044  
FXUS02 KWBC 080701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
200 AM EST TUE MAR 08 2022  
 
VALID 12Z FRI MAR 11 2022 - 12Z TUE MAR 15 2022  
 
...WINTER STORM THREATS FOR PARTS OF THE MID-SOUTH TO THE INTERIOR  
NORTHEAST FRIDAY-SATURDAY...  
 
...HEAVY RAINFALL LIKELY ACROSS PORTIONS OF THE SOUTHEAST ON  
FRIDAY...  
 
   
..OVERVIEW
 
 
A POTENT SHORTWAVE IN THE SOUTHERN ROCKIES AND A NORTHERN STREAM  
SHORTWAVE THROUGH THE MIDWEST EARLY FRIDAY WILL COMBINE TO SUPPORT  
STRONG CYCLOGENESIS INTO THE EASTERN U.S. BY SATURDAY. THIS  
CLASSIC SPRING SYSTEM WILL FEATURE SNOW AND COLD TO THE  
NORTH/NORTHWEST OF THE SURFACE LOW, AND WARM/WET CONDITIONS AHEAD  
OF THE COLD FRONT. UPPER FLOW SHOULD THEN BECOME QUASI-ZONAL  
SUNDAY-MONDAY WITH A WEAK SHORTWAVE INTO THE NORTHWEST, THOUGH MAY  
AMPLIFY WITH TIME AS IT REACHES THE EAST ON TUESDAY. THE NEXT  
SHORTWAVE SHOULD REACH THE PACIFIC NORTHWEST BY NEXT TUESDAY AS  
WELL.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE GUIDANCE SEEMS TO BE TRENDING TOWARDS BETTER AGREEMENT WITH  
THE CENTRAL/EASTERN SYSTEM FRIDAY-SATURDAY, ALTHOUGH SOME TIMING  
DIFFERENCES CONTINUE WITH THE COLD FRONT INTO THE EAST. THE GFS  
HAS CONSISTENTLY BEEN ON THE FASTER SIDE OF THE ENVELOPE, ALTHOUGH  
HAS TRENDED SLOWER WITH EACH OF ITS PAST FEW RUNS AND IS NOW IN  
REASONABLE AGREEMENT. THE 12Z/MAR 7 UKMET IS ALSO A HAIR FASTER  
AND ALSO QUICKER TO OCCLUDE THE SYSTEM OVER THE NORTHEAST.  
INCOMING 00Z GUIDANCE TONIGHT OVERALL HAD THE SAME GENERAL  
FEELING, ALTHOUGH THE UKMET WAS SLOWER AND MORE IN LINE. GIVEN THE  
SLOWER TREND SEEN IN ALL THE GUIDANCE THE PAST FEW DAYS, THE WPC  
PROGS FAVORED SOMETHING CLOSER TO THE SLOWER EC/CMC FOR DAYS 3-4,  
HOWEVER, OVERALL THE PATTERN REMAINS RATHER PROGRESSIVE DESPITE  
RAPID DEEPENING OF THE SURFACE LOW, AND FURTHER REFINEMENTS SLOWER  
OR FASTER ARE PROBABLE. AT THIS POINT, THESE ARE DETAILS THAT WILL  
TAKE UNTIL THE SHORT RANGE PERIOD TO FULLY RESOLVE. SO IT'S HARD  
TO THROW ANY SOLUTION OFF THE TABLE AT THIS POINT.  
 
AFTER THIS SYSTEM, DETERMINISTIC MODELS DIVERGE MORE WITHIN A  
QUASI-ZONAL PATTERN. THE 18Z/MARCH 7 GFS IS QUICKER WITH THE FIRST  
SHORTWAVE INTO THE PACIFIC NORTHWEST SUNDAY, BUT THE ECMWF CATCHES  
UP TO IT BY MONDAY ACROSS THE CENTRAL PLAINS AND BOTH ARE RATHER  
PROGRESSIVE DOWNSTREAM. THE 12Z/MAR 7 CMC IS THE REAL OUTLIER  
HERE, WITH A MORE AMPLIFIED SHORTWAVE AND OVERALL SLOWER  
PROGRESSION WHICH EVENTUALLY ENDS UP WITH A CLOSED LOW OVER THE  
LOWER MISSISSIPPI VALLEY NEXT TUESDAY. THE SECOND SHORTWAVE INTO  
THE PACIFIC NORTHWEST EARLY TUESDAY SHOWS PRETTY GOOD AGREEMENT  
RIGHT NOW TIMING WISE. AFTER DAY 5, THE WPC BLEND LEANS  
INCREASINGLY MORE TOWARDS THE ENSEMBLE MEANS (WITH SOME MODEST  
CONTRIBUTIONS FROM THE GFS/ECMWF) TO HELP MITIGATE THE  
DIFFERENCES.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
SHOWERS AND THUNDERSTORMS SHOULD STILL BE ONGOING FRIDAY ACROSS  
THE SOUTHEAST AS A FRONTAL BOUNDARY REMAINS PARKED OVER THE REGION  
WITH AMPLE MOISTURE AND INSTABILITY PRESENT. THIS BOUNDARY SHOULD  
FINALLY BECOME ABSORBED/PUSHED EAST/LIFT NORTHWARD WITH THE STRONG  
COLD FRONT ON SATURDAY THOUGH. RAINFALL WILL COME IN WAVES OVER  
THE SOUTHEAST, SOME OF WHICH COULD BE HEAVY AND FLOODING/FLASH  
FLOODING MAY BE A THREAT ESPECIALLY WHERE MULTIPLE ROUNDS OF  
CONVECTION TRAIN OVER THE SAME AREAS AND COMBINED WITH HEAVY  
RAINFALL THE PREVIOUS DAY IN THE SAME REGION. GIVEN THIS  
POTENTIAL, THE WPC DAY 4 (FRIDAY) NEWLY EXPERIMENTAL EXCESSIVE  
RAINFALL OUTLOOK HIGHLIGHTS A SLIGHT RISK AREA FROM THE FLORIDA  
BIG BEND TO SOUTHEAST GEORGIA.  
 
COLD AIR POURING INTO THE CENTRAL U.S. BEHIND THE DEVELOPING STORM  
SYSTEM INTO FRIDAY WILL SUPPORT RAIN CHANGING TO SNOW BEHIND THE  
FRONT FRIDAY EVENING, WITH ACCUMULATIONS POSSIBLE AS FAR SOUTH AS  
THE LOWER MISSISSIPPI VALLEY. THE RAPIDLY DEEPENING SURFACE LOW  
INTO THE NORTHEAST SHOULD ALLOW FOR POSSIBLY HEAVY SNOW ACROSS THE  
LOWER GREAT LAKES/INTERIOR NORTHEAST. WIDESPREAD, THOUGH QUICK  
MOVING, RAIN IS LIKELY AHEAD OF THE FRONT IN THE EAST.  
 
THE ARCTIC AIRMASS BEHIND THE FRONT WILL BRING DAYTIME HIGHS  
20-30+ DEGREES BELOW NORMAL AS FAR SOUTH AS TEXAS ON FRIDAY.  
OVERNIGHT LOWS ACROSS THE NORTHERN PLAINS AND IN HIGHER ELEVATIONS  
OF THE ROCKIES ARE LIKELY TO BE NEAR OR BELOW ZERO FOR MANY  
LOCATIONS. MODIFYING SOME WITH TIME, THE COLD AIR WILL SHIFT INTO  
THE MIDWEST ON SATURDAY AND THE EASTERN U.S. ON SUNDAY FOLLOWING  
THE FRONTAL PASSAGE (WITH ABOVE NORMAL TEMPS AHEAD OF IT). EVEN  
FOR PARTS OF NORTHERN FLORIDA AND THE SOUTHEAST, LOW TEMPERATURES  
SUNDAY MORNING COULD BE NEAR OR BELOW FREEZING WITH RECORD LOWS  
POSSIBLE IN SOME LOCATIONS. BY NEXT WEEK, PARTS OF THE WEST AND  
CENTRAL U.S. MAY SEE MODERATELY ABOVE NORMAL TEMPERATURES AS  
PERIODIC UPPER RIDGING SLIDES THROUGH.  
 
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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