897  
FXUS02 KWBC 290700  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
159 AM EST SAT JAN 29 2022  
 
VALID 12Z TUE FEB 01 2022 - 12Z SAT FEB 05 2022  
 
...NEXT WEEK TO BRING HEAVY PRECIPITATION TO THE CENTRAL AND  
EASTERN U.S., INCLUDING WINTER WEATHER FROM THE CENTRAL PLAINS TO  
GREAT LAKES AND INTERIOR NORTHEAST AROUND MIDWEEK...  
 
   
..OVERVIEW
 
 
UPPER LEVEL RIDGING OVER BOTH THE WESTERN ATLANTIC AND EAST  
PACIFIC WILL ALLOW FOR A SHORTWAVE TO DIG INTO THE WESTERN U.S.  
TUESDAY-WEDNESDAY, SHIFTING EAST INTO THE PLAINS ON THURSDAY.  
ANOTHER SHORTWAVE SHOULD DROP INTO THE BASE OF THE TROUGH ON  
THURSDAY ACROSS THE SOUTHWEST WHICH WILL HELP TO REINFORCE/AMPLIFY  
THE TROUGH AS IT TRACKS INTO THE MIDWEST/EAST FRIDAY AND SATURDAY.  
THIS EVOLUTION IS EXPECTED TO BRING WIDESPREAD PRECIPITATION ALONG  
AND AHEAD OF A LEADING FRONTAL BOUNDARY INTO MUCH OF THE EASTERN  
HALF OF THE COUNTRY MID-LATE NEXT WEEK, WITH INCREASING POTENTIAL  
FOR WINTRY WEATHER ON THE BACKSIDE OF THE SYSTEM.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
RECENT MODEL GUIDANCE REMAINS IN GENERALLY GOOD AGREEMENT FOR THE  
OVERALL LARGE SCALE PATTERN, BUT WITH CONTINUING UNCERTAINTY IN  
THE SMALLER SCALE DETAILS. MODELS REMAIN PRETTY CONSISTENT WITH  
THE TRACK OF THE INITIAL COMPACT SOUTHERN STREAM UPPER LOW OVER  
THE GULF ON TUESDAY BEFORE SHEARING OUT WITH SOMEWHAT VARIABLE  
TIMING AS UPPER RIDGING BUILDS OFF THE EAST COAST. MEANWHILE, IN  
THE NORTHERN STREAM, A SHORTWAVE MOVING ACROSS THE GREAT LAKES AND  
NORTHEAST EARLY IN THE WORKWEEK ALSO SHOWS GOOD AGREEMENT IN THE  
DETERMINISTIC MODELS.  
 
THERE CONTINUES TO BE INCREASING CONSENSUS WITH ENERGY DIVING  
SOUTH THROUGH THE INTERMOUNTAIN WEST TUESDAY-WEDNESDAY, SERVING TO  
DEEPEN THE TROUGH INTO THE CENTRAL U.S.. A TREND TOWARDS LESS  
SEPARATION OF STREAMS WITH THE TROUGH HAS REMAINED, BUT MODELS ARE  
SHOWING TIMING DIFFERENCES INTO THE SOUTHERN PLAINS/MIDWEST WHICH  
AFFECTS FRONTAL AND SURFACE LOW POSITION BY FRIDAY. THE ECMWF AND  
CMC ARE FASTER THAN THE GFS AND UKMET (THROUGH DAY 5 AT LEAST),  
BUT THE ENSEMBLE MEANS TEND TO FALL SOMEWHERE IN BETWEEN. THERE  
ALSO SEEMS TO BE A TREND TOWARDS A STRONGER SHORTWAVE DIVING INTO  
THE SOUTHWEST AROUND FRIDAY BUT WITH A LOT OF UNCERTAINTY BY  
SATURDAY/DAY 7 REGARDING STRENGTH AND TIMING, AS EXHIBITED BY THE  
LATEST ENSEMBLE SPAGHETTI PLOTS.  
 
THE WPC FORECAST FOR TONIGHT USED A PURELY MULTI-MODEL  
DETERMINISTIC BLEND FOR DAYS 3-5. AFTER THAT, INCREASED WEIGHTING  
OF THE GEFS/ECENS ENSEMBLE MEANS TO HELP MITIGATE SOME OF THE LATE  
PERIOD DIFFERENCES. GIVEN BETTER THAN AVERAGE AGREEMENT ON THE  
LARGE SCALE THOUGH, WAS STILL ABLE TO MAINTAIN 50 PERCENT OF THE  
DETERMINISTIC GFS/ECMWF (AND SMALLER PARTS CMC) THROUGH DAY  
7/SATURDAY. OVERALL, THIS MAINTAINED GOOD CONTINUITY WITH THE  
PREVIOUS WPC FORECAST FOR DAYS 3-6.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
SOME MODERATE RAIN MAY BE POSSIBLE ALONG THE CENTRAL GULF COAST ON  
TUESDAY ASSOCIATED WITH WEAKENING SOUTHERN STREAM ENERGY OUT OVER  
THE GULF AND INCREASING MOISTURE AHEAD OF THE NEXT SYSTEM INTO THE  
WEST. THE BIGGER THREAT DURING THE MEDIUM RANGE PERIOD THOUGH IS A  
DEVELOPING TROUGH OVER THE WEST AND INTO THE CENTRAL U.S. BY  
WEDNESDAY. INITIALLY ON TUESDAY, THIS FEATURE SHOULD SPREAD MAINLY  
LIGHT TO MODERATE LOWER ELEVATION RAIN AND MOUNTAIN SNOW ACROSS  
THE ROCKIES. THE FORECAST HOWEVER REMAINS ON TRACK FOR A  
SIGNIFICANT INCREASE OF COVERAGE AND INTENSITY OF PRECIPITATION  
OVER THE EAST-CENTRAL U.S. BY WEDNESDAY AND BEYOND AS THE UPPER  
TROUGH EMERGES FROM THE ROCKIES AND THE LEADING COLD FRONT  
INTERACTS WITH A STRONG LOW LEVEL FEED OF GULF MOISTURE. THE BEST  
CHANCE FOR HEAVIEST RAINFALL EXTENDS ACROSS THE LOWER HALF OF THE  
MISSISSIPPI VALLEY INTO PARTS OF THE OHIO/TENNESSEE VALLEYS TO THE  
APPALACHIANS AND THE EAST. THE PATTERN CERTAINLY FAVORS A HEAVY TO  
EXCESSIVE RAINFALL THREAT, BUT THE EXACT LOCATION OF WHERE THIS  
SETS UP ANY FLOODING/FLASH FLOODING IMPACTS REMAINS QUITE  
UNCERTAIN STILL. WINTRY WEATHER WILL BE POSSIBLE ON THE NORTHWEST  
SIDE OF THE MOISTURE SHIELD, WITH INCREASING POTENTIAL FOR  
MEANINGFUL SNOW FROM CENTRAL PARTS OF THE PLAINS AND MISSISSIPPI  
VALLEY NORTHEASTWARD THROUGH THE GREAT LAKES AND INTO THE INTERIOR  
NORTHEAST. WHILE HEAVY RAINFALL TO THE SOUTH SEEMS FAIRLY CERTAIN,  
THE DETAILS WITH THE WINTRY PRECIPITATION IN THE COLDER AIR MAY BE  
MORE DEPENDENT ON LOWER-CONFIDENCE DETAILS OF EJECTING SHORTWAVE  
ENERGY AND FRONTAL WAVES.  
 
ABOVE AVERAGE TEMPERATURES WILL SPREAD EASTWARD TUESDAY-THURSDAY  
ACROSS THE EASTERN THIRD OF THE COUNTRY WITH DAYTIME HIGHS AS MUCH  
AS 15-20 DEGREES ABOVE NORMAL ALONG THE EAST COAST ON FRIDAY. AT  
THE SAME TIME, ARCTIC HIGH PRESSURE DIVES INTO THE CENTRAL U.S.  
BEHIND THE COLD FRONT MIDWEEK, BRINGING CHILLY AND MUCH BELOW  
NORMAL TEMPERATURES ALL THE WAY FROM THE NORTHERN ROCKIES/HIGH  
PLAINS SOUTHWARD INTO TEXAS. WIDESPREAD DAYTIME HIGHS (AND  
SLIGHTLY LESS EXTREME OVERNIGHT LOWS) AS MUCH AS 10-25 DEGREES  
BELOW AVERAGE ARE POSSIBLE. THE BELOW NORMAL TEMPS MAY MODERATE  
SLIGHTLY AS THEY SHIFT EAST INTO THE OHIO VALLEY/GULF COAST STATES  
NEXT FRIDAY AND THE EAST ON SATURDAY. THE WEST COAST STATES SHOULD  
BE NEAR NORMAL THROUGH MUCH OF NEXT WEEK OWING TO AMPLIFIED  
RIDGING ACROSS THE EAST PACIFIC.  
 
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  
 
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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