957  
FXUS02 KWBC 300658  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
257 AM EDT SAT JUL 30 2022  
 
VALID 12Z TUE AUG 2 2022 - 12Z SAT AUG 6 2022  
 
***HEAT WAVE EXPECTED FROM THE NORTHERN PLAINS TO THE NORTHEAST  
NEXT WEEK***  
 
   
..GENERAL OVERVIEW
 
 
A WELCOMED PATTERN CHANGE IS FORECAST FOR THE NORTHWESTERN U.S.  
EARLY NEXT WEEK AS AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT  
HERALD A RETURN TO MUCH MORE PLEASANT TEMPERATURES. THE RIDGE  
AXIS AND THE ACCOMPANYING HEAT WAVE WILL PROGRESS FROM THE  
CENTRAL/NORTHERN PLAINS TO THE GREAT LAKES/NORTHEAST BY THURSDAY.  
BY THE END OF THE WEEK, A SECOND TROUGH IS LIKELY ACROSS THE  
PACIFIC NORTHWEST AND NORTHERN ROCKIES, WITH A DOWNSTREAM RIDGE  
ENCOMPASSING MUCH OF THE CENTRAL AND EASTERN U.S. WITH WIDESPREAD  
HOT AND HUMID WEATHER EXPECTED.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE 00Z MODEL GUIDANCE SUITE IS INITIALLY IN GOOD OVERALL SYNOPTIC  
SCALE AGREEMENT ACROSS THE CONTINENTAL U.S. ON TUESDAY, AND THE  
MODELS ARE A LITTLE MORE IN LINE ACROSS THE PACIFIC NORTHWEST  
COMPARED TO SIMILAR TIME SCALES YESTERDAY. THE MODELS HAVE ALSO  
COME IN BETTER FOCUS ON A SECOND AND REINFORCING TROUGH ARRIVING  
FROM WESTERN CANADA BY THURSDAY/FRIDAY ACROSS THE NORTHWEST, WITH  
THE GFS MORE PROGRESSIVE WITH THAT FEATURE AS IT TRACKS ACROSS THE  
NORTHERN TIER STATES. THE WPC FORECAST WAS DERIVED FROM A  
CMC/GFS/ECMWF BLEND AS A STARTING POINT THROUGH WEDNESDAY, AND  
THEN GRADUALLY INCREASED PERCENTAGES OF THE ECENS AND GEFS MEANS  
WHILE STILL MAINTAINING SOME GFS/ECMWF AND SLIGHTLY LESS CMC.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
ANOTHER HEAT WAVE IS EXPECTED TO MAKE WEATHER HEADLINES ON TUESDAY  
ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST FOR TUESDAY AND  
WEDNESDAY, WITH HIGHS RUNNING ON THE ORDER OF 15-20 DEGREES ABOVE  
AVERAGE, POTENTIALLY SETTING SOME DAILY RECORDS. THE HEAT THEN  
REACHES THE GREAT LAKES, OHIO VALLEY, AND THEN THE EAST COAST FOR  
LATER IN THE WEEK AS THE MONTH OF AUGUST BEGINS HOT AND HUMID.  
HEAT INDICES MAY EXCEED 105 DEGREES FOR SOME AREAS. MEANWHILE,  
TEMPERATURES WILL LIKELY BE NEAR TO SLIGHTLY BELOW NORMAL ACROSS  
MUCH OF THE WESTERN U.S., WITH THE COOLEST READINGS OVER  
WASHINGTON AND OREGON.  
 
IN TERMS OF PRECIPITATION, THERE WILL LIKELY BE SOME ABATEMENT IN  
THE COVERAGE OF HEAVY RAINFALL ACROSS MUCH OF THE NATION WITH NO  
SLIGHT RISK AREAS OF EXCESSIVE RAINFALL FOR TUESDAY AND WEDNESDAY.  
THERE WILL STILL BE PLENTY OF MONSOONAL MOISTURE IN PLACE ACROSS  
THE SOUTHWESTERN U.S., BUT NOT TO THE EXTENT THAT HAS BEEN  
OBSERVED RECENTLY. HOWEVER, THIS MAY INCREASE AGAIN GOING INTO  
FRIDAY AND NEXT SATURDAY WITH A GREATER COVERAGE OF SHOWERS AND  
STORMS. THERE MAY ALSO BE A ROUND OF HEAVY SHOWERS AND STRONG  
THUNDERSTORMS ACROSS PORTIONS OF THE GREAT LAKES AND THE NORTHEAST  
AHEAD OF A COLD FRONT TOWARDS THE END OF THE WEEK.  
 
HAMRICK  
 
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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