Central PA - Winter 2020/2021

[MAG5035]

Merry Christmas everyone, it did somehow manage to be a white one here.

[Blizzard of 93]

It’s snowing again now in Marysville!

2 rounds of snow on Christmas Day is a win!

[Jim Marusak]

Susquehanna's crested in Conklin, Binghamton, and Vestal NY. still looking to have a moderate flood up and down the North Branch, but not as ugly as feared this morning.

[Blizzard of 93]

Steady light snow continues in Marysville!

The roads & all surfaces caved!

Beautiful way to end Christmas evening!

[Itstrainingtime]

14 minutes ago, Blizzard of 93 said:

Steady light snow continues in Marysville!

The roads & all surfaces caved!

Beautiful way to end Christmas evening!

Yes sir - we've had flurries or very light snow for most of the day actually, but in the past hour or 2 beginning to see cars covered and some spots on my road. Certainly a very festive scene today!

[paweather]

Wow!!! What a surprise. 

[CoralRed]

Wunderground is predicting 1.57" of rain next Thursday for Williamsport.  We got very little rain here for months on end.  Much of this summer and fall was like a dream with day after day of blue skies (our frequently overcast skies magically gone) and no rain.  I don't know when the last time was when we had such a period or when we will again.  I figured there would be a time when we'd be getting the rain we didn't get for so long.  But I didn't expect to get our biggest snow ever to be followed by warm temperatures and heavy rain that washed much of it away a week later to be followed a week later by another big rain accompanied by spring-like temperatures. 

A lot of extremes, as I have said before and someone pointed out was typical of 2020.  I hope 2021 is more average, in every way.  

 

[Greensnow]

Christmas miracle up here in Clarks Green! Grinch wiped away the pack but heavy snow showers this evening put a quick inch on the ground. Still snowing moderately.

 

[Voyager]

Ugh...that would be a nightmare for me...

[CarlislePaWx]

Hi all.  Was out visiting relatives all afternoon into this evening.  Glad to see I wasn't the only recipient of the somewhat unexpected snow activity.  It sounds like points east of me had a longer steady period into this evening.  Back at my last post around 1:00 I did manage to measure officially 0.1" of snowfall for today.  So happy to have many on here declaring a white Christmas.  Congrats to all.

[Blizzard of 93]

Good morning everyone!

MDT recorded .3 inches of snow yesterday making it an official White Christmas for Harrisburg!

[pawatch]

16 hours ago, Jim Marusak said:

Susquehanna's crested in Conklin, Binghamton, and Vestal NY. still looking to have a moderate flood up and down the North Branch, but not as ugly as feared this morning.

West Branch up here crested at 17.59 up here. Was predicting 19' 

136,000 cubic ft per second is a lot of water moving really fast. 10,000 is the average so it's basically 13.6 times your average flow. 

Be Careful!!

20 degrees for the low this morning. 

[Blizzard of 93]

Had anyone heard if something is wrong with the thermometer at MDT?

At 9am they are showing a current temperature of 38 degrees. The next warmest location in PA is Philadelphia at 26 degrees currently.

Yesterday, it also seemed like their temperature was way off from what surrounding locations were showing.

[Eskimo Joe]

Self quarantined for 2 weeks and a negative COVID test allowed us to see the in laws in Mt. Joy. We were rewarded with a dusting of snow last night.

[Jim Marusak]

1 hour ago, pawatch said:

West Branch up here crested at 17.59 up here. Was predicting 19' 

136,000 cubic ft per second is a lot of water moving really fast. 10,000 is the average so it's basically 13.6 times your average flow. 

Be Careful!!

20 degrees for the low this morning. 

looks like Wilkes Barre is now cresting near 26ft (~150000 cfs). That is a lot less than was predicted, which is good news for a lot of people downstream on the north branch.

[paweather]

Looks like a repeat from Christmas Eve on NYE.

[paweather]

Swatara Creek near Hershey this morning:

 

[canderson]

2 hours ago, Blizzard of 93 said:

Had anyone heard if something is wrong with the thermometer at MDT?

At 9am they are showing a current temperature of 38 degrees. The next warmest location in PA is Philadelphia at 26 degrees currently.

Yesterday, it also seemed like their temperature was way off from what surrounding locations were showing.

I tweeted this to CTP actually - I agree. 

[paweather5]

37 minutes ago, paweather said:

Looks like a repeat from Christmas Eve on NYE.

In a big way on the gfs. Wonder how the River will handle this. 

[paweather]

11 minutes ago, paweather5 said:

In a big way on the gfs. Wonder how the River will handle this. 

It should be interesting after Thursday’s rain. 

[canderson]

MDT’s temp sensor has been fixed - now showing 26. 

[CarlislePaWx]

One model run later, the 12z run gives the qpf in many spots a 30 to 40% haircut.

[Blizzard of 93]

20 minutes ago, canderson said:

MDT’s temp sensor has been fixed - now showing 26. 

Nice!

Did they say what the issue was with it?

[canderson]

5 minutes ago, Blizzard of 93 said:

Nice!

Did they say what the issue was with it?

Nope, maybe just a reset or something. It was working yesterday late afternoon, who knows.

[Ruin]

6 hours ago, canderson said:

MDT’s temp sensor has been fixed - now showing 26. 

what was it doing showing a to high temp?

[showmethesnow]

Now whether the models are portraying the impacts we are seeing from the Strat PV SSW/split correctly down into the lower levels can be debated. But what they are currently projecting is irritating as hell.

If there are any questions as to whether a favorable N Atlantic can trump a hostile PAC what is currently being portrayed on the models should answer that question. Give me that blocking as currently projected on the 5 day mean in the extended and I would say 9 out of 10 times our snow chances would go fairly significantly up as it would tend to force a favorable storm track in the east. But what we are seeing from the PAC (strength, placement, configuration of 500 mb PV) is simply overwhelming the CONUS. 

Now we are seeing episodes of somewhat decent spiking with the EPO and northern PNA (North stream driven) which would generally be favorable for in the East as to wavelength and the ability to drive cold into the East. But the portrayal of the 500 PV and how it is configured it is not allowing for the creation of any decent cold air on our side of the globe nor the tapping into of decent cold air from the other side of the globe through cross polar flow. But still, considering the time of the year this is something we could potentially overcome. But what we are seeing with the mid-latitude flow is overwhelming this. 

As you can see we have that big blob of blue around Alaska which is the PV. What I want you to note are the blue anomalies that extend down from that feature into the SW and into the west central portion of the US into the lower latitudes. This is signaling that we are seeing energy diving into the west creating episodes of troughing which results in a corresponding response of ridging in the East and off the coast (WAR, Western Atlantic Ridging).  I am sure most of you have noted the recent tendency for strong East coast ridging popping up in front of incoming systems driving the systems into the Lakes. This look below argues for a continuation of this general storm track though it may be adjusted somewhat southward as we are seeing better blocking overtop (putting the farther north latitudes in the East more so into play). 

So how could we possibly get those farther south into any possible action? The favored way is if we see those strong positive height anomalies in the western Nao domain shifted farther south towards southern Canada. This would shift the storm track southward as well. Besides that, we are highly dependent on timing of different smaller scale features to drag the boundary farther south in advance of any incoming systems. Depending on timing though, is quite often a losing proposition for most of us.

 

[pawatch]

Looks like it is going to be a crappy weather week.

Thanks for the post showmenthesnow!

[Blizzard of 93]

It’s just a matter of time until the blocking pays off for our Winter Storm chances,

One the -NAO blocking shifts a little to the west, we should be in business. 

We just need to stay patient.

[showmethesnow]

Debated somewhat on posting this as it is happens towards the end of the extended and it involves something that the models have mishandled quite often in prior years (energy dumping into the SW). So this setup could very well be a figment of the models imagination. This is day 16 on the 06Z GEFS. Now some will look at this and key on the lower heights in the central portion of the country and think there is a possibility there as this snapshot looks somewhat favorable. But short of well placed timing with short waves I think the odds strongly favor this once again being a cutter into the Lakes with possible redevelopment to the east as it encounters the blocking overtop. Any redevelopment would be far to the north as to where most would not benefit from any such redevelopment. And the reasonings for my thoughts are shown on the second map below. 

 

What we need to do is look at the evolution of this shortwave prior to the snapshot above. This is 72 hours prior. Note we are once again seeing what I discussed earlier this morning, energy driving down into the southwest bumping up heights in the East. So once again we should see the storm track adjusting to the N and W in the East. In fact this is exactly what we see when we look at surface pressures.

 

 

What is potentially more significant is what we are seeing with the development of lower latitude ridging in the West, as well as what is occurring with the surface lows that have been prevalent in the Gulf of Alaska. What we are seeing with the ridging in the west is that it forms and then begins to move eastward starting to encroach in the southwestern US and connecting to the northern based +PNA and -EPO. We see this and it should effectively cut off the ability of energy from diving down into the SW from energy revolving around the PV. No Southwestern trough and we should not see the bumping up of ridging in the East which is creating our cutters. We see this look actually verify and move forward and we probably end up with a gradient pattern across the CONUS as strong heights (blocking) should develop across the whole of Southern Canada. Think bowling ball cutoff lows. Now whether temps would cooperate may be another story. And in that regard we are seeing a positive as well as we are seeing surface low pressures migrating from over the Gulf of Alaska into the Aleutian islands. If this look is real we could potential move fairly quickly into a very favorable pattern for at least portions of the East depending on where the boundary would set up. ***GEFS is more aggressive with this but EPS also has indications of this as well.***

 

[MAG5035]

Might not want to sleep on this New Year's event potentially becoming some kind of a wintry mix event in C-PA.  Models have been toying around with sending the first piece up into the lakes, pulling a front across and holding back a good bit of energy for another wave to roll up. While the southern wave builds, models have been getting some high pressure in place over us/just to our north. Positioning of the mid-level features (850 & 700 lows well west) definitely aren't looking ideal for an extended snow event, but get that high over us for at least a bit and we probably are going to be dealing with some kind of messy mix event on at least the front end.