484  
FXUS02 KWBC 161902  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EDT WED MAR 16 2022  
 
VALID 12Z SAT MAR 19 2022 - 12Z WED MAR 23 2022  
 
...STRONG LOW PRESSURE SYSTEM WILL LIKELY PRODUCE HEAVY RAIN AND  
SEVERE STORMS ACROSS LARGE SECTIONS OF THE SOUTHERN U.S. TOWARD  
THE TENNESSEE VALLEY BY EARLY NEXT WEEK...  
   
..OVERVIEW
 
 
A RATHER ACTIVE WEATHER PATTERN IS IN STORE FOR THE MEDIUM-RANGE  
PERIOD AS A LOW PRESSURE SYSTEM MOVING THROUGH THE NORTHEAST THIS  
WEEKEND WILL GIVE WAY TO A DEEP UPPER LEVEL TROUGH FORECAST TO  
MOVE QUICKLY THROUGH THE WESTERN U.S. THIS DEEP TROUGH WILL  
LIKELY AMPLIFY AS IT REACHES THE CENTRAL/SOUTHERN PLAINS EARLY  
NEXT WEEK AND EVOLVES INTO AN ELONGATED LOW PRESSURE SYSTEM. A  
LARGE SECTION OF THE SOUTHERN U.S. TO THE TENNESSEE VALLEY WILL  
LIKELY BE IMPACTED BY HEAVY RAIN AND SEVERE STORMS. MEANWHILE ON  
THE BACK SIDE OF THE SYSTEM, THE CENTRAL ROCKIES TO THE FRONT  
RANGE COULD POTENTIALLY BE IMPACTED BY A WINTER WEATHER EVENT.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODEL GUIDANCE THIS MORNING APPEARS TO BE IN RATHER DECENT  
AGREEMENT WITH THE AFOREMENTIONED SYNOPTIC EVOLUTION ACROSS THE  
U.S. THROUGH THE MEDIUM-RANGE PERIOD. THE DETERMINISTIC SOLUTIONS  
BEGIN TO DIVERGE TOWARD THE MIDDLE OF NEXT WEEK AS EXPECTED BUT  
THE ENSEMBLE MEANS STILL SHOW RATHER DECENT AGREEMENT ON THE  
POSITION OF THE SURFACE LOW PRESSURE SYSTEM FORECAST TO FORM OVER  
THE CENTRAL PLAINS. THE GFS CONTINUES TO BE ON THE FASTER SIDE OF  
THE GUIDANCE WITH MORE AGGRESSIVE DOWNSTREAM FRONTAL DEVELOPMENT  
TOWARD THE EAST COAST BY MIDWEEK NEXT WEEK. IN CONTRAST, THE  
ECMWF HAS BEEN SLOWER WITH THE PROGRESSION OF THE TROUGH BY  
DIGGING THE UPPER ENERGY FARTHER SOUTH ACROSS THE SOUTHWEST AND  
INTO THE SOUTHERN PLAINS. THE CANADIAN MODEL HAS BEEN IN BETWEEN  
THESE EXTREMES. OVERALL, THE CONSENSUS APPEARS TO TREND TOWARD  
THE ECMWF'S SIDE ALTHOUGH RECENT ECMWF RUNS HAVE SHOWN SOME MORE  
NORTHERN STREAM DEVELOPMENT.  
 
TAKING THESE FACTORS INTO ACCOUNT, THE WPC FORECAST WAS PRIMARILY  
BASED ON THE CONSENSUS OF 40% 00Z ECMWF/EC MEAN, 40% 06Z GFS/GEFS,  
AND 20% 00Z CMC/CMC MEAN WITH INCREASING CONTRIBUTIONS FROM THE  
ENSEMBLE MEANS TOWARD DAY 7. OVERALL, VERY GOOD AGREEMENT WITH  
WPC CONTINUITY WAS MAINTAINED FOR DAYS 3-5. A SLIGHT SOUTHWARD  
TREND ON THE CYCLONE POSITION WAS NOTED ON DAY 6 , LEADING TO A  
SOUTH/EASTWARD PUSH OF THE HEAVY RAIN AXIS ACROSS THE MID-SOUTH.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
THE SURFACE LOW TRACKING FROM THE OHIO VALLEY TO THE NORTHEAST ON  
SATURDAY WILL LIKELY BE ACCOMPANIED BY A SWATH OF MODERATE TO  
LOCALLY HEAVY SNOW ACROSS NORTHERN PORTIONS OF NEW ENGLAND,  
PARTICULARLY CENTRAL AND NORTHERN MAINE. ELSEWHERE, MODERATE RAIN  
IS EXPECTED FROM THE NORTHERN MID-ATLANTIC TO CENTRAL/SOUTHERN NEW  
ENGLAND FOR THE FIRST HALF OF THE WEEKEND.  
 
ATTENTION THEN TURNS TO THE PLAINS AND GULF COAST REGION AS AN  
ELONGATED SURFACE LOW EXITING THE CENTRAL/SOUTHERN ROCKIES BEGINS  
TO INTENSIFY OVER THE CENTRAL PLAINS BY EARLY MONDAY WHILE TAPING  
INTO A SURGE OF GULF MOISTURE ACROSS TEXAS AND THE CENTRAL GULF  
COAST REGION. THE PROSPECTS FOR SEVERE WEATHER WILL EXPAND FROM  
EASTERN TEXAS TO THE CENTRAL GULF COAST STATES FROM MONDAY TO  
TUESDAY WHEREAS THE HEAVY RAINFALL THREAT WILL BE FARTHER INLAND  
FROM THE LOWER TO MID-MISSISSIPPI VALLEY NORTHEASTWARD TO THE  
TENNESSEE VALLEY. FLOODING RAIN COULD BECOME AN ISSUE AS MULTIPLE  
ROUNDS OF CONVECTION DEVELOP OVER THE SAME GENERAL AREAS. THE  
STORM PREDICTION CENTER HAS ADDITIONAL INFORMATION PERTAINING TO  
THE SEVERE WEATHER POTENTIAL. ON THE BACK SIDE OF THE STORM, THE  
AIR MASS COULD BE COLD ENOUGH TO SUPPORT A WINTER WEATHER EVENT  
ACROSS THE CENTRAL ROCKIES INTO THE FRONT RANGE ON MONDAY AND  
POSSIBLY INTO TUESDAY. SOME WINTRY PRECIPITATION COULD ALSO  
DEVELOP OVER THE UPPER MIDWEST/UPPER GREAT LAKES WEDNESDAY MORNING  
AS THE THREAT OF HEAVY RAIN EDGES TOWARD THE APPALACHIANS.  
 
IN TERMS OF TEMPERATURES, THE EAST COAST SHOULD CONTINUE TO HAVE  
ABOVE NORMAL READINGS THIS WEEKEND AND INTO THE MIDDLE OF NEXT  
WEEK AS UPPER LEVEL RIDGING DEVELOPS AHEAD OF THE DEEP TROUGH OVER  
THE PLAINS. EVEN GREATER POSITIVE ANOMALIES ARE LIKELY ACROSS THE  
CENTRAL AND NORTHERN PLAINS BY SUNDAY AHEAD OF THE STORM SYSTEM,  
WITH HIGHS UP TO 25 DEGREES ABOVE AVERAGE, WHEREAS A RETURN TO  
SLIGHTLY BELOW AVERAGE TEMPERATURES IS EXPECTED ACROSS THE ROCKIES  
AND THE WESTERN HIGH PLAINS UNDER THE UPPER LEVEL TROUGH FOR  
MONDAY AND TUESDAY. NO MAJOR SURGES OF ARCTIC AIR ARE EXPECTED.  
 
KONG/HAMRICK  
 
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  
 
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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