284
FXUS21 KWNC 161842
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MAY 16 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 AND THE FLORIDA PENINSULA. MID-LEVEL LOW PRESSURE
PREDICTED ACROSS THE NORTHWESTERN AND NORTH-CENTRAL CONUS EARLY IN THE PERIOD
COULD LEAD TO A DISTURBANCE TRAVERSING THE CONUS SUPPORTING INCREASED
LIKELIHOOD 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, FRI-SAT, MAY 24-25.
SLIGHT RISK FOR EXCESSIVE HEAT ACROSS PORTIONS OF THE SOUTHERN PLAINS AND THE
FLORIDA PENINSULA, FRI-TUE, MAY 24-28.
SLIGHT RISK FOR HEAVY PRECIPITATION ACROSS PORTIONS OF THE GREAT PLAINS,
MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS, GREAT LAKES, SOUTHEAST AND
MID-ATLANTIC, FRI-SUN, MAY 24-26.
SLIGHT RISK FOR HIGH WINDS ACROSS PARTS OF THE FOUR CORNERS AND CENTRAL AND
SOUTHERN HIGH PLAINS, FRI-SUN, MAY 24-26.
RAPID ONSET DROUGHT RISK ACROSS THE SOUTHERN FLORIDA PENINSULA AND SOUTHERN
TEXAS.
DETAILED SUMMARY
FOR SUNDAY MAY 19 - THURSDAY MAY 23:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY MAY 24 - THURSDAY MAY 30: 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 WHERE THE GEFS AND ECENS
PROBABILISTIC EXTREMES TOOLS (PETS) DEPICT AT LEAST A 20 PERCENT CHANCE OF
MAXIMUM TEMPERATURES EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE AND 95 DEG F.
THE GEFS PET CONTINUES TO SHOW PROBABILITIES ABOVE 40 PERCENT ACROSS PORTIONS
OF SOUTHERN AND SOUTHWESTERN TEXAS, ALTHOUGH THE ECENS PET GENERALLY DEPICTS
PROBABILITIES ABOVE 30% FOR TEMPERATURES TO EXCEED THE 85TH PERCENTILE. 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 OF HEAT INDICES EXCEEDING THE 95TH CLIMATOLOGICAL PERCENTILE
OR 110 DEG F ACROSS PARTS OF SOUTHERN TEXAS, THE MODERATE RISK FOR EXCESSIVE
HEAT IS MAINTAINED FOR MAY 24-25. A BROADER SLIGHT RISK (20 TO 40% CHANCE)
CONTINUES ACROSS MUCH OF THE SOUTHERN HALF OF TEXAS AND SOUTHEASTERN NEW MEXICO
FOR DAYS 8-12. THE SLIGHT RISK IS REDUCED RELATIVE TO YESTERDAY ACROSS THE
NORTHERN AND EASTERN PORTIONS OF THE SHAPE. SIGNIFICANTLY RAINFALL IS EXPECTED
DURING WEEK-1 IN THESE AREAS AND A SHORTWAVE TROUGH LOOKS LIKE IT MAY WORK INTO
THE LOWER-MISSISSIPPI VALLEY DURING THE MIDDLE FOR THE PERIOD. THIS REDUCES THE
CHANCES FOR EXCESSIVE HEAT ACROSS THESE AREAS. FOR THE WESTERN SIDE OF THE
SLIGHT RISK AREA, EXCESSIVE HEAT IS LIKELY TO BE TEMPERATURE DRIVEN, BUT HIGHER
DEW POINTS FAVORED ACROSS SOUTHEASTERN TEXAS MAY PUSH HEAT INDICES ABOVE 105
DEG F DESPITE THE RELATIVELY LOWER TEMPERATURES COMPARED TO THOSE FURTHER WEST.
ACROSS PORTIONS OF SOUTHERN TEXAS, ABOVE-NORMAL TEMPERATURES CONTINUE TO BE
STRONGLY FAVORED THROUGH AT LEAST WEEK-2. PRECIPITATION IS ALSO FORECAST TO BE
BELOW-NORMAL DURING WEEK-1 AND 2 ACROSS PORTIONS OF THE REGION. THERE HAVE BEEN
NOTABLE DECLINES IN SOIL MOISTURE ACROSS SOUTHERN TEXAS IN RECENT WEEKS AND
ABNORMALLY DRY CONDITIONS HAVE EXPANDED OVER THE PAST FEW WEEKS. WITH CONTINUED
EXPECTATIONS FOR WARM AND DRY CONDITIONS, A RAPID ONSET DROUGHT (ROD) RISK HAS
BEEN INTRODUCED TO THE SOUTHERN TEXAS REGION TODAY.
THE ECENS 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 SIGNALS, THE SLIGHT RISK FOR EXCESSIVE HEAT
REMAINS FORECAST FOR MOST OF THE FLORIDA PENINSULA FOR DAYS 8-12, MAY 24-28. A
MODERATE RISK IS HIGHLIGHTED ACROSS THE SOUTHERN FLORIDA PENINSULA FROM MAY
24-25 WHERE THERE IS THE STRONGEST SIGNAL AMONG THE GEFS AND ECENS PET.
DECREASING SOIL MOISTURE AND A WARM AND DRY PATTERN PREDICTED IN WEEK-2 LEAD TO
INCREASED RISK FOR RAPID ONSET DROUGHT 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 ECENS AND GEFS DEPICT A SHORTWAVE DISTURBANCE MOVING ACROSS THE
CONUS EARLY IN WEEK-2. GIVEN THE POTENTIAL FOR A STORM 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 24-26. DETERMINISTIC RUNS
FROM THE 0Z GFS AND ECMWF DEPICTING WIND SPEEDS EXCEEDING 25-MPH OVER THESE
AREAS COMBINED WITH THE ANOMALOUSLY DRY CONDITIONS COULD ENHANCE THE WILDFIRE
RISK OVER THE REGION.
FURTHER EAST, THE ECENS PET AND UNCALIBRATED ENSEMBLE INDICATE AT LEAST A 20
PERCENT CHANCE OF 3-DAY PRECIPITATION TOTALS EXCEEDING THE 85TH CLIMATOLOGICAL
PERCENTILE AND 1-INCH ACROSS A BROAD AREA OF THE CENTRAL AND EAST-CENTRAL
CONUS. THE GEFS PET IS SOMEWHAT SUPPORTIVE OF THIS RISK ACROSS PORTIONS OF THE
MISSISSIPPI AND OHIO VALLEYS. THE ECENS PET BRINGS MUCH STRONGER CHANCES (>40%
CHANCE) OF PRECIPITATION EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE INTO
PORTIONS OF THE SOUTHEAST BUT THIS IS NOT SUPPORTED BY THE CORRESPONDING RAW
TOOLS OR THE GEFS PET. HOWEVER, THERE IS A SLIGHT EXPANSION SOUTH AND EAST OF
THE FORECAST PRECIPITATION HAZARD FROM YESTERDAY. THEREFORE, A SLIGHT RISK FOR
HEAVY PRECIPITATION IS POSTED ACROSS PORTIONS OF THE GREAT PLAINS, MISSISSIPPI,
TENNESSEE, AND OHIO VALLEYS, GREAT LAKES, SOUTHEAST, AND MID-ATLANTIC FOR MAY
24-26. IF THE MORE ROBUST SCENARIO FROM THE ECENS 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 SHOULD 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 HAZARDOUS THRESHOLDS.
FORECASTER: RYAN BOLT
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