632
FXUS21 KWNC 251909
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 25 2024
SYNOPSIS: COAST-TO-COAST MID-LEVEL HIGH PRESSURE IS PREDICTED ACROSS THE
CONTIGUOUS U.S. (CONUS) DURING WEEK-2. THIS IS FAVORED TO BRING
WARMER-THAN-NORMAL TEMPERATURES FOR MOST OF THE LOWER 48 STATES. EXCESSIVE HEAT
IS MOST LIKELY ACROSS THE INTERIOR NORTHWEST, CENTRAL, AND NORTHEASTERN CONUS
DURING THE WEEK-2 OUTLOOK PERIOD. MODEL RUNS SUPPORT SOME STRENGTHENING OF THE
HEAT SIGNAL ACROSS THE NORTHERN PLAINS, NORTHERN ROCKIES, AND NORTHERN
INTERMOUNTAIN REGION. IN ALASKA, MID-LEVEL LOW PRESSURE IS FORECASTED ACROSS
MOST OF THE STATE, WITH THE EXCEPTION OF THE ALEUTIAN ARCHIPELAGO WHERE
MID-LEVEL HIGH PRESSURE IS FAVORED.
HAZARDS
HIGH RISK OF EXCESSIVE HEAT FOR THE SOUTH-CENTRAL PLAINS, FRI-SAT, AUG 2-3.
MODERATE RISK OF EXCESSIVE HEAT FOR THE NORTHEAST AND MID-ATLANTIC REGION,
FRI-TUE, AUG 2-6.
MODERATE RISK OF EXCESSIVE HEAT FOR MUCH OF THE INTERIOR WEST, AND ALL BUT FAR
SOUTHERN PORTIONS OF THE GREAT PLAINS, FRI-THU, AUG 2-8.
SLIGHT RISK OF EXCESSIVE HEAT FOR THE INTERIOR WEST (INCLUDING THE CENTRAL
VALLEY OF CALIFORNIA), MOST OF THE GREAT PLAINS, MOST OF THE MISSISSIPPI AND
OHIO VALLEYS, THE GREAT LAKES REGION, NORTHEAST, AND MID-ATLANTIC, FRI-THU, AUG
2-8.
RAPID ONSET DROUGHT RISK FOR MUCH OF THE GREAT PLAINS, AND INTO WESTERN
MISSOURI.
DETAILED SUMMARY
FOR SUNDAY JULY 28 - THURSDAY AUGUST 01:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY AUGUST 02 - THURSDAY AUGUST 08: FOR THE WEEK-2 PERIOD, ENSEMBLE
MEANS FAVOR ANOMALOUS MID-LEVEL RIDGING AND ACCOMPANYING POSITIVE HEIGHT
DEPARTURES ACROSS THE CONUS, WITH MAXIMUM 500-HPA HEIGHTS OF AT LEAST 594 DM
ACROSS THE SOUTHWESTERN AND SOUTH-CENTRAL STATES. BASED ON THE PREDICTED
PATTERN, THE WEEK-2 TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL TEMPERATURES OVER
ALMOST ALL OF THE CONUS. A SLIGHT RISK OF EXCESSIVE HEAT IS DEPICTED ACROSS
MOST OF THE LOWER 48 STATES, WITH THE EXCEPTION OF THE SOUTHEAST, SOUTHERN
TEXAS, AND NEAR THE PACIFIC COAST, VALID FOR THE ENTIRE OUTLOOK PERIOD. WITHIN
THIS EXTENSIVE SLIGHT RISK AREA, THERE ARE TWO AREAS WHERE A MODERATE RISK OF
EXCESSIVE HEAT IS FAVORED. ONE AREA INCLUDES THE NORTHEAST AND MUCH OF THE
MID-ATLANTIC REGION, VALID AUG 2-6. THE SECOND, LARGER AREA INCLUDES MUCH OF
THE INTERIOR WEST, AND MOST OF THE GREAT PLAINS, AUG 2-8. THIS REPRESENTS A
SIGNIFICANT EXPANSION OF YESTERDAY’S CORRESPONDING MODERATE RISK SHAPE, AND NOW
INCLUDES THE NORTHERN ROCKIES AND NORTHERN INTERMOUNTAIN REGION. WITHIN THIS
SECOND, LARGER AREA, THERE IS A HIGH RISK OF EXCESSIVE HEAT FOR THE
SOUTH-CENTRAL PLAINS WHICH HAS DECREASED SLIGHTLY IN COVERAGE COMPARED TO
YESTERDAY, AND IS VALID FOR ONLY THE FIRST TWO DAYS OF THE OUTLOOK PERIOD (AUG
2-3). A GENERAL CONSENSUS OF TEMPERATURE AND EXCESSIVE HEAT GUIDANCE INDICATES
ACTUAL AIR TEMPERATURES ACROSS PORTIONS OF THE NORTHEAST AND MID-ATLANTIC
REGION MAY REACH WELL INTO THE 90’S, WITH HEAT INDEX VALUES EXCEEDING 100 DEG
F. FOR THE PLAINS, MAXIMUM AIR TEMPERATURES OF 100-105 DEG F ARE EXPECTED, WITH
HEAT INDEX VALUES SURPASSING 110 DEG F OVER PORTIONS OF THE SOUTH-CENTRAL
PLAINS. A SKILL WEIGHTED, BIAS-CORRECTED HYBRID TOOL (WHICH CONSIDERS ACTUAL
AIR TEMPERATURE AND HEAT INDEX), RAW TEMPERATURES FROM THE GEFS AND ECENS
ENSEMBLE MEANS, AND PROBABILISTIC EXTREMES TOOL (PET) TEMPERATURES WERE USED IN
THE CONSTRUCTION OF TODAY’S EXCESSIVE HEAT HAZARD AREAS. BASED ON THESE SAME
OBJECTIVE TOOLS, A SLIGHT RISK OF EXCESSIVE HEAT ALSO APPLIES TO THE CENTRAL
VALLEY OF CALIFORNIA, AUG 2-8, WHERE HEAT INDEX VALUES MAY APPROACH OR EXCEED
110 DEG F.
THE SUBTROPICAL RIDGE IS PREDICTED TO BE CENTERED OVER THE FOUR CORNERS REGION
DURING WEEK-2, IN ITS CLIMATOLOGICAL POSITION DURING THE SUMMER MONSOON SEASON.
THE 06Z AND 12Z DETERMINISTIC GFS RUNS ARE PREDICTING TWO TROPICAL CYCLONES
OVER THE EASTERN PACIFIC DURING THE OUTLOOK PERIOD, WHICH PASS SOUTH OF THE
GULF OF CALIFORNIA. ONE OF THESE SYSTEMS COULD TRIGGER A GULF SURGE OF MOISTURE
INTO THE AMERICAN SOUTHWEST, WITH THE PET PRECIPITATION TOOL DEPICTING AMOUNTS
OF ABOUT 0.5-INCH. HOWEVER, NO PRECIPITATION HAZARD IS POSTED AT THIS TIME.
THE HEAVIEST PRECIPITATION AMOUNTS PREDICTED DURING THIS OUTLOOK PERIOD RANGE
FROM 1-2 INCHES OVER A 3-DAY PERIOD, FOCUSED ALONG THE SOUTHEAST AND GULF
COASTS. HOWEVER, NORMAL WEEKLY PRECIPITATION AMOUNTS FOR THOSE AREAS RANGE FROM
1.0-1.5 INCHES IN MOST AREAS TO ALMOST 2 INCHES ALONG THE GULF COAST OF
FLORIDA. THEREFORE, NO PRECIPITATION HAZARDS ARE DEPICTED ON TODAY’S HAZARDS
MAP. HOWEVER, ACCORDING TO THE EXPERIMENTAL FLOOD HAZARD OUTLOOK, THIS AMOUNT
OF PRECIPITATION IS ENOUGH TO RENEW FLOODING CHANCES ACROSS THE EASTERN COASTAL
REGION OF NORTH CAROLINA, WHICH RECENTLY EXPERIENCED HEAVY PRECIPITATION AND
HAS ELEVATED SOIL MOISTURE ANOMALIES.
THE COMBINATION OF CONTINUED ABOVE-NORMAL TEMPERATURES AND BELOW-NORMAL
PRECIPITATION SUPPORTS THE CONTINUATION AND NOW EXPANSION OF A RAPID ONSET
DROUGHT (ROD) RISK FROM MOST OF THE NORTHERN AND CENTRAL PLAINS INTO WESTERN
MISSOURI. DRY SOILS, STRESSED VEGETATION, AND REDUCED WATER AVAILABILITY DUE TO
LOW PONDS AND STREAMS MAY LEAD TO INCREASED IMPACTS TO AGRICULTURE AND
LIVESTOCK, WITH SOME LOCATIONS ALREADY EXPERIENCING IMPACTS.
NO HAZARDS ARE POSTED FOR ALASKA DURING WEEK-2. HOWEVER, THERE IS A SIGNIFICANT
CHANCE OF ACCUMULATING SNOW FOR PORTIONS OF THE CENTRAL AND EASTERN BROOKS
RANGE, WHICH COULD HAVE AN IMPACT ON PEOPLE WITHIN THAT AREA. THIS POSSIBILITY
WILL BE REASSESSED TOMORROW AFTER LOOKING AT THE MOST RECENT MODEL SOLUTIONS.
NEAR JUNEAU, LOCALIZED FLOODING MAY BE A CONCERN ASSOCIATED WITH THE GLACIAL
OUTBURST FLOOD FOR THE MENDENHALL RIVER.
FORECASTER: ANTHONY ARTUSA
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