920  
FXUS02 KWBC 260658  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
256 AM EDT THU MAY 26 2022  
 
VALID 12Z SUN MAY 29 2022 - 12Z THU JUN 2 2022  
   
..WEATHER PATTERN OVERVIEW
 
 
A MORE AMPLIFIED UPPER LEVEL PATTERN IS EXPECTED TO BECOME  
ESTABLISHED OVER THE CONTINENTAL U.S. GOING INTO THE MEMORIAL DAY  
WEEKEND AND EXTENDING INTO THE MIDDLE OF NEXT WEEK. MULTIPLE  
SHORTWAVE IMPULSES WILL REINFORCE A RATHER DEEP SYNOPTIC SCALE  
TROUGH OVER THE WESTERN U.S. WHILST A LARGE UPPER RIDGE AND CLOSED  
HIGH BUILDS DOWNSTREAM ACROSS THE MISSISSIPPI RIVER VALLEY AND  
EVENTUALLY THE EASTERN U.S. BY EARLY NEXT WEEK. THIS OVERALL  
PATTERN WILL LIKELY BECOME MORE QUASI-ZONAL BY NEXT THURSDAY WITH  
THE WESTERN TROUGH LIFTING OUT AND THE RIDGE BREAKING DOWN SOME.  
   
..MODEL GUIDANCE AND PREFERENCES
 
 
THE 00Z MODEL GUIDANCE SUITE IS IN GOOD OVERALL AGREEMENT ON MOST  
ASPECTS OF THE FORECAST GOING THROUGH MEMORIAL DAY, AND MODEL  
SPREAD HAS DECREASED OVER THE PAST 24 HOURS WITH IMPROVED FORECAST  
CONFIDENCE. HOWEVER, MESOSCALE DIFFERENCES REGARDING SMALLER  
SCALE FEATURES REMAIN, AND THIS HAS AN EFFECT ON THE PLACEMENT OF  
MCS ACTIVITY AND HEAVIER AREAS OF RAINFALL. THERE IS ALSO  
INCREASING MODEL SPREAD REGARDING THE WEAKENING OF THE UPPER  
TROUGH BY LATE IN THE FORECAST PERIOD. HOWEVER, THERE IS VERY  
GOOD MODEL AGREEMENT ON THE BUILDING UPPER RIDGE OVER THE OHIO  
VALLEY GOING THROUGH THE MIDDLE OF NEXT WEEK. THE WPC FORECAST  
INCORPORATED SOME OF THE GEFS/ECENS MEANS FOR THE TUESDAY THROUGH  
THURSDAY TIME PERIOD TO ACCOUNT FOR THE MESOSCALE UNCERTAINTY,  
WHILST STILL MAINTAINING SOME OF THE DETERMINISTIC CMC/ECMWF/GFS,  
AND GENERALLY SHOWS GOOD CONTINUITY WITH THE PREVIOUS WPC FORECAST  
AS WELL.  
   
..SENSIBLE WEATHER/THREAT HIGHLIGHTS
 
 
THE MAIN FOCUS FOR PRECIPITATION WILL EXTEND FROM THE NORTHWESTERN  
U.S. THROUGH THE NORTHERN-CENTRAL PLAINS TO THE WESTERN GREAT  
LAKES. SHOWERS AND STORMS WILL INITIALLY DEVELOP ACROSS THE  
NORTHERN PLAINS AND UPPER MIDWEST IN RESPONSE TO A DEVELOPING LOW  
PRESSURE AND FRONTAL BOUNDARY OVER THE NORTH-CENTRAL U.S. ON  
SUNDAY, WHILE SOME PRECIPITATION EXTENDS BACK INTO THE NORTHERN  
ROCKIES AND VICINITY. ANOTHER STRONGER SHORTWAVE IS FORECAST TO  
SLOWLY CROSS THE ROCKIES AND INTERACT WITH THE WAVY AND SLOW  
MOVING FRONTAL SYSTEM SETTING UP OVER THE PLAINS. THE RESULT WILL  
BE LATE SEASON SNOW FOR THE HIGHER TERRAIN OF THE NORTHERN  
ROCKIES, WITH POTENTIALLY OVER A FOOT OF ACCUMULATION ABOVE 8000  
FEET ELEVATION. THERE IS ALSO AN INCREASING POTENTIAL FOR HEAVY  
RAINFALL ACROSS MUCH OF MONTANA, NORTHERN WYOMING, AND THE WESTERN  
DAKOTAS BY EARLY NEXT WEEK BEHIND THE FRONT WITH MOIST UPSLOPE  
FLOW, WITH PERHAPS 2 TO 4 INCHES FOR THE FOOTHILLS OF THE MONTANA  
ROCKIES. THE FOCUS FOR HEAVY RAINFALL AND STRONG STORMS IS THEN  
EXPECTED TO BE ACROSS THE CENTRAL PLAINS BY THE MIDDLE OF THE WEEK.  
 
TEMPERATURES WILL BE QUITE WARM ACROSS THE CENTRAL AND SOUTHERN  
PLAINS FOR THE WEEKEND WITH HIGHS REACHING WELL INTO THE 90S FROM  
SOUTHERN NEBRASKA TO THE GULF COAST, AND SOME LOW-MID 100S ACROSS  
WESTERN TEXAS WHICH COULD CHALLENGE SOME DAILY RECORDS. THE HEAT  
THEN BUILDS EASTWARD TO INCLUDE THE OHIO VALLEY AND EVENTUALLY THE  
EAST COAST GOING INTO EARLY NEXT WEEK, COMPLIMENTS OF THE BUILDING  
UPPER RIDGE AND SOUTHERLY FLOW AHEAD OF THE STORM SYSTEM OVER THE  
PLAINS. THIS WILL EQUATE TO WIDESPREAD UPPER 80S TO MIDDLE 90S  
FOR HIGHS GOING INTO THE BEGINNING OF JUNE. WELL BELOW NORMAL  
TEMPERATURES WILL LIKELY ENCOMPASS AREAS FROM THE PACIFIC  
NORTHWEST TO THE NORTHERN ROCKIES AND NORTHERN PLAINS AS THE UPPER  
TROUGH MOVES IN BEHIND THE COLD FRONT, WITH HIGHS 15 TO 25 DEGREES  
BELOW LATE MAY AVERAGES.  
 
HAMRICK  
 
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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