665  
FXUS02 KWBC 130711  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
210 AM EST SUN FEB 13 2022  
 
VALID 12Z WED FEB 16 2022 - 12Z SUN FEB 20 2022  
 
...MID-LATE WEEK SYSTEM TO BRING POTENTIAL FOR HEAVY RAIN AND  
SEVERE WEATHER FROM THE SOUTH-CENTRAL TO EASTERN U.S. AND WINTRY  
WEATHER FROM THE MIDWEST THROUGH GREAT LAKES AND INTERIOR  
NORTHEAST...  
   
..OVERVIEW
 
 
THE DOMINANT FOCUS OF THE MEDIUM RANGE FORECAST WILL BE AN UPPER  
TROUGH/LOW LIKELY CENTERED NEAR THE FOUR CORNERS EARLY WEDNESDAY,  
WHICH WILL TRACK EASTWARD AND PHASE WITH A PLAINS/EAST-CENTRAL  
U.S. MEAN TROUGH. THIS EVOLUTION ALOFT WILL LEAD TO SURFACE  
CYCLOGENESIS AND STRONG FRONTAL SYSTEMS IN THE CENTRAL U.S.,  
DRAWING MOISTURE NORTHWARD FROM THE GULF OF MEXICO AND PRODUCING  
NOTABLE PRECIPITATION FROM THE PLAINS EASTWARD NEXT WEDNESDAY AND  
THURSDAY. EXPECT RAIN AND THUNDERSTORMS IN SOUTHERN AREAS, WHILE  
SNOW AND WINTRY WEATHER ARE LIKELY ON THE NORTHERN AND WESTERN  
SIDE OF THE PRECIPITATION SHIELD ACROSS THE CENTRAL ROCKIES/PLAINS  
AND THROUGH THE MIDWEST, GREAT LAKES, AND INTERIOR NORTHEAST. BY  
FRIDAY-SATURDAY EXPECT A WEAKER CLIPPER SYSTEM TRACKING NEAR THE  
CANADIAN BORDER TO BRING A COLD FRONT INTO THE NORTHERN TIER WHILE  
A STEADILY WEAKENING (BUT INITIALLY QUITE STRONG) EASTERN PACIFIC  
UPPER RIDGE DRIFTS TOWARD THE WEST COAST, BEFORE ADDITIONAL  
TROUGHING ENTERS THE PACIFIC NORTHWEST BY SUNDAY.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODEL GUIDANCE CONTINUES TO SHOW FAIRLY GOOD AGREEMENT WITH THE  
OVERALL PATTERN DESCRIBED ABOVE, BUT WITH DETAIL DIFFERENCES THAT  
COULD BE IMPACTFUL TO THE SENSIBLE WEATHER. THE BULK OF GUIDANCE  
STILL SHOWS EVIDENCE TO MAINTAIN THE CLOSED LOW WITHIN THE WESTERN  
U.S. TROUGH TO START THE PERIOD EARLY WEDNESDAY, THEN QUICKLY JOIN  
WITH NORTHERN STREAM TROUGHING IN THE CENTRAL U.S. BY THURSDAY.  
OVER THE PAST DAY OR SO, GUIDANCE HAS TRENDED TOWARD A SOMEWHAT  
WEAKER AND FASTER SURFACE SYSTEM FROM THE PLAINS THROUGH MIDWEST  
AND GREAT LAKES. LOW PRESSURE DOES EVENTUALLY STRENGTHEN FARTHER  
NORTHEASTWARD AS NORTHERN STREAM DYNAMICS INCREASINGLY INFLUENCE  
THE SYSTEM. THE 12Z CMC CONTINUED ITS POSITION SOUTHWEST OF OTHER  
SOLUTIONS WITH THE WESTERN UPPER SYSTEM AND THEN SHEAR IT OUT MORE  
DRAMATICALLY FARTHER EAST, RESULTING IN A WEAKER SURFACE PATTERN.  
THE NEWER 00Z CMC IS IN SOMEWHAT BETTER ALIGNMENT WITH ITS UPPER  
LEVEL PATTERN BUT ITS SURFACE LOW MAY BE DISPLACED SOUTH OF A  
PREFERRED POSITION. AN AVERAGE OF GFS/ECMWF/UKMET RUNS FROM THE  
12Z/18Z CYCLES ONCE AGAIN SERVED TO REFLECT THESE MODEL TRENDS  
TOWARD A SLIGHTLY FASTER FRONT AND INITIALLY WEAKER LOW BUT ALSO  
MAINTAIN A MEASURE OF CONTINUITY FROM THE PREVIOUS FORECAST.  
BEYOND THE EARLY PERIOD DETAIL DIFFERENCES, THE COMBINATION OF  
UPSTREAM ENERGY DIVING INTO/THROUGH THE WEST FROM WEDNESDAY ONWARD  
AND NORTHERN STREAM TROUGHING THAT REACHES THE PLAINS/MISSISSIPPI  
VALLEY STILL CONTRIBUTE TO SOME OF THE UNCERTAINTY IN FORECASTS OF  
THIS SYSTEM OVER THE COURSE OF THE PERIOD. LINGERING SOUTHERN TIER  
SHORTWAVE ENERGY, WITH FAIRLY LOW PREDICTABILITY FOR SPECIFICS,  
MAY HAVE AN EFFECT ON FRONTAL WAVINESS AND PRECIPITATION TOWARD  
THE END OF THE PERIOD.  
 
ELSEWHERE, CONTINUITY IS FAIRLY GOOD IN PRINCIPLE FOR THE SYSTEM  
FORECAST TO TRACK NEAR THE CANADIAN BORDER/UPPER GREAT LAKES  
AROUND FRIDAY-SATURDAY WHILE TYPICAL DIFFERENCES EXIST FOR PRECISE  
TIMING OF THE TRAILING FRONT. MODELS VARY FOR A WEAK AND  
SMALL-SCALE SHORTWAVE ROUNDING THE PACIFIC UPPER RIDGE AND THEN  
DROPPING INTO THE WEST BY LATE IN THE WEEK, WITH GFS RUNS  
STRONGEST AND ECMWF RUNS WEAKEST WITH THIS FEATURE, AND CONFIDENCE  
REMAINS MINIMAL WITH THE SPECIFICS. HOWEVER THERE IS DECENT  
AGREEMENT ON AN UPSTREAM SHORTWAVE/COLD FRONT APPROACHING THE  
PACIFIC NORTHWEST OVER THE WEEKEND.  
 
PREFERENCES FOR THE SYSTEM OVER THE WEST AND CONTINUING EASTWARD  
FAVORED STARTING THE FORECAST WITH THE 12Z/18Z GFS AND 12Z ECMWF  
AND UKMET FOR ABOUT THE FIRST HALF OF THE PERIOD. THEN THE BLEND  
INCORPORATED SOME OF THE 18Z GEFS/12Z ECMWF MEANS BY THE WEEKEND  
GIVEN DECREASING CONFIDENCE IN SOME DETAILS.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
SHOWERS AND THUNDERSTORMS WILL BECOME WIDESPREAD OVER THE CENTRAL  
U.S. ON WEDNESDAY INTO THURSDAY AS SURFACE LOW PRESSURE  
CONSOLIDATES IN THE HIGH PLAINS AND ADVECTS SUBSTANTIAL MOISTURE  
FROM THE GULF OF MEXICO NORTHWARD INTO THE PLAINS,  
MISSISSIPPI/TENNESSEE/OHIO VALLEYS, AND EVENTUALLY THE  
APPALACHIANS AND EASTERN SEABOARD. STRONG STORMS ARE POSSIBLE,  
WITH THE STORM PREDICTION CENTER OUTLOOK SHOWING SOME SEVERE  
THREAT FOR PARTS OF THE SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI  
AND TENNESSEE VALLEYS AND VICINITY ON WEDNESDAY AND THURSDAY.  
THERE COULD ALSO BE FLASH FLOODING CONCERNS WHERE HEAVY RAINFALL  
OCCURS, POSSIBLY IN SIMILAR REGIONS AND SPREADING TOWARD MUCH OF  
THE EASTERN SEABOARD ON THURSDAY AND THURSDAY NIGHT. CURRENT  
FORECASTS SHOW THE SOUTHERN APPALACHIANS COULD SEE PARTICULARLY  
HIGH RAINFALL TOTALS GIVEN TERRAIN ENHANCEMENT THERE. CONTINUE TO  
MONITOR FORECASTS AS UNCERTAIN DETAILS OF THESE POTENTIAL THREATS  
BECOME BETTER REFINED. AT THE SAME TIME, EXPECT A BAND OF SNOW IN  
THE COLDER AIR ON THE NORTHWESTERN PERIPHERY OF THE SYSTEM. THE  
BEST POTENTIAL FOR MEANINGFUL ACCUMULATIONS CURRENTLY EXTENDS FROM  
CENTRAL PARTS OF THE PLAINS AND MIDWEST/MIDDLE MISSISSIPPI VALLEY  
INTO THE GREAT LAKES REGION AND INTERIOR NEW ENGLAND, WHILE MIXED  
PRECIPITATION/ICE CANNOT BE RULED OUT IN THE TRANSITION ZONE  
BETWEEN THE SNOW AND RAIN. TOTALS/LOCATION OF ANY SNOW WILL BE  
VERY SENSITIVE TO PRECISE STRENGTH AND TRACK OF THE SYSTEM GIVEN  
THAT WINTRY WEATHER COULD BE WITHIN A FAIRLY NARROW BAND, AND A  
FASTER FORECAST LOW/FRONT TRACK MAY TEMPER SNOWFALL AMOUNTS. GUSTY  
WINDS ARE POSSIBLE WITH THE SYSTEM AS WELL, AND AT THIS POINT  
APPEAR MOST LIKELY NEAR THE NORTHEAST COAST ON THURSDAY NIGHT IN  
STRONG SOUTHERLY FLOW AHEAD OF THE QUICKLY STRENGTHENING SURFACE  
LOW.  
 
DRY CONDITIONS SHOULD PREVAIL OVER MUCH OF THE LOWER 48 BEHIND  
THIS SYSTEM. BY FRIDAY OR SATURDAY THE SYSTEM ALONG THE CANADIAN  
BORDER MAY BRING SOME SNOW INTO THE UPPER GREAT LAKES WHILE LIGHT  
PRECIPITATION MAY REACH THE NORTHERN PACIFIC NORTHWEST/ROCKIES BY  
FRIDAY, WHICH COULD INCREASE IN AMOUNTS BY SATURDAY. SOME MOISTURE  
MAY LINGER OVER THE FAR SOUTHEAST/FLORIDA BUT WITH LOW CONFIDENCE  
IN COVERAGE AND INTENSITY OF RAINFALL AT THIS TIME.  
 
THE CHANGE AND PROGRESSION OF THE OVERALL PATTERN WILL BE EVIDENT  
IN TEMPERATURES OVER THE COURSE OF NEXT WEEK, AS WARMER THAN  
AVERAGE TEMPERATURES PUSH EASTWARD AHEAD OF THE TROUGH/FRONTAL  
SYSTEM AND COOLER TEMPERATURES SPREAD BEHIND THE COLD FRONT. HIGHS  
OF 10-20F ABOVE AVERAGE AND LOWS 15-30F ABOVE NORMAL WILL BE  
SHUNTED FROM THE SOUTHERN HALF OF THE PLAINS INTO THE MISSISSIPPI  
AND OHIO/TENNESSEE VALLEYS WEDNESDAY INTO THE EASTERN SEABOARD ON  
THURSDAY. DAILY RECORDS COULD BE SET FOR SOME LOCATIONS,  
ESPECIALLY FOR WARM LOWS IN THE EAST ON THURSDAY, WHILE A FEW  
RECORD HIGH MAXIMA COULD BE CHALLENGED AS WELL. ON THE BACKSIDE OF  
THE FRONT, TEMPERATURES SHOULD FLIP TO NEAR OR BELOW AVERAGE,  
SHOWN IN THE GREAT BASIN/ROCKIES AND NORTH-CENTRAL U.S. ON  
WEDNESDAY AND THURSDAY BEFORE TRACKING INTO THE EASTERN THIRD OF  
THE COUNTRY FOR THE LATTER PART OF THE WEEK WHILE MODERATING. BEST  
POTENTIAL FOR TEMPERATURES 10-20F BELOW AVERAGE WILL BE OVER THE  
SOUTHERN HALF OF THE ROCKIES/HIGH PLAINS AND UPPER MIDWEST INTO  
THE GREAT LAKES. AN INCREASING PORTION OF THE WEST AND EVENTUALLY  
THE PLAINS SHOULD WARM UP TO ABOVE AVERAGE ONCE AGAIN BY THE END  
OF THE WEEK. PARTS OF THE GREAT BASIN AND VICINITY COULD SEE HIGHS  
AT LEAST 10F ABOVE NORMAL, WHILE CENTRAL PARTS OF THE PLAINS COULD  
EVEN REACH 20F ABOVE AVERAGE WITH TEMPERATURES IN THE 60S BY  
SUNDAY.  
 
TATE/RAUSCH  
 
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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