481
FXUS21 KWNC 011801
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT AUGUST 01 2026
SYNOPSIS: A PERSISTENT AND MODERATELY STRONG AREA OF MID-LEVEL HIGH PRESSURE
FAVORS ABOVE-NORMAL TEMPERATURES FOR NEARLY THE ENTIRE CONTIGUOUS U.S. (CONUS)
DURING EARLY TO MID-AUGUST. THE WEST, CENTRAL TO SOUTHERN GREAT PLAINS, AND
SOUTHEAST HAVE AN ELEVATED CHANCE OF EXTREME HEAT. ANTECEDENT DRYNESS ALONG
WITH THE LIKELIHOOD OF ABOVE-NORMAL TEMPERATURES AND BELOW-NORMAL PRECIPITATION
DURING THE NEXT TWO WEEKS SUPPORTS AN INCREASED RISK FOR THE RAPID ONSET OF
DROUGHT TO PARTS OF THE CENTRAL TO SOUTHERN GREAT PLAINS AND OZARKS REGION. AN
ENHANCED MONSOON IS FORECAST WHICH INCREASES THE CHANCE OF HEAVY PRECIPITATION
AND FLASH FLOODING FROM THE DESERT SOUTHWEST NORTH TO THE CENTRAL ROCKIES.
HAZARDS
MODERATE RISK OF EXTREME HEAT FOR PARTS OF CALIFORNIA, THE GREAT BASIN, AND
SOUTHWEST, SUN-MON, AUG 9-10.
MODERATE RISK OF EXTREME HEAT FOR MUCH OF THE CENTRAL TO SOUTHERN GREAT PLAINS
AND MIDDLE TO LOWER MISSISSIPPI VALLEY, SUN-SAT, AUG 9-15.
SLIGHT RISK OF EXTREME HEAT FOR MOST OF THE CONUS EXCLUDING THE GREAT LAKES
REGION, NORTHEAST, AND APPALACHIANS, SUN-SAT, AUG 9-15.
SLIGHT RISK OF HEAVY PRECIPITATION FOR THE DESERT SOUTHWEST AND FOUR CORNERS
REGION, SUN-SAT, AUG 9-15.
SLIGHT RISK OF HEAVY PRECIPITATION FOR THE MIDWEST AND CENTRAL APPALACHIANS,
SUN-WED, AUG 9-12.
INCREASED RISK FOR RAPID ONSET DROUGHT (ROD) ACROSS PARTS OF THE CENTRAL TO
SOUTHERN GREAT PLAINS AND OZARKS REGION.
DETAILED SUMMARY
FOR TUESDAY AUGUST 04 - SATURDAY AUGUST 08:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SUNDAY AUGUST 09 - SATURDAY AUGUST 15: THE GEFS AND ECENS ARE IN GOOD
AGREEMENT THAT A BROAD AND MODERATELY STRONG 500-HPA RIDGE PERSISTS OVER THE
SOUTHERN TWO-THIRDS OF THE CONUS THROUGH MID-AUGUST. COMPARED TO THE BEGINNING
OF THE MONTH, THESE ENSEMBLE MEANS DEPICT A SLIGHTLY WEAKER RIDGE (500-HPA
HEIGHTS BELOW 597 DM) BUT THERE REMAINS EITHER A SLIGHT OR MODERATE RISK OF
EXTREME HEAT FOR MUCH OF THE WEST, CENTRAL TO SOUTHERN GREAT PLAINS, AND
SOUTHEAST FROM AUG 9 TO 15. A MODERATE RISK OF EXTREME HEAT, VALID AUG 9 AND
10, IS POSTED FOR PARTS OF CALIFORNIA AND THE GREAT BASIN WHERE THE NWS
HEATRISK TOOL INDICATES MORE THAN A 40 PERCENT CHANCE OF REACHING THE MAJOR
HEATRISK CATEGORY. ALSO, A CONSENSUS OF THE GEFS AND ECENS PROBABILISTIC
EXTREMES TOOLS (PETS) GENERALLY DEPICT THAT MAXIMUM TEMPERATURES HAVE AT LEAST
A 40 PERCENT CHANCE OF EXCEEDING THE 85TH PERCENTILE. MAXIMUM TEMPERATURES ARE
EXPECTED TO REACH 100 DEG F IN THE LOWER ELEVATIONS OF THE GREAT BASIN AND 110
DEG F IN SOUTHERN NEVADA AND SOUTHEASTERN CALIFORNIA. TO THE EAST OF THE
CONTINENTAL DIVIDE, A MODERATE RISK OF EXTREME HEAT CONTINUES FOR THE ENTIRETY
OF THE WEEK-2 PERIOD AS THE GEFS AND ECENS SHOW A STRENGTHENING RIDGE WITH
TIME. THE MODERATE RISK AREA INCLUDES MUCH OF THE CENTRAL AND SOUTHERN GREAT
PLAINS EAST TO THE MIDDLE AND LOWER MISSISSIPPI VALLEY WHERE ENSEMBLE MEANS
INDICATE TEMPERATURE ANOMALIES OF 5-10+ DEG F ABOVE NORMAL. MAXIMUM HEAT INDEX
VALUES ARE FORECAST TO RANGE FROM 100-105 DEG F IN THE CENTRAL GREAT PLAINS TO
105-110 DEG F IN THE SOUTHERN GREAT PLAINS AND MIDDLE TO LOWER MISSISSIPPI
VALLEY. THE PERSISTENCE OF THE ANOMALOUS 500-HPA RIDGE SUPPORTS A SLIGHT RISK
OF EXTREME HEAT FOR A MAJORITY OF THE CONUS THROUGH THE END OF WEEK-2, AUG 15.
ANOMALOUSLY WARM TEMPERATURES AND DRIER-THAN-NORMAL CONDITIONS ARE EXPECTED TO
MAINTAIN AN ELEVATED WILDFIRE DANGER ACROSS THE NORTHERN INTERMOUNTAIN WEST
THROUGH MID-AUGUST.
BY AUG 9TH, THE ENSEMBLE MEAN SOLUTIONS REMAIN CONSISTENT THAT THE 500-HPA
RIDGE AXIS BECOMES CENTERED OVER THE FOUR CORNERS REGION WHICH IS A FAVORABLE
SETUP FOR AN ENHANCED MONSOON. IN ADDITION, A WEAKENING RIDGE ALOFT SHOULD
ALLOW FOR MORE WIDESPREAD CONVECTION. THE PREDICTED 500-HPA HEIGHT PATTERN
ALONG WITH THE GEFS AND ECENS PETS (> 20% CHANCE OF 3-DAY AMOUNTS EXCEEDING THE
85TH PERCENTILE) SUPPORT A SLIGHT RISK OF HEAVY PRECIPITATION ACROSS THE DESERT
SOUTHWEST FROM AUG 9 TO 15. BASED ON 24-HOUR AMOUNTS FROM THE UNCALIBRATED GEFS
AND ECENS, THE SLIGHT RISK OF HEAVY PRECIPITATION WAS EXTENDED NORTH TO THE
CENTRAL ROCKIES. ANY LOCALLY HEAVY RAINFALL COULD TRIGGER FLASH FLOODING,
ESPECIALLY IN BURN SCAR AREAS.
MULTI-MODEL ENSEMBLE MEANS AGREE THAT A 500-HPA TROUGH SHIFTS EAST NEAR THE
GREAT LAKES WHICH FAVORS MESOSCALE CONVECTIVE SYSTEMS (MCS) TO TRACK
SOUTHEASTWARD ACROSS THE MIDWEST. GIVEN THE VERY HUMID AIRMASS, ANY MCS WILL BE
CAPABLE OF PRODUCING FLASH FLOODING. PATTERN RECOGNITION AND 1 TO 3-DAY
PRECIPITATION AMOUNTS FROM THE GEFS AND ECENS WERE USED AS GUIDES TO DEFINE A
SLIGHT RISK OF HEAVY PRECIPITATION. IT IS VALID THROUGH AUG 12TH UNTIL 500-HPA
HEIGHTS BEGIN TO RISE ACROSS THE EAST-CENTRAL CONUS.
A RAPID ONSET DROUGHT (ROD) RISK IS DESIGNATED FOR PARTS OF THE CENTRAL AND
SOUTHERN PLAINS ALONG WITH THE OZARKS REGION WHERE 30-DAY PRECIPITATION
DEFICITS ARE GREATER THAN 2 INCHES AND CONTINUED DRYNESS AND HEAT ARE FORECAST
THROUGH EARLY TO MID-AUGUST.
FORECASTER: BRAD PUGH
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