748  
FXUS02 KWBC 140651  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
250 AM EDT THU JUL 14 2022  
 
VALID 12Z SUN JUL 17 2022 - 12Z THU JUL 21 2022  
   
..HEAT THREAT TO LOOM OVER MUCH OF THE WESTERN AND CENTRAL U.S.
 
 
   
..PATTERN OVERVIEW AND WEATHER/HAZARDS HIGHLIGHTS
 
 
A HOT UPPER HIGH/RIDGE WILL SETTLE NEAR FOUR CORNERS TO SUPPORT  
HIGH HEAT ACROSS MUCH OF THE WEST WELL INTO NEXT WEEK, BUT  
PREDICTABILITY IS ALSO HIGH FOR WIDESPREAD HEAT TO ENCOMPASS  
ACROSS MUCH OF THE CENTRAL U.S. AS RIDGING/HEIGHTS BUILD  
DOWNSTREAM. SCATTERED LOCAL RECORD VALUES ARE POSSIBLE IN THESE  
BROAD AREAS. IN THIS PATTERN, MODERATING MONSOONAL MOISTURE FLOW  
ACROSS THE SOUTHWEST INTO THE CENTRAL GREAT BASIN/ROCKIES UNDER  
THE UPPER RIDGE WILL ALTERNATELY OFFER DAILY CHANCES FOR SHOWERS  
WITH SOME LOCALLY HEAVIER DOWNPOURS/RUNOFF ISSUES WITH SLOW CELL  
MOTIONS. MEANWHILE, A SERIES OF UNCERTAIN UPPER TROUGHS/IMPULSES  
WILL WORK INLAND FROM THE PACIFIC AND FROM SOUTHERN CANADA TO  
TRACK OVER-TOP THE RIDGE WITH ASSOCIATED FRONTAL SYSTEMS TO  
PERIODICALLY FOCUS PROGRESSIVE AND POTENTIALLY STRONG CONVECTION  
FROM THE NORTH-CENTRAL U.S. AND MIDWEST/GREAT LAKES TO THE EAST  
WHERE A MEAN UPPER TROUGH IS REINFORCED. DEEPER MOISTURE WILL ALSO  
FUEL SHOWERS/THUNDERSTORMS FARTHER SOUTHWARD DOWN ACROSS THE  
SOUTHEAST/FL AND CENTRAL GULF COAST STATES.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
WHILE THE OVERALL LARGER SCALE PATTERN EVOLUTION SEEMS REASONABLE  
IN GUIDANCE THROUGH MEDIUM RANGE TIME SCALES, MODEL EMBEDDED  
SYSTEM TIMING/STRENGTH DIFFERENCES IN THE 12/18 UTC GUIDANCE CYCLE  
WERE NOTABLE ALL NEXT WEEK WITH EASTERN PACIFIC UPPER  
TROUGHS/IMPULSES THAT WORK DOWNSTREAM ACROSS THE U.S. NORTHERN  
TIER AND SOUTHERN CANADA. ROUGHLY TEN TO FIFTEEN DEGREE LONGITUDE  
WAVELENGTH SPACING BETWEEN ORGANIZED SYSTEMS SEEMS RIGHT AT THE  
CRITICAL POINT TO FORCE PROGRESSION. THIS ALONG WITH SMALLER SCALE  
SYSTEM DIFFERENCES THAT GROW OVER THE REST OF THE CONUS SEEMED TO  
OVERALL JUSTIFY EARLIER GUIDANCE PREFERENCE FOCUS DAYS 3-7  
(SUNDAY-NEXT THURSDAY) MAINLY ON THE MORE COMPATIBLE WELL BLENDED  
GEFS/ECMWF ENSEMBLE MEANS AND THE NATIONAL BLEND OF MODELS WHOSE  
SOLUTIONS TEND TO MITIGATE VARIANCE CONSISTENT WITH UNCERTAINTY.  
THIS ALSO ACTED TO MAINTAIN DECENT WPC PRODUCT CONTINUITY.  
HOWEVER, THE LATEST 00 UTC MODELS HAVE COME INTO MUCH BETTER  
AGREEMENT WITH NORTHERN STREAM SYSTEM TIMING AS THE GFS HAS SPED  
UP TO AND THE CANADIAN/UKMET SLOWED DOWN TOO SOLUTIONS NOW IN LINE  
WITH THE MORE CONSISTENT 12/00 UTC ECMWF RUNS, BOLSTERING FORECAST  
CONFIDENCE IN A SOLUTION ALSO PRETTY COMPATIBLE WITH THE  
AFOREMENTIONED ENSEMBLE MEANS.  
 
SCHICHTEL  
 
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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