154  
FXUS02 KWBC 040646  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
145 AM EST MON FEB 04 2019  
 
VALID 12Z THU FEB 07 2019 - 12Z MON FEB 11 2019  
   
..OVERVIEW
 
 
UPPER RIDGING WILL DOMINATE THE AREA JUST WEST OF THE GULF OF  
ALASKA AS WELL AS ACROSS THE FLORIDA STRAITS. THIS WILL FAVOR  
RENEWED TROUGHING ALONG THE WEST COAST WITH A STORM TRACK  
NORTHEASTWARD THROUGH THE GREAT LAKES/ST. LAWRENCE VALLEY.  
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT AND PREFERENCES
 
 
12Z GFS/ECMWF AND THEIR ENSEMBLES HAVE FINALLY COME MUCH CLOSER  
TOGETHER IN THE THU/FRI PERIOD WITH RESPECT TO THE NORTHEASTERN  
PACIFIC SEPARATION AND THE SPEED OF EJECTION OF THE FOUR CORNERS  
TROUGH. THE ECMWF ENSEMBLES HAVE BEEN THE LEADER IN THIS FLOW  
PATTERN BUT THE GFS/GEFS WERE MUCH MORE IN LINE SO THAT A BLENDED  
SOLUTION OFFERED A GOOD STARTING POINT. THIS WILL TAKE A LEAD  
SYSTEM OUT THROUGH SOUTHERN ONTARIO FRIDAY AS ANOTHER TROUGH DROPS  
DOWN THE WEST COAST. CANADIAN HIGH PRESSURE WILL SLIDE  
SOUTHEASTWARD THIS WEEKEND INTO THE MID-ATLANTIC AS A WEAK SYSTEM  
ATTEMPTS TO LIFT INTO THE LAKES NEXT SUN/MON. TO THE SOUTH, THE  
UPPER RIDGE WILL KEEP THE SURFACE FRONT FROM SINKING MUCH PAST  
CENTRAL FLORIDA AND THEN RETURN THROUGH THE GULF COAST AS A WARM  
FRONT LATE IN THE PERIOD.  
 
WEATHER HIGHLIGHTS/HAZARDS...  
 
WELL ABOVE AVERAGE TEMPERATURES IN THE SOUTHEAST/EAST (WITH RECORD  
HIGHS POSSIBLE) THURSDAY WILL BE REPLACED BY NEARER TO THEN BELOW  
AVERAGE TEMPERATURES (ESPECIALLY NORTH OF ~I-70) AS THE COLD FRONT  
CLEARS THE EAST COAST. FROM MT TO THE UPPER MIDWEST TEMPERATURES  
WILL REMAIN WELL BELOW AVERAGE ON THE NORTH SIDE OF AN ARCTIC  
FRONT THAT WILL LINGER NEAR THE DIVIDE. THE REST OF THE WEST WILL  
MOSTLY SEE BELOW AVERAGE TEMPERATURES DUE TO THE PERSISTENT  
TROUGHING.  
 
A SWATH OF HEAVIER PRECIPITATION (MOSTLY RAIN BUT PERHAPS NORTHERN  
FRINGE SNOW) WILL SPREAD EAST OF THE PLAINS THROUGH THE OH/TN  
VALLEYS AND INTO THE NORTHERN MID-ATLANTIC/NORTHEAST ON THURSDAY.  
FRONTAL/WARM-SECTOR RAINS MAY BE LOCALLY HEAVY ON THURSDAY BUT  
TREND LIGHTER ON FRIDAY AS THE SYSTEM WEAKENS AND LOOSES SUPPORT.  
AS THE MAIN LOW PULLS AWAY, LAKE-EFFECT SNOW WILL RESUME AT LEAST  
FRIDAY INTO SATURDAY AHEAD OF THE SURFACE HIGH. MORE PRECIPITATION  
WILL SPREAD OUT OF THE PLAINS INTO THE MID-MS VALLEY VIA ANOTHER  
WEAK IMPULSE OUT OF THE ROCKIES AND TO THE NORTH OF THE GULF WARM  
FRONT.  
 
FRACASSO  
 
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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