UNCERTAINTY ASSOCIATED WITH TD TWO, WHICH IS FORECAST BY THE NHC TO
STRENGTHEN INTO A TROPICAL STORM BEFORE THE MEDIUM RANGE PERIOD.
THERE IS QUESTION ON HOW MUCH OF A REFLECTION IS LEFT AFTER IT
CROSSES FAR SOUTHERN LOUISIANA DURING THE SHORT RANGE, AND HOW MUCH
MOISTURE MAY REACH THE COAST. MANY OF THE MODELS KEEP HEAVY
RAINFALL OFF THE COAST, BUT DID EDIT THE MANUAL WPC GRIDS TO BRING
SOME RAINFALL TOWARDS CENTRAL AND WESTERN GULF, CONSISTENT WITH
CONTINUITY.
THE WPC 500S/FRONTS WERE BASED ON A BLEND OF THE DETERMINISTIC
GUIDANCE THROUGH DAY 5, INCREASING TO 40 PERCENT OF THE ENSEMBLE
MEANS WITH 60 PERCENT DETERMINISTIC BY DAY 6 AND 7.
..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, BUT MAY EASE THIS WEEKEND/EARLY NEXT WEEK.
MOISTURE WILL FUEL SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
WITH POTENTIAL TO PRODUCE HEAVY RAINFALL AND LOCALIZED FLASH
FLOODING. 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 SOUTHWEST AND
INTERMOUNTAIN WEST/ROCKIES TO THE CENTRAL PLAINS/MID-MISSISSIPPI
VALLEY THURSDAY AND FRIDAY, WITH SMALL EMBEDDED SLIGHT RISK AREAS
FOR THE CENTRAL PLAINS/MID-MISSISSIPPI VALLEY WHERE CONVECTION MAY
FOCUS.
UPPER RIDGE/CLOSED HIGH INFLUENCE OVER THE SOUTH-CENTRAL U.S.
OFFERS MAJOR HEATRISKS THIS WEEK AS TEMPERATURES UPWARDS TO 5-10F
ABOVE ALREADY HOT AVERAGES COMBINE WITH HIGH HUMIDITY. EXPECT
SPOTTY RECORD HIGHS AND MORE WIDESPREAD RECORD OVERNIGHT LOWS TO
LIMIT RELIEF. HEAT INDICES RISE RISE UPWARDS TO 105-110+F IN SOME
SPOTS, WITH FOCUS EXPANDING UP THROUGH THE PLAINS AND INTO THE
SOUTHWEST/ROCKIES THIS WEEKEND/EARLY NEXT WEEK.
ELSEWHERE, HEAVY RAINS/CONVECTION ARE FORECAST TO FOCUS DOWN INTO
THE EASTERN CAROLINAS/SOUTHEAST LATER WEEK GIVEN SUPPORT ALOFT AND
SLOWED FRONTAL PUSH. WPC EXCESSIVE RAINFALL MARGINAL RISK THURSDAY
AND FRIDAY ALSO HAVE EMBEDDED EASTERN CAROLINAS SLIGHT RISK AREAS.
MEANWHILE TO THE SOUTH, TROPICAL DEPRESSION "TWO" IS FORECAST TO
REACH TROPICAL STORM STRENGTH WHILE TRACKING WESTWARD NEAR THE
CENTRAL GULF COAST TOWARDS TEXAS INTO LATER THIS WEEK. DEEP
TROPICAL MOISTURE ASSOCIATED WITH THIS SYSTEM MAY FUEL AT LEAST A
LOCALIZED THREAT FOR HEAVY RAIN/RUNOFF ISSUES. A MARGINAL RISK AREA
WITH AN EMBEDDED SLIGHT RISK AREA IS IN PLACE FROM NORTHERN
FLORIDA/GULF COAST INTO EASTERN TEXAS THURSDAY AND FRIDAY.
SANTORELLI/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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