193
FXUS21 KWNC 131911
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JUNE 13 2026
SYNOPSIS: MID-LEVEL HIGH PRESSURE IS EXPECTED TO INCREASE CHANCES FOR EXTREME
HEAT FROM THE CENTRAL GULF COAST THROUGH FLORIDA AND THE SOUTH ATLANTIC COAST
INTO THE MIDDLE OF THE PERIOD. THEN, AS CONDITIONS IN THE SOUTHEAST EASE,
MID-LEVEL HIGH PRESSURE IS EXPECTED TO BUILD FARTHER WEST LATER WEEK-2,
BRINGING THE THREAT OF EXTREME HEAT TO THE SOUTH-CENTRAL STATES, THE DESERT
SOUTHWEST, AND THE CALIFORNIA VALLEYS DURING THE LAST HALF OF THE PERIOD. A
SURFACE FRONT ALONG THE SOUTHERN EDGE OF UNSEASONABLY COOL AIR IS PREDICTED
EARLY WEEK-2 FROM THE EAST-CENTRAL GREAT PLAINS THROUGH MUCH OF THE MIDDLE
MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS, ENHANCING CHANCES FOR HEAVY
PRECIPITATION THERE.
HAZARDS
SLIGHT RISK OF EXTREME HEAT ALONG THE CENTRAL GULF AND SOUTH ATLANTIC COASTS,
AND THE ENTIRE FLORIDA PENINSULA, SUN-THU, JUN 21-25.
SLIGHT RISK OF EXTREME HEAT FOR MUCH OF THE CENTRAL AND SOUTHERN PLAINS AND
LOWER MISSISSIPPI VALLEY, WED-SAT, JUN 24-27.
SLIGHT RISK OF EXTREME HEAT ACROSS THE DESERT SOUTHWEST AND CALIFORNIA VALLEYS,
WED-SAT, JUN 24-27.
SLIGHT RISK OF HEAVY PRECIPITATION FOR THE MIDDLE MISSISSIPPI, OHIO, AND
TENNESSEE VALLEYS AND ADJACENT AREAS, SUN-MON, JUN 21-22.
DETAILED SUMMARY
FOR TUESDAY JUNE 16 - SATURDAY JUNE 20:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SUNDAY JUNE 21 - SATURDAY JUNE 27: SUBTROPICAL MID-LEVEL RIDGING IS
EXPECTED TO EXTEND INTO THE FLORIDA PENINSULA AND ADJACENT AREAS OF THE CENTRAL
GULF AND SOUTHERN ATLANTIC COASTS THROUGH THE MIDDLE OF WEEK-2, INCREASING THE
ODDS FOR EXTREME HEAT IN THOSE AREAS. BIAS-CORRECTED GEFS AND ECENS HEAT INDEX
GUIDANCE FOR WEEK-2 DEPICTS VALUES PEAKING NEAR 105 DEG F, AND THE NATIONAL
BLEND OF MODELS (NBM) PREDICTS NEAR-RECORD OR RECORD HIGH NIGHTTIME MINIMUM
TEMPERATURES OF 76-81 DEG F ACROSS MUCH OF THE FLORIDA PENINSULA AND A FEW
NEARBY LOCATIONS. SOME LOCATIONS ON THE FLORIDA KEYS MAY NOT DROP BELOW 85 DEG
F ON ONE OR MORE NIGHTS. THE PROBABILISTIC EXTREMES TOOLS (PETS) FROM THE
EUROPEAN ENSEMBLE (ECENS), CANADIAN ENSEMBLE (CMCE), AND GEFS DEPICT THE BEST
CHANCES FOR HIGH TEMPERATURES ABOVE THE 85TH CLIMATOLOGICAL PERCENTILE ACROSS
THE FLORIDA PENINSULA (UP TO 40 PERCENT ON THE ECENS PET, AND 30 PERCENT ON THE
OTHERS). THE SLIGHT RISK OF EXTREME HEAT CONTINUES THROUGH THE MIDDLE OF WEEK-2
WHEN MOST TOOLS SHOW THE SUBTROPICAL MID-LEVEL RIDGE FLATTENING ACROSS THE
SOUTHEAST AND EMERGING FARTHER WEST. SOME TOOLS INDICATE INCREASED CHANCES FOR
EXTREME HEAT LATER IN WEEK-2 AS WELL, PARTICULARLY RAW TEMPERATURE OUTPUT AND
PETS FROM THE ECENS, BUT THERE IS TOO LITTLE CONSENSUS AMONG THE TOOLS TO
SUPPORT ANY EXTREME HEAT HAZARDS THEN, ALTHOUGH THE SITUATION WILL NEED TO BE
MONITORED.
DURING THE MIDDLE AND LATER PARTS OF WEEK-2, MID-LEVEL SUBTROPICAL RIDGING IS
EXPECTED TO EMERGE OVER THE CENTRAL OR INTERIOR WESTERN CONUS, BRINGING AN
INCREASED RISK OF EXTREME HEAT TO THE SOUTH-CENTRAL CONUS ALONG WITH MUCH OF
THE DESERT SOUTHWEST AND CALIFORNIA VALLEYS. INTERNAL SKILL-WEIGHTED GUIDANCE
BLENDING ECENS AND GEFS OUTPUT SHOWS 40 TO 60 PERCENT CHANCES FOR HEAT INDEXES
OVER 105 DEG F ACROSS MOST OF LOUISIANA, EASTERN AND NORTHEASTERN TEXAS, THE
CENTRAL TIER OF OKLAHOMA, AND THE LOWER RIO GRANDE VALLEY. THIS APPEARS LARGELY
DRIVEN BY UNUSUALLY HIGH HUMIDITY, AS THE PETS DEPICT ACTUAL AIR TEMPERATURES
REMAINING NEAR OR BELOW 100 DEG F WITH LOW CHANCES OF REACHING THE WARMEST 15
PERCENT OF THE CLIMATOLOGICAL ENVELOPE. CONSIDERABLY ABOVE NORMAL TEMPERATURES
COVER MOST OF THE INTERIOR WEST, INCLUDING THE ROCKIES, INTERMOUNTAIN WEST, AND
NORTHWEST DURING THE LAST HALF OF WEEK-2, BUT TEMPERATURES AND HEAT INDEXES ARE
EXPECTED TO REMAIN BELOW HAZARDS THRESHOLDS IN AN ABSOLUTE SENSE. THE PETS AND
INTERNAL HEAT INDEX GUIDANCE FROM THE ECENS AND GEFS DEPICT LOW CHANCES FOR
TEMPERATURES OR HEAT INDEXES TO TOP 100 DEG F IN THESE AREAS.
THE BUILDING MID-LEVEL SUBTROPICAL RIDGE ALSO INCREASES THE CHANCES FOR EXTREME
HEAT IN THE DESERT SOUTHWEST AND THE CALIFORNIA VALLEYS DURING THE LATTER HALF
OF WEEK-2. THE ECENS AND GEFS PETS SHOW 20 TO 40 PERCENT CHANCES OF
TEMPERATURES REACHING 110 DEG F IN THE DESERT SOUTHWEST ON SOME DAYS STARTING
AROUND THE MIDDLE OF WEEK-2, AND SIMILAR CHANCES FOR HIGHS TOPPING OUT OVER 100
DEG F IN THE CALIFORNIA VALLEYS. THE SAME TOOLS SHOW 20 TO 40 PERCENT CHANCES
FOR TEMPERATURES EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE. INTERNAL HEAT
INDEX GUIDANCE ALSO SHOWS INCREASED ODDS FOR TEMPERATURES OR HEAT INDEXES OF
105 DEG F OR HIGHER FOR AT LEAST ONE OF THE DAYS DURING THE LATTER HALF OF
WEEK-2.
A FRONTAL BOUNDARY (SEPARATING THE HEAT IN THE SOUTHEAST FROM UNSEASONABLY COOL
AIR FARTHER NORTH) IS EXPECTED TO BE DRAPED FROM THE EAST-CENTRAL GREAT PLAINS
EASTWARD THROUGH MOST OF THE MIDDLE MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS
EARLY WEEK-2. THIS IS EXPECTED TO DRIVE ABUNDANT PRECIPITATION AND ENHANCED
THUNDERSTORM ACTIVITY. THE PETS INDICATE AT LEAST A 20% CHANCE OF 3-DAY
PRECIPITATION EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE, WITH THE ECENS PET
SHOWING 30 TO 40 PERCENT CHANCES ACROSS THE TENNESSEE VALLEY AND NORTHERN
ARKANSAS. UNCALIBRATED ECENS OUTPUT DEPICTS A 50 TO 80 PERCENT CHANCE FOR
PRECIPITATION TOTALS TO EXCEED AN INCH DURING THE FIRST 2 DAYS OF THE PERIOD
THROUGHOUT THE SLIGHT RISK AREA, WITH A BAND SHOWING AT LEAST A 30 PERCENT
CHANCE FOR AMOUNTS TOPPING 2 INCHES FROM CENTRAL TENNESSEE THROUGH SOUTHWESTERN
MISSISSIPPI. TOWARD THE MIDDLE OF WEEK-2, MID-LEVEL TROUGHING AND UNUSUALLY
COOL SURFACE AIR IS EXPECTED TO MODERATE AND PULL NORTHEASTWARD, WEAKENING THE
FRONTAL BOUNDARY AND BRINGING AN END TO THE HEAVY PRECIPITATION THREAT.
FORECASTER: RICH TINKER
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