401
FXUS21 KWNC 021837
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JUNE 02 2025
SYNOPSIS: MID-LEVEL HIGH PRESSURE IS FORECAST TO EXPAND INTO THE WESTERN
CONTIGUOUS U.S. (CONUS) LATE IN WEEK-1 INTO EARLY WEEK-2. AS A RESULT,
INCREASED CHANCES FOR EXTREME HEAT ARE FAVORED ACROSS LOW ELEVATION AREAS OF
THE GREAT BASIN AND CALIFORNIA CENTRAL VALLEY, BUT WITH THE STRONGEST HEAT
SIGNALS IN THE GUIDANCE BEING PRIOR TO THE START OF WEEK-2. TEMPERATURES ARE
FORECAST TO TREND DOWNWARD AT THE START OF WEEK-2, WITH MID-LEVEL LOW PRESSURE
DEPICTED ACROSS THE WEST BY THE MIDDLE OF THE PERIOD. FRONTAL ACTIVITY ACROSS
THE MIDWEST AND A POTENTIAL INCREASE IN TROPICAL MOISTURE ACROSS THE SOUTHEAST
SUPPORTS INCREASED CHANCES FOR HEAVY PRECIPITATION, BUT MODEL DIFFERENCES
RESULT IN ONLY A SLIGHT RISK BEING HIGHLIGHTED OVER A LARGE AREA. MODELS ARE IN
BETTER AGREEMENT REGARDING BROAD RIDGING DEVELOPING OVER THE EASTERN HALF OF
THE CONUS DURING THE SECOND HALF OF WEEK-2 FAVORING INCREASING EXTREME HEAT
RISK ACROSS PARTS OF THE MIDWEST.
HAZARDS
SLIGHT RISK OF EXTREME HEAT ACROSS THE CALIFORNIA CENTRAL VALLEY AND LOW
ELEVATION AREAS OF THE GREAT BASIN, TUE, JUN 10.
SLIGHT RISK OF EXTREME HEAT ACROSS PORTIONS OF SOUTHERN TEXAS AND THE LOWER
MISSISSIPPI VALLEY, TUE-WED, JUN 10-11.
SLIGHT RISK OF EXTREME HEAT ACROSS PORTIONS OF THE MIDWEST, FRI-MON, JUN 13-16.
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS PORTIONS OF THE GREAT PLAINS,
MISSISSIPPI, OHIO, AND TENNESSEE VALLEYS, GREAT LAKES, SOUTHERN APPALACHIANS,
AND SOUTHEAST, TUE-FRI, JUN 10-13.
DETAILED SUMMARY
FOR THURSDAY JUNE 05 - MONDAY JUNE 09:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY JUNE 10 - MONDAY JUNE 16: ANOMALOUS MID-LEVEL RIDGING IS FORECAST
TO DEVELOP ACROSS THE NORTHEAST PACIFIC DURING WEEK-1 AND EXPAND INTO THE
WESTERN CONUS. HOWEVER, THIS FEATURE IS PREDICTED TO BEGIN WEAKENING EARLY IN
WEEK-2 AND BECOME REPLACED BY TROUGHING BY THE MIDDLE OF THE PERIOD. AS A
RESULT, THE STRONGEST HEAT SIGNALS OCCUR DURING THE LATE WEEK-1 TIMEFRAME, WITH
LINGERING CHANCES OF HAZARDOUS HEAT CONTINUING INTO THE OUTSET OF WEEK-2. THE
ECENS AND GEFS PROBABILISTIC EXTREMES TOOLS (PETS) DEPICT AT LEAST A 40 PERCENT
CHANCE MAXIMUM TEMPERATURES EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE ON DAY-8
(JUN 10), WITH A DECREASING TREND THEREAFTER. MAXIMUM TEMPERATURES IN THE
UNCALIBRATED 0Z ECENS AND GEFS ARE PREDICTED TO BE IN THE 90S DEG F ACROSS LOW
ELEVATION AREAS OF THE GREAT BASIN, AND INTO THE LOW 100S DEG F OVER PARTS OF
THE CALIFORNIA CENTRAL VALLEY AT THE START OF THE PERIOD. GIVEN THE FORECAST
DECREASE IN THE MAGNITUDE OF POSITIVE HEIGHT ANOMALIES AND THE RESULTANT
DOWNWARD TEMPERATURE TREND, THE SLIGHT RISK FOR EXTREME HEAT IS VALID FOR DAY-8
(JUN 10) ONLY.
ENHANCED SUBTROPICAL RIDGING FAVORS HAZARDOUS HEAT ACROSS PORTIONS OF SOUTHERN
TEXAS AND THE LOWER MISSISSIPPI VALLEY. AS IN THE WEST, THE POSITIVE HEIGHT
ANOMALIES ARE STRONGER DURING THE LATE WEEK-1 PERIOD AND BEGIN TO DECREASE
HEADING INTO WEEK-2. THE GEFS AND ECENS PETS DEPICT AT LEAST A 20 PERCENT
CHANCE MAXIMUM TEMPERATURES EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE AND 100
DEG F ACROSS PARTS OF THE RIO GRANDE VALLEY. HIGHER DEW POINT VALUES ARE LIKELY
TO BUMP UP HEAT INDICES FURTHER EAST, WITH THE SKILL WEIGHTED HEAT TOOL
DEPICTING AT LEAST A 30 PERCENT CHANCE HEAT INDICES EXCEED 105 DEG F ACROSS THE
LOWER MISSISSIPPI VALLEY. AS A RESULT, A SLIGHT RISK OF EXTREME HEAT IS POSTED
ACROSS PORTIONS OF SOUTHERN TEXAS AND THE LOWER MISSISSIPPI VALLEY, JUN 10-11,
AND COINCIDES WITH MAJOR TO EXTREME HEAT RISK FROM THE NWS HEAT RISK GUIDANCE
AT THE END OF WEEK-1, AND SOME PERSISTENCE OF THIS HEAT INTO THE OUTSET OF
WEEK-2 DESPITE A WEAKENING MID-LEVEL RIDGE ALOFT.
AS WITH LAST WEEK, THE FORECAST ACROSS THE EAST IS UNCERTAIN EARLY IN WEEK-2
DUE TO A VARIABLE MID-LEVEL FLOW PATTERN AND THE ELEVATED POTENTIAL FOR
ENHANCED TROPICAL MOISTURE ACROSS THE SOUTHEASTERN U.S. THE PETS AND
UNCALIBRATED TOOLS CONTINUE TO SUPPORT A BROAD SLIGHT RISK FOR HEAVY
PRECIPITATION, JUN 10-13, ACROSS THE MISSISSIPPI, OHIO, AND TENNESSEE VALLEYS
TIED TO FRONTAL ACTIVITY AND OCCASIONAL CONVECTIVE PRECIPITATION, AND EXTENDING
THROUGH THE SOUTHEAST. THE 0Z GEFS CONTINUES TO BE MORE BULLISH WITH TROPICAL
MOISTURE COMPARED TO THE 0Z ECENS AND 0Z CMCE BUT ALL MODELS DEPICT ENHANCED
SOUTHERLY FLOW OUT OF THE GULF. LOCALIZED FLOODING IS A CONCERN FOR ANY AREAS
THAT DO RECEIVE HEAVY RAINFALL.
LATER IN WEEK-2, THE 0Z ECENS, GEFS, AND CMCE ARE IN VERY GOOD AGREEMENT
DEPICTING A BROAD 588-DM RIDGE DEVELOPING OVER THE EASTERN CONUS. THIS PATTERN
IS INDICATIVE OF A WIDESPREAD HEAT EVENT TAKING SHAPE BY MID JUNE, WITH SOME
EVIDENCE OF THIS IN THE ECENS PET WHICH DEPICTS AN EXPANDING AREA OF AT LEAST A
20 PERCENT CHANCE MAXIMUM TEMPERATURES EXCEED 90 DEG F ACROSS THE MIDWEST.
WHILE TEMPERATURES IN THE UNCALIBRATED ENSEMBLE GUIDANCE ARE GENERALLY NOT TOO
IMPRESSIVE YET, DEWPOINTS ARE FORECAST TO INCREASE WHICH WILL LEAD TO HIGHER
HEAT INDEX VALUES. FOR NOW A SLIGHT RISK OF EXTREME HEAT IS POSTED ACROSS
PORTIONS OF THE MIDWEST, JUN 13-16, BASED MAINLY ON PATTERN RECOGNITION AND
GOOD MODEL AGREEMENT.
ZONAL MID-LEVEL FLOW IS FORECAST ACROSS ALASKA, SITUATED IN BETWEEN RIDGING
NEAR THE ALEUTIANS AND TROUGHING OVER WESTERN CANADA. THE LARGEST POSITIVE
HEIGHT ANOMALIES ARE FAVORED OVER THE SOUTHWESTERN PORTIONS OF THE STATE,
DECREASING FURTHER NORTH AND EAST. PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION
ARE INCREASED ACROSS THE NORTHERN MAINLAND, BUT NO AREAS ARE EXPECTED TO REACH
HAZARDS THRESHOLDS. NEAR- TO BELOW-NORMAL TEMPERATURES ARE FORECAST ACROSS THE
MAINLAND AND SOUTHEAST ALASKA.
FORECASTER: THOMAS COLLOW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page