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FXUS21 KWNC 141806
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JUNE 14 2023
SYNOPSIS: MID-LEVEL HIGH PRESSURE IS PREDICTED TO PERSIST FROM WEEK-1
THROUGHOUT WEEK-2 ACROSS THE SOUTH-CENTRAL CONTIGUOUS U.S. (CONUS), SUPPORTING
CONTINUED INCREASED CHANCES FOR EXCESSIVE HEAT ACROSS PARTS OF THE REGION
THROUGHOUT MUCH OF THE PERIOD. THERE IS A POTENTIAL FOR SOME AREAS TO
EXPERIENCE NEAR RECORD TEMPERATURES IN THE TRIPLE DIGITS, ESPECIALLY AT THE
BEGINNING OF WEEK-2, ACROSS THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY.
SNOWMELT SEASON CONTINUES FOR PORTIONS OF THE WEST AFTER EXCEPTIONAL WINTER
ACCUMULATIONS, LEADING TO THE CONTINUED POTENTIAL FOR FLOODING. SOME AREAS ARE
ANTICIPATED TO HAVE SOME IMPROVEMENT IN FLOOD CONDITIONS DUE TO DECREASING
SNOWPACK.
HAZARDS
MODERATE RISK OF EXCESSIVE HEAT ACROSS PARTS OF THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI VALLEY, THU-SAT, JUN 22-24.
SLIGHT RISK OF EXCESSIVE HEAT ACROSS PARTS OF THE SOUTH-CENTRAL CONUS, LOWER
MISSISSIPPI VALLEY, AND MISSOURI, THU-WED, JUN 22-28.
POSSIBLE FLOODING FOR PORTIONS OF CALIFORNIA, NEVADA, UTAH, WYOMING, AND IDAHO.
POSSIBLE FLOODING ALONG PORTIONS OF THE JAMES RIVER IN SOUTH DAKOTA.
RAPID ONSET DROUGHT RISK ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY.
DETAILED SUMMARY
FOR SATURDAY JUNE 17 - WEDNESDAY JUNE 21:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY JUNE 22 - WEDNESDAY JUNE 28: THE PRIMARY HAZARDS CONCERN IS THE
CONTINUED INCREASED RISK FOR EXCESSIVE HEAT ACROSS THE SOUTH-CENTRAL CONUS AND
LOWER MISSISSIPPI VALLEY DURING WEEK-2. THE 0Z GEFS AND ECMWF ENSEMBLE MEANS
ARE FAIRLY SIMILAR AT THE BEGINNING OF THE PERIOD COMPARED TO YESTERDAY
REGARDING THE STRENGTH AND ORIENTATION OF THE MID-LEVEL RIDGE ACROSS THE
SOUTH-CENTRAL CONUS. BY THE MIDDLE OF THE PERIOD (DAY 10/JUN 24), THESE
ENSEMBLE MEANS SHOW WEAKER POSITIVE MID-LEVEL HEIGHTS COMPARED TO YESTERDAY,
SHIFTING WESTWARD WITH TIME. THIS GRADUAL RIDGE RETROGRESSION MAY PROVIDE SOME
RELIEF FROM THE EXCESSIVE HEAT FOR EASTERN TEXAS AND LOUISIANA BY MID WEEK-2.
THE MODERATE RISK IS CONTINUED ACROSS PARTS OF THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI VALLEY, JUN 22-24, WHERE CALIBRATED HEAT INDEX TOOLS INDICATE AT
LEAST A 40% CHANCE OF EXCEEDING THE 90TH PERCENTILE CLIMATOLOGICALLY. A BROADER
SLIGHT RISK AREA IS HIGHLIGHTED ACROSS PARTS OF THE SOUTH-CENTRAL CONUS, LOWER
MISSISSIPPI VALLEY, AND MISSOURI, THROUGHOUT WEEK-2, WHERE THESE TOOLS SHOW AT
LEAST A 20% CHANCE OF HEAT INDEX VALUES EXCEEDING THE 90TH PERCENTILE. THE
NATIONAL BLEND OF MODELS (NBM) CONTINUES TO INDICATE THE POTENTIAL FOR NEAR
RECORD BREAKING TEMPERATURES (GREATER THAN 110 DEG F ACROSS PARTS OF TEXAS AND
UPPER 90S DEG F FOR LOUISIANA) FOR DAYS 8-9 (JUN 22-23). BY DAY 10 (JUN 24),
THE NBM INDICATES RECORD BREAKING TEMPERATURES BEING LIMITED TO SOUTHERN TEXAS.
GIVEN THE EXCESSIVE HEAT FORECAST ALONG WITH ANTECEDENT DRY CONDITIONS, RAPID
ONSET DROUGHT (ROD) RISK REMAINS ELEVATED ACROSS PORTIONS OF THE LOWER
MISSISSIPPI VALLEY WHERE SOIL MOISTURE VALUES HAVE DROPPED BELOW THE 30TH
CLIMATOLOGICAL PERCENTILE IN SOME AREAS. ADDITIONALLY, ANTICIPATED HOT AND DRY
CONDITIONS MAY ELEVATE WILDFIRE RISK ACROSS PARTS OF TEXAS AND LOUISIANA,
ESPECIALLY WHERE THE NATIONAL INTERAGENCY FIRE CENTER (NIFC) INDICATES MODERATE
TO HIGH RISK OF SIGNIFICANT FIRE POTENTIAL BY THE END OF WEEK-1.
MULTIPLE ENSEMBLE MEANS CONTINUED TO INDICATE SOME POSITIVE MID-LEVEL HEIGHT
ANOMALIES ACROSS PORTIONS OF THE UPPER MIDWEST AND NORTHEAST, BUT WEAKER
COMPARED TO YESTERDAY AND BEING LIMITED TO NEW ENGLAND BY DAY 10 (JUN 24).
TEMPERATURES IN THESE AREAS ARE ANTICIPATED TO REMAIN BELOW 90 DEG F,
PRECLUDING A HAZARD FROM BEING POSTED FOR THIS REGION.
THE CANADIAN AND ECMWF PROBABILISTIC EXTREMES TOOL (PET) CONTINUE TO INDICATE
AT LEAST A 20% CHANCE OF 3-DAY RAINFALL EXCEEDING THE 85TH PERCENTILE, WHEREAS
THE GEFS PET KEEPS THIS FEATURE TO ISOLATED PARTS OF COASTAL NORTH CAROLINA.
THE DETERMINISTIC AND ENSEMBLE GFS SOLUTIONS FAVOR SURFACE LOW FORMATION
ORIGINATING NEAR THE CAROLINA COAST OR TRACKING TO THE REGION FROM NEAR CUBA,
WHERE THE ECMWF COUNTERPARTS INITIATE THIS LOW OVER THE SOUTHEASTERN CONUS.
THERE CONTINUES TO BE TOO MUCH UNCERTAINTY AT THIS TIME REGARDING THE DETAILS
OF THIS FEATURE TO DESIGNATE A RELATED HEAVY PRECIPITATION HAZARD AT THIS TIME.
SNOWMELT SEASON CONTINUES ACROSS PORTIONS OF THE WESTERN CONUS AFTER
ACCUMULATING A VERY LARGE AND IN SOME CASES RECORD-BREAKING SNOWPACK, INDUCING
RIVER FLOODING ESPECIALLY ACROSS HIGHER ELEVATIONS FOR SOME AREAS IN THE WEST.
AS SNOWMELT CONTINUES IN PARTS OF THE SIERRA NEVADA, GREAT BASIN, AND NORTHERN
ROCKIES, FLOODING MAY CONTINUE TO OCCUR ALONG SOME RIVERS AND CREEKS, AND IN
AREAS ADJACENT TO THE HIGHER ELEVATIONS. IMPROVEMENTS IN FLOOD CONDITIONS ARE
ANTICIPATED BY WEEK-2 ACROSS PARTS OF THE WEST BASED ON DECREASING SNOWPACK.
POSSIBLE FLOODING ALSO REMAINS ACROSS LOCALIZED NORTHERN PARTS OF THE JAMES
RIVER IN SOUTH DAKOTA. MULTIPLE GAUGES ARE ANTICIPATED TO HAVE IMPROVEMENT IN
FLOOD LEVELS BY AND DURING WEEK-2.
WEAK POSITIVE MID-LEVEL HEIGHT DEPARTURES CONTINUE TO BE FAVORED ACROSS MOST OF
ALASKA (EXCLUDING WESTERN ALEUTIANS), SUPPORTING NEAR TO ABOVE NORMAL
TEMPERATURES ACROSS MUCH OF THE NORTHERN AND EASTERN MAINLAND AND SOUTHEAST
ALASKA, WITH BELOW NORMAL TEMPERATURES FORECAST ELSEWHERE. A RELATIVELY
INACTIVE STORM PATTERN IS ANTICIPATED FOR ALASKA PRECLUDING ANY HAZARDS
DESIGNATED FOR THE STATE.
FORECASTER: MELISSA OU
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