380  
FXUS02 KWBC 230413  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1212 AM EDT SAT MAR 23 2019  
 
VALID 12Z TUE MAR 26 2019 - 12Z SAT MAR 30 2019  
   
..GUIDANCE ASSESSMENT/PREFERENCES
 
 
MODELS AND ENSEMBLES SEEM REASONABLY COMPATABLE INTO DAYS  
3-4/TUE-WED AND A FAVORED COMPOSITE SOLUTION DE-EMPHASIZES THE  
LESS PREDICTABLE SMALLER SCALE FEATURES. WHILE GUIDANCE OVERALL  
CONTINUES TO OFFERS A FAIRLY SIMILAR LARGER SCALE CONUS AND  
VICINITY PATTERN EVOLUTION OVER FOR MUCH OF NEXT WEEK, RUN-RUN  
VARIANCE WITH A MULTITUDE OF MID-SMALLER SCALE EMBEDDED SYSTEMS  
AND STREAM INTERACTIONS DO GROW QUICKLY WITH TIME. THIS IS  
ESPECIALLY EVIDENT WITH RECENT GFS AND TO A LESSER EXTENT FV3 RUNS  
THAT DO NOT CLUSTER AS WELL WITH LATEST GEFS/ECMWF ENSEMBLES AS  
THE ECMWF. VARIANCE SEEMS TO MAINLY STEM FROM DIFFERENCES IN THE  
HANDLING OF EAST-PACIFIC TROUGH ENERGIES. PREFER TO MAINTAIN WPC  
AND GUIDANCE CONTINUITY BETTER WITH A 18 UTC GEFS MEAN AND 12 UTC  
ECMWF/ECMWF ENSEMBLE MEAN BLENDED FORECAST APPROACH DAY 5-7.  
   
..WEATHER HIGHLIGHTS AND HAZARDS
 
 
A SOUTHERN STREAM FRONT WITH MOISTURE AND ENHANCED PRECIPITATION  
FOCUSING WAVES EJECTS ACROSS THE SOUTHEAST INTO TUESDAY. THE  
FRONTAL LOW/COASTAL WAVE WILL CUT UNDERNEATH AND INTERACT WITH A  
COOLING NORTHERN STREAM FRONTAL DRAPE OVERTOP WHOSE DEEPENED  
POST-FRONTAL HIGH PRESSURE THEN SETTLES DOWN THROUGH THE CENTRAL  
AND EASTERN U.S. MEANWHILE, A PROTRACTED SERIES OF PACIFIC SYSTEMS  
WITH ASSOCIATED HEIGHT FALLS AND ENHANCED PRECIPITATION SWATHS ARE  
SLATED TO TRACK ONSHORE AND ACROSS MUCH OF THE WEST THROUGH NEXT  
MIDWEEK AHEAD OF AN MEAN CLOSED LOW/TROUGH REINFORCED JUST OFF  
WEST COAST. HEAVIEST PRECIPITATION/HEAVY MOUNTAIN SNOWS THREATEN  
NORTHERN CALIFORNIA/OREGON THROUGH THE NORTHERN ROCKIES. IT IS  
EXPECTED THAT THE BULK OF PACIFIC TROUGH ENERGY WILL EJECT THROUGH  
THE WEST WED/THU TO EMERGE OVER THE PLAINS INTO 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 FROM THE EAST-CENTRAL U.S.  
TO EASTERN U.S. INTO NEXT WEEKEND. DEEPENING RETURN FLOW FROM THE  
GULF OF MEXICO WOULD FUEL AN EXPANDING RISK OF ENHANCING  
RAINS/CONVECTION TO CHANNEL BETWEEN THE APPROACHING FRONTS AND  
SLOWLY RETREATING EASTERN U.S. HIGH PRESSURE. THE EMERGING HEAVY  
RAIN AREA THREATENS AREAS OF THE MISSISSIPPI VALLEY/MIDWEST (WHERE  
FLOODING IS ONGOING) HEADING INTO NEXT WEEKEND. UNCERTAINTY  
REMAINS REGARDING HEAVIEST RAINFALL AMOUNTS/PLACEMENT, BUT THE  
GUIDANCE SIGNAL FOR DEVELOPENT CONTINUES TO GROW.  
 
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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