844  
FXUS02 KWBC 222027  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
425 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 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 OF 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 NEAR THE CANADIAN BORDER FOLLOWED BY STRONG  
AND GUSTY WINDS WITH FALLING TEMPERATURES. PRECIPITATION AHEAD OF  
THE APPROACHING EASTERN PACIFIC UPPER TROUGH IS LIKELY TO REACH  
THE PACIFIC NORTHWEST AROUND FRIDAY. MOST OF THIS ACTIVITY SHOULD  
BE IN THE LIGHT TO MODERATE RANGE BUT SOME LOCALLY HEAVIER TOTALS  
ARE POSSIBLE. BY EARLY NEXT WEEK, PRECIPITATION ASSOCIATED WITH  
AN UPPER TROUGH COULD MOVE INTO THE WESTERN OR SOUTHWESTERN U.S.  
BUT WITH UNCERTAIN TIMING AND INTENSITY OF SYSTEM DETAILS.  
 
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 EAST. 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  
 
HAZARDS:  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE CENTRAL GREAT BASIN,  
CALIFORNIA, AND THE SOUTHWEST, SUN-MON, MAR 27-MAR 28.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE LOWER MISSISSIPPI  
VALLEY, THE SOUTHERN PLAINS, THE UPPER MISSISSIPPI VALLEY, THE  
NORTHERN PLAINS, AND THE TENNESSEE VALLEY.  
- FLOODING LIKELY ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI  
VALLEY, THE UPPER MISSISSIPPI VALLEY, AND THE NORTHERN PLAINS.  
- HIGH WINDS ACROSS PORTIONS OF THE UPPER MISSISSIPPI VALLEY AND  
THE NORTHERN PLAINS, FRI, MAR 25.  
- MUCH ABOVE NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
GREAT BASIN, CALIFORNIA, AND THE SOUTHWEST, FRI-SAT, MAR 25-MAR 26.  
- MUCH ABOVE NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
ROCKIES, THE CENTRAL PLAINS, THE SOUTHERN PLAINS, AND THE NORTHERN  
PLAINS, SUN-MON, MAR 27-MAR 28.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF MAINLAND ALASKA, FRI, MAR  
25.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE ALASKA PANHANDLE,  
MON-TUE, MAR 28-MAR 29.  
 
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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