282  
FXUS02 KWBC 020658  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
257 AM EDT FRI SEP 2 2022  
 
VALID 12Z MON SEP 5 2022 - 12Z FRI SEP 9 2022  
 
***PROLONGED HEAT WAVE FOR PORTIONS OF THE WESTERN U.S. INTO EARLY  
NEXT WEEK***  
 
   
..GENERAL OVERVIEW
 
 
THE MAIN WEATHER HEADLINE GOING INTO NEXT WEEK WILL CONTINUE TO BE  
THE ANOMALOUS UPPER LEVEL RIDGE THAT WILL BE ANCHORED ACROSS THE  
WESTERN U.S., AND THUS A CONTINUANCE OF THE ONGOING HEAT WAVE FROM  
THE WEST COAST TO THE NORTHERN PLAINS. SOME GOOD NEWS IS  
POTENTIALLY ON THE WEATHER HORIZON AS A STRONG SHORTWAVE TROUGH  
TRIES TO BREAK DOWN THE RIDGE ACROSS THE PACIFIC NORTHWEST AND  
SUPPRESSES THE RIDGE SOME. ACROSS THE EASTERN U.S., A BROAD UPPER  
TROUGH WILL LIKELY BE IN PLACE FOR THE BEGINNING OF THE WEEK THAT  
SHOULD WEAKEN WITH TIME, AND MOISTURE FROM A POSSIBLE TROPICAL  
DISTURBANCE MAY BEGIN APPROACHING THE SOUTHWESTERN U.S. BY THE END  
OF THE WEEK.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE 00Z MODEL GUIDANCE SUITE INITIALLY HAS A GOOD OVERALL SYNOPTIC  
SCALE DEPICTION OF THE OVERALL PATTERN ON MONDAY. BY MID WEEK,  
TIMING DIFFERENCES ARE APPARENT WITH THE ARRIVAL OF THE PACIFIC  
NORTHWEST TROUGH THAT WILL EVENTUALLY ERODE THE UPPER RIDGE ACROSS  
THE WESTERN U.S., WITH THE GFS INDICATING A SLOWER ARRIVAL.  
TOWARDS THE END OF THE WEEK, THE GFS IS MORE ROBUST WITH THE UPPER  
RIDGE OVER THE PLAINS, WHEREAS THE ECWMF AND CMC BREAK IT DOWN  
FASTER. TAKING THESE FACTORS INTO ACCOUNT, THE WPC  
FRONTS/PRESSURES FORECAST WAS PRIMARILY DERIVED FROM A MULTI-MODEL  
CONSENSUS THROUGH EARLY TUESDAY, FOLLOWED BY A GRADUAL INCREASE OF  
THE ENSEMBLE MEANS TO ACCOUNT FOR INCREASING MESOSCALE  
UNCERTAINTIES BY THE MIDDLE TO END OF THE WEEK.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
IT WILL CONTINUE TO BE VERY HOT BY EARLY SEPTEMBER STANDARDS  
ACROSS MOST OF THE WESTERN U.S. AND EXTENDING ACROSS MUCH OF THE  
NORTHERN PLAINS AND EVEN INTO THE UPPER MIDWEST THROUGH THE MIDDLE  
OF THE WEEK. AFTERNOON HIGHS ARE EXPECTED TO BE ON THE ORDER OF  
10-20 DEGREES ABOVE AVERAGE, AND THE SAME HOLDS TRUE FOR OVERNIGHT  
LOW, PROVIDING ONLY LIMITED RESPITE FROM THE HEAT. THIS WILL  
EQUATE TO HIGHS 110-115 DEGREES FOR THE LOWER ELEVATIONS OF THE  
DESERT SOUTHWEST, AND WIDESPREAD 90S FOR THE INTERMOUNTAIN WEST  
AND EXTENDING NORTHEAST ACROSS MONTANA AND THE DAKOTAS. MULTIPLE  
DAILY RECORDS WILL LIKELY BE EXCEEDED. ANOTHER FACTOR TO CONSIDER  
IS THE DURATION OF THE HEAT WAVE SINCE IT WILL BE VERY HOT FOR THE  
UPCOMING LABOR WEEKEND AS WELL. THIS WILL INCREASE HEAT STRESS  
FOR THOSE WORKING OUTDOORS AND FOR THOSE WITHOUT AIR CONDITIONING.  
IT IS INTERESTING TO NOTE THERE WILL LIKELY BE VERY LITTLE IN THE  
WAY OF BELOW AVERAGE LOW TEMPERATURES ANYWHERE ACROSS THE  
CONTINENTAL U.S. NEXT WEEK, ALTHOUGH HIGHS MAY RUN SEVERAL DEGREES  
BELOW AVERAGE ACROSS PORTIONS OF THE SOUTH AND GULF COAST REGION  
OWING TO INCREASED CLOUDS AND RAINFALL.  
 
IN TERMS OF RAINFALL, A QUASI-STATIONARY FRONTAL BOUNDARY DRAPED  
ACROSS THE SOUTHERN TIER STATES, WITH WAVES OF LOW PRESSURE ALONG  
IT, WILL BE THE GENERAL FOCUS FOR MULTIPLE ROUNDS OF SHOWERS AND  
THUNDERSTORMS. THIS IS EXPECTED TO EXTEND FROM TEXAS AND DEEP  
SOUTH, TO THE APPALACHIANS AND MID-ATLANTIC/NORTHEAST. THE  
TROPICS ARE ALSO EXPECTED TO BECOME MORE ACTIVE BY THE END OF THE  
WEEK WITH A POSSIBLE DISTURBANCE MOVING INLAND ACROSS WESTERN  
MEXICO AND POTENTIALLY BRINGING A SURGE OF MOISTURE NORTHWARD TO  
NEW MEXICO AND TEXAS LATE IN THE PERIOD, ALTHOUGH THIS REMAINS  
QUITE UNCERTAIN AT THIS JUNCTURE. ANOTHER TROPICAL DISTURBANCE  
COULD ALSO ENTER THE WESTERN ATLANTIC EAST OF THE BAHAMAS BY THE  
MIDDLE TO END OF THE WEEK, BASED ON RECENT NATIONAL HURRICANE  
CENTER OUTLOOKS.  
 
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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