182  
FXUS02 KWBC 090705  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
204 AM EST WED MAR 09 2022  
 
VALID 12Z SAT MAR 12 2022 - 12Z WED MAR 16 2022  
 
...WINTER STORM CONTINUES INTO EARLY SUNDAY FOR PARTS OF THE  
NORTHEAST...  
 
   
..OVERVIEW
 
 
AMPLIFIED TROUGHING IN THE EAST TO START THE PERIOD WILL SUPPORT  
STRONG CYCLOGENESIS AND RAPID DEEPENING OF A SURFACE LOW THROUGH  
THE NORTHEAST ON SATURDAY. THIS CLASSIC SPRING SYSTEM WILL BRING  
SNOW TO THE NORTH/NORTHWEST OF THE LOW, AND RAINFALL EXITING THE  
EAST COAST, WITH CHILLY WEATHER TO FOLLOW THROUGH THE EASTERN  
THIRD OF THE NATION THIS WEEKEND. MEANWHILE, THE NEXT SHORTWAVE  
MOVES INTO THE NORTHWEST ON SUNDAY, WITH A VERY UNCERTAIN  
EVOLUTION AS IT MOVES INTO THE EAST EARLY NEXT WEEK. UPPER RIDGING  
SHOULD BUILD ACROSS THE CENTRAL U.S. LATE PERIOD, AS ANOTHER,  
STRONGER, TROUGH MOVES INTO THE WEST NEXT TUESDAY-WEDNESDAY.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
ON THE LARGE SCALE, MODELS CONTINUE TO HONE IN ON A SIGNIFICANT  
EAST COAST SYSTEM BY THE START OF THE PERIOD ON SATURDAY. DETAILS  
ARE STARTING TO BE WORKED OUT AS WELL, WITH EXPLOSIVE DEEPENING  
LIKELY UP THE NORTHEAST COAST INTO SUNDAY. THE 12Z/MAR 8 RUN OF  
THE CMC WAS A LITTLE FASTER/FARTHER EAST WITH THE SURFACE LOW, BUT  
THE 00Z RUN SEEMS TO HAVE COME IN LINE. A GENERAL MODEL BLEND OF  
THE DETERMINISTIC SOLUTIONS SEEMS TO REPRESENT WELL FOR THIS LOW.  
 
A SHORTWAVE INTO THE PACIFIC NORTHWEST ON SUNDAY SHOWS GOOD  
AGREEMENT ON TIMING, BUT SIGNIFICANT UNCERTAINTIES BEGIN TO ARISE  
FARTHER DOWNSTREAM. THE ECMWF HAS BEEN CONSISTENTLY MUCH MORE  
PHASED/QUICKER WITH THE TROUGH AS IT AMPLIFIES AND MOVES INTO THE  
EAST EARLY NEXT WEEK. MEANWHILE, THE GFS HAS BEEN PRETTY  
CONSISTENT WITH A SEPARATION OF STREAMS WITH THE SOUTHERN STREAM  
CLOSING OFF A LOW OVER THE SOUTH. YESTERDAYS 12Z RUN OF THE CMC  
WAS A NICE MIDDLE GROUND. FOR THE NEW 00Z RUNS TODAY (AVAILABLE  
AFTER FORECAST ISSUANCE TIME), THE GFS STAYED CONSISTENT WITH  
ITSELF, THE CMC SPED UP TO LOOK LIKE THE 12Z EC, BUT THE 00Z EC  
SHOWED THE MOST DRAMATIC SHIFT, WITH A CLOSED LOW FEATURE (ALBEIT  
QUICKER THAN THE GFS). THERE IS ENOUGH SUPPORT FOR THAT STRONGER  
FEATURE IN VARIOUS ENSEMBLE MEMBERS (BOTH FROM THE EC AND THE GFS)  
TO SHOW A HINT OF A SHORTWAVE/SYSTEM OVER THE SOUTHEAST TOWARDS  
THE END OF THE PERIOD IN THE ENSEMBLE MEANS. THE NEXT TROUGH INTO  
THE WEST TUESDAY-WEDNESDAY SHOWS SOME TIMING UNCERTAINTY (GFS  
FASTER, EC/CMC SLOWER). THE WPC FORECAST AFTER DAY 5, TRENDED  
RATHER QUICKLY TOWARDS THE ENSEMBLE MEANS TO HELP MITIGATE THESE  
DIFFERENCES, THOUGH DID KEEP MINOR PIECES OF THE GFS AND CMC WHICH  
KEPT SOME SEMBLANCE OF A SYSTEM ACROSS THE SOUTHEAST EARLY NEXT  
WEEK.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
MOISTURE AHEAD OF THE STRONG COLD FRONT IN THE EAST WILL CONTINUE  
SHOWERS AND STORMS ALONG THE BOUNDARY ACROSS THE SOUTHEAST,  
MID-ATLANTIC, AND COASTAL NEW ENGLAND, WITH RAIN CHANGING TO SNOW  
LIKELY FOR NORTHERN AND INLAND REGIONS AS TEMPERATURES PLUMMET  
BEHIND THE COLD FRONT. MEANWHILE, STRONG DYNAMICS ALOFT AND COLDER  
AIR WRAPPING AROUND THE LOW SHOULD SUPPORT A WINTER STORM THREAT  
AND ACCUMULATING SNOWFALL SATURDAY INTO EARLY SUNDAY ACROSS  
PORTIONS OF THE INTERIOR NORTHEAST, ESPECIALLY NORTHERN VERMONT,  
NEW HAMPSHIRE, AND MAINE. AS THE LOW PRESSURE DEEPENS RAPIDLY ON  
SATURDAY, GUSTY WINDS ARE LIKELY TO ACCOMPANY THE SYSTEM ACROSS  
MUCH OF THE EASTERN STATES, WITH WINDS CONTINUING INTO SUNDAY AS  
WELL FOR NEW ENGLAND AS THE STORM QUICKLY PULLS AWAY. BEHIND THE  
FRONT, MUCH BELOW NORMAL TEMPERATURES ARE EXPECTED FROM THE LOWER  
MISSISSIPPI VALLEY THROUGH THE OHIO VALLEY ON SATURDAY, AND INTO  
MUCH OF THE EAST BY SUNDAY, WITH DAYTIME HIGHS 20-30 DEGREES BELOW  
NORMAL IN SOME PLACES. EVEN FOR PARTS OF NORTHERN FLORIDA AND THE  
SOUTHEAST, LOW TEMPERATURES SUNDAY MORNING COULD BE NEAR OR BELOW  
FREEZING WITH RECORD LOWS POSSIBLE IN SOME LOCATIONS.  
 
MEANWHILE, RAIN AND MOUNTAIN SNOWS ARE LIKELY ACROSS THE NORTHWEST  
NEXT WEEKEND WITH THE PASSAGE OF THE FIRST SHORTWAVE. THE NEXT  
TROUGH EARLY NEXT WEEK LOOKS POISED TO DIRECT A POSSIBLE  
ATMOSPHERIC RIVER TOWARDS THE PACIFIC NORTHWEST WITH HEAVY RAIN  
AND HIGHER TERRAIN SNOW POSSIBLE ACROSS WESTERN WASHINGTON/OREGON  
AND NORTHERN CALIFORNIA, WITH ADDITIONAL SNOWFALL FARTHER INLAND  
ACROSS THE NORTHERN ROCKIES. UPPER LEVEL RIDGING AHEAD OF THIS  
WILL BUILD ACROSS THE CENTRAL U.S. WITH DAYTIME HIGHS 10 TO 20+  
DEGREES ABOVE NORMAL BY NEXT TUESDAY FOR THE NORTHERN/CENTRAL  
PLAINS, WHICH SHOULD BE A WELCOME RELIEF TO THE VERY CHILLY  
WEATHER EXPECTED LATER THIS WEEK. RAIN CHANCES SHOULD ALSO  
INCREASE AGAIN OVER THE GULF COAST AND SOUTHEAST NEXT  
MONDAY-TUESDAY.  
 
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  
 
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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