367  
FXUS02 KWBC 270650  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
249 AM 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 U.S.. A SWEEPING  
COLD FRONT WILL MOVE ACROSS MUCH OF THE CENTRAL TO EASTERN U.S.  
MID TO LATE WEEK, USHERING IN DRIER AND MORE FALL-LIKE  
TEMPERATURES TO PORTIONS OF THE EASTERN CONUS. MEANWHILE, WARM AND  
DRY CONDITIONS ARE EXPECTED FOR THE INTERIOR WEST INTO THE  
NORTHWEST WHERE A FEW DAILY TEMPERATURE RECORDS COULD BE  
CHALLENGED. 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.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
WITH THE MORE AMPLIFIED PATTERN, THE LATEST MODEL GUIDANCE SHOWED  
AVERAGE TO ABOVE AVERAGE AGREEMENT AND CONSISTENCY WITH THE LARGE  
SCALE PATTERN. THE DETERMINISTIC RUNS USED IN THE BLEND (18Z GFS,  
12Z ECMWF, 12Z UKMET, 12Z CMC) SHOWED FAIRLY STRONG AGREEMENT WITH  
THE SHORTWAVE TROUGH DEEPENING OVER THE GREAT LAKES WITH THE  
UPSTREAM RIDGE OVER THE INTERIOR WEST BUILDING NORTHWARD INTO THE  
CANADIAN ROCKIES AND A 594DM CENTER OVER THE FOUR CORNERS. THIS  
AMPLIFIED PATTERN NOW SUPPORTS THE COLD FRONT PASSAGE TO SWEEP  
MUCH OF THE CENTRAL TO EASTERN U.S. MID TO LATE WEEK, WITH THE  
SURFACE FRONT LIKELY TO SETTLE ALONG THE GULF COAST BEFORE WASHING  
OUT LATE NEXT WEEK INTO NEXT WEEKEND. TOWARD THE END OF THE WEEK  
INTO NEXT WEEKEND, A WEAKNESS IN THE UPPER RIDGE MAY FORM OVER THE  
SOUTHERN PLAINS TO LOWER MISSISSIPPI VALLEY IN COMBINATION WITH  
THE SURFACE FRONT SETTLING IN THE REGION. THIS COULD BE THE FOCUS  
FOR ADDITIONAL PRECIPITATION, ENHANCING TOTALS ALONG THE GULF  
COAST SOMEWHAT. THE WPC BLEND THIS CYCLE BEGAN WITH A NEAR EQUAL  
WEIGHTING OF THE LATEST AVAILABLE DETERMINISTIC GUIDANCE THEN  
TRANSITIONED INTO USING ABOUT 50 PERCENT OF ENSEMBLE MEANS (ECENS  
AND GEFS) AND 18Z GFS AND 12Z ECMWF MAKING UP THE OTHER HALF. THIS  
SEEMED TO ADJUST WELL TO THE LATEST MODEL TRENDS WHILE MAINTAINING  
CONTINUITY.  
 
   
..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 MID-WEEK 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. THE WEST IS  
EXPECTED TO BE MAINLY DRY THOUGH BY THE END OF THE WORK WEEK INTO  
NEXT WEEK, PRECIPITATION IS POSSIBLE ACROSS THE SOUTHERN ROCKIES  
AND HIGH PLAINS. A FRONTAL PASSAGE MAY CLIP THE PACIFIC NORTHWEST  
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. MEANWHILE, THE NORTHEAST WILL ALSO SEE MUCH 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 EVEN INTO THE PORTIONS OF THE SOUTH  
SHOULD SEE AT OR SLIGHTLY BELOW NORMAL HIGHS. LOWS IN THE 40S TO  
50S WILL BE FOUND ACROSS THE UPPER MIDWEST INTO THE INTERIOR  
NORTHEAST.  
 
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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