538  
FXUS02 KWBC 100655  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
155 AM EST SUN MAR 10 2019  
 
VALID 12Z WED MAR 13 2019 - 12Z SUN MAR 17 2019  
 
...HEAVY SNOW/WIND THREAT FOR THE NORTH-CENTRAL U.S. WEDNESDAY AND  
THURSDAY...  
 
...HEAVY RAIN/STRONG THUNDERSTORM THREAT FROM THE SOUTH-CENTRAL  
PLAINS/MS VALLEY TO THE MID-SOUTH/SOUTHEAST WEDNESDAY TO FRIDAY...  
 
   
..OVERVIEW
 
 
PATTERN WILL START QUITE ACTIVE IN THE MEDIUM RANGE WED/THU AS  
ANOTHER CENTRAL CONUS SYSTEM HEADS TOWARD THE GREAT LAKES WITH A  
POTPOURRI OF WEATHER THREATS TYPICAL OF A ROBUST SPRING STORM.  
THIS WILL SPREAD A LARGE AREA OF POTENTIALLY HEAVY RAIN/SEVERE  
CONVECTION AND RUNOFF THREAT FROM THE CENTRAL/SOUTHERN PLAINS  
THROUGH THE MID-SOUTH/SOUTHEAST AS MARGINALLY COLD AIR TO THE  
NORTH SUPPORTS A HEAVY SNOW/WIND THREAT FOR THE NORTH-CENTRAL  
ROCKIES/PLAINS AND UPPER MIDWEST. BY NEXT WEEKEND, THE PATTERN  
APPEARS MUCH QUIETER WITH HIGH PRESSURE FORECAST TO DOMINATE THE  
WESTERN/CENTRAL PARTS OF THE LOWER 48 AS BROAD TROUGHING LINGERS  
IN THE EAST.  
 
   
..GUIDANCE AND UNCERTAINTY ASSESSMENT
 
 
MOST OF THE GFS/ECMWF DETERMINISTIC/ENSEMBLE GUIDANCE CLUSTERED  
WELL THROUGH THE PERIOD SO THAT A BLEND COULD BE UTILIZED THROUGH  
ABOUT FRIDAY. FOR NEXT WEEKEND, PREFERRED A MOSTLY ENSEMBLE-BASED  
SOLUTION GIVEN DISAGREEMENT ON THE SHAPE/DETAILS OF THE UPPER  
TROUGH IN THE EAST AS WELL AS BACK OVER THE SOUTHWEST.  
 
   
..WEATHER HIGHLIGHTS AND HAZARDS
 
 
MAIN SYSTEM OF INTEREST IN THE MEDIUM RANGE WILL LIFT OUT  
SOUTHEASTERN COLORADO WEDNESDAY MORNING AS PRECIPITATION EXPANDS  
IN COVERAGE EASTWARD, FOCUSED ON THE CENTRAL/SOUTHERN PLAINS  
(NORTHERN TEXAS NORTHWARD) TUE/WED. TO THE EAST, BOUNDARY ACROSS  
THE GULF WILL LIFT NORTHWARD AS A WARM FRONT AND BRING WIDESPREAD  
RAINFALL AND EMBEDDED CONVECTION INTO THE MISSISSIPPI/TENNESSEE  
VALLEY WEDNESDAY THEN INTO ALABAMA/GEORGIA/SOUTHERN APPALACHIANS  
THURSDAY INTO EARLY FRIDAY. THE POTENTIAL FOR SEVERAL INCHES OF  
RAIN EXISTS OVER A LARGE AREA THAT WILL BE FURTHER REFINED OVER  
THE NEXT FEW DAYS. TO THE NORTH, COLD ENOUGH AIR WILL SUPPORT SNOW  
ON THE NORTHWEST/NORTH SIDE OF THE SURFACE LOW THAT WILL OCCUR  
WITH STRONG WINDS (I.E., POSSIBLE BLIZZARD CONDITIONS). A COLD  
RAIN (PERHAPS OVER AN INCH TO AN INCH AND A HALF) WILL FALL TO THE  
SOUTHEAST OF THE SURFACE LOW OVER SOME AREAS THAT HAVE RECEIVED  
SIGNIFICANT SNOW IN THE SHORT TERM (E.G., ND/SD/MN INTERSECTION).  
THE SURFACE LOW WILL DEPART THROUGH SOUTHERN CANADA FRIDAY AS  
COLDER AIR IS DRAGGED IN BEHIND IT ACROSS THE GREAT LAKES,  
ENHANCING LAKE-EFFECT SNOWS.  
 
TEMPERATURES WILL REMAIN BELOW AVERAGE IN THE WEST BUT MODERATE BY  
NEXT WEEKEND AS UPPER RIDGING SLOWLY NOSES INTO THE AREA. IN THE  
EAST, SEASONABLE TEMPERATURES WEDNESDAY WILL WARM UP AHEAD OF THE  
CENTRAL STATES' SYSTEM BY THURSDAY INTO FRIDAY, ONLY TO RETREAT  
BACK TO NEAR OR JUST BELOW CLIMO VALUES BY NEXT WEEKEND.  
 
FRACASSO/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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