918
FXUS21 KWNC 222008
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 22 2024
SYNOPSIS: A BROAD AREA OF MID-LEVEL HIGH PRESSURE IS PREDICTED ACROSS MOST OF
THE LOWER 48 STATES DURING WEEK-2. THIS CORRESPONDS TO A SIGNIFICANT INCREASE
IN THE PREDICTED MAGNITUDE AND SPATIAL COVERAGE OF HEAT SIGNALS FOR LATE JULY
AND EARLY AUGUST. IN ALASKA, MID-LEVEL LOW PRESSURE IS FORECASTED ACROSS MOST
OF THE STATE, WITH THE EXCEPTION OF MID-LEVEL HIGH PRESSURE OVER THE ALEUTIAN
ARCHIPELAGO.
HAZARDS
MODERATE RISK OF EXCESSIVE HEAT FOR THE LOWER GREAT LAKES REGION, NORTHEAST,
AND UPPER MID-ATLANTIC, TUE-WED, JUL 30-31.
MODERATE RISK OF EXCESSIVE HEAT FOR THE NORTHERN AND CENTRAL PLAINS AS FAR
SOUTH AS THE TEXAS PANHANDLE, TUE-FRI, JUL 30-AUG 2.
SLIGHT RISK OF EXCESSIVE HEAT FOR THE INTERIOR WEST, MOST OF THE GREAT PLAINS,
AND FROM UPPER AND MIDDLE PORTIONS OF THE MISSISSIPPI VALLEY GENERALLY EASTWARD
TO THE ATLANTIC COAST FROM VIRGINIA NORTHWARD TO MAINE, TUE-MON, JUL 30-AUG 5.
RAPID ONSET DROUGHT RISK FOR PORTIONS OF THE NORTHERN AND CENTRAL PLAINS.
DETAILED SUMMARY
FOR THURSDAY JULY 25 - MONDAY JULY 29:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY JULY 30 - MONDAY AUGUST 05: FOR THE WEEK-2 PERIOD, MID-LEVEL
TROUGHS ARE PREDICTED BY THE GEFS, ECENS, AND CMCE ENSEMBLES JUST OFF THE WEST
COAST OF THE CONTIGUOUS U.S. (CONUS), AND OVER THE EASTERN STATES. FOR THE
MAJORITY OF THE CONUS, HOWEVER, ENSEMBLE MEANS FAVOR RIDGING AND POSITIVE
HEIGHT DEPARTURES. MID-TROPOSPHERIC HEIGHTS OF AT LEAST 5940 M ARE PREDICTED
ACROSS MOST OF THE SOUTHWESTERN AND SOUTH-CENTRAL STATES.
THE WEEK-2 TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL TEMPERATURES OVER ALMOST ALL
OF THE CONUS, WITH A SLIGHT RISK OF EXCESSIVE HEAT DEPICTED ACROSS MOST OF THE
LOWER 48 STATES OUTSIDE OF THE SOUTHEASTERN QUARTER OF THE NATION, AND VALID
FOR THE ENTIRE OUTLOOK PERIOD. THERE ARE TWO EMBEDDED REGIONS WHERE A MODERATE
RISK FOR EXCESSIVE HEAT IS FAVORED. ONE AREA INCLUDES THE LOWER GREAT LAKES
REGION, NORTHEAST, AND UPPER MID-ATLANTIC, JUL 30-31, WHILE THE SECOND, LARGER
AREA INCLUDES MOST OF THE GREAT PLAINS REGION, EXCLUDING CENTRAL AND SOUTHERN
TEXAS, JUL 30-AUG 2. IN THE NORTHEAST, HEAT INDEX VALUES MAY SURPASS 100 DEG F
ACROSS THE I-95 CORRIDOR FROM BOSTON AND NEW YORK CITY TO WASHINGTON, D.C. AND
RICHMOND, AND MAY SURPASS 110 DEG F ACROSS KANSAS AND OKLAHOMA DURING THE
SPECIFIED PERIODS. THIS IS INDICATED BY A SKILL-WEIGHTED, BIAS-CORRECTED HYBRID
HEAT INDEX FORECAST THAT USES THE GEFS AND ECENS MODELS. THE OVERALL,
BROAD-SCALE TEMPERATURE PATTERN IS CONSISTENT WITH RAW ENSEMBLE MEAN
TEMPERATURES FROM THE THREE ENSEMBLE MEAN MODELS.
ACROSS THE SOUTHWEST, THE SUBTROPICAL RIDGE AXIS IS PREDICTED TO SHIFT
SOUTHWARD DURING WEEK-2. THIS PATTERN IS TYPICALLY ASSOCIATED WITH
SIGNIFICANTLY DRIER CONDITIONS ACROSS THE MONSOON REGION, REPRESENTING A
NOTICEABLE CHANGE FROM RECENT WEEKS OF ENHANCED THUNDERSTORM ACTIVITY AND AREAS
OF MONSOON-RELATED FLASH FLOODING.
THE HEAVIEST PRECIPITATION AMOUNTS PREDICTED DURING THIS OUTLOOK PERIOD RANGE
FROM 1.0-1.5 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 ACROSS THE EASTERN COASTAL REGION
OF NORTH CAROLINA, WHICH RECENTLY EXPERIENCED HEAVY PRECIPITATION AND HAS
ELEVATED SOIL MOISTURE.
THE COMBINATION OF CONTINUED ABOVE-NORMAL TEMPERATURES AND BELOW-NORMAL
PRECIPITATION SUPPORTS THE CONTINUATION OF A RAPID ONSET DROUGHT (ROD) RISK
OVER MANY PARTS OF THE NORTHERN AND CENTRAL HIGH PLAINS. 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. NEAR JUNEAU HOWEVER, LOCALIZED
FLOODING MAY BE A CONCERN ASSOCIATED WITH THE GLACIAL OUTBURST FLOOD FOR THE
MENDENHALL RIVER.
FORECASTER: ANTHONY ARTUSA
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