167
FXUS21 KWNC 021905
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MAY 02 2024
SYNOPSIS: MID-LEVEL HIGH PRESSURE IS FORECAST TO LINGER FROM THE END OF WEEK-1
INTO THE BEGINNING OF WEEK-2 OVER THE SOUTH-CENTRAL AND SOUTHEASTERN CONUS,
WEAKENING SIGNIFICANTLY BY THE MIDDLE OF THE PERIOD. THIS MAY INCREASE CHANCES
FOR EXCESSIVE HEAT HANGING AROUND THE GULF COAST STATES AND SOUTH CAROLINA,
ALBEIT A MORE SCOPED AREA ACROSS THE SOUTH COMPARED TO YESTERDAY. PASSAGE OF A
FRONT MAY BRING HEAVY RAIN TO PARTS OF THE LOWER MISSISSIPPI AND TENNESSEE
VALLEYS, AND SOUTHERN APPALACHIANS AT THE START OF THE PERIOD. SURFACE LOWS
PREDICTED OVER THE FOUR CORNERS MAY SUPPORT PERIODS OF HIGH WINDS ACROSS PARTS
OF THE FOUR CORNERS AND SOUTHERN PLAINS. DRY SOILS COMBINED WITH LITTLE
ANTICIPATED PRECIPITATION DURING WEEKS 1 AND 2 SUPPORTS THE POTENTIAL FOR RAPID
ONSET DROUGHT ACROSS PARTS OF THE FLORIDA PENINSULA.
HAZARDS
MODERATE RISK OF EXCESSIVE HEAT FOR PARTS OF THE GULF COAST STATES AND SOUTH
CAROLINA, FRI, MAY 10.
SLIGHT RISK OF EXCESSIVE HEAT FOR PARTS OF THE GULF COAST STATES AND SOUTH
CAROLINA, FRI-SAT, MAY 10-11.
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS PARTS OF THE LOWER MISSISSIPPI AND
TENNESSEE VALLEYS, AND SOUTHERN APPALACHIANS, FRI-SAT, MAY 10-11.
SLIGHT RISK OF EPISODES OF HIGH WINDS FOR PARTS OF THE FOUR CORNERS AND
SOUTHERN PLAINS, FRI-SUN, MAY 10-12.
RAPID ONSET DROUGHT RISK OVER PARTS OF THE FLORIDA PENINSULA.
DETAILED SUMMARY
FOR SUNDAY MAY 05 - THURSDAY MAY 09:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY MAY 10 - THURSDAY MAY 16: THE 0Z GEFS, ECENS, AND CANADIAN ENSEMBLE
MEANS ARE IN GOOD AGREEMENT TODAY INDICATING MID-LEVEL RIDGING LINGERING FROM
THE END OF WEEK-1 INTO THE BEGINNING OF WEEK-2 ACROSS THE SOUTH-CENTRAL AND
SOUTHEASTERN CONUS BEFORE WEAKENING.THE SLIGHT RISK OF EXCESSIVE HEAT HAS BEEN
DECREASED IN COVERAGE AND TIME ACROSS PARTS OF THE GULF COAST STATES AND SOUTH
CAROLINA, MAY 10 TO 11, WHERE THE GEFS AND ECENS PROBABILISTIC EXTREMES TOOLS
(PETS) SHOW AT LEAST A 20% CHANCE OF MAXIMUM TEMPERATURES EXCEEDING THE 85TH
PERCENTILE, CLIMATOLOGICALLY, AND 90 DEG F (100 DEG F ACROSS SOUTHWESTERN
TEXAS). AN EMBEDDED AREA IS DESIGNATED WITH A MODERATE RISK (40 TO 60% CHANCE)
FOR DAY 8 ONLY (MAY10) WHERE THE ECENS (GEFS) PET SHOWS AT LEAST A 50% (40%)
CHANCE OF MAXIMUM TEMPERATURES EXCEEDING THE 85TH PERCENTILE ACROSS MUCH OF THE
MODERATE RISK AREA. THE NATIONAL BLEND OF MODELS (NBM) SHOWS RELATIVELY
WIDESPREAD POTENTIAL FOR RECORD HIGH TEMPERATURES, MAY 9TH, IN THE LOW TO MID
90S ACROSS THE LOWER MISSISSIPPI VALLEY AND FLORIDA, WITH TRIPLE DIGITS (DEG F)
ACROSS SOUTHWESTERN TEXAS.
MULTIPLE MODELS SHOW THE POTENTIAL OF A FRONT EXTENDING FROM THE NORTHEAST TO
SOUTHERN PLAINS AT THE BEGINNING OF THE PERIOD, WHICH COULD BRING ENHANCED
RAINFALL TO PARTS OF THE SOUTHEASTERN CONUS. THERE IS SIGNIFICANT UNCERTAINTY
REGARDING THE SPECIFIC AREAS THAT WOULD GET THE HEAVIEST PRECIPITATION, WITH
THIS FRONT EXPECTED TO BE FAIRLY PROGRESSIVE AND HEAVY PRECIPITATION TO BE
RELATIVELY LOCALIZED. A GENERAL AREA OF SLIGHT RISK IS DESIGNATED ACROSS PARTS
OF THE LOWER MISSISSIPPI AND TENNESSEE VALLEYS, AND SOUTHERN APPALACHIANS, MAY
10-11, PRIMARILY BASED ON WHERE THE ECENS (GEFS) PET SHOWS AT LEAST A 20% (30%)
CHANCE OF 3-DAY (DAY 8-10) RAINFALL TOTALS EXCEEDING THE 85TH PERCENTILE AND
ONE INCH (0.75 INCHES), AND UNCALIBRATED TOTALS. DUE TO DECREASING WET SIGNALS
DURING WEEK-1 AND WEEK-2, THE NWC DOES NOT HAVE A POSSIBLE FLOOD RISK DURING
THE 4 TO 7 DAY PERIOD, THUS THE FLOOD RISK IS DISCONTINUED IN TODAY’S OUTLOOK.
A SERIES OF SURFACE LOWS ARE ANTICIPATED TO FORM OVER THE SOUTHWESTERN CONUS AT
THE BEGINNING OF WEEK-2. THESE DISTURBANCES COMBINED WITH ADJACENT SURFACE HIGH
PRESSURE OVER THE NORTH PACIFIC SUPPORTS AREAS OF TIGHT PRESSURE GRADIENTS AND
RESULTANT INCREASED CHANCES FOR HIGH WINDS ACROSS THE SOUTHWESTERN CONUS. A
SLIGHT RISK OF EPISODIC HIGH WINDS IS CONTINUED ACROSS PARTS OF THE FOUR
CORNERS AND SOUTHERN PLAINS, MAY 10-12 BASED ON WHERE BOTH THE GEFS AND ECENS
PETS SHOWS AT LEAST A 20% CHANCE OF WIND SPEEDS EXCEEDING THE 85TH PERCENTILE
AND 20 MPH ACROSS THE HIGHLIGHTED RISK AREA IN ADDITION TO WHERE RECENT
DETERMINISTIC MODEL RUNS INDICATE ENHANCED WIND SPEEDS AND SURFACE LOW
FORMATION. ANTICIPATED INCREASED POTENTIAL FOR HIGH WINDS COMBINED WITH DRY
SOILS AND ANTECEDENT AND EXPECTED DRY CONDITIONS SUPPORTS ENHANCED RISK FOR
WILDFIRES, ESPECIALLY ACROSS THE BIG BEND OF TEXAS, NEW MEXICO, AND ARIZONA,
WHERE THE NATIONAL INTERAGENCY FIRE CENTER (NIFC) SHOWS MODERATE RISK OF
SIGNIFICANT FIRE POTENTIAL BY THE END OF WEEK-1.
ABOVE-NORMAL TEMPERATURES AND NEAR- TO BELOW-NORMAL PRECIPITATION IS FORECAST
DURING WEEKS 1 AND 2 ACROSS THE CENTRAL FLORIDA PENINSULA. ADDITIONALLY, SOIL
MOISTURE LEVELS ARE DECLINING DUE TO LIMITED PRECIPITATION IN RECENT WEEKS AND
MONTHS. RECENT WEEKS HAVE SEEN AREAS OF ABNORMAL DRYNESS (D0) DEVELOPING AND
EXPANDING. INCREASING SUN ANGLE AND TEMPERATURES IN THE 80-90 DEG F COULD LEAD
TO FURTHER DRYING OF SOILS AND POTENTIALLY LEAD TO DROUGHT CONDITIONS ACROSS
THIS REGION. THEREFORE, AN AREA OF RAPID ONSET DROUGHT (ROD) IS POSTED FOR
PORTIONS OF CENTRAL FLORIDA, WHERE SEVERE DROUGHT IS NOT ALREADY OCCURRING.
IN ALASKA, SNOWMELT SEASON IS UNDERWAY AND FROZEN RIVERS ARE BEGINNING TO BREAK
UP. CURRENTLY THERE ARE LIMITED AREAS IN FLOOD WATCH, ALTHOUGH THERE COULD BE
INCREASED POTENTIAL FOR RIVER FLOODING RELATED TO ICE-JAMS OVER THE NEXT COUPLE
WEEKS. WE CONTINUE TO MONITOR THE SITUATION BUT CURRENTLY THERE ARE NO
INDICATIONS OF IMPENDING MAJOR RIVER FLOODING RELATED TO ICE BREAK-UPS SO NO
FLOODING-RELATED HAZARDS ARE POSTED AT THIS TIME.
FORECASTER: MELISSA OU
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