309  
FXUS02 KWBC 130700  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 AM EDT MON JUN 13 2022  
 
VALID 12Z THU JUN 16 2022 - 12Z MON JUN 20 2022  
 
...EAST-CENTRAL/SOUTHEASTERN U.S. HEAT TO BEGIN MODERATING AFTER  
MIDWEEK...  
 
...HEAT LIKELY TO BECOME ESTABLISHED OVER THE NORTHERN-CENTRAL  
PLAINS FRIDAY THROUGH AT LEAST THE WEEKEND...  
 
   
..OVERVIEW AND GUIDANCE/PREDICTABILITY EVALUATION
 
 
LATEST GUIDANCE CONTINUES TO SHOW SIGNIFICANT AMPLIFICATION OF THE  
UPPER PATTERN FROM LATE WEEK INTO THE WEEKEND, WITH A TROUGH AND  
EMBEDDED CLOSED LOW NEARING THE WEST COAST AND A STRONG RIDGE OVER  
THE CENTRAL U.S. MEANWHILE A TROUGH WILL PROGRESS ACROSS THE  
NORTHEASTERN QUADRANT OF THE LOWER 48. THEN AFTER EARLY SATURDAY  
THE WEST COAST TROUGH SHOULD DRIFT A LITTLE INLAND AND WEAKEN  
SOMEWHAT, DEPENDING ON EXACTLY HOW ENERGY MAY EJECT FROM THE  
FEATURE, WHILE THE STRENGTH OF THE CENTRAL U.S. RIDGE SHOULD FAVOR  
FURTHER AMPLIFICATION/PERSISTENCE OF UPPER TROUGHING ALONG OR JUST  
OFFSHORE THE EAST COAST. THIS PATTERN SHOULD PROMOTE THE HIGHEST  
TEMPERATURE ANOMALIES OVER THE NORTHERN-CENTRAL PLAINS FROM LATE  
WEEK THROUGH THE WEEKEND, WITH A FRONTAL SYSTEM POTENTIALLY  
STARTING TO ERODE THIS AREA OF HEAT FROM THE WEST BY NEXT MONDAY.  
NOTABLE AREAS OF PRECIPITATION DURING THE PERIOD WILL LIKELY BE  
WITH A FRONT CROSSING THE EAST LATE THIS WEEK INTO THE WEEKEND,  
DIURNALLY FAVORED CONVECTION OVER THE GULF COAST AND FLORIDA,  
ACROSS PARTS OF THE FOUR CORNERS STATES WITH A NORTHWARD SURGE OF  
MOISTURE, AND OVER PORTIONS OF THE NORTHWESTERN U.S. PLUS  
EVENTUALLY THE NORTHERN PLAINS WITH THE WEST COAST TROUGH AND  
ASSOCIATED SURFACE WAVES/FRONTS.  
 
OVER RECENT RUNS ONE OF THE MOST CONTENTIOUS PARTS OF THE FORECAST  
HAS BEEN WITH UPPER FLOW OVER THE NORTHEAST DURING THE WEEKEND,  
WITH SOME GFS RUNS SO STRONG AND EASTWARD/NORTHEASTWARD WITH THE  
CENTRAL U.S. RIDGE THAT RIDGING WOULD EXTEND INTO THE NORTHEAST IN  
CONTRAST TO AMPLIFIED/WESTWARD TROUGHING IN ECMWF RUNS THAT WOULD  
HAVE AN UPPER LOW NEAR THE COAST OF NEW ENGLAND OR EVEN THE  
NORTHERN MID-ATLANTIC. THE FULL ARRAY OF OTHER MODELS/ENSEMBLE  
MEANS ALONG WITH TELECONNECTIONS RELATIVE TO CONSENSUS IDEAS FOR  
THE CENTRAL U.S. RIDGE AND ANOTHER RIDGE OVER THE  
EAST-CENTRAL/NORTHERN ATLANTIC OCEAN HAVE BEEN FAVORING A MEAN  
TROUGH NEAR OR JUST OFFSHORE THE EAST COAST BUT WITH SOME MIXED  
SIGNALS FOR EXACT AMPLITUDE. THE 18Z GFS IMPROVED UPON THE 12Z  
RUN AND NOW THE 00Z GFS HAS ADJUSTED VERY CLOSE TO THE ECMWF  
SCENARIO BY SATURDAY, FOLLOWED BY AN EVOLUTION CLOSER TO THE  
ENSEMBLE MEANS VERSUS THE 12Z ECMWF THAT KEPT THE CORE OF THE  
TROUGH FARTHER SOUTH.  
 
FOR THE UPPER TROUGH REACHING THE WEST COAST AND THEN DRIFTING  
INLAND, THE ENSEMBLE MEANS HAVE BEEN QUITE CONSISTENT OVERALL IN  
RECENT DAYS. OPERATIONAL MODELS HAVE TENDED TO AGREE WELL FOR THE  
EMBEDDED UPPER LOW OUT TO ABOUT FOUR DAYS BEFORE GOING ASTRAY WITH  
RESPECT TO HOW ENERGY MAY BECOME DISTRIBUTED WITHIN THE TROUGH AND  
POTENTIALLY EJECT NORTHEASTWARD. BY DAY 7 MONDAY THE 12Z ECMWF  
AND 12Z/18Z GFS BROUGHT THE STRONGEST ENERGY INTO WEST-CENTRAL  
CANADA WHILE THE LATEST CMC RUNS HAVE BEEN OVER THE INTERIOR WEST.  
THE CORRESPONDING SURFACE REFLECTION IN THE MEANS IS CLOSER TO  
BUT A BIT SLOWER THAN THOSE ECMWF/GFS RUNS. THE NEW 00Z GFS/ECMWF  
HAVE MADE CONSIDERABLE DETAIL CHANGES, HIGHLIGHTING THE CONTINUED  
UNCERTAINTY WITH SPECIFICS LATER IN THE PERIOD.  
 
BASED ON THE ABOVE CONSIDERATIONS, THE UPDATED FORECAST STARTED  
WITH A 12Z/18Z OPERATIONAL MODEL COMPOSITE FOR THE FIRST HALF OF  
THE PERIOD AND THEN STEADILY INCORPORATED INCREASING 18Z GEFS/12Z  
ECMWF MEAN INPUT SO THAT THE MODELS/MEANS EACH HAD HALF WEIGHT BY  
DAY 7. THIS SOLUTION PROVIDED FAIRLY GOOD CONTINUITY, BY THE  
LATTER HALF OF THE PERIOD ACCOUNTING FOR ENSEMBLE MEAN  
CONSISTENCY/DETAIL UNCERTAINTY FOR THE WESTERN TROUGH WHILE  
DEPICTING AN INTERMEDIATE APPROACH FOR THE UPPER TROUGH NEAR THE  
EAST COAST.  
 
   
..SENSIBLE WEATHER/THREAT HIGHLIGHTS
 
 
THE COLD FRONT PROGRESSING EASTWARD FROM THE GREAT LAKES AND  
CENTRAL PLAINS WILL PRODUCE AREAS OF SHOWERS AND THUNDERSTORMS  
OVER THE EAST DURING THE LATTER HALF OF THE WEEK. SOME LOCALLY  
MODERATE TO HEAVY ACTIVITY WILL BE POSSIBLE. BEST POTENTIAL  
CURRENTLY APPEARS TO BE OVER AND NEAR THE APPALACHIANS BUT OTHER  
LOCATIONS COULD SEE ENHANCED TOTALS AS WELL. WHILE MOST AREAS  
SHOULD SEE A DRIER TREND AFTER FRONTAL PASSAGE, INCREASING  
POTENTIAL FOR UPPER TROUGHING/POSSIBLE CLOSED LOW OVER OR NEAR THE  
NORTHEAST MAY LEAD TO MULTIPLE DAYS OF SHOWERY WEATHER OVER THAT  
REGION. THE SOUTHEAST AND GULF COAST REGIONS MAY SEE DIURNALLY  
FAVORED SHOWERS AND THUNDERSTORMS ON ONE OR MORE DAYS, WITH SOME  
POTENTIAL FOCUS ALONG THE FRONT AS IT REACHES THE SOUTHEAST BY THE  
WEEKEND. CONVECTION OVER FLORIDA MAY BECOME SOMEWHAT HEAVIER  
DURING THE WEEKEND RELATIVE TO LATE THIS WEEK. THE UPPER TROUGH  
NEARING THE WEST COAST TOWARD THE END OF THE WEEK SHOULD INITIALLY  
BRING MAINLY LIGHT RAINFALL TO PARTS OF THE NORTHWEST, WITH AN  
INCREASE IN AMOUNTS AT LEAST ON A LOCALIZED BASIS POSSIBLE FARTHER  
INLAND DURING THE WEEKEND. SOME OF THIS ACTIVITY COULD REACH THE  
NORTHERN PLAINS BY EARLY NEXT WEEK. THE DEEP-LAYER FLOW BETWEEN  
THE WEST COAST TROUGH AND CENTRAL U.S. RIDGE WILL LIKELY BRING  
MUCH ABOVE NORMAL AMOUNTS OF MOISTURE FOR THE TIME OF YEAR  
NORTHWARD THROUGH THE FOUR CORNERS STATES AND VICINITY FRIDAY  
THROUGH THE WEEKEND, SUPPORTING AN INCREASE IN COVERAGE AND  
INTENSITY OF RAINFALL ACROSS THE REGION. RAIN/THUNDERSTORMS COULD  
CONTINUE OVER THIS REGION INTO EARLY NEXT WEEK AND THE MOISTURE  
MAY INTERACT WITH THE FRONT SLOWLY ADVANCING THROUGH THE WEST.  
 
THE EAST-CENTRAL U.S. HEAT WAVE SHOULD PERSIST INTO THURSDAY TO  
SOME EXTENT, WITH HIGHS UP TO 10-15F ABOVE NORMAL. A FEW  
LOCATIONS MAY SEE RECORD HIGHS AFTER VERY WARM MORNING LOWS, BUT  
OVERALL EXPECT THURSDAY TO BE LESS EXTREME THAN PRIOR DAYS. THEN  
THE EASTERN U.S. WILL SEE A PRONOUNCED COOLING TREND, INCLUDING  
BELOW NORMAL HIGHS OVER THE EASTERN GREAT LAKES/NORTHEAST DURING  
THE WEEKEND INTO EARLY NEXT WEEK. MEANWHILE THE HEAT FOCUS WILL  
SHIFT WESTWARD, WITH THE GREAT BASIN SEEING A COUPLE VERY WARM TO  
HOT DAYS LATE THIS WEEK AND THE NORTHERN-CENTRAL PLAINS LIKELY TO  
EXPERIENCE HIGHS OF 15-25F ABOVE NORMAL FRIDAY-SUNDAY, WITH THE  
AXIS OF HIGHEST ANOMALIES DRIFTING A BIT EASTWARD WITH TIME.  
SCATTERED RECORD HIGHS WILL BE POSSIBLE. BY MONDAY A COLD FRONT  
MAY BRING COOLER AIR TO THE HIGH PLAINS AND PUSH PLUS 10-20F  
ANOMALIES A LITTLE FARTHER EAST. SOUTHERN PORTIONS OF THE PLAINS  
SHOULD STAY ON THE HOT SIDE WITH HIGHS 5-10F ABOVE NORMAL THROUGH  
THE PERIOD. MODERATELY BELOW NORMAL HIGHS WILL SPREAD EASTWARD  
ACROSS THE WEST FRIDAY-SUNDAY AND THEN TREND CLOSER TO NORMAL BY  
MONDAY.  
 
RAUSCH  
 
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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