414  
FXUS02 KWBC 220717  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
316 AM EDT FRI MAR 22 2019  
 
VALID 12Z MON MAR 25 2019 - 12Z FRI MAR 29 2019  
   
..GUIDANCE ASSESSMENT/PREFERENCES
 
 
LATEST MODELS AND ENSEMBLES SEEM COMPATABLE MON/TUE AND PREFER A  
COMPOSITE SOLUTION TO SMOOTH THE LESS PREDICTABLE SMALLER SCALE  
FEATURES. WHILE GUIDANCE OVERALL OFFERS A FAIRLY SIMILAR LARGER  
SCALE PATTERN EVOLUTION FOR THE NEXT WEEK, RUN-RUN VARIANCE WITH A  
MULTITUDE OF SMALLER EMBEDDED SYSTEMS AND STREAM INTERACTIONS  
GROWS QUICKLY. ACCORDINGLY, IT SEEMED MORE PRUDENT TO FAVOR AN  
ENSEMBLE MEAN FORECAST APPROACH DAYS 5-7 AND THE WPC MEDIUM RANGE  
PRODUCT SUITE WAS PRIMARILY DERIVED FROM A BLEND OF LATEST  
GEFS/ECMWF ENSEMBLES.  
   
..WEATHER HIGHLIGHTS AND HAZARDS
 
 
THIS MEDIUM RANGE PERIOD STARTS MONDAY/TUESDAY AS A SOUTHERN  
STREAM FRONT WITH SEVERAL MOISTURE/ENHANCED PRECIPITATION FOCUSING  
WAVES EJECTS ACROSS THE SOUTH/SOUTHEAST/AND MID-ATLANTIC. THESE  
WAVES CUT UNDERNEATH/INTERACT WITH A COOLING NORTHERN STREAM  
FRONTAL DRAPE WHOSE POST-FRONTAL HIGH PRESSURE BUILDS DOWN THROUGH  
THE CENTRAL AND EASTERN U.S.  
 
MEANWHILE, A PROTRACTED SERIES OF PACIFIC SYSTEMS WITH ASSOCIATED  
HEIGHT FALLS AND ENHANCED PRECIPITATION SWATHS WILL TRACK ONSHORE  
AND ACROSS MUCH OF THE WEST EARLY THROUGH MID NEXT WEEK IN ADVANCE  
OF AN MEAN CLOSED LOW/TROUGH REINFORCED JUST OFF WEST COAST.  
EXPECT HEAVIEST PRECIPITATION/HEAVY MOUNTAIN SNOWS THREATS FROM  
NORTHERN CALIFORNIA/OREGON TO THE NORTHERN ROCKIES. INDICATION  
THAT THE BULK OF PACIFIC TROUGH ENERGY WILL EJECT THROUGH THE WEST  
WED/THU TO EMERGE OVER THE PLAINS LATER NEXT WEEK TO INDUCE  
CYCLO/FRONTOGENESIS. THIS MAY OCCUR JUST AS A RENEWED NORTHERN  
STREAM MAY FORCE COOL AIR DOWN INTO THE UNSETTLED N-CENTRAL  
STATES. THIS AIRMASS WOULD PROVE TO BE IN STARK CONTRAST TO A  
RAPIDLY WARMING AIRMASS SPREADING OVER THE E-CENTRAL U.S. WHERE  
MOIST GULF RETURN FLOW MAY FUEL AN EXPANDING RISK OF ENHANCING  
RAINS/CONVECTION CHANNELING BETWEEN THE SURGING FRONTS AND  
RETREATING EASTERN U.S. HIGH PRESSURE.  
 
SCHICHTEL  
 
ADDITIONAL 3-7 DAY HAZARDS INFORMATION CAN BE FOUND ON THE WPC  
MEDIUM RANGE HAZARDS CHART AT:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, WINTER WEATHER OUTLOOK PROBABILITIES  
AND HEAT INDICES ARE 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  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML  
 

 
 
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