418  
FXUS02 KWBC 291741  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
140 PM EDT FRI JUL 29 2022  
 
VALID 12Z MON AUG 01 2022 - 12Z FRI AUG 05 2022  
 
***HIGH HEAT SWEEPS EAST FROM THE NORTHERN PLAINS TO THE NORTHEAST  
NEXT WEEK***  
 
   
..OVERVIEW
 
 
A PATTERN CHANGE WILL COME TO THE NORTHWESTERN U.S. EARLY NEXT  
WEEK IN THE FORM OF AN AN UPPER LEVEL TROUGH AND ASSOCIATED COLD  
FRONT WHICH BRING WELCOMED RELIEF FROM THE ONGOING HEAT WAVE  
THERE. THE NORTHERN SIDE OF THE UPPER RIDGE RESPONSIBLE FOR THIS  
HEAT WAVE IS FORECAST TO PUSH EAST ACROSS THE CENTRAL/NORTHERN  
PLAINS EARLY NEXT WEEK AND THEN THE UPPER MIDWEST/NORTHEAST FOR  
THE REST OF THE WEEK. THERE ARE SIGNS THE MONSOON WILL  
WEAKEN/BECOME MORE DIFFUSE AS THE UPPER RIDGE SHIFTS EAST NEXT  
WEEK.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
UNCERTAINTY REMAINS WITH THE UPPER LOW/TROUGH LINGERING NEAR THE  
PACIFIC NORTHWEST COAST EARLY NEXT WEEK. LIKE YESTERDAY, THE 12Z  
GFS/UKMET CONTINUED A SLOWING TREND OF THE TROUGH PROGRESSION  
INLAND, AND ARE NOW MORE IN LINE WITH THE 00Z CMC (PARTICULARLY  
AROUND TUESDAY) WHICH WAS CHOSEN AS THE COMPROMISE DETERMINISTIC  
MODEL IN THE FORECAST BLEND BETWEEN THE SLOW/CLOSED 00Z ECMWF AND  
THE PROGRESSIVE GFS/UKMET. THE POWERFUL RIDGE OVER THE  
NORTH-CENTRAL PACIFIC WILL CONTINUE TO FAVOR TROUGHING OVER THE  
NORTHWESTERN US AND THERE IS NOW DECENT AGREEMENT AMONG THE LATEST  
GLOBAL MODELS FOR A CLOSED LOW OVER THE BC COAST BY WEDNESDAY  
NIGHT. THIS PATTERN WOULD ALLOW A BROAD TROUGH OVER MUCH OF THE  
REST OF THE CONUS WITH SHORTWAVE ACTIVITY OVER THE GREAT  
LAKES/INTERIOR NORTHEAST BELOW THE GYRE STALLED NEAR HUDSON BAY.  
THE RESULTANT SHORTWAVE TROUGH FROM THE CLOSED LOW OFF THE PACIFIC  
NORTHWEST IS A KEY FEATURE TO TRACK IN FUTURE FORECASTS. FOR NOW,  
THE 00Z ECMWF WAS LIMITED IN THE FORECAST BLEND BY WEDNESDAY SINCE  
ITS TROUGH OVER THE NORTHWEST IS SO PROMINENT. ENSEMBLE MEANS FROM  
THE GEFS/CMCE/ECENS WERE FAVORED FOR WED-FRI (DAYS 5-7).  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
ANOMALOUS HEAT SHIFTS EAST ACROSS THE NORTHERN AND CENTRAL PLAINS  
TO THE GREAT LAKES THROUGH THE FIRST HALF OF NEXT WEEK, WHERE  
DAYTIME HIGHS OF 15-20 DEGREES ABOVE NORMAL LOOK TO ONCE AGAIN  
EXCEED 100F IN MANY LOCATIONS (THOUGH ONLY FOR A DAY AT ANY  
PARTICULAR LOCATION). TEMPERATURES THEN RISE RISE FROM THE OHIO  
VALLEY THROUGH THE NORTHEAST IN THE LATTER HALF OF THE WEEK AS  
HEIGHTS CONTINUE TO BUILD EAST. 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 NEXT WEEK.  
 
HEAVY RAIN REMAINS A THREAT INTO MONDAY FOR ALREADY WATER-LOGGED  
WESTERN PARTS OF THE CENTRAL AND SOUTHERN APPALACHIANS WHERE A  
SLIGHT RISK OF EXCESSIVE RAINFALL REMAINS FOR DAY 4. WHILE THE  
MONSOON REMAINS ACTIVE THROUGH NEXT WEEK, RECENT GUIDANCE SUGGESTS  
THE EASTWARD MOTION OF THE UPPER RIDGE BRINGS A MORE DIFFUSE FOCUS  
TO RAIN ACROSS THE SOUTHWEST FOR MONDAY THROUGH WEDNESDAY, THOUGH  
AREAS LESS AFFECTED RECENTLY SUCH AS CENTRAL NEVADA DO BECOME  
ACTIVE IN THIS PATTERN.  
 
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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