684  
FXUS02 KWBC 280615  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
114 AM EST WED FEB 28 2018  
 
VALID 12Z SAT MAR 03 2018 - 12Z WED MAR 07 2018  
 
...WRN US STORM THIS WEEKEND LIFTS TO THE N-CENTRAL US/GREAT LAKES  
EARLY-MID NEXT WEEK...  
 
   
..PATTERN OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
AN UPPER TROUGH/LOW SWINGS OVER THE WRN US THIS WEEKEND WITH SOME  
HEAVY SNOWS FOCUSING FROM THE SIERRA THROUGH THE ROCKIES. THIS  
OCCURS AS ANOTHER STORM CONTINUES ITS PUSH WELL OFF THE EAST  
COAST. BETWEEN THESE SYSTEMS...WARMING UPPER RIDGING WILL SLIDE  
EASTWARD OVER THE EAST-CENTRAL US. THE WRN US SYSTEM LIFTS  
NORTHEASTWARD TO THE N-CENTRAL US EARLY NEXT WEEK. THIS SPREADS  
SNOW TO THE NRN PLAINS AND UPPER MIDWEST/GREAT LAKES...WITH WIND  
DRIVEN SNOW AND HAZARDOUS CONDITIONS. FARTHER  
SOUTH...RAIN/CONVECTION MEANWHILE EXPANDS FROM ERN TX AND LOWER  
MS/TN VALLEYS NORTHEASTWARD OVER THE EAST WITH TRAILING COLD  
FRONTAL APPROACH. GFS/ECMWF SOLUTIONS REMAIN VIABLE OPTIONS  
THROUGH THIS PERIOD TEAMED WITH COMPATABLE GEFS/ECMWF ENSEMBLE  
MEANS. THUS...THE PATTERN SEEMS TO OVERALL OFFERS ABOVE NORMAL  
PREDICTABILITY.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
AN UPPER TROUGH/LOW AND SURFACE FRONT WILL BRING IN COLDER  
TEMPERATURES...WINDY CONDITIONS AND MODEST TO LOCALLY HEAVIER  
RAIN/SNOW POTENTIAL OVER THE WEST. SNOW LEVELS WILL LOWER AS THE  
WEEKEND UPPER TROUGH SWINGS THROUGH. TEMPERATURES WILL RANGE TO  
WELL BELOW AVERAGE AND SOME RECORD LOWS ARE POSSIBLE. CONVERSELY  
AHEAD OF THE FRONT...TEMPERATURES WILL WARM ABOVE AVERAGE BY ABOUT  
10-20 DEGREES EAST OF THE ROCKIES THROUGH THE PLAINS THIS WEEKEND.  
 
PRECIPITATION INCREASINGLY DEVELOPS/SPREADS FROM THE CENTRAL TO  
ERN US AHEAD OF THE UPPER TROUGH AND SURFACE FRONT EARLY TO MID  
NEXT WEEK WITH DEEPEST GULF MOISTURE OVER THE WET LOWER MS/TN  
VALLEYS AND CENTRAL GULF COAST STATES. TO THE NORTH...POTENTIAL  
EXISTS FOR A HAZARDOUS SNOWSTORM IN THE COLDER AIR NORTH OF THE  
LOW WITH WINDY CONDITIONS AROUND THE DEEPENING LOW FOR THE  
DAKOTAS/UPPER MIDWEST. THE LEAD FRONT IS EXPECTED TO MOVE INTO THE  
GULF OF MEXICO AND WRN ATLANTIC BY NEXT MIDWEEK...BUT LAGGING MAIN  
LOW AND LEAD TRIPLE POINT COASTAL LOW PROXIMITY WOULD ALLOW  
WINTERY CONDITIONS TO LINGER OVER THE NORTHEAST.  
 
MEANWHILE UPSTREAM...THERE IS INCREASED MODEL SPREAD AND  
UNCERTAINTY WITH EVOLUTION OF AN AMPLIFIED MID-UPPER LEVEL ERN  
PACIFIC TROUGH POSITION ALOFT AND COASTAL PROXIMITY NEXT  
WEEK...BUT THE OVERALL PATTERN SEEMS TO FAVOR AMPLITUDE WITH  
SURFACE LOW/FRONTAL SYSTEM AND ORGANIZED PRECIPITATION APPROACH  
TOWARD THE WEST COAST TUE-NEXT WED.  
 
SCHICHTEL  
 

 
 
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