799  
FXUS02 KWBC 060701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
201 AM EST SUN MAR 06 2022  
 
VALID 12Z WED MAR 09 2022 - 12Z SUN MAR 13 2022  
   
..OVERVIEW
 
 
STRONG RIDGE AXES OFF BOTH THE EAST AND WEST COAST SHOULD KEEP  
MUCH OF THE CONUS WITHIN BROAD AND REINFORCED TROUGHING NEXT WEEK.  
A SHORTWAVE DIVING INTO THE PACIFIC NORTHWEST ON WEDNESDAY WILL  
SHIFT SOUTH AND EAST INTO THE CENTRAL AND EVENTUALLY THE EASTERN  
U.S. NEXT WEEKEND. THIS WILL PUSH AN ARCTIC COLD FRONT DOWN THE  
GREAT PLAINS THROUGH FRIDAY WHILE A LOW DEVELOPS ALONG THE FRONT  
AND DEEPENS AS IT LIFTS INTO THE UPPER GREAT LAKES ON FRIDAY.  
EXPECT WINTRY WEATHER TO THE NORTHWEST OF THE LOW FROM THE CENTRAL  
ROCKIES/PLAINS TO THE UPPER MIDWEST, WITH ROUNDS OF SHOWERS AND  
STORMS AHEAD OF THE SYSTEM ACROSS THE SOUTHEAST/MID-ATLANTIC. AS  
THE LOW LIFTS QUICKLY INTO EASTERN CANADA NEXT SATURDAY, THE COLD  
FRONT SHOULD CLEAR THE EAST COAST USHERING IN A MUCH CHILLIER AIR  
MASS. BY NEXT SUNDAY/DAY 7, FLOW ACROSS THE CONUS SHOULD BECOME  
MORE ZONAL WITH WEAK SYSTEMS THROUGH THE NORTHERN TIER STATES.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
FAIRLY GOOD AGREEMENT ON THE ADVANCEMENT OF AMPLIFIED TROUGHING  
ACROSS THE INTERIOR WEST AND INTO THE CENTRAL STATES  
WEDNESDAY-THURSDAY. BY FRIDAY AND BEYOND, MORE DIFFERENCES IN THE  
DETAILS OF POSSIBLE STREAM SPLITTING BEGINS TO EMERGE. NOTABLE  
OUTLIER AMONGST THE 12Z/18Z GUIDANCE FROM YESTERDAY IS THE CMC  
WHICH IS SLOWER AND MUCH MORE AMPLIFIED LATE WEEK, CLOSING OFF AN  
UPPER LOW OVER THE MIDWEST ON SATURDAY (00Z CMC CAME IN GENERALLY  
THE SAME). THIS ALSO GETS IT OUT OF SYNC WITH THE NEXT SHORTWAVE  
ENTERING THE PACIFIC NORTHWEST ON SUNDAY. THE GFS AND ECMWF SHOW  
MUCH BETTER CONSISTENCY WITH THE ENSEMBLE MEANS BUT THERE ARE SOME  
TIMING DIFFERENCES NEXT WEEKEND WITH THE NORTHERN STREAM SHORTWAVE  
INTO THE NORTHEAST (GFS FASTER). ALSO SOME LINGERING UNCERTAINTIES  
WITH REGARDS TO AMPLITUDE AND TIMING OF THE PACIFIC NORTHWEST  
SHORTWAVE NEXT SUNDAY, THOUGH THERE IS PLENTY OF TIME FOR THOSE  
DETAILS TO BE WORKED OUT.  
 
THE WPC BLEND FOR TONIGHT USED A MULTI DETERMINISTIC MODEL  
CONSENSUS DAYS 3-5. FOR 6-7, REMOVED THE CMC DUE TO ISSUES  
OUTLINED ABOVE AND INCREASED CONTRIBUTIONS FROM THE GEFS/ECENS  
ENSEMBLE MEANS TO MITIGATE THE DETAIL DIFFERENCES. WAS ABLE TO  
MAINTAIN AT LEAST 50 PERCENT DETERMINISTIC GFS AND ECMWF WHICH  
HELPED GIVE SOME ADDED DEFINITION TO INDIVIDUAL SYSTEMS.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
A STATIONARY BOUNDARY SETTLING ACROSS THE SOUTHEAST SHOULD KEEP  
SHOWERS AND STORMS IN THE FORECAST WEDNESDAY-FRIDAY. EVEN THOUGH  
AMOUNTS DON'T SEEM OVERLY HIGH FOR ANY GIVEN DAY AT THIS POINT,  
MULTIPLE DAYS OF RAIN MAY INCREASE CONCERNS FOR FLOODING.  
MEANWHILE, A SHORTWAVE THROUGH THE WEST ON WEDNESDAY WILL CONTINUE  
A THREAT FOR HEAVY MOUNTAIN SNOWS FOR PARTS OF THE INTERIOR WEST  
AND CENTRAL ROCKIES. A LOW PRESSURE SPINNING UP IN THE LEE OF THE  
ROCKIES AND LIFTING INTO THE UPPER MIDWEST THURSDAY-FRIDAY BRINGS  
A WINTER STORM THREAT FROM THE CENTRAL PLAINS TO THE UPPER  
MIDWEST. THE ELONGATED UPPER TROUGH SHOULD TAP GULF OF MEXICO  
MOISTURE WITH WIDESPREAD RAIN INTO THE EAST AHEAD OF THE COLD  
FRONT ON FRIDAY. THE NEXT SYSTEM INTO THE NORTHWEST NEXT WEEKEND  
SHOULD INCREASE RAIN AND MOUNTAIN SNOW CHANCES ACROSS THE PACIFIC  
NORTHWEST AND NORTHERN ROCKIES.  
 
ARCTIC SOURCED AIR SPILLS INTO THE PLAINS, WITH DAYTIME HIGHS  
20-30+ DEGREES BELOW NORMAL AS FAR SOUTH AS TEXAS THROUGH FRIDAY.  
OVERNIGHT LOWS ACROSS THE NORTHERN PLAINS WILL LIKELY BE NEAR OR  
BELOW ZERO FOR MANY LOCATIONS. AHEAD OF THE COLD FRONT, ABOVE  
NORMAL TEMPERATURES WILL SPREAD ACROSS THE EASTERN THIRD OF THE  
COUNTRY THURSDAY AND FRIDAY BEFORE BEING REPLACED BY BELOW NORMAL  
TEMPS BY SATURDAY FOLLOWING THE PASSAGE OF THE COLD FRONT. BY NEXT  
SUNDAY, MOST OF THE COUNTRY SHOULD MODIFY CLOSER TO NORMAL AS  
UPPER FLOW BECOME LESS AMPLIFIED.  
 
SANTORELLI  
 
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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