995
FXUS21 KWNC 151816
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MAY 15 2024
SYNOPSIS: MID-LEVEL HIGH PRESSURE IS FORECAST ACROSS THE SOUTHERN TIER OF THE
CONTIGUOUS U.S. (CONUS) DURING WEEK-2. THIS FAVORS INCREASED CHANCES FOR
ANOMALOUSLY WARM TEMPERATURES, AND EXCESSIVE HEAT CONDITIONS POSSIBLY AFFECTING
PARTS OF THE SOUTHERN PLAINS, LOWER MISSISSIPPI VALLEY, AND THE FLORIDA
PENINSULA. MID-LEVEL LOW PRESSURE PREDICTED ACROSS THE NORTHWESTERN AND
NORTH-CENTRAL CONUS EARLY IN THE PERIOD COULD LEAD TO A SHORTWAVE DISTURBANCE
TRAVERSING THE CONUS FAVORING INCREASED CHANCES FOR HEAVY PRECIPITATION ACROSS
PORTIONS OF THE CENTRAL AND EAST-CENTRAL CONUS, ALONG WITH ELEVATED WIND SPEEDS
ACROSS THE FOUR CORNERS AND HIGH PLAINS AS THIS POTENTIAL SYSTEM EJECTS OUT OF
THE ROCKIES EARLY IN WEEK-2.
HAZARDS
MODERATE RISK FOR EXCESSIVE HEAT ACROSS SOUTHERN TEXAS AND THE SOUTHERN FLORIDA
PENINSULA, THU-SAT, MAY 23-25.
SLIGHT RISK FOR EXCESSIVE HEAT ACROSS PORTIONS OF THE SOUTHERN PLAINS, LOWER
MISSISSIPPI VALLEY, AND THE FLORIDA PENINSULA, THU-WED, MAY 23-29.
SLIGHT RISK FOR HEAVY PRECIPITATION ACROSS PORTIONS OF THE GREAT PLAINS,
MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS, GREAT LAKES, AND SOUTHEAST, THU-SAT,
MAY 23-25.
SLIGHT RISK FOR HIGH WINDS ACROSS PARTS OF THE FOUR CORNERS AND CENTRAL AND
SOUTHERN HIGH PLAINS, THU-FRI, MAY 23-24.
RAPID ONSET DROUGHT RISK ACROSS THE SOUTHERN FLORIDA PENINSULA.
DETAILED SUMMARY
FOR SATURDAY MAY 18 - WEDNESDAY MAY 22:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY MAY 23 - WEDNESDAY MAY 29: SUBTROPICAL RIDGING IS FORECAST ACROSS
PORTIONS OF THE SOUTH-CENTRAL CONUS DURING THE WEEK-2 PERIOD. THIS FAVORS
INCREASING CHANCES FOR ANOMALOUSLY WARM TEMPERATURES STRETCHING FROM THE
CENTRAL AND SOUTHERN PLAINS EASTWARD TO THE SOUTHERN MID-ATLANTIC AND SOUTHEAST
COASTS. GIVEN THE TIME OF YEAR, MANY AREAS AWAY FROM THE GULF COAST ARE NOT
EXPECTED TO HAVE TEMPERATURES REACH EXCESSIVE HEAT CRITERIA. STRONGER SIGNALS
FOR EXCESSIVE HEAT ARE ACROSS PORTIONS OF TEXAS AND THE LOWER MISSISSIPPI
VALLEY WHERE THE GEFS AND ECMWF PROBABILISTIC EXTREMES TOOLS (PETS) DEPICT AT
LEAST A 20 PERCENT CHANCE FOR MAXIMUM TEMPERATURES EXCEEDING THE 85TH
CLIMATOLOGICAL PERCENTILE AND 90 DEG F. THE GEFS PET CONTINUES TO SHOW
PROBABILITIES ABOVE 40 PERCENT ACROSS PORTIONS OF SOUTHERN AND SOUTHWESTERN
TEXAS, ALTHOUGH THE ECMWF PET GENERALLY DEPICTS LOWER PROBABILITIES EARLY IN
WEEK-2, BUT INCREASES THEM ABOVE 40 PERCENT DURING THE MIDDLE OF THE PERIOD.
THE NATIONAL BLEND OF MODELS (NBM) DEPICTS RECORD DAILY MAXIMUM TEMPERATURES
ACROSS PARTS OF SOUTH TEXAS (UP TO 105 DEG F) EARLY IN WEEK-2. GIVEN THE
SUPPORT FROM THE NBM AND THE CALIBRATED GEFS HEAT RISK GUIDANCE, WHICH
INDICATES AT LEAST A 30 PERCENT CHANCE HEAT INDICES EXCEED THE 95TH
CLIMATOLOGICAL PERCENTILE OR 110 DEG F ACROSS PARTS OF SOUTHERN TEXAS, THE
MODERATE RISK FOR EXCESSIVE HEAT IS MAINTAINED FOR MAY 23-25. A BROADER SLIGHT
RISK CONTINUES ACROSS MUCH OF THE REMAINDER OF TEXAS (EXCLUDING THE PANHANDLE),
SOUTHEASTERN NEW MEXICO, AND THE LOWER MISSISSIPPI VALLEY FOR ALL OF WEEK-2.
FOR THE WESTERN SIDE OF THE SLIGHT RISK AREA, HEAT IS LIKELY TO BE TEMPERATURE
DRIVEN, BUT HIGHER DEW POINTS FAVORED ACROSS EASTERN TEXAS AND THE LOWER
MISSISSIPPI VALLEY MAY PUSH HEAT INDICES ABOVE 105 DEG F DESPITE THE RELATIVELY
LOWER TEMPERATURES COMPARED TO THOSE FURTHER WEST.
THE ECMWF PET REMAINS VERY ROBUST BRINGING IN HOT TEMPERATURES ACROSS THE
FLORIDA PENINSULA, WITH PROBABILITIES GREATER THAN 60 PERCENT FOR MAXIMUM
TEMPERATURES EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE ACROSS PARTS OF SOUTH
FLORIDA. THERE HAS ALSO BEEN AN UPTICK IN THE SIGNAL IN THE GEFS PET COMPARED
TO YESTERDAY, WITH THESE SAME AREAS HAVING PROBABILITIES ABOVE 40 PERCENT. THE
NBM ALSO DEPICTS SOME PARTS OF THE PENINSULA REACHING THE MID-90S DEG F, AND
COMBINED WITH DEW POINTS ABOVE 70 DEG F, WOULD RESULT IN HEAT INDICES POSSIBLY
GREATER THAN 105 DEG F. GIVEN THESE INCREASED SIGNALS, THE SLIGHT RISK FOR
EXCESSIVE HEAT IS EXPANDED NORTHWARD THROUGH MOST OF THE FLORIDA PENINSULA FOR
ALL OF WEEK-2, AND A MODERATE RISK IS NOW HIGHLIGHTED ACROSS THE SOUTHERN
FLORIDA PENINSULA FROM MAY 23-25. DECREASING SOIL MOISTURE AND A WARM AND DRY
PATTERN PREDICTED IN WEEK-2 LEAD TO INCREASED RAPID ONSET DROUGHT RISK ACROSS
PARTS OF SOUTH FLORIDA.
TROUGHING FORECAST ACROSS THE NORTHWESTERN AND NORTH-CENTRAL CONUS FAVORS
BELOW-NORMAL TEMPERATURES ACROSS MUCH OF THE WEST, EXTENDING INTO PARTS OF THE
NORTHERN AND CENTRAL PLAINS, UPPER AND MIDDLE MISSISSIPPI VALLEY, AND GREAT
LAKES. THE 0Z ECMWF ENSEMBLE IS MORE ROBUST WITH THIS TROUGHING COMPARED TO THE
GEFS, AND AS A RESULT DEPICTS A MORE AMPLIFIED SHORTWAVE DISTURBANCE MOVING
ACROSS THE CONUS EARLY IN WEEK-2. GIVEN THE POTENTIAL FOR SUCH A SYSTEM TO
EJECT OUT OF THE ROCKIES, A SLIGHT RISK OF HIGH WINDS IS POSTED ACROSS PARTS OF
THE FOUR CORNERS AND CENTRAL AND SOUTHERN HIGH PLAINS FOR MAY 23-24.
DETERMINISTIC RUNS FROM THE 0Z GFS AND ECMWF DEPICT WIND SPEEDS EXCEEDING
25-MPH OVER THESE AREAS, AND COMBINED WITH THE ANOMALOUSLY DRY CONDITIONS,
COULD ENHANCE THE WILDFIRE RISK OVER THE REGION. THE ECMWF PET AND UNCALIBRATED
ENSEMBLE INDICATE AT LEAST A 20 PERCENT CHANCE 3-DAY PRECIPITATION TOTALS
EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE AND 1-INCH OVER BROAD PARTS OF THE
CENTRAL AND EAST-CENTRAL CONUS. A SLIGHT RISK FOR HEAVY PRECIPITATION IS POSTED
ACROSS PORTIONS OF THE GREAT PLAINS, MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS,
GREAT LAKES, AND SOUTHEAST FOR MAY 23-25. IF THE MORE ROBUST SCENARIO FROM THE
ECMWF IS CORRECT, THERE COULD BE INCREASING CHANCES OF HEAVY PRECIPITATION
SPREADING INTO PARTS OF THE NORTHEAST AROUND THE START OF THE MEMORIAL DAY
WEEKEND, BUT HOLDING OFF ON EXPANDING THE HAZARD DUE TO LESS AGREEMENT FROM THE
GEFS.
NO HAZARDS ARE ISSUED FOR ALASKA, WITH NEAR- TO BELOW-NORMAL TEMPERATURE
PROBABILITIES FAVORED FOR MOST OF THE STATE SOUTH OF THE BROOKS RANGE. SNOWMELT
SEASON IS UNDERWAY AND FROZEN RIVERS ARE BEGINNING TO BREAK UP, LEADING TO THE
POTENTIAL FOR RIVER FLOODING RELATED TO ICE-JAMS. HOWEVER, THERE ARE NO
INDICATIONS OF IMPENDING MAJOR RIVER BREAK-UPS OR SERIOUS THREAT OF ICE-JAMMING
SO NO FLOODING-RELATED HAZARDS ARE POSTED AT THIS TIME. CAUTION WILL CONTINUE
TO BE EXERCISED AS RIVER BREAK-UP CAN BE UNPREDICTABLE AND LOCAL CONDITIONS CAN
CHANGE QUICKLY. ANOMALOUS RIDGING OVER THE NORTH-CENTRAL PACIFIC FAVORS AN
ENHANCED STORM TRACK INTO WESTERN MAINLAND ALASKA, ALTHOUGH PRECIPITATION
AMOUNTS ARE EXPECTED TO REMAIN LOW AND NOT REACH HAZARDS THRESHOLDS.
FORECASTER: THOMAS COLLOW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page