679  
FXUS02 KWBC 261558  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1157 AM EDT TUE MAR 26 2019  
 
VALID 12Z FRI MAR 29 2019 - 12Z TUE APR 02 2019  
   
..OVERVIEW AND WEATHER HIGHLIGHTS AND HAZARDS
 
 
STRONG UPPER RIDGING INITIALLY OVER BRITISH COLUMBIA WILL DRIFT  
NORTHWESTWARD INTO ALASKA WHICH FAVORS BROAD TROUGHING THROUGH  
CENTRAL/EASTERN CANADA AND THROUGH THE UPPER MIDWEST/GREAT  
LAKES/NORTHEAST. UNDERNEATH THE WESTERN CANADIAN HIGH, WEAKER  
SHORTWAVES WILL DROP THROUGH THE FOUR CORNERS REGION AND  
EVENTUALLY TURN THE CORNER ACROSS TEXAS EARLY NEXT WEEK AND HEAD  
EASTWARD, POSSIBLY INVIGORATING A SURFACE BOUNDARY IN THE GULF. IN  
THE NORTHERN STREAM, LOW PRESSURE WILL EXIT THROUGH THE EASTERN  
GREAT LAKES/ST. LAWRENCE VALLEY THIS WEEKEND AS THE TAIL-END OF  
ITS COLD FRONT LINGERS ACROSS FLORIDA. THIS SYSTEM WILL BRING A  
VARIETY OF WEATHER TO THE CENTRAL/EASTERN STATES FRI-SUN: SEVERE  
WEATHER FOR PORTIONS OF OKLAHOMA ON FRIDAY (SEE SPC FOR MORE  
INFO), WELL ABOVE AVERAGE TEMPERATURES TO THE  
NORTHEAST/MID-ATLANTIC SATURDAY, WELL BELOW AVERAGE TEMPERATURES  
BEHIND THE FRONT (ESPECIALLY OVER THE SOUTHERN PLAINS INTO THE  
MIDWEST ON SUNDAY), SNOW ACROSS THE CENTRAL PLAINS FRI/SAT, AND  
LOCALLY HEAVY RAINFALL AHEAD OF AND ALONG THE FRONT INITIALLY IN  
THE MIDWEST TO NORTHEAST BUT THEN PERHAPS OVER FLORIDA NEXT WEEK.  
THE WEST WILL SEE ANOTHER SYSTEM PUSH INTO WA/OR EARLY NEXT WEEK  
WITH ONLY LIGHT TO MODEST AMOUNTS OF RAIN/SNOW.  
 
   
..GUIDANCE ASSESSMENT/PREFERENCES
 
 
LATEST DETERMINISTIC MODELS WERE REASONABLY WELL-CLUSTERED FOR THE  
FRI-SUN PERIOD AS THE EASTERN SYSTEM LIFTS INTO SOUTHEASTERN  
CANADA AND THE WESTERN SHORTWAVES DIP INTO THE SOUTHERN ROCKIES.  
THE 06Z GFS AND 00Z UKMET BECAME QUICKER/FLATTER THAN THE 00Z  
GFS/ECMWF/CANADIAN LATE SAT INTO SUN OVER THE FOUR CORNERS BUT  
WEIGHTED THE SLOWER SOLUTIONS MORE THAN THE QUICKER ONES BY ABOUT  
A 3:1 RATIO GIVEN THE GOOD ENSEMBLE CLUSTERING BUT STILL UNCERTAIN  
EVOLUTION PRIOR. EXODUS OF THE EASTERN SYSTEM WAS UNCERTAIN OVER  
NEW ENGLAND LATE SUN/EARLY MON AS THE GFS/CANADIAN RUNS WERE  
QUICKER THAN THE ECMWF/UKMET WITH A POSSIBLE WAVE ALONG THE FRONT.  
FOR NOW, OPTED TO KEEP THE FRONT MORE PROGRESSIVE GIVEN THE  
PROPENSITY OF THE ECMWF TO BE TOO SLOW, BUT MANY ENSEMBLE MEMBERS  
SHOWED SUCH DEVELOPMENT. TRENDED TOWARD MORE ENSEMBLE WEIGHTING BY  
NEXT MON/TUE WITH DETAILS ADDED PER THE ECMWF/CANADIAN OFF THE  
WEST COAST WITH AN INCOMING SYSTEM THAT THE GFS RUNS HAVE LOST IN  
RECENT RUNS. ENSEMBLE MEMBERS STRONGLY SHOW A COHERENT LOW  
PRESSURE (ALBEIT ONLY OF MODEST DEPTH) MOVING TOWARD THE  
WASHINGTON COAST AROUND NEXT TUESDAY WITH THE FRONT INLAND INTO  
THE GREAT BASIN AND CENTRAL CALIFORNIA.  
 
FRACASSO  
 
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  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page