926
FXUS21 KWNC 121806
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SEPTEMBER 12 2025
SYNOPSIS: MID-LEVEL HIGH PRESSURE ACROSS MUCH OF NORTH AMERICA DURING WEEK-2 IS
ANTICIPATED TO RESULT IN WIDESPREAD ABOVE-NORMAL TEMPERATURES FOR THE U.S.
EXTREME HEAT CONDITIONS ARE POSSIBLE ACROSS THE LOWER MISSISSIPPI AND TENNESSEE
VALLEYS, SOUTHEAST, AND SOUTHERN PLAINS AT THE BEGINNING OF THE PERIOD. THE
ABNORMALLY WARM TEMPERATURES, COMBINED WITH ANTECEDENT DRYNESS AND BELOW NORMAL
PRECIPITATION FAVORED DURING THE NEXT TWO WEEKS SUPPORT A RAPID ONSET DROUGHT
(ROD) RISK FOR MISSISSIPPI, ALABAMA, AND GEORGIA. A STALLED FRONTAL BOUNDARY
REMAINS FORECAST ACROSS THE SOUTHEASTERN U.S. BRINGING AN INCREASED LIKELIHOOD
FOR ENHANCED PRECIPITATION TO THE REGION WHICH COULD SUPPORT FLOODING ACROSS
PARTS OF THE FLORIDA PENINSULA. EARLY IN WEEK-2, TROPICAL MOISTURE ASSOCIATED
WITH AN EASTERN PACIFIC TROPICAL CYCLONE ENHANCES THE RISK FOR HEAVY
PRECIPITATION ACROSS PORTIONS OF THE SOUTHWEST. SURFACE LOW PRESSURE IS
FORECAST TO BRING INCREASED CHANCES OF HEAVY PRECIPITATION TO COASTAL PORTIONS
OF SOUTHEASTERN ALASKA.
HAZARDS
SLIGHT RISK OF EXTREME HEAT ACROSS LOWER MISSISSIPPI AND TENNESSEE VALLEYS,
SOUTHEAST, AND SOUTHERN PLAINS, SAT-SUN, SEP 20-21.
SLIGHT RISK OF HEAVY PRECIPITATION OVER THE FOUR CORNERS, SAT-MON, SEP 20-22.
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS MOST OF FLORIDA AND THE COASTAL
SOUTHEAST, SAT-MON, SEP 20-22.
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS COASTAL PORTIONS OF THE KENAI
PENINSULA AND THE NORTHERN PORTION OF SOUTHEAST ALASKA, SAT-SUN, SEP 20-21.
RAPID ONSET DROUGHT (ROD) RISK ACROSS MISSISSIPPI, ALABAMA, AND GEORGIA.
DETAILED SUMMARY
FOR MONDAY SEPTEMBER 15 - FRIDAY SEPTEMBER 19:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY SEPTEMBER 20 - FRIDAY SEPTEMBER 26: MEAN 500-HPA HEIGHT ANOMALY
FORECASTS FROM THE 0Z GEFS, ECENS, AND CMCE ENSEMBLES SHOW THE WEEK-2 PERIOD
STARTING OFF WITH AN AMPLIFIED RIDGE CENTER OVER EASTERN CANADA WHICH EXTENDS
SOUTHEASTWARD INTO MUCH OF THE NORTHERN TIER OF THE UPPER MIDWEST. A MID-LEVEL
TROUGH CONTINUES TO BE ANTICIPATED OVER THE EASTERN BERING SEA AND WESTERN
ALASKA FROM THE END OF WEEK-1 INTO WEEK-2, WITH SEVERAL SHALLOW, SHORTWAVE
TROUGHS OVER THE NORTHWESTERN AND NORTH-CENTRAL CONUS, AND OFF THE EAST COAST.
IN RESPONSE TO THE MID-LEVEL RIDGE AXIS EXTENDING FROM EASTERN CANADA INTO THE
UPPER MIDWEST NEXT WEEKEND, BOTH RAW AND CALIBRATED TEMPERATURE TOOLS CONTINUE
TO HIGHLIGHT ELEVATED CHANCES FOR WIDESPREAD COVERAGE OF ABOVE-NORMAL
TEMPERATURES OVER MOST OF THE CENTRAL AND EASTERN CONUS. A SLIGHT RISK OF
EXTREME HEAT IS MAINTAINED OVER LOWER MISSISSIPPI AND TENNESSEE VALLEYS,
SOUTHEAST, AND SOUTHERN PLAINS, SEP 20-21. THE RISK AREA IS EXTENDED SLIGHTLY
WESTWARD INTO MORE OF TEXAS ASSOCIATED WITH THE INCREASE IN HEAT SIGNAL IN THE
PROBABILISTIC EXTREME TOOLS (PETS) AND VARIOUS HEAT TOOLS. THE GEFS/ECENS PETS
INDICATE AT LEAST A 20% CHANCE OF MAXIMUM TEMPERATURES EXCEEDING THE 90TH
PERCENTILE CLIMATOLOGICALLY, REACHING THE MIDDLE TO UPPER 90S DEG F. THE
GREATEST DEW POINT TEMPERATURES (AT LEAST 70 DEG F) ARE FAVORED NEAR THE GULF
COAST, WHICH WOULD SUPPORT HIGHER HEAT INDEX VALUES. MULTIPLE HEAT TOOLS SHOW
EASTERN AND SOUTHERN PORTIONS OF TEXAS, AND THE GULF COAST HAVE THE POSSIBILITY
OF HEAT INDEX VALUES EXCEEDING TRIPLE DIGITS (DEG F).
THE COMBINATION OF 30 TO 60-DAY PRECIPITATION DEFICITS, ABOVE-NORMAL
TEMPERATURES AND BELOW-NORMAL PRECIPITATION FORECAST DURING THE NEXT TWO WEEKS
SUPPORTS A RAPID ONSET DROUGHT (ROD) RISK ACROSS MISSISSIPPI, ALABAMA, AND
GEORGIA. DRY VEGETATIVE FUELS IN THIS AREA TYPICALLY MEANS INCREASED RISK OF
WILDFIRES.
THERE ARE ENHANCED CHANCES FOR HEAVY PRECIPITATION OVER THREE AREAS OF THE
UNITED STATES DURING THIS HAZARDS PERIOD. THE FIRST AREA IS ALONG THE SOUTHEAST
COAST INCLUDING MOST OF FLORIDA, SEP 20-22. THIS IS RELATED TO A PREDICTED
STALLED FRONTAL BOUNDARY OVER THIS REGION, AND A WEAK MID-LEVEL TROUGH IN
ADDITION TO THE POSSIBILITY OF SURFACE LOWS FORMING OVER THE GULF OF AMERICA.
THE ECENS AND GEFS PETS INDICATE AT LEAST A 20% CHANCE OF 3-DAY ACCUMULATED
PRECIPITATION AMOUNTS IN EXCESS OF THE 85TH HISTORICAL PERCENTILE AND 1-INCH.
RECENT HEAVY RAINFALL ALONG WITH ANTICIPATED HEAVY RAINFALL DURING WEEKS 1 AND
2 ASSOCIATED WITH LINGERING FRONTS SUPPORTS THE ISSUANCE OF RISK FOR POSSIBLE
FLOODING ACROSS PARTS OF THE FLORIDA PENINSULA.
THE SECOND AREA OF FAVORED HEAVY PRECIPITATION IS CONTINUED AND EXPANDED ACROSS
THE FOUR CORNERS, SEP 20-22, WHERE TROPICAL MOISTURE MAY STREAM INTO THIS
REGION FROM THE GULF OF CALIFORNIA, IN RELATION TO A PASSING TROPICAL CYCLONE
OVER THE EASTERN PACIFIC. THE DESIGNATED HAZARD AREA IS PRIMARILY BASED ON
WHERE THE ECENS PET INDICATES AT LEAST A 40% CHANCE OF 3-DAY ACCUMULATED
RAINFALL TOTALS EXCEEDING THE 85TH PERCENTILE AND HALF AN INCH. THE INFLUX OF
TROPICAL MOISTURE FROM PASSING TROPICAL CYCLONES OVER THE EASTERN PACIFIC ALONG
WITH TRIGGERED GULF SURGES, ARE COMMONLY ACCOMPANIED BY FLASH AND/OR URBAN
FLOODING, AND THIS POSSIBILITY SHOULD BE MONITORED CLOSELY. THE THIRD AREA OF
FAVORED HEAVY PRECIPITATION IS ALONG THE SOUTHERN COAST OF ALASKA, FROM ABOUT
THE EASTERN KENAI PENINSULA EASTWARD TO INCLUDE APPROXIMATELY THE NORTHERN HALF
OF THE ALASKA PANHANDLE, SEP 20-21. WITH A MID-LEVEL TROUGH PREDICTED UPSTREAM
OVER THE EASTERN BERING SEA AND WESTERN ALASKA, AND SURFACE LOW PRESSURE NEAR
THE ALASKA PENINSULA, SOUTHERLY ONSHORE FLOW IS EXPECTED TO PREVAIL ACROSS THE
AFOREMENTIONED PORTION OF THE ALASKA COAST. THE GEFS AND ECENS PETS SUPPORT
3-DAY PRECIPITATION AMOUNTS EXCEEDING THE 85TH HISTORICAL PERCENTILE, AND AT
LEAST 2 INCHES (3 INCHES LOCALLY).
FORECASTER: MELISSA OU
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