942
FXUS21 KWNC 021851
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 02 2024
SYNOPSIS: MID-LEVEL HIGH PRESSURE IS FORECAST TO AMPLIFY ACROSS THE WESTERN
CONTIGUOUS U.S. (CONUS) FAVORING INCREASING CHANCES OF EXCESSIVE HEAT
CONDITIONS, PARTICULARLY OVER CALIFORNIA’S CENTRAL VALLEY AND THE DESERT
SOUTHWEST WHERE THE HOTTEST TEMPERATURES ARE FORECAST. HURRICANE BERYL,
CURRENTLY NEAR THE DOMINICAN REPUBLIC, MAY BRING IMPACTS TO PORTIONS OF THE
COASTAL PORTIONS OF TEXAS AND LOUISIANA EARLY IN WEEK-2, ALTHOUGH UNCERTAINTY
REMAINS HIGH. SOUTHERLY MOIST FLOW INTO THE SOUTHWEST CONTINUES INCREASED
CHANCES FOR LOCALIZED HEAVY PRECIPITATION IN THE REGION. PERIODS OF POTENTIALLY
HIGH WINDS ACROSS THE CASCADES, SOUTHWESTERN OREGON, AND CENTRAL AND NORTHERN
CALIFORNIA MAY INCREASE THE RISK FOR WILDFIRES IN THE AREA.
HAZARDS
HIGH RISK OF EXCESSIVE HEAT FOR THE GREAT BASIN, CALIFORNIA, SOUTHWEST, AND
NORTHERN ROCKIES, WED-THU, JUL 10-11.
MODERATE RISK OF EXCESSIVE HEAT FOR THE WESTERN THIRD OF THE CONUS AND NORTHERN
PLAINS, WED-FRI, JUL 10-12.
SLIGHT RISK OF EXCESSIVE HEAT FOR THE WESTERN THIRD OF THE CONUS AND NORTHERN
AND CENTRAL PLAINS, WED-TUE, JUL 10-16.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF ARIZONA AND WESTERN NEW
MEXICO, SAT-TUE, JUL 13-16.
SLIGHT RISK FOR PERIODS OF HEAVY PRECIPITATION FOR PORTIONS OF SOUTHEASTERN
TEXAS AND THE LOWER MISSISSIPPI VALLEY, WED-FRI, JUL 10-12.
SLIGHT RISK FOR HIGH WINDS ALONG THE LOUISIANA AND EASTERN TEXAS COAST,
WED-THU, JUL 10-11.
SLIGHT RISK OF EPISODIC HIGH WINDS ACROSS THE CASCADES, SOUTHWESTERN OREGON,
AND CENTRAL AND NORTHERN CALIFORNIA, WED-SUN, JUL 10-14.
RAPID ONSET DROUGHT RISK FOR PARTS OF GREAT PLAINS, MISSISSIPPI VALLEY,
TENNESSEE AND OHIO VALLEYS, APPALACHIANS, SOUTHEAST AND MID-ATLANTIC.
DETAILED SUMMARY
FOR FRIDAY JULY 05 - TUESDAY JULY 09:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR WEDNESDAY JULY 10 - TUESDAY JULY 16: ANOMALOUS RIDGING IS FORECAST TO
EXPAND ACROSS THE WESTERN CONUS DURING WEEK-1 AND PERSIST INTO WEEK-2. THERE IS
AN INCREASED SIGNAL FOR TEMPERATURES COMPARED TO YESTERDAY, EXCEEDING THE 85TH
CLIMATOLOGICAL PERCENTILE ACROSS PORTIONS OF THE WESTERN THIRD OF THE CONUS IN
THE GEFS PROBABILISTIC EXTREMES TOOL (PET), COMING MORE IN LINE WITH THE HIGH
PROBABILITIES IN THE ECENS PET. THUS THE HIGH RISK OF EXCESSIVE HEAT IS
EXPANDED TODAY ACROSS THE GREAT BASIN, CALIFORNIA, SOUTHWEST, AND NORTHERN
ROCKIES, JUL 10-11, WHERE THESE TOOLS INDICATE AT LEAST A 60% CHANCE OF
EXCEEDING THE 85TH PERCENTILE. THE HOTTEST TEMPERATURES ARE ANTICIPATED FOR THE
CALIFORNIA CENTRAL VALLEY AND DESERT SOUTHWEST, WHERE UNCALIBRATED ENSEMBLE
MEANS SHOW TEMPERATURES REACHING 115 DEG F. 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 MODERATE RISK OF EXCESSIVE HEAT IS ALSO
EXPANDED COMPARED TO YESTERDAY, TO INCLUDE THE WESTERN THIRD OF THE CONUS AND
NORTHERN PLAINS, JUL 10-12, WHERE PETS INDICATE AT LEAST A 40-60% CHANCE OF
TEMPERATURES EXCEEDING THE 85TH PERCENTILE AND/OR WHERE UNCALIBRATED GUIDANCE
SHOWS ELEVATED HEAT RISK. PETS INDICATE MAXIMUM TEMPERATURES EXCEEDING THE MID
90S DEG F ACROSS THE NORTHERN AND CENTRAL PLAINS. A BROADER AREA OF SLIGHT RISK
(20-40% CHANCE) CONTINUES THROUGHOUT WEEK-2 ACROSS THE WESTERN THIRD OF THE
CONUS AND THE NORTHERN AND CENTRAL PLAINS.
POSSIBLE SURFACE LOW FORMATION WITH ADJACENT SURFACE HIGH PRESSURE OVER THE
NORTHERN PACIFIC MAY SUPPORT TIGHT PRESSURE GRADIENTS ACROSS THE NORTHWEST AND
CALIFORNIA, THUS A SLIGHT RISK OF EPISODIC HIGH WINDS IS HIGHLIGHTED FOR THE
CASCADES AND NORTHERN AND CENTRAL CALIFORNIA, JUL 10-14. THE GEFS (ECENS) PET
SHOWS AT LEAST A 20% (30%) CHANCE OF WIND SPEEDS OVER SOUTHWESTERN OREGON AND
NORTHERN AND CENTRAL CALIFORNIA EXCEEDING THE 85TH PERCENTILE. HOT, DRY, AND
WINDY CONDITIONS MAY LEAD TO ENHANCED RISK OF WILDFIRES ACROSS WEST COAST
STATES, ESPECIALLY LOCATIONS ALREADY UNDER RED FLAG WARNINGS.
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. THEREFORE, A SLIGHT RISK OF PERIODIC HEAVY PRECIPITATION IS POSTED
ACROSS PORTIONS OF ARIZONA AND WESTERN NEW MEXICO, JUL 13-16. LOCALIZED
FLOODING IS POSSIBLE ACROSS THIS AREA, ALTHOUGH THERE IS TOO MUCH UNCERTAINTY
AT THIS TIME TO DESIGNATE A FLOOD RISK.
AS OF 2PM EDT TUESDAY, HURRICANE BERYL IS A CATEGORY-5 HURRICANE NEAR THE
DOMINICAN REPUBLIC. PER THE NATIONAL HURRICANE CENTER (NHC), THIS SYSTEM IS
FORECAST TO TRACK ACROSS THE CARIBBEAN GRADUALLY WEAKENING 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 CONTINUES TO BE
A RANGE OF ENSEMBLE SOLUTIONS, WITH SOME FAVORING A MORE NORTHWARD TRACK OF THE
SYSTEM (OR ITS REMNANTS) MORE NORTHWARD, BRINGING IT CLOSER TO THE WESTERN GULF
COAST AROUND THE START OF WEEK-2 AND OTHERS INDICATING A MORE SOUTHERLY TRACK
INTO MEXICO. REGARDLESS THERE IS AT LEAST SOME CONCERN FOR U.S. IMPACTS GIVEN
ANTICIPATED MOIST FLOW. A SLIGHT RISK OF PERIODS OF HEAVY PRECIPITATION (20-40%
CHANCE) IS CONTINUED FOR PORTIONS OF SOUTHEASTERN TEXAS AND THE LOWER
MISSISSIPPI VALLEY, JUL 10-16. THE MODERATE RISK (40-60% CHANCE) OF HEAVY
PRECIPITATION IS NOT INCLUDED TODAY DUE TO INCREASED UNCERTAINTY OF THIS
DISTURBANCE. THE SLIGHT RISK OF HIGH WINDS HAS BEEN EXPANDED EASTWARD TO
INCLUDE COASTAL TEXAS AND LOUISIANA, JUL 10-11 BASED ON THE RANGE OF POSSIBLE
ENSEMBLE SURFACE LOWS. POSSIBLE HEAVY PRECIPITATION COULD LEAD TO FLOODING,
ALTHOUGH THERE IS TOO MUCH UNCERTAINTY AT THIS TIME TO SPECIFY A RELATED RISK
AREA.
MID-LEVEL TROUGHING PREDICTED OVER THE GREAT LAKES AND OHIO VALLEY MAY SUPPORT
A LINGERING STATIONARY FRONT OVER THE EASTERN SEABOARD FROM THE END OF WEEK-1
INTO WEEK-2. THE ECENS PET INDICATES PORTIONS OF THE EAST COAST HAVING AT LEAST
A 20% CHANCE OF 3-DAY RAINFALL EXCEEDING THE 85TH PERCENTILE AND ONE INCH,
ALTHOUGH THE GEFS KEEPS THE ENHANCED RAINFALL MORE OFFSHORE. DUE TO HIGH
UNCERTAINTY, A RELATED HEAVY PRECIPITATION HAZARD IS NOT DESIGNATED FOR THIS
REGION.
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. PERIODIC, LOCALIZED
HEAVY PRECIPITATION CANNOT BE RULED OUT DUE TO FRONTAL AND/OR DAYTIME
THUNDERSTORM ACTIVITY, BUT THIS IS UNLIKELY TO RESULT IN ANY MEANINGFUL CHANGE
IN THE POTENTIAL FOR CONTINUED DEVELOPMENT OF DROUGHT CONDITIONS. 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: MELISSA OU
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