988  
FXUS02 KWBC 220701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 AM EDT TUE MAR 22 2022  
 
VALID 12Z FRI MAR 25 2022 - 12Z TUE MAR 29 2022  
   
..OVERVIEW
 
 
AN AMPLIFIED UPPER LEVEL PATTERN IS EXPECTED DURING THE MEDIUM  
RANGE PERIOD, BEGINNING FRIDAY WITH TROUGHING ACROSS THE EAST AND  
RIDGING IN THE WEST. ADDITIONAL IMPULSES COMING INTO THE TROUGH  
WILL REINFORCE IT AT LEAST FOR THE NORTHEASTERN U.S. THROUGH EARLY  
NEXT WEEK, WITH COOL TEMPERATURES AND PERIODIC LIGHT  
PRECIPITATION. MEANWHILE THE RIDGE SHOULD BE GRADUALLY PUSHED  
TOWARD THE CENTRAL U.S., SPREADING WARMER TEMPERATURES THERE AFTER  
POTENTIALLY RECORD-SETTING WARMTH IN THE WEST, AS TROUGHING  
APPROACHES FROM THE EAST PACIFIC. THERE IS UNCERTAINTY IN THE  
TROUGH'S TIMING AND AMPLITUDE, BUT IT SHOULD CAUSE INCREASED  
PRECIPITATION CHANCES AND COOLER TEMPERATURES IN THE WEST WHEN IT  
COMES IN, WITH POTENTIAL FOR A SURFACE LOW PRESSURE SYSTEM TO  
STRENGTHEN IN THE PLAINS BUT THE END OF THE PERIOD NEXT TUESDAY.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODEL GUIDANCE FROM THE 12/18Z YESTERDAY CYCLE BEGINS WITH  
GENERALLY GOOD AGREEMENT FOR THE LARGE SCALE PATTERN, WITH TYPICAL  
DIFFERENCES WITH SHORTWAVES EMBEDDED WITHIN THE TROUGH OVER THE  
EASTERN THIRD OF THE COUNTRY. AN INITIAL COASTAL LOW JUST OFF NEW  
ENGLAND EARLY FRIDAY CLUSTERS WELL AMONG GUIDANCE. MODELS SHOW  
STRONGER ENERGY WITH THE POSSIBILITY OF A SMALL CLOSED UPPER LOW  
EARLY SATURDAY LIKELY OVER THE GREAT LAKES/OHIO VALLEY, BUT WITH  
SOME LATITUDINAL VARIATIONS IN HOW FAR SOUTH THE TROUGH/LOW  
REACHES--ECMWF RUNS HAVE GENERALLY BEEN AMONG THE FARTHEST SOUTH.  
BUT THE BIGGER OUTLIER WITH THIS FEATURE WAS LIKELY THE 12Z UKMET,  
WHICH SEPARATED STREAMS BY SUNDAY TO CREATE A SOUTHERN STREAM LOW  
IN THE SOUTHEAST, SO LEANED AWAY FROM THAT SOLUTION. THERE IS  
GENERALLY GOOD AGREEMENT IN PRINCIPLE THAT TROUGHING WILL LIFT  
GRADUALLY EARLY IN THE WORKWEEK FOR THE SOUTHEAST, BUT WITH SOME  
SEMBLANCE REMAINING IN THE NORTHEAST.  
 
HOWEVER, FARTHER WEST, MORE SIGNIFICANT DIFFERENCES IN THE PATTERN  
ARISE. WHILE EARLY AGREEMENT FOR RIDGING SHIFTING EASTWARD IS  
REASONABLY GOOD, THERE ARE NOTABLE TIMING ISSUES WITH INDIVIDUAL  
MODELS AS WELL AS ENSEMBLE MEANS WITH THE INCOMING TROUGHING, AS  
WELL AS DIFFERENCES IN POTENTIAL STREAM SEPARATION AND ITS TIMING.  
THE 12Z AND NEWER 00Z ECMWF SHOW A MUCH SLOWER CLOSED LOW COMPARED  
TO MOST OF THE RECENT GUIDANCE AND ITS ENSEMBLE MEAN, AFTER ITS  
PREVIOUS RUNS WERE AMONG THE FASTER SOLUTIONS. IN CONTRAST, GFS  
RUNS ARE NOW FASTER WITH AN INLAND TRACK AND MORE PHASED, AFTER  
RUNS ABOUT A DAY AGO SHOWED AN UPPER LOW HOVERING IN THE PACIFIC  
LONGER. THIS FLIP-FLOP AS WELL AS INDIVIDUAL ENSEMBLE MEMBER  
SPREAD BECOMING VERY BROAD LATE IN THE PERIOD LEADS TO FAIRLY LOW  
CONFIDENCE IN THE TROUGH'S TIMING. THE CMC AND ITS MEAN ARE FASTER  
AND MORE CLUSTERED WITH THE GFS/GEFS, BUT DID THINK THE 12Z CMC  
ENSEMBLE MEAN MAY BE SLIGHTLY FAST WITH THE TROUGH AXIS BY NEXT  
TUESDAY.  
 
THUS THE WPC MEDIUM RANGE FORECAST FAVORED AN OPERATIONAL MODEL  
BLEND AT THE BEGINNING OF THE PERIOD. LESSENED THE PROPORTION  
ESPECIALLY OF THE ECMWF BY THE END OF THE PERIOD AS BETTER  
CLUSTERING SEEMED TO BE WITH THE ECMWF MEAN, GFS RUNS, GEFS MEANS,  
AND CMC. GIVEN THE UNCERTAINTY, SHIFTS IN THE FORECAST ARE  
POSSIBLE IF NOT LIKELY PARTICULARLY WITH THE TIMING OF THE TROUGH  
AND THE ASSOCIATED FRONTS AHEAD OF IT.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
SNOW MAY LINGER IN MAINE ON FRIDAY AS A COASTAL LOW FORMS. THEN  
SHORTWAVE ENERGY AND WEAK LOW PRESSURE/FRONTAL SYSTEMS COULD LEAD  
TO LIGHT PRECIPITATION SPREADING ACROSS THE NORTHEASTERN QUADRANT  
OF THE COUNTRY THROUGH EARLY NEXT WEEK, FROM THE GREAT LAKES  
REGION TO THE CENTRAL/NORTHERN APPALACHIANS AND NORTHEAST LATE  
WEEK INTO THE WEEKEND. SOME OF THIS PRECIPITATION WILL BE IN THE  
FORM OF SNOW IN HIGHER ELEVATIONS AND NORTHERN LATITUDES, AND  
GUSTY WINDS ARE ALSO POSSIBLE. PRECIPITATION AHEAD OF THE  
APPROACHING EASTERN PACIFIC UPPER TROUGH IS LIKELY TO REACH THE  
PACIFIC NORTHWEST AROUND FRIDAY AND THEN SPREAD ACROSS MORE OF THE  
WEST THEREAFTER. MOST OF THIS ACTIVITY SHOULD BE IN THE LIGHT TO  
MODERATE RANGE BUT SOME LOCALLY HEAVIER TOTALS COULD BE POSSIBLE  
DEPENDING ON EXACT SYSTEM DETAILS. COVERAGE AND INTENSITY OF THIS  
PRECIPITATION BECOMES INCREASINGLY UNCERTAIN BY LATE WEEKEND INTO  
EARLY NEXT WEEK.  
 
UNSEASONABLY WARM TEMPERATURES WILL BUILD AND EXPAND UNDERNEATH  
UPPER RIDGING FROM THE WESTERN U.S. INTO THE PLAINS. HIGHS THAT  
ARE 10-20F ABOVE NORMAL WILL BE COMMON OVER CALIFORNIA AND THE  
GREAT BASIN/SOUTHWEST FRIDAY, WITH SOME PLUS 20-25F ANOMALIES  
APPEARING IN THE GREAT BASIN SATURDAY AND MOVING TO THE  
NORTHERN/CENTRAL HIGH PLAINS EARLY NEXT WEEK AS THE UPPER RIDGE  
AXIS SHIFTS. DAILY RECORD TEMPERATURES COULD BE TIED OR SET ACROSS  
CALIFORNIA AND EASTWARD. TEMPERATURES IN THE WEST ARE LIKELY TO  
COOL CLOSER TO NORMAL BY AROUND MONDAY BUT THE EXACT TIMING WILL  
DEPEND ON THE TROUGH'S MOVEMENT INLAND. MEANWHILE THE EAST SHOULD  
SEE NEAR TO SLIGHTLY BELOW AVERAGE TEMPERATURES GIVEN MEAN UPPER  
TROUGHING, WITH COOLEST TEMPERATURES OF 10-15F BELOW NORMAL IN THE  
CENTRAL APPALACHIANS FOR THE WEEKEND AND IN THE GREAT LAKES EARLY  
NEXT WEEK.  
 
TATE  
 
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  
 
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/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML  
 

 
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page