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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