688
FXUS21 KWNC 231816
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MAY 23 2025
SYNOPSIS: MID-LEVEL HIGH PRESSURE IS FORECAST TO STRENGTHEN OVER THE WEST
LEADING TO ANOMALOUS WARMTH TO END MAY AND START JUNE. MULTIPLE MODELS HAVE
INCREASED SIGNALS COMPARED TO YESTERDAY FOR EXTREME HEAT ESPECIALLY ACROSS THE
CENTRAL VALLEY OF CALIFORNIA ON MAY 31, THUS A MODERATE RISK OF EXTREME HEAT IS
DESIGNATED FOR THIS DAY. A STATIONARY FRONT MAY BRING LOCALLY HEAVY RAINFALL
FROM THE CENTRAL TO SOUTHERN HIGH PLAINS SOUTHEASTWARD TO THE WESTERN GULF
COAST THROUGH EARLY WEEK-2, ALTHOUGH THERE IS SIGNIFICANT MODEL UNCERTAINTY
REGARDING THIS HAZARD. DURING THE FIRST WEEK OF JUNE, THERE IS AN INCREASING
RISK OF HEAVY RAINFALL ACROSS FLORIDA AND THE NORTHERN GULF COAST. A TIGHT
PRESSURE GRADIENT ALONG PARTS OF THE WEST COAST MAY BRING PERIODS OF HIGH WINDS
TO PARTS OF THE NORTHERN COAST OF CALIFORNIA.
HAZARDS
MODERATE RISK OF EXTREME HEAT FOR THE CENTRAL VALLEY OF CALIFORNIA, SAT, MAY 31.
SLIGHT RISK OF EXTREME HEAT FOR THE CENTRAL VALLEY OF CALIFORNIA, SAT-SUN, MAY
31-JUN 1.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE CENTRAL TO SOUTHERN GREAT
PLAINS, WESTERN GULF COAST, AND LOWER MISSISSIPPI VALLEY, SAT-MON, MAY 31-JUN 2.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE SOUTHEAST, WED-FRI, JUN 4-6.
SLIGHT RISK OF EPISODIC HIGH WINDS FOR COASTAL PORTIONS OF NORTHERN CALIFORNIA,
SAT-MON, MAY 31-JUN 2.
DETAILED SUMMARY
FOR MONDAY MAY 26 - FRIDAY MAY 30:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY MAY 31 - FRIDAY JUNE 06: MULTIPLE MODEL ENSEMBLE MEANS INDICATE
STRONGER MID-LEVEL RIDGING OVER THE WESTERN CONTIGUOUS U.S. (CONUS) COMPARED TO
YESTERDAY, AT THE ONSET OF WEEK-2. PEAK RIDGING IS ANTICIPATED FOR THE END OF
WEEK 1 (MAY 30) TO THE ONSET OF WEEK-2 (MAY 31), WITH NOTICEABLE WEAKENING BY
THE MIDDLE OF THE PERIOD. MODEL GUIDANCE AND TEMPERATURE TOOLS REFLECT THIS
CHANGE IN THE INCREASE IN HEAT SIGNALS. THE GEFS AND ECENS PROBABILISTIC
EXTREMES TOOLS (PETS) SHOW HIGHER PROBABILITIES OF MAXIMUM TEMPERATURES
EXCEEDING THE 85TH PERCENTILE CLIMATOLOGICALLY AND 100 DEG F. THUS A MODERATE
RISK OF EXTREME HEAT IS DESIGNATED ACROSS THE CENTRAL VALLEY OF CALIFORNIA FOR
MAY 31, WHERE THE GEFS AND ECENS INDICATE GREATER THAN 50% CHANCES OF EXCEEDING
THESE THRESHOLDS. RECENT DETERMINISTIC GUIDANCE SHOWS THE POTENTIAL FOR SOME
AREAS EXPERIENCING TEMPERATURES GREATER THAN 110 DEG F ACROSS SOME OF THE
EXTREME RISK AREAS. THE COMBINATION OF HIGH TEMPERATURES, LOW RELATIVE
HUMIDITY, AND DRYING VEGETATION MAY RESULT IN ELEVATED WILDFIRE RISK FOR THAT
PART OF CALIFORNIA.
SURFACE HIGH PRESSURE PREDICTED OVER THE NORTHEASTERN PACIFIC COMBINED WITH
ADJACENT SURFACE LOW PRESSURE ACROSS PARTS OF CALIFORNIA MAY RESULT IN A TIGHT
PRESSURE GRADIENT ALONG THE COAST OF CALIFORNIA. THIS PATTERN MAY SUPPORT
EPISODES OF HIGH WINDS IN THE AREA AT THE BEGINNING OF WEEK-2. A SLIGHT RISK OF
EPISODIC HIGH WINDS IS DESIGNATED FOR COASTAL PORTIONS OF NORTHERN CALIFORNIA,
WHERE PETS INDICATE AT LEAST A 30% CHANCE OF WIND SPEEDS EXCEEDING THE 85TH
PERCENTILE AND 35 MPH. ANTICIPATED DRY, HOT CONDITIONS COMBINED WITH GUSTY
WINDS COULD INCREASE WILDFIRE POTENTIAL ACROSS PORTIONS OF COASTAL CALIFORNIA.
A FRONT MAY LINGER ACROSS THE CENTRAL AND SOUTHERN HIGH PLAINS SOUTHEASTWARD TO
THE WESTERN GULF COAST AND LOWER MISSISSIPPI VALLEY AT THE BEGINNING OF THE
PERIOD. THIS FRONT IS EXPECTED TO BE A FOCUS FOR CONVECTION WITH LOCALLY HEAVY
RAINFALL. THERE IS MORE UNCERTAINTY IN TODAY’S MODELS COMPARED TO YESTERDAY
REGARDING ANTICIPATED RAINFALL AMOUNTS, WITH THE ECENS ESPECIALLY DECREASING
THE SIGNAL FOR ENHANCED AMOUNTS COMPARED TO YESTERDAY. AS OF 5AM PDT ON MAY 23,
THE NHC STATES THAT THERE IS A 60 PERCENT CHANCE OF TROPICAL CYCLONE (TC)
DEVELOPMENT ACROSS THE EAST PACIFIC DURING THE NEXT SEVEN DAYS. DESPITE
UNCERTAINTY AMONG MODELS REGARDING RAINFALL TOTALS, IF THIS TC FORMS AND TRACKS
MORE NORTHWARD, THEN ENHANCED MID-LEVEL MOISTURE MAY SHIFT NORTHWARD INTO THE
SOUTH-CENTRAL CONUS WHICH WAS ANOTHER FACTOR SUPPORTING AT LEAST A SLIGHT RISK
OF HEAVY PRECIPITATION FOR THIS REGION.
LOCALLY HEAVY RAINFALL COULD TRIGGER FLASH FLOODING OR RENEWED RIVER FLOODING
ESPECIALLY FOR NORTHEASTERN TEXAS AND WESTERN LOUISIANA, BUT UNCERTAINTY
REGARDING WHERE THE HEAVIEST RAINFALL MAY OCCUR DURING EARLY WEEK-2 PRECLUDES
DESIGNATING A FLOODING SHAPE ON THE MAP BUT WILL CONTINUE TO BE MONITORED.
MULTI-MODEL ENSEMBLE MEANS CONTINUE TO DEPICT A SURGE OF TROPICAL MOISTURE
SPREADING NORTHWARD FROM THE WESTERN CARIBBEAN TO FLORIDA AND THE NORTHERN GULF
COAST DURING THE FIRST WEEK OF JUNE. THE GEFS AND ECENS PETS CONTINUE TO SHOW
AT LEAST A 20% CHANCE OF 3-DAY RAINFALL AMOUNTS EXCEEDING THE 85TH PERCENTILE
(AND 1 INCH?)ACROSS FLORIDA, THE NORTHERN GULF COAST, AND COASTAL PLAIN OF THE
SOUTHEAST, SUPPORTING A SLIGHT RISK OF HEAVY PRECIPITATION FOR JUNE 4-6.
ACCORDING TO THE U.S. DROUGHT MONITOR, SEVERE TO EXTREME DROUGHT COVERS SOUTH
FLORIDA INCLUDING THE EVERGLADES. THE WETTER PATTERN FORECAST TO START JUNE
WOULD BE WELCOME DROUGHT RELIEF FOR THESE AREAS.
THE GEFS, ECENS, AND CMCE DEPICT AN AMPLIFIED 500-HPA TROUGH OVER ALASKA EARLY
IN WEEK-2 WHICH FAVORS BELOW-NORMAL TEMPERATURES AND ABOVE-NORMAL
PRECIPITATION. ALTHOUGH THE GEFS AND ECENS PETS INDICATE AT LEAST A 20% CHANCE
OF 3-DAY PRECIPITATION AMOUNTS EXCEEDING THE 85TH PERCENTILE ACROSS
SOUTHEASTERN ALASKA THROUGH JUNE 2, TOTALS ARE NOT ANTICIPATED TO REACH
HAZARDOUS CRITERIA.
FORECASTER: MELISSA OU
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