809  
FXUS02 KWBC 271759  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
159 PM EDT SAT AUG 27 2022  
 
VALID 12Z TUE AUG 30 2022 - 12Z SAT SEP 03 2022  
   
..OVERVIEW
 
 
THE MID TO UPPER LEVEL PATTERN OVER THE CONUS IS EXPECTED TO  
REMAIN AMPLIFIED NEXT WEEK INTO EARLY NEXT WEEKEND, FEATURING A  
STRONG RIDGE THROUGH THE INTERIOR WEST WITH TROUGHING ACROSS THE  
EASTERN PACIFIC AND PORTIONS OF THE NORTHEASTERN QUADRANT OF THE  
CONUS. A SWEEPING COLD FRONT WILL MOVE ACROSS MUCH OF THE CENTRAL  
TO EASTERN U.S. TUESDAY-THURSDAY AND LINGERING NEAR THE GULF COAST  
LATE WEEK, USHERING IN DRIER CONDITIONS AND MORE FALL-LIKE  
TEMPERATURES TO PORTIONS OF THE EASTERN CONUS. MEANWHILE, WARM AND  
DRY CONDITIONS ARE EXPECTED FOR THE WEST, WITH SOME HIGH  
TEMPERATURE RECORDS POSSIBLE ACROSS THE NORTHWEST IN PARTICULAR.  
THE GREATEST PRECIPITATION COVERAGE AND AMOUNTS ARE EXPECTED TO BE  
TIED TO THE FRONTAL PASSAGE ACROSS THE CENTRAL AND EASTERN U.S.,  
WITH SOME MODERATE TO LOCALLY HEAVY RAINFALL POSSIBLE IN THE  
NORTHEAST TUESDAY-WEDNESDAY AND ACROSS THE GULF COAST STATES  
THROUGH MUCH OF THE WEEK.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODEL GUIDANCE CONTINUES TO SHOW AVERAGE TO ABOVE AVERAGE  
AGREEMENT AND CONSISTENCY WITH THE AMPLIFIED LARGE SCALE PATTERN  
CONSISTING OF THE UPPER TROUGH AXIS TRACKING FROM THE GREAT LAKES  
REGION TOWARDS THE NORTHEAST AND DEAMPLIFYING THROUGH THE PERIOD,  
WHILE AN UPPER HIGH DRIFTS OVER THE INTERIOR WEST AND EASTERN  
PACIFIC TROUGHING LINGERS UPSTREAM. THE EASTERNMOST TROUGH WILL  
PUSH A COLD FRONT THROUGH THE CENTRAL AND EASTERN U.S. BEFORE IT  
SETTLES ALONG THE GULF COAST. THE NORTHERN PART OF THE FRONT HAS  
CONTINUED ITS TREND A BIT FASTER COMPARED TO THE PREVIOUS  
FORECAST, LEADING TO A FASTER MOVEMENT OF THE RAIN AXIS ALONG AND  
AHEAD OF THE FRONT AND LOWER OVERALL PRECIPITATION FORECAST FOR  
THE NORTHEAST. THE EARLY PART OF THE WPC MEDIUM RANGE FORECAST WAS  
BASED ON A BLEND OF THE DETERMINISTIC 00Z/06Z GFS AND 00Z  
ECMWF/CMC/UKMET, GIVEN THE GOOD OVERALL MODEL AGREEMENT.  
 
BY LATE NEXT WEEK, THE DETAILS OF THE PATTERN BECOME A LITTLE MORE  
NEBULOUS AS A WEAKNESS IN THE UPPER RIDGE IS FORECAST, WITH ENERGY  
LIKELY SOMEWHERE IN THE CENTRAL U.S. BREAKING UP WESTERN AND  
EASTERN UPPER HIGHS, BUT WITH CONSIDERABLE VARIABILITY AMONG  
MODELS. THERE ARE ALSO SOME TIMING AND AMPLITUDE DIFFERENCES WITH  
A SHORTWAVE THAT COULD ENTER THE PACIFIC NORTHWEST AROUND FRIDAY.  
OVERALL THESE DIFFERENCES ARE SOMEWHAT TYPICAL FOR DAY 6-7  
FORECASTS, SO THE WPC FORECAST GRADUALLY PHASED TOWARD A BLEND OF  
ABOUT HALF GEFS AND EC ENSEMBLE MEANS AND HALF DETERMINISTIC  
MODELS BY DAY 7, WHICH MAINTAINED CONTINUITY FAIRLY WELL.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
THE MAIN WEATHER FEATURE THROUGH THE PERIOD WILL BE A COLD FRONT  
THAT PROGRESSES ACROSS THE CENTRAL TO EASTERN U.S. MID TO LATE  
WEEK. AHEAD OF THAT FEATURE, ENOUGH WARM AND MOIST AIR WILL  
SUPPORT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS, SOME OF  
WHICH COULD BE LOCALLY HEAVY. THE GREATEST CHANCES FOR SEEING A  
FEW STRONGER STORMS AND LOCALLY HEAVY RAINFALL LOOK TO BE ACROSS  
THE EASTERN GREAT LAKES INTO THE NORTHEAST TUESDAY-WEDNESDAY TIED  
TO THE BETTER FORCING/LIFT WITH THE FRONTAL PASSAGE, AS WELL AS  
THE SOUTHERN PLAINS INTO THE MISSISSIPPI VALLEY WHERE THE BETTER  
INSTABILITY/MOISTURE WILL BE FOUND MID TO LATE WEEK AS THE FRONT  
LINGERS. THE WESTERN TO NORTH-CENTRAL U.S. IS EXPECTED TO BE  
MAINLY DRY, WITH THE EXCEPTION OF POSSIBLE SHOWERS IN CENTRAL AND  
SOUTHERN PORTIONS OF THE ROCKIES AND HIGH PLAINS BY THE LATTER  
HALF OF NEXT WEEK. ALSO, A FRONTAL PASSAGE MAY CLIP THE PACIFIC  
NORTHWEST BY LATE WEEK, BRINGING SOME PRECIPITATION TO THE  
OLYMPICS AND NORTHERN CASCADES.  
 
THE WARMEST TEMPERATURE ANOMALIES WILL BE FOUND ACROSS THE PACIFIC  
NORTHWEST INTO THE NORTHERN PLAINS NEXT WEEK, UNDERNEATH THE  
BUILDING UPPER RIDGE AND AHEAD OF A COLD FRONT THAT SLIPS THROUGH  
LATER IN THE WEEK. HIGHS COULD REACH 10-20F ABOVE NORMAL EACH OF  
THOSE DAYS, LEADING TO THE POSSIBILITY OF RECORD HIGHS. MEANWHILE,  
THE NORTHEAST WILL ALSO SEE ABOVE NORMAL TEMPERATURES ON TUESDAY  
AHEAD OF THE STRONGER COLD FRONT THAT IS SLATED TO SWEEP THROUGH  
MUCH OF THE CENTRAL AND EASTERN U.S., BRINGING IN SOME EARLY FALL  
SEASONABLE TEMPERATURES IN ITS WAKE. AS THE CALENDAR TURNS TO  
METEOROLOGICAL FALL, MUCH OF THE UPPER MIDWEST, GREAT LAKES, AND  
NORTHEAST SHOULD SEE AT OR SLIGHTLY BELOW NORMAL HIGHS, WITH COOL  
LOWS IN THE 40S TO 50S IN PORTIONS OF THOSE AREAS. HIGH  
TEMPERATURES IN PARTICULAR ARE ALSO EXPECTED TO BE BELOW AVERAGE  
FOR THE SOUTHERN PLAINS TOWARD THE LOWER MISSISSIPPI VALLEY WITH  
THE FRONT AND RAIN/CLOUDINESS IN THE VICINITY.  
 
TATE/TAYLOR  
 
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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