337
FXUS21 KWNC 231844
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JUNE 23 2026
SYNOPSIS: STRONG MID-LEVEL HIGH PRESSURE IS FORECAST TO CONTINUE FROM THE END
OF WEEK-1 INTO WEEK-2 ACROSS THE EASTERN CONTIGUOUS U.S. (CONUS) AT THE
BEGINNING OF WEEK-2, SHIFTING TO CENTRAL CONUS BY THE MIDDLE OF THE PERIOD,
BRINGING INCREASED LIKELIHOOD OF EXTREME HEAT FOR THESE AREAS. A HIGH RISK IS
DESIGNATED FOR THE MID-ATLANTIC TO SOUTH CAROLINA, JUL 1-2, WITH A BROADER
MODERATE EXTENDING TO GEORGIA FOR THE SAME PERIOD. A MODERATE RISK IS ALSO
DESIGNATED FOR THE CENTRAL AND SOUTHERN PLAINS, JUL 1-3, WITH A BROAD AREA OF
SLIGHT RISK HIGHLIGHTED FOR MUCH OF THE CENTRAL AND EASTERN CONUS, JUL 1-4.
HIGH DEWPOINTS INCREASE HEAT INDEX VALUES WITH MANY AREAS APPROACHING OR
EXCEEDING 100 DEG F IN THE MODERATE RISK AREAS. SURFACE LOWS ACROSS THE WEST
AND ADJACENT SURFACE HIGH PRESSURE ACROSS THE NORTHEASTERN PACIFIC MAY INDUCE A
TIGHT PRESSURE GRADIENT ALONG COASTAL PARTS OF NORTHERN CALIFORNIA RESULTING IN
EPISODIC HIGH WINDS ACROSS THE REGION.
HAZARDS
HIGH RISK OF EXTREME HEAT FOR PARTS OF THE MID-ATLANTIC AND SOUTH CAROLINA,
WED-THU, JUL 1-JUL 2.
MODERATE RISK OF EXTREME HEAT FOR THE MID-ATLANTIC AND SOUTHEASTERN U.S.,
WED-THU, JUL 1-JUL 2.
MODERATE RISK OF EXTREME HEAT FOR THE GREAT LAKES REGION, OHIO, MIDDLE AND
LOWER MISSISSIPPI, AND TENNESSEE VALLEYS, WED-FRI, JUL 1-3.
MODERATE RISK OF EXTREME HEAT FOR THE SOUTHERN AND CENTRAL PLAINS, WED-FRI, JUL
1-3.
SLIGHT RISK OF EXTREME HEAT FOR MUCH OF THE CENTRAL AND EASTERN CONUS, WED-SAT,
JUL 1-4.
SLIGHT RISK OF HIGH WINDS FOR COASTAL PORTIONS OF NORTHERN CALIFORNIA, WED-TUE,
JUL 1-7.
DETAILED SUMMARY
FOR FRIDAY JUNE 26 - TUESDAY JUNE 30:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR WEDNESDAY JULY 01 - TUESDAY JULY 07: THE 0Z GEFS ENSEMBLE MEAN, ASSOCIATED
AI SOLUTION, AND CMCE HAVE INCREASED THE STRENGTH OF THE MID-LEVEL HIGH
PRESSURE ACROSS THE CENTRAL AND EASTERN CONUS COMPARED TO YESTERDAY, COMING
MORE IN LINE WITH THE ECENS. THIS RIDGE IS ANTICIPATED TO BE CENTERED INITIALLY
ACROSS THE SOUTHEASTERN CONUS, WITH MAXIMUM 500 HPA HEIGHTS OF 595 DAM,
RETROGRADING TO THE SOUTH-CENTRAL CONUS BY AROUND DAY 10 (JUL 3). THIS PATTERN
SUPPORTS INCREASED LIKELIHOOD OF EXTREME HEAT FOCUSED INITIALLY ACROSS PARTS OF
THE EASTERN CONUS AT THE BEGINNING OF WEEK-2, SHIFTING WESTWARD TO THE CENTRAL
CONUS BY THE MIDDLE OF WEEK-2. MID-LEVEL TROUGHING IS ANTICIPATED TO DEVELOP
ACROSS THE EAST COAST BY THE LATTER PART OF THE PERIOD WHICH COULD PROVIDE SOME
RELIEF IN HEAT-AFFECTED AREAS.
OVERALL THE AREAS HIGHLIGHTED WITH RISK OF EXTREME HEAT HAVE BEEN EXPANDED
SPATIALLY RELATIVE TO YESTERDAY'S FORECAST. A HIGH RISK (GREATER THAN 60%
CHANCE) OF EXTREME HEAT IS DESIGNATED FOR PARTS OF THE MID-ATLANTIC AND SOUTH
CAROLINA, JUL 1-2, WITH A BROADER AREA OF MODERATE RISK (40-60% CHANCE)
EXTENDED FURTHER SOUTH INTO PARTS OF GEORGIA. A MODERATE RISK IS ALSO ADDED
TODAY ACROSS THE GREAT LAKES REGION, OHIO, MIDDLE AND LOWER MISSISSIPPI, AND
TENNESSEE VALLEYS, JUL 1-3. MODERATE RISK IS ALSO DESIGNATED ACROSS THE CENTRAL
AND SOUTHERN PLAINS FOR THE SAME PERIOD. A BROAD AREA OF SLIGHT RISK COVERS
MUCH OF THE CENTRAL AND EASTERN CONUS, JUL 1-4. THE GEFS AND ECENS
PROBABILISTIC EXTREMES TOOLS (PETS) INDICATE THE HIGHEST PROBABILITIES (>
50-60%) FOR MAXIMUM TEMPERATURES REACHING THE 85TH PERCENTILE OVER THE OHIO
VALLEY. HIGH HUMIDITY IS ANTICIPATED TO AMPLIFY HEAT INDEX VALUES IN MANY OF
THE HAZARDOUS HEAT AREAS. VARIOUS HEAT TOOLS SHOW ELEVATED PROBABILITIES ACROSS
THE DESIGNATED MODERATE AND HIGH RISK AREAS, WITH HEAT INDEX VALUES POSSIBLY
EXCEEDING 100 DEG F IN THE MODERATE RISK AREAS, AND 105 DEG F WHERE THE HIGH
RISK IS IDENTIFIED ACROSS THE MID-ATLANTIC AND SOUTH CAROLINA AND CENTRAL AND
SOUTHERN PLAINS. THE NATIONAL BLEND OF MODELS (NBM) INDICATES POSSIBLE NEAR OR
RECORD BREAKING HIGH TEMPERATURES ACROSS PARTS OF THE EAST, WITH EVEN MORE
WIDESPREAD POSSIBLE HIGH NIGHTTIME TEMPERATURES IN THE UPPER 70S TO LOWER 80S
DEG F. THEREFORE, NIGHTTIME RECOVERY AND RELIEF WILL BE VERY LIMITED. THE
SECOND CONSIDERATION IS THE NATION'S 250TH ANNIVERSARY THIS JULY 4TH, WITH LOTS
OF OUTDOOR ACTIVITIES PLANNED. STAYING HYDRATED AND LIMITING EXPOSURE TO VERY
HOT, HUMID WEATHER IS VERY IMPORTANT, ESPECIALLY VULNERABLE POPULATIONS
INCLUDING OLDER ADULTS.
POSSIBLE SURFACE LOWS ACROSS THE WEST WITH ADJACENT SURFACE HIGH PRESSURE OVER
THE NORTHEASTERN PACIFIC MAY RESULT IN A TIGHT PRESSURE GRADIENT ACROSS PARTS
OF THE WEST COAST. A SLIGHT RISK OF HIGH WINDS IS DESIGNATED FOR COASTAL
PORTIONS OF NORTHERN CALIFORNIA FOR THE DURATION OF WEEK-2.
AN UPSTREAM MID-LEVEL TROUGH OVER THE NORTHERN ROCKIES AND NORTHERN PLAINS AND
A SURFACE LOW OVER SOUTH-CENTRAL CANADA WITH TRAILING FRONT AT THE END OF
WEEK-1 MAY LINGER INTO THE ONSET OF WEEK-2 BRINGING LOCALIZED ENHANCED RAINFALL
ASSOCIATED WITH MESOSCALE CONVECTIVE SYSTEM (MCS) ACTIVITY TO PARTS OF THE
UPPER MIDWEST. YESTERDAY'S HEAVY PRECIPITATION HAZARD WAS DISCONTINUED DUE TO
TIMING OUT OF THE MORE SIGNIFICANT POTENTIAL FOR HEAVY RAINFALL, WITH MORE
LOCALIZED POTENTIAL FOR THE START OF WEEK-2.
FURTHER SOUTH, A CENTER OF 500 HPA HEIGHTS EXCEEDING 594 DM IS INDICATED BY
MULTIPLE ENSEMBLE MEANS ACROSS EASTERN PORTIONS OF THE FOUR CORNERS REGION
DURING WEEK-2 WHICH WOULD BE FAVORABLE FOR THE SOUTHWEST MONSOON. PETS SHOW
SOME PARTS OF THE VERY SOUTHERN PORTION OF ARIZONA HAVING 3-DAY RAINFALL TOTALS
EXCEEDING 0.5 INCHES. THIS AREA IS STILL LIMITED AT THIS TIME BUT WILL BE
MONITORED CLOSELY IN THE UPCOMING DAYS.
FORECASTER: MELISSA OU
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