858  
FXUS02 KWBC 121857  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
157 PM EST SAT FEB 12 2022  
 
VALID 12Z TUE FEB 15 2022 - 12Z SAT FEB 19 2022  
 
...MID-LATE WEEK SYSTEM TO BRING POTENTIAL FOR HEAVY RAIN AND  
SEVERE WEATHER FROM THE SOUTH-CENTRAL TO EAST-CENTRAL 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 A SHARP  
UPPER TROUGH LIKELY CENTERED FROM THE NORTHERN ROCKIES THROUGH  
CALIFORNIA AS OF EARLY TUESDAY. THIS FEATURE, POSSIBLY CONTAINING  
AN UPPER LOW FOR A BRIEF TIME, WILL TRACK EASTWARD THROUGH MIDWEEK  
AND THEN BECOME INCORPORATED INTO 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 INTO FRIDAY.  
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.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
LATEST MODELS AND ENSEMBLES HAVE BEEN SHOWING SOME INCREMENTAL  
ADJUSTMENTS FOR THE UPPER SYSTEM INITIALLY DROPPING INTO THE WEST  
AND ASSOCIATED SURFACE EVOLUTION THROUGH THE WEEK. TO START THE  
PERIOD, GUIDANCE IS KEEPING THE WESTERN TROUGH A LITTLE MORE OPEN  
AND BY EARLY DAY 4 WEDNESDAY GIVES MIXED SIGNALS FOR WHETHER THERE  
WILL BE A CLOSED LOW--THOUGH STILL WITH MAJORITY SUPPORT TO FAVOR  
SHOWING ONE IN A SINGLE DETERMINISTIC FORECAST. EITHER WAY THE  
RECENT TRENDS HAVE BEEN FOR A MORE OPEN FEATURE AS IT EJECTS INTO  
THE PLAINS, LEADING TO 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. LATEST CMC RUNS STRAY  
SOUTHWEST OF OTHER SOLUTIONS WITH THE WESTERN UPPER SYSTEM AND  
THEN SHEAR IT OUT MORE DRAMATICALLY FARTHER EAST, RESULTING IN A  
WEAKER SURFACE PATTERN. AN AVERAGE OF GFS/ECMWF/UKMET RUNS FROM  
THE 00Z/06Z CYCLES PROVIDED A MEASURED ADJUSTMENT FROM CONTINUITY.  
IT WILL BE INTERESTING TO SEE IF PERSISTENCE OF A WEAKER SCENARIO  
IN THE CMC FORESHADOWS ADDITIONAL WEAKENING/PROGRESSION IN OTHER  
SOLUTIONS, SUCH AS SEEN IN THE NEW 12Z ECMWF. 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 LATE IN THE PERIOD. CONFIDENCE IS CURRENTLY  
MINIMAL FOR SPECIFICS OF THIS FEATURE. HOWEVER THERE IS DECENT  
AGREEMENT ON AN UPSTREAM SHORTWAVE/COLD FRONT APPROACHING THE  
PACIFIC NORTHWEST LATER NEXT SATURDAY.  
 
PREFERENCES FOR THE SYSTEM OVER THE WEST AND CONTINUING EASTWARD  
FAVORED STARTING THE FORECAST WITH THE 06Z GFS/00Z ECMWF AND 00Z  
UKMET FOR ABOUT THE FIRST HALF OF THE PERIOD. THEN THE BLEND  
INCORPORATED SOME OF THE 06Z GEFS/00Z ECMWF MEANS BY DAYS 6-7  
FRIDAY-SATURDAY GIVEN DECREASING CONFIDENCE IN SOME DETAILS.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
UNDERNEATH THE UPPER LOW/TROUGH OVER THE WEST TUESDAY INTO  
WEDNESDAY, EXPECT LIGHT TO MODERATE PRECIPITATION IN THE FORM OF  
LOWER ELEVATION RAIN AND MOUNTAIN SNOW TO SPREAD FROM CALIFORNIA  
AND GREAT BASIN/NORTHERN ROCKIES INTO THE CENTRAL ROCKIES. SHOWERS  
AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD OVER THE CENTRAL  
U.S. BY 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 INTO THE SOUTHERN  
APPALACHIANS. 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, AND WINTRY WEATHER COULD BE  
WITHIN A FAIRLY NARROW BAND. STRONG WINDS MAY BE POSSIBLE IN THE  
GRADIENT BETWEEN THE SURFACE LOW AND HIGH PRESSURE TO THE  
NORTHWEST, AND THEN POSSIBLY ALONG PARTS OF THE EAST COAST WITHIN  
THE SOUTHERLY FLOW AHEAD OF THE SYSTEM. RECENT TRENDS TOWARD LOW  
PRESSURE BEING WEAKER AND FASTER, AT LEAST FROM THE PLAINS THROUGH  
OHIO VALLEY/GREAT LAKES, COULD TEMPER SNOWFALL AND WIND SPEEDS  
SOMEWHAT.  
 
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 A  
LITTLE LIGHT PRECIPITATION MAY REACH THE NORTHERN PACIFIC  
NORTHWEST/ROCKIES. 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 THROUGH THE WORKWEEK 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 PLAINS ON TUESDAY INTO THE  
MID-MISSISSIPPI AND OHIO VALLEYS (WHILE PERSISTING IN THE SOUTHERN  
PLAINS) ON WEDNESDAY, THEN INTO THE EASTERN SEABOARD ON THURSDAY.  
SOME LOWS IN THE EAST COULD CHALLENGE DAILY RECORDS FOR WARMTH IF  
THEY HOLD FOR THE CALENDAR DAY. ON THE BACKSIDE OF THE FRONT,  
TEMPERATURES SHOULD FLIP TO NEAR OR BELOW AVERAGE, FIRST OVER THE  
WEST AND SPREADING TO THE ROCKIES, PLAINS, AND MIDWEST 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.  
 
RAUSCH/TATE  
 
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  
 

 
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page