625
FXUS21 KWNC 251830
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT AUGUST 25 2025
SYNOPSIS: A FRONTAL SYSTEM IS ANTICIPATED TO EXTEND FROM FLORIDA WESTWARD NEAR
THE GULF COAST AND THROUGH TEXAS, POTENTIALLY BECOMING A FOCUS FOR PERIODS OF
HEAVY PRECIPITATION ACROSS THESE AREAS AND THE LOWER MISSISSIPPI VALLEY FOR
MUCH OF WEEK-2. MEANWHILE, SURFACE LOW PRESSURE MAY FORM IN THE WESTERN
ATLANTIC AND MOVE THROUGH PARTS OF THE EASTERN SEABOARD EARLY IN THE PERIOD,
POSSIBLY SUPPORTING HEAVY PRECIPITATION AND HIGH WINDS ACROSS THIS REGION,
ALTHOUGH THE EVOLUTION OF ANY SYSTEM THAT DOES DEVELOP IS HIGHLY UNCERTAIN.
FARTHER WEST, POTENTIAL TROPICAL CYCLONE DEVELOPMENT WEST OF MEXICO COULD HELP
FUNNEL TROPICAL MOISTURE INTO THE SOUTHWEST, INCREASING THE POTENTIAL FOR
LOCALLY HEAVY PRECIPITATION THERE.
HAZARDS
SLIGHT RISK OF HIGH WINDS ALONG PORTIONS OF THE EAST COAST, TUE-WED, SEP 2-3.
SLIGHT RISK OF HEAVY PRECIPITATION ALONG PORTIONS OF THE EAST COAST, TUE-WED,
SEP 2-3.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PENINSULAR FLORIDA, TUE-MON, SEP 2-8.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF TEXAS AND THE LOWER
MISSISSIPPI VALLEY, WED-SUN, SEP 3-7.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE SOUTHWEST, WED-SUN, SEP
3-7.
DETAILED SUMMARY
FOR THURSDAY AUGUST 28 - MONDAY SEPTEMBER 01:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY SEPTEMBER 02 - MONDAY SEPTEMBER 08: WEEK-2 IS EXPECTED TO START
WITH A SURFACE HIGH PRESSURE SYSTEM ANCHORED NEAR THE GREAT LAKES OR NORTHEAST.
THIS IS EXPECTED TO KEEP RELATIVELY MILD AND DRY WEATHER OVER MOST OF THE
EASTERN HALF OF THE CONTIGUOUS STATES (CONUS). HOWEVER, A FRONTAL SYSTEM IS
PREDICTED TO FORM ALONG THE SOUTHERN AND EASTERN PERIPHERIES OF THIS SYSTEM,
AND BECOME QUASI-STATIONARY FROM THE FLORIDA PENINSULA WESTWARD ALONG OR NEAR
THE GULF COAST AND INTO TEXAS AND SOME ADJACENT AREAS. MOST MODELS FAVOR THIS
FRONT BECOMING A FOCUS FOR PERIODIC HEAVY PRECIPITATION, BUT THEY DIVERGE ON
THE EVOLUTION OF THE DETAILS. THE TIMING, LOCATION, AND QUANTITY OF HEAVY
PRECIPITATION ARE ALL IN QUESTION, MAGNIFIED BY MODEL INCONSISTENCIES REGARDING
POTENTIAL SURFACE LOW PRESSURE DEVELOPMENT. MOST TOOLS AT LEAST HINT AT THIS
POSSIBILITY, BUT THE STRENGTH, LOCATION, AND TIMING OF ANY SYSTEM THAT DOES
DEVELOP IS UNCERTAIN AT BEST. THE PROBABILISTIC EXTREMES TOOLS (PETS) DERIVED
FROM THE ENSEMBLES ALL SHOW RELATIVELY WEAK SIGNALS FOR HEAVY RAINFALL
POTENTIAL, WHICH MAKES SENSE GIVEN THE POTENTIAL BUT ALSO THE UNCERTAINTY. ALL
THINGS CONSIDERED, SLIGHT RISKS FOR HEAVY PRECIPITATION ARE POSTED FOR MUCH OF
WEEK-2 ACROSS PENINSULAR FLORIDA, THE LOWER MISSISSIPPI VALLEY, AND CENTRAL
THROUGH EASTERN TEXAS. IT SHOULD BE NOTED THAT ANY HEAVY PRECIPITATION THAT
DOES FALL WOULD PROBABLY BE EPISODIC AND NOT CONTINUE THROUGH THE ENTIRETY OF
THE RISK PERIOD. PRECIPITATION ASSOCIATED WITH THE FRONTAL SYSTEM WILL LIKELY
EXTEND FARTHER WEST AND NORTH INTO WESTERN TEXAS, EASTERN NEW MEXICO, AND THE
CENTRAL GREAT PLAINS EARLY WEEK-2, BUT AMOUNTS THERE SEEM UNLIKELY TO REACH
HAZARDS THRESHOLDS.
MEANWHILE, THE OPERATIONAL MODELS AND ENSEMBLE MEANS ALL HINT AT SOME SORT OF
ANOMALOUSLY LOW SURFACE PRESSURE OVER OR EAST OF THE SOUTH ATLANTIC COAST WITH
HIGHER-THAN-USUAL SURFACE PRESSURE OVER THE NORTHEASTERN CONUS. THE ENSEMBLE
MEANS SHOW A VERY WEAK SET-UP, INDICATIVE OF MEMBER-TO-MEMBER DIFFERENCES IN
THE HANDLING OF THIS SYSTEM, BUT BOTH THE 6Z DETERMINISTIC GFS AND THE 0Z
EUROPEAN COUNTERPART SHOW A FAIRLY STRONG LOW PRESSURE CENTER ALONG OR JUST
OFFSHORE FROM THE SOUTHEAST OR MID-ATLANTIC AREAS AT THE OUTSET OF WEEK-2. THE
12Z GFS IS LESS ROBUST WITH THIS SYSTEM, AND THE 0Z DETERMINISTIC CANADIAN EVEN
LESS SO, WITH THE SYSTEM REMAINING WELL OFFSHORE. DESPITE ALL THE UNCERTAINTY,
THERE ARE ENOUGH INDICATORS AT LEAST HINTING AT THIS GENERAL SCENARIO TO
JUSTIFY SLIGHT RISKS FOR BOTH HEAVY PRECIPITATION AND HIGH WINDS EARLY WEEK-2
ALONG PARTS OF THE EASTERN SEABOARD. IT’S POSSIBLE THAT THIS SYSTEM, IF IT
DEVELOPS, COULD ACQUIRE SOME TROPICAL CHARACTERISTICS, BUT THIS IS ALSO HIGHLY
UNCERTAIN AT THIS TIME.
AS OF 11AM PDT ON AUGUST 25, THE NATIONAL HURRICANE CENTER IS TRACKING TROPICAL
STORM JULIETTE SEVERAL HUNDRED MILES OFFSHORE OF SOUTHWESTERN MEXICO. JULIETTE
IS EXPECTED TO TRACK NORTH OR NORTHWESTWARD THROUGH LATE AUGUST BEFORE
WEAKENING, BUT SOME MEMBERS OF THE ECENS AND GEFS, IN ADDITION TO THE
DETERMINISTIC GFS, SHOW THE POSSIBILITY OF ONE OR TWO ADDITIONAL TROPICAL
CYCLONES FORMING IN THE EAST PACIFIC DURING THE ENSUING SEVEN TO TEN DAYS. AT
LEAST ONE OF THESE SYSTEMS MAY TRACK FARTHER EAST, CLOSE TO THE BAJA PENINSULA.
THIS TRACK WOULD INCREASE THE CHANCE FOR A SURGE OF ENHANCED LOW TO MID-LEVEL
MOISTURE NORTHWARD TO THE DESERT SOUTHWEST. THE CHANCES FOR HEAVY PRECIPITATION
ARE NOT ROBUST ACCORDING TO THE PETS, BUT THERE IS ENOUGH SUPPORT FROM THE
MODELS TO JUSTIFY A SLIGHT RISK OF HEAVY PRECIPITATION FOR MOST OF ARIZONA AND
SOME ADJACENT LOCATIONS FROM SEPTEMBER 3-7.
ALTHOUGH ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS THE PACIFIC NORTHWEST AND
NORTHERN INTERMOUNTAIN WEST, HAZARDOUS HEAT BECOMES MUCH LESS LIKELY BY EARLY
SEPTEMBER. THE MOST ANOMALOUS WARMTH IS EXPECTED ACROSS THE INTERIOR AREAS OF
WASHINGTON ALONG WITH SOUTHWESTERN IDAHO. THE ECENS-BASED PET SHOWS A GREATER
THAN 50 PERCENT CHANCE FOR HIGH TEMPERATURES IN THE TOP 15 PERCENT HISTORIC
OCCURRENCES ON SEP 3, BUT THE SAME TOOL SHOWS ONLY A SMALL AREA WHERE THERE IS
AT LEAST A 30% CHANCE OF TEMPERATURES EXCEEDING 95 DEG F OR HIGHER. THE HEAT
SIGNALS ARE WEAKER IN THE OTHER PETS. WITH VERY LITTLE INDICATION THAT ACTUAL
TEMPERATURES WILL EXCEED HAZARDS THRESHOLDS, NO AREAS ARE DESIGNATED WITH A
RISK OF EXTREME HEAT.
FROM THE MIDDLE TO LATTER PORTION OF WEEK-2, COOL HIGH PRESSURE MAY MOVE
SOUTHWARD FROM CANADA INTO NORTHERN SECTIONS OF THE INTERMOUNTAIN WEST,
ROCKIES, AND PLAINS. THIS COULD ESTABLISH A STRONG PRESSURE GRADIENT OVER AT
LEAST PART OF THESE REGIONS, ALTHOUGH THERE IS TOO MUCH MODEL VARIABILITY TO
JUSTIFY ANY WIND HAZARDS AT THIS TIME. SOME DETERMINISTIC MODEL RUNS,
ESPECIALLY THE 6Z GFS, SPIN UP A SURFACE LOW PRESSURE ALONG THE LEADING EDGE OF
THIS SYSTEM, WHICH COULD LEAD TO MODERATE TO HEAVY PRECIPITATION OVER OR NEAR
THE NORTH-CENTRAL CONUS DUE TO THE PETS INDICATING ONLY MARGINALLY ENHANCED
RISKS FOR HEAVY PRECIPITATION, AND GIVEN THE INCONSISTENCIES IN THE
DETERMINISTIC MODEL SOLUTIONS, A SLIGHT RISK FOR HEAVY PRECIPITATION IS NOT
DESIGNATED AT THIS TIME.
EARLY WEEK-2, SURFACE PRESSURES ARE FORECAST TO BE ANOMALOUSLY HIGH IN THE
NORTH PACIFIC, AND UNUSUALLY LOW OVER NORTHERN ALASKA AND THE ADJACENT ARCTIC
OCEAN. THIS IS LIKELY TO ESTABLISH ENHANCED WESTERLY OR SOUTHWESTERLY FLOW
ACROSS MOST OF THE STATE, ESPECIALLY ACROSS THE WESTERN AND SOUTHEASTERN
SECTIONS OF THE STATE. PRECIPITATION AMOUNTS AND WIND SPEEDS SEEM UNLIKELY TO
REACH HAZARDS THRESHOLDS AT THIS TIME, BUT THE SITUATION WILL BE CLOSELY
MONITORED. THE SET-UP MAY BE SIMILAR TO CURRENT CONDITIONS, WHICH HAS PROMPTED
FLOOD WATCHES AND WIND ADVISORIES OVER PARTS OF THE STATE. FAIRBANKS, AK
RECORDED 1.43 INCHES OF PRECIPITATION AUG 23-24, WHICH IS OVER 12% OF THEIR
ANNUAL NORMAL.
FORECASTER: RICH TINKER
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