644  
FXUS02 KWBC 281900  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
159 PM EST FRI JAN 28 2022  
 
VALID 12Z MON JAN 31 2022 - 12Z FRI FEB 04 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
 
 
A WEAK SHORTWAVE MOVING THROUGH THE SOUTHERN PLAINS ON MONDAY  
SHOULD GENERATE ENHANCED RAINFALL ALONG/NORTH OF THE TEXAS GULF  
COAST, BEFORE SHEARING OUT PRETTY QUICKLY ON TUESDAY DUE TO A  
BUILDING RIDGE OVER THE WESTERN ATLANTIC. AFTER THIS, TROUGHING  
WILL DIG INTO THE WEST TUESDAY-WEDNESDAY AND SHIFT/EXPAND EASTWARD  
INTO THE CENTRAL U.S. THURSDAY. BY FRIDAY, BROAD LONGWAVE  
TROUGHING SHOULD COVER MUCH OF THE CONUS AS STRONG RIDGING BUILDS  
OVER THE EASTERN PACIFIC AND WESTERN ATLANTIC. THIS EVOLUTION IS  
EXPECTED TO BRING WIDESPREAD PRECIPITATION ALONG A LEADING FRONTAL  
BOUNDARY INTO MUCH OF THE EASTERN HALF OF THE COUNTRY MID-LATE  
NEXT WEEK, WITH POTENTIAL FOR NOTABLE 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 ARE PRETTY CONSISTENT WITH THE  
TRACK OF THE INITIAL COMPACT SOUTHERN STREAM UPPER LOW OVER TEXAS  
MONDAY AND INTO THE GULF EARLY TUESDAY BEFORE SHEARING OUT WITH  
SOMEWHAT VARIABLE TIMING. A MULTI-MODEL DETERMINISTIC BLEND WORKED  
WELL FOR THIS FEATURE. IN THE NORTHERN STREAM, A COUPLE OF  
SHORTWAVES MOVING ACROSS THE GREAT LAKES REGION TOWARD THE WESTERN  
ATLANTIC EARLY IN THE WORKWEEK SHOWED GOOD AGREEMENT IN THE 00Z  
AND 06Z GFS AND 00Z ECMWF, WITH SOME SLIGHTLY DIFFERENT SOLUTIONS  
IN THE 00Z CMC AND UKMET.  
 
THEN THERE IS GOOD CONSENSUS WITH ENERGY DIVING SOUTH THROUGH THE  
INTERMOUNTAIN WEST FOR THE FIRST HALF OF THE WORKWEEK, SERVING TO  
DEEPEN THE TROUGH IN THE WEST-CENTRAL U.S., BUT WITH LINGERING  
UNCERTAINTY ON THE EXACT MAGNITUDE--THE 00Z UKMET WAS DEEPER THAN  
OTHER GUIDANCE/MOST ENSEMBLE MEMBERS BY EARLY WEDNESDAY. THE TREND  
TOWARD LESS SEPARATION OF STREAMS WITHIN THE TROUGH HAS REMAINED  
FOR THE PAST COUPLE OF CYCLES, SO THERE IS A BUILDING CONSENSUS  
WITH THAT. THEN BY THURSDAY INTO FRIDAY, THERE ARE SOME ADDITIONAL  
DIFFERENCES WITH SHORTWAVE FEATURES WITHIN THE BROADER TROUGH.  
ENERGY MOVING THROUGH THE BASE OF THE TROUGH THURSDAY EXHIBITS  
SOME DIFFERENCES THAT ALSO AFFECT FRONTAL AND SURFACE LOW POSITION  
BY FRIDAY IN THE NORTHEAST, WHILE MODEL GUIDANCE ALSO VARIES WITH  
STRENGTH OF ENERGY POSSIBLY DIPPING THROUGH THE WESTERN SIDE OF  
THE TROUGH. IN GENERAL THE GFS RUNS HAVE BEEN STRONGER WITH THIS  
FEATURE (WITH THE EXCEPTION OF THE 06Z GFS) COMPARED TO ECMWF  
RUNS, BUT THE 12Z ECMWF CAME IN WITH A STRONGER SHORTWAVE THAN ITS  
PAST RUNS. SO THE RUN-TO-RUN INCONSISTENCIES AS WELL AS NOTABLE  
DIFFERENCES IN INDIVIDUAL ENSEMBLE MEMBERS SHOW THIS ASPECT IS  
STILL UNCERTAIN.  
 
THE WPC FORECAST USED A MULTI-MODEL DETERMINISTIC BLEND FAVORING  
THE GFS AND ECMWF EARLY IN THE PERIOD, GRADUALLY PHASING IN SOME  
PROPORTION OF THE 06Z GEFS AND 00Z EC ENSEMBLE MEANS TO ABOUT 40  
PERCENT BY THE END OF THE PERIOD TO MAINTAIN SOME DEFINITION OF  
SYSTEMS BUT SMOOTH INDIVIDUAL MODEL DIFFERENCES.  
 
   
..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. THE BEST POTENTIAL STILL APPEARS TO BE OVER EASTERN  
TEXAS, WITH SOME POTENTIAL FOR HEAVY RAINFALL FARTHER EAST ALONG  
THE GULF COAST DEPENDING ON THE EXACT TRACK OF THE MID-UPPER  
ENERGY. THE NORTHEASTERN PACIFIC UPPER TROUGH DIGGING INTO THE  
WEST MONDAY-TUESDAY WILL SPREAD LIGHT TO MODERATE AMOUNTS OF LOWER  
ELEVATION RAIN AND MOUNTAIN SNOW FROM THE PACIFIC NORTHWEST  
EASTWARD AND SOUTHEASTWARD INTO MUCH OF THE ROCKIES. 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 TO THE  
APPALACHIANS 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 CENTRAL PARTS OF THE PLAINS AND  
MISSISSIPPI VALLEY NORTHEASTWARD THROUGH THE GREAT LAKES AND INTO  
THE INTERIOR NORTHEAST. 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.  
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 10-20 DEGREES  
BELOW AVERAGE ARE POSSIBLE. LOCALLY HIGHER VALUES AS MUCH AS 25F  
BELOW NORMAL ARE POSSIBLE ACROSS THE NORTH-CENTRAL U.S. THE BELOW  
NORMAL TEMPS MAY 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.  
 
TATE/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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