828  
FXUS02 KWBC 110655  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
254 AM EDT MON APR 11 2022  
 
VALID 12Z THU APR 14 2022 - 12Z MON APR 18 2022  
 
   
..OVERVIEW
 
 
A STRONG SPRINGTIME LOW PRESSURE SYSTEM WILL BE EXITING THE UPPER  
MIDWEST AS THE PERIOD BEGINS THURSDAY, AS ITS ATTENDANT COLD FRONT  
SLIDES THROUGH THE EAST. AFTER THURSDAY/DAY 3, THE PATTERN FINALLY  
APPEARS TO DEAMPLIFY SOMEWHAT AS A WEAKER SHORTWAVE/TROUGH MOVES  
INTO THE WEST AROUND FRIDAY-SATURDAY. GUIDANCE SHOWS THIS TROUGH  
MOVING EASTWARD WITH TIME EVENTUALLY INTO THE CENTRAL PLAINS WHERE  
IT COULD INDUCE ANOTHER LOW PRESSURE SYSTEM ACROSS THE MIDWEST  
NEXT MONDAY. THIS COULD BRING ANOTHER ROUND OF PRECIPITATION INTO  
THE NORTHERN AND EASTERN PART OF THE COUNTRY EARLY NEXT WEEK,  
ALTHOUGH THERE'S STILL PLENTY OF UNCERTAINTY WITH RESPECT TO THE  
DETAILS.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE LATEST MODELS AND ENSEMBLES FINALLY SEEM TO SHOW SOME DECENT  
AGREEMENT ON THE LARGE SCALE EVOLUTION OF THE DEPARTING DEEP UPPER  
LOW INTO EASTERN CANADA THURSDAY-FRIDAY, WHICH LOOKS TO  
MEANDER/WEAKEN THERE AS IT GETS BLOCKED BY AMPLIFIED WESTERN  
ATLANTIC RIDGING. MODELS SHOW VARYING DEGREES OF UNCERTAINTY  
REGARDING SHORTWAVE ENERGY ROUNDING THE BASE OF THIS THROUGH THE  
SOUTHEAST, WITH SECONDARY LOW PRESSURE DEVELOPING ALONG THE COLD  
FRONT OFF THE NORTHEAST COAST NEXT FRIDAY. THE ECMWF HAS BOTH BEEN  
MOST CONSISTENT AND STRONGEST WITH THIS, WHICH OF COURSE HAS  
IMPLICATIONS FOR HOW MUCH PRECIPITATION LINGERS ACROSS THE  
SOUTHEAST/EAST COAST INTO NEXT WEEKEND. A GENERAL DETERMINISTIC  
MODEL BLEND (WITH SLIGHT WEIGHTING TOWARDS THE ECMWF FOR  
CONTINUITY REASONS) SEEMED TO PROVIDE A GOOD STARTING POINT FOR  
DAYS 3-4.  
 
OUT WEST, THE MODELS CONTINUE TO SHOW A LOT OF UNCERTAINTY  
SURROUNDING THE NEXT TROUGH THROUGH THE REGION. THERE'S GOOD  
AGREEMENT ON LOW PRESSURE PRESENT NEAR THE COAST ON DAY 3, BUT  
AFTER THAT QUESTIONS BEGIN TO ARISE REGARDING STRENGTH AND TIMING  
OF THE MAIN TROUGH AXIS THROUGH THE NORTHWEST. THE ECMWF AND UKMET  
ARE STRONGEST/MOST AMPLIFIED WITH THIS TROUGH AND ALSO DOWNSTREAM  
RIDGING ACROSS THE NORTH-CENTRAL U.S.. BY DAY 6, THE LATEST RUNS  
OF THE ECMWF AND GFS SHOW PRETTY GOOD AGREEMENT ON TIMING OF THE  
WAVE INTO THE CENTRAL U.S., BUT POOR RUN TO RUN CONTINUITY ON THIS  
FEATURE WHICH TEMPERS CONFIDENCE QUITE A BIT. THE CMC IS ENTIRELY  
TOO WEAK/FLAT WITH THIS SYSTEM AND WAS NOT INCLUDED IN THE BLEND  
AFTER DAY 4. THE ECMWF CONTINUES TO BE NOTABLY STRONGER WITH THE  
WAVE INTO THE MIDWEST ON MONDAY/DAY 7, INDICATING A DEEP CLOSED  
LOW AND WELL DEFINED LOW PRESSURE SYSTEM AT THE SURFACE. PREFER A  
BLEND TOWARDS THE BETTER AGREEABLE (AND WEAKER) ENSEMBLE MEANS FOR  
THE LATTER PERIODS TO HELP MITIGATE THE HARDER TO RESOLVE  
DIFFERENCES.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
SOME LINGERING SNOWS ARE POSSIBLE ACROSS THE UPPER MIDWEST AT THE  
START OF THURSDAY, BUT THE HEAVIEST SHOULD BE RAPIDLY COMING TO AN  
END AS THE DEEP LOW DEPARTS INTO CANADA. GUSTY WINDS ARE LIKELY TO  
CONTINUE INTO FRIDAY THOUGH CREATING BLOWING AND DRIFTING OF SNOW  
AND POSSIBLE HAZARDOUS TRAVEL CONDITIONS. MODERATE TO LOCALLY  
HEAVY RAINFALL SHOULD BE MOVING THROUGH THE EAST AHEAD OF THE  
ATTENDANT COLD FRONT ON THURSDAY INTO FRIDAY, WITH THE BEST CHANCE  
FOR HEAVIER TOTALS ACROSS PARTS OF THE SOUTHEAST WHERE THE BETTER  
MOISTURE AND INSTABILITY WILL BE PRESENT. RAINFALL ACROSS THE  
SOUTHEAST COULD LINGER INTO THE WEEKEND AS THE WESTERN EDGE OF THE  
BOUNDARY TRIES TO LIFT NORTH AS A WARM FRONT AND WEAKEN ACROSS THE  
SOUTHEAST. OUT WEST, MODERATE TO HEAVY RAIN/MOUNTAIN SNOWS ARE  
POSSIBLE ACROSS PARTS OF CALIFORNIA/OREGON WITH THE NEXT LOW  
PRESSURE SYSTEM THURSDAY-FRIDAY. MOISTURE SHOULD SPREAD EAST INTO  
THE INTERMOUNTAIN WEST AND NORTHERN PLAINS NEXT WEEKEND.  
SIGNIFICANT UNCERTAINTY REGARDING LOW PRESSURE INTO THE MIDWEST  
NEXT WEEK, BUT THE LATEST GUIDANCE SUGGESTS DECENT PROBABILITY FOR  
ANOTHER ROUND OF PRECIPITATION TO AFFECT THE NORTHERN AND EASTERN  
STATES EARLY NEXT WEEK.  
 
THE CORE OF THE BELOW NORMAL TEMPERATURES ARE LIKELY ACROSS THE  
NORTHERN HIGH PLAINS INTO EARLY NEXT WEEK, WITH DAYTIME HIGHS  
AROUND 20-30 DEGREES BELOW NORMAL POSSIBLE. OUT WEST, BELOW NORMAL  
TEMPERATURES SHOULD MODERATE BACK TOWARDS NORMAL LATER IN THE  
PERIOD AS RIDGING TRIES TO BUILD OVER THE REGION. ABOVE NORMAL  
TEMPERATURES ALONG THE EASTERN SEABOARD INITIALLY SHOULD TREND  
BACK TOWARDS NORMAL NEXT WEEKEND. BELOW NORMAL TEMPERATURES WILL  
SPREAD SOUTH AND EAST NEXT SUNDAY-MONDAY INTO THE MIDWEST WITH  
SOME READINGS 10-20F POSSIBLE.  
 
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, EXPERIMENTAL EXCESSIVE RAINFALL  
OUTLOOK, 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/#PAGE=ERO  
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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