271  
FXUS02 KWBC 260701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
200 AM EST FRI JAN 26 2018  
 
VALID 12Z MON JAN 29 2018 - 12Z FRI FEB 02 2018  
   
..GUIDANCE AND PREDICTABILTY ASSESSMENT
 
 
THE 18/00 UTC GFS AND 12/00 UTC ECMWF ARE WELL POSITIONED WITHIN  
THE OVERALL FORECAST DISTRIBUTION OUTLINED BY THEIR ENSEMBLES IN A  
MEDIUM RANGE FORECAST PATTERN WITH SLIGHTLY BETTER THAN AVERAGE  
FORECAST SPREAD AND IMPLIED PREDICTABILITY. A FAVORED COMPOSITE  
BLEND SEEMS TO OFFER A REASONABLE DEPICTION OF THE FLOW DESPITE  
UNRESOLVED SMALLER SCALE TIMING AND AMPLITUDE DIFFERENCES IN  
GENERALLY PROGRESSIVE FLOW THAT MAY GRADUALLY DEAMPLIFY NEXT WEEK.  
THIS SCENARIO MAINTAINS GOOD WPC DETERMINISTIC AND PROBABILISTIC  
CONTINUITY OVERALL.  
   
..PATTERN OVERVIEW AND WEATHER HIGHLIGHTS/THREATS
 
 
AMPLIFIED MID-UPPER LEVEL TROUGHING OVER THE HALF OF THE NATION  
MONDAY STEADILY WORKS OFFSHORE INTO THE WRN ATLANTIC TUE/WED. THIS  
WOULD USHER IN ANOTHER COLD SURGE DUG DOWN ACROSS THE CENTRAL AND  
ERN US AND ACT TO ENHANCE GREAT LAKE SNOWS IN THE WAKE OF LEAD  
WAVY FRONTAL SYSTEM PASSAGE. THE WPC COMPOSITE SOLUTION OFFERS A  
MODEST LEAD COASTAL LOW AND SEABOARD WEATHER THREAT...ALBEIT WITH  
SOME POTENTIAL FOR MORE ORGANIZED DEVELOPMENT AS PER SOME ENSEMBLE  
MEMBERS THAT WOULD INCREASE THE SNOW THREAT FROM THE ERN  
MID-ATLANTIC INTO NEW ENGLAND.  
 
PACIFIC HEIGHT FALLS AND SYSTEM APPROACH WILL INCREASE POTENTIAL  
FOR HEAVIER PCPN AND TERRAIN ENHANCED RAINS AND ELEVATION SNOWS  
EARLY WEEK AND AGAIN LATER WEEK WITH ADDITIONAL SYSTEM APPROACH  
AND INLAND PROGRESSION IS LESS AMPLIFIED/MORE UNCERTAIN FLOW.  
 
IN BETWEEN...A WARMING/STABLE MID-UPPER LEVEL RIDGE IS SLATED TO  
PROGRESS FROM THE WRN US MON EASTWARD TO THE ERN SEABOARD BY THU  
AND PROVIDE ANOTHER TASTE OF SPRING AS LEAD LOWER ATMOSPHERIC WARM  
AIR ADVECTION AND AN INCREASING RETURN FLOW OF GULF OF MEXICO  
MOISTURE WOULD BE AVAILABLE TO FUELS AN EMERGING EAST-CENTRAL US  
PRECIPITATION PATTERN. THIS WOULD INCLUDE POTENTIAL FOR SOME  
HEAVIER CONVECTION OVER MID-SRN LATITUDES AND SNOWS OVER THE NRN  
TIER.  
 
SCHICHTEL  
 

 
 
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