262  
FXUS02 KWBC 152016  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
415 PM EDT FRI APR 15 2022  
 
VALID 12Z MON APR 18 2022 - 12Z FRI APR 22 2022  
   
..WEATHER PATTERN OVERVIEW
 
 
A RELATIVELY PROGRESSIVE PATTERN THROUGH THE MEDIUM-RANGE PERIOD  
WILL PERIODICALLY SEND FRONTS AND LOW PRESSURE SYSTEMS EASTWARD  
ACROSS THE NATION WITH SOME POTENTIAL FOR CYCLOGENESIS TO OCCUR  
OVER THE NORTHEAST WHERE A BROAD UPPER TROUGH TENDS TO PERSIST.  
THE FIRST SYSTEM IS FORECAST TO MOVE ACROSS THE GREAT LAKES ON  
MONDAY AND WILL LIKELY INTERACT WITH ANOTHER FRONTAL WAVE MOVING  
ACROSS THE DEEP SOUTH AND THEN POTENTIALLY PHASE OVER THE  
NORTHEAST ON TUESDAY. MEANWHILE, THE NEXT SYSTEM IS FORECAST TO  
MOVE INTO THE WEST COAST MONDAY-TUESDAY BEFORE HEADING ACROSS THE  
REST OF THE COUNTRY LATE NEXT WEEK WITH THE MAIN LOW PRESSURE  
CENTER LIKELY TRACKING NORTH OF THE GREAT LAKES. A THIRD SYSTEM  
FROM THE PACIFIC IS FORECAST TO REACH THE PACIFIC NORTHWEST ON  
WEDNESDAY AND APPEAR TO TAKE ITS TIME MOVING ACROSS THE WESTERN  
U.S. THROUGH LATE NEXT WEEK.  
 
   
..MODEL GUIDANCE EVALUATION
 
 
MODEL GUIDANCE SUITE THIS MORNING APPEARS TO SHOW REASONABLY GOOD  
AGREEMENT WITH THE AFOREMENTIONED SYNOPTIC PATTERN EVOLUTION  
THROUGH MUCH OF THE MEDIUM-RANGE PERIOD. BY LATE NEXT WEEK, MODEL  
DIFFERENCES ARE MOST NOTICEABLE ACROSS THE PLAINS WHERE THE  
ECMWF/EC MEAN DEVELOPS A SLIGHTLY STRONGER SURFACE LOW OVER THE  
SOUTHERN PLAINS WHILE THE GFS/GEFS EMPHASIZES THE NORTHERN STREAM  
LOW/FRONT. EARLIER IN THE WEEK, THE EC TENDS TO FAVOR A STRONGER  
LOW TO TRACK UP THE NEW ENGLAND COAST WHILE KEEPING THE NORTHERN  
STREAM LOW WEAKER. THE OPPOSITE IS TRUE WITH THE GFS SOLUTIONS.  
RECENT MODEL RUNS HAVE TRENDED TOWARD AN INTERMEDIATE SOLUTION  
WITH THIS NORTHERN-SOUTHERN STREAM INTERACTION, WHILE THE MOST  
RECENT GFS INDICATES A MUCH MORE ROBUST COASTAL CYCLOGENESIS. ON  
THE OTHER HAND, THE ECMWF TAKES THE LOW ON A MORE INLAND TRACK  
WHILE THE CMC INDICATES AN INTERMEDIATE SOLUTION. BY LATE NEXT  
WEEK, THE ECMWF HAS GRADUALLY SLOWED DOWN THE LOW PRESSURE SYSTEM  
MOVING THROUGH THE GREAT LAKES TO BETTER AGREE WITH THE GFS AND  
CMC SOLUTIONS.  
 
THEREFORE THE WPC MEDIUM-RANGE FORECAST PACKAGE WAS A  
MULTI-MODEL/ENSEMBLE CONSENSUS CONSISTING OF 40% 00Z ECMWF/EC  
MEAN, 40% 06Z GFS/GEFS, AND 20% FROM THE 00Z CMC/CMC MEAN, WITH  
MORE WEIGHTS GIVEN TO THE ENSEMBLE MEANS ON DAY 7.  
 
   
..SENSIBLE WEATHER/THREATS
 
 
IN THE PRECIPITATION DEPARTMENT, THE WEST COAST REGION IS EXPECTED  
TO REMAIN RATHER UNSETTLED WITH TWO WELL-DEFINED EVENTS. THE  
FIRST ROUND OF RAIN AND MOUNTAIN SNOW IS EXPECTED LATE MONDAY INTO  
TUESDAY FROM NORTHERN CALIFORNIA TO WASHINGTON STATE, AND THE  
SECOND ARRIVING THURSDAY AND EARLY FRIDAY, EXTENDING FARTHER SOUTH  
INTO CENTRAL CALIFORNIA AND ALSO AFFECTING AREAS TO THE NORTH.  
THIS WILL BE HIGHLY BENEFICIAL PRECIPITATION TO DROUGHT-STRICKEN  
AREAS OF CALIFORNIA, WITH THE POTENTIAL FOR UP TO THREE INCHES OF  
RAIN IN SOME AREAS NEXT WEEK, AND 1-2 FEET OF SNOW FOR THE SIERRA.  
ELSEWHERE ACROSS THE CONTINENTAL U.S., SHOWERS AND THUNDERSTORMS  
WILL BE EXITING THE EAST COAST REGION EARLY IN THE WEEK, FOLLOWED  
BY DRY WEATHER AS HIGH PRESSURE SETTLES INTO THE REGION. ANOTHER  
ROUND OF ORGANIZED SHOWERS AND STORMS IS LIKELY ACROSS THE CENTRAL  
U.S. BY MIDWEEK AS GULF MOISTURE RETURNS AHEAD OF THE ORGANIZING  
STORM SYSTEM OVER THE CENTRAL PLAINS. FOR THE EAST COAST,  
POTENTIAL NORTHERN-SOUTHERN STREAM INTERACTION AND PHASING COULD  
POSSIBLY BRING SOME HEAVY WET SNOW ACROSS INTERIOR NEW ENGLAND  
TUESDAY INTO EARLY WEDNESDAY WITH ANTECENDENT HEAVY RAIN POSSIBLE  
NEAR THE CAROLINA COASTS ON MONDAY, REACHING THE NEW ENGLAND COAST  
ON TUESDAY.  
 
TEMPERATURES ARE EXPECTED TO REMAIN RATHER CHILLY FROM THE  
NORTHERN PLAINS TO THE GREAT LAKES AND APPALACHIANS THROUGH MUCH  
OF THE UPCOMING WEEK, AND THESE BELOW AVERAGE READINGS SHOULD ALSO  
INCLUDE MUCH OF THE EAST COAST REGION THROUGH ABOUT WEDNESDAY AS  
THE COLD CANADIAN SURFACE HIGH GOVERNS THE WEATHER PATTERN. ON  
THE CONTRARY, WARM CONDITIONS ARE CURRENTLY EXPECTED ACROSS MUCH  
OF THE INTERIOR WESTERN U.S. FOR THE MAJORITY OF THE FORECAST  
PERIOD, WITH ABOVE NORMAL READINGS PROBABLE ACROSS THE CENTRAL AND  
SOUTHERN PLAINS ON WEDNESDAY AHEAD OF THE COLD FRONT.  
TEMPERATURES SHOULD ALSO MODERATE FOR THE EASTERN U.S. BY THURSDAY  
AS THE SURFACE HIGH MOVES OFF THE COAST AND WARMER SOUTHERLY FLOW  
COMMENCES.  
 
KONG/HAMRICK  
 
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 CALIFORNIA, THE PACIFIC  
NORTHWEST, AND THE NORTHERN GREAT  
BASIN, MON, APR 18 AND WED-THU, APR 20-APR 21.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE NORTHEAST, TUE, APR  
19.  
- HEAVY RAIN ACROSS PORTIONS OF THE MID-ATLANTIC, MON, APR 18.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE SOUTHEAST,  
THE MISSISSIPPI VALLEY, AND THE  
NORTHERN PLAINS.  
- FLOODING LIKELY ACROSS PORTIONS OF THE SOUTHEAST.  
- HIGH WINDS ACROSS PORTIONS OF THE PLAINS, TUE, APR 19.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE UPPER  
MISSISSIPPI VALLEY, THE NORTHERN  
PLAINS, AND THE NORTHERN ROCKIES, MON-TUE, APR 18-APR 19.  
 
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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