Monday Morning 12/9 Weather ... updated Friday

Are you ready for some snow?   It is coming. the first real snow for our area, and a third snow for Philly and other areas to our south and east. The snow should start Sat mid morning as light snow. IT will stick pretty quickly, as the ground will be cold. The snow will stay steady and become heavy mid afternoon through late evening (3 pm - 8 pm is the window for heavy snow). due to the cold air being supported by a high to our north, it will be 98% snow with a glaze of ice at the end as the main precipitation ends.  

The models are painting a picture of up to 10" of snow, due to high snow to liguid ratios (old rule is that 10 inches snow = 1" of rain). I expect it to be closer to 12:1 and given .66" of liquid equivalent you might expect 8" of snow to accumulate.

the dry slot I talked about (see images below), will cut off our moisture so that will limit our accumulations some. I have seen it before and often we get cut off right around 6" in these type of set ups. So models say more, history says to be careful. Due to this dry slot, we lose the high clouds that seed the precipitation process, and as a result the moisture is all low level, and that often leads to drizzle, or freezing drizzle. This is where I expect to see the glaze of ice to come from.  

Saturday Forecast:  

Snow arriving during the morning. Cold. Snow increasing and becoming heavy during the mid afternoon. High: 29. Heavy snow continuing into the evening and ending by 8 pm. Some freezing drizzle possible during the overnight. Total snow: 6"-8" with a glaze of ice on top. Low: 25.

Sunday Forecast:


Blustery, with some breaks in the clouds in the morning, but becoming cloudier for the afternoon. Not as cold. High: 36. Low: 19. 


Enjoy. 


 

Green colors indicate moisture in the atmosphere. Identify PA and notice to the south and west what looks like a tongue of white aiming toward us. That is the so called "dry slot". It will cut off the precip. This map is valid at 10 pm Saturday.

This image shows expected precipitation from this storm. You can see that our area is being shown to have between .75" and 1". I think that is a little overdone.

There really is not a lot to change in the forecast, except for some tweaks here and there. Today is cold, and tonight it will probably not get to 8 as I expected, but I am leaving it alone because if it is clear and the winds die down the temp will drop rapidly. 


Onto the weekend. Snow looks to arrive Sat morning and continue into Sat night. It should be an all snow system, with maybe a little ice at the very end. Sunday is looking good. Some sunshine, breezy, with temps in the mid 30s. The snowfall looks to be about 4-6" at this time. 


This will not be a major storm. It will remain cold, and with snow on the ground it will be quite cold early next week. A brief warm up will likely come next weekend (21-22) but then colder for Christmas week. In fact, Christmas week may be one of the coldest Christmas weeks on record across the nation. It looks ugly, ugly cold in the West and central US, with just typical winter cold in the east. 


Update tomorrow morning. 

Good morning. Well, the snow yesterday made it to Lebanon and Myerstown and everywhere SE of there. Not much here. Intense banding to our east killed the snow here. recall my post on Monday about the "yellow" band on the predicted radar.  Small systems are notoriously difficult to predict. 


On to the next storm which is much bigger. IF you look to the left you see a forecast for Sunday morning at 7 am. This is the latest upper level forecast and is for the exact same hour as the image from the Monday post. If you notice the southern (yellow/brown) energy is further east and ahead of the great lakes energy. The adjustment is occurring. I expect further changes and a big storm to develop along the east coast late Sat into Sunday. 


Fully expect snow to develop on Sat afternoon and continue into Sun morning. I do not think we will be in for a major snow, that should be further North and east. But several inches are very likely from what I see at this time. The set up at this time is not the most favorable for us to get major snows as the so called dry slot will cut the moisture off earlier here than in others places to our NW. NY and NE could get hit quite hard. behind this will be some very, very bitter cold air. Again, i would not be surprised if we have 4" of snow of the ground that we get near or slightly below zero come Tuesday morning of next week. 


All in all the forecast I have out below looks good. Another update coming tomorrow morning. Until then enjoy the day God has given you.  

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Icy Monday Morning:
Now that I am able to update (tech issues) I will do so. But I must say the weekend forecast turned out pretty good and about as expected. Now we turn to this cold and wintery week and for the foreseeable future. Winter is here …

The bitter and record setting cold that has camped out in the western and central US for the last week (as cold as -40 in Montana and they are still below zero this morning), will shift east, but it will moderate and not be as extreme cold. The west will warm up and the east will chill down even more. As this cold comes east one more wave will bring a burst of moisture through on Tuesday in the form of snow. This system has me concerned that we may be in for a surprise.

Looking at the image to the left, which is a predicted radar picture for Tue at 10 am, shows a bright yellow band slicking NE through SE PA just to our east. This band would represent heavy snow. Did you watch the Eagles-Lions game in Philly on Sunday?  This is what this yellow band could do. But where will it set up?  Likely to our east. but it will impact someone with several inches of surprise snow, in  the SE half of the state. This system will have moisture and dynamics. I am expecting 2-3” out of that at this time. 

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After this front, it turns cold for Wed through Fri with highs in the 20s, and lows in the lower teens to single digits due to snow cover. Coldest nights will be Wed and Thu.
Meanwhile a new system will be coming through the SW US and moving east. It will become a weather maker for us. 

The picture to the left show the potential for this system. The yellow/orange stuff over Alabama/Missippi (called vorticity) is player #1 and the stuff over the Michigan/Great Lakes is player #2. Model are notorious at moving #1 too slow and #2 too fast. If that is the case ... #1 is then ahead of #2 and we have a bigger storm with more moistrue as the two work together as a team rather than against each other as the the image to the left shows. 

The Thanksgiving storm 2 weeks ago was predicted to be a snowstorm at first by the models due to the same error, and you know that turned out. It came so far west that it was mainly a rain storm. I think this system will be bigger and more impacting due to poor model handling. This should be a late Sat – Sun system. I expect it to be mainly snow, but rain will not be far away. Updates will have to be made during the week.

An active week and it should stay active for the next few weeks. 

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Specifics:

Today: Cloudy. Drizzle, cold and raw. High near 36. Low near 30.

Tuesday: Cloudy, snow arriving by 8 am. It could come down hard at times, but ending by mid afternoon High: 31. Low: 18 Total snow 2-3" (watch out for that band!)

Wednesday: Sun and clouds, flurry or two, cold. High: 25, low: 14

Thursday: Sun and clouds, cold.  High: 23 Low: 8, with colder valleys.

Friday: Sun and clouds, cold. High: 28 Low: 18

Saturday: increasing clouds. Some light snow arriving late. High: 35 Low: 28

Sunday:  Snow ending.  Becoming partly sunny, and breezy but cold. High: 32 Low: 13

Hint thru Dec 22: Very cold start to the week with arctic high pressure right on top of us, with some nights approaching zero for lows and colder locales below! Ouch. After that any warm up that comes will be brief and unimpressive. It seems that we are locking into a cold and wet pattern for now. Some light snows possible early in the week, with a bigger system toward the end of the week/weekend