455  
FXUS02 KWBC 112009  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
408 PM EDT THU APR 11 2019  
 
VALID 12Z SUN APR 14 2019 - 12Z THU APR 18 2019  
 
...TWO MAJOR SPRING STORMS OFFER A HEAVY RAINFALL/FLOODING THREAT  
FROM THE MID-LOWER MISSISSIPPI VALLEY TO THE OHIO VALLEY THIS  
WEEKEND AND AGAIN THROUGH NEXT MIDWEEK ALONG WITH A RISK OF SEVERE  
WEATHER OVER THE SOUTH...  
 
...WEATHER HIGHLIGHTS/HAZARDS AND GUIDANCE/PREDICTABILITY  
ASSESSMENT...  
 
A HIGHLY DYNAMIC MID-UPPER TROUGH/HEIGHT FALLS AND COUPLED UPPER  
JET SUPPORT ACROSS THE SOUTHERN PLAINS THROUGH THE MID-LOWER MS/OH  
VALLEYS THIS WEEKEND, BRINGING WIDESPREAD HEAVY RAINS WITH  
POTENTIAL OF EXCESSIVE RAINFALL AND FLASH FLOODING AS DEEP  
MOISTURE (1.5+ S.D. ABOVE NORMAL) IS PULLED INLAND FROM THE GULF  
OF MEXICO. THERE IS ALSO A RISK OF SEVERE WARM SECTOR CONVECTION  
OVER THE SOUTH AS PER SPC. THE POTENT LOW AND ENHANCED BUT  
PROGRESSIVE PRECIPITTAION WILL TRACK OVER THE NORTHEAST MONDAY  
WHERE THERE IS SOME THREAT OF ONSET NORTHERN NEW ENGLAND SNOW/ICE.  
THERE WILL ALSO BE RAINS/CONVECTION ALONG AND AHEAD OF A TRAILING  
COLD FRONT MOVING ACROSS THE SOUTH, EAST AND OFFSHORE INTO THE  
GULF OF MEXICO AND WESTERN ATLANTIC. THE 00 UTC  
GFS/ECMWF/GEFS/ECMWF ENSEMBLE MEAN SOLUTIONS ARE WELL CLUSTERED IN  
A PATTERN WITH ABOVE NORMAL PREDICTABILITY.  
 
MEANWHILE UPSTREAM, MODELS AND ENSEMBLES STILL AGREE TO BRING  
POTENT MID-UPPER LEVEL TROUGHING/AMPLE HEIGHT FALLS/FRONTAL  
PRECIPITATION INTO THE WEST COAST SUNDAY.  
THE SOUTHERN STREAM UPPER TROUGH IS REINFORCED OVER THE GREAT  
BASIN AND ROCKIES MONDAY/TUESDAY TO EMERGE OVER THE PLAINS MIDWEEK  
THEN EAST-CENTRAL U.S. BY THURSDAY. HEIGHT FALLS SHOULD INDUCE  
PLAINS CYCLOGENESIS WITH A RENEWED RETURN FLOW OF DEEPENING GULF  
MOISTURE AND ASCENT LEADING TO ENHANCED RAINFALL IN EASTERN OK/TX  
EXTENDING DOWNSTREAM INTO THE MID-LOWER MS TO OHIO VALLEYS. GIVEN  
A SIMILAR CYCLONE TRACK/INTENSITY AND SUPPORT PROFILE/UPPER LEVEL  
TROUGH TRACK, SIMILAR AREAS HIT BY RAIN THIS WEEKEND ARE EXPECTED  
TO RECEIVE A REPEAT HEAVY RAIN AND STRONG TO SEVERE THREAT. THE 00  
UTC GFS/ECMWF/GEFS/ECMWF ENSEMBLE MEAN SOLUTIONS ARE WELL  
CLUSTERED IN A PATTERN WITH MUCH ABOVE NORMAL PREDICTABILITY  
CONSIDERING THIS LONGER TIMEFRAME.  
 
SCHICHTEL  
 
HAZARDS:  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE PACIFIC NORTHWEST AND  
THE NORTHERN GREAT BASIN, SUN-TUE, APR 14-APR 16.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE PACIFIC NORTHWEST,  
THE NORTHERN ROCKIES, AND THE NORTHERN GREAT BASIN, SUN-MON, APR  
14-APR 15.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE NORTHEAST, THE  
CENTRAL GREAT BASIN, THE NORTHERN PLAINS, THE NORTHERN ROCKIES,  
THE CENTRAL ROCKIES, AND THE NORTHERN GREAT BASIN, MON-TUE, APR  
15-APR 16.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE CENTRAL ROCKIES AND  
THE CENTRAL PLAINS, WED-THU, APR 17-APR 18.  
- HEAVY RAIN ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY, THE  
CENTRAL APPALACHIANS, THE TENNESSEE VALLEY, THE GREAT LAKES, THE  
MIDDLE MISSISSIPPI VALLEY, THE MID-ATLANTIC, THE SOUTHERN  
APPALACHIANS, THE SOUTHEAST, THE SOUTHERN PLAINS, AND THE OHIO  
VALLEY, TUE-THU, APR 16-APR 18.  
- HEAVY RAIN ACROSS PORTIONS OF THE SOUTHEAST, THE MID-ATLANTIC,  
THE SOUTHERN APPALACHIANS, AND THE TENNESSEE VALLEY, SUN-MON, APR  
14-APR 15.  
- HEAVY RAIN ACROSS PORTIONS OF THE GREAT LAKES, THE MID-ATLANTIC,  
THE NORTHEAST, THE CENTRAL APPALACHIANS, AND THE OHIO VALLEY,  
MON-TUE, APR 15-APR 16.  
- SEVERE WEATHER ACROSS PORTIONS OF THE SOUTHEAST, THE  
MID-ATLANTIC, THE LOWER MISSISSIPPI VALLEY, THE SOUTHERN  
APPALACHIANS, AND THE TENNESSEE VALLEY, SUN, APR 14.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI  
VALLEY, THE GREAT LAKES, THE UPPER MISSISSIPPI VALLEY, AND THE  
NORTHERN PLAINS.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE LOWER  
MISSISSIPPI VALLEY, THE NORTHERN PLAINS, THE TENNESSEE VALLEY, THE  
NORTHERN GREAT BASIN, THE MIDDLE MISSISSIPPI VALLEY, THE UPPER  
MISSISSIPPI VALLEY, THE PACIFIC NORTHWEST, AND THE OHIO VALLEY.  
- FLOODING LIKELY ACROSS PORTIONS OF THE UPPER MISSISSIPPI VALLEY  
AND THE NORTHERN PLAINS.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE SOUTHERN  
ROCKIES, THE CENTRAL ROCKIES, THE SOUTHERN PLAINS, AND THE CENTRAL  
PLAINS, SUN, APR 14.  
 
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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