598  
FXUS02 KWBC 120706  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
205 AM 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 ON A  
POTENT UPPER LOW/TROUGH LIKELY CENTERED OVER NORTHERN  
CALIFORNIA/NEVADA TO BEGIN THE PERIOD TUESDAY, WHICH WILL TRACK  
EASTWARD AS THE WEEK PROGRESSES AND BECOME INCORPORATED INTO A  
PLAINS/EAST-CENTRAL U.S. MEAN TROUGH BY THE LATTER HALF OF THE  
WEEK. 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.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
FOR THE MOST PART, RECENT GUIDANCE REMAINS MORE AGREEABLE AND  
CONSISTENT THAN AVERAGE FOR THE MEDIUM RANGE PERIOD, ESPECIALLY  
FOR THE EARLY PART OF THE FORECAST. CONSENSUS HAS BEEN STEADY IN  
SHOWING THE UPPER LOW MOVING SOUTHEASTWARD OVER THE SOUTHWEST  
QUADRANT OF THE U.S. TUESDAY AND WEDNESDAY, WHILE DOWNSTREAM, LOW  
AMPLITUDE RIDGING BROADENS AND SHIFTS FROM THE CENTRAL TO EASTERN  
U.S. THE CMC WAS THE MAIN OUTLIER AMONG THE DETERMINISTIC GUIDANCE  
FOR THE 12/18Z CYCLE, WITH A WEAKER AND SLOWER UPPER LOW SYSTEM  
INDICATED BY WEDNESDAY THAT THEN AFFECTS ITS FORECAST DOWNSTREAM  
FOR THE LATTER PART OF THE WEEK. THIS HAS PERSISTED IN THE NEW 00Z  
CYCLE FOR THE CMC; IT MAY BE NOTABLE THAT THE NEW 00Z ECMWF SHOWS  
A BIT OF A PULL TO THE SOUTHWEST WITH THE CENTER OF THE UPPER LOW  
EARLY WEDNESDAY AS WELL, BUT NOT TO THE EXTENT OF THE CMC RUNS.  
BUT FOR THE EARLY PART OF THE WPC FORECAST, A BLEND OF THE 12/18Z  
GFS, 12Z ECMWF, AND 12Z UKMET REPRESENTED THE PREVAILING THEMES OF  
THE FORECAST WELL.  
 
UNCERTAINTY AND GUIDANCE SPREAD/RUN-TO-RUN VARIABILITY INCREASE  
SOMEWHAT DURING THE LATTER HALF OF THE PERIOD. CONTRIBUTORS TO THE  
DIFFERENCES INCLUDE UPSTREAM SHORTWAVE ENERGY FORECAST TO DROP  
INTO AND THROUGH THE WEST DURING MID-LATE WEEK AS WELL AS  
IMPORTANT SPECIFICS OF NORTHERN STREAM FLOW THAT MAY INTERACT WITH  
THE LEADING UPPER LOW AS IT EJECTS BEYOND THE ROCKIES/PLAINS, WITH  
SOME PHASING DIFFERENCES. THESE ISSUES WILL AFFECT THE TIMING,  
STRENGTH, AND TRACK OF LOW PRESSURE AS IT PROGRESSES FROM NEAR THE  
SOUTH-CENTRAL PLAINS NORTHEASTWARD AFTER MIDWEEK. HOWEVER, ECMWF  
AND GFS RUNS HAVE MATCHED FAIRLY WELL PARTICULARLY IN THE UPPER  
LEVELS CONSIDERING IT IS A DAY 5-7 FORECAST. 12/18Z GFS RUNS WERE  
A BIT NORTHWEST OF THE PREFERRED SOLUTION OF THE ECMWF AND  
ENSEMBLE MEANS WITH THE SURFACE LOW TRACK THURSDAY-FRIDAY, BUT THE  
00Z RUN APPEARS TO HAVE COME INTO BETTER AGREEMENT WITH THE LOW  
TRACK. INCLUDING SOME GEFS AND EC ENSEMBLE MEAN INPUT BY DAYS 6-7  
FRIDAY-SATURDAY ACCOUNTED FOR THE GRADUAL INCREASE OF UNCERTAINTY  
AND PROVIDED GOOD CONTINUITY FROM THE PREVIOUS FORECAST, WITH  
PERHAPS JUST A SLIGHTLY FASTER TRACK OF THE MAIN COLD FRONT AND  
PRECIPITATION FORECAST AND A SLIGHTLY STRONGER LOW INDICATED OVER  
THE NORTHEAST EARLY FRIDAY.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
UNDERNEATH THE UPPER LOW/TROUGH OVER THE WEST EARLY IN THE WEEK,  
SOME LIGHT TO MODERATE PRECIPITATION IN THE FORM OF LOWER  
ELEVATION RAIN AND MOUNTAIN SNOW IS EXPECTED FOR CALIFORNIA INTO  
THE GREAT BASIN AND INTO THE NORTHERN ROCKIES, INCREASING IN THE  
CENTRAL ROCKIES ON WEDNESDAY. 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  
INTO THE MIDDLE MISSISSIPPI VALLEY AND MIDWEST/GREAT LAKES REGION  
INTO 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. 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 STORM.  
 
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.  
ON THE BACKSIDE OF THE FRONT, TEMPERATURES SHOULD FLIP TO NEAR TO  
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. PARTS OF THE WEST AND INTO THE PLAINS ARE  
EXPECTED TO WARM UP ABOVE AVERAGE ONCE AGAIN BY THE END OF THE  
WEEK.  
 
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  
 

 
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page