736  
FXUS02 KWBC 020659  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
258 AM EDT MON MAY 02 2022  
 
VALID 12Z THU MAY 05 2022 - 12Z MON MAY 09 2022  
 
...SEVERE WEATHER AND ENHANCED RAINFALL THREAT WITH SOUTHERN  
STREAM CLOSED LOW TRACK THURSDAY INTO SATURDAY...  
...HEAVY SNOW THREAT FROM THE NORTHWEST TO THE NORTH-CENTRAL GREAT  
BASIN/ROCKIES FRIDAY-NEXT MONDAY...  
...ACTIVE PATTERN SET TO TRANSITION TO OMEGA-STYLE BLOCKY PATTERN  
BY EARLY NEXT WEEK...  
 
   
..MODEL GUIDANCE EVALUATION
 
 
GUIDANCE REMAINS VARIED WITH THE PROGRESSION OF A CLOSED UPPER LOW  
TRACKING OUT OF THE WEST INTO THE PLAINS AND EASTWARD, WITH THE  
GFS/GEFS MEAN STILL ON THE FAST SIDE COMPARED TO THE BETTER  
CLUSTERED AND SLOWER RECENT ECMWF/UKMET/CANADIAN AND ECMWF  
ENSEMBLE MEAN SOLUTIONS. THE WPC FORECAST CONTINUES TO LEAN  
TOWARDS THE SLOWER SIDE OF THE FORECAST ENVELOPE, GIVEN  
CONTINUITY, BUT ALSO THE GENERAL NATURE OF A SEPARATED SOUTHERN  
STREAM FLOW WITH AN EMBEDDED CLOSED SYSTEM. LATEST 12 UTC MODELS  
AND ENSEMBLES CONTINUE TO TREND IN THIS DIRECTION. THIS  
COMBINATION SEEMS TO WORK WELL FOR MUCH OF THE REST OF THE COUNTRY  
AND MAINTAINS GOOD WPC PRODUCT CONTINUITY, ALBEIT WITH MORE  
EMPHASIS ON THE ECMWF ENSEMBLE MEAN INTO DAY 6/7 AMID GROWING  
FORECAST SPREAD. OUT WEST, THERE REMAINS A GENERAL THEME OF  
LEADING MAIN UPPER TROUGHING TO REACHING THE COAST THURSDAY, WITH  
GUIDANCE CONVERGING ON DEPICTION OF A MORE DIGGING SYSTEM OVER THE  
WEEKEND INTO EARLY NEXT WEEK AS PART OF A DEVELOPING OMEGA STYLE  
BLOCK OVER THE LOWER 48 TO ALSO INCLUDE DOWNSTREAM DEVELOPMENT OF  
AN AMPLIFIED AND WARMING EAST-CENTRAL U.S. UPPER RIDGE AND STORMY  
WESTERN ATLANTIC CLOSED LOW/TROUGH.  
   
..PATTERN OVERVIEW AND WEATHER/THREAT HIGHLIGHTS
 
 
A CLOSED UPPER TROUGH AND WELL ORGANIZED SURFACE LOW/FRONTAL  
SYSTEM IS EXPECTED TO TRACK FROM THE SOUTH-CENTRAL PLAINS TO THE  
MISSISSPPI VALLEY/MIDWEST TO THE MID-ATLANTIC THURSDAY-SATURDAY.  
THE STORM PREDICTION CENTER SHOWS A THREAT FOR SEVERE WEATHER  
THURSDAY/FRIDAY FROM THE SOUTHERN PLAINS TO THE MID-SOUTH. STRONG  
STORMS ARE ALSO POSSIBLE INTO THE WEEKEND WITH SLOW/STEADY  
DOWNSTREAM TRACK OF THE SYSTEM. UPPER DIFFLUENCE, MOISTURE INFLOW  
AND INSTABILITY WILL ALSO OFFER A THREAT FOR ENHANCED COMMA HEAD  
AND WAVY LEAD/TRAILING FRONTAL RAINFALL FOCUS FROM THE MID-LOWER  
MISSISSIPPI AND OHIO VALLEYS TO THE APPALACHIANS/MID-ATLANTIC  
THURSDAY-SATURDAY.  
 
THE DIGGING OF A MODERATELY AMPLIFIED/DYNAMIC UPPER TROUGH AND  
FRONTAL SYSTEM ENERGIES ACROSS THE WEST COAST AND SUBSEQUENT  
INLAND PROGRESS THURSDAY THROUGH THE WEEKEND WILL BRING A  
WIDESPREAD PRECIPITATION FOCUS FROM THE NORTHWEST THROUGH THE  
NORTH-CENTRAL GREAT BASIN/ROCKIES AND HEIGHT FALLS/COOLING WILL  
FAVOR A THREAT FOR HEAVY TERRAIN FOCUSING SNOWS. UPPER  
DYNAMICS/FRONTAL TRANSLATION SHOULD ALSO SUPPORT AN EMERGING  
CONVECTION/RAINFALL PATTERN WITH LOCAL RUNOFF CONCERNS ACROSS THE  
NORTH-CENTRAL U.S. BY LATER WEEKEND/EARLY NEXT WEEK.  
 
UPSTREAM, THE GUIDANCE SIGNAL IS GROWING FOR YET ANOTHER FRONTAL  
SURGE INTO THE WEST FOR THER WEEKEND INTO EARLY NEXT WEEK AS  
UNSETTLING UPPER TROUGH ENERGIES SEEM SET TO DIG MORE EARNESTLY  
INTO THE REGION THAT MAY LEAD TO CLOSED LOW/TROUGH DEVELOPMENT  
OVER THE SOUTH-CENTRAL GREAT BASIN/SOUTHWEST AS PART OF A LARGE  
SCALE OMEGA STYLE BLOCK TO ALSO INCLUDE DOWNSTREAM DEVELOPMENT OF  
AN AMPLIFIED AND WARMING EAST-CENTRAL U.S. UPPER RIDGE AND STORMY  
WESTERN ATLANTIC CLOSED LOW/TROUGH.  
 
SCHICHTEL  
 
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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