049  
FXUS02 KWBC 231901  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EDT SAT APR 23 2022  
 
VALID 12Z TUE APR 26 2022 - 12Z SAT APR 30 2022  
   
..OVERVIEW
 
 
AN UPPER TROUGH DIGGING INTO THE NORTHERN TIER AND TOWARD THE  
MIDWEST/OHIO VALLEY WILL STEADILY PUSH A COLD FRONT THROUGH THE  
EASTERN SEABOARD WHERE GENERALLY MODEST RAINFALL IS EXPECTED ON  
TUESDAY. MODEST CYCLOGENESIS FORECAST TO OCCUR NEAR/EAST OF NEW  
ENGLAND WILL LIKELY PROMOTE LINGERING PRECIPITATION FOR THE  
NORTHEAST AS THE WEEK PROGRESSES. MEANWHILE, MEAN TROUGHING IS  
LIKELY IN THE WEST WITH MULTIPLE SHORTWAVES TRACKING THROUGH,  
BRINGING PERIODS OF PRECIPITATION WHILE RIDGING IN BETWEEN WILL  
SPREAD WARM TEMPERATURES FROM THE SOUTHWEST TO SOUTHERN/CENTRAL  
PLAINS BY LATE WEEK.  
 
   
..MODEL GUIDANCE EVALUATION
 
 
MODEL GUIDANCE HAS REMAINED CONSISTENT WITH BETTER THAN AVERAGE  
AGREEMENT FOR THE ABOVE-MENTIONED PATTERN AT LEAST THROUGH DAY  
5/6. THE GFS AND GEFS CONTINUES TO SHOW A TENDENCY FOR A FASTER  
EXIT OF THE LOW OFF TO THE EAST OF NEW ENGLAND LATER NEXT WEEK  
THAN THE ECMWF AND CMC. THE SAME TENDENCY GENERALLY APPLIES TO  
THE MEAN TROUGH IN THE WEST.  
A SHORTWAVE REACHING THE NORTHWEST AROUND TUESDAY SHOULD CONTINUE  
ONWARD ACROSS THE CANADIAN ROCKIES, POSSIBLY FORMING A COMPACT  
UPPER LOW OVER ALBERT MIDWEEK WITH THE GFS BEING THE MOST  
PROMINENT AND FASTEST WITH THIS FEATURE. THIS FASTER EASTWARD  
PROGRESSION OF THE UPPER LOW IN THE GFS PROMOTES EARLIER  
CYCLOGENESIS TO OCCUR OVER THE CENTRAL PLAINS TOWARD THE UPPER  
MIDWEST LATE WEEK THAN IN THE ECMWF AND CMC SOLUTIONS.  
 
GIVEN THE RELATIVELY TYPICAL MODEL BIASES AS DISCUSSED ABOVE, THE  
WPC MEDIUM-RANGE FORECASTS WERE BASED ON A MULTI-MODEL CONSENSUS  
OF 40% FROM THE 00Z ECMWF/00Z EC MEAN, 40% FROM THE 06Z GFS/GEFS,  
AND 20% FROM THE 00Z CMC/CMC MEAN. ONLY ON LARGE WEIGHT TOWARD  
THE ENSEMBLE MEANS WAS APPLIED TO MITIGATE THE HIGHER UNCERTAINTY  
ON DAY 7. THE RESULTS WERE VERY COMPATIBLE WITH THE PREVIOUS  
FORECAST PACKAGE.  
 
   
..SENSIBLE WEATHER/THREATS
 
 
THE COLD FRONT MOVING ACROSS THE EASTERN SEABOARD AS THE PERIOD  
BEGINS ON TUESDAY WILL PROMOTE RAIN AND POSSIBLY THUNDERSTORMS  
ALONG IT. ITS REASONABLY FAST PROGRESSION SHOULD KEEP RAINFALL  
AMOUNTS IN THE LIGHT TO MODERATE RANGE. THEN AS SURFACE LOW  
PRESSURE CONSOLIDATES AND PIVOTS AROUND THE UPPER LOW,  
PRECIPITATION WILL REMAIN IN THE FORECAST ACROSS THE NORTHEAST  
THROUGH THE END OF THE WORKWEEK. THERE IS SOME POTENTIAL FOR  
HIGHER ELEVATIONS OF NEW ENGLAND TO RECEIVE SNOW WITH THIS  
PRECIPITATION ACTIVITY. PRECIPITATION DO NOT APPEAR TO BE  
PARTICULARLY HEAVY AT THIS TIME BUT WILL BE MONITORED DUE TO ITS  
LINGERING TENDENCY. MEANWHILE IN THE WEST, UNSETTLED WEATHER IS  
LIKELY AS SHORTWAVE ENERGY MOVES THROUGH THE MEAN TROUGH SOUTH OF  
A CLOSED UPPER LOW POSITIONED OFF BRITISH COLUMBIA THROUGH  
THURSDAY. GUIDANCE HAS CONTINUED TO INDICATE AN EPISODE OF RAIN  
AND HIGH ELEVATION SNOW TUESDAY-WEDNESDAY FROM THE PACIFIC  
NORTHWEST TO THE NORTHERN ROCKIES ASSOCIATED WITH THE SHORTWAVE  
ENERGY, WHICH WILL BE FOLLOWED BY ANOTHER EPISODE LATE WEEK IN THE  
SAME GENERAL VICINITY AS THE MAIN TROUGH/UPPER LOW PUSHES ONSHORE.  
BY FRIDAY, A GENERAL EXPANSION OF RAIN IS FORECAST FOR THE  
NORTHERN TO CENTRAL PLAINS SPREADING TOWARD THE MIDWEST AND THE  
OHIO VALLEY INTO SATURDAY AS A LOW PRESSURE SYSTEM IS FORECAST TO  
DEVELOP OVER THE CENTRAL PLAINS. THE FAST GFS SOLUTION IS NOT  
PREFERRED AT THIS POINT. MEANWHILE, SOME FORM OF WINTRY  
PRECIPITATION IS FORECAST FOR THE NORTHERN HIGH PLAINS INTO NORTH  
DAKOTA ON FRIDAY.  
 
THE CORE OF POST-FRONTAL COLD AIR IS FORECAST IN THE  
DAKOTAS/MIDWEST ON TUESDAY AND SPREADING INTO THE GREAT LAKES  
REGION BY WEDNESDAY-THURSDAY, WITH TEMPERATURES 10-25F BELOW  
AVERAGE. AS THE COLD FRONT SWEEPS ACROSS THE EAST, TEMPERATURES  
WILL TRANSITION FROM WARMER THAN NORMAL ON TUESDAY TO BELOW NORMAL  
MIDWEEK, THOUGH WITH SOME TEMPERATURE MODERATION. THE NORTHWEST  
SHOULD SEE NEAR TO SLIGHTLY BELOW AVERAGE TEMPERATURES, BUT BY  
LATE WEEK TEMPERATURES IN THE NORTHERN ROCKIES/PLAINS IS FORECAST  
TO COOL DOWN TO MUCH BELOW NORMAL LEVELS ESPECIALLY IN TERMS OF  
HIGHS WITH THE POSSIBILITY OF MORE POTENT TROUGHING ALOFT.  
MEANWHILE FARTHER SOUTH, RIDGING IN PLACE WILL SPREAD WARMER THAN  
NORMAL TEMPERATURES FROM THE SOUTHWEST/FOUR CORNERS STATES INTO  
NORTHERN AND CENTRAL PARTS OF THE PLAINS, WITH AFTERNOON  
TEMPERATURES SOARING INTO THE 90S IN MANY AREAS AHEAD OF THE  
DEVELOPING LOW PRESSURE SYSTEM.  
 
KONG/TATE/RAUSCH  
 
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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