107
FXUS21 KWNC 011906
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 01 2024
SYNOPSIS: MID-LEVEL HIGH PRESSURE IS FORECAST TO AMPLIFY ACROSS THE WESTERN
CONTIGUOUS U.S. FAVORING INCREASING CHANCES OF EXCESSIVE HEAT CONDITIONS,
PARTICULARLY OVER THE CALIFORNIA CENTRAL VALLEY AND THE DESERT SOUTHWEST WHERE
THE HOTTEST TEMPERATURES ARE FORECAST. A FRONTAL SYSTEM IS FORECAST TO MOVE
THROUGH THE EASTERN U.S. EARLY IN WEEK-2 LEADING TO A REPRIEVE FROM THE HEAT,
ALTHOUGH EXCESSIVE HEAT MAY LINGER ALONG THE EASTERN SEABOARD AT THE OUTSET OF
THE PERIOD. HURRICANE BERYL, CURRENTLY NEAR THE WINDWARD ISLANDS, MAY BRING
IMPACTS TO PORTIONS OF THE WESTERN GULF COAST EARLY IN WEEK-2, ALTHOUGH
UNCERTAINTY REMAINS HIGH.
HAZARDS
HIGH RISK FOR EXCESSIVE HEAT FOR PORTIONS OF THE CALIFORNIA CENTRAL VALLEY AND
THE DESERT SOUTHWEST, TUE-THU, JUL 9-11.
MODERATE RISK FOR EXCESSIVE HEAT FOR PORTIONS OF CALIFORNIA, PACIFIC NORTHWEST,
GREAT BASIN, AND DESERT SOUTHWEST, TUE-FRI, JUL 9-12.
SLIGHT RISK FOR EXCESSIVE HEAT FOR MUCH OF THE WESTERN CONUS AND THE NORTHERN
AND CENTRAL PLAINS, TUE-MON, JUL 9-15.
SLIGHT RISK FOR EXCESSIVE HEAT FOR PORTIONS OF THE MID-ATLANTIC AND NORTHEAST,
TUE, JUL 9.
MODERATE RISK FOR HEAVY PRECIPITATION ALONG THE EASTERN TEXAS COAST, TUE-WED,
JUL 9-10.
SLIGHT RISK FOR HEAVY PRECIPITATION FOR PORTIONS OF SOUTHEASTERN TEXAS AND THE
LOWER MISSISSIPPI VALLEY, TUE-THU, JUL 9-11.
SLIGHT RISK FOR HEAVY PRECIPITATION FOR PORTIONS OF ARIZONA AND WESTERN NEW
MEXICO, FRI-MON, JUL 12-15.
SLIGHT RISK FOR HIGH WINDS ALONG THE EASTERN TEXAS COAST, TUE-WED, JUL 9-10.
RAPID ONSET DROUGHT RISK FOR PARTS OF GREAT PLAINS, MISSISSIPPI VALLEY,
TENNESSEE AND OHIO VALLEYS, APPALACHIANS, SOUTHEAST AND MID-ATLANTIC.
DETAILED SUMMARY
FOR THURSDAY JULY 04 - MONDAY JULY 08:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY JULY 09 - MONDAY JULY 15: ANOMALOUS RIDGING IS FORECAST TO EXPAND
ACROSS THE WESTERN CONUS DURING WEEK-1 AND PERSIST INTO WEEK-2. THIS FAVORS
WIDESPREAD ABOVE-NORMAL TEMPERATURES, WITH MANY AREAS HAVING AN INCREASED RISK
FOR EXCESSIVE HEAT. THE UNCALIBRATED 0Z ECENS AND GEFS DEPICT THE HOTTEST
TEMPERATURES ACROSS THE CALIFORNIA CENTRAL VALLEY AND DESERT SOUTHWEST WITH
SOME LOCATIONS EXCEEDING 115 DEG F. THE ECENS PROBABILISTIC EXTREMES TOOLS
(PET) DEPICTS GREATER THAN A 60 PERCENT CHANCE MAXIMUM TEMPERATURES EXCEED THE
85TH CLIMATOLOGICAL PERCENTILE OVER THESE AREAS, AS WELL AS OVER PARTS OF THE
GREAT BASIN. THE GEFS PET IS SLIGHTLY LESS ROBUST COMPARED TO THE ECENS BUT
STILL DEPICTS AN EXPANSIVE AREA OF THE WEST WITH GREATER THAN A 40 PERCENT
CHANCE MAXIMUM TEMPERATURES EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE. A HIGH
RISK OF EXCESSIVE HEAT IS HIGHLIGHTED OVER THE CALIFORNIA CENTRAL VALLEY AND
DESERT SOUTHWEST JUL 9-11, CORRESPONDING WITH WHERE THE HOTTEST TEMPERATURES
ARE FORECAST. THE MODERATE RISK CONTINUES THROUGH JUL 12 AND INCLUDES MUCH OF
THE NON-COASTAL AREAS OF THE PACIFIC NORTHWEST AND GREAT BASIN GIVEN THE HIGHER
PROBABILITIES IN THE PETS, AND WHERE TEMPERATURES IN SOME OF THE VALLEYS MAY
EXCEED 100 DEG F (90 DEG F CLOSER TO THE COAST). THE SLIGHT RISK IS VALID FOR
ALL OF WEEK-2 FOR MUCH OF THE WEST, AND ALSO EXTENDS INTO PARTS OF THE NORTHERN
AND CENTRAL PLAINS GIVEN THE EASTWARD MIGRATION OF THE RIDGE AXIS LATER IN THE
PERIOD.
THE INITIAL POSITION OF THE RIDGE AXIS NEAR THE DESERT SOUTHWEST, FAVORS A
DIMINISHING MONSOON SIGNAL EARLY IN WEEK-2. HOWEVER, THE RIDGE IS FORECAST TO
SHIFT MORE TO THE EAST LATER IN THE PERIOD TOWARD THE FOUR CORNERS, WHICH IS
MORE FAVORABLE FOR SOUTHERLY MOISTURE FLOW INTO PARTS OF THE SOUTHWEST. THE
PETS INDICATE A GROWING SIGNAL FOR HEAVY PRECIPITATION LATER IN WEEK-2, WITH
PROBABILITIES ABOVE 20 PERCENT FOR 3-DAY PRECIPITATION TOTALS EXCEEDING THE
85TH CLIMATOLOGICAL PERCENTILE AND 0.5 INCHES DURING THE MIDDLE AND END OF THE
PERIOD (40 PERCENT IN THE ECENS PET). THEREFORE, A SLIGHT RISK OF HEAVY
PRECIPITATION IS POSTED ACROSS PORTIONS OF ARIZONA AND WESTERN NEW MEXICO, JUL
12-15. DUE TO THE DECREASED PRECIPITATION SIGNALS EARLY IN THE PERIOD, THE
FLOODING POSSIBLE AREA HAS BEEN DISCONTINUED OVER THE REGION.
TROUGHING IS FORECAST ACROSS THE NORTH-CENTRAL CONUS LATE IN WEEK-1, WHICH
FAVORS THE PROGRESSION OF A FRONTAL SYSTEM THROUGH THE EASTERN CONUS DURING
THIS TIMEFRAME AND A DIMINISHING OF THE EXCESSIVE HEAT RISK FOR MUCH OF THE
EAST. PETS AND UNCALIBRATED GUIDANCE CONTINUE TO SUPPORT A LINGERING SLIGHT
RISK OF EXCESSIVE HEAT ON DAY-8 (JUL 9) ACROSS PORTIONS OF THE EASTERN
SEABOARD. TEMPERATURES IN THE LOW TO MID-90S COMBINED WITH SOUTHERLY FLOW AHEAD
OF THE INCOMING FRONT AND HIGHER HUMIDITY LEVELS COULD PUSH HEAT INDICES ABOVE
100 (105) DEG F ACROSS PARTS OF THE NORTHEAST (MID-ATLANTIC). TEMPERATURES ARE
FORECAST TO DROP BELOW EXCESSIVE HEAT CRITERIA FOLLOWING THE FRONTAL PASSAGE,
BUT AN OVERALL BROADENING OF THE RIDGE ACROSS THE CONUS AND INCREASING
MID-LEVEL HEIGHTS LATER IN WEEK-2 MAY LEAD TO INCREASED EXCESSIVE HEAT CHANCES
TO RETURN BY THE END OF THE PERIOD. DRYING OUT IS ALSO FAVORED ACROSS PARTS OF
THE UPPER MIDWEST BEHIND THE FRONT, WHICH SHOULD REDUCE THE FLOODING POTENTIAL.
THEREFORE, THE FLOODING POSSIBLE HAZARD HAS BEEN DISCONTINUED ACROSS THIS
REGION.
AS OF 2PM EDT MONDAY, HURRICANE BERYL IS A CATEGORY-4 HURRICANE NEAR THE
WINDWARD ISLANDS. PER THE NATIONAL HURRICANE CENTER (NHC), THIS SYSTEM IS
FORECAST TO TRACK ACROSS THE CARIBBEAN BUT ENCOUNTER A LESS FAVORABLE
ENVIRONMENT AS IT APPROACHES THE YUCATAN LATER THIS WEEK. THE BIG QUESTION IS
WHAT WILL HAPPEN IF THE CIRCULATION CROSSES THE YUCATAN INTO THE GULF OF
MEXICO. THERE ARE A SIGNIFICANT NUMBER OF ECENS ENSEMBLE MEMBERS (AND SOME GEFS
MEMBERS) THAT TURN THE SYSTEM (OR ITS REMNANTS) MORE NORTHWARD, BRINGING IT
CLOSER TO THE WESTERN GULF COAST AROUND THE START OF WEEK-2. WHILE A MORE
SOUTHERLY TRACK INTO MEXICO REMAINS POSSIBLE, THERE IS AT LEAST SOME CONCERN
FOR U.S. IMPACTS. EVEN IF BERYL STAYS TO THE SOUTH, SOME GEFS MEMBERS ALSO
INDICATE THE DISTURBANCE BEHIND BERYL (INVEST 96L, CURRENTLY GIVEN A 50 PERCENT
CHANCE OF DEVELOPMENT INTO A TROPICAL CYCLONE IN THE NEXT WEEK BY NHC) MAY ALSO
EVENTUALLY TRACK TOWARD THE GULF OF MEXICO. THE GEFS PET INDICATES
PROBABILITIES GREATER THAN 30 PERCENT FOR 3-DAY PRECIPITATION TO EXCEED THE
85TH CLIMATOLOGICAL PERCENTILE ACROSS SOUTH TEXAS. THE ECENS PET DEPICTS
PROBABILITIES ABOVE 40 PERCENT FOR MUCH OF EASTERN TEXAS, WITH 20 PERCENT OR
GREATER PROBABILITIES EXTENDING FURTHER NORTH AND EAST INTO OKLAHOMA AND THE
LOWER MISSISSIPPI VALLEY. THEREFORE, A MODERATE RISK OF HEAVY PRECIPITATION IS
HIGHLIGHTED ALONG THE EASTERN TEXAS COAST, JUL 9-10, WITH A SLIGHT RISK
EXTENDING THROUGH MORE OF THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY
THROUGH JUL 11. A SLIGHT RISK OF HIGH WINDS IS ALSO POSTED ACOSS COASTAL TEXAS
FOR JUL 9-10.
THE PERSISTENT WARMER AND DRIER THAN NORMAL CONDITIONS OVER AT LEAST THE PAST
MONTH HAVE LED TO A RISK FOR RAPID ONSET DROUGHT FOR PARTS OF THE OHIO VALLEY
(EASTERN CORN BELT), MID-ATLANTIC, SOUTHEAST, SOUTHERN PLAINS, AND SOUTHERN
CENTRAL PLAINS. THE RECENT HEAT WAVES ACROSS THE EASTERN U.S. HAVE EXACERBATED
THE ONGOING DRYNESS ACROSS THESE AREAS, AND HAVE LED TO MODERATE DROUGHT (D1)
FOR MANY AREAS IN THE EAST. MUCH OF THE AREAS HIGHLIGHTED FOR RISK OF RAPID
ONSET DROUGHT HAVE SEEN LARGE PRECIPITATION DEFICITS OVER THE PAST TWO WEEKS TO
A MONTH AND HAVE SEEN LARGE REDUCTIONS IN AVAILABLE SOIL MOISTURE. THERE IS
ADDITIONAL RISK FOR HIGH EVAPOTRANSPIRATION RATES WITH ABOVE-NORMAL
TEMPERATURES FORECAST ACROSS MUCH OF THE EASTERN CONUS. ALTHOUGH PERIODIC,
LOCALIZED HEAVY PRECIPITATION CANNOT BE RULED OUT DUE TO FRONTAL AND/OR DAYTIME
THUNDERSTORM ACTIVITY. DRY SOILS, STRESSED VEGETATION, AND REDUCED WATER
AVAILABILITY DUE TO LOW PONDS AND STREAMS MAY LEAD TO INCREASED IMPACTS TO
AGRICULTURE AND LIVESTOCK, WITH SEVERAL LOCATIONS ALREADY EXPERIENCING IMPACTS.
FORECASTER: THOMAS COLLOW
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