MAG5035

It’s kind of misleading they announced that when they’re set to announce the next batch of counties today that will be going to yellow. And the way the news sources titled it, it’s really misleading. I guess I didn’t realize the previous state-wide stay at home was to expire today. They’re basically extending that out for the red counties but they will still be evaluating counties that can move to yellow. There’s not really any change from how they’re running their phased reopening plan, which looks to be evaluating counties on a weekly basis.

The synoptic event def doesn't look as good as it did. The system's timing overall is a bit faster by about 3-6 hours and the low seems a tad north and a bit later with getting going. Pretty much the snowy NAM is looking more like what the Euro has been looking like as the Euro has been the least enthused with wintry precip in PA. Also haven't seen an overly strong signal on ensembles other than maybe the SREF. So I think the changeover to snow is looking like it's going to stay confined to higher ground. It's still going to be crazy cold first thing Saturday morning and still a chance of some pop up frozen showers in the afternoon.

I dunno if it's really all that strung out, the NAM looks like it's coming more into line with what the other models have been showing... having a bigger portion of the event rain especially outside of the high ground. Timing is important with this. If this stays slow enough, the main part of the event is late in the day into at least the first half of the night... taking away the sun part of the equation. You would need crazy rates in the middle of the day this time of the year, but toward dusk (after 18z) and nighttime you can start accumulating with more modest rates. We have the things on the playing field to make this happen, having such a cold airmass pressing in with this storm system passing under us. It's going to be interesting to see what happens. I definitely think the high ground is going to see at least a few inches, but the wild card is going to be if this actually gets to lower elevations or even the Sus Valley. This won't affect potential for showers/squalls on Saturday. The core of the mid-level cold will either directly target PA or pass just north depending on models on Saturday behind the system. GFS and NAM are taking it right through PA with sub 516 thicknesses.. which is insane. -40ºC 500 mb temperatures are generally not something seen over the US in May. PA gets into -20 to -22ºC temps at 700mb (10,000ft) and -10ºC 850 temps. Even the 925mb temps are well below freezing. I bet some of the higher Laurels and north central elevations never get above freezing during the day Saturday. But you put that really strong May sun and heat the surface with such cold air aloft and your going to get some stuff to pop up.

Anything frozen would go over to the 20-21 season after July 1st. To properly tally average annual snowfall, it's done over a 12 month period from July 1-June 30/31 so the annual snowfall total covers only one actual winter season.

I once thought as you do. Those last two winters I've tallied snow here in my signature at 54.6" and 52.2" are average winters at my location at the foot of the Laurels. The 16.2" is pretty much 30% of normal and the wall to wall futility was something i've never seen. I was completely over this winter by the beginning of March from a hitting the slopes standpoint as there was never a point this winter the local resorts had a period of even half decent conditions. But you know what? I'm all in on this possible debacle Friday night. It's not likely anything else going on right now is "normal" anyways lol. Plus a paste bomb may actually help insulate the vegetation some with low temps Sat morning in hard freeze territory (mid 20s) Sat morning back this way. Having a trace and having measurable are two different things. If the flakes are flyin in the air, that's a T for the day. Grapuel also counts as frozen precip too so a non or little accumulating grapuel shower would go down as a T as well... and that's definitely on the table Saturday in the LSV. Lancaster has probably never had a recorded measurable event in May but that 1977 event for instance may have given them at T. Either way, any frozen that deep into the LSV in May is extremely rare. I dunno if State College has anything like this but NWS Pittsburgh has a whole webpage of miscellaneous snowfall data for PIT going back to 1884. Their latest recorded snow was May 31, 1893 (T) and latest accumulation of snow was 0.5" on May 25, 1925.

Rain and mangled flakes currently.

I was just about to comment that I saw it falling on the 511pa camera at the Penfield/153 exit up there.

Lol 0z NAM doesn't have the really heavy amounts but it snows on the whole Sus Valley and gets flakes down to the I-95 corridor in central VA.

I'm not sure on definitive dates. I would imagine more stations than you might think have recorded a T in May, but as far as measurable? Aside from likely KJST and KBFD I don't know offhand who else. Any measurable more than a trace in the LSV is likely uncharted territory in at least the last several decades. As far as may snowstorms, May 9-10, 1977 apparently had one in Upstate New York and southern New England. https://www.boston.com/weather/weather/2016/05/09/on-this-day-in-1977-the-weather-was-bad-as-in-13-inches-of-snow-in-worcester-bad

Hah 18z NAM must think so. That's not even done at 84 hours. Welcome to happy hour in May I guess.

The difference between the Euro and GFS for the weekend comes down a choice between insane and more insane. The GFS has been dumping the core of the 500mb PV right over PA while the Euro has been swinging it through NY State. Going to be crazy cold for mid-May either way, but the difference would be the core of the 500mb would provide the best instability for the rain/snow/grapuel showers that are sure to develop with daytime heating. The 500mb air at the core of the PV is progged at -40ºC, which I'm not sure if that is some kind of record over this part of the US but it's def not often you see air at that level that cold even in the winter. I'm pretty sure it would be the coldest ever observed in May over the northeastern US. Gonna have the watch the coastal wave later Friday too, the sharper GFS has the low going more underneath and has what looks like a bit stronger of a system. Would likely make a potentially more snowy scenario in the higher elevations of western and possibly even central PA with that 500mb low dropping. The system is also timed later Friday into Sat evening so it would take the strong sun out of the equation. A wet snow bomb is def on the table in the higher ground. Either in interior PA and/or upstate NY.

I think we're likely going to come out of this after mid-month, as modeling seems to flatten the trough and eventually show some ridging in the east and a bit of a western trough. Given how late in the spring we're going to be by that point, this is definitely looking like a candidate for straight to summer when the pattern breaks down and/or reverses. Saturday is going to be the low point for this whole thing though as an unbelievably cold airmass for this time of the year drops pretty much through PA. Like I said yesterday, the 1000-500 thicknesses are insane and something I've never seen in PA in May.. with the GFS easily sub 522 over all of PA and Euro sub 516 over a big portion of the state. Let me put it this way, if we had thicknesses like that in the middle of January we'd be concerned about it being too cold and supresssing the storm track. Or another way, if this type of thing actually dropped down in the middle of winter the thicknesses would be much lower than that (probably a 2015 style cold outbreak). That's generally not achievable well into May at the low levels, but the mid level temps are what's driving such low thickness values. When the core of this 500mb low moves through PA Saturday, models are progging nearly -40ºC (!!) at 500mb, -20ºC at 700mb, and -5 to -10ºC at 850mb over all of PA. That's crazy this time of the year. GFS generates a couple hundred j/kg of CAPE (Euro a bit north) Sat afternoon. The May sun is going to heat surface temps into the 40s or maybe even 50 or so in the LSV, so probably don't need to tell you the potential is there for robust diurnally driven showers with how cold it is aloft. I think anywhere in the region could see frozen on Saturday, either in grapuel or snow (or both). Grapuel counts as frozen precip too. It's going to be so cold aloft that a heavier shower is going to overwhelm the lower part of the column, and you'd only have to go up to about the 925-900mb level to get below freezing. The higher ground of west central and north-central PA could see two separate snow events in addition to this with tomorrow's system as well as a system progged on the models that ejects east later Friday underneath the pressing anomalous 500 low.

Columbia County is actually in the north-central region with it's almost 300 cases, but that was left in the red. They stuck strictly to the health regions with the first round of counties they're bringing to yellow except for that one specific county.

I didn't realize Clinton had enough new cases to be over that 50 per 100,000 threshold in 14 days.. and they're in a reopen region. Huntingdon has seen a pretty big jump in cases the last several days that has been noted to be from an outbreak of the virus within the state prison in the city of Huntingdon. That was even specifically addressed by Dr Levine whenever one of our local state reps brought up the overall low numbers back this way and the prospects of being the next to go to yellow. It does mention on that map that the 50 per 100000 rate isn't the only thing utilized. Even Allegheny County which includes Pittsburgh metro and a majority of the greater Pittsburgh region is easily under 50 (26.6). I know that was brought up a few days ago and the main reasoning for there to remain red was something to the tune of not risking high population density areas being on the first round of counties if I recall correctly. That interactive map is also using the two week period from April 13-27, so it'll be interesting to see a more updated map. If they're updating this map once a week, we'll probably be due to see a new map within the next couple days as that April 13-27 period is a Monday-Monday timeframe, and the next one would be April 20- May 4. One also has to remember that 50 per 100,000 people doesn't mean staying under 50 cases per county. The actual case numbers to get that rate varies with the county's population. Franklin County with it's 155027 people needs to stay under 78 cases in two weeks to achieve that. A county like Clinton County, which was slightly over the 50 per 100k (56) has a population of 38,362.. which would equate to staying under just 20 cases in two weeks to achieve that criteria. Saying 50 per 100,000 is just a fancy way of stating 0.05%. So if anyone wants to see what the number is for their county, you take the county's population and multiply it by 0.0005.

Models are still playing around with high elevation snows on Wednesday, with the GFS/Euro/NAM lighting up the Laurels and west central PA blue with the system passing to the south. That's not even the craziest portion of the week in my opinion. That comes Saturday as the models prog the core of a major closed 500 low to pretty much move through or just north of PA. In term's of negative 500mb height anomalies it's easily the biggest in the hemisphere. New GFS sends sub 522 thicknesses and the Euro has had sub 516 into PA in previous runs. I've never seen anything like that before in May or really anything close to that. There will absolutely be frozen precip seen in a majority of the region this weekend if that 500 low dumps all the way down like the new GFS shows. That's also generating 100-200 j/kg of CAPE on Saturday under the strong May sun, so squalls could be pretty wild under that scenario.

I see one official station that's cracked 80ºF so far and its actually KIPT at 81ºF. About 75-76ºF here currently.

You gonna run it next weekend? Lol

I've witnessed May snow twice and it was in a two year period... May 12, 2008 on the heels of a very deep coastal low and also May 11, 2010, the latter of which I have pictures of. It can and does happen. The pic was taken at a place that was about 1700' elevation.

I said back on Tuesday last week I was concerned with the pattern and late freeze potential during the first half of May in terms of gardening/farming. If you have a reasonable way to protect your garden (like covering plants), I'd def look into doing so.. especially the period next weekend thru likely several days beyond that where low temps below freezing look like a strong likelihood at least a time or two.

Yea that's what I would have figured, I didn't know they could switch to a different mode for that.

One thing I noticed while the rainstorm was unfolding yesterday was the doppler estimates definitely seemed to be low-balling what the ground observations were, which might have been a result of the raindrops themselves. The high PWAT's and deep southerly flow likely yielded efficient rainfall, but small droplets with the absence of much of a convective element that would have had the downpours with the large droplets. I only had around an inch or so back this way, but the majority of the event was the fine raindrops. If that was how the heavier rain was over in the Sus Valley, sometimes the doppler can low ball that. Especially over there where the radar beam is higher up.

Looks like they ended up strictly using those health regions to determine that, despite a lot of push for not strictly using the regions as a whole and allowing individual counties that meet the criteria to open up. The south-central region in particular really displays the flaw in this. It really screws this area where my home county (Blair) as well as Bedford, Huntingdon, and Fulton have been nowhere near that 50 cases per 100000 in two weeks threshold and don't even have 100 total cases between the 4 counties (88) and we get lumped in with York, Dauphin and Lebanon that have over 1800 cases between those counties. And Centre just to the north which is directly connected to Bedford and Blair via I-99 has 90 cases in that county and they are lumped with the north-central region so they'll be able to start reopening. I def don't agree with that health region approach. They issued the stay-at-home orders on a county by county approach when this started so why not now trying to ease restrictions.

Haha this storm looks more like the type of system that causes the big flood after the one that has the 1040 high and buries us with snow.

Seems like the best plume of precip is residing up I-81 to H-burg and then up the river to IPT currently. That's coinciding with main part of the moisture fetch from the Gulf. This will eventually progress east across the rest of the state, where secondary wave slows the frontal passage some and is why eastern PA is under more of a flood threat this afternoon. There's another area of heavier precip in west-central PA as well, which may consolidate some with the other area later on today in eastern PA as the front slows down. I had been thinking this event as a 3-6 hour period of the heavier rain within the overall event.. which is the key to if any flooding ends up occurring. The flood threat is looking more on the minor end with the poor drainage and smaller waterways, although the Main Susquehanna should at least see a pretty significant rise.

It's been the moisture more than the temps for me. It's been cool but not really too crazy temp wise here. Just the continuation of the wetter than normal conditions that have been the norm more often than not the past couple years.