Central PA Winter '10-'11 Obs/Discussion I

[Itstrainingtime]

Scanner is busy. Trees/wires down all over the Susq. Valley. Just heard a large tree branch fell to a Tractor/trailer on I-83. They air lifted the driver, the branch punctured his chest.

Geez, down this way there's very little wind right now.

Punctured chest doesn't sound good.

[canderson]

I work at the second-highest point on the valley around H g at WITF, inthink the building has been picked up a few times.

[sauss06]

Think we'll get in any of that action next week? It would be nice to have a little snow for the 1st day of deer season here in PA.

[EasternUSWX]

Models now have this storm going into the lakes. La Nina.

[PottercountyWXobserver]

Models now have this storm going into the lakes. La Nina.

Yeah, we all knew this La Nina would be a pain in the a$$ , hopefully the SE ridge minds its own business and keeps out of the NE snow affairs. I might see some snow showers tonight off the lakes. Hopefully the threat right after turkeyday can manifest into a formidable solution. I really hope this -NAO can get its act together and just maybe the PNA can stop being so negative and think positive for a change.

[2001kx]

started snowing here a few mins ago.

was sleet and went to rain / snow mix.

[canderson]

Weather here is boring for the next while, so I've focused on Munich. Looking at models, we might get a blizzard next Thursday!

[Itstrainingtime]

Weather here is boring for the next while, so I've focused on Munich. Looking at models, we might get a blizzard next Thursday!

Enjoy!

Meanwhile, we'll be raining with a strong south wind and temps in the 50's.

[sauss06]

Weather here is boring for the next while, so I've focused on Munich. Looking at models, we might get a blizzard next Thursday!

Find some pub to sit in, drink and watch it snow

[canderson]

No way, walking in a snowstorm is heavenly. Walking in a late Nov Centeal PA rainstorm, not so much!

[PennMan]

I'm at home in Lebanon County, PA for the next several days. Looks like a frontal passage tomorrow afternoon followed by a cool Wednesday. CTP mentions some mixed precip early on Thanksgiving for N Central PA, turning to possibly heavy rains by afternoon. Blech.

Currently 51° here.

[JamieOber]

WJAC just had their winter forecast, below normal temps Dec/Jan, above normal Feb, normal Mar, lots of precip, including snow and ice.

[MAG5035]

Could be an interesting few hours Thanksgiving morning in some spots with regards to a possible wintry mix. Just had a look at the full 12z European and that model actually presents a window of oppurtunity within the 72-78hr timeframe. Brings in some half decent overrunning precip with sub 0ºC 850 and 925mb line in the northern tier briefly dipping thru central PA toward the MD border. New 18z NAM also presents a chance for some brief front end snow.12z GFS was similar but a bit warmer aloft at precipitation onset and thus mainly rain. Obviously, timing is going to be key to seeing anything other than rain at the onset. Best chances of seeing some flakes and/or ice pellets will likely be in the north central (along I-80 and above) and into northeast PA and the Pocono's. Depending on how firm the retreating marginal cold air holds could see some mixing in places like KJST, KAOO and KUNV. It shouldn't amount to anything major, but at least it might make for a slight bit of excitement on what is shaping up to be a chilly and wet Thanksgiving Day.

[Feb]

I just happened to catch Weather World and their fearless forecast for the end of November up until December 22nd. They are calling for a couple of pretty intense cold shots and the said there will be a memorable snow or ice storm.

[Itstrainingtime]

I'm leaving for Florida next Friday for 10 days. Fully expect to come back and see a different landscape by then. Might be one of a few times this winter that those of us below the ridge and valley see much white.

[PottercountyWXobserver]

It's not looking good fella's. The pattern up into Dec 5 brings Lake cutter after lake cutter through the area. Looking at some of the QPF forecast, there looks to be in some places in PA could experience up to 3" if not more over the next 7 days. Could possibly usher in some local flooding as some places are quite damp to begin with.

[jm1220]

The NAM is borderline for some ice/sleet on Thanksgiving across central PA. It would probably be isolated and confined to rural areas and ridges, but it would definitely be a factor for travellers. For most it looks like a 34F rain, but only a small drop in forecasted temps on Thanksgiving AM could make things interesting.

[PennMan]

WJAC just had their winter forecast, below normal temps Dec/Jan, above normal Feb, normal Mar, lots of precip, including snow and ice.

I'm definitely not concerned about a total lack of precip this winter....I am increasingly concerned that much of it could be sleet/freezing rain in State College however.

[EasternUSWX]

12Z NAM dumps like 1" of FZRN on JST. Nothing even in the CTP forecast about it.

[JamieOber]

12Z NAM dumps like 1" of FZRN on JST. Nothing even in the CTP forecast about it.

Yeah, the NAM is really ugly around here T-giving, as is the 0Z Euro.

[Storm Clouds]

12Z NAM dumps like 1" of FZRN on JST. Nothing even in the CTP forecast about it.

1 inch of freezing rain!?! That would not be good for Thanksgiving! What are the chances of seeing frozen precipitation around here?

[JamieOber]

1 inch of freezing rain!?! That would not be good for Thanksgiving! What are the chances of seeing frozen precipitation around here?

Probably not real good in York, although the NAM seems to show a little bit.

[MAG5035]

12z Euro seems to be holding serve with its last few runs with regards to the wintry mix potential Thanksgiving morning. 15z SREFs also are beginning to light up with some probabilities for various P-types.

12 hour snowfall (thru hr 48):

Didn't think yesterday that this would amount to much, as the Euro was the only thing I seen that was really amounting to anything noteworthy. Today there is more model support from the NAM/SREF. As you can see above some pretty solid probs for 1"+ of snowfall, even down into UNV. The bigger issue is going to likely be the freezing rain/sleet potential, and there are pretty high probs in the north central for a period of of icing.

As it stands right now, winter weather advisories might eventually be needed for north central PA (i.e Clearfield, northern Centre and counties north and northeast to NY border). Significance and coverage of this is going to depend on how well the retreating air mass holds and also the timing of precip arrival. Am curious for what CTP has to say.. still awaiting the discussion update. It does appear they're going to have something more to say about the potential tho, as grids now have wintry mix locally (Blair county) and a sampling for even down in Bedford has the same.

[jm1220]

I'm wondering how much of a factor the dry air will be in holding back the onset of precip. I've seen setups like this before in the State College area where temps looked good for a wintry mix in a CAD setup, only to see the onset of the precip be pushed back further and further due to the dry air eating up the precipitation. When it finally would start, there would be an hour or two of sleet and/or snow only to have it go to rain soon after. The GFS especially seems to want to confine the heavier precip to the western half (particularly south) of the state until Thursday night. Even the NAM doesn't have a heck of a lot of precip east of the Susquehanna until the cold front plows through (at which point everyone everywhere will be rain with 850s above 10C). I'd like to see a more pronounced onset of the precip into northern and eastern PA than is being displayed now on most models.

The CAD setup looks very strong though with temps possibly bouncing between 32-34 at the surface with 50+ degree temps just several thousand feet overhead. The NAM shows the sfc being at around 32 in Philipsburg at 3z FRI with an 850 temp of +11C!!

[PSU8315]

I'm wondering how much of a factor the dry air will be in holding back the onset of precip. I've seen setups like this before in the State College area where temps looked good for a wintry mix in a CAD setup, only to see the onset of the precip be pushed back further and further due to the dry air eating up the precipitation. When it finally would start, there would be an hour or two of sleet and/or snow only to have it go to rain soon after. The GFS especially seems to want to confine the heavier precip to the western half (particularly south) of the state until Thursday night. Even the NAM doesn't have a heck of a lot of precip east of the Susquehanna until the cold front plows through (at which point everyone everywhere will be rain with 850s above 10C). I'd like to see a more pronounced onset of the precip into northern and eastern PA than is being displayed now on most models.

The CAD setup looks very strong though with temps possibly bouncing between 32-34 at the surface with 50+ degree temps just several thousand feet overhead. The NAM shows the sfc being at around 32 in Philipsburg at 3z FRI with an 850 temp of +11C!!

The dry air is a valid point, especially given how broad the area of high pressure is in this setup:

[JamieOber]

I'm wondering how much of a factor the dry air will be in holding back the onset of precip. I've seen setups like this before in the State College area where temps looked good for a wintry mix in a CAD setup, only to see the onset of the precip be pushed back further and further due to the dry air eating up the precipitation. When it finally would start, there would be an hour or two of sleet and/or snow only to have it go to rain soon after. The GFS especially seems to want to confine the heavier precip to the western half (particularly south) of the state until Thursday night. Even the NAM doesn't have a heck of a lot of precip east of the Susquehanna until the cold front plows through (at which point everyone everywhere will be rain with 850s above 10C). I'd like to see a more pronounced onset of the precip into northern and eastern PA than is being displayed now on most models.

The CAD setup looks very strong though with temps possibly bouncing between 32-34 at the surface with 50+ degree temps just several thousand feet overhead. The NAM shows the sfc being at around 32 in Philipsburg at 3z FRI with an 850 temp of +11C!!

Good point.

On the other hand, I have seen it not warm up here near as fast as predicted. Christmas Eve 2008 is a prime example.

[jm1220]

Good point.

On the other hand, I have seen it not warm up here near as fast as predicted. Christmas Eve 2008 is a prime example.

That's definitely possible too. The cold air is coming from a cold source-from snowcovered eastern Canada, and the high is quite strong. However, the flip side is that the colder air is likely pretty dry and will take a while to eat through. The NAM has a good slug of precip that makes it into PA and into the cold initial air, but the GFS is a lot less enthusiastic about how much precip makes it into the cold air (I don't buy the GFS temp profile, the NAM will be far closer to being accurate in this setup as usual). Eventually by Thurs night, models agree the initial WAA shot of precip mostly gets eaten up and the cold front provides the rest of the rain. By 21z Thursday, a little over 0.25" liquid eq. falls near UNV on the GFS, while the NAM is around 0.75", and the NAM tends to be overly wet. By then, it should be rain for 95% of people given daytime heating and lack of snowcover anywhere around the area.

I think most areas west of I-81 and north of I-76 get some snow and then sleet/maybe freezing rain in spots and then rain. It's a big debate however how much and how heavy it is, which would obviously affect impacts. If it does come in fast and thump, there could be a few inches of slop before the changeover and then abatement of precip.

[sauss06]

Local mets said this am here in the susq valley, we will have mixed precip overnight..

[JamieOber]

That's definitely possible too. The cold air is coming from a cold source-from snowcovered eastern Canada, and the high is quite strong. However, the flip side is that the colder air is likely pretty dry and will take a while to eat through. The NAM has a good slug of precip that makes it into PA and into the cold initial air, but the GFS is a lot less enthusiastic about how much precip makes it into the cold air (I don't buy the GFS temp profile, the NAM will be far closer to being accurate in this setup as usual). Eventually by Thurs night, models agree the initial WAA shot of precip mostly gets eaten up and the cold front provides the rest of the rain. By 21z Thursday, a little over 0.25" liquid eq. falls near UNV on the GFS, while the NAM is around 0.75", and the NAM tends to be overly wet. By then, it should be rain for 95% of people given daytime heating and lack of snowcover anywhere around the area.

I think most areas west of I-81 and north of I-76 get some snow and then sleet/maybe freezing rain in spots and then rain. It's a big debate however how much and how heavy it is, which would obviously affect impacts. If it does come in fast and thump, there could be a few inches of slop before the changeover and then abatement of precip.

Yeah, this has be something forecasters aren't happy to see for a holiday, a tough call like this.

[Itstrainingtime]

Local mets said this am here in the susq valley, we will have mixed precip overnight..

Yes, even Joe Lundberg (the warminsta himself) indicated snow/sleet here in our area overnight. I was a bit surprised to hear that this morning.

Even though the air temperature isn't impressively cold, it felt colder this morning than what the thermometer indicated. Dry, cold air mass in place...