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Central PA Fall 2018

pasnownut

By pasnownut,
in Upstate New York/Pennsylvania

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AllWeather

AllWeather

Posted
Posted
12 minutes ago, Blizzard of 93 said:

I agree, but the trend has been colder on the models from 12z ,& the 3k NAM in particular has made a significant jump up with snow totals for the LSV at 0z

Ratios will play a large role, but the trend is there.

No doubt the trend is there. Maybe the NAM scores one here. 

Of note is the strong easterly fetch of air by tomorrow morning. Off the mild ocean waters, can be underestimated by guidance. It has burned me several times in the past...

Also, we’re sitting about 3-4 degrees warmer at the surface than the 0z NAM shows in soundings for this time. Not saying it means anything and it could even out in the wash, but something to watch. 

 

Not trying to be a buzz killington here, but these fine line set ups in November tend to pan out more toward the mixy scenario vs. the snowy one.

There’s always an exception though, maybe this one is it? TBD

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heavy_wx

heavy_wx

Posted
Posted

ne_f21.png

This will certainly be a very dynamic event. The image above shows a pretty good setup for heavy precipitation in central PA with the area between the right entrance region of the northern jet streak and the exit region of the southern jet streak (add in some curvature on the latter and that increases the favorable lift for our area). You can see below that this circulation is also tied to mid-/low-level frontogensis; this region of enhanced lift moves northward Thursday afternoon and will be associated with the heaviest precipitation.

ne_f21.png

A forecast profile from this time shows the maximum lift (i.e., negative omega) around 600 mb at UNV. It happens to also coincide with the dendritic growth zone so that, coupled with the near-freezing temperatures between 850-750 mb should lead to very large, wet aggregates around this time.

997605270_Screenshotfrom2018-11-1422-53-03.thumb.png.7827d687ea9a588ac37508786ed15ef1.png

The duration of snow vs IP or ZR is of course predicated on how resilient the cold air will be at low levels. There is noticeable 500-mb confluence over northern New England currently, helping to promote anticyclogenesis and associated cold ageostrophic flow into our region. However, the surface high moves eastward and weakens late Thursday into Friday, allowing for temperatures to warm above freezing the in the 800-700 mb region. Things do cool off again for potentially another round of moderate snow as the energy from the secondary low moves east through the region Friday morning (probably more favorable for areas in eastern PA).

It's definitely a cold airmass for this time of year, but I have been burned before up here with mixing occurring earlier than expected. Will be a fun one to watch!

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MAG5035

MAG5035

Posted
Posted
49 minutes ago, heavy_wx said:

This will certainly be a very dynamic event. The image above shows a pretty good setup for heavy precipitation in central PA with the area between the right entrance region of the northern jet streak and the exit region of the southern jet streak (add in some curvature on the latter and that increases the favorable lift for our area). You can see below that this circulation is also tied to mid-/low-level frontogensis; this region of enhanced lift moves northward Thursday afternoon and will be associated with the heaviest precipitation.

 

A forecast profile from this time shows the maximum lift (i.e., negative omega) around 600 mb at UNV. It happens to also coincide with the dendritic growth zone so that, coupled with the near-freezing temperatures between 850-750 mb should lead to very large, wet aggregates around this time.

 

The duration of snow vs IP or ZR is of course predicated on how resilient the cold air will be at low levels. There is noticeable 500-mb confluence over northern New England currently, helping to promote anticyclogenesis and associated cold ageostrophic flow into our region. However, the surface high moves eastward and weakens late Thursday into Friday, allowing for temperatures to warm above freezing the in the 800-700 mb region. Things do cool off again for potentially another round of moderate snow as the energy from the secondary low moves east through the region Friday morning (probably more favorable for areas in eastern PA).

It's definitely a cold airmass for this time of year, but I have been burned before up here with mixing occurring earlier than expected. Will be a fun one to watch!

I can certainly understand CTPs perspective of having to temper forecast snow amounts with regards to a very uncertain evolution on mixed precip. For the UNV region and surrounding areas I see this as more of snow/sleet and how much sleet mixes in scenario as the central counties should easily remain below 0c at 925mb to the surface.

Even though the high does eventually start moving away and weaken some as the storm advances, it’s still a pretty cold setup especially given it’s only mid-November. An intense push of precip with the initial precip shield with the aforementioned strong lift might render that a moot point if the region (including a big part of the LSV) gets crushed with several hours of heavy snowfall right off the bat. That seems to be where the near term modeling like the HRRR is going.  I personally think it’s going to be more of a 5-8” type deal back in this area but I am certainly aware that sneaky warm air in that 750-850 region could sleet that top end away quickly. If things did end up mostly all snow and we managed to score some off that deform as the coastal takes over this has the potential to be a double digit snowstorm as the Euro/Euro EPS/Canadian/RGEM have been alluding to.

I’m excited either way, today was one of those days you could “feel” something wintry is on the way. 

 

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Voyager

Voyager

Posted
Posted

The only thing this morning is, gotta wonder about surface temps and how they'll play out. I'm sitting at 28f this morning. Five degrees warmer than the 23f that CTP had forecasted for me. High clouds rolled in right before sunset and helped keep radiational cooling at bay overnight.

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sauss06

sauss06

Posted
Posted
3 hours ago, Flatheadsickness said:

I have a felling it may be one of those years. It looks to be active this year hope we all can get the good tracks and big domes . cad to all and big jugs this year. ;)

 

i feel the same. If get the moisture in the fall and winter, like we had in the spring and summer, with some cold air we could be in for a wild ride. 

I'm at 30 degrees, thought we'd be a little cooler this morning.

 

edit- i hadn't read all the posts from this morning, i see others have commented on the temps as well

What are your morning thoughts Matt?

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Itstrainingtime

Itstrainingtime

Posted
Posted
8 minutes ago, pasnownut said:

It’s gonna be a good day. 

Enjoy everyone...no matter how much it piles up.

This is what we come together for. Here’s to a great winter of trackin and playin. 

Nut. 

Yes sir. I thought about days like this all freaking summer. Double bonus to have it come to us earlier than normal. Couldn't ask for a better group to have fun doing this with. I swear Blizz of 93 tracks for about 21 hours a day this time of year. 

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