191  
FXUS02 KWBC 282053  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
353 PM EST THU FEB 28 2019  
 
VALID 12Z SUN MAR 03 2019 - 12Z THU MAR 07 2019  
 
...LOW PRESSURE SYSTEM LIKELY TO BRING THREAT OF HEAVY SNOW/ICE  
FROM PORTIONS OF THE MID-MISSISSIPPI/OHIO VALLEYS TO THE  
MID-ATLANTIC AND NORTHEAST SUN-MON...  
 
   
..PATTERN OVERVIEW
 
 
THE FORECAST OF LARGE SCALE FLOW HAS MAINTAINED GOOD CONTINUITY  
OVER THE PAST DAY. DOWNSTREAM FROM PERSISTENT MEAN  
RIDGING/POSITIVE HEIGHT ANOMALIES OVER NORTHWESTERN NORTH AMERICA,  
A TROUGH WILL AMPLIFY INTO THE EASTERN U.S. WITH GREATEST DEPTH  
AROUND MIDWEEK BEFORE THE TROUGH AXIS CONTINUES INTO THE WESTERN  
ATLANTIC. AT THE SAME TIME A MEAN RIDGE WILL BUILD INTO THE  
WEST-CENTRAL U.S. AS A MEAN TROUGH SETTLES NEAR THE WEST COAST.  
 
   
..GUIDANCE EVALUATION/PREFERENCES
 
 
AGREEMENT AMONG MODELS/ENSEMBLES HAS IMPROVED SIGNIFICANTLY OVER  
THE PAST 24 HOURS WITH RESPECT TO MANY OF THE FORECAST DETAILS  
DURING THE MEDIUM RANGE. A BLEND OF THE LATEST DETERMINISTIC  
SOLUTIONS (ECMWF/GFS/CMC/UKMET) WAS USED AS A STARTING POINT FOR  
THE FORECAST DURING DAYS 3-5 (SUN-TUE). SOLUTIONS ARE NOW  
RELATIVELY WELL CLUSTERED AROUND THE ENSEMBLE MEANS WITH THE WAVE  
OF LOW PRESSURE EXPECTED TO MOVE FROM THE LOWER MISSISSIPPI VALLEY  
TO OFF THE NEW ENGLAND COAST SUN-MON, WITH CONFIDENCE INCREASING  
IN THE POTENTIAL FOR SIGNIFICANT WINTER WEATHER NORTH/WEST OF THE  
LOW TRACK. FARTHER WEST, MODELS ALSO SHOW IMPROVED CONSENSUS WITH  
RESPECT TO AN ENERGETIC SHORTWAVE/LOW PRESSURE SYSTEM EXPECTED TO  
REACH THE WEST COAST TUE NIGHT INTO WED. SOLUTIONS SHOW SPREAD ON  
BOTH TIMING AND AMPLITUDE OF THIS FEATURE, HOWEVER THE ENSEMBLE  
MEANS ARE REASONABLY WELL-CENTERED WITHIN THE SPREAD. THIS MAKES  
THE MEANS SUITABLE TO COMPRISE A SIGNIFICANT COMPONENT OF THE  
FORECAST FOR DAYS 6-7 (WED-THU). OVERALL, THE FORECAST REMAINED  
CLOSE TO CONTINUITY WITH ONLY MINOR ADJUSTMENTS.  
 
   
..WEATHER HIGHLIGHTS/HAZARDS
 
 
A BROAD AREA OF PRECIPITATION WILL ACCOMPANY THE VIGOROUS WAVE  
TRACKING NORTHEAST OVER PARTS OF THE EASTERN STATES AND INTO THE  
CANADIAN MARITIMES SUN-MON. NORTHWEST TRENDS IN THE PAST DAY HAVE  
PUSHED THE MOST LIKELY AREA FOR SIGNIFICANT WINTRY WEATHER TO AN  
AXIS EXTENDING FROM THE MID-MISSISSIPPI VALLEY/OHIO VALLEY INTO  
PORTIONS OF THE MID-ATLANTIC AND NORTHEAST. AT THIS TIME, THE  
SPECIFICS REMAIN A BIT MURKY WITH RESPECT TO P-TYPE IN THE MAJOR  
CITIES ALONG THE EAST COAST, BUT THE GREATEST POTENTIAL FOR HEAVY  
SNOWS SHOULD BE ACROSS INTERIOR AREAS FROM OHIO/PENNSYLVANIA TO  
INTERIOR NEW ENGLAND. A MORE CONSISTENT THEME FROM YESTERDAY IS  
THE POTENTIAL FOR HEAVY RAINFALL OVER PARTS OF THE LOWER  
MISSISSIPPI VALLEY AND TENNESSEE VALLEY/INTERIOR SOUTHEAST.  
 
RAIN AND HIGHER ELEVATION SNOW IN PROGRESS OVER THE  
CENTRAL/SOUTH-CENTRAL PARTS OF THE WEST LATE IN THE WEEKEND WILL  
TAPER OFF FROM WEST TO EAST. THEN FROM TUE ONWARD THE NEXT SYSTEM  
IN THE SERIES WILL SPREAD A BROAD AREA OF MOISTURE ACROSS THE  
WEST, WITH GREATER NORTHWARD EXTENT THAN WITH THE PREVIOUS SYSTEM.  
FAVORED TERRAIN OVER NORTHERN AND CENTRAL CALIFORNIA SHOULD ONCE  
AGAIN SEE THE HIGHEST PRECIPITATION TOTALS WITH THIS SYSTEM.  
MOISTURE REACHING NORTHERN PORTIONS OF THE WEST MAY BRING WINTRY  
WEATHER TO LOW ELEVATIONS OVER SOME AREAS GIVEN THE COLD  
TEMPERATURES IN PLACE FROM EARLY IN THE WEEK.  
 
CONTINUE TO EXPECT COLDEST TEMPERATURES RELATIVE TO NORMAL DURING  
SUN-MON WITH SOME CENTRAL U.S. LOCATIONS SEEING ANOMALIES OF  
30-45F BELOW NORMAL AND A WIDESPREAD AREA OVER THE PLAINS/MIDWEST  
WITH READINGS THAT WILL APPROACH OR BREAK DAILY RECORDS--MORE  
LIKELY A GREATER NUMBER FOR COLD HIGHS. INTERIOR NORTHWEST  
LOCATIONS MAY ALSO SEE SOME TEMPERATURES AT LEAST 20F BELOW NORMAL  
WITH LOCAL CHALLENGES TO DAILY RECORDS. THE AREA OF POTENTIAL  
DAILY RECORDS WILL LIKELY SHIFT MORE INTO THE EASTERN HALF OF THE  
COUNTRY (MIDWEST/GREAT LAKES/OHIO VALLEY) BY TUE.  
 
RYAN/RAUSCH  
 
HAZARDS:  
- HEAVY RAIN ACROSS PORTIONS OF CALIFORNIA, THE CENTRAL GREAT  
BASIN, THE PACIFIC NORTHWEST, AND THE SOUTHWEST, TUE-WED, MAR  
5-MAR 6.  
- HEAVY RAIN ACROSS PORTIONS OF THE MID-ATLANTIC, THE NORTHEAST,  
THE TENNESSEE VALLEY, THE LOWER MISSISSIPPI VALLEY, THE SOUTHERN  
APPALACHIANS, THE SOUTHEAST, AND THE OHIO VALLEY, SUN-MON, MAR  
3-MAR 4.  
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL GREAT BASIN, THE  
NORTHERN PLAINS, THE NORTHERN ROCKIES, THE CENTRAL ROCKIES,  
CALIFORNIA, THE NORTHERN GREAT BASIN, THE PACIFIC NORTHWEST, AND  
THE SOUTHWEST, WED-THU, MAR 6-MAR 7.  
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL ROCKIES, THE  
NORTHEAST, THE CENTRAL GREAT BASIN, THE SOUTHERN ROCKIES, THE  
MIDDLE MISSISSIPPI VALLEY, THE MID-ATLANTIC, THE SOUTHERN  
APPALACHIANS, THE CENTRAL APPALACHIANS, THE GREAT LAKES, THE OHIO  
VALLEY, AND THE SOUTHWEST, SUN-MON, MAR 3-MAR 4.  
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL ROCKIES, THU, MAR 7.  
- SEVERE WEATHER ACROSS PORTIONS OF THE SOUTHEAST, THE LOWER  
MISSISSIPPI VALLEY, THE SOUTHERN APPALACHIANS, AND THE TENNESSEE  
VALLEY, SUN, MAR 3.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE MID-ATLANTIC.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE LOWER  
MISSISSIPPI VALLEY, THE TENNESSEE VALLEY, THE GREAT LAKES, THE  
MIDDLE MISSISSIPPI VALLEY, THE MID-ATLANTIC, CALIFORNIA, THE UPPER  
MISSISSIPPI VALLEY, THE SOUTHEAST, THE PACIFIC NORTHWEST, AND THE  
OHIO VALLEY.  
- FLOODING LIKELY ACROSS PORTIONS OF THE SOUTHEAST.  
- MUCH BELOW NORMAL TEMPERATURES FOR MUCH OF THE EASTERN  
TWO-THIRDS OF THE COUNTRY, INCLUDING THE INTERIOR SECTIONS OF THE  
PACIFIC NORTHWEST, SUN-THU, MAR 3-MAR 7.  
 
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