944  
FXUS02 KWBC 091936  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
335 PM EDT TUE APR 09 2019  
 
VALID 12Z FRI APR 12 2019 - 12Z TUE APR 16 2019  
 
...MAJOR WINTER STORM TRACKING ACROSS THE UPPER GREAT LAKES  
FRIDAY...  
...HEAVY RAINFALL THREAT FROM EASTERN TEXAS/LOWER MISSISSIPPI  
VALLEY NORTHEASTWARD DURING THE WEEKEND TO MONDAY...  
   
..OVERVIEW AND GUIDANCE ASSESSMENT/PREFERENCES
 
 
THE ROBUST STORM SYSTEM OVER THE GREAT LAKES REGION WILL CONTINUE  
TO LIFT NORTH AND EAST INTO CANADA SPREADING WINTRY PRECIPITATION  
ALONG WITH IT. AS THE CENTRAL LOW PRESSURE EXITS/WEAKENS THE WIND  
SPEEDS WILL BEGIN TO RELAX OVER THE NORTHERN U.S. MEANWHILE, A  
SYSTEM WILL EXIT THE SOUTHWEST/SOUTHERN ROCKIES THIS WEEKEND  
BRINGING WIDESPREAD RAIN TO MUCH OF EASTERN TEXAS, LOWER  
MISSISSIPPI AND WESTERN TENNESSEE VALLEY WITH THE POTENTIAL FOR  
EXCESSIVE RAINFALL AND FLASH FLOODING. A SURFACE LOW IS EXPECTED  
TO FORM ALONG THE BOUNDARY AND AID IN THE PROGRESSIVE TRACK TOWARD  
THE OHIO VALLEY. MODEL GUIDANCE SUGGEST THAT THIS SYSTEM WILL  
OCCLUDE, WITH A NEW LOW FORMING NEAR THE MID ATLANTIC COAST AND  
PROCEEDING NORTHEAST NEAR OR OFF THE NEW ENGLAND COAST EARLY NEXT  
WEEK.  
 
MULTIPLE SHORTWAVES MOVING ONSHORE THE PACIFIC NORTHWEST OVER THE  
COURSE OF THE COMING WEEK WILL BRING PRECIPITATION TO THE COASTS  
OF WASHINGTON AND OREGON AND ELEVATED SNOW TO THE CASCADES. THIS  
ENERGY WILL TRANSLATE OVER INTO THE NORTHERN HIGH PLAINS.  
 
THE LATEST RUNS OF THE GFS HAVE BEEN FASTER/EAST THAN THE REST OF  
THE OPERATIONAL SOLUTIONS. ALTHOUGH THE TREND OVER THE LAST FEW  
CYCLES HAVE FAVORED A MORE PROGRESSIVE TRACK AS IT REACHES THE  
EASTERN U.S., THE GFS HAS BEEN TOO QUICK. AS SUCH THE USE AND  
WEIGHTING OF IT WAS RELATIVELY LIGHT EARLY ON AND NEGLIGIBLE AFTER  
SUNDAY. THE CMC, UKMET AND THE ECWMF WERE MUCH BETTER CLUSTERED  
OVER MOST OF THE CONUS AND PICKED UP MORE DETAILS OF THE SYSTEM  
LEAVING THE GREAT BASIN AND ENTERING THE SOUTHERN/CENTRAL PLAINS.  
 
   
..WEATHER HIGHLIGHTS/HAZARDS
 
 
CONSENSUS STILL DISPLAYS A HIGH POTENTIAL FOR HEAVY SNOWFALL AND  
STRONG WINDS--LEADING TO A PERIOD OF BLOWING SNOW AND POSSIBLE  
BLIZZARD CONDITIONS INTO THE UPPER GREAT LAKES FRIDAY. SOME  
STRONG TO SEVERE CONVECTION WILL BE POSSIBLE FARTHER  
SOUTH/SOUTHEAST IN THE WARM SECTOR IN THE OHIO VALLEY THURSDAY.  
THE WEEKEND SYSTEM DIGGING INTO THE WEST WILL SPREAD LIGHT VALLEY  
RAIN AND HIGH ELEVATION SNOW ACROSS THE REGION.  
 
THIS SYSTEM WILL LEAD TO A HEAVY RAINFALL THREAT FROM EASTERN  
TEXAS AND THE LOWER MISSISSIPPI VALLEY REGION INTO THE  
APPALACHIANS, MID-ATLANTIC AND SOUTHERN NEW ENGLAND, AND POSSIBLY  
INCLUDING THE OHIO VALLEY. THE HIGHEST FORECAST RAINFALL AMOUNTS  
ARE CENTERED OVER THE LOWER MS VALLEY.  
 
THE PACIFIC NORTHWEST AND NORTHERN ROCKIES SHOULD SEE ADDITIONAL  
PRECIPITATION AFTER THE LATE WEEK SYSTEM IN ASSOCIATION WITH  
FRONTAL SYSTEMS MOVING ONSHORE AND INLAND.  
 
THE COLD TEMPERATURE ANOMALIES WILL BE OVER THE ROCKIES/PLAINS  
FRIDAY-SATURDAY, BEHIND THE INITIAL GREAT LAKES STORM (PEAKING  
20-25 DEGREES BELOW NORMAL IN THE CENTRAL TO NORTHERN CENTRAL  
PLAINS. ALSO DURING FRIDAY-SATURDAY EXPECT ABOVE NORMAL  
TEMPERATURES OVER THE EAST, ESPECIALLY FOR MORNING LOWS WHICH MAY  
BE 10-20F ABOVE NORMAL IN THE UPPER OHIO VALLEY/APPALACHIANS FRI  
AND COASTAL MID ATLANTIC TO SOUTHERN NEW ENGLAND SATURDAY. EXPECT  
READINGS TO MODERATE OVER MUCH OF THE LOWER 48 EARLY NEXT WEEK,  
WITH SLIGHTLY BELOW NORMAL TEMPS UNDER THE ROCKIES UPPER TROUGH  
AND ABOVE NORMAL IN RETURN FLOW IN THE SOUTHERN TO CENTRAL PLAINS.  
 
CAMPBELL  
 
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 AND  
THE NORTHERN GREAT BASIN, TUE, APR 16.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE CENTRAL ROCKIES, THE  
CENTRAL GREAT BASIN, THE NORTHERN ROCKIES, AND THE NORTHERN GREAT  
BASIN, MON, APR 15.  
- HEAVY RAIN ACROSS PORTIONS OF THE PACIFIC NORTHWEST, TUE, APR 16.  
- HEAVY RAIN ACROSS PORTIONS OF THE MID-ATLANTIC, THE LOWER  
MISSISSIPPI VALLEY, THE CENTRAL APPALACHIANS, THE TENNESSEE  
VALLEY, THE GREAT LAKES, THE MIDDLE MISSISSIPPI VALLEY, THE  
NORTHEAST, THE SOUTHERN APPALACHIANS, THE SOUTHEAST, THE SOUTHERN  
PLAINS, AND THE OHIO VALLEY, SAT-SUN, APR 13-APR 14.  
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL PLAINS AND THE  
SOUTHERN PLAINS, SAT, APR 13.  
- SEVERE WEATHER ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY  
AND THE SOUTHERN PLAINS, SAT, APR 13.  
- SEVERE WEATHER ACROSS PORTIONS OF THE SOUTHEAST, THE LOWER  
MISSISSIPPI VALLEY, THE SOUTHERN APPALACHIANS, AND THE TENNESSEE  
VALLEY, SUN, APR 14.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE CENTRAL PLAINS, 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  
PACIFIC NORTHWEST, THE NORTHERN ROCKIES, THE MIDDLE MISSISSIPPI  
VALLEY, THE NORTHERN GREAT BASIN, THE UPPER MISSISSIPPI VALLEY,  
THE SOUTHERN PLAINS, AND THE OHIO VALLEY.  
- FLOODING LIKELY ACROSS PORTIONS OF THE UPPER MISSISSIPPI VALLEY,  
THE PACIFIC NORTHWEST, THE NORTHERN PLAINS, THE NORTHERN GREAT  
BASIN, AND THE TENNESSEE VALLEY.  
- HIGH WINDS ACROSS PORTIONS OF THE CENTRAL PLAINS, THE MIDDLE  
MISSISSIPPI VALLEY, THE UPPER MISSISSIPPI VALLEY, AND THE NORTHERN  
PLAINS, FRI, APR 12.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
PLAINS, THE CENTRAL ROCKIES, THE NORTHERN PLAINS, THE SOUTHERN  
ROCKIES, THE UPPER MISSISSIPPI VALLEY, AND THE SOUTHERN PLAINS,  
FRI-SUN, APR 12-APR 14.  
 
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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