984
FXUS21 KWNC 301815
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SEPTEMBER 30 2024
SYNOPSIS: MID-LEVEL HIGH PRESSURE IS FORECAST OVER THE WESTERN TWO-THIRDS OF
THE CONTIGUOUS U.S. (CONUS), POTENTIALLY CONTINUING INCREASED RISK FOR
EXCESSIVE HEAT FROM THE END OF WEEK-1 INTO THE ONSET OF WEEK-2 OVER THE DESERT
SOUTHWEST. MID-LEVEL LOW PRESSURE OVER THE EAST COAST AND POTENTIAL TROPICAL
CYCLONE FORMATION OVER THE GULF OF MEXICO IN THE NEXT 7 DAYS MAY LEAD TO
INCREASED LIKELIHOOD OF HEAVY PRECIPITATION ACROSS PARTS OF THE SOUTHEAST U.S.
AT THE BEGINNING OF WEEK-2 THAT COULD EXACERBATE FLOOD CONDITIONS IN THE REGION.
HAZARDS
SLIGHT RISK OF EXCESSIVE HEAT OVER THE DESERT SOUTHWEST, TUE-WED, OCT 8-9.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE SOUTHEAST U.S., TUE-THU,
OCT 8-10.
POSSIBLE FLOODING FOR PARTS OF THE SOUTHEAST U.S.
RISK OF RAPID ONSET DROUGHT (ROD) ACROSS PORTIONS OF OKLAHOMA, TEXAS, WESTERN
ARKANSAS, AND WESTERN LOUISIANA.
DETAILED SUMMARY
FOR THURSDAY OCTOBER 03 - MONDAY OCTOBER 07:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY OCTOBER 08 - MONDAY OCTOBER 14: MID-LEVEL RIDGING ACROSS THE
WESTERN CONUS IS PREDICTED TO CONTINUE FROM THE END OF WEEK-1 INTO AND
THROUGHOUT WEEK-2, FAVORING ABOVE NORMAL TEMPERATURE ACROSS THE WESTERN
TWO-THIRDS OF THE CONUS. A SLIGHT RISK OF EXCESSIVE HEAT IS MAINTAINED FOR THE
DESERT SOUTHWEST, OCT 8-9, WHERE THE PROBABILISTIC EXTREMES TOOLS (PETS) SHOW
AT LEAST A 20% CHANCE OF MAXIMUM TEMPERATURES EXCEEDING THE 90TH PERCENTILE
CLIMATOLOGICALLY AND 105 DEG F WITH THE NATIONAL BLEND OF MODELS (NBM) SHOWING
POTENTIAL FOR NEAR RECORD-BREAKING TEMPERATURES. MULTIPLE MODELS INDICATE A
DECREASE IN THIS EXCESSIVE HEAT SIGNAL COVERAGE BY OCT 9.
THERE IS MULTI-MODEL DEPICTION OF MID-LEVEL TROUGHING OVER THE EASTERN CONUS
DURING WEEK-2. THIS PATTERN, COMBINED WITH THE NATIONAL HURRICANE CENTER (NHC)
INDICATING AT LEAST A 40% CHANCE OF TROPICAL CYCLONE FORMATION IN THE NEXT 7
DAYS, AS OF 2PM EDT, SUPPORTS A SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF
THE SOUTHEAST U.S. THE HIGHLIGHTED RISK AREA IS PRIMARILY BASED ON THE ECENS
PET, WHERE THERE IS AT LEAST A 20% CHANCE OF 3-DAY RAINFALL TOTAL EXCEEDING THE
85TH PERCENTILE AND ONE INCH (2 INCHES LOCALLY OVER THE FLORIDA PANHANDLE). THE
GEFS PET IS LESS SUPPORTIVE, WITH TOTALS PREDICTED TO EXCEED 0.75 INCHES AND
CONFINED TO COASTAL AREAS OF THE SOUTHEAST AND FLORIDA. A RISK OF POTENTIAL
FLOODING IS HIGHLIGHTED ACROSS THE SOUTHEAST DUE TO SATURATED SOILS,
ANTICIPATED WEEK-1 AND WEEK-2 PRECIPITATION, AND MULTIPLE GAUGES ALREADY IN
CURRENTLY EXPERIENCING MINOR TO MINOR FLOODING. SOME ECENS ENSEMBLE MEMBERS
SHOW THE POSSIBILITY OF THE MID-LEVEL TROUGH INTERACTING WITH THE TROPICAL
CYCLONE PREDICTED TO EJECT FROM FLORIDA LATE IN WEEK-1, THAT COULD LEAD TO
SURFACE LOW FORMATION NEAR THE MID-ATLANTIC COAST THAT COULD ALSO BRING HEAVY
RAIN AND HIGH WIND IMPACTS TO SOME AREAS. HOWEVER, AT THIS TIME THE GEFS
ENSEMBLE MEMBERS DO NOT CURRENTLY INDICATE THIS POTENTIAL. DUE TO HIGH
UNCERTAINTY ADDITIONAL ASSOCIATED HAZARDS ARE NOT DESIGNATED AT THIS TIME.
THE RAPID ONSET DROUGHT (ROD) AREA IS EXPANDED IN TODAY’S OUTLOOK OVER THE
SOUTHERN PLAINS, AND WESTERN ARKANSAS AND LOUISIANA BASED ON 30-DAY
PRECIPITATION DEFICITS, LOW SOIL MOISTURE, AND LITTLE PREDICTED RAINFALL DURING
THE NEXT TWO WEEKS. WITH ALL THE UNCERTAINTY REGARDING FUTURE TROPICAL STORM
DEVELOPMENT AND TRACKS, THE EXTENDED ROD REGION WAS KEPT AWAY FROM THE TEXAS
COAST.
MID-LEVEL TROUGHING IS PREDICTED OVER MUCH OF ALASKA, SUPPORTING SURFACE LOW
FORMATION OVER THE GULF OF ALASKA THAT COULD SUPPORT ENHANCED PRECIPITATION AND
WIND SPEEDS, EXTENDING FROM THE KENAI PENINSULA TO THE SOUTHEASTERN MAINLAND.
THE PETS INDICATE AT LEAST A 20% CHANCE OF 3-DAY PRECIPITATION EXCEEDING THE
85TH PERCENTILE AND 2 INCHES, WITH THE ECENS PET SHOWING SOME LOCALIZED AREAS
EXCEEDING 3 INCHES. ALTHOUGH CONSIDERED ANOMALOUSLY WET, PREDICTED THRESHOLDS
DO NOT REACH HAZARDOUS CRITERIA PRECLUDING ASSOCIATED HAZARDS FROM BEING
HIGHLIGHTED AT THIS TIME.
FORECASTER: MELISSA OU
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