296
FXUS21 KWNC 281806
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JUNE 28 2026
SYNOPSIS: EXTREME HEAT IS LIKELY TO CONTINUE INTO WEEK-2 ACROSS MANY AREAS OF
THE CENTRAL AND EASTERN CONTIGUOUS U.S. (CONUS) ASSOCIATED WITH ANOMALOUS
MID-LEVEL HIGH PRESSURE. ANTICIPATED HIGH DEWPOINTS FAVOR HEAT INDEX VALUES
EXCEEDING 100 TO 105 DEG F OVER MANY AREAS WITH WARM NIGHTS LIMITING OVERNIGHT
RELIEF. AS THE MID-LEVEL HIGH SHIFTS WESTWARD, SOME HEAT RELIEF IS FORECAST
ACROSS THE EASTERN SEABOARD, BUT WITH EXTREME HEAT POTENTIAL INCREASING ACROSS
PARTS OF THE WESTERN CONUS. SURFACE HIGH PRESSURE OFF THE WEST COAST IN WEEK-2
INCREASES CHANCES FOR EPISODES OF HIGH WINDS ACROSS THE PACIFIC NORTHWEST AND
CALIFORNIA THROUGH MUCH OF THE PERIOD.
HAZARDS
MODERATE RISK OF EXTREME HEAT FOR THE EASTERN CENTRAL AND SOUTHERN PLAINS,
CENTRAL AND LOWER MISSISSIPPI VALLEY, SOUTHEAST ATLANTIC STATES, AND
MID-ATLANTIC, MON, JUL 6.
SLIGHT RISK OF EXTREME HEAT ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS,
MON-WED, JUL 6-8.
SLIGHT RISK OF EXTREME HEAT ACROSS MUCH OF THE GREAT BASIN, NORTHERN
INTERMOUNTAIN, SOUTHWEST, AND ROCKIES, MON-FRI, JUL 6-10.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF CALIFORNIA AND THE PACIFIC NORTHWEST,
MON-SUN, JUL 6-12.
DETAILED SUMMARY
FOR WEDNESDAY JULY 01 - SUNDAY JULY 05:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR MONDAY JULY 06 - SUNDAY JULY 12: A MAJOR HEAT WAVE IS FORECAST TO BE
ONGOING ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS AT THE START OF WEEK-2.
FOR THE EASTERN SEABOARD, THE PEAK OF THE HEAT IS LIKELY TO OCCUR DURING THE
LATE WEEK-1 TIMEFRAME, WITH MID-LEVEL RIDGING RETROGRADING FARTHER TO THE WEST
AT THE BEGINNING OF WEEK-2. DESPITE THESE HEIGHT TRENDS, THE SURFACE
TEMPERATURE FORECAST FROM THE ECENS AND GEFS PROBABILISTIC EXTREMES TOOLS
(PETS) STILL HIGHLIGHT ELEVATED CHANCES FOR MAXIMUM TEMPERATURES TO EXCEED THE
85TH CLIMATOLOGICAL PERCENTILE. THE GEFS PET HAS A MORE ROBUST SIGNAL FOR JUL 6
RELATIVE TO YESTERDAY'S FORECAST. SEPARATELY, A SKILL WEIGHTED HEAT RISK TOOL
INDICATES GREATER THAN 40% CHANCES FOR HEAT INDEX VALUES TO EXCEED 105 DEG F
AND THE 90TH PERCENTILE. THE OVERNIGHT MINIMUM TEMPERATURE FORECAST FROM THE
NATIONAL BLEND OF MODELS (NBM) CONTINUES TO HIGHLIGHT A SIGNIFICANT NUMBER OF
RECORDS BY THE BEGINNING OF WEEK-2. THE DETERMINISTIC ECMWF AND GFS FORECAST
MAXIMUM APPARENT TEMPERATURES NEAR 105+ DEG F FOR THE MID-ATLANTIC AND
SOUTHEAST ATLANTIC STATES, AND 105 TO 110 DEG F OVER THE EASTERN CENTRAL AND
SOUTHERN PLAINS AND MIDDLE AND LOWER MISSISSIPPI VALLEY.
AS SUCH, A MODERATE RISK OF HEAT IS FORECAST FOR THE MID-ATLANTIC AND SOUTHEAST
ATLANTIC COAST FOR JUL 6. A SEPARATE RISK IS DESIGNATED FOR THE EASTERN CENTRAL
AND SOUTHERN PLAINS INTO THE MIDDLE AND LOWER MISSISSIPPI VALLEY, ALSO FOR JUL
6. A SMALL AREA OF GEORGIA AND ALABAMA WAS REMOVED FROM THE MODERATE RISK TODAY
WITH CONTINUED WEAKENING OF THE HEAT SIGNAL ACROSS THIS REGION. HOWEVER, A
BROADER SLIGHT RISK REMAINS VALID THROUGH JUL 8 ACROSS MUCH OF THE CENTRAL AND
EASTERN CONUS.
BY DAY-8, THE 0Z ECMWF, GEFS, AND CANADIAN ENSEMBLES ALL DEPICT A 594-596 DM
RIDGE ACROSS THE FOUR CORNERS, WHICH COULD RESULT IN EXTREME HEAT CONDITIONS
EMERGING ACROSS PORTIONS OF THE INTERIOR WEST AND PERSISTING THROUGH AT LEAST
THE MIDDLE OF WEEK-2. THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY REGARDING THE
SURFACE REFLECTION OF THE MID-LEVEL HEIGHT PATTERN WITH PET TOOLS STILL NOT
BRINGING MODERATE RISK CHANCES INTO THE REGION. HOWEVER, THE WEATHER PREDICTION
CENTER (WPC) PROBABILISTIC HEATRISK TOOL SHOWS INCREASING SIGNALS FOR MAJOR
HEATRISK ACROSS THE WEST BY THE BEGINNING OF WEEK-2. THEREFORE, AN ADDITIONAL
SLIGHT RISK (20-40 PERCENT CHANCE) OF EXTREME HEAT IS VALID JULY 6-10, ACROSS
MUCH OF THE INTERIOR WESTERN US, EXCLUDING MOST AREAS WEST OF THE SIERRA NEVADA
AND THE NORTHERN ROCKIES.
SURFACE HIGH PRESSURE OFF THE WEST COAST AND MID-LEVEL LOW PRESSURE, ALONG WITH
THERMAL LOW PRESSURE OVER THE GREAT BASIN INCREASE CHANCES FOR EPISODES OF HIGH
WINDS DURING WEEK-2. THE GEFS AND ECMWF PETS INDICATE AT LEAST A 20 PERCENT
CHANCE OF WIND SPEEDS EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE AND 25-MPH.
THEREFORE, A SLIGHT RISK OF HIGH WINDS IS POSTED ACROSS THIS REGION.
ACROSS THE SOUTHWESTERN CONUS, THE RIDGE AXIS IS FORECAST TO MOVE TOWARDS A
MORE FAVORABLE POSITION FOR ENHANCED MONSOONAL MOISTURE ADVECTION AND INCREASED
PRECIPITATION OVER PARTS OF THE DESERT SOUTHWEST. ALTHOUGH PETS SHOW INCREASED
CHANCES OF 3-DAY PRECIPITATION EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE
OVER THE DESERT SOUTHWEST AND INTO THE CENTRAL ROCKIES DURING THE SECOND HALF
OF WEEK-2, BOTH RAW AND CALIBRATED PRECIPITATION AMOUNTS IN THE ENSEMBLE MEANS
REMAIN FAIRLY LOW, PRECLUDING A CORRESPONDING PRECIPITATION HAZARD AT THIS
TIME. LOCALIZED THUNDERSTORMS ARE STILL POSSIBLE AND THIS AREA WILL CONTINUE TO
BE MONITORED WITH ENSEMBLE GUIDANCE INDICATING PRECIPITABLE WATER INCREASING
DURING THE WEEK-2 PERIOD.
TRANSIENT SHORTWAVES MOVING ACROSS ALASKA FAVOR PERIODS OF ENHANCED
PRECIPITATION ACROSS MUCH OF THE STATE, ALONG WITH A TILT TOWARD BELOW-AVERAGE
TEMPERATURES. HOWEVER, PRECIPITATION AND TEMPERATURE VALUES ARE EXPECTED TO
REMAIN BELOW HAZARDOUS THRESHOLDS.
FORECASTER: RYAN BOLT
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