219  
FXUS02 KWBC 022103  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
502 PM EDT MON MAY 02 2022  
 
VALID 12Z THU MAY 05 2022 - 12Z MON MAY 09 2022  
 
...SEVERE WEATHER AND ENHANCED RAINFALL THREAT WITH SOUTHERN  
STREAM CLOSED LOW TRACK THURSDAY INTO SATURDAY...  
...HEAVY SNOW THREAT FROM THE NORTHWEST TO THE NORTH-CENTRAL GREAT  
BASIN/ROCKIES FRIDAY-NEXT MONDAY...  
...ACTIVE PATTERN SET TO TRANSITION TO OMEGA-STYLE BLOCKY PATTERN  
BY EARLY NEXT WEEK...  
 
   
..PATTERN OVERVIEW AND GUIDANCE EVALUATION
 
 
GUIDANCE REMAINS VARIED WITH THE PROGRESSION OF A CLOSED UPPER LOW  
TRACKING INTO THE PLAINS AND EASTWARD, WITH THE GFS/GEFS MEAN  
STILL ON THE FAST SIDE COMPARED TO THE BETTER CLUSTERED AND SLOWER  
RECENT ECMWF/UKMET/CANADIAN AND ECMWF ENSEMBLE MEAN SOLUTIONS. THE  
WPC FORECAST CONTINUES TO LEAN TOWARDS THE SLOWER SIDE OF THE  
FORECAST ENVELOPE, GIVEN CONTINUITY, BUT ALSO THE GENERAL NATURE  
OF A SEPARATED SOUTHERN STREAM FLOW WITH AN EMBEDDED CLOSED  
SYSTEM. LATEST 12 UTC MODELS AND ENSEMBLES CONTINUE TO TREND IN  
THIS GENERAL DIRECTION, BUT THE GFS IS SLIGHTLY SLOWER WITH ITS  
LOW THAN PREVIOUS RUNS. A NON-GFS CONSENSUS ALSO SEEMS TO WORK  
WELL FOR THE REST OF THE COUNTRY AND MAINTAINS GOOD WPC PRODUCT  
CONTINUITY, THOUGH WITH MORE EMPHASIS ON THE ECMWF ENSEMBLE MEAN  
AND NAEFS MEAN INTO DAY 6/7 AMID GROWING FORECAST SPREAD. OUT  
WEST, THERE REMAINS A GENERAL THEME OF LEADING MAIN UPPER  
TROUGHING REACHING THE COAST THURSDAY, WITH A GROWING SIGNAL AND  
GUIDANCE STARTING TO CONVERGE ON THE DEPICTION OF A MORE DIGGING  
SYSTEM OVER THE WEEKEND INTO EARLY NEXT WEEK AS PART OF A  
DEVELOPING OMEGA STYLE BLOCK OVER THE LOWER 48 TO ALSO INCLUDE  
DOWNSTREAM DEVELOPMENT OF AN AMPLIFIED AND WARMING EAST-CENTRAL  
U.S. UPPER RIDGE AND STORMY WESTERN ATLANTIC CLOSED LOW/TROUGH.  
   
..WEATHER/THREAT HIGHLIGHTS
 
 
A CLOSED UPPER TROUGH AND WELL ORGANIZED SURFACE LOW/FRONTAL  
SYSTEM IS EXPECTED TO TRACK FROM THE SOUTH-CENTRAL PLAINS TO THE  
MISSISSPPI VALLEY/MIDWEST TO THE MID-ATLANTIC THURSDAY-SATURDAY.  
THE STORM PREDICTION CENTER SHOWS A THREAT FOR SEVERE WEATHER  
THURSDAY INTO FRIDAY ACROSS PORTIONS OF THE LOWER MISSISSIPPI  
VALLEY. STRONG STORMS ARE ALSO POSSIBLE INTO THE WEEKEND WITH  
SLOW/STEADY DOWNSTREAM TRACK OF THE SYSTEM. UPPER DIFFLUENCE,  
AMPLE MOISTURE INFLOW, AND INSTABILITY WILL ALSO OFFER A THREAT  
FOR ENHANCED COMMA HEAD AND WAVY LEAD/TRAILING FRONTAL RAINFALL  
FOCUS FROM THE MID-LOWER MISSISSIPPI AND OHIO VALLEYS TO THE  
APPALACHIANS/MID-ATLANTIC THURSDAY-SATURDAY.  
 
THE DIGGING OF A MODERATELY AMPLIFIED/DYNAMIC UPPER TROUGH AND  
FRONTAL SYSTEM ENERGIES ACROSS THE WEST COAST AND SUBSEQUENT  
INLAND PROGRESS THURSDAY THROUGH THE WEEKEND WILL BRING A  
WIDESPREAD PRECIPITATION FOCUS FROM THE NORTHWEST THROUGH THE  
NORTH-CENTRAL GREAT BASIN/ROCKIES AND HEIGHT FALLS/COOLING WILL  
FAVOR A THREAT FOR HEAVY TERRAIN FOCUSING SNOWS. UPPER  
DYNAMICS/FRONTAL TRANSLATION SHOULD ALSO SUPPORT AN EMERGING  
CONVECTION/RAINFALL PATTERN WITH LOCAL RUNOFF CONCERNS ACROSS THE  
NORTH-CENTRAL U.S. BY LATER WEEKEND/EARLY NEXT WEEK.  
 
ABOVE NORMAL TEMPERATURES PROGRESS FROM THE WEST ON THURSDAY INTO  
THE CENTRAL/MIDWEST STATES THEREAFTER AS THE PATTERN BEGINS TO  
AMPLIFY AND A STRONG RIDGE SETS UP IN BETWEEN A TROUGH/CLOSED LOW  
OVER THE WEST, AND A BROAD CLOSED LOW ACROSS THE WESTERN ATLANTIC.  
THESE TROUGHS WILL SUPPORT TEMPERATURES AS MUCH AS 10-15 DEGREES  
BELOW NORMAL ACROSS A LARGE PORTION OF THE WEST AND PARTS OF THE  
MID-ATLANTIC.  
 
SANTORELLI/SCHICHTEL  
 
HAZARDS:  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE CASCADES, AND  
NORTHERN IDAHO, FRI, MAY 6.  
- HEAVY RAIN ACROSS PORTIONS OF THE NORTHERN PLAINS, SUN-MON, MAY  
8-9.  
- HEAVY RAIN ACROSS PORTIONS OF ARKANSAS INTO EASTERN OKLAHOMA AND  
NORTHEASTERN TEXAS, THU, MAY 5.  
- HEAVY RAIN ACROSS PORTIONS OF ARKANSAS INTO EASTERN OKLAHOMA,  
NORTHEASTERN TEXAS, AND MISSOURI, MON, MAY 9.  
- HEAVY RAIN ACROSS THE MIDWEST, OHIO VALLEY, CENTRAL  
APPALACHIANS, AND THE MID-ATLANTIC, THU-FRI, MAY 5-MAY 6.  
- SEVERE WEATHER ACROSS PORTIONS OF THE LOWER AND MID-MISSISSIPPI  
VALLEY, THE TENNESSEE VALLEY, AND INTO SOUTHERN PLAINS, THU, MAY 5.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE CENTRAL PLAINS, AS WELL  
AS THE NORTHERN PLAINS AROUND THE RED RIVER VALLEY.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE MISSOURI  
AND THE RED RIVER VALLEY.  
- FLOODING LIKELY ACROSS PORTIONS OF THE RED RIVER.  
 
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC  
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, EXPERIMENTAL EXCESSIVE RAINFALL  
OUTLOOK, 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/#PAGE=ERO  
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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