770  
FXUS02 KWBC 272000  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
359 PM EDT WED MAR 27 2019  
 
VALID 12Z SAT MAR 30 2019 - 12Z WED APR 03 2019  
   
..OVERVIEW AND WEATHER HIGHLIGHTS/HAZARDS
 
 
UPPER RIDGING OVER WESTERN CANADA WILL REFOCUS INTO ALASKA TO  
FAVOR TROUGHING THROUGH CENTRAL/EASTERN CANADA AND THE UPPER  
MIDWEST/GREAT LAKES/NORTHEAST. A LEAD LOW PRESSURE SYSTEM WILL  
EXIT THROUGH THE EASTERN GREAT LAKES/ST. LAWRENCE VALLEY THIS  
WEEKEND AS THE TRAILING COLD FRONT TRAVERSES THE S-CENTRAL AND  
EASTERN U.S., LINGERING ACROSS FLORIDA AND THE GULF OF MEXICO.  
THIS SYSTEM MAY BRING A VARIETY OF WEATHER INCLUDING SOME WEEKEND  
SNOW FROM THE UPPER GREAT LAKES TO NORTHERN NEW ENGLAND AND  
MODERATE RAINFALL AND CONVECTION AHEAD OF AND ALONG THE FRONT.  
ABOVE AVERAGE TEMPERATURES PRECEDING THE FRONT WILL BE REPLACED BY  
COOLER THAN AVERAGE TEMPERATURES THAT WILL MODERATE OVER THE  
FOLLOWING FEW DAYS.  
 
A SERIES OF SOUTHERN STREAM PACIFIC SHORTWAVES WILL PROGRESS  
THROUGH THE WEST/SOUTHWEST THEN EASTWARD ACROSS THE U.S. SOUTHERN  
TIER. THIS MAY INVIGORATE GULF OF MEXICO FRONTAL WAVE GENESIS NEXT  
WEEK DEPENDING ON EXACT TIMING/STRENGTH OF THE FEATURE ALOFT AND  
OFFSHORE CONDITIONS. RAINFALL MAY BE ENHANCED OVER PARTS OF  
FLORIDA NORTHEASTWARD ALONG THE GA/SC/NC COAST, BUT COULD ALSO  
STAY JUST OFFSHORE. UPSTREAM, ANOTHER SYSTEM WILL PUSH INTO THE  
WEST COAST EARLY NEXT WEEK WHICH MAY RESULT IN A BIT COOLER  
TEMPERATURES AMID PERIODS OF MODERATE RAIN AND HEAVIER ELEVATION  
SNOWS FROM THE NORTHWEST TO THE NORTHERN ROCKIES THEN EVENTUALLY  
ONTO THE PLAINS.  
   
..GUIDANCE ASSESSMENT/PREFERENCES
 
 
THE LATEST 06Z GFS/00Z ECMWF AND 06Z GEFS/00Z ECMWF ENSEMBLE MEANS  
SEEM TO OFFER REASONABLY SIMILAR LARGER SCALE PATTERN EVOLUTIONS,  
BUT LESS THAN STELLAR CONSISTENCY WITH STREAM INTERACTIONS AND  
TIMING/STRENGTH OF A MULTITUDE OF SMALLER-SCALE SYSTEMS EMBEDDED  
WITHIN THE FLOW. PREFERRED A COMPOSITE BLEND TO MITIGATE THIS WITH  
A MAJORITY DETERMINISTIC BLEND TO START, TRANSITIONING TO NEARLY A  
50/50 DETERMINISTIC/ENSEMBLE BLEND NEXT WED. THIS OFFERED A GOOD  
STARTING POINT FOR THE EXITING SYSTEM THIS WEEKEND WHERE THE  
MODELS HAVE COME INTO BETTER AGREEMENT AS WELL AS OVER FL AND OFF  
THE SE COAST NEXT TUE/WED WHERE THE 06Z GFS WAS PREFERRED OVER THE  
00Z ECMWF (PERHAPS TOO FAR EAST) BUT CONFIDENCE REMAINED LOWER  
THAN AVERAGE THERE GIVEN MIXED ENSEMBLE TRENDS.  
 
FRACASSO/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  
 
HAZARDS:  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE PACIFIC NORTHWEST,  
MON, APR 1.  
- HEAVY RAIN ACROSS PORTIONS OF CALIFORNIA AND THE PACIFIC  
NORTHWEST, MON, APR 1.  
- HEAVY RAIN ACROSS PORTIONS OF THE MIDWEST, WED, APR 3.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE MISSOURI RIVER BASIN.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE  
MISSISSIPPI AND MISSOURI RIVER BASINS.  
- FLOODING LIKELY ACROSS PORTIONS OF THE MISSISSIPPI AND MISSOURI  
RIVER BASINS.  
 
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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