371  
FXUS02 KWBC 171900  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EDT THU MAR 17 2022  
 
VALID 12Z SUN MAR 20 2022 - 12Z THU MAR 24 2022  
 
...STRONG LOW PRESSURE SYSTEM WILL LIKELY PRODUCE HEAVY  
RAIN/SEVERE STORMS ACROSS PORTIONS OF THE SOUTHERN U.S. AND HEAVY  
CENTRAL ROCKIES SNOW BY EARLY NEXT WEEK...  
   
..OVERVIEW
 
 
ENERGY WITHIN AN AMPLIFIED UPPER TROUGH MOVING INTO THE WEST  
DURING THE WEEKEND SHOULD PRODUCE A CLOSED LOW OVER THE SOUTHERN  
ROCKIES BY EARLY MONDAY, FOLLOWED BY NORTHEASTWARD PROGRESSION OF  
THE UPPER LOW AND ASSOCIATED STRONG SOUTHERN PLAINS SURFACE LOW  
PRESSURE INTO MID-LATE WEEK. THIS SYSTEM WILL SPREAD A BROAD AREA  
OF SIGNIFICANT WEATHER FROM THE ROCKIES EASTWARD--POTENTIALLY  
HEAVY SNOW OVER THE CENTRAL ROCKIES AND VICINITY, HEAVY RAIN OVER  
CENTRAL/SOUTHERN LATITUDES OF THE EASTERN HALF OF THE COUNTRY, AND  
SEVERE THUNDERSTORMS FROM TEXAS THROUGH THE DEEP SOUTH. SOME  
PRECIPITATION IN THE NORTHERN FRINGE OF THE MOISTURE SHIELD COULD  
BE IN THE FORM OF SNOW. BEHIND THIS SYSTEM A STRONG UPPER RIDGE  
WILL BUILD INTO THE WEST, BRINGING MOSTLY DRY AND WARM WEATHER TO  
THE REGION. A LEADING SYSTEM WILL DEPART FROM NEW ENGLAND ON  
SUNDAY.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE 00Z/06Z CYCLE OF GUIDANCE OFFERS A COMBINATION OF REFINEMENTS,  
ONGOING DISCREPANCIES, AND TRENDS OVER THE FORECAST DOMAIN.  
LATEST SOLUTIONS ARE GENERALLY BECOMING BETTER DEFINED WITH THE  
UPPER LOW LIKELY TO CLOSE OFF OVER NEW MEXICO BY EARLY MONDAY AND  
THEN CONTINUE NORTHEASTWARD OVER THE PLAINS, INCLUDING HOLDING  
ONTO AN UPPER LOW (OR IMPLIED LOW, DEPENDING ON THE CONTOUR  
INTERVAL OF UPPER HEIGHTS) SOMEWHAT LONGER DUE TO SLIGHTLY LATER  
PHASING WITH INCOMING NORTHERN STREAM ENERGY. UPSTREAM, RECENT  
GUIDANCE HAS BEEN VERY INCONSISTENT WITH WHAT WILL HAPPEN AS  
PACIFIC ENERGY ENCOUNTERS THE UPPER RIDGE BUILDING INTO WESTERN  
NORTH AMERICA, AFFECTING SOME ASPECTS OF THE CENTRAL U.S. STORM.  
MULTI-DAY MODEL/ENSEMBLE MEAN TRENDS HAVE GENERALLY BEEN TOWARD A  
STRONGER RIDGE. MEANWHILE GUIDANCE IS SPLIT OVER IMPORTANT  
DETAILS OF EASTERN NORTH AMERICA FLOW DURING MONDAY-WEDNESDAY.  
THE ECMWF/ECMWF MEAN AND UKMET SHOW STRONGER EAST-CENTRAL CANADA  
UPPER RIDGING AND BETTER CONNECTION WITH THE EASTERN U.S. RIDGE,  
LEADING TO MORE NORTHEAST TROUGHING VERSUS THE GFS/GEFS MEAN AND  
CMC/CMC MEAN. THIS ULTIMATELY LEADS TO SOME SIGNIFICANT  
DIFFERENCES IN SURFACE PATTERN AND PRECIPITATION COVERAGE OVER THE  
EAST. THUS FAR THE MORE PROBABLE SOLUTION APPEARS INCONCLUSIVE  
FROM TRENDS, THOUGH THE AMPLIFIED NATURE OF THE UPSTREAM PATTERN  
COULD TILT THINGS A BIT TOWARD THE ECMWF CLUSTER. THE 00Z CMC  
BECAME QUESTIONABLY SUPPRESSED WITH ITS SURFACE PATTERN LATE IN  
THE PERIOD.  
 
AN OPERATIONAL MODEL BLEND PROVIDED A GOOD DEPICTION OF CONSENSUS  
FOR THE FIRST HALF OF THE PERIOD. THEN THE FORECAST TRENDED TO A  
BLEND OF THE 06Z GFS/GEFS MEAN AND 00Z ECMWF/ECMWF MEAN AS DETAIL  
UNCERTAINTIES INCREASED WITHIN A FAIRLY AGREEABLE LARGE SCALE  
PATTERN.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
THE SURFACE LOW DEPARTING FROM THE NORTHEAST ON SUNDAY WILL LIKELY  
PRODUCE SOME LINGERING RAIN/SNOW SHOWERS ACROSS THE REGION.  
OTHERWISE THE EAST WILL SEE FAIRLY DRY WEATHER INTO THE START OF  
NEXT WEEK. GUIDANCE DISCREPANCIES LEAD TO LOW CONFIDENCE FOR WHAT  
COULD BE A NARROW BAND OF PRECIPITATION OVER PARTS OF THE GREAT  
LAKES/NORTHEAST AROUND MONDAY. ATTENTION THEN TURNS TO THE  
CENTRAL U.S. AS A FAIRLY STRONG SURFACE LOW DEVELOPS OVER THE  
SOUTHERN PLAINS BY MONDAY, WITH LEADING LOW LEVEL GULF INFLOW AND  
A WARM FRONT LIFTING NORTHWARD HELPING TO FOCUS A THREAT OF HEAVY  
RAINFALL OVER PARTS OF THE SOUTHERN PLAINS/LOWER MISSISSIPPI  
VALLEY AND EVENTUALLY FARTHER EASTWARD. THERE IS A STRONG MODEL  
SIGNAL FOR HEAVY RAINFALL THAT COULD RESULT IN INSTANCES OF FLASH  
FLOODING, MAINLY LATER IN THE DAY MONDAY AND ESPECIALLY INTO  
TUESDAY AND PERSISTING INTO EARLY WEDNESDAY. THERE IS ALSO A  
THREAT OF SEVERE THUNDERSTORMS FROM EASTERN TEXAS EASTWARD ACROSS  
THE SOUTHERN TIER STATES. CHECK THE LATEST STORM PREDICTION  
CENTER OUTLOOKS FOR THE UPDATED INFORMATION ON THE SEVERE THREAT.  
MEANWHILE PARTS OF THE CENTRAL ROCKIES AND VICINITY MAY SEE A  
PERIOD OF HEAVY SNOWFALL WITH SIGNIFICANT RAINFALL POSSIBLY  
EXTENDING INTO THE CENTRAL PLAINS (BUT LIKELY SOMEWHAT LOWER  
TOTALS THAN EXPECTED TO THE SOUTHEAST). PRECIPITATION COVERAGE  
FROM THE NORTHERN PLAINS INTO NORTHEAST HAS MUCH LOWER CONFIDENCE,  
BUT IF MOISTURE REACHES THAT FAR NORTH SOME PRECIPITATION COULD BE  
IN THE FORM OF SNOW.  
 
AHEAD OF THE DEVELOPING PLAINS STORM, ABOVE NORMAL TEMPERATURES  
WILL PROGRESS FROM THE PLAINS INTO THE EAST. SOME READINGS COULD  
BE AS HIGH AS 20-25F ABOVE NORMAL OVER PARTS OF THE NORTHERN  
PLAINS/MIDWEST ON SUNDAY-MONDAY. FARTHER EASTWARD THE GREATEST  
ANOMALIES SHOULD BE IN THE PLUS 10-20F RANGE WITH MORNING LOWS  
TENDING TO BE WARMER RELATIVE TO NORMAL VERSUS THE HIGHS DUE TO  
THE MOISTURE/CLOUDS. SYSTEM PASSAGE WILL BRING AN AREA OF BELOW  
NORMAL TEMPERATURES FROM THE WEST INTO THE PLAINS, WITH SOME AREAS  
OF HIGHS 10-20F BELOW NORMAL. COOLEST HIGHS RELATIVE TO NORMAL  
SHOULD BE OVER THE SOUTHERN HALF OF THE HIGH PLAINS ON TUESDAY.  
THE UPPER RIDGE BUILDING INTO THE WEST WILL PROMOTE A SIGNIFICANT  
WARMING TREND OVER THE REGION WITH EXPANDING COVERAGE OF HIGHS  
10-20F OR SO ABOVE NORMAL FROM TUESDAY ONWARD. BEST POTENTIAL FOR  
TEMPERATURES TO CHALLENGE DAILY RECORD HIGHS WILL BE OVER  
CALIFORNIA. ALSO, A FEW DAILY RECORD HIGHS COULD BE POSSIBLE OVER  
THE FLORIDA PENINSULA AROUND TUESDAY-WEDNESDAY.  
 
RAUSCH/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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