ChescoWx

Agreed Steve....more likely than not hence NWS high % chances this far out....that said I expect a slow arrival due to mighty low DPs....plus I suspect for the coastal plain some mixing issues and even back a bit NW of the fall line. Looks a lot to me like a typical storm with mixing in the City and SJ and increasing amounts N and W, Sort of like storms of my youth

Still ice on trees and the deck - temp up to 33.3 but no melting yet

Quite a bit more ice than I expected today....still holding at 32.8 on VP and 31.8 on Tempest - trees are pretty weighted down in back

Moderate sleet shower just passed through across NW Chester County as of 1042am temp 30.6

A mix of IP and ZR in East Nantmeal 31.4/22.8 on VP and 30.2/22.3 on the Tempest

I will start this party off - a few very light snow flakes just starting to fall here in East Nantmeal in NW Chester County PA 32.3/19.2

Keep the faith- what happens in December the winter remembers!! Near normal snow for all this season!!!

Yesterday was only out 2nd below normal day this month...the last being on New Year's day

Latest WXSIM Forecast is only a wee bit different with the 18z model data compared to the 6z data from this AM! This is why I love some folks on here who get fired up with a WXSIM forecast....when it is really only represents a hyper local output for NW Chester County PA... it's a simple regurgitation of a GFS/NAM blend that changes from run to run. I always try to tell folks that models or programs like WXSIM are never a true forecast...only an output of an imperfect numerical model attempting to inform a true weather professional of what 1 or 2 models of the many at a weather professional disposal are as they try to use all available data to make a true forecast for any given site. All of that said....the 18z forecast is not going to be correct.....reality will be something else....could we be NAMMED on the next run or tomorrow at 12z - of course. Key point stay tuned - lots of storms or at leas rumor of storms on the table for the foreseeable future - interesting times ahead - keep the faith! Monday night: Dense overcast. A chance of a mix of sleet, rain, and snow after midnight. Low 32. Wind east-northeast around 2 mph in the evening, becoming 6 mph after midnight. Chance of precipitation 30 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. No snow or ice (on ground) accumulation expected. Tuesday: Dense overcast in the morning, becoming cloudy in the afternoon. A chance of a mix of rain, sleet, and snow in the morning, then a chance of rain in the afternoon. High 39. Wind east-northeast around 8 mph. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around a quarter of an inch. No snow or ice (on ground) accumulation expected. Tuesday night: Dense overcast in the evening, becoming cloudy after midnight. A chance of rain. Low 35. Wind east-northeast around 2 mph in the evening, becoming north-northwest after midnight. Chance of precipitation 50 percent. Precipitation mostly around a tenth of an inch. Wednesday: Cloudy. Relatively mild. High 43. Wind north around 4 mph. Wednesday night: Cloudy in the evening, becoming dense overcast after midnight. A slight chance of rain in the evening, then a chance of a mix of rain and snow after midnight. Low 33. Wind chill ranging from 25 to 37. Wind north-northeast around 5 mph in the evening, becoming 8 mph, gusting to 17 mph, after midnight. Chance of precipitation 50 percent. Precipitation (liquid equivalent) mostly less than a quarter of an inch. Little or no snow accumulation expected. Thursday: Dense overcast in the morning, becoming cloudy in the afternoon. Snow likely. Breezy. High 35. Wind chill around 24. Wind north-northeast around 15 mph, gusting to 25 mph. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around a quarter of an inch. Snow accumulation 1 to 2 inches.

For your entertainment....with 6z data the WXSIM has quite the wintry week in store - snow arriving by 930pm on Monday night - becoming briefly moderate around the 1am to 3am time frame then continuing lightly for much of the day on Tuesday as a mix of snow and sleet - total snow/IP accumulation by Wed AM about 2". Then it shows off and on mixed precip for Wed before heavy snow begins on Thursday around 7AM with falling temps through the day before snow tapers off by 10pm....but not before 14" to 18" of snow has fallen.

Good to have you back on this forum back down here....not a bad forecast at this point IMHO....but as we know - this will in all likelihood change

Hey guys, Below is the 12z GFS - now I am not buying what this is selling as I think it is counting IP as snow in it's 10:1 calculation. That said I am inclined to like the 0z Euro Ensembles with paint a more general 3" to 6" across most spots north of the M/D line.

Really liking a solid 3" to 6" for much of the area - as NWS said this morning the warm layer will be shallow so might be a case of snow or IP with rain further south. In these cases the snow can overcome the thin warm layer....

Still only 1 day all season with a temp below 20 degrees...of course many lower spots have had many more this season, 20.5 here and 21 and KMQS this AM

My earlier post had an error on monthly avg - correction below

We are now at below normal seasonal snow to date for the 1st time since December 16th

Of course most spots including here in Chester County are still at above normal snowfall for the season to date.... which in a year which should end up with below normal snow....is not a bad thing. We are not done with snow this season....keep the faith!

Euro ensembles for me the go to says - snow is coming before month's end

I have gone back and analyzed long running data now for both long term Chester County sites and have now updated to include both West Chester PA and Coatesville PA. Clearly West Chester and Coatesville are well aligned for 12 decades....and almost exactly the same over the last 2 decades....however, PHL is just as clearly demonstrating the heat island problem as they begin to accelerate away - not at all consistent.

I went back and updated the analysis for the last 12 decades now including the Philadelphia data from 1900-1949 (this represents raw unadjusted data with no after the fact adjustments) comparing data for the last 120 years from 1900 thru 2019. The key finding is that the suspected rapid PHL heat island impact and problems are growing at an even greater rate than ever imagined....the difference between the heat island near Philadelphia and the burbs using actual NWS observed temps is telling....Just look at how quickly the lines are diverging and you will see where this is going. Just look at that % difference column and you can see the disparity between average temperatures has never been higher and is only getting more pronounced.

I ran a comparison between my Davis VP - Ambient WS-2902A - Tempest and KMQS - see below