303  
FXUS02 KWBC 191901  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EDT SAT MAR 19 2022  
 
VALID 12Z TUE MAR 22 2022 - 12Z SAT MAR 26 2022  
 
...HEAVY RAIN WILL LIKELY IMPACT THE DEEP SOUTH TO THE TENNESSEE  
VALLEY TUESDAY-WEDNESDAY AHEAD OF A STRONG LOW PRESSURE SYSTEM AS  
SEVERE STORMS MOVE ACROSS THE GULF COAST STATES AND SOME WINTRY  
WEATHER ACROSS THE NORTHERN TIER...  
   
..OVERVIEW
 
 
THE MOST ACTIVE WEATHER DURING THE MEDIUM-RANGE WILL LIKELY BE  
FROM TUESDAY TO WEDNESDAY AS A STRONG LOW PRESSURE SYSTEM  
INTENSIFIES OVER THE CENTRAL/SOUTHERN PLAINS AND TRACKS TOWARD THE  
GREAT LAKES. THE HEAVIEST RAINFALL IS EXPECTED FARTHER INLAND  
FROM THE DEEP SOUTH TO THE TENNESSEE AND LOWER OHIO VALLEY WHILE  
SEVERE STORMS ARE FORECAST TO TRACK ACROSS THE GULF COAST STATES.  
RAIN INTENSITY SHOULD BE TRENDING DOWNWARD AS THE SYSTEM IS  
FORECAST TO MOVE THROUGH THE EASTERN U.S. MID TO LATE NEXT WEEK.  
ON THE COLD SIDE OF THE SYSTEM, HEAVY SNOW/WINTRY WEATHER SHOULD  
BE ENDING BY EARLY TUESDAY MORNING OVER THE CENTRAL ROCKIES INTO  
THE HIGH PLAINS, BUT SOME PRECIPITATION SHOULD PROGRESS THROUGH  
THE NORTHERN TIER AND INTO THE INTERIOR NORTHEAST. BEHIND THIS  
SYSTEM A STRONG UPPER RIDGE WILL BUILD INTO THE WEST, BRINGING  
POTENTIALLY RECORD HIGH TEMPERATURES TO PARTS OF CALIFORNIA  
MIDWEEK.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODEL GUIDANCE THIS MORNING CONTINUES TO INDICATE THE LIKELIHOOD  
OF AN INTENSIFYING LOW PRESSURE SYSTEM TO TRACK ACROSS THE  
CENTRAL/SOUTHERN PLAINS TUESDAY AS IT INTERACTS WITH A SURGE OF  
COLDER AIR INTRUDING FROM THE NORTHWESTERN QUADRANT OF THE SYSTEM.  
THE TREND HAS BEEN FOR THE COLD AIR INTRUSION TO BE STRONGER  
THAN EARLIER FORECASTS, WITH THE CYCLONE EVOLVING TOWARD A MORE  
CLASSICAL OCCLUSION CONFIGURATION BY WEDNESDAY AS IT TRACKS TOWARD  
THE GREAT LAKES. THIS HAS LED TO A BETTER-DEFINED PRECIPITATION  
SHIELD ACROSS THE GREAT LAKES, AND WITH A TENDENCY FOR THE WESTERN  
EDGE OF THE PRECIPITATION TO EXTEND FURTHER BACK INTO THE UPPER  
MIDWEST. THE CANADIAN MODEL (CMC) WAS MOST AGGRESSIVE WITH THIS  
OCCLUSION PROCESS, LEADING TO A MUCH SLOWER EXIT OF THE SYSTEM  
ACROSS THE EASTERN U.S. LATE NEXT WEEK, ESPECIALLY THE 00Z RUN.  
THE GFS HAS ALSO SLOWED DOWN THE EXIT OF THIS SYSTEM LATER NEXT  
WEEK TO BETTER AGREE WITH THE ECMWF SOLUTIONS, WHICH IS NOT QUITE  
AS SLOW AS THE 00Z CMC. THE 12Z CMC WAS MUCH MORE AGREEABLE WITH  
THE ECMWF-GFS CONSENSUS.  
 
OFF THE PACIFIC NORTHWEST, SOME MODEL DIFFERENCES WERE NOTED  
REGARDING THE TIMING OF SHORTWAVE ENERGIES MOVING TOWARD THE  
COAST. THE CMC WAS MUCH TOO FAST IN BRING THE NEXT SHORTWAVE  
ONSHORE BY DAY 4. THE ECMWF AND THE GFS REASONABLY AGREE WITH  
EACH OTHER IN THIS REGARD.  
 
THEREFORE, THE WPC MEDIUM-RANGE PACKAGED WAS BASED MAINLY ON THE  
CONSENSUS OF THE 00Z ECMWF/EC MEAN AND THE 06Z GFS/GEFS MEAN, WITH  
INCREASING USAGE OF THE ENSEMBLE MEANS TOWARD THE END OF NEXT  
WEEK. A SMALL CONTRIBUTION OF THE 00Z CMC WAS INCLUDED FOR DAYS  
3-4 FOLLOWED BY A SMALL AMOUNT FROM THE CMC MEAN DAYS 5-7. THE  
RESULTS ARE REASONABLY COMPATIBLE WITH WPC CONTINUITY.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
AMPLE GULF OF MEXICO MOISTURE FLOWING INTO THE SURFACE/UPPER-LEVEL  
LOWS TRACKING NORTHEASTWARD OVER THE CENTRAL U.S. WILL LEAD TO  
WIDESPREAD RAIN AND THUNDERSTORMS FOR THE MISSISSIPPI VALLEY TO  
THE EAST COAST PARTICULARLY ON TUESDAY AND WEDNESDAY AHEAD OF THE  
COLD FRONTS. STORMS COULD BE SEVERE ACROSS THE DEEP SOUTH DOWN TO  
THE GULF COAST TUE/WED PER THE STORM PREDICTION CENTER.  
FURTHERMORE, HEAVY RAIN WILL INCREASE THE THREAT OF FLASH FLOODING  
ACROSS PORTIONS OF THE LOWER MISSISSIPPI, TENNESSEE, AND LOWER  
OHIO VALLEYS, WHERE HIGH RAIN RATES ARE FORECAST TO BE HIGHEST AND  
MOST SUSTAINED. THEREFORE, A SLIGHT RISK IS INDICATED TUESDAY IN  
THE EXPERIMENTAL WPC MEDIUM RANGE EXCESSIVE RAINFALL OUTLOOK.  
SOME ISOLATED FLASH FLOODING IS ALSO POSSIBLE WEDNESDAY FOR THE  
SOUTHERN/CENTRAL APPALACHIANS AND INTERIOR SOUTHEAST. SOME AREAS  
OF HEAVY RAIN ARE ALSO POSSIBLE ALONG THE EASTERN SEABOARD AHEAD  
OF THE COLD FRONT. ADDITIONALLY, SOME PRECIPITATION APPEARS  
LIKELY FROM THE NORTHERN PARTS OF THE PLAINS THROUGH THE  
NORTHEAST, WHICH COULD BE IN THE FORM OF SNOW. CURRENTLY THE  
HIGHEST PROBABILITIES FOR NOTABLE SNOW ARE IN THE UPPER GREAT  
LAKES REGION. SOME WINTRY PRECIPITATION SHOULD ALSO BE POSSIBLE  
ACROSS THE INTERIOR NORTHEAST THURSDAY MORNING AHEAD OF A WARM  
FRONT, FOLLOWED BY LIGHTER WINTRY MIX/SNOW LINGERING INTO NEXT  
WEEKEND. IN THE WEST, MAINLY DRY WEATHER IS EXPECTED, EXCEPT  
NORTHWESTERN WASHINGTON WITH THE PASSAGE OF A WAVE OF MOISTURE  
MIDWEEK FOLLOWED BY POSSIBLY THE ARRIVAL OF A MORE WIDESPREAD  
MOISTURE SURGE BY NEXT WEEKEND.  
 
THE STRONG UPPER RIDGE BUILDING INTO THE WEST WILL LEAD TO A BROAD  
AREA OF HIGHS 10-20F ABOVE NORMAL TUESDAY-SATURDAY WITH SLIGHTLY  
HIGHER LOCALIZED ANOMALIES POSSIBLE. THE BEST POTENTIAL TO REACH  
DAILY RECORD HIGHS WILL BE OVER CALIFORNIA DURING  
TUESDAY-THURSDAY. LEADING UPPER LEVEL TROUGHING SHOULD SUPPORT  
TEMPERATURES 10-20F BELOW AVERAGE ACROSS THE CENTRAL/SOUTHERN HIGH  
PLAINS TUESDAY AND WEDNESDAY. THE COOLER AIR SHOULD MODERATE  
CLOSER TO NORMAL BY THE LATTER PART OF NEXT WEEK AS IT PROGRESSES  
EASTWARD. AHEAD OF THE TROUGH AND COLD FRONTS, GENERALLY WARMER  
THAN NORMAL CONDITIONS ARE LIKELY ACROSS MUCH OF THE EASTERN THIRD  
OF THE U.S. FOR MUCH OF THE WEEK, TRANSITIONING TO NEAR NORMAL  
TEMPERATURES BY FRIDAY AND SATURDAY. ISOLATED RECORD HIGHS ARE  
POSSIBLE OVER PARTS OF FLORIDA TUESDAY-WEDNESDAY.  
 
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  
 
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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