383  
FXUS02 KWBC 041952  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
250 PM EST FRI MAR 04 2022  
 
VALID 12Z MON MAR 07 2022 - 12Z FRI MAR 11 2022  
   
..HEAVY RAIN POTENTIAL ACROSS THE OHIO VALLEY INTO MONDAY
 
 
   
..OVERVIEW
 
 
THE MEDIUM RANGE PERIOD BEGINS MONDAY WITH BROAD TROUGHING (WITH  
EMBEDDED SHORTWAVES) ACROSS THE CENTRAL U.S. PUSHING A COLD FRONT  
INTO THE EAST. THIS SETUP BRINGS A THREAT FOR HEAVY TO EXCESSIVE  
RAINFALL ACROSS THE OHIO VALLEY, WITH SNOW TO THE NORTH.  
SHORTWAVES SHOULD WEAKEN IN THE FLOW AS THEY PROGRESS DOWNSTREAM  
AS HEIGHTS BEGIN TO RISE OVER THE EAST COAST. OUT WEST, A STRONG  
RIDGE OVER THE EAST PACIFIC SHOULD ALLOW FOR SHORTWAVES TO KEEP  
REINFORCED TROUGHING OVER THE ROCKIES, WHICH EVENTUALLY SHOULD  
PRESS EAST INTO THE PLAINS BY LATE NEXT WEEK.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
REASONABLY GOOD MODEL AGREEMENT CONTINUES FOR THE LARGE SCALE  
PATTERN OVER THE LAST COUPLE OF MODEL CYCLES, BUT WITH TYPICAL  
TIMING AND DETAIL DIFFERENCES REMAINING, SOME OF WHICH COULD BE  
IMPACTFUL TO SENSIBLE WEATHER. THERE IS GOOD CONSENSUS FOR  
ELONGATED LOW PRESSURE ALONG THE COLD FRONT AT THE BEGINNING OF  
THE PERIOD MONDAY, WITH LINGERING DIFFERENCES IN THE EXACT  
PLACEMENT OF THE SURFACE LOW OR TWO DEPENDENT ON SHORTWAVE  
DIFFERENCES. THE COLD FRONT MOVING EASTWARD HAS TRENDED A BIT  
FASTER COMPARED TO THE PREVIOUS FORECAST AS THE LOW TRACKS QUICKLY  
ACROSS THE NORTHEAST. A BLEND OF THE DETERMINISTIC GUIDANCE  
FAVORING THE GFS AND ECMWF WORKED WELL FOR THIS SYSTEM.  
 
FARTHER WEST, ENERGY DIVING SOUTH ALONG THE WEST COAST ON MONDAY  
PRODUCES DIFFERENCES THAT BECOME MORE NOTABLE TUESDAY AND BEYOND.  
MODELS HAVE BEEN WAFFLING ON HOW MUCH ENERGY IS HELD BACK ACROSS  
THE SOUTHWEST TUESDAY, WITH THE BULK OF 00Z GUIDANCE SHOWED A  
SLOWER TRACK AND A POSSIBLY CLOSED LOW COMPARED TO THE PREVIOUS  
CYCLE, THOUGH THE 06Z GFS WAS OPEN AND FASTER. THIS TREND TOWARD A  
SLOWER/STRONGER SOLUTION WAS REFLECTED IN THE WPC 500MB CHARTS.  
THE NEWER 12Z GUIDANCE STILL SHOWS A BIT OF SPREAD, WITH THE CMC  
NOW AMONG THE FASTER/WEAKER GUIDANCE AFTER THE PAST FEW RUNS OF IT  
BEING SLOW, BUT OVERALL MODEL CONSENSUS IS STILL SLOWER COMPARED  
TO ABOUT A DAY AGO. THE DETAILS OF THIS FEATURE REMAIN UNCERTAIN  
TUESDAY AND THEN BEYOND AS IT EJECTS EASTWARD WITH VARIED  
TIMING--WHICH INFLUENCES THE GULF OF MEXICO RETURN FLOW AND TIMING  
OF RAINFALL BEGINNING ACROSS THE SOUTHEASTERN QUADRANT OF THE  
COUNTRY. ANOTHER FACTOR TO CONSIDER WITH THAT IS THE TROUGH'S  
EASTWARD EXTENT FOR THE LATTER HALF OF THE WEEK, WHICH APPEARS TO  
HAVE TRENDED WESTWARD (ALLOWING FOR HIGHER HEIGHTS IN THE EAST)  
OVER THE PAST COUPLE OF DAYS, KEEPING RAIN CHANCES IN THE  
FORECAST.  
 
BY MIDWEEK THROUGH THURSDAY AND FRIDAY, THE NEXT SHORTWAVE ARRIVES  
INTO THE NORTHWEST, WHICH SHOULD HELP TO REINFORCE BROAD TROUGHING  
OVER THE ROCKIES WHICH EVENTUALLY PUSHES INTO THE CENTRAL U.S. BY  
THE END OF THE WEEK. THERE ARE SOME TIMING DIFFERENCES REGARDING  
BOTH THE TROUGH AXIS AND THE ASSOCIATED SURFACE FRONT AND  
DEVELOPING LOW PRESSURE. ECMWF RUNS HAVE GENERALLY BEEN SLOWER  
THAN GFS RUNS, AND THE WPC FORECAST FOR THE LATTER PART OF THE  
PERIOD ATTEMPTED TO TAKE A MIDDLE GROUND APPROACH BY PHASING IN  
AND INCREASING THE PROPORTIONS OF THE REASONABLY AGREEABLE  
ENSEMBLE MEANS, WITH SOME INCLUSION OF THE DETERMINISTIC RUNS FOR  
A LITTLE ADDED SYSTEM DEFINITION.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
RAIN AND THUNDERSTORMS WILL BE WIDESPREAD ALONG AND AHEAD OF THE  
COLD FRONT MOVING THROUGH THE EASTERN U.S. EARLY NEXT WEEK. THE  
AXIS OF THE HEAVIEST RAIN BY MONDAY IS FORECAST FROM THE LOWER  
OHIO VALLEY INTO THE CENTRAL APPALACHIANS AND NORTHERN  
MID-ATLANTIC. FLOODING AND FLASH FLOODING ARE POSSIBLE  
PARTICULARLY IN AREAS THAT SEE REPEAT/TRAINING CONVECTION AND IN  
AREAS WHERE SOILS ARE ALREADY WET, AND NEWLY EXPERIMENTAL SLIGHT  
RISKS OF EXCESSIVE RAINFALL REMAIN IN PLACE FOR DAY 4. A SWATH OF  
WINTRY PRECIPITATION COULD DEVELOP ON THE NORTH SIDE, WITH LIGHT  
TO MODERATE AMOUNTS POSSIBLE FROM INTO THE GREAT LAKES AND  
INTERIOR NORTHEAST. THEN BY THE MIDDLE OF NEXT WEEK, GULF MOISTURE  
COULD RETURN TO THE LOWER MISSISSIPPI VALLEY AND SOUTHEAST, BUT  
UNCERTAINTY REMAINS WITH RESPECT TO RAINFALL TOTALS AND TIMING,  
ALL DEPENDENT ON A STALLING BOUNDARY AND POSSIBLE WAVES OF LOW  
PRESSURE.  
 
THE WEST SHOULD SEE A BREAK IN THE PRECIPITATION ON MONDAY, BUT  
MOUNTAINS SNOWS RETURN BY TUESDAY AND BEYOND FOR THE PACIFIC  
NORTHWEST AND ESPECIALLY THE ROCKIES. THERE REMAINS SOME  
POTENTIAL, BUT LOW CONFIDENCE, ON SNOWFALL INTO THE NORTHERN  
PLAINS/UPPER MIDWEST LATE WEEK AS LOW PRESSURE MAY DEVELOP OVER  
THE CENTRAL STATES.  
 
TEMPERATURES SHOULD FEEL VERY MILD FOR THE SOUTH-CENTRAL TO  
EASTERN PART OF THE U.S. ON MONDAY AHEAD OF THE COLD FRONT, WITH  
TEMPERATURES 10 TO 30 DEGREES ABOVE AVERAGE AND DOZENS OF DAILY  
RECORD HIGH MINIMUM AND MAXIMUM TEMPERATURES POSSIBLE.  
TEMPERATURES SHOULD MODERATE BACK TO NEAR NORMAL AFTER THE FRONTAL  
PASSAGE ON TUESDAY. THE WEST AND PARTS OF THE CENTRAL U.S. WILL  
GENERALLY BE COOLER THAN AVERAGE THROUGH MUCH OF THE PERIOD, BUT  
PARTICULARLY FOR THE SECOND HALF OF THE WEEK AS MORE SUBSTANTIAL  
TROUGHING DEVELOPS AND PUSHES SOUTHEAST ALONG WITH COLD HIGH  
PRESSURE. TEMPERATURES SHOULD TREND COOLER WITH ANOMALIES 10 TO 30  
DEGREES BELOW NORMAL POSSIBLE ACROSS THE NORTHERN AND CENTRAL  
PLAINS, AND AS FAR SOUTH AS TEXAS AND OKLAHOMA BY FRIDAY.  
 
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  
 
HAZARDS:  
- HEAVY RAIN ACROSS PORTIONS OF THE SOUTHEAST, THE MID-ATLANTIC,  
THE LOWER MISSISSIPPI VALLEY, THE SOUTHERN APPALACHIANS, AND THE  
TENNESSEE VALLEY, WED-THU, MAR 9-MAR 10.  
- HEAVY RAIN ACROSS PORTIONS OF THE SOUTHERN APPALACHIANS, THE  
GREAT LAKES, THE MID-ATLANTIC, THE CENTRAL APPALACHIANS, AND THE  
OHIO VALLEY, MON, MAR 7.  
- HEAVY SNOW ACROSS PORTIONS OF THE NORTHEAST AND THE GREAT LAKES,  
MON, MAR 7.  
- SEVERE WEATHER ACROSS PORTIONS OF THE SOUTHEAST, THE LOWER  
MISSISSIPPI VALLEY, THE SOUTHERN APPALACHIANS, AND THE TENNESSEE  
VALLEY, MON, MAR 7.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE CENTRAL GREAT BASIN.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE MIDDLE  
MISSISSIPPI VALLEY, THE CENTRAL GREAT BASIN, THE OHIO VALLEY, THE  
NORTHERN ROCKIES, AND THE TENNESSEE VALLEY.  
- FLOODING LIKELY ACROSS PORTIONS OF THE CENTRAL GREAT BASIN.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
PLAINS AND THE SOUTHERN PLAINS, MON-TUE, MAR 7-MAR 8 AND FRI, MAR  
11.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
PLAINS, THE MIDDLE MISSISSIPPI VALLEY, THE SOUTHERN PLAINS, THE  
UPPER MISSISSIPPI VALLEY, AND THE NORTHERN PLAINS, FRI, MAR 11.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
ROCKIES, THE CENTRAL PLAINS, THE UPPER MISSISSIPPI VALLEY, THE  
NORTHERN PLAINS, AND THE NORTHERN ROCKIES, WED-FRI, MAR 9-MAR 11.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
ROCKIES AND THE CENTRAL PLAINS, MON-FRI, MAR 7-MAR 11.  
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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