ChescoWx

The sleet and now ZR looks to be winding down - total snow and sleet accumulation 2.0". Plus a nice glaze (see pix) with the ZR. Current temp 31.4

Road in poor shape here in NW Chester County Pa with sleet we may get our snow total up to 2" with this event Continues to sleet with a few flakes mixed in with heavier precip temp up to 27.4

With our 1.8" of snow/sleet so far this is our "biggest" event of our winter season so far. Depending if we stay sleet with the next band maybe we can pass the 2" snow/sleet mark with this one. Of note we have now had 3.6" of snow so far here in January only 1.4" below normal 5.0" through today. Seasonal snowfall is at 5.6" exactly 50% of our normal of 11.2" through today. Yet I received a message from a twitter follower today asking me why we are so low in snow this January against normal....I replied and told him we are one major snow event from being above normal for the season....stay tuned! Currently here in East Nantmeal the sleet is getting heavier and as the IP gets heavier some more flakes are mixing in - temp continues to slowly rise up 1 degree in last hour and up to 26.5

Hey Mike great question and not trolling for sure....keep in mind the WXSIM is only as good as the models being used - in this case it is a simple mix of the NAM and GFS....all models have been mighty poor this season especially days in advance. The WXSIM relies on the quality of these models if it's garbage in it's garbage out. What is is good for is nailing very local specifics to my backyard. Temps, start time of precip etc. as the models get better within 24 hours so does WXSIM. Does that make sense? Paul

East Nantmeal Township Chester County PA Sleet mix began at 230pm lighter now still some mangled flakes Snow/Sleet so far 1.8" at 3pm obs Temp 25.0 DP 20.0

Latest WXSIM with 6z - looks like WXSIM is winning for now the great battle vs NWS temp wise....NWS has now moved my P&C to 32 degree high - WXSIM still colder. Today: Dense overcast. A slight chance of a mix of snow and sleet in the morning, then sleet likely in the afternoon. High 27. Wind south near calm in the morning, becoming 6 mph in the afternoon. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly between a quarter and half an inch. Snow or ice (on ground) accumulation about half an inch. Tonight: Dense overcast in the evening, becoming cloudy after midnight, with scattered light frost possible. A mix of snow and sleet likely in the evening, then a slight chance of freezing rain after midnight. Low 25, but temperatures rising after midnight. Wind chill ranging from 16 to 24. Wind south-southwest around 9 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around half an inch. Snow or ice (on ground) accumulation 2 to 3 inches. Little if any freezing rain accumulation.

WXSIM with 18z GFS/NAM backing off on the snow but hitting sleet harder - thus reducing snow/sleet totals by about an inch - total now 2" to 3" at most - however as I mentioned early this AM I am not surprised NWS brought the WWA down into Western Chester County with their 4pm update - the fascinating (to me) big battle tomorrow will be on temps - the NWS P&C has me at 37 while WXSIM only 26.....very rare to see that large spread between WXSIM and NWS...who will win the great battle of NW Chesco weather??? stay tuned!! Saturday: Cloudy in the morning, becoming dense overcast in the afternoon. A slight chance of snow in the morning, then a mix of sleet and snow likely in the afternoon. High 26. Wind south near calm in the morning, becoming 7 mph in the afternoon. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around half an inch. Snow or ice (on ground) accumulation 1 to 2 inches. Saturday night: Dense overcast in the evening, becoming mostly cloudy to cloudy after midnight, with scattered light frost possible. A mix of sleet, snow, and freezing rain likely in the evening, then a slight chance of a mix of freezing rain and sleet after midnight. Low 24, but temperatures rising after midnight. Wind chill ranging from 15 to 21. Wind south-southwest around 9 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around half an inch. Snow or ice (on ground) accumulation about an inch. Little if any freezing rain accumulation.

Just looked closer at the 18z GFS....that may be the strangest snow map I have ever seen for a non-Miller B event - verification chances.....I would not bet a lot on that

I suspect that will not be happening.....

WXSIM with 12z data again ticked a bit colder and a little more snow/sleet accumulation with a bit earlier start time - total snow sleet 3.5" to 4.5" Here is the rundown: 10am snow arrives temp (22.2) 1pm Moderate IP (23.6) 4pm Heavy IP (23.4) 7pm Heavy Snow (23.6) Snow ends around 8pm

Keep in mind sleet counts as snow - it just accumulates relatively slow with a rule of thumb rate of w.e. to sleet of only 5:1 vs snow which is 10:1

My current thoughts (crude as it may be) on the upcoming event

Latest WXSIM with 6z NAM/GFS data has trended colder for NW Chester County I'm a bit surprised my zone forecast does not include a WWA. It could be the NWS cannot split the zone north vs. south. My point and click has a high of 37 for me tomorrow in East Nantmeal... I will take the way under - I will be surprised if we get near or above freezing. Total snow and sleet accumulation around 2" to 3". Here is the rundown of precipitation types temperatures and timing 12 noon Light snow (temp) (25.3) 1pm Moderate sleet (24.7) 4pm Heavy sleet (23.6) 7pm Heavy snow (23.6) 8pm snow ending (23.9)

I told my wife to never look at TV weather...we can see the models just as well....funny thing is that forecast she shows tonight will be the same one they go with all morning tomorrow

WXSIM with 0z NAM and 18z GFS for NW Chesco - 3" to 5" of snow/sleet Saturday: Cloudy in the morning, becoming dense overcast in the afternoon. A slight chance of snow in the morning, then a mix of snow and sleet likely in the afternoon. High 29. Wind south around 2 mph in the morning, becoming 8 mph in the afternoon. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around half an inch. Snow or ice (on ground) accumulation around 2 inches. Saturday night: Cloudy in the evening, becoming mostly cloudy to cloudy after midnight, with scattered light frost possible. Snow likely in the evening, then a slight chance of a mix of sleet, freezing rain, snow, and rain after midnight. Low 25, but temperatures rising after midnight. Wind chill ranging from 15 to 20. Wind south-southwest around 10 mph, gusting to 16 mph. Chance of precipitation 60 percent. Precipitation (liquid equivalent) mostly less than a quarter of an inch. Snow or ice (on ground) accumulation 1 to 2 inches. Little if any freezing rain accumulation.

Picked up 0.3" of snow with the squall that came through around 10pm temp down to 30.5

WXSIM with 12z NAM/GFS data trended a bit snowier but still mainly sleet with temps never rising above freezing in NW Chester County PA during the storm. Timing - Snow arrives by 1230pm briefly heavy before changing to IP by 2pm then IP heavy at times before mixing back with snow by 6pm and ending by 730pm - total snow/sleet accumulation 3" to 4"

Keep in mind NAM at this range not real useful with qpf....it will NAM someone by Saturday 0z run

From that many days out and always WXSIM is only as good as the GFS and NAM at that range.- models suck this year!!..good to see it closing in closer to reality as we draw closer!

WXSIM continues the trend toward a sleet fest for NW Chesco....I suspect areas northeast bound toward ABE will have a plowable snow/sleet amount greater than 3" before znizzle or drizzle Saturday: Dense overcast. A chance of a mix of snow and sleet in the morning, then sleet likely in the afternoon. High 31. Wind chill around 18. Wind south-southeast around 5 mph, gusting to 16 mph, in the morning, becoming 13 mph, gusting to 20 mph, in the afternoon. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around an inch. Snow or ice (on ground) accumulation 1 to 2 inches. Saturday night: Cloudy in the evening, becoming partly cloudy after midnight. A mix of rain, freezing rain, and sleet likely in the evening, then a slight chance of rain after midnight. Breezy. Low 31, but temperatures rising after midnight. Wind chill ranging from 20 to 30. Wind south around 13 mph, gusting to 19 mph, in the evening, becoming west-southwest after midnight. Chance of precipitation 60 percent. Precipitation (liquid equivalent) mostly around a quarter of an inch. Little or no ice (on ground) accumulation expected. Above-ground freezing rain accumulation up to 0.1 inches.

Latest Wxsim for Chester County PA a sleet fest with up to 4" of snow/sleet total.... Saturday: Dense overcast. A slight chance of snow in the morning, then sleet likely in the afternoon. High 30. Wind chill ranging from 13 to 20. Wind south-southeast around 6 mph, gusting to 17 mph, in the morning, becoming 12 mph, gusting to 18 mph, in the afternoon. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around 2 inches. Snow or ice (on ground) accumulation 2 to 4 inches. Saturday night: Cloudy in the evening, becoming partly to mostly cloudy after midnight. A mix of rain, snow, sleet, and freezing rain likely in the evening, then a slight chance of rain after midnight. Breezy. Low 30, but temperatures rising after midnight. Wind chill ranging from 18 to 29. Wind south around 12 mph, gusting to 19 mph, in the evening, becoming west-southwest after midnight. Chance of precipitation 60 percent. Precipitation (liquid equivalent) mostly around a quarter of an inch. Snow or ice (on ground) accumulation about half an inch. Little if any freezing rain accumulation.

Wxsim looks a bit tamer now with 3" to 6" of snow/IP - it will change as the models move....stay tuned! Saturday: Dense overcast. A slight chance of snow in the morning, then a mix of sleet and snow likely in the afternoon. High 32. Wind chill around 19. Wind south-southeast around 6 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 between 1 and 2 inches. Snow or ice (on ground) accumulation 2 to 4 inches. Saturday night: Dense overcast in the evening, becoming mostly cloudy to cloudy after midnight. A mix of snow and rain likely in the evening, then a slight chance of a mix of rain and snow after midnight. Low 30, but temperatures rising after midnight. Wind chill ranging from 20 to 28. Wind south around 11 mph, gusting to 23 mph, in the evening, becoming west-southwest after midnight. Chance of precipitation 80 percent. Snow accumulation 1 to 2 inches.

Latest Wxsim for next weekend with 12z NAM/GFS combo - of course we don't shovel model snow!! Saturday: Dense overcast. A chance of snow in the morning, then a mix of sleet and snow likely in the afternoon. High 31. Wind chill ranging from 11 to 18. Wind east-southeast around 7 mph, gusting to 16 mph, in the morning, becoming 10 mph, gusting to 18 mph, in the afternoon. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly around 2 inches. Snow or ice (on ground) accumulation 12 to 16 inches. Saturday night: Cloudy in the evening, becoming mostly cloudy after midnight. Patchy light fog in the evening. A chance of a mix of freezing rain, sleet, and snow in the evening, then a slight chance of a mix of rain and snow after midnight. Low 30, but temperatures rising after midnight. Wind chill ranging from 19 to 29. Wind south around 10 mph, gusting to 20 mph, in the evening, becoming west-southwest after midnight. Chance of precipitation 60 percent. Precipitation (liquid equivalent) mostly less than a quarter of an inch. No snow or ice (on ground) accumulation expected. Little if any freezing rain accumulation.

Looking ahead to next weekend the WXSIM has light snow arriving by 7pm Friday night becoming all sleet by 10pm with heavy sleet at times through mid morning than becoming ZR in the PM and finally all rain by 4pm - total snow (mainly sleet) accumulation 3" to 4" - temps than plummet on Sunday with a low Monday AM of just 5 degrees with a high on Monday of 13 above

For our 2nd straight day a record high...and this time an all-time all elevation Chester County record of 64.4 at 1:44am besting the old mark of 61.8 set just 3 years ago. Also recorded 0.35" of rain with the frontal passage with a high wind gust of 24mph