ChescoWx

This will no doubt verify 6 in along southern Chesco to I think that is 20 over me....

Just want to be sure everyone on here knows sleet counts as snow.....it just accumulates slower. When measuring tomorrow you should measure the snowfall when it changes to sleet/IP and then measure the sleet accumulation in inches. If it goes back to snow clean the board and start over. You then add the 3 together to get the total snow total. No doubt most know this but want to be sure

18z NAM much more in line now with GFS Euro.....makes more sense

Kutchera from 12z Euro

Sleet of course does accumulate and counts as snow just a heck of lot slower to accumulate...and shovel LOL! WXSIM now clearly seeing the IP mixing occurring - currently with 12z GFS and NAM it has S+ for NW Chesco by 230pm with a turn to heavy IP by 530pm - with 3" of snow at that point then it shows the heavy IP accumulating an additional 1.5" of snow/IP by 1130pm over a 6 hour period....then back to S+ till 6am with total snow accumulation of 13.2"

Of course we don't shovel or scrape a model run....stay tuned it will change

Wednesday: Mostly cloudy to cloudy in the morning, becoming dense overcast in the afternoon. A slight chance of snow in the morning, then snow likely in the afternoon. High 35. Wind chill ranging from 19 to 26. Wind east-northeast around 7 mph, gusting to 16 mph, in the morning, becoming 10 mph, gusting to 18 mph, in the afternoon. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly between a quarter and half an inch. Snow accumulation 2 to 3 inches. Wednesday night: Dense overcast. Patchy light fog after midnight. Snow likely. Breezy. Low 28. Wind chill as low as 18. Wind east-northeast around 14 mph, gusting to 20 mph, in the evening, becoming 11 mph, gusting to 20 mph, after midnight. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around 2 inches. Snow accumulation 15 to 20 inches. Thursday: Cloudy. A chance of a mix of snow and sleet in the morning, then a slight chance of snow in the afternoon. High 30. Wind north-northeast around 9 mph, gusting to 18 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 or ice (on ground) accumulation about an inch.

WXSIM with 18z GFS NAM has 13" to 18" of snow for Western Chesco.....it has 850's warming to 30.6 at 2am at their warmest....hence the inflated totals..... Wednesday: Cloudy in the morning, becoming dense overcast in the afternoon. A slight chance of snow in the morning, then snow likely in the afternoon. High 35. Wind chill ranging from 21 to 25. Wind northeast around 7 mph, gusting to 15 mph, in the morning, becoming 11 mph, gusting to 19 mph, in the afternoon. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around a quarter of an inch. Snow accumulation 1 to 2 inches. Wednesday night: Dense overcast. Snow likely. Breezy. Low 29. Wind chill as low as 18. Wind northeast around 14 mph, gusting to 21 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around 2 inches. Snow accumulation 12 to 16 inches.

Of note In 126 years of December records in Chester County only 26 storms have exceeded 6" only on average once every 5 years! Only 2x has a December storm exceeded 20" - six times 12" plus and only 8 times 10" or more....climo argues against a major snow event....but of course that does not mean it cannot happen....just rare!

Gonna be dicey IMO for most on here unless N and W of MDT - RDG - ABE line.......

I always like to start looking at the NAM for the profiles at this juncture....growing pretty confident the 850's get to over 0c over much of the area for a time on Wednesday night before crashing SE again....with that in mind thinking a early thump of snow to IP for a while and back to snow before ending with a solid 6" to 9" of snow/concrete snow in my area of NW Chesco.....the all snow zone will be from around MDT to just N of RDG to just N of ABE and NE from there.....but allow me the option to change my forecast by game time!

WXSIM backing off a bit on totals with 12z runs only 14" to 19" now.... Wednesday: Cloudy in the morning, becoming dense overcast in the afternoon. A slight chance of snow in the morning, then snow likely in the afternoon. High 33. Wind chill around 21. Wind east-northeast around 8 mph, gusting to 16 mph, in the morning, becoming 11 mph, gusting to 18 mph, in the afternoon. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around a quarter of an inch. Snow accumulation 1 to 2 inches. Wednesday night: Dense overcast. Snow likely. Breezy. Low 29. Wind chill as low as 18. Wind east-northeast around 14 mph, gusting to 22 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around 2 inches. Snow accumulation 12 to 16 inches. Thursday: Dense overcast. Patchy light fog. Snow likely in the morning, then a chance of snow in the afternoon. High 30. Wind chill around 22. Wind northeast around 6 mph, gusting to 16 mph. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around a quarter of an inch. Snow accumulation about an inch.

Snowing almost moderately temp down to 34.4 on VP and 32.9 on Tempest...ground whitening quickly now

Rain Snow mix here in NW Chesco at 685ft temp 38.2 on VP and 36.9 on tempest....

I do not see this at all as a Miller B or any type of hybrid B system....there is no primary going up well west with a 2nd low developing on the coast

With KamuSnow's correction - thanks!!- with my miss of 1989....I went back and reran the report with over 1" of snow on the ground in Chester County on Christmas morning - thanks!

Kamu! You are 100% correct! I somehow missed 1989....I am going back and reviewing all years - it snowed 3.1 inches in Chesco on the 8th with additional smaller snow events on the 12th/13th/15th and 19th keeping snow on the ground through the rest of the month. I will update and include 1989 - thanks!! Paul

WXSIM much more enthused about tomorrow's initial event than my NWS point and click is.....WXSIM sees a mix of rain and snow becoming all snow and briefly heavy after 230pm with 2" to maybe 3" accumulating. It has "backed off" a bit on the Wed event starting around 2pm with 19.4" of snow accumulating....

WXSIM with 6z data shows 850s getting to 32.7 by 11pm Wed night with a mix of heavy snow and sleet.....still spits out 26.8" of snow and sleet - on top of the 2" or so tomorrow PM.... Wednesday: Cloudy in the morning, becoming dense overcast in the afternoon. Snow likely in the afternoon. High 35. Wind chill around 23. Wind east-northeast around 8 mph, gusting to 18 mph, in the morning, becoming 12 mph, gusting to 19 mph, in the afternoon. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around a quarter of an inch. Snow accumulation 1 to 2 inches. Wednesday night: Dense overcast. Snow likely in the evening, then a mix of snow and sleet likely after midnight. Breezy. Low 30. Wind chill as low as 20. Wind east-northeast around 13 mph, gusting to 23 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around 3 inches. Snow or ice (on ground) accumulation 20 inches or more.

12z NAM shows 4" of snow tomorrow PM......

There will be a couple more of these 18z type runs - details to be ironed out....when the EPS is honking I am buying at least a significant snowstorm (over 6") for many from the I95 corridor N and W....keep in mind major 10" + storms are very rare in this area. I will be posting top 10 shortly for Western Chester County PA shortly