485  
FXUS02 KWBC 280701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 AM EDT MON MAR 28 2022  
 
VALID 12Z THU MAR 31 2022 - 12Z MON APR 04 2022  
 
...A DEEP AND WINDY STORM TO BRING A LATE WEEK THREAT OF UPPER  
GREAT LAKES HEAVY SNOW AND HEAVY RAIN/SEVERE WEATHER TO THE EAST...  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A  
COMPOSITE OF BEST CLUSTERED GUIDANCE FROM THE 18 UTC GFS AND 12  
UTC ECMWF/CANADIAN ALONG WITH THE 01 UTC NATIONAL BLEND OF MODELS  
DAYS 3/4 (THURSDAY-FRIDAY) IN A STORMY PATTERN WITH ABOVE NORMAL  
PREDICTABILITY. THIS BLEND IS ALSO WELL SUPPORTED BY ENSEMBLES AND  
00 UTC MODEL GUIDANCE.  
 
EMBEDDED SMALLER SCALE SYSTEM DIFFERENCES IN THE MAIN TWO FLOW  
STREAMS AND RUN TO RUN CONTINUITY VARIANCE BECOMES MORE  
PROBLEMATIC FROM THE WEEKEND ONWARD DESPITE REASONABLY SIMILAR  
LARGER SCALE PATTERN EVOLUTIONS. A BLEND OF MORE COMPATIBLE  
GUIDANCE FROM THE 18 UTC GEFS MEAN AND 12 UTC ECMWF ENSEMBLE MEAN  
TENDS TO MITIGATE THE LESS PREDICTABLE FORECAST COMPONENTS WHILE  
INCLUSION OF THE MOST COMPATIBLE MODEL, THE 12 UTC ECMWF, PROVIDES  
A BIT MORE DETAIL CONSISTENT WITH A PATTERN WITH NEAR AVERAGE  
PREDICTABILITY. OVERALL, WPC PRODUCT CONTINUITY IS WELL MAINTAINED  
WITH THIS STRATEGY AND THE FORECAST SEEMS IN LINE WITH A COMPOSITE  
OF 00 UTC GUIDANCE.  
 
   
..OVERVIEW AND WEATHER HIGHLIGHTS/THREATS
 
 
A DEEP AND WINDY STORM SET TO LIFT FROM THE GREAT LAKES TO EASTERN  
CANADA THURSDAY INTO FRIDAY OFFERS A THREAT FOR WRAPPING HEAVY  
SNOWS NORTH OF THE LOW TRACK. HEAVY RAINFALL WILL SWEEP ACROSS THE  
EASTERN SEABOARD WITH FRONTAL SYSTEM PROGRESSION THURSDAY ALONG  
WITH A SEVERE WEATHER THREAT FOCUS OVER THE MID-ATLANTIC AS PER  
SPC.  
 
A PROTRACTED SERIES OF MORE MODEST UPSTREAM UPPER TROUGH ENERGIES  
AND FRONTAL SYSTEMS FORECAST TO DIG WITH SOME UNCERTAINTY THROUGH  
THE WEST LATER WEEK INTO NEXT WEEK COULD EACH PROVIDE AN  
OPPORTUNITY FOR ENHANCED ROUNDS OF WINTRY WEATHER, MAINLY FOR THE  
NORTH-CENTRAL INTERMOUNTAIN WEST/ROCKIES. POTENTIAL SYSTEM  
AMPLITUDE AND PROGRESSION INTO NEXT WEEKEND/EARLY NEXT WEEK WOULD  
FAVOR RETURN MOISTURE INTO A WAVY FRONTAL PATTERN. THIS MAY  
SUPPORT A HEAVY RAINFALL FOCUS FROM THE GULF COAST STATES TO THE  
SOUTHEAST/MID-ATLANTIC. BY EARLY NEXT WEEK THERE IS ALSO A  
GUIDANCE SIGNAL TO BRING MORE ENERGETIC PACIFIC FLOW TOWARD THE  
WEST COAST IN TWO STREAMS TO BE MONITORED.  
 
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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