920  
FXUS02 KWBC 162030  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
328 PM EST WED FEB 16 2022  
 
VALID 12Z SAT FEB 19 2022 - 12Z WED FEB 23 2022  
 
...DEVELOPING HEAVY RAINFALL THREAT ACROSS PORTIONS OF THE SOUTH  
EARLY NEXT WEEK...  
 
   
..OVERVIEW
 
 
THE MEDIUM RANGE PERIOD WILL BEGIN SATURDAY WITH GENERALLY QUIET  
WEATHER, BESIDES A CLIPPER SYSTEM BRINGING SNOW TO THE GREAT LAKES  
REGION. THEN AS NEXT WEEK BEGINS, TROUGHING IS FORECAST TO DEVELOP  
IN THE WEST AND SLOWLY TRACK EASTWARD ALONG WITH A STRONG FRONTAL  
SYSTEM. PRECIPITATION CHANCES SHOULD INCREASE IN THE WEST WITH  
THIS PATTERN AND SPREAD INTO THE CENTRAL U.S. ONCE AGAIN BY NEXT  
MONDAY THROUGH WEDNESDAY, WITH THE POSSIBILITY OF NORTHERN TIER  
SNOW AND SOUTHERN U.S. RAIN.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
RECENT MODEL GUIDANCE SHOWS GOOD AGREEMENT OVERALL WITH THE LARGE  
SCALE PATTERN THROUGH THE MIDDLE OF NEXT WEEK, THOUGH PLENTY OF  
LINGERING UNCERTAINTY IN THE SMALLER SCALE DETAILS. TO START THE  
PERIOD, THE SURFACE LOW/CLIPPER OVER THE GREAT LAKES AND  
UPPER-LEVEL ENERGY SUPPORTING IT CONTINUE TO HAVE GOOD CONSENSUS  
AMONG RECENT 00Z/06Z MODELS. A COMPACT CLOSED UPPER LOW TRACKING  
SOUTH ALONG THE CALIFORNIA COAST AHEAD OF THE MAIN LARGER SCALE  
TROUGH, AND WEAKENING AS IT MOVES ACROSS NORTHERN MEXICO, ALSO HAS  
SHOWN MUCH BETTER AGREEMENT IN RECENT CYCLES, INCLUDING THE GFS  
WHICH HAD BEEN A BIT OF AN OUTLIER THE PAST FEW CYCLES.  
 
THEN, THERE REMAINS GOOD LARGE SCALE AGREEMENT FOR ENERGY TO SPILL  
INTO THE WEST EAST OF AN AMPLIFIED EASTERN PACIFIC RIDGE BY NEXT  
SUNDAY-MONDAY. THIS SHOULD AMPLIFY EARLY NEXT WEEK AND SHIFT  
SLOWLY EASTWARD AS FLOW ACROSS THE CENTRAL AND EASTERN U.S. SHIFTS  
MORE ZONAL AND THEN RIDGING. THE 00Z CMC (AND TO SOME EXTENT THE  
06Z GFS) ARE STRONGER THAN THE ECMWF SHOWING A CLOSED LOW OVER THE  
WEST NEXT TUESDAY. BY TUESDAY-WEDNESDAY THOUGH, THE CMC IS VERY  
NOTABLY FASTER/FARTHER SOUTH WITH THE ENERGY AND THUS WAS NOT  
INCLUDED IN THE BLEND PAST DAY 5. THE ECMWF HAS CONSISTENTLY BEEN  
A LITTLE SLOWER/LESS AMPLIFIED WITH THE TROUGH, THOUGH THE  
ENSEMBLE SPREAD IS LARGE REGARDING THE EXACT DETAILS/TIMING OF  
EMBEDDED ENERGIES WITHIN THE MAIN TROUGH.  
 
THE WPC BLEND USED A MULTI DETERMINISTIC MODEL BLEND OF THE  
00Z/06Z GUIDANCE FOR DAYS 3 AND 4. AFTER THAT, INCREASED THE  
ENSEMBLE MEAN CONTRIBUTION (IN FAVOR OF THE CMC) TO HELP MITIGATE  
THE LATE PERIOD DETAIL DIFFERENCES. THE RESULTED IN SOME MINOR  
ADJUSTMENTS TO THE LEADING COLD FRONT INTO THE MIDWEST/EASTERN  
U.S. AT THE END OF THE PERIOD COMPARED TO OUR CONTINUITY, BUT ON  
AN OVERALL SCALE, TODAYS WPC FORECAST DOES MAINTAIN GOOD  
CONTINUITY IN TERMS OF THE MESSAGING FROM THE OVERNIGHT PACKAGE.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
LINGERING SNOW IS FORECAST ON SATURDAY ACROSS THE GREAT LAKES  
REGION WITH THE CLIPPER SYSTEM, WITH GENERALLY LIGHT TO PERHAPS  
LOCALLY MODERATE AMOUNTS. MAINLY DRY CONDITIONS ARE EXPECTED  
ELSEWHERE ON SATURDAY OTHER THAN A FEW SHOWERS POSSIBLE IN  
FLORIDA, EXCEPT THAT PRECIPITATION WILL BE INCREASING IN THE  
PACIFIC NORTHWEST AND NORTHERN ROCKIES WITH THE UPPER TROUGH  
COMING IN. COASTAL AND VALLEY RAIN AND MOUNTAIN SNOW ARE LIKELY  
OVER THE PACIFIC NORTHWEST SPREADING INTO CALIFORNIA, THE GREAT  
BASIN, AND THE ROCKIES THROUGH THE EARLY PART OF NEXT WEEK. SNOW  
COULD ALSO SPREAD FARTHER EAST INTO THE NORTHERN HIGH PLAINS  
SUNDAY AND INTO THE REST OF THE NORTHERN TIER STATES AS THE FIRST  
HALF OF THE WEEK PROGRESSES. THE CONFIDENCE IN THE AXIS OF  
HEAVIEST SNOW AND SNOWFALL AMOUNTS REMAINS SOMEWHAT LOW. FARTHER  
SOUTH, MOIST INFLOW IS FORECAST TO RETURN TO THE SOUTH-CENTRAL AND  
SOUTHEASTERN U.S., WITH INCREASING CHANCES FOR HEAVY TO POSSIBLY  
EXCESSIVE RAINFALL. MODELS SEEM TO BE CONVERGING ON PORTIONS OF  
THE GULF COAST STATES/TENNESSEE VALLEY AS THE GREATEST THREAT FOR  
HEAVY RAINFALL NEXT MONDAY-TUESDAY, WITH SOME GUIDANCE SUGGESTING  
THE THREAT MAY CONTINUE INTO WEDNESDAY OVER ROUGHLY THE SAME AREA.  
THERE REMAIN PLENTY OF UNCERTAINTY IN THE DETAILS WHICH LIKELY ARE  
GOING TO TAKE ANOTHER FEW DAYS TO RESOLVE, BUT REGARDLESS, THE  
PATTERN ITSELF WOULD SUPPORT SOME SORT OF HEAVY RAINFALL/POSSIBLE  
SEVERE WEATHER THREAT (AS NOTED BY SPC) EARLY NEXT WEEK.  
 
TEMPERATURES THIS WEEKEND ARE EXPECTED TO BE ABOVE NORMAL FOR  
PARTS OF THE WEST INTO THE PLAINS, WITH THE LARGEST ANOMALIES OF  
HIGHS 20+ DEGREES ABOVE AVERAGE OVER SOUTH DAKOTA AND NEBRASKA.  
MEANWHILE, COOLER TO NEAR AVERAGE TEMPERATURES OVER THE EASTERN  
THIRD OF THE COUNTRY SATURDAY WILL WARM SUNDAY. AS THE PATTERN  
AMPLIFIES, THE SOUTH-CENTRAL U.S. TO THE EAST COAST WILL FURTHER  
WARM THROUGH THE FIRST HALF OF NEXT WEEK, WITH WIDESPREAD HIGHS  
10-20F AND LOWS 20-30F ABOVE NORMAL. MEANWHILE, A COLD ARCTIC HIGH  
IS FORECAST TO EXPAND ACROSS THE NORTH-CENTRAL U.S., LEADING TO  
WELL BELOW AVERAGE TEMPERATURES INITIALLY ACROSS THE NORTHERN HIGH  
PLAINS AND SPREADING SOUTHWARD (AS FAR SOUTH AND THE OK/TX  
PANHANDLES) THROUGH MIDWEEK. TEMPERATURES IN SOME PLACES COULD BE  
30 OR MORE DEGREES BELOW NORMAL, AND HIGHS IN THE SINGLE DIGITS  
ARE EXPECTED FOR MONTANA AND THE DAKOTAS MONDAY AND TUESDAY.  
 
SANTORELLI/TATE  
 
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  
 
HAZARDS:  
- HEAVY RAIN ACROSS PORTIONS OF THE LOWER/MIDDLE MISSISSIPPI  
VALLEY, THE OHIO/TENNESSEE VALLEY, THE  
SOUTHERN APPALACHIANS, AND THE SOUTHEAST, MON-WED, FEB 21-FEB 23.  
- HEAVY SNOW ACROSS PORTIONS OF THE PACIFIC NORTHWEST AND THE  
NORTHERN GREAT BASIN, SAT-SUN, FEB  
19-FEB 20.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE NORTHEAST, THE CENTRAL  
APPALACHIANS, THE MIDDLE  
MISSISSIPPI VALLEY, THE MID-ATLANTIC, THE GREAT LAKES, AND THE  
OHIO VALLEY.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE GREAT  
PLAINS, THE CENTRAL GREAT BASIN, THE  
NORTHERN/CENTRAL ROCKIES, AND THE UPPER/MIDDLE MISSISSIPPI VALLEY,  
MON-WED, FEB 21-FEB 23.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF MAINLAND ALASKA, MON, FEB  
21.  
 
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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