404
FXUS21 KWNC 111800
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JUNE 11 2025
SYNOPSIS: AN AREA OF WEAK MID-LEVEL HIGH PRESSURE IS FORECAST TO REMAIN IN
PLACE ACROSS THE EASTERN CONTIGUOUS U.S. (CONUS) DURING THE WEEK-2 PERIOD. THIS
SUPPORTS A SLIGHT RISK OF EXTREME HEAT FOR PORTIONS OF THE CENTRAL CONUS. ALONG
THE NORTHERN PERIPHERY OF THE MID-LEVEL HIGH, HEAVY PRECIPITATION IS POSSIBLE
IN THE NORTHERN PLAINS, UPPER MISSISSIPPI VALLEY AND GREAT LAKES. IN SOUTHERN
TEXAS HEAVY PRECIPITATION IS ALSO POSSIBLE ASSOCIATED WITH AN EASTERLY WAVE.
EXTREME HEAT REMAINS POSSIBLE FOR PORTIONS OF THE DESERT SOUTHWEST. MEANWHILE,
WINDY CONDITIONS ARE SOMEWHAT FAVORABLE IN PORTIONS OF THE SOUTHERN PLAINS AND
ALONG PARTS OF THE COAST OF CALIFORNIA AND OREGON.
HAZARDS
SLIGHT RISK OF EXTREME HEAT FOR PORTIONS OF THE CENTRAL PLAINS, LOWER AND
MIDDLE MISSISSIPPI VALLEY AND SURROUNDING AREAS, THU-SAT, JUN 19-21.
SLIGHT RISK OF EXTREME HEAT FOR PORTIONS OF THE DESERT SOUTHWEST, THU-SAT, JUN
19-21.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF SOUTHERN TEXAS, THU-SAT, JUN
19-21.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE NORTHERN PLAINS, UPPER
MISSISSIPPI VALLEY, AND GREAT LAKES, THU-SUN, JUN 19-22.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE SOUTHERN PLAINS, THU-WED, JUN
19-25.
SLIGHT RISK OF HIGH WINDS FOR COASTAL REGIONS FROM CENTRAL OREGON SOUTH THROUGH
CENTRAL CALIFORNIA, THU-WED, JUN 19-25.
DETAILED SUMMARY
FOR SATURDAY JUNE 14 - WEDNESDAY JUNE 18:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY JUNE 19 - WEDNESDAY JUNE 25: POSITIVE 500-HPA HEIGHT ANOMALIES ARE
FORECAST ACROSS MUCH OF THE CONUS EARLY IN THE WEEK-2 PERIOD, WITH THE
STRONGEST ANOMALIES OVER THE EASTERN CONUS. HOWEVER, THESE ANOMALIES ARE NOT
PARTICULARLY ROBUST AND NORMALIZED 500-HPA HEIGHT ANOMALIES ARE ONLY 1 TO 1.5
STANDARD DEVIATIONS ABOVE NORMAL. THE NORMALIZED ANOMALIES ARE STRONGEST FROM
THE GULF OF AMERICA NORTHWARD INTO THE CENTRAL CONUS. THE MID-LEVEL RIDGE AXIS
IS ALSO EXPECTED TO BE LOCATED OVER THIS REGION DURING MUCH OF WEEK-2.
AT THE SURFACE, DYNAMICAL MODEL GUIDANCE INDICATES A STRONG BERMUDA HIGH
PRESSURE AND RETURN FLOW OFF THE GULF HELPING TO ENHANCE LOW LEVEL MOISTURE AND
INDUCING A WARM AND STICKY AIRMASS ACROSS THE CENTRAL CONUS. A SKILL WEIGHTED
BIAS-CORRECTED HEAT INDEX FORECAST OF THE GEFS AND ECENS, INDICATES 30-40%
CHANCES OF THE HEAT INDEX EXCEEDING 105 DEG F ACROSS PARTS OF THE CENTRAL
PLAINS, MIDDLE AND LOWER MISSISSIPPI VALLEYS. THIS HEAT SIGNAL IS ALSO
SUPPORTED BY THE PROBABILISTIC EXTREMES TOOLS (PETS) FROM BOTH OF THOSE MODELS
AS WELL. ADDITIONALLY, DETERMINISTIC GUIDANCE SUPPORTS HEAT INDICES ABOVE 100
DEG F ACROSS THESE REGIONS. THEREFORE, A SLIGHT RISK OF EXTREME HEAT IS POSTED
FOR THE PREVIOUSLY DESCRIBED AREAS FOR THU-SAT, JUN 19-21.
WHILE ABOVE-NORMAL TEMPERATURES REMAIN LIKELY ACROSS THE OHIO VALLEY, IT LOOKS
LESS CERTAIN THAT TEMPERATURES WILL REACH HAZARDOUS THRESHOLDS, THEREFORE THIS
HAZARD HAS BEEN DISCONTINUED TODAY. ELSEWHERE IN THE EAST, TEMPERATURES ARE
FORECAST TO BE ABOVE-NORMAL BUT MAY NOT REACH HAZARDOUS CRITERIA BUT PEOPLE
SENSITIVE TO EXTREME HEAT SHOULD REMAIN AWARE OF POSSIBLE CHANGES IN THE
FORECAST.
IN THE DESERT SOUTHWEST, DYNAMICAL GUIDANCE REMAINS SUPPORTIVE OF TEMPERATURES
APPROACHING HEAT CRITERIA. TEMPERATURES OF 105 TO 110 ARE SUPPORTED BY MANY
TOOLS AFTER A BRIEF RESPITE AT THE END OF WEEK-1. THEREFORE, A SLIGHT RISK OF
EXTREME HEAT IS POSTED FOR THE DESERT SOUTHWEST FOR JUN 19-21.
IN THE NORTHERN PLAINS INTO THE GREAT LAKES, ALONG THE NORTHERN PERIPHERY OF
THE MID-LEVEL RIDGE, DYNAMICAL GUIDANCE IS INDICATING INCREASED CHANCES OF ONE
OR MORE MESOSCALE CONVECTIVE SYSTEMS (MCS) TO DEVELOP AND BRING CHANCES FOR
HEAVY PRECIPITATION TO THE REGION. THE ECENS REFORECAST AND PET SHOW INCREASED
CHANCES FOR ABOVE-NORMAL PRECIPITATION DURING WEEK-2 AND PRECIPITATION
EXCEEDING THE 85TH PERCENTILE IN THE FIRST 3 DAYS OF THE PERIOD, RESPECTIVELY.
SIMILARLY, THE STATISTICAL ANALOG TOOL HIGHLIGHTS INCREASED CHANCES FOR
ABOVE-NORMAL PRECIPITATION ACROSS THIS REGION AS WELL. THEREFORE, A SLIGHT RISK
OF HEAVY PRECIPITATION IS POSTED FOR JUN 19-22 IN THIS REGION.
IN SOUTHERN TEXAS, AN EASTERLY WAVE OFF THE BAY OF CAMPECHE, BRINGS INCREASED
CHANCES FOR HEAVY PRECIPITATION TO THE AREA. THE PETS FROM THE GEFS AND ECENS
INDICATED 20-40% CHANCES FOR 3 DAY PRECIPITATION AMOUNTS TO EXCEED THE 85TH
CLIMATOLOGICAL PERCENTILE AND 1 INCH. THIS COULD LEAD TO CHANCES OF FLASH
FLOODING DUE TO THE SHORT TIME IN WHICH PRECIPITATION IS FORECAST TO FALL AND
THE NATURE OF THE WATERSHEDS IN THE REGION. THEREFORE, A SLIGHT RISK OF HEAVY
PRECIPITATION IS FORECAST FOR JUN 19-21.
MODELS GENERALLY DEPICT FAIRLY STRONG WINDS AT THE SOUTHERN END OF THE GULF
MOISTURE INFLOW. WHILE THE PETS ARE RATHER MIXED, ENSEMBLE MEAN WIND SPEEDS
FROM THE ECMWF AND GEFS BOTH INDICATE PEAK DAILY WIND SPEEDS OF AT LEAST 20MPH
OVER WESTERN PORTIONS OF THE SOUTHERN PLAINS THROUGHOUT THE FORECAST PERIOD,
THEREFORE A SLIGHT RISK OF EPISODIC HIGH WINDS IS POSTED FOR THIS REGION FOR
ALL OF WEEK-2. FORECAST ENSEMBLE MEAN WIND SPEEDS ARE ALSO ELEVATED ALONG THE
WEST COAST DURING ALL OF WEEK-2 WITH WIND SPEEDS OF 25-30MPH ALONG THE
IMMEDIATE COAST FROM MEDFORD, OR SOUTH TO POINT CONCEPTION IN CALIFORNIA.
ICE-BOUND RIVERS ARE BEGINNING TO BREAK UP IN THE NORTH SLOPE OF ALASKA. THERE
IS NO ASSOCIATED HAZARD POSTED AT THIS TIME BUT THIS SITUATION WILL BE CLOSELY
MONITORED IN THE COMING DAYS AND WEEKS AS CONDITIONS CAN QUICKLY CHANGE,
LEADING TO THE POTENTIAL FOR ICE JAMS, AUFEIS, AND ASSOCIATED FLOODING.
FORECASTER: RYAN BOLT
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