681  
FXUS02 KWBC 221901  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EDT TUE MAR 22 2022  
 
VALID 12Z FRI MAR 25 2022 - 12Z TUE MAR 29 2022  
   
..OVERVIEW
 
 
AN AMPLIFIED UPPER LEVEL PATTERN IS EXPECTED TO PREVAIL THROUGH  
THE MEDIUM RANGE PERIOD AS A RIDGE BEGINS TO BUILD OVER THE  
WESTERN U.S. WHILE A BROAD TROUGH IN THE EASTERN U.S. WILL BE  
REINFORCED AND POSSIBLY AMPLIFIED BY INTRUSIONS OF COLDER AIR FROM  
CENTRAL/EASTERN CANADA. A GENERAL COOLING AND DRYING TREND IS  
EXPECTED ACROSS THE NORTHEAST AS POTENTIALLY RECORD-SETTING WARMTH  
IN THE WEST SPREADS EASTWARD INTO THE HIGH PLAINS BY EARLY NEXT  
WEEK. THE MOST UNCERTAIN ASPECT IN THE PATTERN WILL LIKELY BE OFF  
THE WEST COAST WHERE THE TIMING AND AMPLITUDE OF A TROUGH OR  
POTENTIALLY CLOSED LOW WILL AFFECT WHEN AND IF ANY SIGNIFICANT  
PRECIPITATION WILL MOVE ONSHORE FOR EARLY NEXT WEEK. DESPITE THE  
UNCERTAIN WITH THE TIMING OF THE WEST COAST TROUGH, MODEL ENSEMBLE  
MEANS INDICATE DECENT AGREEMENT FOR A SURFACE LOW PRESSURE SYSTEM  
TO DEVELOP IN THE CENTRAL PLAINS BY NEXT TUESDAY.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODEL GUIDANCE THIS MORNING BEGINS WITH GENERALLY GOOD AGREEMENT  
ON SLOWLY PULLING OUT THE LOW PRESSURE SYSTEM OFF NEW ENGLAND ON  
FRIDAY AND INTO THE WEEKEND. MEANWHILE, A CLIPPER SYSTEM IS  
FORECAST TO MOVE ACROSS THE NORTHERN PLAINS AND INTERACT WITH THE  
DEPARTING LOW PRESSURE SYSTEM OVER NEW ENGLAND. MODELS CONTINUE  
TO INDICATE SOME DIFFICULTIES IN TIMING THIS INTERACTION,  
RESULTING IN UNCERTAINTY ON THE SUBSEQUENT DETAILS OF THE TROUGH  
AMPLIFICATION AS WELL AS THE POSITIONS SURFACE FRONTS OVER THE  
EASTERN U.S. THERE IS SOME POTENTIAL FOR MODEST CYCLOGENESIS TO  
OCCUR JUST OFF THE NEW ENGLAND COAST BY ABOUT SUNDAY.  
 
OVER THE WESTERN U.S., MODELS ARE IN GENERAL AGREEMENT WITH A  
RIDGE BUILDING ACROSS THE REGION. IN CONTRAST, MUCH UNCERTAINTY  
LIES OFF THE WEST COAST WHERE AN UPPER TROUGH IS FORECAST TO  
AMPLIFY. MODELS SHOW CONSIDERABLE UNCERTAINTY ON THE SUBSEQUENT  
EVOLUTION OF THIS TROUGH. THE GFS AND CMC MAINTAIN THAT THIS  
FEATURE WILL MOVE INTO THE WESTERN U.S. EARLY NEXT WEEK. THE  
RECENT COUPLE OF RUNS OF ECMWF, HOWEVER, HAVE ABANDONED THIS  
SCENARIO BY CLOSING OFF THIS TROUGH AND DIGS IT SOUTHWARD WELL OFF  
THE WEST COAST. THIS SCENARIO IS POSSIBLE GIVEN THE INCREASINGLY  
HIGH AMPLITUDE NATURE OF THE PATTERN BY THE WEEKEND.  
NEVERTHELESS, THE 00Z EC MEAN APPEARS AT ODDS WITH THE EC  
DETERMINISTIC BY FORMING A LOW PRESSURE SYSTEM OVER CENTRAL PLAINS  
NEXT TUESDAY IN AGREEMENT WITH THE GFS AND CMC, WHICH WOULD IMPLY  
A FASTER PROGRESSION OF THE TROUGH THROUGH THE WESTERN U.S.  
 
THUS THE WPC MEDIUM-RANGE PACKAGE WAS BASED ON THE CONSENSUS OF  
THE 00Z ECMWF/EC MEAN AND THE 06Z GFS/GEFS MEAN, WITH  
INCREASING USAGE OF THE ENSEMBLE MEANS BY DAY 5. A SMALL  
CONTRIBUTION OF THE 00Z CMC WAS INCLUDED FOR DAYS 3-4 FOLLOWED BY  
A SMALL AMOUNT FROM THE CMC MEAN DAYS 5-7. THE RESULTS ARE  
REASONABLY COMPATIBLE WITH WPC CONTINUITY EXCEPT THE TIMING OF LOW  
PRESSURE WAVES OFF THE WEST COAST.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
SNOW IS FORECAST TO LINGER IN MAINE ON FRIDAY AS A LOW PRESSURE  
CENTER SLOWLY EXITS NEW ENGLAND. THEN SHORTWAVE ENERGY AND WEAK  
LOW PRESSURE/FRONTAL SYSTEMS ARE EXPECTED TO PRODUCE LIGHT  
PRECIPITATION AS THEY MOVE ACROSS THE GREAT LAKES REGION TO THE  
CENTRAL/NORTHERN APPALACHIANS AND NORTHEAST LATE WEEK INTO THE  
WEEKEND. SOME OF THE PRECIPITATION WILL BE IN THE FORM OF SNOW IN  
HIGHER ELEVATIONS AND NORTHERN LATITUDES, AND GUSTY WINDS ARE ALSO  
POSSIBLE. PRECIPITATION AHEAD OF THE APPROACHING EASTERN PACIFIC  
UPPER TROUGH IS LIKELY TO REACH THE PACIFIC NORTHWEST AROUND  
FRIDAY AND THEN SPREAD ACROSS MORE OF THE WEST THEREAFTER. MOST  
OF THIS ACTIVITY SHOULD BE IN THE LIGHT TO MODERATE RANGE BUT SOME  
LOCALLY HEAVIER TOTALS COULD BE POSSIBLE DEPENDING ON THE  
UNCERTAIN TIMING OF SYSTEM DETAILS. COVERAGE AND INTENSITY OF  
THIS PRECIPITATION BECOMES MORE UNCERTAIN BY LATE WEEKEND INTO  
EARLY NEXT WEEK.  
 
UNSEASONABLY WARM TEMPERATURES WILL BUILD AND EXPAND UNDERNEATH  
UPPER RIDGING FROM THE WESTERN U.S. INTO THE PLAINS. HIGHS THAT  
ARE 10-20F ABOVE NORMAL WILL BE COMMON OVER CALIFORNIA AND THE  
GREAT BASIN/SOUTHWEST FRIDAY, WITH SOME PLUS 20-25F ANOMALIES  
APPEARING IN THE GREAT BASIN SATURDAY AND MOVING TO THE  
NORTHERN/CENTRAL HIGH PLAINS EARLY NEXT WEEK AS THE UPPER RIDGE  
AXIS SHIFTS. DAILY RECORD TEMPERATURES COULD BE TIED OR SET ACROSS  
CALIFORNIA AND EASTWARD. TEMPERATURES IN THE WEST ARE LIKELY TO  
COOL CLOSER TO NORMAL BY AROUND MONDAY BUT THE EXACT TIMING WILL  
DEPEND ON THE TROUGH'S MOVEMENT INLAND. MEANWHILE THE EAST SHOULD  
SEE NEAR TO SLIGHTLY BELOW AVERAGE TEMPERATURES GIVEN MEAN UPPER  
TROUGHING, WITH COOLEST TEMPERATURES OF 10-15F BELOW NORMAL IN THE  
CENTRAL APPALACHIANS FOR THE WEEKEND AND IN THE GREAT LAKES EARLY  
NEXT WEEK.  
 
KONG/TATE  
 
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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