522  
FXUS02 KWBC 181857  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
157 PM EST FRI FEB 18 2022  
 
VALID 12Z MON FEB 21 2022 - 12Z FRI FEB 25 2022  
 
...HEAVY TO EXCESSIVE RAIN THREAT FROM THE LOWER  
MISSISSIPPI/TENNESSEE VALLEY TO THE MID-ATLANTIC MONDAY-FRIDAY...  
 
...HEAVY SNOW/ICE THREATS ACROSS FROM NORTHERN PLAINS TO NORTHERN  
MAINE MONDAY-TUESDAY AND SOUTHERN PLAINS TO NORTHEAST  
WEDNESDAY-FRIDAY...  
 
   
..PATTERN OVERVIEW
 
 
A VERY ACTIVE WEATHER PATTERN IS EXPECTED TO DEVELOP BY EARLY NEXT  
WEEK AS AN UPPER LEVEL TROUGH DIGS ACROSS THE WESTERN U.S. WITH  
EJECTING ENERGIES AND INDUCED FRONTAL WAVES PROGRESSING  
DOWNSTREAM. THE UPPER TROUGH SHOULD SHIFT EASTWARD INTO THE  
CENTRAL PLAINS AND MIDWEST BY LATER NEXT WEEK AS AMPLIFIED RIDGING  
BUILDS OVER THE EAST PACIFIC AND WEST COAST. THIS VERY AMPLIFIED  
PATTERN RESULTS IN A RENEWED HEAVY RAIN AND FLOODING THREAT FROM  
ROUGHLY THE LOWER MISSISSIPPI/TENNESSEE VALLEY TO THE MID-ATLANTIC  
THROUGH MOST OF NEXT WEEK, WITH A DOUBLE DOSE OF WINTER STORM  
POTENTIAL -- FIRST ACROSS THE NORTHERN TIER TO FAR NORTHERN MAINE  
MONDAY AND TUESDAY, AND AGAIN FROM THE SOUTHERN PLAINS TO THE  
NORTHEAST THE SECOND HALF OF THE WEEK.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODELS AND ENSEMBLES CONTINUE TO SHOW VERY GOOD AGREEMENT ON THE  
OVERALL LARGE SCALE PATTERN DESCRIBED ABOVE THROUGH MOST OF THE  
PERIOD. THE AMPLIFYING TROUGH DURING THE EARLY PART OF NEXT WEEK  
OVER THE WEST IS SHOWING BETTER AGREEMENT IN TERMS OF TIMING  
COMPARED TO PREVIOUS DAYS, THOUGH TIMING BECOMES A LITTLE MORE  
UNCERTAIN LATER IN THE WEEK AS THE SHORTWAVE ENERGY SLIDES INTO  
THE CENTRAL PLAINS AND THE MIDWEST NEXT THURSDAY-FRIDAY. DESPITE  
ABOVE AVERAGE LARGE SCALE AGREEMENT, THE LATEST GUIDANCE CONTINUES  
TO OFFER PLENTY OF UNCERTAINTY IN THE DETAILS, WHICH WILL HAVE  
MORE SIGNIFICANT IMPACTS TO HEAVY SNOW/RAINFALL POTENTIAL ACROSS  
MUCH OF THE EASTERN HALF OF THE NATION. NOTHING NOTABLE STANDS OUT  
AT THIS TIME, AS MOST OF THESE DIFFERENCES ARE THE TYPICAL  
EXTENDED RANGE MODEL RUN TO RUN VARIATIONS ANYWAYS. BY LATER NEXT  
WEEK, THERE'S INDICATIONS AN AMPLIFIED RIDGE SHOULD BE LOCATED  
OVER THE EASTERN PACIFIC, AND POSSIBLY INTO PARTS OF THE WEST, BUT  
QUITE A BIT OF DISAGREEMENT ON INDIVIDUAL SYSTEMS ROUNDING THE  
TOP/EASTERN PART OF THE RIDGE INTO WESTERN CANADA AND THE  
NORTHWEST U.S..  
 
WPCS BLEND FOR TODAY USED A MAJORITY DETERMINISTIC MODEL BLEND FOR  
DAYS 3-5. AFTER THIS, INCREASED THE ENSEMBLE MEANS TO HELP  
MITIGATE THE SMALLER SCALE, HARDER TO RESOLVE, DETAIL DIFFERENCES.  
THIS APPROACH MAINTAINS GOOD CONTINUITY WITH THE OVERNIGHT WPC  
PACKAGE AS WELL.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
MODERATE TO HEAVY MOUNTAIN SNOWS ARE LIKELY TO FOCUS EARLY TO MID  
NEXT WEEK ACROSS THE COOLING WEST/ROCKIES AS POTENT TROUGH  
ENERGIES DIG INTO AN AMPLIFIED WESTERN U.S. UPPER TROUGH POSITION.  
A WAVY FRONT ON THE LEADING EDGE OF A COLD SURGE SET TO DIG INTO  
THE CENTRAL U.S. EARLY-MID NEXT WEEK WILL HAVE UPPER SUPPORT TO  
FAVOR A SWATH OF HEAVY SNOW FROM THE NORTHERN PLAINS/UPPER MIDWEST  
TO NORTHERN MAINE NEXT MONDAY-TUESDAY WITH SOME ICE ACCUMULATIONS  
POSSIBLE ALONG THE SOUTHERN EDGE. MEANWHILE, AMPLE UPPER ENERGIES  
WORKING DOWNSTREAM FROM THE WEST NEXT WEEK WILL ALSO ACT TO INDUCE  
WAVES ALONG A LEAD FRONT AND TAP DEEPENING MOISTURE FROM THE GULF  
OF MEXICO. THIS IS EXPECTED TO FUEL A HEAVY RAIN AND FLOOD THREAT  
FROM THE LOWER MISSISSIPPI/TENNESSEE VALLEYS TO THE MID-ATLANTIC  
STARTING EARLY NEXT WEEK ALONG WITH POTENTIAL FOR RE-DEVELOPMENT  
ALONG THE WAVY/SLOWED TRAILING FRONT LATER NEXT WEEK. THIS SECOND  
WAVE MAY ALSO SUPPORT A HEAVY SNOW/ICE THREAT FROM PARTS OF THE  
SOUTHERN PLAINS AND MID-MISSISSIPPI/OHIO VALLEYS TO A COLD AIR  
DAMMED NORTHEAST WEDNESDAY-FRIDAY. GIVEN DETAIL UNCERTAINTIES IN  
THE GUIDANCE, CONFIDENCE ON EXACT SNOW/ICE AMOUNTS AND LOCATIONS  
REMAINS VERY LOW AT THESE LONGER LEAD TIMES, BUT THE POTENTIAL IS  
THERE AND THE PATTERN CERTAINTLY SUPPORTS A THREAT SOMEWHERE.  
 
ARCTIC HIGH PRESSURE SURGING SOUTHWARD INTO THE CENTRAL U.S.  
DURING THE FIRST HALF OF NEXT WEEK WILL SUPPORT MUCH BELOW  
TEMPERATURES FROM THE NORTHWEST INTO MUCH OF THE CENTRAL U.S. AS  
FAR SOUTH AS TEXAS. ESPECIALLY FROM THE NORTHERN HIGH PLAINS TO  
THE NORTHERN/CENTRAL PLAINS, DAYTIME HIGHS AND OVERNIGHT LOWS  
COULD BE 30-40 BELOW NORMAL, WHICH COULD APPROACH TO EXCEED RECORD  
LOW MINS AND MAX VALUES. DAYTIME HIGHS ACROSS THE NORTHERN PART OF  
THIS REGION COULD STRUGGLE TO GET ABOVE 0F MONDAY AND TUESDAY.  
THIS COLD SHOULD MODERATE SOMEWHAT BY LATER NEXT WEEK AND SPREAD  
EASTWARD INTO THE MISSISSIPPI VALLEY AND PARTS OF THE MIDWEST.  
MEANWHILE, MUCH ABOVE NORMAL TEMPERATURES ARE EXPECTED ACROSS THE  
SOUTH AND EAST EARLY IN THE PERIOD (WITH SOME RECORDS POSSIBLE,  
ESPECIALLY OVERNIGHT MINS) AS UPPER LEVEL RIDGING BUILDS OVER THE  
REGION. TEMPERATURES SHOULD MODERATE BACK TO NORMAL FOR THE  
NORTHEAST NEXT THURSDAY-FRIDAY, BUT REMAIN ABOVE NORMAL FOR THE  
SOUTHEAST.  
 
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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