303  
FXUS02 KWBC 170701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 AM EDT FRI JUN 17 2022  
 
VALID 12Z MON JUN 20 2022 - 12Z FRI JUN 24 2022  
 
...EXPANSIVE AREA OF HEAT TO SHIFT FROM THE NORTHERN  
PLAINS/MIDWEST INTO THE SOUTH NEXT WEEK...  
 
   
..OVERVIEW AND GUIDANCE/PREDICTABILITY EVALUATION
 
 
THE LATEST GUIDANCE STAYS CONSISTENT IN SHOWING A TRANSITION FROM  
AN AMPLIFIED TROUGH-RIDGE-TROUGH PATTERN ON MONDAY TOWARDS A MORE  
TYPICAL SUMMER-LIKE PATTERN THROUGH THE REST OF NEXT WEEK. THIS  
FEATURES STRONG UPPER RIDGING EXPANDING ACROSS THE SOUTH AS WEAKER  
AND MORE PROGRESSIVE SYSTEMS RIDE OVER TOP THROUGH THE NORTHERN  
TIER STATES. THE MODELS SHOW GOOD ENOUGH AGREEMENT FOR A GENERAL  
DETERMINISTIC MODEL BLEND THE FIRST HALF OF NEXT WEEK AS A CLOSED  
LOW EXITS THE NORTHEAST AND A SHORTWAVE LIFTS THROUGH THE NORTHERN  
PLAINS. AFTER WEDNESDAY, UNCERTAINTIES BEGIN TO ARISE WITH RESPECT  
TO TIMING AND DETAILS OF FLOW OFF THE EAST COAST AND IN THE WEST.  
THE GFS SEEMS AN OUTLIER ON BOTH ENDS AS IT IS STRONGEST AND  
FARTHEST SOUTH TO CUT OFF A LINGERING UPPER LOW OFF THE NORTHEAST  
COAST, AND ALSO SLOWEST/FARTHER NORTH WITH A POSSIBLE CLOSED LOW  
NEAR THE NORTHWEST U.S. NEXT THURSDAY-FRIDAY. THE CMC SEEMS MUCH  
TO QUICK WITH THE TROUGH OFF THE NORTHEAST COAST INTO THE CANADIAN  
MARITIMES, COMPARED TO THE ENSEMBLE MEANS, SO IT WAS EXCLUDED FROM  
THE BLEND BEYOND WEDNESDAY. OUT WEST, THE ECMWF IS THE CLOSEST  
PROXY TO THE ENSEMBLE MEANS SHOWING A CLOSED LOW OVER SOUTHERN  
BRITISH COLUMBIA (THE GFS KEEPS THIS SYSTEM STILL OFFSHORE). A  
MAJORITY BLEND OF THE ENSEMBLE MEANS (WITH SOME MODEST WEIGHTING  
OF THE DETERMINISTIC ECMWF) WAS USED FOR DAYS 6-7 TO HELP MITIGATE  
THESE DIFFERENCES.  
 
   
..SENSIBLE WEATHER/THREAT HIGHLIGHTS
 
 
THE BIGGEST WEATHER HAZARD DURING THE MEDIUM RANGE PERIOD WILL BE  
A DOME OF HEAT AND ANOMALOUS WARMTH EXPANDING FROM THE UPPER  
MIDWEST ON MONDAY INTO THE SOUTHERN STATES BY WEDNESDAY-FRIDAY.  
THE GREATEST ANOMALIES ARE EXPECTED FROM PARTS OF THE CENTRAL  
PLAINS TO THE UPPER MIDWEST WITH DAYTIME HIGHS AS MUCH AS 20 TO 25  
DEGREES ABOVE NORMAL. THIS EQUATES TO HIGH TEMPERATURES IN THE MID  
TO UPPER 90S AND LOW 100S WITH OVERNIGHT LOWS IN THE MID TO UPPER  
70S STRUGGLING TO PROVIDE MUCH RELIEF. RECORD HIGH MAX AND MIN  
TEMPERATURES ARE LIKELY IN MANY PLACES. BY TUESDAY TO FRIDAY, THE  
HEAT SUPPRESSES SOUTH WITH THE UPPER RIDGE INTO THE MIDWEST AND  
EVENTUALLY THE SOUTH WITH SEVERAL DAYS OF HIGH TEMPERATURES NEAR  
OR EXCEEDING 100F FROM CENTRAL TEXAS TO THE SOUTHEAST AND  
WIDESPREAD HIGH TEMPERATURE RECORDS LIKELY TO BE CHALLENGED.  
 
TO THE NORTH, SYSTEMS MOVING THROUGH THE NORTHERN TIER WILL FOCUS  
SOME AREAS OF LOCALLY MODERATE TO HEAVY PRECIPITATION, WITH THE  
BEST POTENTIAL OVER/NEAR THE NORTHERN ROCKIES AND PLAINS ON  
MONDAY. HIGHEST ELEVATIONS MAY SEE SOME LIGHT SNOW AS WELL WITH  
THIS SYSTEM. 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. 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 CONSENSUS SHOWS 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. THE FLORIDA PENINSULA SHOULD SEE  
MULTIPLE DAYS OF DIURNAL SHOWERS/STORMS FROM THE WEEKEND INTO NEXT  
WEEK AS A FRONT PUSHING INTO AREA DECELERATES AND EVENTUALLY  
DISSIPATES.  
 
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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