073  
FXUS02 KWBC 192029  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
427 PM EDT TUE APR 19 2022  
 
VALID 12Z FRI APR 22 2022 - 12Z TUE APR 26 2022  
 
...WEEKEND STORM LIKELY TO BRING HEAVY PRECIPITATION/STRONG WINDS  
TO THE NORTHERN PLAINS AND A HEAVY RAINFALL THREAT TO SOME AREAS  
FARTHER SOUTH...  
   
..WEATHER PATTERN OVERVIEW
 
 
THE UPPER LEVEL PATTERN OVER THE CONTINENTAL U.S. WILL BECOME MORE  
AMPLIFIED BY THE END OF THE WEEK AND INTO THE WEEKEND AS A LARGE  
SYNOPTIC SCALE PACIFIC TROUGH PROGRESSES THROUGH THE WEST,  
SUPPORTING SURFACE CYCLOGENESIS ACROSS THE HIGH PLAINS BY FRIDAY  
NIGHT. AN EMBEDDED UPPER LOW SHOULD TRACK NORTHEASTWARD THROUGH  
THE NORTHERN PLAINS DURING THE WEEKEND, BRINGING STRONG LOW  
PRESSURE THROUGH THE THIS REGION AND THE UPPER MIDWEST. THIS  
STORM SHOULD PRODUCE SIGNIFICANT SNOWFALL OVER SOME AREAS IN THE  
COLD SECTOR ALONG WITH VARYING INTENSITY OF RAINFALL TO THE EAST  
AS WELL AS POTENTIALLY HEAVY RAINFALL FARTHER SOUTH OVER THE  
PLAINS/MISSISSIPPI VALLEY ALONG THE TRAILING WAVY FRONT.  
MEANWHILE, A DOWNSTREAM UPPER RIDGE AXIS BUILDING OVER THE EASTERN  
U.S. SHOULD LEAD TO A CONSIDERABLE WARMING TREND OVER SOME AREAS  
FOR THE WEEKEND BUT COOL HIGH PRESSURE MAY PERSIST FOR A TIME OVER  
THE NORTHEAST/NORTHERN MID-ATLANTIC. ANOTHER PACIFIC UPPER TROUGH  
SHOULD APPROACH THE NORTHWESTERN U.S. BY THE BEGINNING OF NEXT  
WEEK.  
   
..MODEL GUIDANCE EVALUATION
 
 
THE UPDATED FORECAST UTILIZED A BLEND OF 00Z/06Z OPERATIONAL  
MODELS EARLY AND THEN TRENDED TO A COMBINATION OF MODELS AND 06Z  
GEFS/00Z ECMWF MEANS. THIS APPROACH YIELDED ONLY TYPICAL  
RUN-TO-RUN ADJUSTMENTS THROUGH MOST OF THE PERIOD. BY EARLY NEXT  
WEEK, MOST GUIDANCE HAS DISPLAYED A TREND TOWARD A SLOWER/MORE  
ELONGATED UPPER TROUGH BEHIND THE STRONG NORTHERN TIER  
STORM--RESULTING IN A SLOWER AND MORE WAVY TRAILING SURFACE FRONT  
THAT WAS REFLECTED IN THE UPDATE. 06Z/12Z GFS RUNS HAVE GONE BACK  
TO A FASTER PROGRESSION THOUGH. AS FOR THE STRONG NORTHERN TIER  
STORM, THERE IS STILL A FAIR DEGREE OF TIMING SPREAD WITH THE GFS  
FASTEST AND UKMET/CMC SLOWEST. MULTI-RUN TRENDS SHOW THE GFS/GEFS  
COMING BACK TO THE ECMWF/ECMWF MEAN SO AT THE VERY LEAST THE FAST  
SIDE OF THE SPREAD APPEARS LESS LIKELY. THUS FAR TRENDS HAVE NOT  
BEEN PRONOUNCED ENOUGH TO INCLUDE MORE THAN MINORITY WEIGHT OF THE  
UKMET/CMC. SOME TRACK SPREAD IS ALSO EVIDENT AND FORECAST WEATHER  
OVER SOME AREAS WILL BE VERY SENSITIVE TO SPECIFICS. FOR THE  
UPPER TROUGH NEARING THE WEST COAST BY LATE IN THE PERIOD,  
MODELS/ENSEMBLES ARE GOOD AT DEPICTING THE OVERALL FEATURE IN  
PRINCIPLE BUT VARY WITH SOME DETAILS. THE 12Z GFS IS PARTICULARLY  
STRONG WITH SOME LEADING SHORTWAVE ENERGY REACHING THE WEST BY  
LATE SUNDAY-MONDAY. THIS ULTIMATELY AFFECTS ITS PROGRESSION OF  
THE CENTRAL U.S. TROUGH.  
   
..SENSIBLE WEATHER/THREATS
 
 
CONFIDENCE CONTINUES TO IMPROVE FOR THE GENERAL FORECAST OF A  
STRONG STORM EMERGING FROM THE ROCKIES AND TRACKING INTO THE  
DAKOTAS/UPPER MIDWEST LATE THIS WEEK INTO THE WEEKEND. BEST  
POTENTIAL FOR SIGNIFICANT SNOWFALL WILL BE FROM FAVORED TERRAIN  
WITHIN THE GREAT BASIN/NORTH-CENTRAL ROCKIES AND THEN THROUGH  
EASTERN MONTANA/NORTHEASTERN WYOMING AND THE WESTERN HALF OF NORTH  
DAKOTA (TO THE IMMEDIATE WEST OF THE SURFACE LOW TRACK). STRONG  
WINDS AROUND THE LOW COULD PRODUCE BLIZZARD CONDITIONS FOR SOME  
AREAS IF MODEL FORECASTS PERSIST. THERE IS STILL SOME UNCERTAINTY  
FOR THE TRACK AND SPEED OF THE STORM, SO CONTINUE TO MONITOR  
FORECASTS FOR REFINEMENTS TO THE DETAILS. LOCATIONS IN WARMER AIR  
TO THE EAST MAY SEE RAINFALL OF VARYING INTENSITY, INCLUDING SOME  
POCKETS OF LOCALLY MODERATE TO HEAVY ACTIVITY.  
 
THE WAVY COLD FRONT EXTENDING SOUTHWARD FROM THE STORM MAY PROVIDE  
A FOCUS FOR HEAVY SHOWERS AND THUNDERSTORMS FROM SUNDAY INTO THE  
EARLY PART OF THE NEXT WORK WEEK, WITH ADDED CONTRIBUTION FROM  
LINGERING UPPER TROUGH ENERGY AND INPUT FROM GULF MOISTURE  
ADVECTING NORTHWARD AHEAD OF THE FRONT. THIS WILL LIKELY BE IN  
THE FORM OF MULTIPLE MESOSCALE CONVECTIVE COMPLEXES WITH REPEATING  
ROUNDS OF CONVECTION/TRAINING, AND SOME STRONG TO SEVERE STORMS  
ARE ALSO POSSIBLE. CURRENTLY THE BEST POTENTIAL FOR HIGHEST  
RAINFALL TOTALS EXISTS FROM PARTS OF THE SOUTHERN HALF OF THE  
PLAINS INTO OR A BIT SOUTH OF THE MIDDLE MISSISSIPPI VALLEY.  
 
THE UPPER TROUGH APPROACHING THE WEST LATE IN THE PERIOD SHOULD  
BRING LIGHT TO MODERATE PRECIPITATION TO THE PACIFIC NORTHWEST  
EARLY NEXT WEEK.  
 
EXPECT UNSEASONABLY COLD TEMPERATURES TO PERSIST OVER FAR NORTHERN  
PARTS OF THE PLAINS THROUGH THE PERIOD WITH NORTH DAKOTA IN  
PARTICULAR SEEING HIGHS 15-30F BELOW NORMAL FOR MULTIPLE DAYS.  
THE WEST WILL SEE MORE VARIABLE TEMPERATURES, WITH MINUS 5-15F  
ANOMALIES LATE WEEK INTO THE WEEKEND BUT FOLLOWED BY A  
WEST-TO-EAST MODERATING TREND WITH INCREASING COVERAGE OF ABOVE  
NORMAL READINGS EARLY NEXT WEEK. CLOUDS/PRECIPITATION MAY BRING  
BELOW NORMAL HIGHS TO THE PACIFIC NORTHWEST NEXT TUESDAY THOUGH.  
A MAJOR WARMING TREND IS LIKELY FOR THE CENTRAL/SOUTHERN PLAINS ON  
FRIDAY AND THEN MUCH OF THE EASTERN HALF OF THE NATION GOING INTO  
THE WEEKEND. CENTRAL PLAINS LOCATIONS COULD SEE HIGHS UP TO  
20-30F ABOVE NORMAL ON FRIDAY. PLUS 10-20F ANOMALIES SHOULD BE  
MORE COMMON FARTHER EAST. ALSO HUMIDITY LEVELS SHOULD INCREASE IN  
RESPONSE TO DEEP SOUTHERLY FLOW AHEAD OF THE CENTRAL U.S. STORM  
SYSTEM. ONE EXCEPTION TO THE EASTERN WARMTH SHOULD BE OVER THE  
NORTHEAST/NORTHERN MID-ATLANTIC WHERE COOL SURFACE HIGH  
PRESSURE/RIDGING MAY PREVAIL FOR MULTIPLE DAYS. A BACK DOOR FRONT  
EXPECTED TO SETTLE OVER THE MID-ATLANTIC COULD PROVIDE A SHARP  
CONTRAST BETWEEN COOL AIR TO THE NORTH AND WARMTH TO THE SOUTH AND  
WEST.  
 
RAUSCH/HAMRICK  
 
HAZARDS:  
- HEAVY PRECIPITATION ACROSS PORTIONS OF NORTHWESTERN WYOMING,  
SOUTHWESTERN MONTANA, AND THE WASATCH OF UTAH, FRI, APR 22.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE NORTHERN PLAINS INTO  
NORTHERN MINNESOTA, FRI-SAT, APR 22-APR 23.  
- HEAVY SNOW ACROSS PORTIONS OF THE NORTHERN HIGH PLAINS, THE  
BLACK HILLS, AND INTO NEARBY ROCKIES, FRI-SAT, APR 22-APR 23.  
- HEAVY RAIN FROM ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN  
PLAINS INTO THE MID-MISSISSIPPI VALLEY AND THE MIDWEST, SUN-MON,  
APR 24-APR 25.  
- HEAVY RAIN ACROSS PORTIONS OF THE UPPER MISSISSIPPI VALLEY,  
FRI-SAT, APR 22-APR 23.  
- SEVERE WEATHER ACROSS PORTIONS OF CENTRAL TO NORTHERN PLAINS,  
FRI, APR 22.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE SOUTHEAST.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE LOWER  
SAVANNAH RIVER AND NEAR/WEST OF JACKSON, MISSISSIPPI.  
- FLOODING LIKELY ACROSS PORTIONS OF CENTRAL SOUTH CAROLINA.  
- HIGH WINDS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN ROCKIES  
INTO CENTRAL AND SOUTHERN HIGH PLAINS, FRI, APR 22.  
- HIGH WINDS ACROSS PORTIONS OF THE NORTHERN HIGH PLAINS AND INTO  
THE NORTHERN ROCKIES, FRI-SUN, APR 22-APR 24.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE NORTHERN  
PLAINS, SAT-TUE, APR 23-APR 26.  
- ENHANCED WILDFIRE RISK ACROSS PORTIONS OF THE CENTRAL AND  
SOUTHERN ROCKIES INTO THE NEARBY HIGH PLAINS, FRI, APR 22.  
- ENHANCED WILDFIRE RISK ACROSS PORTIONS OF THE SOUTHERN HIGH  
PLAINS INTO THE FOOTHILLS OF THE SOUTHERN ROCKIES, SAT, APR 23.  
 
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  
 

 
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page