594
FXUS21 KWNC 061811
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT AUGUST 06 2026
SYNOPSIS: A RENEWED AREA OF MID-LEVEL HIGH PRESSURE OVER THE SOUTH-CENTRAL AND
SOUTHEASTERN CONTIGUOUS U.S. (CONUS) SUPPORTS A CONTINUATION OF EXTREME HEAT
RISKS FROM THE SOUTHERN PLAINS TO THE SOUTHEAST EARLY IN WEEK-2. ENHANCED
MOISTURE FROM THE NORTH AMERICAN MONSOON IS FAVORED TO FUNNEL INTO MUCH OF THE
INTERIOR WEST AND SPREAD EASTWARD INTO THE MIDWEST, TO INCREASE THE RISK OF
HEAVY PRECIPITATION. ANTECEDENT DRYNESS, COMBINED WITH LITTLE PRECIPITATION
FAVORED OVER THE NEXT TWO WEEKS SUPPORTS A RAPID ONSET DROUGHT (ROD) RISK FOR
PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS AND MISSISSIPPI VALLEY.
HAZARDS
MODERATE RISK OF EXTREME HEAT FOR PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS,
LOWER MISSISSIPPI VALLEY, AND SOUTHEAST, FRI-SUN, AUG 14-16.
SLIGHT RISK OF EXTREME HEAT FOR MUCH OF THE SOUTH-CENTRAL AND SOUTHEASTERN
CONUS, FRI-THU, AUG 14-20.
SLIGHT RISK OF HEAVY PRECIPITATION FOR THE DESERT SOUTHWEST, SOUTHERN GREAT
BASIN, AND CENTRAL AND SOUTHERN ROCKIES, AND PORTIONS OF THE PLAINS AND
MISSISSIPPI AND OHIO VALLEYS, FRI-MON, AUG 14-17.
RAPID ONSET DROUGHT (ROD) RISK FOR PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS
AND THE LOWER MISSISSIPPI VALLEY.
DETAILED SUMMARY
FOR SUNDAY AUGUST 09 - THURSDAY AUGUST 13:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY AUGUST 14 - THURSDAY AUGUST 20: LATE IN WEEK-1, BOTH THE GEFS AND
ECMWF ENSEMBLE FEATURE AN AMPLIFYING 500-HPA MEAN TROUGH CENTERED OVER THE
NORTHEASTERN U.S. WITH WEAKENING ABOVE-NORMAL POSITIVE HEIGHT DEPARTURES
OVERSPREADING THE SOUTHEASTERN AND WESTERN CONUS. HOWEVER, AS THIS TROUGHING
FEATURE DEAMPLIFIES BY THE START OF WEEK-2 (AUG 14), MODELS ARE IN AGREEMENT
FAVORING A RESTRENGTHENING RIDGE PATTERN OVER THE SOUTHEASTERN CONUS, WITH A
RIDGE AXIS EXTENDING NORTHWESTWARD INTO PARTS OF THE NORTHERN PLAINS AND
INTERIOR WEST. WHILE THE EVOLUTION OF THE MID-LEVEL PATTERN SUPPORTS A BRIEF
COOLDOWN OF THE ANOMALOUS WARMTH, TEMPERATURE TOOLS GENERALLY MAINTAIN A
CONTINUED HEAT RISK FOR MANY PARTS OF THE CONUS EARLY IN THE PERIOD. WITH MORE
TROUGHING FAVORED OFF OF THE WEST COAST, AND THE MEAN RIDGE AXIS DISPLACED TO
THE EAST, MUCH OF THE MONSOONAL MOISTURE SUPPLY IS EXPECTED TO EASE INTO PARTS
OF THE DESERT SOUTHWEST AND LOWER FOUR CORNERS. HOWEVER, RESIDUAL TROPOSPHERIC
MOISTURE AS WELL AS ADDED MOISTURE FROM THE PACIFIC LOOKS TO OVERSPREAD THE
INTERIOR WEST AND INTO THE PORTIONS OF THE MIDWEST, WHERE THERE CONTINUES TO BE
RISK OF HEAVY PRECIPITATION ALONG THE NORTHERN PERIPHERY OF THE ANOMALOUS
RIDGING FAVORED.
BASED ON A CONVERGENCE OF EVIDENCE IN THE RAW AND CALIBRATED TEMPERATURE TOOLS
AMONG THE DYNAMICAL MODELS, A MODERATE RISK OF EXTREME HEAT REMAINS ISSUED FOR
THE SOUTHERN PLAINS, ADJACENT CENTRAL PLAINS, AND INTO THE LOWER MISSISSIPPI
VALLEY WITH COVERAGE ADDED INTO PARTS OF THE SOUTHEAST AND FLORIDA PENINSULA.
WITHIN THE MODERATE RISK AREA, PROBABILISTIC EXTREME TOOLS (PETS) SHOW AT LEAST
30% CHANCES OF DAYTIME TEMPERATURES EXCEEDING THE 85TH PERCENTILE, AND
CALIBRATED HEAT TOOLS SHOW 30-50% CHANCES FOR EITHER TEMPERATURES OR HEAT INDEX
VALUES EXCEEDING THE 90TH PERCENTILE. FOR THE MODERATE RISK EXPANSION INTO THE
SOUTHEAST, RAW HEAT INDEX GUIDANCE DEPICT AN UPTICK OF MEAN VALUES REACHING
105-110 DEG F SINCE YESTERDAY WHERE THE NATIONAL BLEND OF MODELS (NBM) ALSO
SHOWS A NUMBER OF LOCATIONS WITH NIGHTTIME LOWS NEARING AND/OR BREAKING DAILY
RECORDS, WHERE LITTLE OVERNIGHT RELIEF TO DAYTIME HEAT IS EXPECTED. THE
MODERATE RISK AREA REMAINS VALID THROUGH AUG 16, BEFORE THE ANOMALOUS MID-LEVEL
RIDGING IS FAVORED TO DEAMPLIFY ONCE AGAIN. A BROADER SLIGHT RISK AREA OF
EXTREME HEAT ALSO REMAINS ISSUED FOR MUCH OF THE SOUTH-CENTRAL AND SOUTHEASTERN
U.S, WHERE TOOLS INDICATE LOWER PROBABILITIES FOR HEAT EXCEEDING HAZARDOUS
THRESHOLDS. THE SLIGHT RISK AREA ALSO REMAINS VALID FOR ALL OF WEEK-2 BASED ON
THE FAVORED PERSISTENCE OF AT LEAST 594 DM MEAN HEIGHTS AMONG THE DYNAMICAL
MODELS THROUGHOUT THE PERIOD..
ACROSS THE DESERT SOUTHWEST AND LOWER FOUR CORNERS, ANALYSIS OF PRECIPITABLE
WATER ANOMALIES FROM THE ECMWF AND GEFS ENSEMBLE DEPICT NEAR NORMAL VALUES
MAINLY OVER THE SONORAN DESERT, SUGGESTIVE OF A REDUCTION OF MONSOONAL MOISTURE
BEING ADVECTED INTO THE SOUTHWESTERN CONUS EARLY IN WEEK-2. WHILE PETS MAINTAIN
INCREASED CHANCES OF 3-DAY AMOUNTS EXCEEDING THE 85TH PERCENTILE THROUGHOUT THE
REGION, RAW PRECIPITATION TOOLS ALSO REFLECT A REDUCTION OF 3-DAY EXCEEDANCE
CHANCES RELATIVE TO YESTERDAY. AS A RESULT, THE MODERATE RISK OF HEAVY
PRECIPITATION AS WELL AS THE FLOODING POSSIBLE HAZARD IS DISCONTINUED IN THE
UPDATED OUTLOOK. DESPITE THE LOWERED RISK OF HEAVY PRECIPITATION, THIS REGION
IS STILL PRONE TO FLASH FLOODING EVEN WITH RELATIVELY SMALL PRECIPITATION
ACCUMULATIONS ESPECIALLY ALONG DRY CREEK BEDS (ARROYOS) AND IN CANYONS. CAUTION
SHOULD ALWAYS BE EXERCISED IN SUCH AREAS SHOULD THUNDERSTORM ACTIVITY INITIATE
NEARBY. MONSOONAL THUNDERSTORMS CAN ALSO PRODUCE DRY LIGHTNING, RESULTING IN
INCREASED WILDFIRE RISK. A SLIGHT RISK OVER HEAVY PRECIPITATION REMAINS ISSUED
OVER THE DESERT SOUTHWEST, BUT IS NOW EXPANDED TO INCLUDE PARTS OF THE INTERIOR
WEST, GREAT PLAINS, AND MISSISSIPPI VALLEY WHERE HIGHER PRECIPITABLE WATER
ANOMALIES ARE FAVORED ASSOCIATED WITH ENHANCED MOISTURE WORKING ITS WAY ALONG
THE NORTHERN PERIPHERY OF THE RIDGING CENTERED OVER THE SOUTHEASTERN U.S.
WITHIN THE HIGHLIGHTED REGION, RAW TOOLS SHOW INCREASED CHANCES OF 3-DAY
AMOUNTS EXCEEDING AN INCH THROUGHOUT MANY PARTS OF THE MIDWEST WHERE LOCALIZED
FLOODING RESULTING FROM MESOSCALE CONVECTIVE SYSTEMS (MCS) ACTIVITY IS POSSIBLE
THROUGH THE MIDDLE OF WEEK-2.
A RAPID ONSET DROUGHT (ROD) RISK REMAINS DESIGNATED AND IS EXPANDED TO INCLUDE
PARTS OF NORTHEASTERN TEXAS EASTWARD THROUGH NORTHERN MISSISSIPPI WHERE 30-DAY
PRECIPITATION DEFICITS ARE GREATER THAN 2 INCHES, AND NEAR TO BELOW NORMAL
RAINFALL AS WELL AS THE AFOREMENTIONED RISKS FOR HEAT TO ACCELERATE
EVAPOTRANSPIRATION RATES ARE FORECAST LATER IN AUGUST. ROD COVERAGE IS REMOVED
OVER PORTIONS OF KANSAS DUE TO INCREASED PRECIPITATION AMOUNTS FORECAST OVER
THE NEXT TWO WEEKS TO PROVIDE RELIEF.
ACROSS THE EASTERN PACIFIC, THE NATIONAL HURRICANE CENTER (NHC) IS MONITORING A
PAIR OF AREAS LOCATED NEAR 140W AND 110W BOTH WITH 30% CHANCES OF DEVELOPMENT
DURING THE NEXT SEVEN DAYS (AS OF 11AM PDT). FOR THE WESTERN WATCH AREA NEAR
140W, BOTH DYNAMICAL MODEL AND GOOGLE AI GUIDANCE HAVE BEEN CONSISTENT FAVORING
GROWING CHANCES FOR DEVELOPMENT LATER NEXT WEEK, WITH A LOW TRACKING NEAR THE
HAWAIIAN ISLANDS. WHILE THERE CONTINUES TO BE MUCH UNCERTAINTY ASSOCIATED WITH
THIS POTENTIAL TC AT THIS LEAD, PRECIPITATION TOOLS CONTINUE TO TREND WETTER
WITH THE ECMWF PET INDICATING INCREASED CHANCES FOR 3-DAY AMOUNTS EXCEEDING THE
85TH PERCENTILE. FOR MORE INFO ON THIS POTENTIAL SYSTEM, PLEASE REFER TO:
HTTPS://WWW.NHC.NOAA.GOV/
FORECASTER: NICK NOVELLA
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page