198  
FXUS02 KWBC 280702  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
202 AM EST FRI JAN 28 2022  
 
VALID 12Z MON JAN 31 2022 - 12Z FRI FEB 04 2022  
   
..OVERVIEW
 
 
A WEAK SHORTWAVE MOVING THROUGH THE SOUTHERN PLAINS ON MONDAY  
SHOULD SHEAR OUT PRETTY QUICKLY AS IT MOVES OUT OF THE PLAINS  
TUESDAY-WEDNESDAY DUE TO A BUILDING RIDGE OVER THE WESTERN  
ATLANTIC. THIS SHORTWAVE SHOULD AT LEAST GENERATE ENHANCED  
RAINFALL ALONG/NORTH OF THE GULF COAST ON MONDAY. AFTER THIS,  
ANOTHER SHORTWAVE IS FORECAST TO AMPLIFY OUT OF THE WEST, SENDING  
AN AMPLIFIED AND ELONGATED TROUGH INTO THE CENTRAL U.S. BY  
THURSDAY. BY FRIDAY, BROAD LONGWAVE TROUGHING SHOULD COVER MUCH OF  
THE CONUS AS STRONG RIDGING BUILDS OVER THE EAST PACIFIC AND  
WESTERN ATLANTIC. THIS EVOLUTION IS EXPECTED TO BRING WIDESPREAD  
PRECIPITATION ALONG A LEADING FRONTAL BOUNDARY INTO THE EASTERN  
THIRD OF THE COUNTRY MID-LATE NEXT WEEK, WITH POTENTIAL FOR WINTRY  
WEATHER ON THE BACKSIDE OF THE SYSTEM.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
FOR THE MOST PART, THE GUIDANCE SHOWS PRETTY GOOD AGREEMENT ON THE  
OVERALL LARGE SCALE PATTERN, BUT PLENTY OF CONTINUED UNCERTAINTY  
IN THE DETAILS. THE 27/12Z UKMET REMAINED A NOTABLE OUTLIER FOR  
THE INITIAL SHORTWAVE THROUGH THE SOUTHERN PLAINS/GULF COAST ON  
MONDAY, BUT THE 28/00Z RUN TRENDED A LITTLE SLOWER AND MORE IN  
LINE WITH THE REST OF THE GUIDANCE. FOR THE NEXT SYSTEM DIGGING  
INTO THE WESTERN/CENTRAL U.S. TUESDAY-THURSDAY, THE OPERATIONAL  
MODELS SEEM TO BE TRENDING TOWARDS LESS SEPARATION OF  
NORTHERN/SOUTHERN STREAM ENERGY COMPARED TO PREVIOUS RUNS, THOUGH  
THE UKMET AGAIN IS PROBLEMATIC WITH MAINTAINING MORE SEPARATION  
BETWEEN STREAMS. FOR THE FIRST HALF OF THE PERIOD, WPC LEANED  
TOWARDS A NON-UKMET DETERMINISTIC MODEL RUN CONSENSUS.  
 
LARGER DIFFERENCES ACROSS THE BOARD BEGIN TO ARISE DURING THE  
SECOND HALF OF THE PERIOD. FIRST CONCERNING ENERGY LIFTING TOWARDS  
THE GREAT LAKES/NORTHEAST WHERE THE GFS IS NOTICEABLY FASTER THAN  
THE ECMWF, WHICH AFFECTS DEEPENING LOW PRESSURE INTO THE LOWER  
GREAT LAKES/NORTHEAST ON FRIDAY. OUT WEST, UNCERTAINTIES REMAIN  
WITH STRENGTH OF UPSTREAM ENERGY DROPPING INTO THE MEAN TROUGH ON  
THURSDAY. THE PAST FEW RUNS OF THE ECMWF HAVE BEEN CONSISTENTLY  
MUCH WEAKER AND FASTER WITH THE ENERGY AS IT ROUNDS OUT THE BASE  
OF THE TROUGH BY FRIDAY. THE GFS HAD BEEN CONSISTENTLY MORE  
AMPLIFIED/SLOWER THOUGH THE 27/18Z RUN LOOKED A LOT LIKE THE  
ECMWF, AND THE 00Z RUN AGAIN A TAD MORE AMPLIFIED THAN THE  
PREVIOUS RUN. THE CMC IS ALSO STRONGER/SLOWER. A LOOK AT  
INDIVIDUAL ENSEMBLE MEMBERS AND THE MEANS, SUGGEST A MORE  
AMPLIFIED SOLUTION IS POSSIBLE (MORE SO EVIDENT IN THE GEFS THAN  
THE ECENS MEMBERS). GIVEN THE LINGERING UNCERTAINTIES BOTH WITH  
THE NORTHEAST ENERGY AND THE WESTERN ENERGY, THE WPC FORECAST FOR  
DAYS 6 AND 7 TRENDED TOWARDS THE MEANS, BUT CONTINUED ABOUT 50  
PERCENT CONTRIBUTION FROM THE LATEST AVAILABLE GFS/ECMWF FOR SOME  
ADDED DEFINITION TO INDIVIDUAL SYSTEMS.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
THE UPPER SHORTWAVE/LOW INTO THE SOUTHERN PLAINS BY MONDAY WILL  
BRING A THREAT FOR LOCALLY MODERATE TO HEAVY RAINFALL FROM EASTERN  
TEXAS ACROSS PARTS OF THE GULF COAST REGION DURING THE FIRST HALF  
OF NEXT WEEK. BEST POTENTIAL AT THIS TIME APPEARS TO BE OVER  
EASTERN TEXAS WITH LOWER CONFIDENCE IN DETAILS FARTHER EAST. SOME  
ASPECTS OF THIS EVENT MAY HINGE ON SMALL-SCALE DETAILS NOT EASILY  
RESOLVED VERY FAR IN ADVANCE. THE NORTHEASTERN PACIFIC UPPER  
TROUGH DIGGING INTO THE WEST MONDAY-TUESDAY WILL SPREAD MODERATE  
AMOUNTS OF RAIN AND MOUNTAIN SNOW FROM THE PACIFIC NORTHWEST  
EASTWARD AND SOUTHEASTWARD INTO MUCH OF THE ROCKIES. HIGHEST  
TOTALS ARE LIKELY TO BE IN THE PACIFIC NORTHWEST BUT SHOULD NOT BE  
TOO EXTREME. IN GENERAL, THE FORECAST REMAINS ON TRACK FOR A  
SIGNIFICANT INCREASE OF COVERAGE AND INTENSITY OF PRECIPITATION  
OVER THE EAST-CENTRAL U.S. THE SECOND HALF OF THE WEEK AS THE  
UPPER TROUGH EMERGES FROM THE ROCKIES AND THE LEADING COLD FRONT  
INTERACTS WITH A STRONG LOW LEVEL FEED OF GULF MOISTURE. AT THIS  
TIME THE BEST CHANCE FOR HEAVIEST RAINFALL EXTENDS ACROSS THE  
LOWER HALF OF THE MISSISSIPPI VALLEY INTO PARTS OF THE  
OHIO/TENNESSEE VALLEYS AND THE EAST. WINTRY WEATHER WILL BE  
POSSIBLE ON THE NORTHWEST SIDE OF THE MOISTURE SHIELD, WITH AT  
LEAST SOME POTENTIAL FOR MEANINGFUL SNOW FROM THE  
CENTRAL/SOUTH-CENTRAL PLAINS NORTHEASTWARD THROUGH THE GREAT  
LAKES. WHILE CONFIDENCE IN A HEAVY RAIN AREA APPEARS BETTER THAN  
AVERAGE, 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 INITIALLY OVER THE PLAINS ON MONDAY  
SHOULD SPREAD EASTWARD TUESDAY-THURSDAY AS UPPER RIDGING BUILDS  
IN. BEHIND THIS, ARCTIC HIGH PRESSURE DIVES INTO THE CENTRAL U.S.  
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 10-20 DEGREES BELOW NORMAL ARE POSSIBLE. LOCALLY  
HIGHER VALUES AS MUCH AS 25 BELOW NORMAL ARE POSSIBLE ACROSS THE  
FAR NORTHERN PLAINS. THE BELOW NORMAL TEMPS SHOULD MODERATE  
SLIGHTLY AS THEY SHIFT EAST INTO THE OHIO VALLEY/GULF COAST STATES  
NEXT FRIDAY. MUCH OF 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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