032  
FXUS02 KWBC 050659  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
158 AM EST SAT MAR 05 2022  
 
VALID 12Z TUE MAR 08 2022 - 12Z SAT MAR 12 2022  
   
..OVERVIEW
 
 
A STRONG RIDGE OVER THE ATLANTIC/GULF OF MEXICO AND THE EASTERN  
PACIFIC SHOULD KEEP MUCH OF THE CONUS WITHIN BROAD AND REINFORCED  
TROUGHING THROUGH MOST OF THE MEDIUM RANGE PERIOD. VARIOUS  
SHORTWAVES WILL PROGRESS THROUGH THE FLOW SENDING LOW PRESSURE  
INTO THE EASTERN U.S. AND THE CENTRAL STATES. AMPLIFIED TROUGHING  
SHOULD BECOME ESTABLISHED OVER THE ROCKIES/INTERIOR WEST BY MID  
WEEK, EVENTUALLY PUSHING EAST INTO THE PLAINS RESULTING IN A  
DEVELOPING LOW PRESSURE AREA TRACKING INTO THE UPPER MIDWEST LATE  
NEXT WEEK. PERIODS OF MODERATE TO LOCALLY HEAVY RAIN ARE POSSIBLE  
ACROSS THE SOUTHEAST, WITH SOME WINTRY WEATHER ACROSS NORTHERN  
AREAS.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
REASONABLY GOOD MODEL AGREEMENT CONTINUES FOR THE LARGE SCALE  
PATTERN OVER THE LAST COUPLE OF MODEL CYCLES, BUT WITH TYPICAL  
TIMING AND DETAIL DIFFERENCES REMAINING, SOME OF WHICH COULD BE  
IMPACTFUL TO SENSIBLE WEATHER. THE INITIAL SHORTWAVE/CLOSED LOW  
OVER THE SOUTHWEST SHOULD WEAKEN AS IT PROGRESSES DOWNSTREAM, BUT  
WITH SOME TIMING UNCERTAINTIES. THE 18Z/MAR 4 GFS AND THE 12Z/MAR  
4 ECMWF SEEMED TO REPRESENT THE BEST MIDDLE GROUND SOLUTION IN  
BETWEEN A FASTER CMC AND SLOWER UKMET. A QUICK LOOK AT THE NEW 00Z  
GUIDANCE (AVAILABLE AFTER FORECAST GENERATION) SHOWS THE GFS AND  
ECMWF ARE A LITTLE FASTER THAN THEIR PREVIOUS RUNS AND CLOSE TO  
THE CMC NOW, WITH THE UKMET STILL NOTABLY SLOWER. THESE SUBTLE  
DIFFERENCES IN TIMING MAY HAVE LARGER IMPACTS TO POTENTIAL QPF  
ACROSS THE SOUTHEAST ALONG A STALLING FRONTAL BOUNDARY.  
 
ENERGY DIVING INTO THE WEST ON WEDNESDAY SHOULD ACT TO REINFORCE  
AND AMPLIFY TROUGHING OVER THE ROCKIES/INTERIOR WEST WHICH  
EVENTUALLY PRESSES EAST INTO THE PLAINS BY FRIDAY/SATURDAY. THIS  
SHOULD INDUCE CYCLOGENESIS IN THE LEE OF THE ROCKIES, WITH A WELL  
DEVELOPED SURFACE LOW LIFTING INTO THE UPPER MIDWEST BY FRIDAY.  
THE 12Z/18Z GUIDANCE FROM YESTERDAY ACTUALLY SHOWED QUITE GOOD  
AGREEMENT TIMING WISE FOR THIS SYSTEM AND SO A MAJORITY  
DETERMINISTIC BLEND WAS USED THROUGH THE PERIOD. INCORPORATED SOME  
OF THE ENSEMBLE MEANS THOUGH TO HELP SMOOTH OUT THE LESS  
PREDICTABLE DETAIL DIFFERENCES. HOWEVER, THE INCOMING 00Z GUIDANCE  
SHOWS MUCH GREATER DIFFERENCES IN SOME OF THE DETAILS AS WELL AS  
TIMING, WITH THE 00Z ECMWF QUITE A BIT SLOWER NOW, SO UNCERTAINTY  
REMAINS HIGH WITH THIS SYSTEM AS A WHOLE.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
RAIN AND THUNDERSTORMS WILL BE WIDESPREAD ALONG AND AHEAD OF A  
COLD FRONT MOVING THROUGH THE EASTERN U.S. ON TUESDAY. BY THE  
MIDDLE OF NEXT WEEK, RETURN FLOW MOISTURE OUT OF THE GULF OF  
MEXICO COULD RESULT IN MULTIPLE DAYS OF RAINFALL ACROSS PARTS OF  
THE LOWER MISSISSIPPI VALLEY/SOUTHEAST. PLENTY OF UNCERTAINTY  
REMAINS WITH RESPECT TO RAINFALL TOTALS, TIMING, AND IMPACTS,  
DEPENDENT ON EXACTLY WHERE THE BOUNDARY STALLS AND POSSIBLE WAVES  
OF LOW PRESSURE. AT THIS POINT, GUIDANCE SUGGESTS THE BETTER  
MOISTURE STAYS SOUTH IN AREAS THAT HAVE BEEN RELATIVELY DRY THE  
PAST FEW WEEKS, BUT JUST A SMALL JOG TO THE NORTH ON THE AXIS,  
COULD BRING HEAVIER RAINFALL INTO AREAS WHICH HAVE SEEN ABOVE  
NORMAL RAIN LATELY, INCREASING THE THREAT FOR FLOODING.  
 
THE NEXT ROUND OF HEAVY MOUNTAIN SNOW ARRIVES INTO THE WEST ON  
TUESDAY AND WEDNESDAY. AS THE SURFACE LOW DEVELOPS ACROSS THE  
CENTRAL U.S. THURSDAY-FRIDAY, SNOW IS LIKELY TO DEVELOP ALONG THE  
NORTH SIDE OF THE LOW FROM THE CENTRAL/NORTHERN PLAINS TO THE  
UPPER MIDWEST. EXACT AMOUNTS AND HOW IMPACTFUL THIS SYSTEM WILL  
ACTUALLY BE REMAINS QUITE UNCERTAIN AT THIS TIME, BUT THE LATEST  
WPC WINTER WEATHER OUTLOOK FOR DAYS 5 AND 6 DO SHOW SOME MODEST  
POTENTIAL FOR ACCUMULATING SNOW.  
 
AFTER A MILD START TO THE WEEK, TEMPERATURES ACROSS THE  
MID-ATLANTIC/NORTHEAST SHOULD MODERATE BACK TOWARDS NORMAL  
TUESDAY-THURSDAY, THOUGH ABOVE NORMAL TEMPERATURES MAY ARRIVE BACK  
ON FRIDAY AHEAD OF THE NEXT SYSTEM. MEANWHILE, THE WEST AND PARTS  
OF THE CENTRAL U.S. WILL GENERALLY BE COOLER THAN AVERAGE THROUGH  
MUCH OF THE PERIOD, BUT PARTICULARLY FOR THE SECOND HALF OF THE  
WEEK AS MORE SUBSTANTIAL TROUGHING DEVELOPS AND PUSHES SOUTHEAST  
ALONG WITH COLD HIGH PRESSURE. TEMPERATURES SHOULD TREND COOLER  
WITH ANOMALIES 10 TO 30 DEGREES BELOW NORMAL POSSIBLE ACROSS THE  
NORTHERN AND CENTRAL PLAINS, AND AS FAR SOUTH AS TEXAS AND  
OKLAHOMA BY FRIDAY. BELOW NORMAL TEMPERATURES SHOULD MOVE INTO THE  
MISSISSIPPI VALLEY AND MIDWEST STATES BY NEXT WEEKEND.  
 
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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