ChescoWx

A few flakes started falling at 10am - still just a few flurries Temp VP 26.4 / DP 15.2 Tempest 25.2/ 12.4 - the tempest always seem to run at least a degree colder than the VP

Last WXSIM with 6z data before storm time - has total snow of 14" to 23" Today: Dense overcast. A slight chance of snow in the morning, then snow likely in the afternoon. High 30. Wind east around 3 mph. Chance of precipitation 60 percent. Precipitation (liquid equivalent) mostly less than a quarter of an inch. Snow accumulation 1 to 2 inches. Tonight: Dense overcast. Snow likely in the evening, then a mix of snow, sleet, and rain likely after midnight. Low 25, but temperatures rising after midnight. Wind chill as low as 16. Wind east around 11 mph, gusting to 17 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly between half an inch and one inch. Snow or ice (on ground) accumulation 3 to 5 inches. Monday: Dense overcast. A mix of snow and sleet likely. Breezy. High 33. Wind chill around 20. Wind east-northeast around 14 mph, gusting to 21 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly between 1 and 2 inches. Snow or ice (on ground) accumulation 8 to 12 inches. Monday night: Dense overcast. Snow likely in the evening, then a chance of snow after midnight. Breezy. Low 29. Wind chill as low as 19. Wind north-northeast around 13 mph, gusting to 20 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around half an inch. Snow accumulation 2 to 4 inches.

All of the 6z runs in one spot for your viewing pleasure - I will take the Icon please...

That was of course a totally different set up...all elevation driven as about 6 miles NW of me had 50" in Morgantown at 625 ft while only 19" fell 300 feet lower down in Coatesville at 325ft asl....

Growing increasingly confident that the CCB and axis of heaviest snow will be NE of the PHL area.....this makes the most sense with a Miller B event....

This will be the storm where folks waiting for the 2nd to form during the dry slot will say radar looks like crap etc. - storm fail etc. That is why for snow weenies Miller B's are painful.....and unpredictable

My 1st Call Forecast for the area

1st couple 12 z runs

During that lull pre-coastal ramp up is when folks will get nervous....then think the 2nd forms a bit further NE than current models - limiting snow in our area but really hitting North Jersey and CT etc.

More of an ENE track....

We are certainly at the highest snow guidance at this point...there is nowhere to go but lower from here....I suspect many will be disappointed as I think reality is less than 10" for most...

Latest WXSIM with 6z NAM/GFS blend coming up with a "plowable" event for NW Chester County PA to the tune of 24" to 34"....sounds reasonable right? Snow starts 7am Sunday and ends at 1am Wednesday - This might be the highest snow forecast WXSIM has ever produced....verification likelihood....nada! Sunday: Dense overcast. A slight chance of snow in the morning, then a chance of snow in the afternoon. High 31. Wind chill around 22. Wind east around 2 mph in the morning, becoming 5 mph in the afternoon. Chance of precipitation 60 percent. Precipitation (liquid equivalent) mostly less than a quarter of an inch. Snow accumulation 1 to 2 inches. Sunday night: Dense overcast. Snow likely. Low 26, but temperatures rising after midnight. Wind chill as low as 17. Wind east around 9 mph, gusting to 15 mph, in the evening, becoming 13 mph, gusting to 20 mph, after midnight. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around an inch. Snow accumulation 6 to 10 inches. Monday: Dense overcast. Snow likely. Windy. High 33. Wind chill around 20. Wind east around 16 mph, gusting to 24 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly between 2 and 3 inches. Snow accumulation 15 to 20 inches. Monday night: Dense overcast. Snow likely in the evening, then a chance of snow after midnight. Breezy. Low 29. Wind chill as low as 20. Wind northeast around 13 mph, gusting to 22 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly between a quarter and half an inch. Snow accumulation around 2 inches. Tuesday: Dense overcast in the morning, becoming cloudy in the afternoon. A chance of snow in the morning, then a slight chance of snow in the afternoon. Breezy. High 31. Wind chill around 20. Wind north around 12 mph, gusting to 21 mph. Chance of precipitation 50 percent. Precipitation (liquid equivalent) mostly around a tenth of an inch. Snow accumulation about a quarter inch.

Barely made it to the teens at 19.2 this AM in the higher spots of NW Chesco...only our 2nd time all season. On today's date in 1966 we received an additional 1" of snow combined with the 13" on the 29th in recording at 14" our 32nd largest snowstorm since records began in 1894

Yep 20" in NW Chesco ....lock it up - that won't change

18z WXSIM with a NAM/GFS blend has snow starting by 1pm Sunday with snow totals of 20" to 29"...um no....not happening! Sunday: Dense overcast. A slight chance of snow in the morning, then a chance of snow in the afternoon. High 32. Wind chill ranging from 22 to 26. Wind southeast near calm in the morning, becoming 6 mph, gusting to 16 mph, in the afternoon. Chance of precipitation 50 percent. Precipitation (liquid equivalent) mostly around a tenth of an inch. Snow accumulation about half an inch. Sunday night: Dense overcast. Snow likely. Breezy. Low 28. Wind chill as low as 19. Wind east around 11 mph, gusting to 17 mph, in the evening, becoming 14 mph, gusting to 21 mph, after midnight. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around an inch. Snow accumulation 5 to 8 inches. Monday: Dense overcast. Snow likely. Windy. High 33. Wind chill around 20. Wind east around 17 mph, gusting to 26 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly between 1 and 2 inches. Snow accumulation 12 to 16 inches. Monday night: Dense overcast. Snow likely in the evening, then a slight chance of snow after midnight. Breezy. Low 30. Wind chill as low as 21. Wind north-northeast around 13 mph, gusting to 21 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly between half an inch and one inch. Snow accumulation 3 to 5 inches.

See latest GFS below...I am not buying what it is selling. I really think this is a PHL NE special with a sharp cutoff across N and W areas. Plowable snow for many sure....over 19" at MDT - no and over a foot in NW Chesco.....no

Couple of the 1st 12z runs - shows the down side on the NAM of Miller B's for those in the NW burbs.....not saying either of these will verify....but still not baked that is for sure!

6z WXSIM with a NAM/GFS Blend - starting time light snow by around 1pm with S+ by 4pm ending by 7pm Monday eve. with 11" to 14" of snow Sunday: Dense overcast. A slight chance of snow in the morning, then a chance of snow in the afternoon. High 34. Wind chill ranging from 23 to 27. Wind east-northeast around 3 mph in the morning, becoming east-southeast around 7 mph, gusting to 16 mph, in the afternoon. Chance of precipitation 60 percent. Precipitation (liquid equivalent) mostly less than a quarter of an inch. Snow accumulation about an inch. Sunday night: Dense overcast. Snow likely. Breezy. Low 28, but temperatures rising after midnight. Wind chill as low as 19. Wind southeast around 11 mph, gusting to 17 mph, in the evening, becoming east-northeast around 14 mph, gusting to 21 mph, after midnight. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around an inch. Snow accumulation 5 to 8 inches. Monday: Dense overcast. Snow likely. Windy. High 33. Wind chill around 20. Wind east-northeast around 16 mph, gusting to 25 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around an inch. Snow accumulation 5 to 8 inches.

A few of the 6z snow maps in one spot for those interested - note NAM is only thru 1pm Monday Quote Average Chester County PA Snow at elevations over 660 FT ASL (1983-Present) = 35.6": Winter 2020/21 - (5) Winter Events so far with total Current Seasonal Snowfall to date at 11.2" : 01/3 - 1.0" /12/2 (0.3") / 12/9 (0.3") / 12/16-17 (9.3") / 12/25 (0.3") 2019/20 snow (5.8" )/ 2018/19 snow (35.1" )/ 2017/18 snow (58.5") / 2016/17 snow (24.0")/ 2015/16 snow (40.8")/ 2014/15 snow = (55.3") /2013/14 snow (80.0") . PHL Heat Island factoid 2016-20 = 169 days at 90+ while KMQS/KPTW and East Nantmeal combined 121 days! Check out my historical Western Chester County PA website at https://www.chescowx.com and follow me on https://twitter.com/ChescoWx

On this date in Chester County back in 1922 we were in the middle of our 9th biggest snowstorm in county history with 26" in total falling with 8"on today's date after the record daily 18" on the 28th. AM low today only 20.5 - still only 1 time in the teens all season!