795  
FXUS02 KWBC 182035  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
434 PM EDT FRI MAR 18 2022  
 
VALID 12Z MON MAR 21 2022 - 12Z FRI MAR 25 2022  
 
...STRONG LOW PRESSURE SYSTEM WILL LIKELY PRODUCE HEAVY  
RAIN/SEVERE STORMS ACROSS PORTIONS OF THE SOUTHERN U.S. AND HEAVY  
CENTRAL ROCKIES SNOW BY EARLY NEXT WEEK...  
   
..OVERVIEW
 
 
THE DOMINANT FOCUS OF THE MEDIUM RANGE FORECAST WILL BE AN UPPER  
LOW EXPECTED TO TRACK NORTHEAST FROM THE FOUR CORNERS STATES  
MONDAY ONWARD, POSSIBLY OPENING UP AS NORTHERN STREAM ENERGY  
PHASES WITH IT AFTER MIDWEEK. THIS FEATURE WILL SUPPORT STRONG LOW  
PRESSURE THAT SHOULD TRACK FROM THE SOUTHERN HIGH PLAINS THROUGH  
THE GREAT LAKES AND NEW ENGLAND/SOUTHEASTERN CANADA. EXPECT THE  
SYSTEM TO SPREAD A MYRIAD OF SIGNIFICANT AND HAZARDOUS WEATHER  
ACROSS THE EASTERN TWO-THIRDS OF THE LOWER 48, INCLUDING  
POTENTIALLY HEAVY SNOW OVER THE CENTRAL ROCKIES AND VICINITY,  
HEAVY RAIN FROM THE SOUTH-CENTRAL U.S. TO THE OHIO/TENNESSEE  
VALLEYS AND SOUTHEAST, AND SEVERE THUNDERSTORMS FROM TEXAS THROUGH  
THE DEEP SOUTH. SOME PRECIPITATION IN THE NORTHERN FRINGE OF THE  
MOISTURE SHIELD COULD BE IN THE FORM OF SNOW OVER THE  
CENTRAL/EASTERN U.S. AS WELL. BEHIND THIS SYSTEM A STRONG UPPER  
RIDGE WILL BUILD INTO THE WEST, BRINGING MOSTLY DRY AND WARM  
WEATHER TO THE REGION. THE ANOMALOUS WARMTH OVER THE WEST COULD  
BRING RECORD HIGHS TO PARTS OF CALIFORNIA AROUND TUESDAY-THURSDAY.  
PACIFIC SHORTWAVE ENERGY MAY ERODE THE WESTERN RIDGE SOMEWHAT LATE  
IN THE WEEK.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
DURING THE FIRST HALF OF THE PERIOD, THE LATEST 00Z/06Z  
OPERATIONAL MODEL CONSENSUS PROVIDES A GOOD DEPICTION OF  
SIGNIFICANT FEATURES. GUIDANCE MAINTAINS THE RECENT TENDENCY TO  
KEEP THE CENTRAL U.S. UPPER LOW INTACT INTO WEDNESDAY AS IT  
REACHES THE MIDWEST. THERE ARE STILL NOTICEABLE DIFFERENCES WITH  
SPECIFICS AT THE SURFACE BUT THESE HAVE LOWER PREDICTABILITY DUE  
TO SENSITIVITY TO EXACT SHORTWAVE DETAILS ALOFT. MEANWHILE  
GUIDANCE HAS BECOME MORE AGREEABLE WITH THE CYCLONIC FLOW OVER THE  
NORTHEAST DURING THE FIRST HALF OF THE WEEK, WITH SOLUTIONS  
GENERALLY GRAVITATING TO AN EVOLUTION BETWEEN THE EXTREMES SEEN IN  
EARLIER GFS AND ECMWF CLUSTERS. MEANWHILE THE UPPER RIDGE BUILDING  
INTO THE WEST SHOULD BE STRONGEST DURING TUESDAY-WEDNESDAY.  
 
THE LATTER HALF OF THE FORECAST STILL CONTAINS VARIOUS  
UNCERTAINTIES, IN PARTICULAR EXACTLY HOW PACIFIC SHORTWAVE ENERGY  
WILL DAMPEN THE NORTHERN PART OF THE WESTERN NORTH AMERICA RIDGE.  
THESE DETAILS AFFECT HOW SOUTHERN TIER CANADA FLOW MAY INTERACT  
WITH UPPER LOW REACHING THE MIDWEST BY MIDWEEK, AND THEN HOW MUCH  
IF ANY FLOW SEPARATION MAY OCCUR IN THE VICINITY OF THE NORTHEAST  
U.S. AND SOUTHEASTERN CANADA PLUS TIMING OF THE REST OF THE TROUGH  
OVER THE LOWER 48. THUS FAR THE ENSEMBLES SUGGEST THAT THE 00Z  
GFS/CMC MAY BE OVERDONE WITH HOW MUCH SEPARATION OCCURS OVER  
EASTERN NORTH AMERICA AND THE 06Z GFS HAS PARTIALLY NUDGED BACK  
TOWARD CONSENSUS. FARTHER SOUTH/SOUTHWEST, THE MAJORITY SAYS THE  
UPPER TROUGH SHOULD EXTEND BACK INTO NORTHERN MEXICO INTO LATE  
WEEK. THE 00Z ECMWF COULD BE A BIT FAST, THOUGH MUCH IMPROVED OVER  
ITS PRIOR RUN AND NOT EXTREME VERSUS ITS ENSEMBLE MEMBERS. THE 00Z  
CMC LEANS TO THE WEAKER SIDE OF THE FULL SPREAD WITH THE WESTERN  
RIDGE LATE IN THE PERIOD. GUIDANCE COMPARISONS LED TO TRENDING THE  
OPERATIONAL MODEL BLEND TOWARD 40-50 PERCENT 06Z GEFS/00Z ECMWF  
MEANS BY DAYS 6-7 THURSDAY-FRIDAY WITH LINGERING MODEL INPUT FROM  
THE 06Z GFS/00Z ECMWF.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
AMPLE GULF OF MEXICO MOISTURE FLOWING INTO THE SURFACE/UPPER-LEVEL  
LOWS TRACKING NORTHEASTWARD OVER THE CENTRAL U.S. WILL LEAD TO  
WIDESPREAD RAIN AND THUNDERSTORMS FOR THE SOUTHERN PLAINS AND  
LOWER MISSISSIPPI VALLEY EARLY IN THE WEEK, SPREADING EASTWARD  
INTO THE OHIO AND TENNESSEE VALLEYS AND SOUTHEAST BY AROUND  
MIDWEEK. PER THE STORM PREDICTION CENTER, STORMS COULD BE SEVERE  
IN EASTERN TEXAS MONDAY AND ACROSS THE GULF COAST STATES AS THE  
WEEK PROGRESSES. FURTHERMORE, HEAVY RAIN IS LIKELY TO CAUSE AREAS  
OF FLASH FLOODING PARTICULARLY DUE TO HEAVY RAIN RATES MONDAY INTO  
WEDNESDAY, AND SLIGHT RISK AREAS ARE INDICATED NEAR THE  
ARK-LA-TEX/EASTERN OKLAHOMA AND FOR THE LOWER MISSISSIPPI  
VALLEY/MID-SOUTH REGION FOR DAYS 4 AND 5 IN THE EXPERIMENTAL WPC  
MEDIUM RANGE EXCESSIVE RAINFALL OUTLOOK. RAIN SHOULD SPREAD INTO  
THE EASTERN SEABOARD AROUND THURSDAY. ADDITIONALLY, HEAVY SNOW IS  
INCREASINGLY LIKELY FOR THE CENTRAL ROCKIES MONDAY, WITH SOME  
POTENTIAL FOR SNOW TO SPREAD INTO THE HIGH PLAINS AS WELL. AN AREA  
OF ENHANCED RAINFALL ALSO APPEARS LIKELY FROM THE CENTRAL PLAINS  
INTO MIDDLE MISSISSIPPI VALLEY/MIDWEST, THOUGH WITH LESSER TOTALS  
THAN THOSE EXPECTED FARTHER SOUTHEAST. THERE IS A GRADUAL  
IMPROVEMENT IN AGREEMENT THAT AT LEAST SOME PRECIPITATION SHOULD  
REACH AREAS FROM THE NORTHERN PARTS OF THE PLAINS THROUGH THE  
NORTHEAST, WITH SOME OF THIS MOISTURE POSSIBLY PRODUCING SNOW.  
PROBABILITIES FOR AT LEAST A QUARTER INCH LIQUID IN THE FORM OF  
SNOW ARE STILL RELATIVELY LOW THOUGH. IN THE WEST, THE PACIFIC  
NORTHWEST SHOULD SEE AN EPISODE OF RAIN/HIGH ELEVATION SNOW ON  
MONDAY AND POSSIBLY A LITTLE LIGHT/SCATTERED ACTIVITY LATER IN THE  
WEEK. OTHERWISE THE WEST WILL SEE DRY WEATHER THROUGH THE WEEK.  
 
THE STRONG UPPER RIDGE BUILDING INTO THE WEST WILL LEAD TO A BROAD  
AREA OF HIGHS 10-20F ABOVE NORMAL TUESDAY-FRIDAY WITH SLIGHTLY  
HIGHER LOCALIZED ANOMALIES POSSIBLE. BEST POTENTIAL TO REACH DAILY  
RECORD HIGHS WILL BE OVER CALIFORNIA DURING TUESDAY-THURSDAY.  
DAMPENING OF THE NORTHERN PART OF THE UPPER RIDGE BY FRIDAY MAY  
START A GRADUAL COOLING TREND OVER SOME AREAS BUT ALSO SPREAD THE  
WARMTH ACROSS THE EASTERN GREAT BASIN AND SOUTHWEST/FOUR CORNERS  
REGION. LEADING UPPER LEVEL TROUGHING WILL SUPPORT HIGH  
TEMPERATURES 10-20F BELOW AVERAGE ACROSS THE INTERMOUNTAIN WEST  
MONDAY AND THE CENTRAL/SOUTHERN HIGH PLAINS TUESDAY AND WEDNESDAY.  
THE COOLER AIR SHOULD MODERATE CLOSER TO NORMAL BY THE LATTER PART  
OF NEXT WEEK AND COULD TREND MODERATELY ABOVE NORMAL FRIDAY. AHEAD  
OF THE PLAINS STORM, THE MIDWEST WILL SEE WARMER THAN AVERAGE  
TEMPERATURES BY AROUND 20F OR SO ON MONDAY AND GENERALLY WARMER  
THAN NORMAL CONDITIONS ARE LIKELY ACROSS MUCH OF THE EASTERN THIRD  
OF THE U.S. FOR MOST OF THE WEEK. ISOLATED RECORD HIGHS ARE  
POSSIBLE OVER PARTS OF FLORIDA TUESDAY-WEDNESDAY.  
 
RAUSCH/TATE  
 
HAZARDS:  
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL ROCKIES AND CENTRAL  
HIGH PLAINS, MON, MAR 21.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE CENTRAL HIGH PLAINS,  
MON, MAR 21.  
- SEVERE WEATHER ACROSS PORTIONS OF THE SOUTHERN PLAINS TO THE THE  
LOWER MISSISSIPPI VALLEY, MON, MAR 21.  
- HEAVY RAIN ACROSS PORTIONS OF THE SOUTHERN PLAINS TO THE LOWER  
MISSISSIPPI VALLEY, MON, MAR 21.  
- HIGH WINDS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH  
PLAINS, TUE, MAR 22.  
- SEVERE WEATHER ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY,  
THE TENNESSEE VALLEY, AND THE CENTRAL GULF COAST, TUE, MAR 22.  
- HEAVY RAIN ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY, THE  
MIDDLE MISSISSIPPI VALLEY, THE TENNESSEE VALLEY, THE OHIO VALLEY,  
AND THE CENTRAL GULF COAST, TUE, MAR 22.  
- SEVERE WEATHER ACROSS PORTIONS OF THE SOUTHEAST, WED, MAR 23.  
- HEAVY RAIN ACROSS PORTIONS OF THE SOUTHEAST, THE SOUTHERN  
APPALACHIANS, AND THE MID-ATLANTIC, WED, MAR 23.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI  
VALLEY AND THE GREAT LAKES.  
- MUCH ABOVE NORMAL TEMPERATURES ACROSS PORTIONS OF CALIFORNIA,  
TUE-THU, MAR 22-MAR 24.  
 
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  
 
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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