698
FXUS21 KWNC 271851
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT AUGUST 27 2025
SYNOPSIS: MULTIPLE MODELS CONTINUE TO INDICATE SURFACE LOW PRESSURE POTENTIALLY
FORMING IN THE WESTERN ATLANTIC AND MOVING ALONG PARTS OF THE EASTERN SEABOARD
EARLY IN THE PERIOD. THIS FEATURE COULD BRING HEAVY PRECIPITATION AND HIGH
WINDS TO OR NEAR THE EAST COAST, ALTHOUGH THE EVOLUTION OF ANY SYSTEM THAT DOES
DEVELOP IS HIGHLY UNCERTAIN. FARTHER SOUTH, A FEW WAVES OF LOW PRESSURE MAY
FORM ALONG A WAVERING FRONTAL SYSTEM FROM CENTRAL TEXAS THROUGH THE CENTRAL
GULF COAST AND THE SOUTHEAST, KEEPING A RISK OF SCATTERED HEAVY RAINFALL ACROSS
THESE REGIONS THROUGHOUT WEEK-2. IN THE SOUTHWEST, POTENTIAL TROPICAL CYCLONE
DEVELOPMENT WEST OF MEXICO COULD ENHANCE TROPICAL MOISTURE PUSHING INTO THE
SOUTHWEST, INCREASING THE POTENTIAL FOR EPISODES OF LOCALLY HEAVY PRECIPITATION
FOR THE REGION. MULTIPLE MODEL ENSEMBLE MEANS SHOW GREATER MID-LEVEL HIGH
PRESSURE ACROSS THE NORTHEAST PACIFIC AND PACIFIC NORTHWEST, LEADING TO A
SLIGHT RISK OF EXTREME HEAT AT THE BEGINNING OF WEEK-2 FOR PARTS OF WASHINGTON,
IDAHO, AND OREGON.
HAZARDS
SLIGHT RISK OF HIGH WINDS FOR COASTAL PORTIONS OF THE MID-ATLANTIC AND
NORTHEAST, THU-SAT, SEP 4-6.
SLIGHT RISK OF HEAVY PRECIPITATION FOR SOUTHERN FLORIDA AND COASTAL PORTIONS OF
THE MID-ATLANTIC AND SOUTHEAST, SAT-WED, SEP 6-10.
SLIGHT RISK OF HEAVY PRECIPITATION FOR THE GULF COAST, THU-WED, SEP 4-10.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE SOUTHWEST, THU-SAT, SEP 4-6.
SLIGHT RISK OF EXTREME HEAT FOR INTERIOR PORTIONS OF WASHINGTON, NORTHERN
OREGON, AND NORTHWESTERN IDAHO, THU-FRI, SEP 4-5.
SLIGHT RISK OF HIGH WINDS FOR PARTS OF EASTERN CALIFORNIA AND CENTRAL PARTS OF
WASHINGTON AND OREGON, THU-MON, SEP 4-8.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF THE EASTERN DAKOTAS,
UPPER MISSISSIPPI VALLEY, AND UPPER GREAT LAKES, THU-SAT, SEP 4-6.
DETAILED SUMMARY
FOR SATURDAY AUGUST 30 - WEDNESDAY SEPTEMBER 03:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY SEPTEMBER 04 - WEDNESDAY SEPTEMBER 10: MULTIPLE MODELS INDICATE
SURFACE LOW PRESSURE FORMING NEAR OR OVER THE NORTHEAST AT THE START OF WEEK-2.
THIS LOW AND ITS TRAILING FRONT MAY SUPPORT HIGH WINDS, RESULTING IN A SLIGHT
RISK OF HIGH WINDS FOR COASTAL PORTIONS OF THE MID-ATLANTIC AND NORTHEAST, SEP
4-6. THE ECENS AND CMCE PROBABILISTIC EXTREMES TOOLS (PETS) INDICATE AT LEAST A
20% CHANCE OF WIND SPEEDS EXCEEDING THE 85TH PERCENTILE CLIMATOLOGICALLY AND 25
MPH.
THERE IS CONTINUED SUPPORT IN MULTIPLE MODELS SHOWING THE POTENTIAL FORMATION
OF A SURFACE LOW IN THE WESTERN ATLANTIC. THIS LOW COMBINED WITH A PREDICTED
QUASI-STATIONARY FRONT EXTENDING FROM THE SOUTH ATLANTIC REGION WESTWARD ALONG
OR NEAR THE GULF COAST MAY SUPPORT PERIODS OF LOCALLY HEAVY PRECIPITATION
ACROSS FLORIDA AND THE GULF COAST. THERE IS STILL SIGNIFICANT UNCERTAINTY
REGARDING THE TIMING, LOCATION, AND QUANTITY OF PRECIPITATION, MAGNIFIED BY
MODEL INCONSISTENCIES REGARDING POTENTIAL SURFACE LOW PRESSURE DEVELOPMENT.
THEREFORE A GENERAL AREA IS HIGHLIGHTED WITH A SLIGHT RISK OF HEAVY
PRECIPITATION ACROSS COASTAL PORTIONS OF THE GULF COAST THROUGHOUT WEEK-2. A
SECONDARY AREA IS DESIGNATED WITH A SLIGHT RISK OF HEAVY PRECIPITATION FOR
SOUTHERN FLORIDA AND COASTAL PORTIONS OF THE MID-ATLANTIC AND SOUTHEAST, SEP
6-10, WHEN HEAVY RAINFALL IS MOST LIKELY. THE PETS SHOW THE POSSIBILITY OF
3-DAY RAINFALL ACCUMULATIONS EXCEEDING THE 85TH PERCENTILE AND ONE INCH DURING
THE PERIOD FOR THE HIGHLIGHTED RISK AREAS, FURTHER SUPPORTED BY DAILY GUIDANCE
IN THE UNCALIBRATED ENSEMBLE MEANS, AND RECENT DETERMINISTIC GUIDANCE.
AS OF 11AM PDT ON AUGUST 27, THE NATIONAL HURRICANE CENTER IS TRACKING 3 AREAS
FOR POSSIBLE TROPICAL CYCLONE FORMATION OVER THE EAST PACIFIC IN THE NEXT 7
DAYS IN ADDITION TO TROPICAL STORM JULIETTE CURRENTLY OFFSHORE OF SOUTHWESTERN
MEXICO. AT LEAST ONE OF THESE SYSTEMS MAY TRACK CLOSE TO THE BAJA PENINSULA.
DESPITE HIGH UNCERTAINTY OF THE TIMING AND POSSIBLE IMPACT OF ENHANCED MOISTURE
FROM POSSIBLE TROPICAL CYCLONES, A SLIGHT RISK OF LOCALLY HEAVY PRECIPITATION
IS HIGHLIGHTED FOR PARTS OF THE SOUTHWEST, SEP 4-6, PRIMARILY BASED ON GUIDANCE
FROM THE PETS.
ACROSS THE NORTHWEST, MULTIPLE MODEL ENSEMBLE MEANS INDICATE A STRONGER
MID-LEVEL RIDGE COMPARED TO YESTERDAY. THIS TRANSLATES TO GREATER SIGNALS FOR
THE POTENTIAL FOR EXTREME HEAT ACROSS PARTS OF THIS REGION. A SLIGHT RISK OF
EXTREME HEAT IS DESIGNATED FOR INTERIOR PORTIONS OF WASHINGTON, NORTHERN
OREGON, AND NORTHWESTERN IDAHO, SEP 4-5, WHERE PETS INDICATE AT LEAST A 20%
CHANCE OF MAXIMUM TEMPERATURES EXCEEDING THE 90TH PERCENTILE AND 90 DEG F. THE
NATIONAL BLEND OF MODELS SHOWS SOME AREAS HAVING THE POSSIBILITY OF NEAR RECORD
MINIMUM TEMPERATURES, ALTHOUGH ANTICIPATED TO REMAIN IN THE 60S DEG F.
POTENTIAL FOR THERMAL LOW PRESSURE FORMING ACROSS THE WEST COAST STATES WITH
ADJACENT SURFACE HIGH PRESSURE IN THE NORTHEAST PACIFIC MAY LEAD TO AN
INCREASED RISK OF HIGH WINDS. THEREFORE A SLIGHT RISK OF HIGH WINDS IS
DESIGNATED FOR PARTS OF EASTERN CALIFORNIA AND CENTRAL PARTS OF WASHINGTON AND
OREGON, SEP 4-8. ANTICIPATED HOT, DRY CONDITIONS MAY LEAD TO ENHANCED WILDFIRE
RISK ACROSS INTERIOR PORTIONS OF THE NORTHWEST AND NORTHERN CALIFORNIA.
AMPLIFIED MID-LEVEL TROUGHING IS PREDICTED DOWNSTREAM OF THE MID-LEVEL RIDGE,
OVER THE EASTERN HALF OF THE CONUS. MULTIPLE MODELS INDICATE MORE AMPLIFIED
TROUGHING COMPARED TO YESTERDAY, WHICH MAY LEAD TO ANOMALOUSLY COOL
TEMPERATURES ACROSS MUCH OF THE EAST, ESPECIALLY ACROSS CENTRAL PORTIONS. A
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES IS POSTED FOR PARTS OF THE
EASTERN DAKOTAS, UPPER MISSISSIPPI VALLEY AND UPPER GREAT LAKES, SEP 4-6.
MULTIPLE PETS SHOW AT LEAST A 20% CHANCE OF MINIMUM TEMPERATURES FALLING BELOW
THE 15TH PERCENTILE CLIMATOLOGICALLY AND BELOW 40 DEG F. THIS WOULD BE
CONSIDERED EARLY IN THE SEASON CLIMATOLOGICALLY FOR NEAR FREEZING TEMPERATURES
FOR THE REGION.
MID-LEVEL POSITIVE 500 HPA HEIGHT DEPARTURES ARE PREDICTED FOR THE MEAN WEEK-2
PATTERN FOR ALASKA, SUPPORTING ABOVE NORMAL TEMPERATURES FOR MUCH OF THE STATE,
EXCLUDING THE NORTHERN AREAS WHERE NEAR NORMAL TEMPERATURES ARE EXPECTED.
ALTHOUGH ANOMALOUSLY WARM TEMPERATURES ARE ANTICIPATED, ACTUAL TEMPERATURES ARE
NOT FORECAST TO REACH HAZARDOUS THRESHOLDS.
FORECASTER: MELISSA OU
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