883  
FXUS02 KWBC 160707  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
207 AM EST SAT FEB 16 2019  
 
VALID 12Z TUE FEB 19 2019 - 12Z SAT FEB 23 2019  
 
...MULTI-DAY THREATS OF HEAVY RAIN FOR THE LOWER  
MISSISSIPPI/TENNESSEE VALLEYS TO SOUTH-CENTRAL APPALACHIANS AND  
OHIO VALLEY/NORTHERN MID-ATLANTIC HEAVY SNOW/ICE...  
...WESTERN TO CENTRAL U.S. COLD/UNSETTLED WEATHER TO FOCUS INTO  
THE SOUTHWEST...  
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT AND WEATHER HAZARDS
 
 
MODELS AND ENSEMBLES MAINTAIN A PATTERN WITH A SERIES OF POTENT  
UPPER TROUGHS/HEIGHT FALLS PROGRESSING OVERTOP A NORTHEAST PACIFIC  
RIDGE THAT THEN DIG SHARPLY SOUTHWARD TO REINFORCE A WESTERN US  
MEAN TROUGH. THE SUPPORTS WESTERN TO CENTRAL U.S. COLD AND  
UNSETTLED WEATHER WITH A FOCUS OVER THE SOUTHWEST. LEAD DEEP  
LAYERED AND ANOMALOUSLY MOIST SOUTHWEST FLOW CHANNELED FROM THE  
SOUTHERN PLAINS TO THE EAST MEANWHILE ACTS TO SUSTAIN A SOUTHEAST  
RIDGE AND FUEL MULTI-DAY THREATS OF HEAVY RAIN/TRAINING FROM THE  
LOWER MISSISSIPPI/TENNESSEE VALLEYS TO SOUTH-CENTRAL APPALACHIANS  
AND OHIO VALLEY/NORTHERN MID-ATLANTIC HEAVY SNOW/ICE. THIS OCCURS  
AS MULTIPLE WAVES TRAVERSE AND MOISTURE FEEDS INTO A LINGERING  
SOUTHERN TO EASTERN U.S. SURFACE FRONT AND INTO COLD SURFACE HIGH  
PRESSURE SETTLED/DAMMED OVERTOP.  
 
IN THIS PATTERN MAIN MID-UPPER LEVEL TROUGHS EJECT FROM THE  
SOUTHWEST TO NORTHEAST TUE-THU AS A MAIN UPSTREAM TROUGH DIGS FROM  
THE PACIFIC NORTHWEST TO THE SOUTHWEST WED-SAT. THIS AMPLIFIED  
PATTERN OVERALL OFFERS ABOVE NORMAL FORECAST PREDICTABILITY NEXT  
WEEK, ALBEIT WITH TIMING/STRENGTH VARIANCE WITH EMBEDDED SMALL-MID  
SCALE SYSTEMS GROWING GRADUALLY OVER TIME. THE WPC MEDIUM RANGE  
PRODUCT SUITE WAS PRIMARILY DERIVED FROM A COMPOSITE BLEND OF WELL  
CLUSTERED GUIDANCE FROM THE RECENT GFS/ECMWF AND GEFS/ECMWF  
ENSEMBLE MEANS ALONG WITH THE NATIONAL BLEND OF MODELS AND WPC  
CONTINUITY.  
 
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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