047  
FXUS02 KWBC 012205  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
504 PM EST TUE MAR 01 2022  
 
VALID 12Z FRI MAR 04 2022 - 12Z TUE MAR 08 2022  
 
...HEAVY SNOW POTENTIAL OVER THE UPPER MIDWEST/GREAT LAKES AND  
POSSIBLY INTO NORTHERN NEW ENGLAND DURING THE WEEKEND...  
 
...HEAVY RAINFALL POTENTIAL FROM THE MID-LOWER MISSISSIPPI VALLEY  
INTO TENNESSEE/OHIO VALLEYS LATE WEEKEND INTO EARLY NEXT WEEK...  
   
..OVERVIEW
 
 
MODELS AND ENSEMBLE MEANS CONTINUE TO SHOW THE ESTABLISHMENT OF A  
POSITIVELY TILTED MEAN TROUGH ALOFT FROM CANADA INTO THE WESTERN  
U.S., BETWEEN A BUILDING EASTERN PACIFIC RIDGE AND ANOTHER RIDGE  
THAT MIGRATES ACROSS THE GULF OF MEXICO INTO THE BAHAMAS. A  
LEADING IMPULSE REACHING THE WEST BY THE START OF THE PERIOD EARLY  
FRIDAY AND ANOTHER FEATURE ARRIVING CLOSE BEHIND WILL BRING  
PRECIPITATION TO PORTIONS OF THE WEST, FOLLOWED BY A BROAD AREA OF  
PRECIPITATION TO THE EAST OF THE ROCKIES AS TWO POTENTIAL SYSTEMS  
TRACK INTO THE GREAT LAKES/OHIO VALLEY. THE FIRST SYSTEM SHOULD  
BRING GREATER SNOWFALL POTENTIAL TO THE UPPER MIDWEST/UPPER GREAT  
LAKES AND TO SOME DEGREE NORTHERN NEW ENGLAND. MOST GUIDANCE SHOWS  
A SECOND SYSTEM DEVELOPING ALONG THE TRAILING FRONT WHOSE SLOW  
MOVEMENT DUE TO ALIGNMENT WITH SOUTHWESTERLY MEAN FLOW ALOFT LATE  
WEEKEND INTO EARLY NEXT WEEK COULD MAKE IT A FOCUS FOR SIGNIFICANT  
RAINFALL FARTHER SOUTH. BELOW NORMAL TEMPERATURES WILL SETTLE OVER  
MUCH OF THE WESTERN AND CENTRAL U.S. WHILE MUCH ABOVE NORMAL  
READINGS FROM THE CENTRAL/SOUTHERN PLAINS INTO THE SOUTHEAST LATE  
THIS WEEK BECOME MORE PRONOUNCED OVER THE EAST.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
WITHIN WHAT CONTINUES TO BE A CONSISTENTLY AGREEABLE PATTERN FROM  
A MULTI-DAY MEAN PERSPECTIVE, OPERATIONAL MODELS CONTINUE TO SHOW  
SOME SPREAD AND VARIABILITY FOR DETAILS AND ARE STILL IN THE  
PROCESS OF REFINING SOME OF THE SPECIFICS UP TO 5-6 DAYS OUT IN  
TIME. THERE ARE SOME COMMON THEMES THOUGH. THE PERIOD BEGINS  
FRIDAY WITH GOOD CONSENSUS FOR THREE PRIMARY SHORTWAVES WITHIN THE  
BROADER WESTERN TROUGH. THE PAST FEW GUIDANCE CYCLES HAVE  
INDICATED THAT THE LEADING SOUTHEASTERNMOST ONE CENTERED OVER  
CALIFORNIA FRIDAY WILL LIKELY BE IN THE FORM OF A COMPACT CLOSED  
LOW THAT CROSSES CALIFORNIA AND THEN EJECTS RAPIDLY NORTHEASTWARD  
(WITH MIXED SIGNALS FOR BEING OPEN OR CLOSED AT VARIOUS VALID  
TIMES). THE SECOND SHORTWAVE NOW HAS BETTER CONSENSUS THAT IT WILL  
TAKE THE FORM OF A CLOSED LOW AS IT GENERALLY FOLLOWS THE TRACK OF  
THE FIRST, MOVING THROUGH THE WEST AND THEN TURNING NORTHEASTWARD.  
THE THIRD IS MOST LIKELY TO TRACK ACROSS SOUTHWESTERN CANADA LATE  
THIS WEEK AND SHEAR OUT EARLY NEXT WEEK, THOUGH WITH ITS ENERGY  
POSSIBLY COMBINING WITH THE INITIAL SHORTWAVE AS IT REACHES THE  
GREAT LAKES. THEN THE 00Z CMC WAS ALONE IN SHOWING ANOTHER SMALL  
CLOSED LOW DIVING SOUTH ALONG THE WEST COAST OVER THE WEEKEND,  
WHICH WAS NOT FAVORED.  
 
AS THE INITIAL SHORTWAVE TRACKS INTO THE MIDWEST/GREAT LAKES BY  
EARLY SUNDAY, THE 00Z AND NEWER 12Z GUIDANCE SEEMS TO HAVE  
STEADIED IN SHOWING DEEPER SOLUTIONS WITH THIS FEATURE AND THE  
ASSOCIATED SURFACE LOW COMPARED TO SOME PREVIOUS RUNS. GUIDANCE  
STILL SIGNALS POTENTIAL FOR SOME WEAKENING BEYOND THE GREAT LAKES  
AS THE ENERGY ALOFT MAY SHEAR OUT TO SOME DEGREE. LATEST GFS/ECMWF  
RUNS AND THEIR MEANS INDICATE THAT THE SECOND EJECTING WESTERN  
IMPULSE MAY LEAD TO ANOTHER WAVE THAT REACHES THE GREAT LAKES OR  
OHIO VALLEY ON A TRACK FARTHER SOUTHEAST THAN THE FIRST ONE AND  
ONLY ABOUT A DAY BEHIND. THERE IS MORE UNCERTAINTY IN POSITION AND  
DEPTH WITH THIS SURFACE LOW, AND THE STRONGEST MODEL THUS FAR IS  
THE 12Z GFS. DETAILS OF ENERGY BEHIND THE SECOND FEATURE BECOME  
INCREASINGLY UNCERTAIN, AS SEEN IN DIFFERENCES AMONG THE  
OPERATIONAL MODELS AS WELL AS BROADENING SPREAD AMONG ENSEMBLE  
MEMBERS. THE OVERALL TRENDS FOR THIS FORECAST UPDATE FOR DAY 7  
WERE A DEEPER TROUGH REBUILDING ACROSS THE WEST, WHICH IS NOW SEEN  
IN THE 12Z ECMWF AND CMC AS WELL, AND A FASTER TREND OF THE COLD  
FRONT TRACKING FARTHER OFFSHORE INTO THE ATLANTIC.  
 
THE UPDATED FORECAST STARTED WITH PRIMARY EMPHASIS ON THE 06Z  
GFS/00Z ECMWF WITH LESSER INPUT FROM THE 00Z CMC/UKMET FOR ABOUT  
THE FIRST HALF OF THE PERIOD, TO REFLECT AN INTERMEDIATE SOLUTION  
AMONG THE GENERAL CLUSTERING THAT EXISTED FOR THE TWO PRIMARY  
UPPER SYSTEMS AND CORRESPONDING SURFACE REFLECTION. THE REASONABLY  
GOOD CLUSTERING IN THE OVERALL PATTERN BUT WITH SOME GREATER  
UNCERTAINTY WITH DETAILS OF TRAILING FLOW LED TO SOME ADDITION OF  
THE ENSEMBLE MEANS PARTICULARLY BY DAY 7, BUT STILL WITH A  
MAJORITY DETERMINISTIC MODEL BLEND. THIS APPROACH YIELDED  
GENERALLY MODEST REFINEMENTS TO CONTINUITY OTHER THAN THE  
AFOREMENTIONED ONES.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
THE SEQUENCE OF TWO UPPER SYSTEMS MOVING INTO AND THROUGH THE WEST  
FROM LATE THIS WEEK THROUGH THE WEEKEND SHOULD SPREAD RAIN AND  
HIGHER ELEVATION SNOW ACROSS THE REGION. MOST ACTIVITY SHOULD BE  
LIGHT TO MODERATE BUT SOME LOCALLY HEAVIER TOTALS WILL BE  
POSSIBLE, PRIMARILY FROM THE SIERRA NEVADA INTO THE WASATCH AND  
CENTRAL ROCKIES. WITH MUCH LOWER CONFIDENCE, ANOTHER SYSTEM THAT  
MAY DROP SOUTHEASTWARD INTO THE NORTHWEST EARLY NEXT WEEK MAY  
PRODUCE SOME LIGHT TO MODERATE PRECIPITATION.  
 
MEANWHILE WEATHER WILL BECOME MORE ACTIVE ACROSS MANY AREAS TO THE  
EAST OF THE ROCKIES FROM THE END OF THIS WEEK INTO EARLY NEXT  
WEEK. THE FIRST WESTERN FEATURE SHOULD GENERATE SURFACE LOW  
PRESSURE THAT TRACKS FROM THE CENTRAL PLAINS THROUGH UPPER GREAT  
LAKES DURING THE WEEKEND. THE BEST POTENTIAL FOR WINTRY  
PRECIPITATION TYPES STILL EXTENDS FROM THE NORTHERN HALF OF THE  
HIGH PLAINS INTO THE UPPER GREAT LAKES AND EVENTUALLY NEW ENGLAND  
(WHERE A CHANGEOVER TO RAIN MAY OCCUR). HIGHEST PROBABILITY OF  
SIGNIFICANT SNOWFALL REMAINS JUST TO THE NORTHWEST OF THE SURFACE  
LOW TRACK, WITH INCREASING CHANCES OVER THE NORTHERN PLAINS AND  
CONTINUED CHANCES OVER THE UPPER MIDWEST. LATEST GUIDANCE SUGGESTS  
THE STORM COULD BE STRONG ENOUGH TO PRODUCE SOME BRISK WINDS BUT  
MODEL BEHAVIOR THUS FAR OFFERS POTENTIAL FOR ADDITIONAL CHANGES IN  
THE FORECAST. RAINFALL OF VARYING INTENSITY WILL BE POSSIBLE OVER  
THE REST OF THE CENTRAL/EAST-CENTRAL U.S. AHEAD OF THE TRAILING  
COLD FRONT. EMBEDDED THUNDERSTORMS COULD BE SEVERE IN THE  
MID-MISSISSIPPI VALLEY ON SATURDAY PER THE LATEST STORM PREDICTION  
CENTER EXTENDED OUTLOOK. THEN THERE IS A CONTINUED SIGNAL FOR  
HEAVIER RAINFALL POTENTIAL GENERALLY WITHIN AN AREA FROM THE  
SOUTHEASTERN PLAINS INTO THE OHIO/TENNESSEE VALLEYS BY SATURDAY  
NIGHT/SUNDAY INTO EARLY NEXT WEEK. THIS THREAT CORRESPONDS TO  
SLOWER PROGRESSION OF THE TRAILING FRONT AS IT BECOMES MORE  
ALIGNED WITH FLOW ALOFT, INTERACTION WITH LOW LEVEL GULF MOISTURE,  
AND THE POSSIBILITY OF ANOTHER WAVE THAT WOULD PROVIDE ADDED  
RAINFALL FOCUS. THE NORTHWESTERN FRINGE OF THIS MOISTURE SHIELD  
SHOULD CONTAIN SOME WINTRY WEATHER, LIKELY ALONG AN AXIS SOMEWHAT  
SOUTHEAST OF THE FIRST EPISODE. SPECIFICS WILL DEPEND ON  
LOWER-CONFIDENCE WAVE DETAILS.  
 
COLDER AIR OVERSPREADING THE WESTERN AND CENTRAL U.S. LATE THIS  
WEEK INTO THE WEEKEND AND PERSISTING THROUGH AT LEAST EARLY NEXT  
WEEK SHOULD YIELD A BROAD AREA OF TEMPERATURES THAT ARE 5-15F  
BELOW NORMAL. SOME POCKETS OF COLDER ANOMALIES ARE POSSIBLE OVER  
THE NORTHERN/CENTRAL HIGH PLAINS, PARTICULARLY IN TERMS OF HIGHS.  
LEADING WARM SECTOR AIR, INITIALLY FOCUSED OVER THE CENTRAL PLAINS  
AND THEN BECOMING MORE PRONOUNCED OVER THE EAST, WILL CONTAIN  
READINGS THAT ARE 10-25F ABOVE NORMAL WITH LOCALIZED HIGHER  
ANOMALIES POSSIBLE FOR MORNING LOWS. NUMEROUS LOCATIONS OVER THE  
SOUTHEAST MAY CHALLENGE DAILY RECORD HIGHS FROM THE WEEKEND INTO  
EARLY NEXT WEEK, WHILE RECORD WARM LOWS MAY EXTEND FARTHER  
NORTHWARD.  
 
TATE/RAUSCH  
 
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  
 
HAZARDS:  
- HEAVY RAIN ACROSS PORTIONS OF THE LOWER/MIDDLE MISSISSIPPI  
VALLEY, THE TENNESSEE VALLEY, THE  
SOUTHERN PLAINS, THE GREAT LAKES, AND THE OHIO VALLEY, SUN-MON,  
MAR 6-MAR 7.  
- HEAVY RAIN ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY, THE  
TENNESSEE VALLEY, THE  
MID-ATLANTIC, THE SOUTHERN APPALACHIANS, THE SOUTHEAST, THE  
SOUTHERN PLAINS, AND THE OHIO VALLEY,  
TUE, MAR 8.  
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL PLAINS, THE GREAT  
LAKES, THE UPPER MISSISSIPPI VALLEY,  
AND THE NORTHERN PLAINS, SAT, MAR 5.  
- SEVERE WEATHER ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY  
AND THE UPPER MISSISSIPPI VALLEY,  
SAT, MAR 5.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE NORTHERN GREAT BASIN.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE PACIFIC  
NORTHWEST, THE OHIO VALLEY, THE  
NORTHERN GREAT BASIN, AND THE TENNESSEE VALLEY.  
- FLOODING LIKELY ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI  
VALLEY, THE PACIFIC NORTHWEST, THE  
NORTHERN ROCKIES, AND THE NORTHERN GREAT BASIN.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE  
NORTHERN/CENTRAL ROCKIES, AND THE  
NORTHERN/CENTRAL PLAINS, SAT-MON, MAR 5-MAR 7.  
- ENHANCED WILDFIRE RISK ACROSS PORTIONS OF THE SOUTHERN PLAINS,  
FRI, MAR 4.  
 
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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