068  
FXUS02 KWBC 210700  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
200 AM EST THU FEB 21 2019  
 
VALID 12Z SUN FEB 24 2019 - 12Z THU FEB 28 2019  
 
...MAJOR UPPER MIDWEST/GREAT LAKES/INTERIOR NEW ENGLAND WINTER  
STORM SUNDAY/MONDAY...  
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT AND PREFERENCES
 
 
GUIDANCE WAS REASONABLY WELL-CLUSTERED AT MID-LARGER SCALES  
THROUGH THE MEDIUM RANGE PERIOD AND A COMPOSITE BLEND OF THE  
LATEST ECMWF/UKMET/CANADIAN AND ECMWF ENSEMBLES OFFERS A  
REASONABLE STARTING POINT FOR THE FORECAST. THE GFS AND GEFS ARE  
LESS ROBUST TO BRING LOWER LEVEL COLDER AIR SOUTHWARD NEXT WEEK  
AND THEIR SOLUTIONS WERE DOWNPLAYED AS THE FV3 SHOWED AN OPPOSITE  
TREND MORE IN LINE WITH THE OTHER GUIDANCE.  
 
   
..WEATHER HIGHLIGHTS/HAZARDS
 
 
A THREAT FOR SIGNIFICANT SNOWS/SOME ICING EXISTS AROUND A DEEP  
SURFACE LOW. THE RAPIDLY DEEPENING SYSTEM (CENTRAL PRESSURE FALL  
OF ABOUT 20MB/24 HRS BETWEEN SAT AND SUN MORNING) LIFTS INTO THE  
GREAT LAKES AND THEN EXITS OUT THE ST. LAWRENCE VALLEY SUNDAY INTO  
MONDAY. THIS SYSTEM HAS THE POTENTIAL TO DEEPEN INTO THE UPPER  
970S MB OR AT LEAST LOW 980S MB WHICH MAY BE CLOSE TO MONTHLY  
RECORD LOW PRESSURE VALUES FOR PORTIONS OF LOWER MICHIGAN SUNDAY.  
EXPECT STRONG/GUSTY WINDS AND POTENTIAL BLIZZARD CONDITIONS OVER  
THE UPPER MIDWEST/GREAT LAKES AND INTO CANADA SUNDAY-MONDAY. MILD  
AIR WILL SURGE NORTHWARD EAST OF A TRAILING COLD FRONT WITH A  
BRIEF SPIKE IN TEMPS TO THE 60/70S AS FAR NORTH AS THE  
MID-ATLANTIC. FARTHER SOUTH, A PROLONGED HEAVY RAIN PATTERN WILL  
FINALLY END WITH COLD FRONTAL PASSAGE, WITH LEAD RECORD WARM TEMPS  
POSSIBLE OVER FLORIDA.  
 
A LONG-STANDING AND WINTRY MEAN UPPER TROUGH OVER THE WEST  
DEAMPLIFIES NEXT WEEK, BUT WILL STILL BE REINFORCED OVER THE  
NORTHWEST INTO SUN-MON AS ENERGY UNDERCUTS AND DIGS TO THE LEE OF  
A BLOCKING ALASKA-CENTERED CLOSING UPPER HIGH. THIS WILL BRING  
UNSETTLED WEATHER ACROSS THE NORTHWEST/NORTHERN CA AND THE  
NORTH-CENTRAL INTERMOUNTAIN WEST/ROCKIES. THE BEST CHANCE FOR  
HEAVY SNOW WILL BE FROM THE CASCADES TO ESPECIALLY NORTHERN CA  
WITH EMERGENCE OF UNCERTAIN PACIFIC FLOW UNDERCUTTING THE NORTHERN  
STREAM.  
 
FLATTER FLOW DOWNSTREAM OVER CENTRAL AND EASTERN U.S. NEXT WEEK  
REDUCES POTENTIAL FOR BIG STORMS, BUT A SERIES OF SMALLER/LESS  
PREDICTABLE SYSTEMS WILL PROGRESS OVER THE REGION. THIS WILL STILL  
FAVOR COLD AIR SURGES/ANOMALOUSLY COLD TEMPS THROUGH THE N-CENTRAL  
U.S. AND SNOW SWATHS OVER THE NORTHERN TIER STATES. RAINFALL ALSO  
REDEVELOPS ACROSS THE GULF COAST/FL WITH THE FRONTS, BUT GUIDANCE  
HAS BACKED OFF WITH AMOUNTS.  
 
SCHICHTEL  
 
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION AND WINTER WEATHER OUTLOOK  
PROBABILITIES ARE FOUND 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  
 

 
 
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