954  
FXUS02 KWBC 281917  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
317 PM EDT MON MAR 28 2022  
 
VALID 12Z THU MAR 31 2022 - 12Z MON APR 04 2022  
 
...A DEEP CYCLONE WILL LIKELY MOVE ACROSS THE GREAT LAKES WITH  
HIGH WINDS, GRADUALLY DEPARTING WRAP-AROUND SNOWS, AREAS OF HEAVY  
RAIN AND POSSIBLY SEVERE WEATHER ALONG THE EAST COAST ON  
THURSDAY...  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
LATEST MODEL GUIDANCE THIS MORNING CONTINUES WITH THE RECENT TREND  
OF LIFTING A DEEP CYCLONE FASTER ACROSS THE GREAT LAKES AS THE  
MEDIUM-RANGE PERIOD STARTS ON THURSDAY MORNING. THIS NORTHWARD  
TREND NOT ONLY RESULTED IN A FASTER PASSAGE OF THE CYCLONE CENTER  
ACROSS THE GREAT LAKES BUT ALSO LIFTED THE HEAVY RAINFALL AXIS IN  
THE WARM SECTOR FARTHER NORTH FROM NORTHERN FLORIDA INTO THE  
COASTAL PLAINS OF THE SOUTHEAST. THERE IS ALSO A CONTINUED MODEL  
TENDENCY TO PUSH THE COLD FRONT SLIGHTLY FASTER OFF THE EAST COAST  
ON FRIDAY.  
 
BEHIND THE DEPARTING CYCLONE, THE NEXT UPPER TROUGH OVER THE  
PACIFIC IS FORECAST TO PENETRATE FARTHER INLAND THROUGH THE  
PACIFIC NORTHWEST. MODELS HAVE GENERALLY ABANDONED THE PREVIOUS  
IDEA OF DEEPENING THIS TROUGH OVER THE SOUTHWEST BUT RATHER, GLIDE  
IT STEADILY EAST-SOUTHEAST THROUGH THE WESTERN U.S. INTO THE  
CENTRAL/SOUTHERN PLAINS BY THE WEEKEND. THIS PATTERN WOULD FAVOR  
THE FORMATION OF A FRONTAL WAVE/CLIPPER SYSTEM OVER THE CENTRAL  
PLAINS BY THE WEEKEND. MODELS HAVE GENERALLY SHOWN BETTER  
AGREEMENT TODAY REGARDING THE TIMING OF THIS CLIPPER SYSTEM, WITH  
A TENDENCY TO CONVERGE TOWARD THE ECMWF, WHICH IS IN BETWEEN THE  
SLOWER CMC AND THE FASTER GFS. BY LATE IN THE WEEKEND, MODEL  
CONSENSUS CONTINUES TO SUGGEST THAT THE CLIPPER WILL MOVE ACROSS  
THE SOUTHEAST AND THEN EXIT INTO THE ATLANTIC. THERE WAS A FASTER  
TREND IN THE MODELS TO PUSH THE CLIPPER OFF THE COAST, WHICH  
RESULTED IN A POTENTIALLY HEAVY RAINFALL AXIS TO BE NUDGED FARTHER  
SOUTH ALONG THE CENTRAL AND EASTERN GULF COAST EARLIER DURING THE  
WEEKEND. MEANWHILE, MODELS HAVE SHOWN VERY GOOD AGREEMENT ON A  
STEADY INCREASE OF MOISTURE TO REACH THE PACIFIC NORTHWEST LATE  
THIS WEEKEND.  
 
THE WPC MEDIUM-RANGE FORECASTS WERE COMPOSED BASED ON A COMPOSITE  
BLEND OF 40% 00Z ECMWF/EC MEAN, 40% 06Z GFS/GEFS AND 20% FROM THE  
00Z CMC/CMC MEAN. LESS OF THE GFS WAS USED ON DAY 5 TO ALLOW A  
SLOWER PROGRESSION OF THE CLIPPER SYSTEM. THE BLEND THEN  
TRANSITION TO MOSTLY A CONSENSUS OF THE ENSEMBLE  
MEANS BY DAY 7. THE RESULTS COMPARE WELL WITH WPC CONTINUITY,  
WITH REASONABLE TIMING DISCREPANCY ON FRONTAL POSITIONS ON DAY 7.  
 
   
..OVERVIEW AND WEATHER HIGHLIGHTS/THREATS
 
 
A DEEP CYCLONE IS SET TO LIFT FROM THE GREAT LAKES TO EASTERN  
CANADA THURSDAY INTO FRIDAY, OFFERING A THREAT FOR WRAPPING HEAVY  
SNOWS NORTH OF THE LOW TRACK. HIGH WINDS APPEAR LIKELY ON THE  
BACKSIDE OF THE CYCLONE ON THURSDAY ACROSS THE UPPER MIDWEST,  
ESPECIALLY ALONG THE SOUTH SHORE OF LAKE SUPERIOR. IN THE WARM  
SECTOR, PRE-FRONTAL CONVECTION WILL LIKELY SWEEP ACROSS THE  
EASTERN SEABOARD ON THURSDAY ALONG WITH A SEVERE WEATHER THREAT  
FOCUS OVER THE MID-ATLANTIC AS PER SPC WHILE A HEAVY RAINFALL  
THREAT SHOULD EXTEND FROM NORTHERN FLORIDA THROUGH THE COASTAL  
PLAINS OF GEORGIA AND THE CAROLINAS.  
 
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 OFF THE GULF  
COAST. 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.  
 
KONG/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  
 
HAZARDS:  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE PACIFIC NORTHWEST AND  
THE NORTHERN GREAT BASIN, MON, APR 4.  
- HEAVY RAIN ACROSS PORTIONS OF THE SOUTHEAST, SAT, APR 2.  
- HEAVY RAIN ACROSS PORTIONS OF THE SOUTHEAST AND THE  
MID-ATLANTIC, THU, MAR 31.  
- SEVERE WEATHER ACROSS PORTIONS OF THE SOUTHEAST, THE  
MID-ATLANTIC, AND THE CENTRAL APPALACHIANS, THU, MAR 31.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE LOWER  
MISSISSIPPI VALLEY, THE UPPER MISSISSIPPI VALLEY, AND THE NORTHERN  
PLAINS.  
- HIGH WINDS ACROSS PORTIONS OF THE GREAT LAKES AND THE UPPER  
MISSISSIPPI VALLEY, THU, MAR 31.  
 
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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