756  
FXUS02 KWBC 281900  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EDT SUN AUG 28 2022  
 
VALID 12Z WED AUG 31 2022 - 12Z SUN SEP 04 2022  
   
..OVERVIEW
 
 
AN AMPLIFIED FLOW PATTERN IS EXPECTED TO START THE FORECAST PERIOD  
MIDWEEK, FEATURING STRONG RIDGING THROUGH THE INTERIOR WEST WITH  
DEEPER TROUGHING ACROSS THE EASTERN PACIFIC AS WELL AS THE GREAT  
LAKES INTO THE NORTHEAST U.S., THE LATTER OF WHICH HELPS DRIVE A  
COLD FRONT ACROSS MUCH OF THE CENTRAL TO EASTERN U.S. MID TO LATE  
WEEK. DRIER AND EARLY FALL-LIKE TEMPERATURES CAN BE EXPECTED IN  
ITS WAKE FROM THE UPPER MIDWEST TO THE EAST COAST WHILE THE WEST  
IS LIKELY TO SEE MUCH ABOVE NORMAL TEMPERATURES. THE COLD FRONT IS  
FORECAST TO SETTLE ALONG THE SOUTHERN TIER OF THE U.S. FROM THE  
TEXAS GULF COAST EASTWARD TO FLORIDA LATE IN THE WEEK INTO NEXT  
WEEKEND, AND THIS WILL BE FOCUS FOR SCATTERED TO NUMEROUS SHOWERS  
AND THUNDERSTORMS EACH DAY, SOME OF WHICH COULD PRODUCE LOCALLY  
HEAVY RAINFALL.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE AMPLIFIED PATTERN AT THE BEGINNING OF THE PERIOD CONTINUES TO  
PROMOTE GOOD MODEL AGREEMENT AND RUN TO RUN CONSISTENCY WITH THE  
OVERALL PATTERN FOR THE FIRST HALF OF THE MEDIUM RANGE PERIOD, AS  
THE UPPER HIGH HOVERS AROUND THE CENTRAL GREAT BASIN WITH THE  
AMPLIFIED RIDGE TO THE NORTH POTENTIALLY SHIFTING SLOWLY EAST AS  
THE EASTERN PACIFIC TROUGH DIGS, AND THE GREAT LAKES TROUGH BEGINS  
TO FLATTEN OUT SOMEWHAT. AT THE SURFACE, THE MAIN COLD FRONT SHOWS  
GOOD AGREEMENT WITH ITS TIMING AS IT TRACKS ACROSS THE CENTRAL AND  
EASTERN U.S. AND THEN SETTLES INTO THE GULF COAST STATES. THUS THE  
FIRST HALF OF THE MEDIUM RANGE FORECAST PERIOD CONSISTED OF A  
DETERMINISTIC MODEL BLEND FAVORING THE 00/06Z GFS AND 00Z ECMWF  
ALONG WITH LESSER PROPORTIONS OF THE 00Z CMC AND UKMET. BY DAY  
5/FRIDAY INTO THE WEEKEND, A COUPLE MAIN AREAS OF MODEL  
DIFFERENCES ARISE--A WEAKNESS IN THE RIDGE IN THE SOUTH-CENTRAL  
U.S. THAT SHOULD SUPPORT UNSETTLED WEATHER ACROSS TEXAS, AND THE  
TIMING OF A SHORTWAVE COMING INTO THE NORTHWEST AND TRACKING EAST.  
NO CLEAR OUTLIERS WERE SEEN WITH THE FORMER, WHILE WITH THE LATTER  
THE 00Z CMC SEEMED TO BE ON THE SLOWER END OF CONSENSUS, AND THE  
06Z GFS AND THE 00Z EC WERE MORE AGREEABLE WITH A FASTER  
TRACK--ALSO SUPPORTED BY THE INCOMING 12Z MODEL GUIDANCE SUITE.  
THE LATTER PART OF THE WPC FORECAST INCORPORATED SOME GEFS AND EC  
ENSEMBLE MEAN GUIDANCE WITH THE DETERMINISTICS TO SMOOTH OUT MODEL  
DIFFERENCES, AND THE RESULTING FORECAST MAINTAINED WPC CONTINUITY  
WELL.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
A COLD FRONT SWEEPING ACROSS THE CENTRAL TO EASTERN U.S. MID TO  
LATE WEEK WILL BE THE MAIN SENSIBLE WEATHER FEATURE OF NOTE ACROSS  
THE CONUS. AHEAD OF IT, ENOUGH WARM AND MOIST AIR WILL LIFT  
NORTHWARD TO SUPPORT SCATTERED TO NUMEROUS SHOWERS AND  
THUNDERSTORMS, SOME OF WHICH COULD BE LOCALLY HEAVY ACROSS  
PORTIONS OF NEW ENGLAND ON WEDNESDAY WHERE THE SYSTEM WILL HAVE  
BETTER DYNAMICS/LIFT TO SUPPORT MORE ORGANIZED CONVECTION. FARTHER  
SOUTH ALONG THE SOUTHWARD MOVING BOUNDARY, BETTER INSTABILITY AND  
MOISTURE ACROSS THE SOUTHERN PLAINS AND POTENTIALLY ALONG THE  
FLORIDA GULF COAST COULD SUPPORT INTENSE RAIN RATES AND LOCALIZED  
HEAVY RAINFALL. THE FRONT THEN IS EXPECTED TO SETTLE ACROSS THE  
SOUTHERN TIER OF THE U.S. AND WILL BE THE FOCUS FOR DAILY SHOWERS  
AND THUNDERSTORMS, SOME OF WHICH COULD BE LOCALLY HEAVY THROUGH  
NEXT WEEKEND ACROSS TEXAS EASTWARD ALONG THE GULF COAST.  
ELSEWHERE, THE REST OF THE COUNTRY LOOKS TO BE MAINLY DRY ASIDE  
FROM LIGHT RAIN CHANCES ACROSS CENTRAL PARTS OF THE ROCKIES/PLAINS  
AND A FRONTAL PASSAGE POSSIBLY CLIPPING THE PACIFIC NORTHWEST  
BRINGING GENERALLY LIGHT PRECIPITATION.  
 
THE GREATEST TEMPERATURE ANOMALIES THROUGH THE PERIOD WILL BE  
FOUND ACROSS THE WESTERN U.S. MID TO LATE WEEK, PARTICULARLY  
ACROSS THE NORTHWEST INTO NORTHERN PORTIONS OF THE ROCKIES/HIGH  
PLAINS, WHERE HIGHS COULD REACH 10-20F ABOVE NORMAL, WHILE 10-15F  
ABOVE NORMAL TEMPERATURES ARE POSSIBLE FOR THE GREAT BASIN AND  
CALIFORNIA. DAILY RECORDS COULD BE SET IN THE WEST WITH THE  
POSSIBILITY TO FLIRT WITH MONTHLY RECORDS AS WELL. 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. AS  
THE UPPER FLOW PATTERN BECOMES MORE ZONAL NEXT WEEKEND, THE ABOVE  
NORMAL TEMPERATURES LOOK TO SPREAD ACROSS MUCH OF THE NORTHERN  
TIER OF THE U.S. WITH HIGHS NEXT WEEKEND POSSIBLY 5-10F ABOVE  
NORMAL. CONVERSELY, THE SOUTHERN U.S. IS LIKELY TO SEE NEAR OR  
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE PERIOD,  
PARTICULARLY THE SOUTHERN PLAINS AND GULF COAST WHERE WIDESPREAD  
CLOUDS AND PRECIPITATION LOOK TO KEEP TEMPERATURES IN CHECK.  
 
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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