483  
FXUS02 KWBC 071858  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
157 PM EST MON NOV 07 2022  
 
VALID 12Z THU NOV 10 2022 - 12Z MON NOV 14 2022  
 
...POTENTIALLY SIGNIFICANT WINTER STORM LIKELY FOR THE NORTHERN  
PLAINS ON THURSDAY...  
 
...NICOLE TO IMPACT FLORIDA AND THE EAST COAST LATER THIS  
WEEK/WEEKEND...  
 
   
..OVERVIEW
 
 
AN AMPLIFIED UPPER TROUGH CENTERED OVER THE ROCKIES EARLY THURSDAY  
SHOULD DEVELOP INTO A CLOSED LOW OVER THE UPPER MIDWEST/GREAT  
LAKES BY EARLY FRIDAY. CONFIDENCE CONTINUES TO INCREASE FOR A  
POTENTIALLY SIGNIFICANT WINTER STORM TO DEVELOP OVER PARTS OF THE  
NORTHERN PLAINS WITH LIKELY APPRECIABLE ACCUMULATING SNOWFALL AND  
STRONG WINDS THURSDAY INTO FRIDAY, THOUGH WITH CONTINUED  
UNCERTAINTY FOR THE SPECIFICS. MEANWHILE, UPPER LEVEL RIDGING WILL  
CONTINUE THURSDAY INTO FRIDAY ACROSS PARTS OF THE EASTERN U.S.  
BEFORE WHAT IS NOW SUBTROPICAL STORM NICOLE (LIKELY TROPICAL BY  
THE MEDIUM RANGE PERIOD) REACHING FLORIDA IS LIKELY TO GET PICKED  
UP AHEAD OF THE APPROACHING ROCKIES/PLAINS TROUGH. NICOLE WILL  
LIKELY BRING WIDESPREAD HEAVY RAINFALL AND GUSTY WINDS TO PARTS OF  
FLORIDA THURSDAY AND SPREADING UP THE EASTERN SEABOARD FRIDAY AND  
SATURDAY. A REBUILDING UPPER RIDGE OVER THE NORTHEAST  
PACIFIC/NORTHWESTERN NORTH AMERICA WILL LIKELY YIELD MEAN  
TROUGHING OVER MUCH OF CANADA INTO THE LOWER 48 BY THE WEEKEND AND  
EARLY NEXT WEEK, ALONG WITH BELOW NORMAL TEMPERATURES OVER MUCH OF  
THE COUNTRY.  
 
   
..GUIDANCE AND PREDICTABILITY ASSESSMENT
 
 
THERE IS STILL MEANINGFUL SPREAD FOR THE DEVELOPING NORTHERN TIER  
STORM DURING THE LATTER HALF OF THE WEEK, WITH LATEST GFS RUNS AND  
00Z ECMWF ON THE STRONGER AND/OR SOUTHWESTERN SIDE OF THE SPREAD  
AND THE 12Z UKMET FARTHEST NORTHEAST AS OF EARLY FRIDAY. THE NEW  
12Z ECMWF HAS TRENDED FARTHER NORTHEAST THAN ITS PRIOR RUN,  
HIGHLIGHTING THE CONTINUED UNCERTAINTY WITH IMPORTANT DETAILS.  
PREFERENCE SIDED WITH AN INTERMEDIATE SOLUTION BASED ON GUIDANCE  
AVAILABLE THROUGH THE 06Z CYCLE. AHEAD OF THIS SYSTEM, GUIDANCE  
SHOWS SOME SHUFFLING/TRENDING FOR SUBTROPICAL STORM NICOLE WHICH  
SHOULD GAIN A MORE TROPICAL CHARACTER IN COMING DAYS PER NATIONAL  
HURRICANE CENTER FORECASTS. 12Z GUIDANCE TRENDS ARE GENERALLY  
FASTER WITH THE NORTHWARD PROGRESSION OF NICOLE ALONG THE EAST  
COAST AS THE UPPER TROUGH APPROACHES.  
 
FARTHER WEST, MODELS AND ENSEMBLE MEMBERS ARE ALL OVER THE PLACE  
FOR EXACTLY HOW INITIAL EASTERN PACIFIC SHORTWAVE ENERGY MAY SPLIT  
TO PRODUCE ONE OR MORE PACIFIC UPPER LOWS/SHORTWAVES (WHICH MAY OR  
MAY NOT REACH THE WEST COAST), WITH THE REST OF THE ENERGY  
ROUNDING A LARGER SCALE MEAN RIDGE AND DROPPING INTO SOUTHERN  
CANADA AND THE LOWER 48. THERE MAY ALSO BE A SOUTHERN STREAM THAT  
CARRIES SHORTWAVE ENERGY ACROSS THE EASTERN PACIFIC AND FAR  
SOUTHERN TIER U.S. THUS CONFIDENCE CONFIDENCE ULTIMATELY BECOMES  
QUITE LOW FOR SHORTWAVE DETAILS ACROSS MUCH OF THE EASTERN PACIFIC  
AND WITHIN THE BROAD MEAN TROUGH COVERING CANADA AND THE LOWER 48.  
 
THE UPDATED FORECAST STARTED WITH AN OPERATIONAL COMPOSITE AND  
SOME LOCALIZED MANUAL ADJUSTMENTS DURING THE FIRST PART OF THE  
PERIOD TO REFLECT PREFERENCES FOR THE NORTHERN TIER STORM AND  
OFFICIAL NHC TRACK FOR NICOLE. THEN THE BLEND TRANSITIONED TO  
ABOUT HALF MODELS AND HALF ENSEMBLE MEANS TO BALANCE THE  
INCREASING DETAIL UNCERTAINTY WHILE HOLDING ONTO SOME DEFINITION  
OF FEATURES WHERE FEASIBLE. RESULTING SPECIFICS NEAR THE WEST  
COAST FROM SATURDAY ONWARD DO NOT REFLECT ANY CONFIDENCE IN THAT  
SPECIFIC EVOLUTION, AND INDEED THE NEW RUNS HAVE CHANGED.  
 
   
..WEATHER/HAZARD HIGHLIGHTS
 
 
A WELL DEFINED SURFACE LOW LOOKS TO EMERGE OUT OF THE CENTRAL HIGH  
PLAINS ON THURSDAY AND DEEPEN AS IT MOVES INTO THE UPPER  
MISSISSIPPI VALLEY BY FRIDAY. WITH MODEL RUNS CONTINUING TO SHOW  
THE POTENTIAL FOR ACCUMULATING AND POSSIBLY SIGNIFICANT SNOWFALL  
ACROSS PARTS OF THE DAKOTAS AND FAR NORTHERN MINNESOTA THURSDAY  
INTO FRIDAY, THE PROBABILITIES IN THE WINTER WEATHER OUTLOOK FOR  
DAY 4 CONTINUE TO INCREASE GRADUALLY, WITH WIDESPREAD GREATER THAN  
70% PROBABILITIES FROM WESTERN-CENTRAL SOUTH DAKOTA INTO FAR  
NORTHERN MINNESOTA. DEPENDING ON STRENGTH OF THE LOW, GUSTY WINDS  
COULD ACCOMPANY SNOWFALL AND LEAD TO POSSIBLE BLIZZARD CONDITIONS  
AND DANGEROUS TRAVEL. AGAIN, WHILE A MEANINGFUL WINTER STORM OVER  
PARTS OF THE NORTHERN TIER CONTINUES TO BECOME MORE LIKELY, THE  
SPECIFICS IN THE PLACEMENT OF THE HEAVIEST SNOW AXIS REMAIN IN  
QUESTION AND ARE DEPENDENT ON THE EXACT LOW TRACK AND STRENGTH. IN  
THE WARM SECTOR OF THIS STORM, MODERATE TO HEAVY RAINFALL IS  
POSSIBLE ACROSS PARTS OF THE UPPER MIDWEST AND INTO THE GREAT  
LAKES, WITH A CHANCE FOR STRONG THUNDERSTORMS AS WELL. THERE COULD  
BE AN AXIS OF FREEZING RAIN AND/OR SLEET BETWEEN THE SNOW AND RAIN  
AREAS, BUT AGAIN DEPENDENT ON DETAILS OF THE LOW.  
 
COASTAL AND MARITIME IMPACTS THAT INCLUDE COASTAL FLOODING,  
TROPICAL STORM FORCE WINDS, HEAVY RAINFALL, ROUGH SURF, AND BEACH  
EROSION ARE POSSIBLE ASSOCIATED WITH NICOLE NEAR/OVER FLORIDA AND  
THE SOUTHEAST. THE DAYS 4 AND 5 EXPERIMENTAL EXCESSIVE RAINFALL  
OUTLOOKS DEPICT SLIGHT RISK AREAS FROM PARTS OF FLORIDA AND THE  
SOUTHEAST COAST (DAY 4) AND INTO THE EASTERN CAROLINAS/COASTAL  
MID-ATLANTIC (DAY 5) TO SHOW THE POTENTIAL FOR FLASH FLOODING FROM  
TROPICAL RAINS. THESE AREAS MAY HAVE TO SHIFT OR BE UPGRADED IN  
FUTURE FORECASTS DEPENDING ON RAINFALL AMOUNTS AND THE TRACK OF  
THE TROPICAL SYSTEM. MOISTURE FROM THIS SYSTEM SHOULD MOVE UP MUCH  
OF THE EAST COAST INTO THE WEEKEND THOUGH WITH MORE UNCERTAINTY IN  
THE AMOUNTS AND COVERAGE. AN APPROACHING COLD FRONT WILL LIKELY  
HELP TO PROVIDE SOME FOCUSED ENHANCEMENT OF RAINFALL.  
 
EXPECT MUCH OF THE WEST/ROCKIES INTO THE NORTHERN PLAINS TO SEE  
BELOW NORMAL TEMPERATURES THROUGH THE FIRST PART OF NEXT WEEK. THE  
COLDEST AIR WILL LIKELY BE ACROSS THE NORTHERN HIGH PLAINS AND  
PLAINS THURSDAY-SATURDAY WITH HIGHS IN THAT AREA UP TO 20-30F  
BELOW NORMAL. SOME LOCATIONS IN THE GREAT BASIN MAY SEE SIMILAR  
ANOMALIES. IN CONTRAST, WELL ABOVE NORMAL TEMPERATURES WILL  
PROGRESS FROM THE MIDWEST TO THE EAST COAST THURSDAY-FRIDAY WITH  
WIDESPREAD DAILY RECORDS FOR WARM LOWS POSSIBLE AND A HANDFUL OF  
RECORD HIGHS AS READINGS SOAR 15 TO 25 DEGREES ABOVE NORMAL. A  
STRONG COLD FRONT CROSSING THROUGH THIS REGION LATE THIS WEEK WILL  
USHER IN A MUCH COLDER AIRMASS, WITH HIGH TEMPERATURES BY THE  
WEEKEND IN THE MIDWEST AS MUCH AS 10 TO 20 DEGREES BELOW NORMAL.  
THE COOLER TEMPERATURES WILL ALSO REACH THE EAST THIS WEEKEND, AND  
SUNDAY-MONDAY LOOK TO BE NEAR OR BELOW NORMAL FOR ALMOST THE  
ENTIRE CONUS.  
 
RAUSCH/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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