Significant End of Week Snowstorm - Updates 8 am Wed.

Issues Regarding this Storm:

• Model Worship: some forecasters literally take the Euro model verbatim. It is a very good model. Esp. when in days 3-7. But inside 72 hours it’s pretty average, esp. in regards to details.  
• Model Rejection: Some forecasters will trash the GFS every opportunity they can. It is not great in days 3-7 that is for sure. But it is not bad when within 72 hours. And that is where we are.

 
My Best Guess (Fine-tuned details this evening):   

• Snow will not start until midnight or later Fri night/early Sat morning.
• Snow will continue Saturday into the first half of the night.
• Road closing/crippling snows SOMEWHERE BETWEEN Lancaster/York to Shenandoah Valley, Virginia of 2-3 feet. Locally higher possible.
• Shift of 30 miles north or south will make big difference due to sharp drop-off in snow amounts as one heads north.
• Very little snow north of NY-PA border and west of Hudson Valley. Northern New Englanders will wave goodbye to this one as it moves south of them. 

This shows the upper level support for storm. Significant east coast storms have a closed low that slows the storm. 

This shows the surface map Friday evening at 7 pm. Snow is just beginning. 

This shows the temperatures above the ground up at about 5000 feet. It shows this will be all snow. Look for the closed circle. The biggest snows are NW of that. 

This shows the surface map at Saturday evening at 7 pm. Snow is just ending. 24 hours of snow means potential for a lot of snow. 

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​By now, you are probably hearing about a snowstorm that is coming to our area at the end of this week. Well, it appears to be true. There are a number of factors to support this:

• It fits the pattern. I expected another significant storm and for it to be snow. This is why my forecast from Fri said snow for next Fri.  
• Every major model out there has it. All the ensembles of those models have it.  
• Extensive cold air in place supported by high pressure is and will be present.  

My current thinking:

• Low develops over Gulf States and moves toward Tennessee Friday.
• Secondary low develops along coast of SC.
• New low moves north toward Norfolk, VA.
• Low moves slowly east north east away from east coast by late Saturday.
• Snow begins late Friday. Snow ends by Saturday evening. 

At this time I do not see a way where we miss this entirely. When significant storms occur, most often modelling captures it early.. But the details will need to be worked out. Right now, that is the case with this system. Details will be better known by Wed evening. I will do a special post in it at that time. 

My Weather Points for the Next 7 Days:   

1. Cold: Daytime temps in the 20s all week. Mon – Tue being the coldest and slight moderation occurring late in week and into the weekend.
2. Snow: flurries and a snow shower possible Mon/Tue; some light snow Wed night (coating to 1”); significant snowstorm Fri – Sat.

 
Monday: 23. Partly to mostly sunny. Flurries. Windy. Cold.     

Tuesday: 24. Mostly sunny. Cold. Windy.  

Wednesday: 27. Clouds and sun. Maybe some light snow overnight.      

Thursday: 29. Mix of sun and clouds. Flurries possible. Cold.

Friday: 31. Cloudy. Snow developing. Heavy snow overnight.  

Saturday: 28. Heavy snow ending. Windy.          

Sunday: 34. Sun and clouds. Windy at times.