402  
FXUS02 KWBC 150647  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
246 AM EDT MON APR 15 2019  
 
VALID 12Z THU APR 18 2019 - 12Z MON APR 22 2019  
 
...HEAVY RAINFALL AND SEVERE WEATHER THREAT FOR THE CENTRAL TO  
EASTERN U.S. LATER THIS WEEK...  
 
   
..OVERVIEW
 
 
PROGRESSIVE BUT AMPLIFIED PATTERN WILL SUPPORT A DYNAMIC SYSTEM  
MOVING THROUGH THE CENTRAL STATES THU/FRI INTO THE EAST BY THE  
WEEKEND BUT POSSIBLY TAKING UNTIL NEXT WEEK TO FULLY MOVE  
OFFSHORE. THE WEST WILL SEE A FRONT MOVE INTO WASHINGTON/OREGON  
EARLY FRIDAY AND THEN PROGRESS EASTWARD AND SOUTHWARD INTO THE  
PLAINS AND SOUTHERN ROCKIES LATE THIS WEEKEND INTO NEXT MONDAY.  
 
   
..GUIDANCE PREFERENCES
 
 
BLEND OF THE 18Z GFS/GEFS AND 12Z ECMWF/ECMWF ENSEMBLE MEAN  
OFFERED A REASONABLE STARTING POINT TO THE MEDIUM RANGE PERIOD,  
WITH A DETERMINISTIC-CENTERED BLEND INCLUDING THE UKMET/CANADIAN  
TO START AND A 2/5THS ENSEMBLE WEIGHTING BY NEXT MONDAY. THIS  
MAINTAINED GOOD CONTINUITY OVERALL AS THE PATTERN REMAINS FAIRLY  
WELL-HANDLED BY THE ENSEMBLES AFTER EARLIER UNCERTAINTIES. STILL,  
QUESTIONS REMAIN IN HOW THE EASTERN SYSTEM EVOLVES DEPENDING ON  
THE STRENGTH/TRACK OF MID-LEVEL SHORTWAVES NOT EASILY RESOLVED AT  
THIS LEAD TIME. ENSEMBLE CLUSTERING SUGGESTED A SLOWING OF THE  
FRONT ALONG OR JUST OFF THE EAST COAST WITH A NEW SURFACE LOW/WAVE  
DEVELOPING NEAR THE MID-ATLANTIC BEFORE TURNING NORTHEASTWARD.  
RESIDENCE TIME NEAR NEW ENGLAND SHOULD BE LIMITED DUE TO THE  
APPROACHING SYSTEM FROM THE WEST BY THAT TIME.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
MULTI-INCH RAINFALL TOTALS WITH LOCAL FLOODING ARE PROBABLE  
(ENHANCED IN EMBEDDED CONVECTION) ALONG/AHEAD OF THE FRONT OVER  
THE LOWER MISSISSIPPI VALLEY (POSSIBLY INTO PARTS OF THE SOUTHEAST  
AND MID-ATLANTIC) WITH LESSER AMOUNTS IN A LOCAL MAX AREA TO THE  
NORTH/NORTHEAST OF THE SURFACE LOW ACROSS WISCONSIN. CONSULT SPC  
FOR THE LATEST ON THE SEVERE WEATHER RISK. MILD TEMPERATURES WILL  
PRECEDE THE FRONT (10-15F ABOVE AVERAGE) TO BE REPLACED BY COOLER  
THAN AVERAGE TEMPERATURES AFTER ITS PASSAGE. THE NORTHWEST WILL  
SEE GENERALLY LIGHT PRECIPITATION ALONG A FRONT PUSH THROUGH THE  
GREAT BASIN AND CENTRAL ROCKIES THIS WEEKEND INTO NEXT MONDAY.  
 
FRACASSO  
 
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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