301  
FXUS02 KWBC 180701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 AM EDT SAT JUN 18 2022  
 
VALID 12Z TUE JUN 21 2022 - 12Z SAT JUN 25 2022  
 
...EXPANSIVE AREA OF HEAT TO SHIFT FROM THE MIDWEST INTO THE SOUTH  
NEXT WEEK...  
 
   
..OVERVIEW AND GUIDANCE/PREDICTABILITY EVALUATION
 
 
THE OVERALL PATTERN DURING THE MEDIUM RANGE PERIOD FEATURES A  
PERSISTANT AND VERY WARM UPPER LEVEL RIDGE EXPANDING ACROSS THE  
SOUTHERN U.S. AS WEAK AND PROGRESSIVE SYSTEMS RIDE OVERTOP THROUGH  
THE NORTHERN TIER. THE GUIDANCE CONSTINUES TO SHOW REASONABLY GOOD  
AGREEMENT ON THE LARGE SCALE PATTERN THROUGH THE PERIOD, THOUGH  
WITH SOME LINGERING DIFFERENCES IN THE DETAILS AND TIMING OF  
INDIVIDUAL SYSTEMS. RECENT RUNS OF THE DETERMINISTIC MODELS HAVE  
TRENDED FASTER WITH AN AMPLIFIED TROUGH OFF THE NORTHEAST EARLY  
NEXT WEEK, WHICH WOULD ALLOW FOR MORE RIDGE BUILDING AND WARMTH  
ACROSS THE MID-ATLANTIC STATES. BUT THE ENSEMBLE MEANS ARE STILL  
SLOWER SUGGESTING A FAIR BIT OF UNCERTAINTY STILL WITH REGARDS TO  
TEMPERATURES ACROSS THE REGION NEXT WEEK. ELSEWHERE, THE MOST  
NOTABLE DIFFERENCE IS THE CMC SEEMS TO BREAK DOWN THE WESTERN EDGE  
OF THE RIDGE TOO FAST ALLOWING FOR A MORE AMPLIFIED AND FASTER  
SHORTWAVE INTO THE NORTHWEST AND MOVING INTO THE NORTHERN PLAINS  
LATE NEXT WEEK. MEANWHILE, THE ECMWF AND GFS HAVE CONSISTENTLY  
SUGGESTED A FARTHER WESTWARD EXPANSION OF THE SOUTHERN RIDGE AND  
THUS THE SHORTWAVE AXIS TENDS TO LINGER MORE OVER THE  
NORTHWEST/WESTERN CANADA INTO NEXT WEEKEND, WHICH HAS MORE SUPPORT  
FROM THE ENSEMBLE MEANS. THE WPC BLEND FOR TONIGHT FAVORED THE  
DETERMINISTIC MODELS EARLY ON, AND INCREASING THE ENSEMBLE MEANS  
LATE PERIOD (IN PLACE OF THE CMC).  
 
   
..SENSIBLE WEATHER/THREAT HIGHLIGHTS
 
 
THE BIGGEST WEATHER HAZARD DURING THE MEDIUM RANGE PERIOD WILL BE  
A DOME OF HEAT AND ANOMALOUS WARMTH ACROSS MUCH OF THE EASTERN  
HALF OF THE COUNTRY NEXT WEEK. THE GREATEST ANOMALIES (GENERALLY  
10-15+ ABOVE NORMAL) WILL SHIFT FROM THE MIDWEST ON TUESDAY INTO  
THE SOUTH WEDNESDAY-FRIDAY, MEANING HIGH TEMPERATURES IN THE MID  
TO UPPER 90S AND LOW 100S LIKELY AND LITTLE RELIEF OVERNIGHT AS  
LOW TEMPERATURES HOVER IN THE MID TO UPPER 70S. WIDESPREAD RECORD  
HIGH MAX AND MIN TEMPERATURES ARE LIKELY IN MANY PLACES.  
 
NORTHWARD STREAMING ANOMALOUS MOISTURE WEST OF THE RIDGE WILL  
BRING AN UNUSUALLY EARLY MONSOON TYPE PATTERN TO PARTS OF THE FOUR  
CORNERS STATES AND VICINITY, MAINLY EARLY IN THE WEEK, SUPPORTING  
AN INCREASE IN COVERAGE AND INTENSITY OF RAINFALL ACROSS THE  
REGION WITH AT LEAST LOCAL FLOOD AND FLASH FLOOD THREATS. BY MID  
WEEK, THERE ARE STILL MIXED SIGNALS OVER HOW MUCH RAINFALL THE  
INTERACTION OF THIS MOISTURE WITH THE WESTERN FRONT ADVANCING INTO  
THE PLAINS WILL PRODUCE. HOWEVER, THE POTENTIAL FOR SOME  
TRAINING/REPEAT ACTIVITY MAY HAVE TO BE MONITORED AS MODELS  
CONTINUE TO SHOW THIS PLAINS FRONT BECOMING ALIGNED WEST-EAST  
ALONG THE SOUTHERN EDGE OF THE WESTERLIES BY WEDNESDAY-THURSDAY.  
FARTHER EAST, AN AREA OF SHOWERS AND THUNDERSTORMS MAY PUSH ACROSS  
THE GREAT LAKES AND POSSIBLY INTO THE NORTHEAST AHEAD OF AN  
ADVANCING WARM FRONT, WITH SOME ACTIVITY POSSIBLY ON THE HEAVY  
SIDE EARLIER IN THE PERIOD.  
 
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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