867
FXUS21 KWNC 031831
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT OCTOBER 03 2025
SYNOPSIS: PRIOR TO WEEK-2, A TROPICAL CYCLONE (TC) IS LIKELY TO DEVELOP
OFFSHORE OF SOUTHWESTERN MEXICO WITH A SUBSEQUENT TRACK NORTHWESTWARD NEAR THE
BAJA PENINSULA. DUE TO THIS POTENTIAL TC IN THE EAST PACIFIC, THERE IS AN
INCREASED CHANCE OF HEAVY RAINFALL ACROSS THE FOUR CORNERS REGION AND DESERT
SOUTHWEST THROUGH THE MIDDLE OF THE FORECAST PERIOD. A RAPID ONSET DROUGHT RISK
REMAINS FOR PARTS OF THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY WHERE
ABOVE-NORMAL TEMPERATURES AND LIMITED PRECIPITATION IS FORECAST OVER THE NEXT 2
WEEKS. OVER ALASKA, A STRONG LOW PRESSURE SYSTEM MAY BRING HIGH WINDS TO
PORTIONS OF THE BERING SEA AND CHUKCHI SEA COASTS.
HAZARDS
MODERATE RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE DESERT SOUTHWEST AND
SOUTHERN GREAT BASIN, SAT-MON, OCT 11-13.
SLIGHT RISK OF HEAVY PRECIPITATION FOR MUCH OF THE DESERT SOUTHWEST AS WELL AS
PORTIONS OF THE SOUTHERN AND CENTRAL ROCKIES AND SOUTHERN GREAT BASIN, SAT-WED,
OCT 11-15.
SLIGHT RISK OF HIGH WINDS FOR COASTAL AREAS OF WESTERN MAINLAND ALASKA, THE
ALASKA PENINSULA, AND THE ALEUTIANS, SAT-SUN, OCT 11-12.
FLOODING POSSIBLE ACROSS PORTIONS OF THE SOUTHWEST AND FOUR CORNERS REGION.
RAPID ONSET DROUGHT (ROD) POSSIBLE FOR PARTS OF TEXAS AND LOUISIANA.
DETAILED SUMMARY
FOR MONDAY OCTOBER 06 - FRIDAY OCTOBER 10:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY OCTOBER 11 - FRIDAY OCTOBER 17: AS OF 11AM PDT ON OCTOBER 3, THE
NATIONAL HURRICANE CENTER (NHC) IS CONTINUING TO MONITOR A BROAD AREA OF
DISTURBED WEATHER OFFSHORE OF SOUTHWESTERN MEXICO AND STATES THAT THERE IS A 90
PERCENT CHANCE OF A TC FORMING IN THIS AREA DURING THE NEXT 7 DAYS. MODEL
GUIDANCE REMAINS CONSISTENT INDICATING THIS POTENTIAL TC TRACKING NORTHWESTWARD
NEAR THE BAJA PENINSULA. THE NHC IS ALSO MONITORING A SECOND DISTURBANCE SOUTH
OF THE GULF OF TEHUANTEPEC, WHICH CURRENTLY HAS A LOWER CHANCE OF FORMING INTO
A TC (30% IN THE NEXT 7 DAYS) WHILE MOVING NORTHWESTWARD PARALLEL TO THE
MEXICAN COAST. TODAY’S MODEL SOLUTIONS FROM THE 0Z ECMWF AND GEFS ARE QUITE
BULLISH WITH RESPECT TO TC FORMATION ASSOCIATED WITH THE SECOND DISTURBANCE IN
WEEK-2, AS WELL AS TRACKING BOTH DISTURBANCES TOWARD THE GULF OF CALIFORNIA.
THIS SCENARIO WOULD TRANSPORT COPIOUS AMOUNTS OF TROPICAL MOISTURE INTO THE
DESERT SOUTHWEST AND GENERATE POTENTIALLY HAZARDOUS HEAVY PRECIPITATION. THIS
IS WELL-SUPPORTED BY THE ECMWF AND GEFS PROBABILISTIC EXTREMES TOOLS (PETS)
WHICH BOTH INDICATE AT LEAST A 40% CHANCE OF 3-DAY TOTAL PRECIPITATION TO
EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE AND AT LEAST 1 INCH EARLY IN WEEK-2.
THIS SIGNAL DROPS OFF AS THE FORECAST PERIOD PROGRESSES BUT STILL INDICATES AT
LEAST A 20% CHANCE OF 3-DAY PRECIPITATION EXCEEDING HAZARDOUS THRESHOLDS
THROUGH THE MIDDLE OF THE WEEK EXTENDING FURTHER NORTH INTO THE GREAT BASIN AND
ROCKY MOUNTAINS. A MODERATE RISK OF HEAVY PRECIPITATION IS POSTED FOR MUCH OF
CENTRAL AND NORTHERN ARIZONA AS WELL AS ADJACENT AREAS OF UTAH, COLORADO, AND
NEW MEXICO FOR OCT. 11-13, AS WELL AS A SLIGHT RISK OF HEAVY PRECIPITATION
EXTENDING FURTHER INLAND TO COVER THE WESTERN SLOPE OF THE SOUTHERN AND CENTRAL
ROCKIES AS WELL AS MUCH OF THE WASATCH AND UINTA MOUNTAINS, FOR OCT 11-15. A
FLOODING POSSIBLE HAZARD IS ALSO POSTED FOR PORTIONS OF THE SOUTHWEST AND FOUR
CORNERS REGION ASSOCIATED WITH THE MODERATE RISK OF HEAVY PRECIPITATION AND THE
POTENTIAL FOR LOCALIZED FLOODING AND FLASH FLOODING, PARTICULARLY IN CANYONS
AND CREEKS WHERE TOPOGRAPHY CAN FOCUS RUNOFF RESULTING IN QUICKLY RISING WATER
LEVELS.
AN AMPLIFIED 500-HPA TROUGH OVER THE BERING SEA IS FORECAST TO RESULT IN A DEEP
SURFACE LOW PRESSURE SYSTEM AFFECTING WESTERN MAINLAND ALASKA, THE ALASKA
PENINSULA, AND ALEUTIANS DURING EARLY TO MID-OCTOBER. BASED ON PATTERN
RECOGNITION WITH GOOD MODEL AGREEMENT ON MODERATELY STRONG LOW PRESSURE SYSTEMS
AND SUPPORT FROM THE GEFS AND ECENS PETS, A SLIGHT RISK OF EPISODIC HIGH WINDS
IS POSTED FOR WESTERN MAINLAND ALASKA ALONG THE BERING AND CHUKCHI SEA COASTS
ALONG WITH THE ALEUTIANS AND ALASKA PENINSULA. THIS WIND HAZARD IS VALID OVER
THE FIRST TWO DAYS OF THE PERIOD (OCTOBER 11-12), AFTER WHICH SURFACE PRESSURE
GRADIENTS ARE FAVORED TO EASE.
ACROSS PORTIONS OF TEXAS, LOUISIANA, AND CENTRAL MISSISSIPPI, 30-DAY
PRECIPITATION DEFICITS RANGE FROM 2 TO 5 INCHES. THIS ANTECEDENT DRYNESS ALONG
WITH LITTLE TO NO PRECIPITATION ANTICIPATED DURING THE NEXT WEEK TO TEN DAYS
AND INCREASED LIKELIHOOD OF ABOVE-NORMAL TEMPERATURES (HIGHS IN THE MID 80S TO
LOW 90S) RESULTS IN A RAPID ONSET DROUGHT RISK FOR PORTIONS OF SOUTHEASTERN
TEXAS, MUCH OF LOUISIANA, AND CENTRAL MISSISSIPPI.
FORECASTER: DANNY BARANDIARAN
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