219  
FXUS02 KWBC 161814  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
213 PM EDT SAT JUL 16 2022  
 
VALID 12Z TUE JUL 19 2022 - 12Z SAT JUL 23 2022  
 
...DANGEROUS HEAT TO PERSIST OVER MUCH OF THE WESTERN AND  
ESPECIALLY CENTRAL U.S. NEXT WEEK...  
   
..OVERVIEW
 
 
HOT TEMPERATURES WILL PREVAIL ACROSS A LARGE AREA OF THE  
CENTRAL/WESTERN U.S. UNDERNEATH A STRONG UPPER RIDGE CENTERED OVER  
THE FOUR CORNERS REGION. NEAR OR RECORD HIGHS WILL BE POSSIBLE AT  
TIMES, AND VERY WARM MORNING LOWS MAY ALSO CHALLENGE DAILY RECORDS  
OVER SOME AREAS. TOWARD THE END OF NEXT WEEK AND THE WEEKEND A  
POTENTIAL EASTWARD SHIFT IN THE UPPER RIDGE AND ARRIVAL OF A WEAK  
PACIFIC TROUGH TO THE WEST COAST MAY BRING WESTERN U.S. HIGH  
TEMPERATURES CLOSER TO NORMAL. FLOW AROUND THE RIDGE WILL CARRY  
SHORTWAVES THAT WILL HELP TO REINFORCE THE LONG TERM MEAN TROUGH  
OVER THE NORTHEASTERN U.S. AND PRODUCE EPISODES OF SHOWERS AND  
THUNDERSTORMS FROM THE NORTHERN TIER INTO THE EAST. FOR THE  
SOUTHWEST U.S. INTO THE ROCKIES, SOME MONSOONAL MOISTURE UNDER THE  
RIDGE WILL PROVIDE DAILY CHANCES OF SHOWERS AND STORMS, SOME OF  
WHICH COULD LEAD TO FLASH FLOODING.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
FOR THIS FORECAST CYCLE, THE MODEL GUIDANCE REMAIN LARGELY  
AGREEABLE AND CONSISTENT GIVING WAY TO AVERAGE TO ABOVE AVERAGE  
FORECAST CONFIDENCE IN THE LARGE SCALE SYNOPTIC PATTERN. THE  
LATEST GUIDANCE IS CLUSTERED NICELY ON THE CENTER OF THE FOUR  
CORNERS UPPER RIDGE THROUGH ABOUT MID-WEEK WITH A STRONG, COMPACT  
UPPER LOW TRACKING ACROSS THE NORTHERN TIER / CANADIAN BORDER  
TOWARD THE GREAT LAKES. THE 00Z CMC WAS A SLOWER OUTLIER WITH THIS  
FEATURE THAT TRANSLATED THROUGH THE REST OF THE PERIOD AND AS A  
RESULT, ITS WEIGHT IN THE MODEL BLEND WAS CONSIDERABLY LOWER  
THOUGH WASN'T ENTIRELY DISCOUNTED GIVEN A SLIGHT SLOWING TREND  
OVERALL. OTHER ASPECTS OF THE FORECAST SHOW VARYING DEGREES OF  
SPREAD AND VARIABILITY. BY MID TO LATE WEEK, THE WESTERN U.S.  
TROUGH BEGINS TO PUSH ONSHORE WHERE THERE IS STILL SOME TIMING AND  
DEPTH ISSUES, WITH THE TYPICAL MODEL BIASES SHOWING UP. THE 06Z  
GFS (AND 12Z AS WELL) REMAIN A BIT FASTER COMPARED TO THE  
CONSENSUS WHILE THE 00Z (AND NOW 12Z) ECMWF SHOW SOME SLOWER  
PROGRESSION. BY THE END OF NEXT WEEK INTO NEXT WEEKEND, THE UPPER  
RIDGE OVER THE SOUTHWEST BEGINS TO SHIFT TO THE EAST AND FLATTEN  
OUT BUT THE CENTER AXIS REMAINS UNCERTAIN AMONG THE VARIOUS  
DETERMINISTIC MODELS. GIVEN SOME OF THE INCREASING MODEL SPREAD  
LATE NEXT WEEK INTO NEXT WEEKEND, THE FORECAST CYCLE THIS UPDATE  
INCORPORATED MOSTLY THE 00Z ECMWF/06Z GFS/00Z UKMET THROUGH DAY 5  
THEN NEARLY 50 PERCENT OF A ECENS/GEFS MEAN. THIS RESULTED IN A  
FORECAST WITH GOOD CONTINUITY OVERALL WITH ONLY TYPICAL RUN TO RUN  
DETAIL/TIMING ADJUSTMENTS.  
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
WHILE MUCH OF THE COUNTRY WILL SEE ABOVE NORMAL TEMPERATURES TO  
START THE PERIOD (TUESDAY JULY 19), THE GREATEST DEPARTURES FROM  
NORMAL WILL BE FOUND ACROSS THE PLAINS TO UPPER MIDWEST WHERE  
DAYTIME HIGHS 10 TO 15 DEGREES ABOVE NORMAL ARE EXPECTED. THIS  
PUTS TRIPLE DIGIT READINGS ACROSS THE SOUTHERN AND CENTRAL PLAINS  
AND 90S OVER A LARGE PERCENTAGE OF THE COUNTRY. SCATTERED DAILY  
RECORD HIGHS ARE POSSIBLE THROUGH THE WEEK WITH MORNING LOWS  
LIKELY TO CHALLENGE RECORDS AS WELL MID TO LATE WEEK. OVER THE  
WEST, MONSOONAL MOISTURE AND ASSOCIATED DIURNALLY FAVORED  
SHOWERS/STORMS WITH LOCALLY HEAVY RAINFALL MAY KEEP PARTS OF THE  
FOUR CORNERS/GREAT BASIN REGION CLOSE TO NORMAL FOR HIGHS THROUGH  
THE PERIOD. OTHER PARTS OF THE WEST INLAND FROM THE PACIFIC COAST  
SHOULD START THE PERIOD UP TO 5-10F ABOVE NORMAL FOR HIGHS BUT  
THEN DECLINE MORE TOWARD NORMAL AS AN UPPER LOW/SHORTWAVE EJECT  
FROM THE PACIFIC AND THE FOUR CORNERS UPPER HIGH EVENTUALLY SHIFTS  
EASTWARD. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE WITH A FAIRLY  
VIGOROUS SYSTEM FORECAST TO TRACK FROM THE NORTHERN PLAINS THROUGH  
THE GREAT LAKES AND EASTERN CANADA/NORTHEAST U.S. TUESDAY ONWARD.  
UNCERTAIN SPECIFICS OF ENERGY EJECTING FROM THE PACIFIC MAY PLAY A  
ROLE IN CONVECTIVE DETAILS ALONG A TRAILING FRONT THAT MAY SETTLE  
INTO THE FAR NORTHERN TIER LATE WEEK INTO THE WEEKEND. THE  
MID-ATLANTIC AND NORTHEAST WILL BE ON THE VERY WARM TO HOT SIDE,  
WITH SOME LOCATIONS POSSIBLY SEEING MORE CONSECUTIVE DAYS OF PLUS  
5-10F ANOMALIES FOR HIGHS THAN PREVIOUSLY EXPERIENCED SO FAR THIS  
SUMMER. PERSISTENT MOISTURE WILL ALLOW FOR MULTIPLE EPISODES OF  
SHOWERS/THUNDERSTORMS OVER THE SOUTHEAST/FLORIDA AND CENTRAL GULF  
COAST REGION. TEMPERATURES SHOULD BE NEAR NORMAL OVER THOSE AREAS.  
 
RAUSCH/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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