375  
FXUS02 KWBC 020659  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
158 AM EST FRI MAR 2 2018  
 
VALID 12Z MON MAR 5 2018 - 12Z FRI MAR 9 2018  
   
..GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
THE MEDIUM RANGE PERIOD BEGINS ON MONDAY WITH RELATIVELY GOOD  
AGREEMENT ON THE SYNOPTIC SCALE WITH IMPROVEMENT IN MODEL  
AGREEMENT ON THE 00Z RUNS COMPARED TO THE 12Z RUNS FROM THURSDAY  
WITH RESPECT TO THE LARGE STORM SYSTEM OVER THE CENTRAL U.S. THE  
00Z ECMWF AND ITS ENSEMBLE MEAN CONTINUE TO FAVOR A MORE NORTHERLY  
TRACK OF THE SURFACE LOW ACROSS THE GREAT LAKES REGION, AND THE  
LATEST CMC IS ALSO ON BOARD WITH THE MORE NORTHERLY TRACK.  
HOWEVER, THE 00Z GFS AND GEFS MEAN TAKE THE LOW ACROSS THE OHIO  
VALLEY AND MID-ATLANTIC REGION. THERE IS ALSO A STRONG MODEL  
SIGNAL FOR A TRIPLE POINT LOW TO FORM NEAR SOUTHERN NEW ENGLAND BY  
WEDNESDAY NIGHT WITH THE POSSIBILITY OF THIS BECOMING A NOR'EASTER  
FOR NEW ENGLAND FOR NEXT THURSDAY.  
 
FOR THE WESTERN U.S., THERE IS LESS CONFIDENCE WITH THE EVENTUAL  
TRACK AND MAGNITUDE OF A SURFACE LOW AND RESULTANT COLD FRONT OVER  
THE EASTERN PACIFIC BY THE MIDDLE OF NEXT WEEK, WITH THE ECMWF TO  
THE WEST OF THE MODEL CONSENSUS AND THE GFS BEING THE MOST  
PROGRESSIVE SOLUTION. THE WPC STAYED FAIRLY CLOSE TO PREVIOUS  
CONTINUITY AND AN ENSEMBLE MEAN APPROACH WAS USED HERE.  
 
   
..OVERVIEW AND WEATHER HIGHLIGHTS/THREATS
 
 
A STRONG STORM SYSTEM IS FORECAST TO AFFECT MUCH OF THE  
NORTH-CENTRAL U.S. FOR THE BEGINNING OF NEXT WEEK, AND THIS IS  
EXPECTED TO RESULT IN SIGNIFICANT SNOW AND PERHAPS BLIZZARD  
CONDITIONS TO THE NORTHWEST OF THE SURFACE LOW TRACK ACROSS THE  
DAKOTAS AND INTO MINNESOTA AND WISCONSIN. TEMPERATURES WILL  
RETURN TO BELOW SEASONAL AVERAGES ON THE ORDER OF 10-20 DEGREES,  
BUT ABOVE AVERAGE AHEAD OF THE FRONT FROM THE DEEP SOUTH TO THE  
OHIO VALLEY. RAIN AND SOME THUNDERSTORMS ARE EXPECTED AHEAD OF  
THE FRONTAL BOUNDARY.  
 
ANOTHER SWATH OF SNOW IS POSSIBLE THROUGH THE NORTHEAST AS A NEW  
LOW PRESSURE MOVES NORTHEASTWARD BY THURSDAY JUST OFF THE COAST.  
TO THE WEST, AN UPPER LOW AND ASSOCIATED SURFACE FRONT WILL SLOWLY  
MOVE TOWARD THE OREGON COAST BUT ITS SPEED IS STILL IN QUESTION.  
AT LEAST SOME PRECIPITATION IS EXPECTED TO REACH THE COAST FROM  
NORTHERN CALIFORNIA NORTHWARD MIDWEEK.  
 
HAMRICK  
 

 
 
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