681  
FXUS02 KWBC 240700  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 AM EDT SUN MAR 24 2019  
 
VALID 12Z WED MAR 27 2019 - 12Z SUN MAR 31 2019  
   
..OVERVIEW
 
 
A CLOSED EASTERN PACIFIC UPPER TROUGH WILL REACH THE WEST MIDWEEK,  
WITH HEIGHT FALLS WORKING EASTWARD OVER THE NATION THU-NEXT SUN.  
SURFACE FRONTS IN THE WEST WILL SUPPORT SOME HEAVY PRECIPITATION  
INCLUDING HEAVY ELEVATION SNOWS, AND LOW DEVELOPMENTS IN THE  
PLAINS AND SUBSEQUENT MOVEMENT THROUGH THE MS VALLEY/MIDWEST MAY  
COMBINE WITH A SURGE OF DEEPENING MOISTURE/WARMTH FROM THE GULF OF  
MEXICO TO FUEL SOME ENHANCED RAIN/THUNDERSTORMS IN THOSE AREAS  
LATER WEEK. THE PATTERN ALSO INCLUDES A RISK OF WRAP-AROUND  
POST-FRONTAL SNOWS ON THE COOLED NORTHWEST PERIPHERY OF THE MAIN  
PRECIPITATION SHIELD.  
   
..GUIDANCE ASSESSMENT/PREFERENCES
 
 
A MULTI-MODEL BLEND HAS BEEN WORKING WELL INTO DAY 3/4 FOR THE  
LARGE-SCALE FEATURES WHILE DE-EMPHASIZING THE SMALL-SCALE  
DIFFERENCES IN THE FORECAST MODELS WERE IN GENERAL AGREEMENT FOR  
THE UPPER LOW IN THE EASTERN PACIFIC MOVING EASTWARD INTO THE  
CONUS. PREFER AN ENSEMBLE MEAN FORECAST APPROACH DAYS 5-7 IN A  
PERIOD OF GROWING FORECAST SPREAD, LEANING MORE ON ECMWF ENSEMBLE  
MEAN TO MAINTAIN MAX WPC CONTINUITY.  
   
..WEATHER HIGHLIGHTS AND HAZARDS
 
 
WITH THE UPPER TROUGH/LOW APPROACHING THE WEST, A COUPLE OF FRONTS  
WILL MAKE THEIR WAY THROUGH THE WEST AND SOME HEAVY PRECIPITATION  
IS EXPECTED WED/THU. HEAVY VALLEY RAIN/MOUNTAIN SNOWS WILL  
THREATEN NORTHERN CALIFORNIA/OREGON THROUGH THE NORTHERN ROCKIES,  
WITH HEAVY SNOW FORECAST FOR THE CENTRAL ROCKIES INTO LATER WEEK.  
AS THE TROUGH ENERGY EJECTS OUT THROUGH THE WEST, IT IS EXPECTED  
TO INDUCE CYCLO/FRONTOGENESIS IN THE PLAINS. THIS PLUS ANOTHER  
COLD FRONT DROPPING SOUTHWARD OUT OF CANADA IN TANDOM WITH  
DEEPENING LEAD RETURN FLOW FROM THE GULF OF MEXICO WOULD FUEL AN  
EXPANDING RISK OF ENHANCING RAINS/CONVECTION. THE EMERGING HEAVY  
RAIN AREA THREATENS AREAS OF THE MISSISSIPPI VALLEY/MIDWEST (WHERE  
FLOODING IS ONGOING) HEADING INTO NEXT WEEKEND. UNCERTAINTY  
REMAINS REGARDING HEAVIEST RAINFALL AMOUNTS/PLACEMENT, BUT THE  
GUIDANCE SIGNAL FOR DEVELOPMENT CONTINUES TO GROW. IN THE COLD AIR  
BEHIND THE AFOREMENTIONED COLD FRONT COMING FROM CANADA,  
LATE-SEASON SNOW IS POSSIBLE IN THE NORTHERN/CENTRAL PLAINS TO  
MIDWEST.  
 
SCHICHTEL  
 
ADDITIONAL 3-7 DAY HAZARDS INFORMATION CAN BE FOUND ON THE WPC  
MEDIUM RANGE HAZARDS CHART AT:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, 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/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML  
 

 
 
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