654  
FXUS02 KWBC 030700  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
200 AM EST THU MAR 03 2022  
 
VALID 12Z SUN MAR 06 2022 - 12Z THU MAR 10 2022  
 
...HEAVY RAIN POTENTIAL ACROSS THE MID-MISSISSIPPI VALLEY INTO  
OHIO VALLEY LATE SUNDAY INTO MONDAY...  
   
..OVERVIEW WITH WEATHER HIGHLIGHTS/THREATS
 
 
AN UPPER-LEVEL TROUGH FORECAST TO MOVE THROUGH THE SOUTHWESTERN  
U.S. THIS WEEKEND AND THEN LIFT ACROSS THE PLAINS EARLY NEXT WEEK  
WILL LIKELY SUPPORT THE DEVELOPMENT OF AN ELONGATED LOW PRESSURE  
SYSTEM ALONG A POLAR FRONT TO PROMOTE A HEAVY RAIN EVENT ACROSS  
THE MID-MISSISSIPPI VALLEY INTO OHIO VALLEY INTO MONDAY. A WINTER  
WEATHER EVENT SHOULD BE ENDING ACROSS THE UPPER GREAT LAKES SUNDAY  
MORNING AS THE MEDIUM-RANGE PERIOD BEGINS. THE SYSTEM WILL  
POSSIBLY BRING SOME SNOW/FREEZING RAIN ACROSS NORTHERN NEW ENGLAND  
SUNDAY MORNING AND SOME SNOW MONDAY MORNING. A SWATH OF WINTRY  
PRECIPITATION IS FORECAST TO QUICKLY DEVELOP IN ITS WAKE FROM THE  
CENTRAL PLAINS THROUGH THE LOWER GREAT LAKES AND INTERIOR  
NORTHEAST MONDAY INTO TUESDAY AS THE ELONGATED LOW PRESSURE SYSTEM  
TRACKS ACROSS. THEREAFTER, A FAMILIAR PATTERN WILL TEND TO  
RE-ESTABLISH ACROSS THE U.S. AS NORTHERN STREAM CLIPPERS TEND TO  
SLIDE EAST-SOUTHEAST TOWARD AN EASTERN U.S. BROAD TROUGH WHILE A  
SUBTROPICAL JET TENDS TO LINGER ACROSS THE NORTHERN GULF. AN  
INCREASING CHANCE OF HEAVIER RAINFALL APPEARS TO EMERGE ACROSS THE  
DEEP SOUTH TO THE GULF COAST TOWARD THE LATTER PORTION OF NEXT  
WEEK WITH A STATIONARY FRONT ACROSS THE NORTHERN GULF OF MEXICO  
WHILE A TROPICAL LOW LINGERS INTO THE SOUTHERN GULF. ANOTHER  
SURGE OF ARCTIC AIR APPEARS IN STORE FOR THE NORTHERN PLAINS  
THROUGH MIDWEEK BEHIND THE CLIPPER SYSTEMS. THE EASTERN AND  
SOUTHERN U.S. WILL BE MUCH WARMER THAN NORMAL AT THE START OF THE  
MEDIUM-RANGE PERIOD BUT PROGRESSIVELY COOLER AIR WILL WORK ITS WAY  
ACROSS THESE AREAS THROUGH MIDWEEK.  
 
THE CENTRAL AND SOUTHERN ROCKIES INTO THE NEARBY HIGH PLAINS WILL  
BEGIN THE MEDIUM-RANGE PERIOD WITH THE PASSAGE OF THE UPPER LOW  
INTERACTING WITH AN ARCTIC FRONT. THE SNOW WILL GRADUALLY TAPER  
OFF EARLY NEXT WEEK AS THE UPPER TROUGH EXITS THE REGION. THE  
FOCUS OF MOUNTAIN SNOW WILL THEN SHIFT NORTHWARD ACROSS THE  
NORTHERN ROCKIES AND THE FOOTHILLS BY TUESDAY THROUGH MIDWEEK AS  
THE NEXT SURGE OF ARCTIC AIR ARRIVES FROM CANADA. FOR THE REST OF  
THE WESTERN U.S., DRY AND NEAR NORMAL TEMPERATURES ARE EXPECTED TO  
RETURN BEHIND THE EXITING UPPER TROUGH.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODEL GUIDANCE APPEARS IN REASONABLY GOOD AGREEMENT WITH ONE  
ANOTHER IN PREDICTING THE SYNOPTIC PATTERN EVOLUTION ACROSS THE  
U.S. THROUGH THE MEDIUM-RANGE PERIOD. THE GFS, ESPECIALLY THE 18Z  
RUN, WAS AMONG THE SLOWEST GUIDANCE IN PLACING THE LOW PRESSURE  
CENTER OF THE ONGOING WINTER STORM MOVING ACROSS THE UPPER  
MIDWEST/UPPER GREAT LAKES AS MEDIUM-RANGE STARTS SUNDAY MORNING.  
THE TIMING OF THE ELONGATED LOW PRESSURE SYSTEM IN ITS WAKE ALSO  
PRESENTED SOME MORE ISSUES FOR THE GFS WITH THE 18Z RUN BEING MUCH  
SLOWER THAN ITS ENSEMBLE MEAN AS WELL AS THE ECMWF/EC MEAN. BY  
MIDWEEK NEXT WEEK, THE LARGEST MODEL SPREAD APPEARS TO BE ACROSS  
THE NORTHEAST INTO EASTERN CANADA WHERE THE TIMING OF THE VARIOUS  
CLIPPER SYSTEMS AND THEIR POTENTIAL INTERACTIONS PRESENTED A  
CHALLENGE.  
 
THE WPC MEDIUM-RANGE PACKAGE WAS DERIVED BASED ON A MULTI-MODEL  
CONSENSUS WITH 40% FROM THE 12Z ECMWF/EC MEAN, 40% 18Z+00Z GFS/18Z  
GEFS, AND 20% FROM THE 12Z CMC/CMC MEAN. EXCELLENT WPC CONTINUITY  
WAS MAINTAINED.  
 
KONG  
 
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  
 
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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