988  
FXUS02 KWBC 231921  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
320 PM EDT WED MAR 23 2022  
 
VALID 12Z SAT MAR 26 2022 - 12Z WED MAR 30 2022  
   
..OVERVIEW
 
 
DEEP TROUGHING OVER THE EASTERN U.S. THIS WEEKEND WILL FAVOR  
SEASONABLY COOL TEMPERATURES FROM THE GREAT LAKES TO THE  
NORTHEAST. A FEW EMBEDDED SHORTWAVES WILL REINFORCE THE COOL  
REGIME AND BRING BLUSTERY CONDITIONS AND MOSTLY LIGHT  
PRECIPITATION. MEANWHILE, A RIDGE ANCHORED OVER THE WEST WILL  
BREAK DOWN AS A LARGE SCALE TROUGH APPROACHES AND BRINGS UNSETTLED  
AND ACTIVE WEATHER TO THE NORTHWEST AND EVENTUALLY MUCH OF THE  
WEST. AS THAT AFOREMENTIONED RIDGE MOVES INTO THE PLAINS,  
TEMPERATURES SOAR TO MUCH ABOVE NORMAL VALUES WHICH COULD BRING  
RECORD HIGHS TO THE INTERMOUNTAIN WEST TO THE HIGH PLAINS.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE SYNOPTIC SETUP AT THE START OF THE PERIOD /SATURDAY/ SHOWS  
GOOD MODEL AGREEMENT AND PREDICTABILITY WITH A WESTERN U.S. RIDGE  
AND EASTERN TROUGH. A FEW EMBEDDED SHORTWAVES WILL MOVE THROUGH  
THE CYCLONIC FLOW THIS WEEKEND OVER THE GREAT LAKES WITH ONE  
PARTICULAR CLIPPER HELPING TO INDUCE CYCLOGENESIS OFF THE NEW  
ENGLAND COAST SUNDAY INTO MONDAY. HERE, MODEL DIFFERENCES ARE  
FAIRLY MINIMAL NOW AND A NEAR EQUAL BLEND OF THE LATEST AVAILABLE  
DETERMINISTIC GUIDANCE WAS USED.  
 
THE LARGER MODEL DIFFERENCES ARE TO THE WEST TIED TO THE  
PROGRESSION AND AMPLITUDE OF AN EASTERN PACIFIC TROUGH,  
PARTICULARLY THE SOUTHERN PIECE OF THAT ENERGY. AS THE POSITIVELY  
TILTED TROUGH AXIS REACHES THE WESTERN U.S., SOME GUIDANCE FAVORS  
CLOSING OFF A UPPER LOW WELL OFFSHORE SOUTHERN CALIFORNIA (I.E.  
00Z ECMWF) WHILE OTHERS ARE CLOSER TO THE COAST/INLAND OR MORE  
PROGRESSIVE (GFS/CMC). THE TREND HAS BEEN FOR A SLOWER SOLUTION  
THAT MAY CLOSE OFF, BUT PERHAPS NOT TO THE DEGREE THE 00Z ECMWF  
(AND ITS PREVIOUS RUNS) SUGGEST. IT LARGELY DEPENDS ON HOW MUCH  
PHASING OR LACK OF WITH THE NORTHERN STREAM - THE ECMWF FAVORS  
MORE SEPARATION AND ALLOWS THE NORTHERN STREAM ENERGY TO RACE OUT  
FASTER COMPARED TO THE MORE PHASED GFS SOLUTION, ESPECIALLY BY DAY  
6/7. EITHER WAY, THE MODELS DO SHOW THAT THE TROUGHING REACHES THE  
ROCKIES INTO THE PLAINS BY THE END OF THE PERIOD WHERE A STRONG  
SURFACE LOW MAY MATERIALIZE. IT'S A LOWER CONFIDENCE FORECAST,  
ESPECIALLY FROM DAY 5 ONWARD AS THE ENERGY REACHES THE  
INTERMOUNTAIN WEST. FOR NOW, THE WPC BLEND FOR DAY 5-7 FAVORED A  
COMPROMISE OF THE ECMWF/GFS WHILE INCLUDING HIGHER WEIGHTS OF THE  
ECENS/GEFS MEANS TO MAINTAIN CONTINUITY SOME WHILE ADDRESSING THE  
UNCERTAINTY.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
THE SHORTWAVE ENERGY PROGRESSION AND STRONG CYCLONIC FLOW OVER THE  
GREAT LAKES WILL PRODUCE MAINLY LIGHT PRECIPITATION ACROSS THE  
GREAT LAKES INTO PORTIONS OF THE CENTRAL TO NORTHERN APPALACHIANS  
AND NORTHEAST THIS WEEKEND. THE EXCEPTION LOOKS TO BE FOR THE  
FAVORED HIGH TERRAIN AND UPSLOPE FLOW AREAS OF WEST VIRGINIA WHERE  
LATE SEASON SNOWFALL ACCUMULATIONS COULD TOTAL SEVERAL INCHES PER  
THE LATEST WINTER WEATHER OUTLOOK PROBABILITIES. AS THE NEXT  
SYSTEM MOVES INTO THE WESTERN U.S. THIS WEEKEND INTO EARLY NEXT  
WEEK, UNSETTLED AND ACTIVE WEATHER IS EXPECTED ON DAY 4 /SUNDAY/  
FOR THE NORTHWEST THEN DAY 5-6 /MONDAY-TUESDAY/ FOR MUCH OF  
CALIFORNIA, BRINGING BENEFICIAL AND WELCOME RAINS TO THE VALLEYS  
WITH THE HIGHER ELEVATION AREAS OF THE SIERRA LIKELY TO SEE  
SEVERAL INCHES OR MORE OF SNOW. AS THAT SYSTEM MOVES INTO THE  
PLAINS AND MIDWEST, ENOUGH COLD AIR ON THE NORTHERN FRINGE OF THE  
PRECIPITATION SHIELD COULD ALLOW FOR A WINTRY MIX BUT DETAILS ARE  
LACKING THAT FAR OUT IN TIME.  
 
UNSEASONABLY WARM TEMPERATURES WILL BUILD AND EXPAND UNDERNEATH  
UPPER RIDGING FROM THE WESTERN U.S. INTO THE PLAINS. HIGHS THAT  
ARE 10-25F ABOVE NORMAL WILL BE COMMON OVER THE WEEKEND FROM THE  
WEST COAST ACROSS THE GREAT BASIN AND SOUTHWEST TO THE PLAINS, AND  
SEVERAL DAILY RECORD HIGH TEMPERATURES COULD BE SET OR TIED. AS  
THE RIDGE AXIS SHIFTS EASTWARD, WARM ANOMALIES OF 15-25F ARE  
LIKELY FOR THE HIGH PLAINS MONDAY WHILE THE WEST COAST MODERATES  
CLOSER TO NORMAL. WARMER THAN NORMAL TEMPERATURES REMAIN FORECAST  
IN THE SOUTH-CENTRAL U.S. ON TUESDAY BUT MAY MODERATE WEDNESDAY  
WHILE PUSHING INTO THE SOUTHEAST. MEANWHILE THE EAST SHOULD SEE  
NEAR TO BELOW AVERAGE TEMPERATURES GIVEN MEAN UPPER TROUGHING,  
WITH COOLEST TEMPERATURES OF 10-20F BELOW NORMAL IN THE GREAT  
LAKES AND CENTRAL APPALACHIANS FOR THE WEEKEND AND SPREADING INTO  
THE NORTHEAST EARLY NEXT WEEK.  
 
TATE/TAYLOR  
 
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.  
- HEAVY RAIN ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY, THE  
TENNESSEE VALLEY, THE MIDDLE MISSISSIPPI VALLEY, THE MID-ATLANTIC,  
THE SOUTHERN APPALACHIANS, THE SOUTHEAST, THE SOUTHERN PLAINS, AND  
THE OHIO VALLEY, WED, MAR 30.  
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL APPALACHIANS, SAT, MAR  
26.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE LOWER MISSISSIPPI  
VALLEY, THE NORTHERN PLAINS, THE TENNESSEE VALLEY, THE GREAT  
LAKES, THE UPPER MISSISSIPPI VALLEY, THE SOUTHEAST, THE SOUTHERN  
PLAINS, AND THE OHIO VALLEY.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE UPPER  
MISSISSIPPI VALLEY AND THE NORTHERN PLAINS.  
- FLOODING LIKELY ACROSS PORTIONS OF THE UPPER MISSISSIPPI VALLEY  
AND THE NORTHERN PLAINS.  
- HIGH WINDS ACROSS PORTIONS OF THE SOUTHEAST, THE MID-ATLANTIC,  
AND THE SOUTHERN APPALACHIANS, SAT, MAR 26.  
- MUCH ABOVE NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
ROCKIES, THE CENTRAL GREAT BASIN, THE NORTHERN ROCKIES, THE  
SOUTHERN ROCKIES, CALIFORNIA, THE NORTHERN GREAT BASIN, AND THE  
SOUTHWEST, SAT-SUN, MAR 26-MAR 27.  
- MUCH ABOVE NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
PLAINS, THE CENTRAL ROCKIES, THE CENTRAL GREAT BASIN, THE NORTHERN  
PLAINS, THE NORTHERN ROCKIES, THE SOUTHERN ROCKIES, THE SOUTHERN  
PLAINS, AND THE SOUTHWEST, SUN-MON, MAR 27-MAR 28.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE NORTHEAST,  
THE CENTRAL APPALACHIANS, THE MID-ATLANTIC, THE UPPER MISSISSIPPI  
VALLEY, THE GREAT LAKES, AND THE OHIO VALLEY, SAT-MON, MAR 26-MAR  
28.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE GREAT  
LAKES, THE MID-ATLANTIC, THE NORTHEAST, AND THE CENTRAL  
APPALACHIANS, SUN-MON, MAR 27-MAR 28.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE ALASKA PANHANDLE,  
MON-WED, MAR 28-MAR 30.  
 
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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