127  
FXUS02 KWBC 130641  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
241 AM EDT SAT APR 13 2019  
 
VALID 12Z TUE APR 16 2019 - 12Z SAT APR 20 2019  
   
..ANOTHER IN A SERIES OF DYNAMIC SPRING STORMS NEXT WEEK
 
 
   
..OVERVIEW
 
 
TROUGHING WILL PUSH THROUGH THE WEST EARLY IN THE WEEK AND DIVE  
THROUGH THE PLAINS AND INTO THE MIDWEST AS RIDGING COMES BACK TO  
BOTH COASTS TEMPORARILY. THIS SUPPORTS A STRONG/ROBUST SYSTEM  
LIFTING OUT OF THE SOUTHERN PLAINS INTO THE GREAT LAKES WITH A  
THREAT OF HEAVY RAIN, STRONG WINDS, AND SOME WINTRY WEATHER.  
 
   
..GUIDANCE PREFERENCES AND PREDICTABILITY ASSESSMENT
 
 
MOST OF THE MODELS/ENSEMBLES SHOW REASONABLE CLUSTERING TO START  
THE PERIOD (TUE) SO THAT A BLENDED/CONSENSUS SOLUTION SUFFICED. BY  
WED THE EAST-WEST TIMING SPREAD REMAINED IN PLACE FROM 24 HRS AGO  
THOUGH IT WAS NOT QUITE THE DOG'S BREAKFAST OF YESTERDAY AS THERE  
HAS BEEN SOME CONTRACTION WESTWARD IN THE QUICKER ECMWF MEMBERS  
AND EASTWARD IN THE SLOWER CANADIAN/GEFS MEMBERS. HOWEVER, PARENT  
MODEL AND CHILDREN MEMBERS (BOTH DETERMINISTIC AND ENSEMBLE)  
REMAINED SEPARATE IN EACH SYSTEM. AGAIN FAVORED A MOSTLY MIDDLE  
GROUND SOLUTION VERY NEAR THE 18Z FV3-GFS. AS THE SYSTEM SHOULD  
DEEPEN AND TURN EASTWARD THEN NORTHEASTWARD THU, ECMWF ENSEMBLE  
MEMBERS CONTINUED TO LEAD THE PACK WITH A QUICKER EXIT TO THE  
NORTHEAST, THOUGH THE TREND HAS BEEN SLOWER. OPTED TO DISCOUNT THE  
12Z ECMWF ENSEMBLE MEAN IN FAVOR OF THE SLOWER SOLUTIONS NEAR THE  
12Z ECMWF/GFS AS THE LOW PUSHES THROUGH MICHIGAN FRIDAY. BY NEXT  
SATURDAY, THE FRONT WILL PUSH TO THE COAST AND PERHAPS CONTINUE  
EASTWARD, BUT WITH THE POSSIBILITY OF SFC WAVE DEVELOPMENT THAT  
WOULD SLOW ITS EASTWARD PROGRESS.  
 
THE WEST WILL BE COMPARATIVELY QUIETER, WITH A WEAK FRONTAL  
PASSAGE WEDNESDAY THEN ANOTHER LATE FRIDAY. CONSENSUS POSITIONING  
SUFFICED VIA THE BLEND PREFERENCE IN THE EAST, WHICH WAS CLOSE TO  
CONTINUITY.  
 
   
..WEATHER HIGHLIGHTS/HAZARDS
 
 
SIGNIFICANT PRECIPITATION WILL AGAIN INCREASE STARTING WEDNESDAY  
AND CONTINUING INTO THURSDAY ACROSS THE MISSISSIPPI/MISSOURI  
VALLEYS INTO THE GREAT LAKES AS LOW PRESSURE STRENGTHENS OVER  
KANSAS. MULTI-INCH RAINFALL TOTALS ARE PROBABLE (ENHANCED IN  
EMBEDDED CONVECTION) IN SOME LOCATIONS OF THE WARM SECTOR AND  
PERHAPS TO THE NORTH/NORTHEAST OF THE LOW WITH ADDITIONAL NORTHERN  
STREAM SUPPORT. TEMPERATURES TO THE NORTH/NORTHWEST OF THE LOW MAY  
ONLY BE MARGINALLY COLD ENOUGH FOR SNOW DEPENDING ON THE AMOUNT OF  
COOLER AIR AVAILABLE. TEMPERATURES WILL LARGELY BE WITHIN 10-15  
DEGREES OF AVERAGE VALUES FOR MID-APRIL. THE NORTHERN/CENTRAL  
ROCKIES INTO THE NORTHERN PLAINS AND UPPER MIDWEST WILL GENERALLY  
BE COOLER THAN AVERAGE WHILE THE WEST AND EAST COASTS WILL  
GENERALLY BE MILDER THAN AVERAGE.  
 
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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