760  
FXUS02 KWBC 290659  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
258 AM EDT FRI JUL 29 2022  
 
VALID 12Z MON AUG 1 2022 - 12Z FRI AUG 5 2022  
 
***MAJOR HEAT WAVE LIKELY FROM THE NORTHERN PLAINS TO THE UPPER  
MIDWEST EARLY NEXT WEEK***  
 
***MONSOON REMAINS ACTIVE ACROSS THE SOUTHWESTERN U.S. WITH  
ADDITIONAL FLOODING POTENTIAL ON MONDAY***  
 
   
..OVERVIEW
 
 
A PATTERN CHANGE IS FORECAST TO EVOLVE ACROSS THE NORTHWESTERN  
U.S. FOR THE BEGINNING OF NEXT WEEK AS AN UPPER LEVEL TROUGH AND  
ASSOCIATED COLD FRONT BRING WELCOMED RELIEF FROM THE INTENSE HEAT  
WAVE EXPECTED IN THE SHORT RANGE PERIOD. THE UPPER RIDGE  
RESPONSIBLE FOR THIS HEAT WAVE SHOULD CROSS THE CENTRAL/NORTHERN  
PLAINS AND THEN THE MIDWEST GOING INTO THE MIDDLE OF THE WEEK, AND  
EVEN AFFECTING PARTS OF THE EAST COAST REGION BY THURSDAY. THE  
MONSOON IS EXPECTED TO REMAIN ACTIVE ACROSS THE FOUR CORNERS  
REGION WITH ADDITIONAL HEAVY SHOWERS AND STORMS AT TIMES.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODEL DIFFERENCES BECOME APPARENT AS EARLY AS MONDAY REGARDING THE  
PLACEMENT AND EVOLUTION OF THE TROUGH CROSSING THE PACIFIC  
NORTHWEST, WITH THE LATEST 00Z RUN OF THE GFS EAST OF THE  
CMC/ECMWF/ECENS, WHEREAS MODEL AGREEMENT IS GOOD ACROSS THE  
CENTRAL AND EASTERN U.S. FOR THIS TIME. FORECAST CONFIDENCE  
DECREASES TO BELOW AVERAGE BY THE WEDNESDAY TO FRIDAY TIME PERIOD  
AS THE WESTERN TROUGH INTRODUCES ADDITIONAL UNCERTAINTIES IN THE  
MODELS. THE 00Z ECMWF IS AT ODDS WITH THE GFS AND EVEN THE CMC  
ACROSS THE NORTHERN PLAINS FOR MID-WEEK, AND THIS OUT-OF-PHASE  
PROBLEM PERSISTS GOING INTO THE END OF THE WEEKEND ACROSS THE  
GREAT LAKES AND OHIO VALLEY REGION. THEREFORE, SIGNIFICANT  
ADJUSTMENTS TO THE FORECAST ARE LIKELY IN FUTURE UPDATES AS THE  
OVERALL MODEL SIGNAL BECOMES CLEARER. FOR THE WPC FORECAST, THERE  
WAS GOOD AGREEMENT AMONG THE GFS/UKMET THROUGH TUESDAY TO MERIT  
THEIR INCLUSION IN THE MODEL BLEND, AND THEN INCREASING THE  
WEIGHTING OF THE ENSEMBLE MEANS WHILE STILL MAINTAINING SOME OF  
THE 12Z ECMWF.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
THE HEAT WAVE IN THE NORTHWEST/GREAT BASIN IS FORECAST TO ABATE  
CONSIDERABLY GOING INTO MONDAY AND ESPECIALLY TUESDAY, WITH THE  
HEAT AXIS SHIFTING EAST AHEAD OF AN UPPER TROUGH APPROACHING THE  
PACIFIC NORTHWEST. EVENTUALLY, THE ANOMALOUS HEAT SHIFTS EAST  
ACROSS THE NORTHERN AND CENTRAL PLAINS THROUGH THE FIRST HALF OF  
NEXT WEEK, WHERE DAYTIME HIGHS COULD ONCE AGAIN APPROACH OR EXCEED  
100F IN MANY LOCATIONS. TEMPERATURES SHOULD ALSO BE ON THE RISE  
FROM THE OHIO VALLEY INTO THE NORTHEAST AS HEIGHTS BEGIN TO BUILD  
THROUGH THE MIDDLE TO END OF NEXT WEEK. MEANWHILE, SLIGHTLY ABOVE  
NORMAL HEAT AND HUMIDITY CONTINUES SOUTH OF A FRONTAL SYSTEM OVER  
THE NATION'S MID-SECTION, CONTINUING THE RECORD HOT SUMMER FOR  
MUCH OF THE SOUTHERN PLAINS AND SOUTHEAST THROUGH MUCH OF NEXT  
WEEK.  
 
HEAVY RAIN REMAINS A THREAT ACROSS PARTS OF THE CENTRAL AND  
SOUTHERN APPALACHIANS AND WESTERN FOOTHILLS, WHERE A SLIGHT RISK  
OF EXCESSIVE RAINFALL REMAINS FOR DAY 4. HOWEVER, THE LATEST  
INDICATIONS SUGGEST THE OVERALL RAINFALL INTENSITY SHOULD WANE  
AFTER SUNDAY, ALTHOUGH THE GROUND WILL BE HIGHLY SATURATED AND  
THUS VULNERABLE TO ANY ADDITIONAL RAINFALL. PERSISTENT MONSOONAL  
MOISTURE WILL CONTINUE TO SUPPORT DIURNALLY DRIVEN HEAVY SHOWERS  
AND STORMS WITH LOCALLY EXCESSIVE RAINFALL OVER AN ALREADY VERY  
SOGGY SOUTHWEST THROUGH THE MIDDLE OF NEXT WEEK.  
 
HAMRICK/JACKSON  
 
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC  
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, EXPERIMENTAL EXCESSIVE RAINFALL  
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES ARE  
AT:  
 
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML  
 

 
 

 
 
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