331  
FXUS02 KWBC 311605  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1104 AM EST THU JAN 31 2019  
 
VALID 12Z SUN FEB 03 2019 - 12Z THU FEB 07 2019  
 
...WARMED CENTRAL-EASTERN U.S. FLIPS BACK TO COLD AND OFFERS  
SEVERAL WINTER STORM THREATS...   
..COLD AND STORMY PATTERN FOR THE WEST
 
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
THE WPC MEDIUM RANGE PRODUCT SUITE HAS ACCORDINGLY BEEN DERIVED  
FROM A COMPOSITE OF THE 06 UTC GEFS MEAN AND 00 UTC ECMWF/ECMWF  
ENSEMBLE MEAN. THESE FORECASTS IN PARTICULAR NOW SEEM QUITE WELL  
CLUSTERED THROUGH MEDIUM RANGE TIME SCALES, BOLSTERING FORECAST  
CONFIDENCE DESPITE THE TRANSITIONAL NATURE OF THE FLOW. THIS  
SOLUTION IS ON THE MORE AMPLIFIED EDGE OF THE OVERALL SOLUTION  
ENVELOPE FOR NEXT WEEK, REFLECTING A PRONOUNCED RECENT MODEL AND  
ENSEMBLE TREND. THIS TREND TO A LESSER EXTENT IS ALSO EVIDENT IN  
THE GFS, FV3, CANADIAN AND UKMET. WPC CONTINUITY HAS BEEN ADJUSTED  
TO REFLECT THIS SIGNIFICANT GUIDANCE TREND.  
   
..WEATHER HIGHLIGHTS/HAZARDS
 
 
A MUCH MILDER WEATHER PATTERN WILL BE PREVALENT ACROSS A MAJORITY  
OF THE CENTRAL AND EASTERN U.S. BY THIS WEEKEND AS FLOW FROM THE  
GULF OF MEXICO ADVECTS HIGHER HUMIDITY OVER THE REGION. A COUPLE  
OF WELL DEFINED LOW PRESSURE SYSTEMS ARE EXPECTED TO TRACK ACROSS  
THE PLAINS AND MIDWEST/GREAT LAKES BEFORE LIFTING INTO EASTERN  
CANADA OVER THE MEDIUM RANGE PERIOD, WITH THE POTENTIAL FOR  
SIGNIFICANT SNOW AND WINDS TO THE NORTH OF THE MAIN SURFACE LOWS  
ACROSS THE NORTHERN ROCKIES/PLAINS AND UPPER MIDWEST/GREAT LAKES  
AS ARCTIC AIRMASSES SETTLE SOUTHWARD WITH AND IN THE WAKE OF THESE  
DEEPENED LOW DOWN THROUGH THE CENTRAL THEN EAST-CENTRAL U.S. WITH  
LATER PERIOD FRONTAL PROGRESSION INTO THE EAST SLOWED BY A  
BUILDING MEAN RIDGE ALOFT. SHOWERS AND STORMS ARE ALSO LIKELY TO  
DEVELOP FROM THE GULF COAST TO THE MIDWEST AND EASTERN STATE IN  
THE WARM SECTORS OF THE MAIN SURFACE LOWS. SOME OF THIS RAINFALL  
HAVE A RISK TO BECOME LOCALLY HEAVY.  
 
MEANWHILE OUT WEST...THE GUIDANCE TREND TOWARD DEVELOPMENT OF A  
MUCH MORE AMPLIFIED MEAN MID-UPPER LEVEL TROUGH NEXT WEEK IS  
COMPLICATED BY CHANGING SHORTWAVE TROUGH SYSTEMS TO DIG/REINFORCE  
THE MAIN LONGER WAVE FEATURE. THAT SAID, FORECAST CONFIDENCE IS  
ABOVE AVERAGE IN THE OVERALL IDEA THAT MUCH OF THE WEST WILL  
BECOME INCREASINGLY COLD AND STORMY NEXT WEEK WITH PASSAGE OF  
MULTIPLE SYSTEMS/HEIGHT FALLS. THE WINTERY THREAT WILL INCLUDE  
HEAVY RAIN AND MOUNTAIN SNOW FOR MUCH OF CALIFORNIA AND FOR  
TERRAIN OF THE INTERMOUNTAIN WEST AND RCOKIES AS A STRONG PACIFIC  
DISTURBANCES MOVES INLAND.  
 
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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