790  
FXUS02 KWBC 220703  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
302 AM EDT WED JUN 22 2022  
 
VALID 12Z SAT JUN 25 2022 - 12Z WED JUN 29 2022  
 
...EXCESSIVE HEAT WILL CONTINUE ACROSS PARTS OF THE SOUTH ON  
SATURDAY, FINALLY BEGINNING TO MODERATE BY SUNDAY...  
 
   
..OVERVIEW
 
 
BROAD UPPER LEVEL RIDGING OVER THE SOUTHERN U.S. WILL FINALLY  
BEGIN TO WEAKEN AND BREAK DOWN THIS WEEKEND AS A SHORTWAVE THROUGH  
THE NORTHERN TIER TO THE NORTH BEGINS TO AMPLIFY AS IT REACHES THE  
GREAT LAKES AND ESPECIALLY THE NORTHEAST EARLY NEXT WEEK.  
MEANWHILE, MONSOONAL MOISTURE WILL CONTINUE TO PERSIST INTO THE  
FOUR CORNERS REGION THROUGH MUCH OF THE PERIOD WITH POTENTIAL FOR  
HEAVIER TO EXCESSIVE RAINS ALONG THE SOUTHERN HALF OF THE ROCKIES  
THIS WEEKEND WITH THE ARRIVAL OF A SURFACE FRONT AND TRAILING LOW  
LEVEL UPSLOPE FLOW. THE PATTERN LOOKS TO BECOME MORE AMPLIFIED BY  
EARLY NEXT WEEK ACROSS THE CONUS WITH TROUGHING IN THE EAST AND  
THE ARRIVAL OF A CLOSED UPPER LOW TOWARDS THE WEST COAST, AND  
RIDGING BUILDING IN BETWEEN OVER THE INTERIOR WEST.  
 
   
..GUIDANCE/PREDICTABILITY EVALUATION
 
 
THE LATEST GUIDANCE WAS IN FAIRLY GOOD AGREEMENT THE FIRST COUPLE  
OF DAYS BOTH WITH A WEAK/LINGERING CUTOFF LOW OFF THE NORTHEAST  
COAST (WHICH SHOULD GET PUSHED EASTWARD BY THE WESTERLIES) AND  
ALSO WITH THE COMPACT LOW/SHORTWAVE ALONG THE U.S./CANADIAN BORDER  
THIS WEEKEND. THE GFS GETS A LITTLE FAST WITH LEADING ENERGY AS IT  
MOVES INTO THE GREAT LAKES, BUT BIGGER UNCERTAINTIES ARISE LATE  
PERIOD WITH REINFORCING ENERGY DROPPING INTO THE TROUGH FROM  
CENTRAL CANADA WITH THE CMC BEING MUCH STRONGER WITH THIS ENERGY  
AND ACTUALLY ADVERTISING A CLOSED LOW NORTH OF LAKE SUPERIOR ON  
DAY 7. DETAIL/TIMING DIFFERENCES ALSO ARE IN QUESTION WITH THE  
LEADING ENERGY AS IT MOVES INTO THE NORTHEAST DAY 6-7 AS WELL.  
 
ELSEWHERE, THE GFS HAS CONSISTENTLY BEEN FASTER BRINGING A CLOSED  
LOW TOWARDS THE WEST COAST BY EARLY NEXT WEEK. THE REMAINDER OF  
THE DETERMINISTIC GUIDANCE IS SLOWER, WHICH IS ALSO MORE  
CONSISTENT WITH THE ENSEMBLE MEANS. THIS ALSO HAS IMPLICATIONS  
DOWNSTREAM FOR ARRIVAL OF THE RIDGE AND CONSEQUENTLY TEMPERATURES  
ACROSS THE NORTHERN HIGH PLAINS LATE PERIOD.  
 
THE EARLY PERIOD AGREEMENT ALLOWED FOR A GENERAL BLEND OF THE  
DETERMINISTIC GUIDANCE FOR DAYS 3-4, WEIGHTED MORE TOWARDS THE  
ECMWF WHICH SEEMED MOST CONSISTENT WITH THE ENSEMBLE MEANS.  
REMOVED THE GFS FROM THE BLEND AFTER DAY 4 DUE TO ITS ISSUES WITH  
THE WEST COAST UPPER LOW, AND THE CMC WITH IT'S ISSUES WITH  
RELOADING ENERGY INTO THE GREAT LAKES TROUGH. LATE PERIOD, RELIED  
HEAVILY ON THE ENSEMBLE MEANS TO HELP MITIGATE LATE PERIOD  
DIFFERENCES IN THE WEST, BUT DID CONTINUE INCORPORATION OF THE  
ECMWF FOR SOME ADDED SYSTEM DEFINITION.  
 
   
..SENSIBLE WEATHER/THREAT HIGHLIGHTS
 
 
ANOMALOUSLY HIGH MONSOONAL MOISTURE FOR THIS TIME OF YEAR, LIKELY  
TIED AT LEAST IN PART TO AN EASTERN PACIFIC TROPICAL SYSTEM, WILL  
CONTINUE STREAMING INTO THE FOUR CORNERS STATES INTO EARLY NEXT  
WEEK. LOCALLY HEAVY TO EXCESSIVE RAINFALL IS POSSIBLE,  
PARTICULARLY OVER SENSITIVE BURN SCAR AREAS AND CONSIDERING THE  
MULTIPLE DAY REPEATING NATURE OF THIS ACTIVITY. RAINFALL MAY TREND  
HEAVIER OVER PARTS OF COLORADO/NEW MEXICO BY THE WEEKEND AS A  
FRONT DROPPING SOUTH THROUGH THE REGION AND TRAILING LOW LEVEL  
UPSLOPE FLOW COULD INTERACT WITH THE MOISTURE ALREADY IN PLACE.  
MODELS SHOWED ENOUGH AGREEMENT FOR THE INCLUSION OF A SLIGHT RISK  
IN NORTHEAST NEW MEXICO ON THE EXPERIMENTAL DAY 5 ERO. MOISTURE  
WILL CONTINUE ROUNDING THE TOP OF THE RIDGE THROUGH THE PLAINS,  
WHILE INTERACTING WITH A COLD FRONT THROUGH THE UPPER MIDWEST,  
WHERE SOME INCREASED THREAT FOR ORGANIZED SHOWERS IS POSSIBLE. THE  
COLD FRONT SHOULD BE FAIRLY PROGRESSIVE THROUGH THE MIDWEST AND  
INTO THE EAST THIS WEEKEND, BUT WITH ENOUGH MOISTURE AND  
INSTABILITY ALONG THE BOUNDARY PRESENT, SOME LOCALLY HIGHER TOTALS  
SEEM LIKELY, SPECIFIC AMOUNTS AND LOCATIONS THO REMAIN HIGHLY  
DEPENDENT ON STILL UNCERTAIN TIMING OF THE FRONT. A FRONT SETTLING  
ACROSS THE SOUTHEAST INTO SATURDAY SHOULD ALSO BRING A PERIOD OF  
ENHANCED RAINFALL TO PARTS OF THE FLORIDA PENINSULA.  
 
EXCESSIVE HEAT ACROSS THE SOUTHERN U.S. SHOULD FINALLY BEGIN TO  
WANE SOME, ESPECIALLY IN PARTS OF THE SOUTHEAST, BY THIS WEEKEND.  
ANOMALIES AVERAGING 10 TO 15 DEGREES ABOVE NORMAL WILL CONTINUE  
ACROSS THE LOWER MISSISSIPPI VALLEY AND SOUTHERN PLAINS WITH  
ANOTHER FEW DAYS OF RECORDS BOTH FOR DAYTIME HIGHS AND WARM  
OVERNIGHT MINS. BY EARLY NEXT WEEK, TEMPERATURES ALL ACROSS THE  
SOUTH SHOULD FINALLY TREND BACK TOWARDS NORMAL. RELATIVELY COOLER  
TEMPERATURES WITH WELL BELOW NORMAL HIGHS ARE LIKELY TO BE MOST  
PERSISTENT OVER PARTS OF NEW MEXICO AND COLORADO GIVEN THE  
MONSOONAL CLOUDS AND RAIN COVERAGE. THE NORTHERN HIGH PLAINS MAY  
ALSO SEE COOL HIGHS FROM SATURDAY INTO SUNDAY. THE WEST COAST  
STATES SHOULD SEE HIGHS 5-15F ABOVE AVERAGE THROUGH ABOUT TUESDAY  
AS UPPER RIDGING MOVES THROUGH THE REGION.  
 
SANTORELLI  
 
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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